LESSONS ON ELEMENTARY SCIENCE SAlAfC Cornell IDlniversttig OF THE flew ^ovk State Colleee of agriculture ^,....2..i.aX iu.e.ii>.hf>..: Cornell University Library Q 181.S17 Longmans' ob ect iessonsihints on prepar 3 1924 002 932 204 Cornell University Library The original of tliis book is in tine Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924002932204 OBJECT LESSONS Dans les premieres operations de I'esprit que les sens soient tous ses guides. Point d'autre livre que le monde, point d'autre instruction que les faits. L'enfant qui lit ne pense pas, il ne fait que lire; il ne s'instruit pas, il apprend des mots. — Rousseau: Amile LONGMANS' Object Lessons HINTS ON PREPARING AND GIVING THEM WITH FULL NOTES OF COMPLETE COURSES OF LESSONS ON ELEMENTARY SCIENCE BY DAVID SALMON AUTHOR OF " LONGMANS' SCHOOL GRAMMAR " AND " SCHOOL COMPOSITION " REVISED AND ADAPTED TO AMERICAN SCHOOLS BY JOHN F. WOODHULL PROFESSOR OF METHODS OF TEACHING NATURAL SCIENCE IN THE NEW YORK COLLEGE FOR THE TRAINING OF TEACHERS NEW YORK LONGMANS, GREEN, AND CO. 189s X. Copyright, 1892, By LONGMANS, GREEN, AND CO. CONTENTS PART I. HINTS ON PREPARING AND GIVING LESSONS Should Science be Taught? When should Science Teaching Begin? Subjects of Lessons . . Matter of Lessons . Notes of Lessons . . . Illustrations . , . . PAGE I 5 8 •4 i6 PAGE Language 25 Questions 27 Telling and Eliciting ... 32 Emphasis 35 Sumffiary 36 Recapitulation 36 PART II. NOTES OF LESSONS FIRST YEAR. A. LESSONS ON COMMON PROPERTIES. Solvents and Solutions Crystals, Salt-making Suspension. Porosity Filters Sugar 4' 43 44 46 47 Plastic Substances 49 Bricks -50 Elasticity 51 Indiarubber 53 Longmans' Object Lessons B. LESSONS ON COMMON ANIMALS. The Cat 54 The Dog 56 The Horse 58 The Cmu 59 The Ass 61 The Sheep 62 The Pig 63 The Mouse 65 The Hen 66 The Duck 68 C. LESSONS, ON PLANTS. Wheat, Barley, and Oats Rice Maize or Indian Corn . Some Edible Roots . . Some Edible Vegetables . 69 71 72 73 74 Cocoa 75 Coffee ;. 76 Oranges and Lemons ... 77 The Oak 78 SECOND YEAR. A. LESSONS ON COMMON PROPERTIES. Hard and Soft Substances . . 80 Fusion 81 Ductility, Tenacity, Malle- ability 82 Iron^ 85 Lead ... .... 86 Copper Tin . Zinc . Pins . Pens . 89 90 91 93 B. LESSONS ON ANIMALS. The Lion and the Tiger . . 94 7^he Wolf and the Jackal . . 96 The Elephant ...... 97 The Camel 98 The Bear 100 The Hare . 103 The Beaver . 104 The Swallow 107 The Ostrich 109 The Herring ... ..ill C. LESSONS ON PLANTS. Cotton 113 Cork ......... 114 Leaves iij Tea 123 Tobacco 124 Contents THIRD YEAR. A. LESSONS ON ELEMENTARY CHEMISTRY AND PHYSICS. Oxygen 126 Nitrogen 130 Carbonic Acid Gas . . . .131 Hydrogen 132 A Burning Candle . . . .133 PAGE Matches 135 Coal-Gas 136 Ventilation 138 Winds 140 Rain and Snow 141 B. LESSONS ON ANIMALS. Frogs and Toads 143 The Crocodile 146 Snakes 148 The Butterfly 150 The Bee 152 The House-fly 155 The Ant 156 The Spider 157 The Snail 158 The Earth-worm 160 C. LESSONS ON FLOWERS. Wild Mustard 161 The Phlox 163 The Buttercup 165 The Cat-mint or Catnip . 166 The Tulip 167 The Daffodil 167 The Garden Pea 168 The Daisy 169 The Dandelion 1 70 Comparison 1 70 FOURTH YEAR. A. LESSONS ON ELEMENTARY PHYSICS. Solids, Liquids, and Gases . .173 Effects of Heat 1 74 Pressure of Liquids . . . 178 Pressure of the Air .... 180 The Pump 184 Equilibrium of Liquids . . . 189 Capillary Attraction .... 193 Magnets 194 B. GENERAL LESSONS ON NATURAL HISTORY. Mammals .... . . 196 Reptiles The Whale 197 Insects .... . . The Bat .... . . 199 Teeth Birds 20I Coverings Fishes 204 206 207 209 212 viii Longmans Object Lessons C. LESSONS ON ELEMENTARY BOTANY. PAGE PAGE Cotyledons 213 Roots . . 215 Stems . ... ... 218 Leaves 222 Flowers and Fertilization . . 223 Fruit and Seed 226 Flowerless Plants 23c NOTES OF A LESSON ON THE CAT 232 INDEX 235 LONGMANS' OBJECT LESSONS PART I HINTS ON PREPARING AND GIVING LESSONS SHOULD SCIENCE BE TAUGHT? Students of education who are engaged in the actual work of instruction are frequently forced to think how, but rarely „ . . why, any given subject should be taught. Every tions which teacher must himself answer the first question : the should in- fluence the second is generally answered for him. Authority or choice of subjects of custom decides that certain subjects shall be taught and that certain other subjects shall not be taught : hence there is no room for choice except among that class of subjects concerning which authority is silent and custom speaks with varying voice. That class at present often in- cludes science, and before we can decide whether science should be taught, we must examine the principles that ought to determine the admission of any subject into a well-con- sidered course of studies. .^ The first principle is practical value. School life is a pre- 2 Longmans Object Lessons \ paration for the wider life to follow, and it is the duty of a I teacher to provide his pupils, as faikas possible, with the knowl- I edge which they will require aft« they have passed from ^ , . under his care. If, for instance, they were all going to be physicians, it would ^je his duty to give them as much instruction in anatomy, philology, chemistry, and materia medica as they had time and capacity to receive. The same remark applies to every other calling. But, as a rule, the teacher does not know what are the occupations before his pupils, while he does know that these occupations are many and diverse, and that he has no time to teach even the rudi- ments of any of them. It, therefore, is his duty to prepare children, riot for one trade or profession, but for all ; it is his duty not to make them doctors or lawyers, shopkeepers or artisans, but to make them men and women with faculties well developed and minds well stored with information that can not fail to be of service in any walk of life. His aim must be the greatest usefulness to the greatest number. Conse- quently those subjects ought most frequently to appear in courses of study, a knowledge of which is most frequently required in practical affairs. Reading, writing, and arithmetic are taught to every pupil in every school, because every pupil after leaving school finds a knowledge of them essential. J The second principle that ought to regulate the admission of any subject into a course of study is educative value. The 2. Educa- muscles grow and are strengthened by use, and as tive value. -^q^V and the ordinary activities of life are likely to produce a disproportioned and partial development of the body by unduly exercising some of the muscles while leaving others unexercised, gymnastics have been invented. Now, the fact that most men go through life without being called upon to exhibit acrobatic skill is no argument against gymnastics. We practice them not because we think that some day we may Should Science be Taught f 3 be called upon to swing on a trapeze, vault over parallel bars, or handle dumb-bells and Indian clubs, but because we know that they make the body fitter for the performance of what- ever operations it may be required to undertake. What is true of the body is also true of the mind. The mental faculties grow and are strengthened by exercise, and we pursue certain studies not because we think we shall be called upon to apply them, but because we know that they make the mind fitter for the performance of whatever operation it may be required to undertake. Algebra and Euclid are cases in point. No one who knows these subjects would deny that they have immense practical value, but we do not teach them solely, or indeed mainly, because of that. Though we might be quite sure that none of our pupils would ever apply his knowledge of algebra or of Euclid, we should continue to teach both for the sake of the mental development that the study of them brings. Algebra trains the mind to deal with abstractions and generali- zations, and Euclid to make correct deductions from stated premises, and though skill in mathematics may to many per- sons be of little practical value, skill in abstract and deductive reasoning must be of great importance to everyone. The third principle that ought to regulate the admission of a subjec^nto a course of study is aesthetic enjoyment. Litera- re and art are taught not so much because of their !cunto a 3. Pleasurc.^^ . , , ^^-.ctical or educative value, as because they tend to refine and. elevate the mind and add largely to the innocent pleasures of life. Applying to a particular case the three general principles thus laid down, whit are the claims of science to a place in The lai every school curriculum? If based on only one of of science, the three, its claim deserves consideration ; if based " ''■ on two, it is very strong ; and if on the three, it is irresistible. The utility of science is now universally admitted. 4 Longmans' Object Lessons Science helps to satisfy the first and strongest demand of nature — the demand for self-preservation. Increased knowledge of the laws of sanitation, with increased obedience to them, has in the last half-century added ten years to the average length of human life, and has, at the same time, made life more enjoyable and more useful because more healthy. And the limit of improvement is far from being reached yet. Thousands of babies still die annually from their mothers' ignorance of infant digestion and the constituents of food, and thousands of men and women contract avoidable diseases from ignorance of hygienic laws. Besides preserving health and prolonging life science adds to our comforts and conveniences. Steam and electricity are only two of the forces that it has enlisted in our service, and yet, deprived of these two, existence to the modern man would hardly seem worth having. Science is, moreover, the foundation of every art and manufacture carried on among civilized people. If, therefore, any subject can claim to be taught in schools because of its utility, surely science can. The claim of science to be taught for the purpose of developing the faculties is also incontrovertible. Every physical 2. Educa- science begins with the careful and intelligent ob- tive yaiue. gervation of facts and then proceeds to classify and generalize ; hence the pursuit of it gives a keenness to the ■senses and a vigour to the reasoning powers which must be of immense value in any department of human activity. Each faculty trained by the study of science may perhaps be trained by the study of some other subject, but no other subject trains at once a// the faculties traiiied by science. The study of science also adds . to the pleasures of life. Where another person might see only a dull flat country and a soil as void of interest as of crops, one who knows 3. Pleasure. somethmg of botany and zoology sees open before him a fascinating page in the great book of nature. Every When should Science Teaching begin? 5 blade of grass, every tuft of moss, the butterfly that crosses his path, the lark that mounts aloft, is for him instinct with meaning and delight. A starry sky is to everyone a beautiful picture. To the astronomer it is that and much more. Every brilliant point is to him as the face of an old friend ; he knows its name and its history, and looks for its return at the appointed time. And so with every other science. We cannot study one which shall not add interest to every country walk, to every excursion on river, lake, or sea, even to every journey by rail. It was the loss of innocent pleasure, not of useful information, that Carlyle deplored when he said : ' For many years it has been one of my most constant regrets that no schoolmaster of niine had a knowledge of natural history, so far at least as to have taught me the grasses that grow by the wayside, and the little winged and wingless neighbours that are continually meeting me with a salutation which I cannot answer as things are. Why did not somebody teach me the constellations, too, and make me at home in the starry heavens which are always overhead, and which I don't half know to this day?' WHEN SHOULD SCIENCE TEACHING BEGIN? Assuming that science is to be taught to all, when should the teaching begin? What has already been said about the edu- Y cative value of the subject points to the answer. The children study promotes the growth and vigour of the facul- capable of ties employed in observation, classification, gener- the formal ... , . , . . , r ^ study of alization, and mductive reasomng ; but of these SC16I1CC the faculties employed in observation are most active in young children, the others being often either dormant or 6 ' Longmans^ Object Lessons altogether absent. • It is therefore obvious that a complete and rigid study of science is beyond the capacity of young children, and that such study should begin only when the powers of abstract thought are sufficiently developed. This they are be- lieved to be in ordinary cases at the age of twelve to fourteen, and to attempt the teaching of severe science before that age has been reached is to don the armour of Saul on the body of David. But it does not necessarily follow that no scientific teaching should be given before. It is true that all the requisite facul- ties are not present in young children; but those that are present should be trained from the first, and the training of the rest should begin as soon as they manifest themselves. The very baby in arms begins to observe. As soon as he has attained to speech, he is full of questions about the objects ceptive around him and the phenomena of daily life. If a^remani- ^^^ natural curiosity is wisely satisfied and directed, '^^d^V^w' ^ broad and deep foundation is already laid for be trained future scientific teaching ; but, should his curiosity be suppressed or left without guidance, the absence of a body of sound observation to form a basis for scientific teaching is only one, and that not the greatest, of the resulting evils. A greater evil is the undeveloped state of the perceptive faculties themselves. A professor of geology in one of the American Universities says : ' I feel daily that the efficiency of my work as a student and teacher of science is marred by the vice of early education, which repressed rather than developed whatever powers of observation nature had given. My profes- sional life has been a perpetual struggle to rid myself of some of the mental habitudes induced by an unnatural education. . . . And what I have felt in myself I have seen in my students. It is worse than making bricks without straw to teach natural gcience to college juniors and seniors in whom disuse has When should Science Teaching begin ? 7 wrought so complete an atrophy of the powers of observation that they hardly know that there is an external universe.' l^ This, then, is the answer to the question, 'At what age should the teaching of science begin?' The complete and . formal teaching of any science can begin only when should the powers of abstract thought have begun to manifest science teaching themselves — that is, only when the child has reached the age of twelve to fourteen ; but teaching calcu- lated to develop the faculties required for the study of science must begin even in the infant school. If there were no other argument in favour of beginning thus early, there is an incon- trovertible argument in the fact that the school education of the majority of our children ends before the time for the definite study of science has arrived, and that if they are not trained in the infant school and the lower classes of the primary school to perceive physical truths, and, in a measure, to reason from what they perceive, they will be forced to go through life without the help of intellectual implements and tools that might have been theirs. Courses of Object Lessons, arranged with some regard to y the laws of psychology, prepared with care and given with skill, Q, . by directing the attention of children towards tan- Lessons a gible things, by encouraging them first to observe, and pre- then to compare, and finally to classify and general- paration .... .,i ., ■for science ize, furnish, not indeed an equivalent for definite science teaching, but the best substitute possible in the case of those who leave school at an early age. Such Object Lessons are, moreover, the iest preparation for it, because they place the pupil in the right road and lead him some way along it. When he begins the study oi- science he has simply to go further and faster in the same direction — he has simply to make more minute observations, more comprehensive comparisons, more distinct classifications, and more sweeping generalizations. ^ Longmans Object Lessons SUBJECTS OF LESSONS In the planning of courses and in the preparation of the Principles lessons themselves two principles must be kept underlying courses. Steadily in view : — 1. The end to be aimed at must be clearly understood, and the courses so arranged that they shall lead up to that end. 2. The lessons must be adapted to the successive stages of mental growth through which the children pass. aimedat. ^ "^^^ ^"^^s to be aimed at are three : — 1. The cultivation of the perceptive powers. 2. The communication of useful knowledge. 3. The cultivation of the powers of generalization and of inductive reasoning. With the youngest children the first must be the end chiefly aimed at, with the eldest the third. The second should be kept in view in all the lessons, but should not be allowed to dominate any. The earliest lessons should be on the common objects and the common animals to be seen in the home, the school, Subjects the streets, and the fields. The children should Siouid be ^^ made by the use of their own senses, aided by chosen. judicious questions from the teacher, to perceive the forms and chief properties of the objects and the most striking characteristics of the animals. A little later there should be lessons on common natural phenomena, such .as clouds, mist, rain, snow, and thunder. Gradually the range of observation should be extended till it includes typical selec- tions from the animal, the vegetable, and the mineral worlds, and the simplest elements of physics and biology. Finally, Subjects of Lessons g Object Lessons should give way to definite lessons on those sciences towards which all the courses have been gradually tending. Having regard to the fact that the powers of children are constantly developing, it is obvious that several lessons may be given on the same subject at successive stages. Three lessons may, for example, be given on coal, the first dealing with its more obvious properties, the second with the min- ing, and the third with the origin of it. In looking over actual courses of Object Lessons one is often struck by the fact that they include lessons which must be given without any appeal to the senses, and which, there- Subjects fore, cannot, properly speaking, be Object Lessons should not ^^ ^'^- ^ have seen ' included lessons on Miltiades, be chosen. Alexander the Great, Hannibal, and Julius Csesar ; on Martin Luther, Mohammed, Frederick the Great, and Napoleon ; on Scott's Novels and Shakespeare's Plays ; on Drake, Cook, Franklin, and Livingstone ; on Arctic and on African Exploration ; on Honesty, Truthfulness, Temperance, and Kindness ; on Thrift, Wages, Strikes, Supply and De- mand, Money, Rent, Taxes, Trial by Jury, and the Making of Laws. No one will deny the extreme desirabiUty of giving les- sons on most of these subjects ; all that I contend for is that they should not be included in a course of Object Lessons. Arrange- Granted that every subject chosen may rightly lesson's^in ^^ included, the arrangement of the subjects into courses. series remains. The three chief points to be con- sidered here are : — I I. That each lesson shall be placed in that part of the series where it shall be most suited to the stage of mental 1 I hope that the fact of its having been my duty to hear and criticise the lessons of hundreds of teachers will be allowed to excuse occasional reference to what has come under my own notice. lO Longmans' Object Lessons development reached by the class. An observation lesson on the properties of chalk, for example, would be too simple for children of eleven or twelve, while one on the composition and origin of chalk would be too difficult for children of seven or eight. The first would convey no information because most of the facts would be fanaliar, and the second would convey little because most of them would be unintelligible. The first would make no demands, and the second would make impos- sible demands upon the powers of the children ; neither, there- fore, would interest or instruct ; neither would possess any value, practical or educative. [ 2. That the lessons shall follow one another in logical order and coherence. ) All the information that is necessary to a com- plete understanding of the second should be given in the first ; of the third in the first and second. A lesson on the composi- tion of air, for example, should follow, not precede, lessons on the constituent gases. 3.\ That the lessons shall lead directly to the end proposed. It has already been shown that Object Lessons form the best preparation for definite science teaching, and both in the choice and the arrangement of the subjects the particular science or sciences to be taught ought always to be kept in view. MATTER OF LESSONS The subject of the lesson being decided upon, the teacher Matter of ^as next to decide what he shall say about it. It should vary would be as impossible to teach as it would be *'* unwise to try to teach all the facts available, and a selection has to be made varying with — (i) The age of children, (2) What they already know of the subject, (3) The time allotted to the lesson. Matter of Lessons 1 1 1. If the children are young, the teacher will dwell chiefly upon the simple facts which they can find out by the exercise - Age of ^^ '^\'^^vc senses and the simple inferences which they children, ^^^ ^g jg^ (-^ make, while he will avoid technical terms, difiScult generalizations, and complicated explanations. If, for instance, a lesson were to be given to children of seven or eight on the parts of a flower, the teacher would show the parts in different specimens till the children could recog- nize them under their varying forms, but he would say nothing of the functions of the parts or of their botanical names. On the other hand, if a lesson on the same subject were given to children of eleven or twelve, great stress would be laid on the functions, and the botanical names would be introduced. Similarly, if the lesson were on a manufacture, the teacher would with the younger children demonstrate the essential qualities of the raw material, and give only the broadest out- line of the successive processes ; whereas with the elder children he would almost assume an acquaintance with the qualities, and give pretty full details of the processes. 2. If what the children have already learned is not taken into account in the choice of matter, their time may 2. Their ■' previous be wasted in an attempt to teach them what they ' know, or the foundations laid in previous lessons may be ignored, and the old instruction may not be made to serve as a basis for the new. 3. When the teacher in preparing a lesson does not bear in mind the number of minutes at his disposal he may provide 3. Length '•°° ''''•'^ matter or too much. If there is too little, of lesson, jjg jg jj^jgiy jq ^gg \3xa repetitions in order to occupy the allotted period. If, on the_ other hand, there is too much, he is likely to hurry through it, teaching nothing effectively, or to teach the first part effectively and to omit the last part alto- gether. In the first case the lesson is vague, in the second 12 Longmans' Object Lessons unsymmetrical ; in either case no foundations are laid for the next lesson in the series. With regard to the choice of matter a word of caution may, ' perhaps, be necessary. An Object Lesson is a lesson on objects. Things, not "ot on language. Incidentally and indirectly it may I words. teach new words or give clearer notions of the mean- ings of old ones, but when it is deliberately made the medium of instruction in language its purpose is entirely misunderstood. Perhaps the greatest and most common mistake in this respect is unintentional. I have heard a teacher who had to give a lesson on Leather, and who fully believed that he was doing all that could be expected of him, spend more than half his time, not in trying to show that the substance is odorous, flexible, opaque, &c., but in trying to explain the terms odorous, flexible, opaque, &c. A satisfactory lesson might be given on the Prop- erties of Leather by first demonstrating how many of them are found in the original hide and how many are imparted in the manufacture, and then by explaining how the various uses of leather depend upon the possession of them ; but that would be a lesson on the properties, not on the meaning of certain hard words employed to denote them. The next step after the selection of the matter is the arrange- ment of it ; but here no very definite directions can be given, because an arrangement which is bad in one set of Arrange- ment of circumstances may be defensible in another. To matter. begin a first lesson on the Cat, -for example, by say- ing that the anirhal belongs to the sub-kingdom vertebrata, to the class mammalia, the order carnivora, and the family felidse would betray gross lack of judgment and gross ignorance or disregard of psychology, whereas to begin thus might be justi- fiable after a large number of lessons had been given on typical animals and on the principles of classification. I . The first general direction with regard to arrangement is Matter of Lessons 13 that the facts should be presented in a natural order. The teacher should consider what are the processes by which chil- I. Should dren, if left to themselves, acquire knowledge, and be natural, j^g should imitate those processes as far as may be consistent with obtaining more definite results in a briefer period. If, for instance, a lesson had to be given on Lakes, Rivers, and Canals, the teacher should remember that children at first note only the presence of water. Then they note the differences between the three bodies — the water of a river moves, while that of a canal and of a lake is (practically) at rest ; a lake is broad in proportion to its length, while a river and a canal are long in proportion to their breadth ; a river winds, while a canal is almost straight ; a lake and a river are natural, while a canal is artificial. Finally, they learn, by wider observation, or the information of their seniors, that the lake, river, and canal familiar to them are typical, and they are then ready for classifications and definitions. To begin, therefore, with classifications and definitions, as young teachers, copying the method adopted in text-books (perhaps for convenience of reference) often begin, is to reverse the order of nature. 2. That part of the subject which most readily connects itself with the previous knowledge of the children should be placed first. New ideas, when not arising from the knowledge presentation of new objects, must be formed by the should be joined to modification of ideas already possessed. The idea, for example, which a child who has not seen a lake forms of it is a modification of his idea of a pond. If a new topic introduced is not brought into relation with what has gone before it must fall for want of support. Futhermore, association is the most valuable principle in mnemonics, and the connecting of the new idea with the old is a great help to the remembering of both. 3. A mental survey of all the information to be conveyed 14 Longmans' Object Lessons will sometimes show that if certain facts were presented first all the rest would follow naturally in a train of inductive reasoning. If a lesson on the Swallow, for instance, began with 3. Eliciting. i 1 1 1 • i the food, the teacher could make the children infer that the bird can be with us in summer only, that it must live chiefly on the wing, and that its structure must, therefore, be what it is. 4. There should be no attempt at a uniform arrangement of the matter. Young teachers have a tendency to stereotype. I have seen a score of lessons on the same subject 4. Arrange- -' ment arranged exactly alike. They all began with an should not jo be stereo- 'Introduction,' proceeded to 'Properties,' and (after intervening heads) ended with 'Uses.' A formal introduction is sometimes useful and sometimes necessary. It is useful when the teacher is skilful enough by means of it to awaken interest in what is coming. It is necessary when a reference to preceding lessons forms the basis of the teaching about to be given. In all other cases it may be omitted with advantage. ' Properties,' too, may be omitted when they are obvious, when the children are familiar with them already, or when they have no bearing on what is to follow. The same remarks apply to 'Uses,' and, as a general rule, it is bad to separate 'Properties' and 'Uses,' for the second depend upon the first. NOTES OF LESSONS In school work, as in all other work, forethought and labour are the price of success, and a teacher who tries to give a The need lesson without adequate preparation courts failure, for notes, jj jg j^^j enough for him to have a general or even a minute knowledge of his subject. He must consider what are the facts to which he will draw attention, which of these he Notes of Lessons 15 must tell and which he can elicit, what is the best order for presenting them, what illustrations will throw most light upon them, and what exercises will most deeply impress them upon the minds of his pupils ; and experience has shown the advan- tage of noting down these points. The fulness of a teacher's notes of a lesson will depend largely upon whether they are meant for his own use alone or Full or for the inspection of another. If for his own use brief notes, ^lone, they will, so long as he is dealing with a. familiar subject, give only the heads of the matter, and brief hints of the methods and illustrations. When the subject is unfamiliar the matter will be given much more fully. Pupil teachers in training colleges have very often to write notes, not for their own use, but to show a critic how Full notes. , , ■ they would give a set lesson. In these cases the notes must be self-explanatory, and indicate clearly both what would be taught and how it is proposed to teach it. Granting that the execution of the lesson is equal to its conception, these full notes would give a reader almost as good an opportunity as a hearer would have had of estimating the skill of the teacher, but this implies that they should, in addition to pre- senting a clear outline of the matter, show the method with considerable fulness. Such meagre directions as 'Elicit,' 'Deduce,' 'Draw from children,' 'Get this from class by ques- tioning,' are useless, because exactly how the teacher is going to elicit, deduce, draw from the children, or get from the class by questioning is just what one wants to know. A minute description of the process might be tedious, but an outline of it should be given sufficiently full to convey clear notions to any- one who has the technical knowledge necessary to the under- standing of it. Notes intended for inspection by others than the writer should be set forth in one of two forms. Either the hints os 1 6 Longmans^ Object Lessons method should be intermingled with the matter, as in the les- Form of s°"s given in this book, or the matter and method the notes, should be kept distinct, as in the lesson on the Cat given in the Appendix (p. 233). Each form has some advan- tages to recommend it, though it matters little which is adopted. However carefully notes may be prepared, they are not necessarily to be followed rigidly in the giving of the lesson. Deviations Notes are made for the teacher, not the teacher for from notes. ^^ notes, and if, in front of his class, he discovers that the children have a greater or smaller knowledge of the subject than he gave them credit for, or that he has misjudged the difficulty of teaching any part, he should, as the lesson pro- ceeds, adapt himself to the unexpected conditions. To do otherwise would be to pay tithe of mint and anise and cum- min, but to neglect the weightier matters of the law. ILLUSTRATIONS A teacher's character may, to a great extent, be inferred from the way in which he illustrates his lessons. If he lacks iilustra- industry, he will either not illustrate them at all, or index^io ^^ ^'"^ illustrate them with whatever chances to be character, available at the moment. If he lacks foresight, he will fail to provide some illustration that is absolutely necessary, or the illustrations that he provides will prove ineffective because some essential detail has been overlooked. If he lacks originality and ingenuity, his illustrations will be far- fetched, or they will be spiritless copies of something that he has seen or heard of. On the other hand, the teacher who is diligent, prescient, and ingenious foresees and provides all the illustrations needful, adapts to his needs whatever may be within reach, and ensures success by a careful attention to details. Illustrations if It is hardly possible to lay too much stress on the impor- tance of fully illustrating Object Lessons ; for an Object Lesson impor- that is not fully illustrated is a contradiction in Inusta- terms and a foredoomed failure. The primary tions. purpose of an Object Lesson is the cultivation of the perceptive powers, and this purpose is entirely defeated if the teacher does not offer materials for the exercise of the children's senses. An Object Lesson without illustrations is hke a swimming lesson without water or a singing lesson with- out sound. The illustrations are not an ornamental fringe ; they are the very warp and woof. Their function is not, like the pictures in our novels, to add to the interest and clearness of the story ; rather, like the pictures of the ancient Mexicans, they are the story itself. Where available, the best possible illustrations for an Object Lesson are actual objects. Pictures are worth having when Kinds of nothing better can be had, but the illustrative value illustra- Qf jijg ygj-y ]-,gg(. pjcturcs is small compared with that I. Actual of the things themselves. That is especially so in o jecs. those very cases in which inexperienced teachers most frequently use pictures — that is, when the lessons are about animals. A picture of a cat, for instance, will not show the roughness of the tongue or its spoon-like action when lapping; it will not show the pads- beneath the feet, or the projection and retraction of the claws ; it will not show the sheaths that protect the claws, the arrangement of the fur, or the effect of Hght upon the pupils ; all of which can be abun- dantly and easily demonstrated from a living specimen. Simi- larly, a picture of a fish would show the shape and position of gills and fins ; but a gold-fish in a bowl, or even a stickleback in a jam-bottle, would show these even better, and would, in addition, show gills and fins at work. In order to illustrate lessons on animals in the way suggested, 1 8 Longmans Object Lessons there is no need for the teacher to turn his school or his home into a menagerie. Many children keep pets, and Animals. would be pleased if the teacher were to borrow them for the purposes of a lesson. I have seen lessons on the Dog, the Cat, the Hen, the Rabbit, the Pigeon, and the Lizard illus- trated with animals thus borrowed, and the most delighted member of a delighted class was the proud owner, who was allowed to stand in front and look after his own pet. Many animals not usually kept as pets may also be obtained with a little forethought. I have seen lessons on Rats and Mice, Snails and Slugs, the Frog, the Swallow, the Sparrow, and the Bat illustrated with living specimens caught by the teacher or his friends. And animals that may be difficult to obtain alive may often be easy to obtain dead. I have seen dead Her- rings, Mackerel, Crabs, Lobsters, and Oysters used with admi- rable effect ; indeed, they were in some respects more useful dead than alive, for, as they were dead, the teacher was able to dissect them, and thus show their internal as well as their exter- nal structure. I have also seen lessons on animals illustrated with specimens stuffed or otherwise preserved. I remember, in particular, a most interesting lesson on the Crocodile illus- trated with a small stuffed specimen which the teacher had borrowed from a friend who had brought it home from Egypt. I also remember effective lessons on Butterflies, Beetles, Hum- ming-birds, and Serpents illustrated with preserved specimens. It is obvious that there are many natural history lessons which cannot be illustrated with living or dead specimens. Parts of Some animals are too big, some are dangerous or animals. disagreeable to handle, and many are impossible to procure; and in these cases the teacher is compelled to fall back upon the best available substitutes. Where a whole ani- mal cannot be used or cannot be procured, parts are useful, and with a little luck and some thought the school museum Illustrations 19 may be well stocked with these. The teacher's own dinners will furnish the shoulder-blade of a sheep, the head and limbs of a rabbit or hare, the heads, feet, and typical feathers of hens, ducks, geese, and turkeys, while, if he keeps his eyes open and has ordinary good fortune, he can pick up and procure the skulls or parts of the skulls of many common animals, and the heads of many common birds. Aided by these specimens, the teacher can give many valuable lessons on structure. Thus he can give lessons on bones, teeth, and feet generally ; he can show the relation between the teeth and food of various mam- mals ; and he can connect the beaks and feet of birds with their food and habits. Lessons on indigenous plants, too, should be illustrated with the actual things, and here, happily, there is no difficulty about obtaining specimens, as the build of roots, stems, bark, fibre, leaves, wood, seeds, and fruit can be abundantly demonstrated from material growing in profusion everywhere. Even in the case of foreign plants, the teacher is not entirely dependent upon pictures. Tea-leaves, for example, can be taken from the pot and pasted on white card ; tobacco- leaves, cocoa and coffee berries, ears of corn, cork bark, and many other vegetable substances can be obtained at the shops. Lessons on manufactures may often be illustrated with actual things. If the teacher himself lives, or if he has a friend Manufac- I'ving, in the district where any manufacture is carried '"'^^^- on, he will be able to get specimens showing every stage from the raw material up to the manufactured article. If the school museum does not show the processes through which wool, cotton, flax, iron, pens, pins, cork, and sundry other products pass, the teacher must be wanting in energy or luck. It greatly adds to the value of a lesson on a manufacture for the teacher to be able to imitate, no matter how roughly. 20 Longmans* Object Lessons the actions that he is describing. His descriptions will gain much in interest and in clearness, and will be far better re- membered than if he trusted to words alone. I have ProcGsscs seen the making of soap, paper, bricks, and pottery illustrated in this way. I have seen a hat pulled to pieces and re-made ; a lock, a knife, and a clock put together, and a book bound in the presence of a class. Whatever may be the subject' of the lesson, and whatever may be the specimens used to illustrate it, the children must see them, and, where the nature of the specimens Illustra- tions must permits, handle them also. An object held before the class appeals to only one sense, and, if small, appeals imperfectly to that. A single piece of money is not of much use to illustrate a lesson on coins ; but if a coin were given out to every child the various stages in the minting would become quite clear. Lessons on leaves, flowers, the parts of a flower, seeds, and many other subjects should be similarly illustrated by letting every child have specimens — indeed, could not be properly illustrated in any other way. In speaking of illustrating by objects, I have assumed that the school has a museum. This need cost very little, because School when a good dust-tight case with a glass front has museum. been provided, the expense is practically over. Many useful things the teacher can furnish from his home stores ; many animal and vegetable products can be obtained for the trouble of picking up or asking for ; children and friends will become large contributors when once they are made to under- stand that illustrative objects and not curiosities are wanted ; and most of the leading manufacturers, with a courtesy which cannot be too gratefully acknowledged, are ready to furnish samples of their wares in every stage of production. In ar- ranging his series of lessons the teacher will have the museum in mind, and now and then set a subject, not because it is Illustrations 2 1 essential that it should have a place in the series so much as because he has at hand abundant means of illustration. The most effective illustration of a lesson is the actual thing spoken of; the least effective is a picture of it. Between the two come models, which, being only imitations, are 2.' Models. rr ■ II- 1 • 1 . • not SO effective as real objects ; but which, being capable of examination from all sides, are more effective than pictures. In every good Kindergarten and infant school toys and other models are much used, but they are rarely seen in other grades. This is a pity, because even a rough model will add wonderfully to the clearness and interest of a lesson. A lesson on the Mountains and Rivers of a country, for in- stance, almost gives itself when the contours are shown in clay or plaster. No picture and no description can make the children understand the working of the common pump half so well or half so quickly as a model which can be constructed in half an hour out of glass tubing, and I have seen the work- ing and internal structure of a steam-engine illustrated with a sectional model in cardboard, which did not take many minutes to prepare. In the best Continental schools lessons in natural history are always illustrated with life-like models, though they are rare in England and America. Though pictures are the least effective illustrations, they are by no means to be despised, and, where nothing better can be had, they are indispensable. The pictures 3. Pictures m the market are often excellently adapted for their purpose, but the supply is not yet adequate. The characteristics of a good picture are three : — I. It should be large enough to be seen by a whole class at once. If a small picture is placed in front, only a few of Should be the children can see it properly, and if it is carried large; through the class, little good is done, because a clear conception cannot be formed from a brief glance. 22 Longmans Object Lessons 2. A picture should be artistic, though artistic excellence should not be its chief or only recommendation. Its primary Should be purpose is to illustrate lessons, and if it is not suitable artistic; j-qj. jj^jg^ artistic merit will be an insufficient com- pensation. Some publishers, overlooking this elementary fact, have issued beautiful pictures which are poor illustrations. There is, for example, a series of heads of animals admirably drawn and printed, and well adapted for copies, but almost useless as illustrations ; for how can a teacher give a complete lesson on an animal when all that he can show is a represen- tation of its head ? 3. Pictures of native subjects should be of native origin. It matters little to a teacher, as teacher, whether his picture of a lion was produced in London, Paris, Berlin, or Should be ' ) ) > of native Vienna, but it matters very much where his picture origin. . , , ^^ , , of a cow is produced. He cannot and does not want to show every kind of cow; his purpose is best served by showing a typical native cow, but if he has a foreign picture he may be showing only a typical French or German cow. The same remark applies to all domestic animals and to all familiar scenes, and yet one often sees, especially in infant schools, pictures of horses, cows, sheep, and dogs which are not exactly like anything that has ever come under the obser- vation of the children — farmers with caps and curved pipes, carpenters with blouses and wooden shoes, and washerwomen with battoirs. The pictures, as pictures, may be excellent (though in many cases they are very much the reverse) ; but let their artistic merit be what it will, they are not of much use out of the countries in which they were produced, because elsewhere they offer few points of contact with the daily life of the children. A drawing on the blackboard may often be used 4. Black- " . . . ■' board instead of or with printed pictures. Such a drawing drawings. 1 j ^ has several advantages. Illustrations 23 1 . It awakens interest by, being produced before the class. 2. It assists the attention and the memory by presenting only those details that the teacher wishes to emphasize. 3. It is always available. 4. It can be more easily copied by the children than an elaborate printed picture, and the act of copying will help to fix the lesson in the mind. The blackboard drawing can be made to supplement the printed picture — 1. By showing the inside and the ' other side.' 2. By showing on a large scale parts of the picture too small to be seen by the whole class. 3. By showing successive stages in the growth or develop- ment of the object portrayed. The use of coloured crayons will make blackboard pictures much more effective and much more interesting. Every lesson that deals with even the elements of physical science should be amply illustrated with experiments. Children 5. Experi- must receive scientific facts, not on the authority of ments their teacher, but on the authority of their own senses, and if a direct appeal is not made to the senses, the lesson had better not be given. As has already been said, the object of science teaching is to foster the habit of observation and to store the mind with useful knowledge ; and how can observation be fostered when there is nothing but a teacher and a blackboard for it to be exercised on, and how can the mind be stored with useful knowledge when words are made to take the place of things ? I have seen a lesson on the Composition of Air given without a single experiment ; for any real good it did it might as well have been given in Greek. If the teacher had prepared jars of oxygen, nitrogen, and carbonic acid he could have made the children see the properties of each gas ; 24 Longmans' Object Lessons he could have demonstrated that substances burn very rapidly in oxygen, and will not burn at all in nitrogen ; he could have elicited the necessity for ' diluting ' oxygen with nitrogen ; he could have shown the proportion of the two gases in the air, and made clear that carbonic acid is a product of combustion (and of respiration) . All experiments should be carefully prepared, and delicate or difficult experiments rehearsed. Failure is often due to the Should be neglect of some apparently trivial detail. I have prepared ggg„ ^ lesson on Oxygen entirely miss its mark be- cause the teacher had forgotten to provide matches to light the substances that he had intended to burn in the gas. Similarly, I have seen a teacher who had to give a lesson on Magnets spend five minutes making in the presence of the class prepara- tions which he should have made beforehand, and, after all, break down because he had no magnet. Teachers should con- sider that the failure of an experiment is a serious matter, because it may mean the failure of the lesson, and it must mean waste of time and loss of esteem. To prepare and to perform experiments is not all. I have known teachers prepare experiments carefully and perform And ex- them skilfully and yet do little good with them, for plained. ^^ experiment is not necessarily an illustration. Every experiment exemplifies some principle, but it does not illustrate the lesson unless the teacher makes perfectly clear what the principle is, and how the experiment exemplifies it. It is not enough, for instance, if a teacher wants to show the relative proportions of oxygen and nitrogen in the air, for him to say, ' A fifth of the atmosphere is oxygen and the re- mainder chiefly nitrogen,' and then perform the usual experi- ment of burning phosphorus under a bell-jar placed in water. He should, first of all, make clear, by a series of questions, that the jar, at the beginning, contains only air — that is, contains Language 25 only oxygen and nitrogen. Then he should similarly make clear that the burning of the phosphorus exhausts the oxygen ; that the phosphorus goes out before the whole of it is consumed because there is no more oxygen ; that the water rises to take the place of the gas used up, and that therefore the height of the water is the measure of the oxygen and the space above is filled with nitrogen. So treated, the experiment would be an illustration as well as an experiment. Young teachers sometimes seem to think that experiments are introduced merely to interest and amuse. I saw one „ teacher who had to give a lesson on the Pressure of Experi- ° ments are the Air lecture for half an hour, and then spend ten not for '^ amuse- minutes over a few poor experiments ; and another, who had to give a lesson on Fusible Substances, perform all his experiments together at the end — apparently as an after-thought. Experiments do interest and amuse, and if they did nothing else they would be worth having; but, properly used, they do far more. They do even more than make the children understand — they make them discover. They should, therefore, be the foundation of the teaching, not an ornamental addition. The same remark applies to other illustrations. LANGUAGE In treating of the selection of matter, I referred to the abuse of technical terms. Inexperienced teachers seem to Technical think that words of learned length and thundering terms. sound are a necessary part of every Object Lesson. They introduce such words freely, strive hard to explain them, and delude themselves into a belief that they are teaching science when they are not even teaching the terminology of 26 Longmans' Object Lessons science, for the only way in which we can make children really understand words is to make them familiar with the things to which the words apply. I do not say that technical terms should never be employed, but I do say that they should be employed sparingly in Object Lessons. The proper time for them is when the definite study of science is undertaken ; before that they should be employed only when their use obviates long circumlocutions, or when there are no short and simple names for the things denoted. To speak, as I heard a teacher speak in a lesson to young children on the Spider, of palpi and a cephalo-thorax is worse than useless — it is giving a stone for bread. A teacher's language may be entirely free from technical terms, and yet be almost unintelligible from its 'bookishness.' 'Bookish- Only a long experience of children enables one to "^^^" realize how narrow are the limits of their vocabu- lary. The limits vary, of course, with the character of the homes ; but, even when the parents are educated, young chil- dren have not a large stock of words, whereas when the parents are uneducated the stock is very small indeed, and simplicity becomes doubly a duty. It has been stated that an illiterate hind can express the whole of what are called his ideas with 400 words. This number is probably under-estimated,' but 1 An American writer, after a careful inquiry into the number of words used by various classes, comes to the following conclusions : — • ' Every well-read man of fair ability will be able to define or understand 20,000 or 25,000 primitives and principal derivative words. 'The same man, in his conversation and writing, will use not less than 6,000 or 7,000 words. Ifhe.be a literary man he will command 2,000 or 3,000 more. ' Common people use from 2,000 to 4,000 words, according to their general intelligence and conversational power. ' An " illiterate man" (one who cannot read) will use from 1,500 to 2,500 words. ' A person who has not at command at least 1,000 words is an ignoramus, and will find difficulty in expressing his thoughts, if, indeed, he have any to express.' Questions 27 there can be no doubt that uneducated people know the meanings of comparatively few words, and that their children know the meanings of still fewer. A teacher is, therefore, not likely to be understood when he speaks to such children of ' subjecting butter to the influence of heat,' of ' bringing a flame to bear on a fusible metal,' or of a reptile's tongue having ' an adhesive substance at its extremity,' and it should never be forgotten that if our pupils have to think about our words they cannot be thinking about our thoughts. A teacher's language should be transparent — not like a stained-glass window, which may in itself be worth study, but which obscures or excludes the surrounding world. A teacher should aim at speaking so as to be understood by all his pupils — if he does not want to be understood, why should he speak ? — but to make his meaning clear Purity. he should never resort to mean colloquialisms, to slang, or to provincialisms. His language should be a model of purity as well as of simplicity, though it would be pedantry to set up as high a standard of style for speaking as for writing. QUESTIONS A lecture, differs from a lesson. Both the lecturer and the teacher strive to secure attention by the presentation of inter- esting facts or the interesting presentation of facts ; and teach- but the lecturer looks upon his audience as a whole, ing. while the teacher looks upon his as units. The lecturer does not hold himself responsible for all his hearers understanding or for any of them remembering what he says, but the teacher considers it his duty to make each hearer understand and remember. The lecturer makes statements. 28 Longmans' Object Lessons while the teacher mixes questions with statements ; and what is meant for a lesson often is only a lecture, because few ques- tions are asked. A teacher asks questions — Purposes of • ^ question- i. To find out what the children know, so that he ing: — 1. To may avoid waste of time in trying to teach what has vious been already learned, and may ascertain what is the now e ge. fQyjjjjg^jJQjj qjj ^hjch he Can build. 2. To convince children of their ignorance, and thus awaken in them a desire for knowledge. In nearly every class there are a few children who have too high an opinion of 2. To con- vince of their own attainments, and who, believing that the teacher has nothing new to tell them, are little disposed to listen. A few searching questions will, without destroying necessary self-respect and self-confidence, show these that they have yet much to learn. 3. A teacher sometimes asks questions to secure attention. When children allow their minds to wander, nothing 3. To secure at- SO promptly and thoroughly recalls them to the tention. . ■ , 1 ,, - 1 busmess in hand as a well-aimed question. 4. A teacher also asks questions to direct and encourage thought. It is important that children should be made to remember, still more important that they should be 4. To direct made to understand, and most important of all that they should be made to think. The second includes the first, because the better we understand a thing the easier we shall remember it ; and the third includes the first and second, because if, with or without guidanfce, we think a thing out for ourselves, we shall both understand and remember it. It may be useful to remember such simple formulse as j' •= \ft'^ or sin.^A -(-cos.^A= i ; we are the more likely to remember them the better we understand what they mean and how they are applied ; we are certain to remember and understand them Questions 29 if we can go through the processes by which they are arrived at. The opportunities which different subjects of study afford for the cultivation of the thinking powers vary greatly ; the degree to which different teachers avail themselves- of those opportunities also varies greatly ; and it may be safely asserted that that subject possesses the highest educative value which affords most opportunities for quickening thought, and that that teacher is the best educator who most fully avails himself of the opportunities afforded. Whatever may be the purpose for which questions are asked, certain general rules apply to them. 1. They should be clearly and concisely worded. Before beginning to speak, the teacher should form a perfectly definite idea of what he wants to ask, and then ask it in such Rules for questions : a way that the pupils shall also form perfectly definite be clearly ideas. How could children be expected to follow the following question with which I heard a teacher introduce a lesson on Frogs : ' If any of you boys were to go into the country in the spring-time in the commencement of the year, and you go hear a stream in the country, in some parts you will almost be sure to see a lot of them (little things) jumping about and in the grass. What would they be ? ' What has been said generally about the language of lessons of course applies to the language of questions. 'What does a plant derive its life from?' is a concise question, perfectly clear — to those who understand it — but asked, as it was, to children of eight, it was unintelligible. 2. Questions sholild be definite enough to call forth the answer desired. 'Why is this lamp burning?' 'What do we 2. Should always find in the school-room in the day-time ? ' be definite. < -y^rhat are we always doing?' are types of questions likely to lead to much waste of time, because the teacher may get twenty correct answers before he gets that which he wants. 30 Longmans' Object Lrssons 3. It follows that questions should admit of only one correct answer. Such a question as ' What do you notice about this ? ' 3. Should (some object presented to the class) may appear oniv'one justifiable, nay commendable, because it requires an answer. exercise of the children's own powers of observation, but there is a danger of its bringing answers which are irrele- vant, or which cannot be used at that stage of the lesson. ' What do you notice about its, weight, shape, colour, head, eyes, teeth, fur, &c.?' would have all the merits of the vaguer question and be free from its defect. 4. Questions which admit of only two correct answers should not be asked. If I ask, ' Is this metal hard or soft ? ' 4. Should 'Did Richard follow the advice of his father?' one of onhMwo °^ '^^ '"'^ possible answers is, as a matter of chances, answers. as likely to be correct as the other, and there is little incentive for children to think when the probability is so small of their being wrong if they do not think. Besides, when the wrong answer has been rejected, the right one can be given without any thought whatever. 5. It follows that no question which would encourage guess- ing should be asked. Guessing is encouraged directly by such 5. Should questions as, ' What do you suppose the size of a coirage cotton plant is?' 'Who thinks that it is six feet guessing. jjjgj^ p ' ' Hands up, boys, who think cork will burn ; ' and it is encouraged indirectly by asking questions which the chil- dren cannot reasonably be expected to answer, such as, ' What is put on the land to make it rich again after the tobacco crop ? 6. A question should not, as a rule, be asked on the sub- 6. Should stance of a statement immediately after the statement asked im- ^^^ ^^^en made. If children are told, ' Bricks are after'state- ™3-de of clay,' and at once asked, 'AVhat are bricks ment. made of? ' they can give the right reply without thought. A question immediately after a statement may be Questions 3 1 necessary when a child has to be convicted of inattention, or when the subject is so very difficult that the teacher must malce sure at every step that the children are following him. 7. Questions should be well distributed. Some teachers confine their questions to the children immediately be well dis- in front of them, some to the bright, and some to tributed. the dull. 8. Questions should not be repeated, as repeti- not be tion on the part of the teacher invites inattention on repeated. the part of the scholar. A statement ending with an ellipsis to be filled up is a form of question requiring the least possible exertion from the pupils, and is, therefore, a form which should be employed Ellipses. only when there are sufficient reasons for making the work specially easy. The ellipsis, moreover, requires careful treatment. There ought to be but one way of filling up the blank correctly, and to find that way ought to require thought. ' Wheat grows in . . . ,' ' The motion of the earth on its axis causes day and . . . ,' and ' The molecules are kept together by the force of co- . . . ,' are all examples of bad ellipsis ; the first because the most thoughtful pupil might feel some doubt about the word desired, the second and third because the most thoughtless could feel no doubt whatever. Some attention should be paid to the wording of the answers as well as of the questions. Answers that are too brief Wording should never be accepted, even though correct in all of answers, jjut form. In the best Continental schools complete sentences are jequired in replies. This is a most valuable preparation for written composition, and though it may be pedantic to insist upon complete sentences always, there is no pedantry in objecting to such highly elliptical answers as the following : • What happened to the wax when I held it above the flame ? ' [Liquid.] ' What is the meaning of evergreen I ' [Always.] 32 Longmans' Object Lessons An Ungrammatical answer should never be accepted. Cor- rectness of speech is much more a matter of habit than of rules. The children of educated parents speak cor- Urgram- maticai rectly before ever hearing of grammar, whereas it is not rare to hear children who have been taught to parse and analyze very well speaking incorrectly. Every opportunity for assisting the formation of a good habit should therefore be seized, and an ungracnmatical answer is perhaps the opportunity which occurs oftenest. Suppose such an answer as ' They was too old ' to be correct in substance. The teacher should explain that it was right in fact, but wrong in form. The child who gave it might then detect the error ; if not, the teacher might proceed, ' You said, " They was too old ; " what ought you to have said?' There would have been no men- tion of grammar, and yet a valuable little lesson in grammar would have been given, for ' a child shall take more profit of two faults gently warned of than of four things rightly hit.' ^ The elder pupils could be made to see why the wording of an answer is wrong, but the teacher should not be tempted into digressions. He might make a note of the error, and use it as a text for the next grammar or composition lesson. TELLING AND ELICITING Jacotot, who maintained that a teacher should tell his pupils nothing, would be surprised and disappointed could he see how many teachers of the present day act as if it Jacotot. were their duty to tell their pupils everything. The precept of Jacotot was not altogether reasonable, and the prac- tice of the teachers to whom I have referred is not altogether 1 Roger Ascham, Telling and Eliciting 33 unreasonable. He forgot that we have to inform as well as educate ; they forget that we have to educate as well as inform. If children acquire only such knowledge as they can discover, or be made to discover, for themselves, they must remain ignorant of very many things that it is necessary and useful for them to know ; and they cannot enter into possession of the rich heritage of wisdom and experience bequeathed to them by the past, because if it is wrong for them to learn from a teacher it must also be wrong for them to learn from books. On the other hand, telling children too much allows their faculties to lie fallow, and their capability and god-like reason to fust in them unused. Jacotot's precept must be modified before it can command ^universal acceptance : A teacher should tell his pupils nothing ' Too much that he can make them find out for themselves in telling. school without waste of time. Many things — all historical and most geographical facts, for instance — they must learn from books, which is only another form of telling ; still there can be no doubt that children are told much that they ought not to be. Their memories are stored, instead of their faculties being developed. They are exhorted to open their mouths and shut their eyes and see what good things the gods will send them, instead of being made to earn the good things by their own exertions. The innumerable illustrations that might be given of needless telling divide themselves into two classes. Teachers tell what lllustra- children could find out by the exercise either of '°"^" their own senses or of their own reasoning powers. A teacher giving a lesson on Tobacco will tell his pupils that snuff is a fine brown powder, when, actually having some snuff, he could make them describe its qualities, presuming that they are worth' dwelling upon ; or, giving a lesson on a Coin, he will first tell them that it is composed of certain metals, and then 34 Longmans' Object Lessons tell that these metals are melted and mixed, when he could have made them infer the second fact from the iirst. In dealing with the arrangement of the matter of a lesson, I spoke of the possibiUty of starting with one fact and then making children infer other facts from it. When, Eliciting. , , , ,• t , for example, a teacher has shown a map of the eleva- tions of the United States he can elicit why the rivers are found where they are ; why certain slopes are well watered ; and why the Great Plateau suffers for lack of rain. In lessons on animals, again, the same process can l)e carried on to a great extent. The food of cats and horses can be deduced from their teeth ; the digestive organs of a hen from its want of teeth ; the teeth of a mouse from the fact that it can gnaw through boards ; the speed of a greyhound from the animal's broad chest and long sinewy limbs ; the aquatic habits of a duck from its webbed feet, and the short legs of a swallow from its long wings ; and no injustice would be done to a teacher if his skill and the educative value of his lessons were measured by his success in making children reason out conclu- sions from observed or stated facts. One sometimes hears a kind of counterfeit eliciting, wherein the questions are directed, not to making children think, but Counterfeit to making them give a certain word. An infant- eiiciting. school teacher points to a letter and asks what it is. There being no answer she proceeds, 'What makes honey?' The child replies, 'A bee.' 'Yes,' says the teacher, 'and this letter is B.' Another teacher shows some tallow and asks what it is. The children reply, ' Fat, lard, dripping.' Instead of making them smell it he says, ' What are candles made of? ' and thus gets the word desired without any exercise of the children's senses or intelligence. Emphasis 3 5 EMPHASIS The process of crystallization is full of suggestion to the teacher. A saturated solution of the substance to be crystal- Crystalliza- lizcd is made and allowed to evaporate ; threads are ''°"' suspended in it, and around them the crystals form. In every lesson there should be threads. In a lesson on Winds, for instance, unless the children can be made fully to realize the fact that heated air rises they will gain nothing. When the teacher has, by illustration, explanation, and recapitulation, made the fact clear in all its bearings, till it has become a part of the children's working knowledge, he can proceed to show the application of it in the production of wind. Then, what- ever may be forgotten, the leading principle will be remem- bered, and the children will be able to group the rest of the lesson around it. The principle will be the thread on which the information crystallizes. One often finds in the lessons of inexperienced teachers an entire absence of threads. The fundamental facts are not No emphasized, essentials and accidents are treated emphasis. ^-^^^ ^ith the result that children form no idea of the lesson as a whole, and perhaps remember an illustration but forget what principle it was intended to. make clearer. Where emphasis is not entirely absent one sometimes finds it in the wrong place. The most important parts of the lesson ■\yrong ^''6 allowed to take care of themselves, while great emphasis, gfress is laid on something incidental. In a lesson on Coins, for example, the teacher was silent on the necessity of alloying gold and silver, but he gave the exact proportions of the metals in each kind of coin, wrote the numbers on the board, and had them repeated till the figures were learned by heart. He thus caused a great deal of time to be snent ia 36 Longmans' Object Lessons labour which profited not, and the only comfort was that the children would soon forget what he had been at such pains to teach. SUMMARY A good blackboard summary of the lesson is a great aid to proper emphasis, because it calls attention to the leading, and Aid to orily to the leading facts, which are otherwise likely emphasis. ^^ ^g j^^j ^jgj^^ ^^ behind a mass of details. A goc5d summary is also a great aid to the memory, because it appeals to the eye as well as to the ear, and enables a clear and compre- hensive view of the whole lesson to be taken in at a glance. A summary What a •' summary (i) Should be methodically arranged and plainly should be. written. (2) Should be written little by little as the lesson proceeds, and not altogether at the end. (3) Should, if the children are young, contain no hard words. RECAPITULA TION A good summary is a valuable help to recapitulation, be- cause it shows the parts on which most stress ought to be placed. Children cannot take in much at once — There ^ must be how much they can take in depends on the nature revision. of the subject — but, whatever the subject may be, the teacher must, after proceeding a little way, pause to revise. Recapitulation (i) Should come immediately after the enunciation and explanation of fundamental principles, because it is useless to Recapitulation 37 go on building before ascertaining that the foundations have been well and truly laid. (2) Should come at every natural break in the lesson. (3) Should at the end of the lesson be twofold, first to deepen the impressions that have been made, and then (with- out the summary) to show whether the lesson has been eifec- tively learned. (4) Should be chiefly in the form of questions. To re-tell is almost useless, because the facts have lost the charm of novelty, and little mental effort is required merely to listen to them a second time. Part II FULL TEACHING NOTES OF COURSES OF LESSONS ON ELEMENTARY SCIENCE [If the following Lessons are given at the rate of one a week, and thoroughly reviewed from time to time, they will provide work for four or five years. Teachers and pupils should make large use of cyclope- dias and other sources of information. Hence the book offers a course of Elementary Science for lower grades, leading up to the specific study of Zoology, Physiology, Botany, Chemistry, Physics, and Geology, which is to be undertaken in the higher grades.] NOTES OF LESSONS FIRST YEAR A : Lessons on Common Properties SOLVENTS AND SOLUTIONS [Two lessons, the division being left to the discretion of the teacher.] Evaporation. — Pour a little water into a watch-glass or evaporating-dish, and place over a Bunsen burner or spirit- lamp. When vapour begins to rise ask, ' What is this ? ' Chil- dren will answer ' Steam,' and there is no need at present to bring in the terms vapour and evaporation. ' lVhat7^ias it before it was steam ? ' ' What changed it into steam ? ' Continue the evaporation till the water has entirely disappeared. Show the dry dish, and emphasize the fact that the heat has made the whole of the water pass away into steam. Solution. — Drop a lump of loaf sugar into a tumbler or test-tube containing clear water. Let the children watch the sugar dissolving. ' What has become of the sugar ? ' The children will answer that it is melted. Say that dissolved is the word commonly used. ' Where is the sugar ? ' 'How do you know that it is in the water ? ' Let the water be tasted. Explain that the sugar has been divided into very little pieces which are mixed with every part of the water. Recovery of solution. — 'How many things have I put into 41 42 Longmans' Object Lessons this glass?' 'How can I separate the sugar from the water V [Probably no answer.] 'If the water were driven away, what would be left in the glass ? ' 'How did we drive away the water just now V Evaporate some of the solution, and let the chil- dren see and taste the sugar recovered. [To save time, and to obtain good results, the water should be saturated with sugar, and only a httle of the solution evaporated.] A saturated solution. — Into a small glass containing cold water drop finely powdered nitre (saltpetre), a little at a time, and stir with a glass rod. Make the children observe that the nitre is dissolved. Continue to add nitre till it begins to fall to the bottom of the glass. Thence bring out the general fact that water will dissolve only a certain quantity of a thing. Hot water. — Pour some of the saturated solution into a beaker. Emphasize two facts: (i) That the water is cold; (2) That it will dissolve no more. Place the beaker above the burner or lamp. When the water is hot, add more nitre and stir. It is dissolved now. Thence bring out the general fact that hot water will often dissolve more of a thing than cold water. Soluble and insoluble substances. — Provide a number of substances, and let the children discover by experiment which are soluble and which are insoluble in water. Make two lists on the blackboard. The soluble substances should include alum, sugar, and copper sulphate, and the insoluble sealing- wax, camphor, indiarubber, and fat. Oil. — Half fill a test-tube with water. Pour some oil on the water. Shake, and show that the oil will not dissolve. To increase the difference in appearance between the two fluids, colour the water with red ink or an aniline dye. Alcohol. — Sealing-wax was just now shown to be insoluble ia water. The wax will dissolve in alcohol. So with camphor. A pretty appearance will be obtained if a little water is dropped into the solution of camphor.. Benzine. — Fat (which would not dissolve in water) will dis- solve in benzine. This is the reason why benzine is used to get grease spots off clothes. Illustrate with a greasy rag^ Crystals — Salt-Making. 43 Naphtha. — Indiarubber (which would not dissolve in water) dissolves in naphtha. That is the way in which it is dissolved for mackintoshes and other water-proof articles. ^Preparation for the next lesson. — In the saturated solution of copper sulphate (blue vitriol or bluestone) suspend in the presence of the class a small object (such as a stone), and say that you will let the solution stand till the next lesson. In the saturated solu- tions of alum, nitre, and sugar suspend pieces of string. Ask the children to do the same with a solution of alum, and to bring for the next lesson the strings with all that will be found cUnging to them.j FlC. 2. CRYSTALS. SALT-MAKING Fig. 3. — Crystal, of alum. Crystals. — Ask how many children made solutions of alum as requested at the end of the last lesson. Examine the strings, and say that the bright little things clinging to them are called crystals. Produce the solutions set aside from the last lesson, and let the children observe the crystals. 'In what things sold hy the grocer do we see crystj.ls ? ' [Sugar-candy, ' crystallized ' sugar, and salt.] Show each. Salt. — In some parts of the country men find on digging underground great rocks of salt. Show rock-salt. Also show some table-salt, and question out the differences between the two. Explain that the difference in colour is due to ' dirt ' mixed with the salt. ' IVho has seen a spring ? ' ' Where did the water come from ? ' ' Suppose the water had touched some rock-salt, what would it do to the salt? ' Illustrate by dissolving some rock-salt, and say that salt springs are found in some parts of the country. 44 Longman-i Object Lessons ' How did we get the sugar out of the water last lesson ? ' ' How can men get the salt out of the water from salt springs? ' Prepare a solution of salt. It need not be saturated. Evapo- rate by a gentle heat. If the solution is allowed to boil we shall have a shapeless mass instead of salt crystals. To get clean salt out of rock-salt men dissolve the rock-salt, and then let the water pass off in steam. [The other processes can at present be ignored.] SUSPENSION. POROSITY Solution and suspension. — Drop a little copper sulphate (blue vitriol or bluestone) into a beaker containing clear water. When it has dissolved ask, ' What has become of the bluestone ?' 'Can we see any of it ? ' ' IV/iy not?' ' How can we see that it is mixed with the water ? ' Drop a piece of chalk into another beaker containing clear water. Make the children see that it is not dissolved. Take out the piece of chalk and drop in some powdered chalk. Mix well. ' Where is the chalk now ?' 'Is it dissolved? ' Let the water stand, and make the children note that the chalk sinks to the bottom. Go through the same process with some other insoluble powder, as coal, charcoal, flour. ' What became of the copper sulphate ? ' ' What became ■ of the chalk ? ' Bring in the term suspended now. Pour the solution of copper sulphate into the beaker con- taining the chalk. ' How many things are there now mixed with this water ? ' ' The bluestone is ? ' ' And the chalk is ? ' Filtration. — 'How did we separate the salt from the water in our last lesson ? ' We will separate the chalk from the water in another way. Inside a funnel (of glass, if possible) place a piece of filter- paper. Blotting-paper will answer the purpose. Filtering- paper is sold ready cut in circles. If blotting-paper is used that must be cut into circles. Fold the paper to form a semi- Siispeitsion — Porosity 45 circle. Fold again to form a quadrant, then open out so as to form a conical cup by taking three thicknesses of the paper Fig. 4. on one side and one thickness on the other. Place in the funnel. [A little water may be necessary to make the paper stick to the glass.] Pour the mixture very gently to avoid breaking the paper. [It is a good plan to let the mixture run slowly down a glass rod, the end of which nearly touches the paper.] The chalk remains on the paper, while clear water runs through. Pores. — Ehcit that the water could not have run through if there had been , no holes in the paper. These holes are calXeApores, and the paper is said to be porous. Elicit also that the pores must be very small, or the grains of chalk would have passed through. Produce a number of porous substances, such as sponge, bread, a piece of cane cut diagonally, lumps of sugar and salt, charcoal, sandstone, brick, blotting-paper, &c. Let the chil- dren examine them, beginning with the substances that have the largest pores. Ask the children to separat" the substances that have pores from those that have none. 46 Longmans Object Lessons The sugar, salt, charcoal, sandstone, and brick will probably be placed in the second division. Show that these are porous also. Let the salt and the sugar stand in a saucer containing colored water. In a very short time they will be colored also. ' What has colored these ? ' ' Where did it come from ? ' 'Ifow did it pass through the salt and the sugar?' Treat charcoal in the same way. Show that the brick and the sandstone are porous by dropping water on them. Show that the blotting-paper is porous by making it absorb some ink. FILTERS The essential property of a filtering medium. ^Repeat the filtering-paper experiment of the previous lesson, and elicit why the water passed through the paper while the chalk remained behind. Take out the filtering-paper and put a piece of sponge (not too fine) in its place. The liquid passed through carrying the chalk with it. 'How did the chalk pass ? ' ' Why did it pass through the pores of the sponge and not through the pores of the paper?' Mix sawdust with water, and pour on the sponge- ' Why did not the sawdust pass through ? ' Emphasize the fact that if we want to filter we must use something which has very small pores. A flower-pot filter. — Make a rough filter by placing a sponge above the hole of a flower-pot, with alternate layers of powdered charcoal and sand above that. Show its action by passing water discolored with some powder (such as chalk, flour, or charcoal) through it. A table-filter. — A table-filter, being of glass, is excellent for the teacher's purpose. Show its action. 'Where is the dirt which was in the water at first?' Hence elicit that the char- coal (or other filtering medium) must be frequently cleaned. Use of filters. — Bring this out by a few questions. Recall the distinction between dissolved and suspended taught in a Sugar 47 previous lesson. Pass through filtering-paper water with pow- dered chalk suspended and copper sulphate dissolved in it. Emphasize the fact that the filter keeps back only the suspended impurity. Waterworks. — If there are any waterworks in the neighbor- hood of the school, the children will be 'interested to learn that the filtering-beds do not differ in principle from the flower-pot filter made in their presence. The water passes first through a layer of sand two feet deep, then through four layers of gravel each six inches deep, the gravel increasing in size downwards. [This is for purposes of aeration, of which nothing need be said now.] SUGAR [Before the lesson let a solution of sugar stand so that crystals may be formed.] Sugar-cane. — Sugar is made from the juice of the sugar-cane. The ' cane ' is a kind of tall, thick, strong grass, which grows in very hot countries. Show picture, or draw one on the black- board. The cane is full of pith inside. Illustrate pith by show- ing a fresh-cut piece of elder-wood. The pith is fiiU of sweet juice (like the pulp of an orange). Cutting. — When the canes are ripe they are cut down close to the ground, and taken to a mill. Crushing. — There they are passed between large iron rollers, to press the juice from them. Separation of the sugar from the molasses. — The juice is first filtered and then run into tanks. Lime is added to neu- tralize a shght sourness due to a process of fermentation. 'Have you ever noticed a sourness about old molasses ? ' Procure some and add some lime or soda. The juice is heated gradually, and a thick scum rises to the surface. Then the clear liquid below is drawn off and boiled down to the crystallizing point. It is then removed to coolers, and allowed to stand several days, until as much sugar as possible has deposited in crystals. 48 Longmans' Object Lessons The part of the juice which will not crystallize is called molasses. The molasses is either drained from the sugar, or removed by a centrifugal separator, which has very numerous uses, and might well be made tlie subject of considerable study. , Make a solution of sugar. 'How can we get rid of some of the water?' Illustrate. The clear juice is boiled in the same way till it becomes thick enough to form crystals on cooling. Show the sugar crystals prepared, and refer to the former les- sons on Solutions and Crystals. Molasses. — Add two tablespoonfuls of moldsses to a tumbler half-full of water, and crumble into it a small part of a yeast cake. Allow it to stand in a warm place for several days, or even weeks. Observe occasionally the alcoholic odor. Rum is made from molasses. Refining. — The sugar is then sent to a refinery in order to be made pure enough for use. ( 1 ) It is first dissolved in warm water, a little lime is added and the mixture is filtered through thick folds of cloth. Illus- trate. (Fig. 6.) (2) The syrup is now clear, but it is still discolored. To make it white it is iiltered through animal charcoal (that is, charcoal made by heating bones in closed iron vessels) . Illustrate the filtering. (3) The sugar, which will form crystals, must now be separated from the syrup, which will not. Remind children of the experiment in a previous lesson, when salt crystals were obtained from a solu- tion evaporated at a gentle heat. This is the way in which sugar crystals are obtained. Illustrate. (4) The sugar is poured into, moulds, formerly conical, now gen- erally cubical. Illustrate on black- board. The uncrystallized syrup is treacle. The moulds are Fig. 6. Plastic Substances 49 placed point down, and the last remains of the molasses (now treacle) settle at the bottom. The discolored point of the sugar- loaf is cut off. Ask about sugar-loaves seen in grocers' shops. PLASTIC SUBSTANCES Plaster of Paris. — Show dry plaster of Paris. Let the children handle it. Ask them to make it into a ball, flower- pot, tea-cup, &c. They cannot. Drop the powder into water, and knead the mixture into a paste. [Remember that plaster of Paris dries very quickly.] Let children again handle it, and again ask them to make the same things as before. Using a tea-cup, saucer, or small flower-pot as a mould, make a similar article. Turn it out or break the mould. Emphasize the fact that the plaster can be formed into almost any shape. The mouldings on the cornices and the ornaments on the ceilings of rooms are made out of plaster of Paris. Sand. — By way of contrast moisten coarse sand, and show that it cannot be moulded. Clay. — Before the lesson thoroughly 'dry and powder some clay, and go through the same processes with the powder as with the plaster of Paris. Among other things mould two small bricks, and announce that for the next lesson one of them will be left to dry, and the other will be dried and burnt. Ask the children to burn some clay and bring it with them for the next lesson also. Putty. — Similarly show that whiting, which is very fine chalk, cannot be moulded, but that mixed with linseed oil it forms putty, which can be moulded, and which becomes exceedingly hard when dry by reason of certain changes which the linseed oil passes through, which are too difficult for explanation here. [The litharge which is boiled with the linseed oil may be ignored.] Gutta-percha. — Show that it cannot be moulded when cold ; but that when plunged into boihng water it becomes soft, and 50 Longmans' Object Lessons can then be easily moulded. It is made into bags, bottles, shoe-soles, waterproof sheeting, &c. Plastic. — ' The plaster of Paris, clay, putty, and gutta-percha ■were all alike in one thing; what was that?' Things which can be moulded are said to be plastic. ' Name other plastic things' BRICKS Produce the two bricks made last lesson, one of which has been simply dried, and the other dried and burnt. ' Of what did we make these ? ' ' Which is the harder? ' ' Why ? ' Show a real brick. ' Of what is this made ? ' ' Why is it hard ? ' Brick-making. — (i) Illustrate mould by a pencil-box with- out lid or bottom. Mould on a drawing- or other board. Show that clay will stick to the wood. ' What does mother sprinkle on her kneading-board ? ' ' Why ? ' ' How shall we k^ep the clay from sticking to the board?' Sprinkle sand on the board. 'How shall we keep the clay from sticking to the mould? ' Children will probably suggest sprinkling sand. Show that the sand falls off, and thence elicit that the mould must be damped inside. Place mould on board, fill with clay, and smooth off superfluous clay with a ruler. Lift mould. (2) Show that the brick if not handled very carefully would lose its shape. Hence elicit that bricks after being moulded must be left to harden a little. (3) 'Who has seen a brick-yard?' ' Did you notice bricks drying? ' ' How were they placed? ' [In long, low walls with spaces between the bricks.] Get a child to place books similarly. 'Why are these spaces left?' 'With what was the top of the wall covered ? ' [Straw or boards.] ' Why ? ' If the children cannot suggest the reason, sprinkle a little water on the dried brick from last lesson and repeat question. (4) Burning is the next thing done. ' Where does mother bake her bread? ' [In an oven.] Bricks are sometimes baked in a kind of big oven called a kiln. More often they are piled Elasticity 5 " up loosely [' why ? '] , open places being left underneath the pile where fires may be built. [Illustrate again with books.J A fire is lit, and when the fuel is burnt out the bricks are hard. Differences between clay and bricks. — (i) Let children feel that clay is soft and plastic, while the brick is hard. (2) Pour water on both. It soaks into the brick, but not into the clay. (3) Hammer both. Clay is tough, and the brick brittle. Go through the same processes with some of the clay which the children themselves have burnt since the last lesson. ELASTICITY Elasticity by stretching. — Have a piece of what is famil- iarly known as ' elastic ' measured. Stretch it ; allow it to re- sume its original length, and have it measured again. ' What i^ this made of? ' [Indiarubber.] Emphasize the fact that the indiarubber gets back to its first size and shape. Elasticity by pressure. — Show a hollow indiarubber ball. Make children note the shape. Measure the circumference with a tape or piece of string. Squeeze the ball. Make the children see that the shape and size are altered. Allow the ball to resume its original size, and have it measured again. Emphasize as before. Treat a ball of wool and a piece of sponge similarly. By way of contrast show that a ball of putty or wet clay can be compressed, and will not resume its original shape. Make the hollow indiarubber ball rebound from the table. Ask the children to notice whether there is any change in the shape of the ball when it strikes the table. They will see that it is flattened. ' Make a solid indiarubber ball similarly rebound from the table, and a glass marble, a clay or stone marble, and an ivory 1 If the children are dull or backward, omit this paragraph. 52 Longmans' Object Lessons Fig. 7. ball rebound off the hearthstone, or (better still) off a slab of stone or marble placed on the table. The flattening in these cases will not be seen, but its effects can be made visible if a slab covered with some coloring matter be used. Show that when the ball is made only to touch it makes a small mark on the slab, but when made to rebound it makes a much larger mark, which is due to the flattening. By way of contrast show that a ball of lead, putty, or wet clay will not rebound. It is flattened, and will not resume its shape. Emphasize the fact that in the other cases the ball gets back to its first shape and size. Provide a bottle with a cork which will hardly go into the neck. Make the children see that the cork is too big. Then force it into the neck. Take it out, and make them see that it is again too big — it has gone back to its first size. Elasticity by bending. — Bend a piece of thin steel. Make children note that it goes back to its first shape. So with steel springs of various kinds. Elasticity by twisting. — Get a piece of small wire [prefer- ably of brass or steel] with a small weight at the end. Twist ; then hold by the free end, with the weight hanging down, and make the children see that the wire goes back to its first shape. The term. — Show 'elastic,' and ask what it is called. Any- tliing which goes back to its first shape and size after being stretched, squeezed, bent, or twisted, is said to be elastic. Degrees of elasticity. — We have seen that some things are very elastic and some are not elastic at all. Some things are a little elastic. Let the children divide the following articles into three classes, according to elasticity : — (iz) Stretching. — Indiarubber, cloth, leather, wire. Indiarubber 53 (J>) Pressure. — Hollow indiarubber ball, solid indiarubber ball, marbles, ivory ball, clay, putty, sponge, cork. (/) Bending. — Steel, tin, lead, a thin piece of wood, cane, whalebone, springs, a strip of glass, a lead pencil or penholder, a slate pencil. (a?) Twisting. — Wire, sliver of wood. INDIARUBBER What it is. — Indiarubber is got from the juice of some trees growing in the East Indies \^ India rubber'], Brazil, and other hot places. Holes are bored in the roots, trunks, and branches of these trees, and tubes or little gutters are put in. A milky juice runs out, and is caught in pots. Illustrate by sketch on the blackboard. When allowed to stand the milky juice separates into two parts — a thick, sticky part (which is the indiarubber), and a yellowish, watery part. Often this watery part is allowed to dry up, and the rest is passed through a machine full of spikes which tear it to pieces. It becomes hot and soft, so that it can be worked like dough and thoroughly washed. In some places when the juice has been got from the trees a lump of dry clay shaped like a pear is dipped into it and then held over a fire. ' What does the fire make the watery part do ?' A skin of indiarubber is left sticking to the clay. The dipping and drying are done over and over again till there is an inch or two of indiarubber sticking to the clay. Then the clay is broken out and the indiarubber is left. From its shape it is called bottle rubber. Show a piece. Some properties and uses. — ' We saw in the last lesson that indiarubber was ? ' [Elastic] ' Name things in which it is used because it is elastic' [Braces, garters, bandages, elastic stockings, &c.] If stretched and kept in cold water for some time it becomes inelastic. Show a piece that has been stretched and kept in cold water for some days. It will regain its elasticity when 54 Longmans' Olfject Lessons warmed. Before being woven into braces, &c., the indiarubber is made inelastic by cold.- Show that indiarubber is waterproof. Also that it is insoluble in water, but soluble in naphtha. Articles are made waterproof by having a solution of india- rubber spread over them. ' Name some things that are water- proof.^ Vulcanite. — Indiarubber is ' vulcanized ' by heating it with a small quantity of sulphur. Show vulcanized rubber. It is much more elastic than pure rubber, is not softened by hot water [hence made into hot-water bottles], and is not stiffened by cold. Ebonite. — Show a comb or other article made of ebonite. This is indiarubber greatly heated with a large quantity of sul- phur. ' Rubber.' — When we write with lead pencil we leave on the paper small grains of blacklead. When we rub these with indiarubber little pieces of the rubber are rolled off, and tlie little grains of blacklead stick to them. B : Lessons on Common Animals THE CAT [Illustrations : — A cat or kitten, and a saucer of milk.] Food. — Show cat. ' On what does this cat live?' 'If we did not gijie her aiiy food, on what would she live?' Emphasize the fact that cats catch their prey alive. Feet. — Make children count claws on fore feet [five], and on hind feet [four], and make them observe that the former are longer and sharper than the latter. Elicit reason. ' With which claws does the cat catch a mouse?' 'Which claws have most weight on them when a cat is climbing a tree?' Each claw has a sheath of thick, hard skin. Let children The Cat 55 see the sheath, and make the cat project and retract her claws. EUcit use. 'Why must the claws be sharps 'What would happen to them when the cat was walking if they had no sheath ? ' ' What would a mouse do if she heard the cat coming ? ' ' What makes the cat able to move without making a noise?'' Show pads under each toe and under the middle of each foot. Teeth. — Show. Then elicit that the teeth are formed for tearing, not for chewing. Tongue. — Let the cat lick a child's hand. To induce her to do so put a little milk on the hand. 'How does the tongue feel? ' Explain that the roughness is caused by little hooks fixed all over the tongue and pointing backwards. 'JIow does the cat get all the meat off a bone ? ' Let the cat lap some milk, and make the children observe the spoon-like action of the tongue. Eye. — Make the children observe that the pupil in a bright light is a narrow slit. ' What is the shape of the piipil at night? ' Compare admission of light through pupil to admission of light through window. 'Why do we pull down blinds when the sun is shining? ' ' Why does the cat's pupil become small in a bright light?' 'Why do we pull up blinds towards evening?' 'Why does the cat's pupil become large in a poor light ? ' Whiskers. — Make children touch the end. They will per- ceive that whiskers are stiff, and notice that the cat feels. 'Should we feel if the ends of our hair were touched? ' Elicit use of whiskers. ' Why does a blind man hold a stick before him ? ' ' Why do we hold our hands out wheii walking across a room in the dark?' 'When does the cat go about most?' Fur. — Make children feel that the fur is not oily. ,'Why does father oil his boots in rainy weather ? ' 'Does the cat dis- like wet?' 'Does the duck like wet?' 'Is its coat oily?' Habits. — Let the children say what they know about the habits of the cat. S6 Longmans Object Lessons THE DOG [Illustrate by a living dog.] Differences between cat and dog. — Cats see their prey, and catch it by creeping slily up to it. Dogs smell their prey, and catch it by running it down. Cats must therefore have good eyes and be able to move very softly, while dogs must have strong scent and be aisle to go fast and far. These differences will account for the differences in structure between cats and dogs. Feet. — ^Make children count the claws on fore feet [five] and on hind feet [four]. ' What is the difference between a dog's claws and a cat's?' [Dog's straighter and blunter.] ' Have you ever seen a dog chase a cat ? ' ' Where did the cat go to be out of the dog's reach ? ' [Tree.] ' Why did not the dog follow the cat ? ' ' Have you ever seen a cat catch a mouse or a bird? ' ' With what did she catch it? ' [Claws.] ' Have you ever seen a dog catch anything ? ' ' With what did he catch it? ' ' Why, then, does the cat need claws sharper and more curved than the do^s ? ' ' What covers the cat's claws ? ' ' See whether the dog's claws are covered.' ' Why does the cat's claw need a sheath while the dog's has none ? ' Make the children see that the dog cannot draw in his claws ; also that his feet are not so softly padded as the cat's. ' Why does the cat need to go more softly than the dog ? ' Teeth. — Show. ' What are these sharp teeth used for ? ' [Tearing.] ' Have you ever seen a dog eat a biscuit ? ' ' Could he tear a biscuit? ' Show action of the human jaw in grinding. Then show that the back teeth of the dog are capable of grind- ing. Make children see that the human jaw moves from side to side as well as up and down ; then tell them that the jaws of cats and dogs can move only up and down. Tongue. — ' How did the cat's tongue feel ? ' [Rough and The Dog 57 dry.J Make a dog lick a child's hand. 'How decs the dog's tongue feel? ' [Smooth and wet.] Eye. — ' fV/ien does a cat catch most mice 9 ' [At night.] Her eye must therefore be made to see in a bad light. ' JV/ien does a dog catch things?' [By day.] Question on the con- trast and the reason. Whiskers. — Recapitulate what was said about a cat's whiskers [P- SS]- Then elicit that as the dog is not a night animal, and does not have to pass through narrow holes, he does not want feelers. Then show dog's whiskers, and make the children observe that they are short and weak. Some dogs seem to have hardly any. Hair. — ' With what is the cat covered? ' [Fur.] ' And the dog?' [Hair.] Fur is the name given to the very fine, thick hair of certain animals. If a cat be examined carefully, ' over- hair ' will be seen growing through the fur. ' Who has seen a dog fond of the water ?' ' And a cat ? ' Habits. — Let the children say what they know of the habits of dogs generally. Blackboard summary. — Revise the lesson thoroughly, and place the heads of the comj^arison between cat and dog on the blackboard thus : — Cat Dog Prey . . Sees, creeps Smells, runs Feet . . . Claws sharp, curved Claws blunter, straighter Sheath No sheath Soft pads Harder pads Teeth . . Tearing i Tearing and grinding Tongue . Rough, dry Smooth, wet Eye . . . Changes shape of pupil; One shape of pupil ; for for dark light Whiskers . Long and strong Short and weak Covering . Fur Hair * The fact to be brought out is that cats are more purely flesh-eaters than dogs ; the fact that even cats have teeth which naturalists call molars may be ignored. 58 Longmans Object Lessons THE HORSE [Illustrate by means of a good picture. If the teacher had, or could borrow, a horse's skull it would be of great advantage.] Head. — Long ; rather broad at top ; hose narrow. Teeth. — 'What does a horse eat 9' 'What part of its food has a horse to cut?'' 'And what part to grind or crush?' ' What kinds of teeth must it therefore have ?' 'In what part of the mouth are the cutting teeth ? ' 'And the grinding teeth ? ' In front of each jaw the horse has six sharp, broad teeth for cutting. A little way from these there is on each side and in each jaw a long, sharp tooth called a tusk. 'How many of you have "played horse" ?' 'How many have had the bit in your mouths ? ' ' Could you close your mouths?' 'Why not?' Theace elicit that between the tusks and the grinding teeth there must in the mouth of the horse be a gap. This is called the ' bar,' and receives the bit. Beyond the ' bar ' come the grinding teeth. 'Does a horse eat flesh ? 'Are its teeth adapted to its man- ner of feeding ? ' Neck. — Long. A horse not fed by man would live on grass alone. 'How could it reach the grass if it had a short neck ? ' 'Why, then, is a long neck useful? ' Make children describe mane. Skin and hair. — Skin very thick ; made into leather for soles. Hair short and fine ; grows thicker in winter. ' Why is this fortunate ? ' Sometimes clipped. ' Why ? ' Elicit that if the horse be deprived by clipping of its natural covering an artificial covering should be provided. Tail. — 'Have you ever seen horses stung by insects ? ' 'If a fly settled on your hand, how zvould you frighten it away ? ' 'How does the horse, which has no hand, drive away insects ? ' 'Is it kind to crop a horse's tail ? ' Feet. — 'How many toes have you ? ' 'And a dog ? ' 'A cow ? ' 'A horse ? ' The Cow 59 ' With what is the horse's toe covered ? ' ' What is the use of the hoof? ' ' Why is it shod ? ' Elicit that the horse's hoof corresponds to our nails ; that therefore it has no feeling ; that the blacksmith pares the hoof and fits a hot shoe to it ; and that shoeing hurts a horse only when the nails are driven into the ' quick.' Kinds. — Dwell on the work and corresponding structure of a few typical kinds, as (i) The cart-horse, built for great strength, but not for swiftness. (2) The race-horse, built for great swiftness, but not for strength. (3) The hunter or carriage-horse ; intermediate. Habits. — Let children say what they know of habits. rJI£ COW [Illustrate by good picture, blackboard sketch, and, if possible, a cow's skull.] Where the cow lives. — ' Where does the cow mostly live ? ' [In fields. J ' On what does she mostly feed? ' Feet. — ' Will grass grow best in a dry field or a moist one ? ' 'If you tried to walk on stilts through a moist field, what would the stilts do ? ' [Sink in.] ' Would broad, soft shoes sink in ? ' Show picture of cow's foot ; ' cloven.' Describe. Illustrate action by separating first and second from third and fourth fingers. Teeth. — 'If you were in a field and wanted a handful of grass, how would you get it ? ' [Cut it.] 'And if you had nothing with which to cut it?' [Pluck it.] 'Could you by listening tell whether I was cutting or plucking grass ? ' 'How many children have been near a cow feeding in a field?' 'Did she cut or pluck the grass ? ' [Pluck it.] Describe teeth, and, if possible, show skull. Front of lower jaw six broad cutting teeth. Front of upper jaw no teeth. 6o Longmans\ Object Lessons but the gums form a kind of pad almost like indiarubber. No teeth like the horse's tusks. Twelve grinders in each jaw. With her long tongue the cow brings the grass between the front teeth and the 'pad ' ; then she gives a jerk and the grass is torn off. Chewing the cud. — 'Who has seen a cow biting her food ■when she was standing up and eating it?' 'Who has seen a cow chewing when she 7vas lying down and not eating?' She was then chewing the cud. Explain that lions, tigers, and other beasts of prey are very fond of cows. The grassy plains on which wild cows fed were exposed. It was therefore necessary that the feeding should be got over in a very short time. Cows therefore quickly swallowed all the food they wanted, and then retired to some safe place to digest it. ' What do we do to food in our mouths ? ' [Bite it. J 'And then?' [Swallow it.] 'Where does it go then?' [Into the stomach.] There it is changed into a liquid. ' Could we bring the food back from our stomachs into our mouths?' The cow can. She has four stomachs. She swallows the Fig. 8.— Stomach of cud-chewing animal [sheep]. «, oesophagus; h, paunch; c, honej-- comb; d, manyplies: e, true digestive stomach ; _/", first pan of intestine. food first ; then brings it back at her leisure, chews it, and swallows it again. The Ass 6i Neck.— Long. 'Why?' Horns. — Ask questions about means of defence of familiar animals. 'And of the cow ? ' Skin. — Thick and strong. 'Hence made into ? ' Hair. — Rather short. Can be pierced by insects. Cows much troubled by them in hot weather. Tail. — 'jffow does she get rid of them ? ' Tail long and tufted. Uses. — Question about uses of cow alive and dead. Blackboard summary. — Comparison between cow and horse : — Horse Cow Heaa . . No horns Horns Teeth . . Cutting teeth in both jaws Cutting teeth in lower jaw only Tusks No tusks Grinders Grinders Cud . . . Does not chew the cud Chews the cud Neck . . . Long Long Mane No mane Feet . . . One toe Two toes (cloven) Shod Not shod Tail. . . Long hair Tuft of hair THE ASS Comparison with the horse. — Show pictures of horse and ass, and ask in what way the two animals are alike, or nearly alike. (i) Shape of head. (2) Shape of legs. (3) Feet. The ass's hoof is longer and narrower than the horse's. Hence the ass is very sure-footed, and is used to carry persons up mountains. (4) The arrangement of the teeth is exactly the same in the two animals, though this cannot be seen from the picture. Question about the horse's teeth, and bring out the reason why 62 Longmans Object Lessons a horse can have a bit. 'Do asses have bits ? ' Are the ass's teeth like the horse's? Refer again to the two pictures, and ask in what way the horse and the ass are unhke. (i) Size. (2) Color. The horse may be black, gray, white, brown, or bay, or it may have large spots of any one of these colors, but it never has stripes. The ass has stripes and is generally brown, or of a brownish-gray ; a few are white, but black or bay asses are never seen. (3) Ears. (4) Tail. The horse's tail has long coarse straight hairs all over it ; the ass's tail has a tuft at the end. (5) Mane. The ass has very little. (6) Hair. The ass's coat is thick and warm, so that the animal does not need a stable. It can stand wet and cold which would be too much for a horse. (7) The ass is, for its size, stronger than a horse. Food. — The ass does not require such good food as the horse. It will find enough to live on at the roadside and on commons, and will eat thistles and other herbs that the horse will not touch. Habits. — The ass is generally considered stupid and obsti- nate, but naturally it is neither. Bring out by questions that both these qualities are increased by bad treatment, and show how asses should be treated. Then describe the qualities of asses in the East, where they are well treated. THE SHEEP Structure. — Show picture, and ask questions about the more obvious points in the structure of the animal, such as its size, the size and shape of the head, &c. Legs. — The legs are thin but strong. Sheep living in mead- ows have large, fat bodies, and cannot run very fast, but moun- tain sheep are swift. Feet.— Like a cow's, ' cloven.' The Pig 63 Teeth. — Also like a cow's. The sheep chews the cud. (Fig. 8.) Neck. — The cow's neck is long. 'Why?' 'What kind of neck has the sheep ? ' ' Why does the slieep not want a long neck ? ' Tail. — ' What kind of tail has the sheep ? ' The sheep's tail is not naturally so short as we generally see it, because lambs' tails are generally cropped. 'Of what use is the cow's tail to her ? ' ' Why cannot flies sting sheep ? ' ' Why do sheep not want long tails ? ' In one foreign country there is a sheep that has a long tail covered with fat, which people like very much, so a little two- wheeled cart is made for the tail to rest on. Wool. — The sheep lives out-of-doors all the year round. ' What kind of covering does it need ? ' ' What are our warmest clothes made of? ' ' When does the sheep need the warmest cov- ering?' In summer a wild sheep sheds its wool. Tame sheep would also shed theirs if it were not shorn off. Describe the washing and shearing. ' Who has ever felt the wool on a sheep's back ? ' ' What was it covered with ? ' [Oil] One would fancy that the sheep's wool would be soaked in the rain, but it is not. ' Why ? ' Horns. — Ask about the way in which various animals (e.g. the cow, horse, dog) defend themselves. 'How does the sheep defend itself? ' Most sheep have no means of defence, though some rams have horns. Elicit the gentle, harmless nature of the sheep. Habits. — Question, and where necessary tell, about the habits of the sheep, about shepherds, sheep dogs, &c. Uses. — Question, and where necessary tell, about the uses of the various parts of the sheep — flesh, tallow, wool, skin. The skin of lambs is made into gloves (called ' kid ') and into parch- ment. THE PIG Structure. — Show picture, and ask questions about the more obvious points in the structure of the animal, such as its size and shape. 64 Longmans Object Lessons Snout. — The nose is called a snout. It is long, pointed, and strong. Wild pigs live in forests and woods, and feed on acorns, beech nuts, and roots. The snout is used in digging these out of the ground when necessary. Pigs would spoil the farmer's fields by digging them up. To keep them from doing this he puts iron rings into their snouts. The rings hurt when the pigs dig, but not at other times. Pigs have a keen sense of smell, and are therefore used in France to find valuable roots called truffles. Teeth. — A pig has teeth for cutting, tearing, and grinding. It can therefore eat almost any kind of food. Boars, especially wild boars, have two large tusks. Food. — 'On what do pigs feed?'' Question out that pigs will eat many refuse substances, and that valuable flesh is there- fore obtained at a small cost. Skin. — The skin is very strong and thick. It is made into saddles and strong purses. Hair. — ' Who has seen a saddle ? ' ' Who has noticed little holes in it?' A bristle grew in each of these holes. Pigs have no hair, but all have bristles — some more, some less. These bristles are made into paint-brushes, and are used by shoemakers. 'How ? ' Tail. — The tail is very short and often curly. ' Of what use are the tails of cows and horses to them ?' 'Do pigs make the same use of their tails ? ' Feet. — The feet of the pig are cloven. ' Name other animals with cloven feet?' 'How many of these animals chew the cud? ' ' Does the pig chew the cud ? ' The Jews were allowed to eat the flesh of any animal that had cloven feet and chewed the cud. ' Were they allowed to eat pigs ? ' Flesh. — The flesh of the pig when fresh is called pork. When smoked or otherwise ' cured ' it is called bacon. The inside fat is called lard. Habits.— Question about the habits, and show that the pig is not naturally so dirty, greedy, and stupid as is often sup- posed. The Mouse 65 THE MOUSE [Illustrate by a dead mouse. A living one in a trap would also be useful.] Some habits. — Question on the habits of the mouse, and emphasize the following facts : — (i) It gnaws through boards. (2) Eats cheese, tallow, fat, &c., but nothing that needs tearing. (3) Passes through holes. (4) Is out by night. Teeth. — ' How would a carpenter make a square hole in a piece of wood? ' [With a chisel.] 'How does a mouse make a hole in wood ? ' [With its teeth. J Then the mouse must have teeth like chisels. ' And where must these teeth be ? ' Show the two chisel-like teeth in the front of each jaw. These grow as fast as they are worn out. They are hard in front and soft behind, and this keeps the edges chisel-like. ' With what do the cat and dog tear flesh ? ' [With their pointed teeth.] ' Where are these teeth ? ' Show that the mouse has no teeth for tearing. 'What kind of teeth are there at the back of the mouse's mouth V [Flat.] ' What are they for V [Grinding.] 'Name other animals with grinding teethe Mice, therefore, cut food with their front te'eth, and grind it with their back teeth. Claws. — Show claws. They are small and sharp, so that a mouse can cHmb anything rough. ' Who has seen a mouse climb ? ' Whiskers. — ' We had a lesson some time ago on an animal with whiskers. What animal was that ? '' [The cat] 'And what did we say those whiskers were for ? ' [To feel.] Show the mouse's whiskers. ' The mouse has to pass through ? ' [Holes.] ' Why does it want whiskers ? ' Ears.' — ' What animal is always trying to catch mice ? ' Hence elicit that the mouse must be very watchful and hear the slightest sound. Large ears. 66 Longmans^ Object Lessons Eyes. — Elicit similarly tliat the eyes must be large and bright, especially as the mouse goes about by night. Nose. — ' Has there ever been a mouse in your pantry ? ' 'What did it eat?' 'How did the mouse know that it was there V Hence elicit large pointed nose and keen sense of smell. Leg^s. — From the small holes through which mice pass elicit short legs. Fur. — A dull color, very silky. Habits. — Ask a few questions about these. THE HEN [Illustrate by good picture or by living bird. If the legs were lightly tied together the bird would be quite still. If nothing better can be procured the feet of a fowl would be useful.] Food. — Ask on what the hen feeds. Make clear that her food is either pecked up or scratched out of the ground. Thence elicit the kind of beak and claws she must have. Beak. — Show or draw picture. Compare with a duck's bill. Feet. — Three toes in front, a little joined. One small toe higher, behind. 'How do birds lay hold of branches ? ' 'Have you ever seen a hen on a branch ? ' Thence elicit that the hen has small grasping power in her claws. She can perch well because her body is well-balanced. 'How does she hold on to the perch while asleep ? ' Digestion. — ' What is the use of our teeth ? ' 'How many teeth has the hen ? ' [None.] Thence elicit that the food is swallowed whole. ' Where does it go first? ' [To the crop or craw.J Show in sketch, or let child feel in living bird. Food stays there for some time and gets slightly moistened. Food passes from the crop through the second .stomach (where it is still further moistened) to the gizzard. The sec- ond stomach, c, in the hen is so small that it escapes the notice The Hen 67 of most people who dress fowl. By passing the tube between the thumb and finger it will be detected as a somewhat thick- ened and hardened portion. The gizzard is a bag made of a \ Fig. 9. — A, gullet; B, crop; C, second stomach; D, gizzard. very strong kind of skin. Illustrate action with the palms of the hands. ' Who has seen a hen swallow stones ? ' These pass into the gizzard. ' 0/ luhat use are they there ? ' ' Why is gravel scattered for fowls ? ' Covering. — Warm. ' Why do we have guilts on our beds ? ' ' Of what are the warmest quilts made ? ' [Down — the softest feathers.] ' Who has seen a hen out in the rain ? ' 'And a duck ? ' ' Why did the duck look happy and the hen miserable ? ' [Water runs off the duck's feathers, but settles in the hen's.] Wings. — Of not much use for flying. ' Why ? ' 'Use ? ' Hatching. — ' What does the hen lay ? ' ' What sometimes comes out of the eggs ? ' ' What must the hen do to them first? ' Give details of hatching, and make the children say what they have noticed about a hen and chickens. 68 Longmans Object Lessons THE DUCK [This lesson would be best illustrated by a live duck, which can- not be difficult to procure. If a duck cannot be procured have a good picture, also a foot and bill, and for comparison the foot and beak of a hen.] A water bird. — ' Who has seen a duck ? ' ' Where did you see it ? ' ' Where do you most often see ducks ? ' The duck is made to live a great deal in the water. Food. — Slugs, worms, little creatures living in the water, and the soft stalks of plants. Feet. — Show feet of hen and duck. 'What is the differ- ence ? ' ' What is this skin called ?' 'So the foot is said to be ? ' [Webbed.] 'With what does the duck move itself in the water ? ' It pushes against the water with its webbed feet. 'How many of you can swim?' 'How do you hold your fingers when swimming ? ' [Close together.] Compare webbed foot to open hand with fingers close together, and an- other foot to hand with fingers spread. Legs. — Compare position of legs with those of hen or other non-aquatic bird. The duck's body is long and heavy. The position of the legs enables the bird to swim well. 'How does the duck walk?' [It waddles.J Ask a child to illustrate. ' Why does a duck waddle ? ' Feathers. — Show. Make the children see that the feathers are close, thick, and warm. Show down. 'What are the warmest quilts made of? ' [Eider down.] This is the down of the eider duck. ' Where does the duck live ? ' ' Why does it need a warm covering ? ' ' What does father do to his boots when he wants to keep out the wet?' [He covers them with oil] The feathers of the duck are covered with oil. ' Who has seen a duck and a hen in the rain ? ' ' Why did .the hen look miser- able and the duck happy ? ' ' Who has seen a duck pecking at its feathers ? ' It does this to break little bags which have oil in them. Bill. — Show beak of hen and bill of duck. The hen picks Wheat, Barley, and Oats 69 up grains from the ground. The duck sucks its food out of the mud, so it has a large spoon-like bill, with a sort of comb on each side through which the bird strains out the water and mud. Hatching. — Ducks are good sitters, but neglect the little ones as soon as they are out of the egg. Broods of ducks are therefore generally given to hens. C : Lessons on Plants WHEAT, BARLEY, AND OATS [( I ) In North America the word corn is applied specifically to maize (or Indian corn). In the British Isles the word is applied generally to the cereals most commonly grown — wheat, barley, and oats. (2) To children of seven or eight living in the rural districts this lesson will convey no information, and in their case a lesson on some other subject should be substituted. (3) The lesson should be illustrated by the ear, grain, and flour of wheat, barley, and oats.] Wheat. — The different kinds of wheat may be divided into two classes, autumn-sown and spring-sown. Elicit that as the autumn-sown must stand the cold of winter, it is the more hardy. " By a few years of successive growing,'' however, " spring wheat may be converted into the winter variety and vice versa.'' Both autumn-sown and spring-sown wheat may be either red or white, and each of these varieties may be either bald or bearded. Wheat grows to a greater height than barley or oats. The straw, when ripe, is yellow. The grain is short and rounded. Wheat is used for human food, being ground into flour which is made into bread, &c. Barley. — In an ear of wheat the grains are arranged round the stalk ; in an ear of barley they are arranged in either two 70 Longmans Object Lessons rows, one on each side of the stalk, or in another variety in four rows. Barley is always bearded. The straw is paler in colour than wheat, and not so tall. The grain is also paler and longer. Barley is chiefly used for making malt. Show malt, and explain what it is made into. Barley is also used as food for horses, cattle, and pigs, and in some country districts the very poor make bread of it. Oats. — If grown (as it often is) on a poor soil the straw of oats is short ; on a good soil it is as tall as that of barley or even of wheat. The ear is entirely different. It looks feathery, as each grain grows on a slender, drooping stalk. The grain is longer and thinner than either wheat or barley. It is either white or black. Oats are a most important food for horses, and oatmeal is quite extensively used as food among civilized men. Cultivation. — [Only the essential features need be described. The differences between the modes of cultivating the three grains may be ignored.] ( 1 ) Ploughing. — ' What is the first thing to be done if you want to grow anything in your garden ? ' 'And with what do you dig the ground ? ' 'If you had to dig many large fields, why would you not use a spade ? ' Show model or picture of a plough, and explain how the implement acts. (2) Harrowing. — 'With what do you break the lumps and smooth the ground when digging in the garden ? ' Elicit, as in the case of the plough, that a rake would not do for large fields. Then show model or picture of a harrow, and explain the action. (3) Rolling, if necessary, to break hard lumps. (4) Sowing. — Either broadcast with the hand [Illustrate], or in drills with a machine. Show picture and describe. (5) Weeding, if necessary. Why done. When. (6) Reaping. — Show models or pictures of scythe and cradle and various reaping machines. (7) Binding. — Explain and illustrate. On large farms the Rice 71 reaping and binding are now generally performed at one operation by a machine. (8) Carting. Threshing. — Explain what this is and how the process is performed. Illustrate the effect by rubbing an ear of corn. Call special attention to the mixture of grain and husks. Winnowing. — Ask how you could get rid of the chaff in your hand. Blow them away, and show that only the grains remain. On a large scale the blowing away of the husks is done by fans turning round in a winnowing machine. Grinding. — Briefly describe. RICE Where grown. — 'Who has seen it growing?' It grows in Japan, India, China, Egypt, the south of Europe, and the south of North America. Make the children realize that all these places are hot. Rice wants much water as well as heat ; hence it is grown in swampy places and where the fields can be flooded. Appearance. — Rice, when ripe, looks very much like barley. Cultivation. — The land is first covered with water till it is quite soft and muddy. The water is then drawn off, and the seed is sown broadcast or in drills. The land is again flooded till the seeds sprout. The flooding is renewed when the plants are about 3 inches high, and again when they are nearly ripe. Great care is taken to destroy weeds and hurtful insects. Harvesting. — When the grain is ripe the water is drawii off and harvesting begins. Labourers (who sink in the soft soil) cut down the crop with sickles. Paddy. — The grain is removed from the ears in various ways, which correspond to our threshing. Each grain is cov- ered with a brown husk. Cut grains of wheat, and show that they too are so covered. The removed husk is the bran. The husk-covered rice is called ' paddy.' The paddy is passed between mill-stones, which take away the husk without crush- ing the grain. 72 Longmans' Object Lessons Uses. — The children are faniihar with the use of rice as a food, but they probably do not know that a larger number of people live on it than on any other article of diet. The natives of India and China eat little else. At the same time, rice is not very nourishing, and the inhabitants of cold countries could scarcely live on it alone. Rice is also used for making starch. Place some ground rice in a muslin bag, and press between the fingers in a glass of water. The water becomes milky. Produce the same eifect with starch- in another glass of water. MAIZE OR INDIAN CORN Where grown. — Maize is also called 'Indian corn,' because it was the only grain grown by the Indians before America was discovered. It requires a climate ' with a summer four and a half to seven months long, without frost, the middle portion hot both day and night, sunny skies, sufficient rains to supply the demands of a rapidly growing and luxuriant crop, falling at such intervals as to best provide sufficient moisture without ever making the soil actually wet.' ' Show an ear of corn in order to let the children see what a productive crop it is. On this account the cultivation was introduced into those parts of the Old World where the climate is suitable, such as Portugal, North Italy, Roumania and the neighboring parts of Russia, and parts of Asia and Africa. Appearance. — Corn differs entirely in appearance from wheat, barley, and oats. The stalk is from 7 to lo feet high, strong, jointed and reedy, and covered with leaves. [Ears may be obtained from a grain dealer or from a seed store, and a few grains planted in a garden will produce stalk, leaves, ' tas- sel,' &c.] On the top of the stem grows a bunch of flowers called the 'tassel,' and lower down are one or more ears. 1 Tenth. Census of the United States : Statistics of Agriculture, Cereals, p. 92. Some Edible Roots 73 These are enclosed in a sheath of leaves, and consist of a stem called the ' cob,' with the grains arranged in rows as if closely stuck all round it. A long silky thread grows from each kernel and comes out at the top of the sheath. A fine powder, pro- duced by the tassels above, falls in great abundance during a portion of the season, and it is necessary that some of it should fall upon these silken threads if the kernels of corn are ever to be planted and grow. These silken threads become separated from the grains of corn when they are ripe. Cultivation. — Com is sown late in the spring so that there may be no fear of the young plants being injured by frost. Before being sown the seeds are soaked to soften the skin. Show seeds to let the children see how hard they are. They are then planted in groups about 3 feet apart. When they have sprung up they are, if necessary, thinned out. The ground is hoed to destroy weeds, and the soil is heaped up around the roots to give them more food. When the crop is ripe the stalks are cut down and the ears twisted off- Uses. — In the British Isles maize is not much used as food, except in the form of 'corn-flour,' but a good deal of ' Indian meal ' is given to cattle, pigs, and fowls. In the United States it is used in many ways. The green, unripe heads are a favour- ite vegetable, the grains being eaten with meat (like peas in England), and a preparation known as hominy (a kind of pud- ding made from coarsely ground corn meal) is also much liked. In Mexico maize is the principal food of the people. It is also much eaten in North Italy and in Rou mania. SOME EDIBLE ROOTS Carrot. — Show. Ask what part of the plant it is. Roots shaped like that are called /a/- Wf^/j. 'Why?' ' Name others.' [Turnip, parsnip, radish. J Cut the carrot across. Show that it consists of two parts : outer softer and sweeter than the inner and of a darker color. 74 Longmans' Object Lessons Let the children say what the color of each is. The inner part is 'woody.' From the top of it spring the leaves. Used as food for man, also. for horses and cattle. Sugar has been made from it. Parsnip. — Belongs to the same order as the carrot. Com- pare the two in shape, size, and structure. The parsnip is more hardy than the carrot, and may there- fore be left in the ground all through the winter. Turnip. — Two common forms are grown — the ' turnip ' and the ' ruta-baga.' Compare the two for shape. Either may have a variety of color. Grown in fields. Seed sown in drills. Thinned with a hoe. Used for flavoring soups, &c. Also eaten with meat, but chiefly cultivated as winter food for sheep and cattle. Radish. — Belongs to the same order as the turnip. There are a great number of varieties in cultivation. Show as many as possible. Compare taste i f a radish peeled with one un- peeled. Generally eaten raw in salads. [When the children see that the lesson is on roots used for food they will expect the potato to be included ; but though this is popu- larly known as a root, it is really the tuber growing on an under- ground stem. (See p. 221.)] SOME EDIBLE 'VEGETABLES' Potato. — Show. ' What part of the plant is it? ' Children will probably say it is a root. Explain what part of the plant it is. The buds which it gives off in the form of eyes [Show] prove that it is not a root. Planted in the spring. When the ground has been dug each potato is cut into pieces, each piece containing an ' eye.' Planted in rows. When the shoots are 3 or 4 inches high they are earthed up. The flower is white or purple. When the leaves begin to wither the tubers may be dug. The potato is a native of America. There is much un- Cocoa 75 certainty as to when it was introduced into Europe, but it is believed to have been grown first in Italy and then in Spain. [The statement that Sir Walter Raleigh brought it to Ireland in 1586 will not bear examination.] Pea. — The garden pea generally climbs on ' sticks ' placed for the purpose, and has flowers arranged two or three on a stalk. The garden pea is grown as food for man. Describe mode of cultivation. 'How do you spell the plural? ' Bean. — Compare with the pea as to size, shape, stalk, and flower. Beans are boiled and eaten by man. Onion. — Is the iuli of a plant. Show roots. Cut to show structure. It is very nourishing, but has a strong smell and pungent taste. COCOA Cocoa and cocoa-nut. — Cocoa and the cocoa-nut grow on two trees entirely different. The cocoa-nut is the fruit of a palm ;, the cocoa bean (of which cocoa and chocolate are made) is the seed contained in "the fruit of a tree something like a cherry tree. The proper name is cacao.' Where grown. — The cocoa tree grows best in countries which are very hot and moist — such as Ecuador, Trinidad, Venezuela (Caracas), and Northern Brazil. The tree. — The tree is from 15 feet to zo feet high-. Make concrete. Its trunk is straight and slender. The leaves are much like those of a cherry tree. The flower is of a reddish- yellow and without scent. The pod resembles a cucumber in shape and size, and, when unripe, in color also. When ripe it is red. It contains from thirty to a hundred seeds something like almonds. These are the cocoa beans. Cultivation. — The ground being thoroughly cleared of all weeds and stumps, the best and largest beans are thrown into water. Those that float are useless. Those that sink are kept in the water till they sprout. They are then planted in holes 1 The botanical name is iheobroma cacao. Theoiroma means ' food for tlie gods.' "j^ Longmans Object Lessons about 20 feet apart. As they grow they must be protected from the sun. The tree is at its best when about eight years old. Gathering. — The fruit is ripe when the beans rattle in the pod. It is gathered twice a year, the gathering being done by hand. Preparation.^ — After being taken out of the pods the beans are buried under a heap of green leaves. This soon becomes so hot that the hand cannot be held in it, and the beans fer- ment. The fermentation takes away a bitter taste from the beans and keeps them from growing musty. After being fer- mented the beans are roasted, and then bruised to loosen the skins. When these have been removed by fanning, we have the ' cocoa nibs ' sold in the shops. The beans are very oily, and when ground make a kind of paste. When this has first been allowed to harden and then been cut into thin slices it forms flaked cocoa. The oil is hard to digest, so it is removed when the best ' soluble ' cocoas are made. The oil is made into cocoa butter, which may be kept for any length of time without spoiling. Cocoa made into a paste, with sugar and some flavoring added, becomes chocolate. COFFEE [There ought to be no difficulty in procuring unroasted and roasted coffee 'beans' and ground coffee to illustrate this lesson. There may be some difficulty in getting a good picture of the tree.] What it is. — Coffee is a part of the berry or fruit of a tree. Where grown. — ^This tree grew first in Abyssinia. Then it was grown in Arabia and Persia, and now it is grown in most hot countries where the soil is suitable — such as Jamaica, Brazil, Ceylon, Java, Sumatra, &c. The tree. — The tree is an evergreen, with leaves much like those of the laurel. If allowed to grow it would be as big as Oranges and Lemons "JJ a large apple tree (about 20 feet high), but it is kept at a height of 6 or 8 feet. The flower is of a beautiful white, with a strong, sweet smell. The berry. — ^When the flowers fade the berries come in their place. Each berry, when ripe, is about the size and nearly the color of a cherry. After removing the fleshy outside we come to a kind of skin, inside which are two ' beans ' face to face. Show. The beans are on one side flat with a deep ridge, and on the other side curved. Gathering and preparation. — When ripe, the fruit is gath- ered, or shaken on cloths spread under the trees. The berries are passed between rollers which are close enough together to crush the fleshy part, but not close enough to crusli the beans. After being crushed the pulp is washed away, and the berries, still in their skin, are set to dry in the -sun. When dry they are passed between rollers which break the skin. The broken skin is blown away, and the beans are sorted and packed. Boasting. — Show unroasted beans and roasted. As for the difference in appearance, taste, and smell. The unroasted beans are greenish in color, and almost wanting in the peculiar taste and smell of coffee. They are roasted by being placed in an iron vessel which is turned round \_'JVAy?'~\ over a fire. The roasting should take place as short a time as possible before the coffee is wanted. Grinding. — ^This also appHes to the grinding. Describe the grinding. ORANGES AND LEMONS Orange. — Where gn/wn.—The orange is believed to be a native of China, but it is now grown in all parts of the world having a suitable climate. The United States grow a large number in Florida and CaUfornia, and also import many. Kinds. — Exhibit several varieties, including the blood orange. [' Why so called? '] The Seville orange has a bitter taste, and 78 Longmans Object Lessons is therefore not eaten like other oranges, but it is very useful. From its flowers we get orange-flower water and an oil employed in making eau de Cologne, while the rind is cut up for mar- malade. The tree. — The orange tree is small. It has dark-green leaves dotted over with little points filled with oil. Most of the children have seen the pretty white flower in the ' orange blossoms ' worn by brides. When ripe the oranges are gath- ered, wrapped in paper, and packed in boxes. Lemon. — Compare the orange and the lemon. They belong to the same family of plants. The lemon is a native of the north of India. Lemon juice is made into citric acid, which is much used in the preparation of effervescing beverages. The peel is used fresh in confectionery, &c., and candied it is used in puddings. Lime. — ^The lime belongs to the same family. It is grown for its juice. THE OAK [Provide a picture of the oak ; also specimens of the leaves, acorns, galls, and timber.] General appearance. — The oak is a tree with a thick trunk and large spreading branches. Roots. — Ehcit that if such a tree-were not held very firmly in the ground it would be blown down by storms, and that therefore it must have big, strong roots. When the tree is old some of these grow above ground. By referring to the way in. which the roots of a plant in a pot suck up moisture, elicit that the oak feeds (partly) by its roots, and that for this reason also they must be big. Timber. — The trunk grows outward, each year's growth making a ring round the older wood. Show the rings in a transverse section. The oak will live for hundreds of years. The timber is very hard. Hence it is used for making things which must be strong or stand wear. Name some things made The Oak 79 of oak. Formerly nearly all ships were made of it, both be- cause it is strong and will keep out water. Bark. — Show. When the trees are felled the bark is stripped off and sold to tanners. It contains something called tannin, which changes skins into leather. Acorns. — Show. They are the fruit of the oak, and if they are planted oaks will grow from them. Uncivihzed people often eat acorns, but as they have a bitter taste, civilized people, having other articles of food for themselves, leave the acorns to pigs, deer, squirrels, rats, mice, and birds. Oak apples or galls. — Show. There is an insect which pierces the leaf stem of the black oak and lays an egg there, together with a drop of poisonous fluid. The gall which forms is green at first, but brown when dry. It is frequently about an inch in diameter. SECOND YEAR A : Lessons on Common Properties HARD AND SOFT SUBSTANCES Soft and hard. — Provide as many substances of different degrees of hardness as may be readily procured, such as soap, putty, clay, brick, bone, ivory, slate, chalk, indiarubber, wood of various kinds, glass, emery-paper, lead, zinc, copper, tin, iron, steel (and other metals if possible) . Let the children try how many of these they can scratch with their finger-nails. Place these substances together as soft. The rest may be con- sidered hard. Comparative hardness. — By continued experiment make quite clear that the harder of two substances will scratch the other. Applying this test, arrange in order of hardness all the substances provided for illustration, and let the children note carefully the relative positions of the more important ones. Omitting the emery-paper, glass and steel will stand highest.' Diamond. — Let a child try to make a mark on the glass with the point of a steel knife. ' What does that show about the hardness of the glass ? ' Let a child scratch the glass with a piece of quartz. Ask what a glazier cuts glass with. 'What does that show about the hardness of the diamond ? ' Diamond is the hardest substance. It can be polished only by rubbing with diamond dust, and it has lately been used for boring very hard rocks. Emery. — Emery is a mineral.^ It is made into a very fine 1 Order of hardness of metals. — Steel, iron, silver, copper, platinum, gold, ' tin, bismuth, zinc, lead. 2 It gets its name from being found at Cape Emeri in the island of Naxos. 80 Fusion 8 1 powder and spread on glued paper. Elicit that as it is used to polish steel (which it does by rubbing off little bits) it must be harder than steel. Steel. — Steel is the hardest of metals. Get the children to name various tools made of steel, and to see that these would be useless unless very hard. But steel may be made harder or softer. Provide a piece of steel such as a big needle. Prove its hardness by showing that a file will not mark it. Heat it, and let it cool slowly, and with the file prove that it is now soft. Show that it will bend. Heat it again, and when it is red-hot cool it instantly by plunging it into cold water. Now prove that it is hard and brittle. Alloys. — ' What are our coins made of? ' ' IVhai would happen to thetn if they were soft?' Gold, silver, an;l copper are softer than iron. To keep them from wearing out quickly they are mixed with harder metals, gold and silver with copper, and copper with tin and zinc' Brass is a mixture of copper and zinc ; pewter of tin and lead ; type-metal (used also for shot and bullets) of lead and antimony. FUSION Solid and liquid. — See that the children can distinguish between solids and liquids, and ask about each of the sub- stances produced whether it is a solid or a liquid. Heat changes some solids into liquids. — Show a piece of ice or of butter. Warm it in an iron spoon, watch-glass, or evaporating-dish. 'What change has taken place in it?' ' What caused it to change from a solid into a liquid? ' Perform the same experiment with other substances, such as tallow, wax, lead (which should be melted in an iron spoon) . Emphasize the fact that each is at first a solid, and is changed by heat into a liquid. All solids do not melt with the same heat. — If a piece of 1 In the United States ' gold ' coins contain 9 parts gold, I copper and Silver. 'Silver' coins contain 92^ parts silver, 7 J copper. 82 Longmans Object Lessons ice has been provided, let a child hold it in his hand. The heat of the hand is enough to melt it. If no ice has been pro- vided, let a child melt a small piece of butter by holding it • between finger and thumb. Let the same child try to melt the lead in the same way. Hence elicit the fact that heat which would melt the ice (or butter) will not melt the lead. If there is a fire, put the poker or any other piece of iron in it. If there is no fire, hold a piece of iron wire in the flame of a spirit-lamp or Bunsen burner. The iron will not melt, but it becomes soft. By questioning about furnaces bring out the fact that at a very great heat iron will melt. Show some mercury. 'Is this a solid or a liquid? ' It is the metal that melts most easily. Only in a very, very great cold will it keep solid.-' The heat of fire will not melf platinum. Show. Hence vessels for melting gold and silver are made out of platinum. No one has yet succeeded in melting charcoal. Show. Some substances burn instead of melting. — Bring this out by trying to melt paper, wood, coal, &c. That fusion and not combustion would take place if oxygen were kept from these substances may be ignored at this stage. DUCTILITY, TENACITY, AND MALLEABILITY Ductility. — Hold a glass rod by the ends, and warm the middle in the flame of a spirit-lamp or Bunsen burner. (Fig. 35.) Show that when the glass has been softened it can be drawn out into a very thin ' wire.' Perform the same experiment with sealing-wax. Then show various metal wires and explain the method of making them. The metal is first made into rods about 1 inch thick by being drawn while red-hot between grooved rollers. 1 The melting-point is about — 38° F. The following are arranged in the order of the meliing-point : — Mercury, ice, butter, phosphorus, white wax, sul- phur, tin, lead, zinc, silver, gold, iron. Ductility, Tenacity, and Malleability 83 [There is no need to give the diameter of the rods, but show a piece of twine or a knitting-needle of the proper size.j The rods when cold are pulled through a draw-plate. The draw- plate is made of hard steel, and has a large number of holes growing gradually smaller and smaller. The rods are drawn through the largest hole first, then through the next, &c., till small enough. Fig. 10. — A Draw-plate (y) . Some metals cannot be made into very fine wire as they break when being pulled through the smaller holes of the draw-plate. Lead breaks most, and platinum least, easily. Platinum has been drawn so fine that over 33,000 pieces would lie side by side in an inch. Show an inch. Some of the finest wire in common use is the steel wire woven to form the gauze of safety lamps. Show wire gauze.^ Tenacity. — The best way to illustrate tenacity is to have thin wires of the same diameter but of different metals, and to suspend weights till the breaking-point is reached, making the children note the weight in each case. Where this cannot be done, let the same child break successive wires and note the comparative difficulty. Glass and sealing-wax will break very easily, lead less easily ; the hardest of all to break is steel, and the next hardest ordinary iron. Hence the cables of great ships and the ropes for suspension bridges are made of steel wire. Malleability. — Using a flat piece of iron as an anvil, show 1 The order of ductility (as given by Ganot) is platinum, silver, iron, copper, gold, zinc, tin, lead. 84 Longmans' Object Lessons that lead can be hammered out. Similarly hammer out a piece of copper wire. Then try to hammer out a piece of iron. Fig. By reference to a blacksmith elicit that iron can be easily ham- mered out when heated. Some metals can be beaten very thin when cold. Gold can be beaten thinnest of all metals. Question about gilding, and show gold-leaf. To make this the gold is first pressed in a rolling-mill. By rolling, the gold is made into plates so thin that twenty-five of them would make an inch — in other words, the plates are about as thick as two playing-cards. These are then beaten thinner with a hammer, cut, and beaten again and again. Show with the lead or copper that when thin metal is hammered it gets torn. To prevent this the gold is placed between sheets of goldbeaters' skin. Show. Thus beaten, the gold can be made so thin that 300,000 leaves would make only an inch. Show an inch, and show how many leaves of a paper book make an inch. Dutch metal, a kind of brass, can also be hammered out very thin. Show various metal foils and ask about their uses. The terms. — Anything which can be drawn out into wire is said to be ductile ; anything that is difficult to break is said to be tenacious ; and anything that can be hammered out is said to be malleable. Iron 85 In recapitulation produce wood, glass, sealing-wax, metals, &c., and ask to what degree they possess each of the properties dealt with in the lesson. IRON"^ Iron is hard and strong. — Get from the children and write on the blackboard the names of a few things made of iron, such as ships, bridges, pillars, engines, &c. ' Why would not lead do for these things ? ' Iron is used because it is hard and strong (or tenacious). Question briefly about the test of comparative hardness given in a former lesson, and apply it to show that iron is the hardest of the metals. Similarly review the lesson on Tenacity. Iron can be welded. — Heat two pieces of iron wire and weld them. Question about the work of a blacksmith. Iron is one of the very few metals which can be joined (or welded). Show how much less useful iron would be if it could not be welded. Iron can be hammered out. — Show piece of sheet iron, and get from the children names of things made out of it. Iron can be drawn out. — Briefly review lesson on Ductility. Show iron wire, and get names of things, great and small, made of it. Iron ore. — In many parts of the country large quantities of a kind of stone called iron ore are found. Show. This is generally a mixture of iron, clay, and lime. Furnace. — Show a picture of a furnace. By reference to the lesson on Fusion remind the class that at a very great heat iron will melt. 'Jf you want the fire at home to light up quickly what do you use ? ' ' What comes out of the bellows ? ' To get in the furnace the great heat needed to melt iron a blast of air is kept passing through. 1 This and the lessons immediately following it are intended partly to apply to special cases the preceding lessons on properties, and partly to give some information about the origin and preparation of the common metals. 86 Longmans Object Lessons Into the furnace a mixture of iron ore, limestone, and coke is tlirovvn. The lime, the coke, and the coal take away from the iron ore nearly everything ex- cept the iron. Into a tumbler of water drop a piece of wood and a piece of iron. ' Why does the iron sink while the wood floats ? ' ' JVhat will the iron in the furnace do when it is melted?' [Sink to the bot- tom.] 'Why?' A hole is then opened near the bottom of the fur- nace, and the iron runs out into grooves made in sand. Illustrate by a sketch on the blackboard. This iron is called cast iron. Show some cast iron. Ask the children to name things made of it. By exhibiting a broken piece, or by breaking, show that it is brittle. Wrought iron. — Cast iron is brittle because it contains a good deal of charcoal. Show. To get rid of the charcoal a draught of- very hot air is passed over the melted cast iron, which is also stirred or puddled. In this way the charcoal is burnt off and wrought iron is left. This is very tough, and can, when cold, be drawn into wire, and hammered into any shape when heated. Steel. — Steel contains less charcoal than cast iron and more than wrought iron. It can be made hard or soft by tempering. Repeat experiment from the lesson on Hard and Soft Sub- stances. Section of a Blast Furnace. LEAD Properties and uses. — Let the children compare the weight of lead with the weight of other substances. They will dis- cover that it is heavy. Lead 87 Let them scratch it with their nails. It is soft. It makes a mark — that is, it is so soft that little bits of it come off when rubbed — on paper. The ' blacklead ' of which pencils are made is not a kind of lead. Lead melts easily. Show this bj' melting some in an iron spoon. Because lead is heavy and melts easily it is used for shot. Show some. The melted lead is poured into a vessel with holes in the bottom [' Why ? '], and allowed to fall a great height [' Why ? '] into cold water. ' Why ; ' ' Who has seen u. shot- tower ? ' ' Why 7vould it not do to have soft shot ? ' Ham- mer shot and small pieces of lead to show comparative hard- ness. The shot is made hard by mixing a little arsenic with the lead. Show solder. Question about its use, and elicit that it must melt easily. Lead melts easily, but is too soft for solder, which is an alloy of lead and tin. Show the lead lining of tea-chests. The Chinese make this by pouring melted lead on one smooth flat stone and placing another upon it. Lead is malleable. Show this. Show a. piece of ' milled ' sheet lead. This could be made by hammering. It is made by being passed between rollers. Illustrate. Lead is flexible. Show that sheet lead and lead piping can be easily bent, and that they are not elastic. Bring out by questions that lead is adapted by its flexibility for use on roofs, as lining of cisterns, for gas and water pipes, &c. Pure lead is bright. Cut a piece, and contrast the color thus exposed with the dull gray surrounding it. This gray is a kind of rust, but as it does not dissolve in ordinary water there is little danger in using lead for the lining of cisterns. Lead ore. — The most common lead ore consists chiefly of a mixture of lead and sulphur. This is found in many parts of the country. Boasting. — The ore is first picked, broken, and washed to separate the earthy parts. The remainder is then roasted in a kind of long, low oven to burn away the sulphur. Smelting^. — The roasted ore is placed in a furnace and melted. 88 Longmans Object Lessons When melted, the lead sinks to the bottom [' Why ?''\, and the impurities rising to the top can be skimmed off. The lead is run into moulds, and is called /z^/ifa^. COPPER Properties and uses. — Produce some copper wire. Copper can be drawn out into finer wire than any ordinary metal, except gold, silver, and iron. Prove by experiment that copper wire is very tenacious (iron alone is more tenacious) and flexible. Hammer out a piece of copper wire to show that the sub- stance is malleable. When hammered or rolled out into sheets it is very elastic. Sheet copper is used for scuttles, kettles, &c. Also used to cover those parts of a ship under water, to pro- tect the wood from creatures living in the sea. Copper is a loud-sounding metal — hence used for gongs, bells, &c. Electric wires are generally made of copper. [The reason — viz. that copper is of all metals the best conductor of elec- tricity — need not be given at this stage.] Copper rust is green. Show. It is very poisonous. As sour fruit, vinegar, and other things cause copper to rust, the metal must not be made into any vessel used in cooking. Copper ore. — The most common ore of copper is a mixture of sulphur, copper, and iron. Ores of copper are found in the region of Lake Superior and many other parts of the United States, in England, Siberia, Brazil, Germany, &c. Show some copper ore. Roasting and smelting^. — The process of getting pure cop- per from the ore is too long and complicated to be described to young children. It consists of a series of roastings and smeltings. Alloys. — Brass [Show] is an alloy of about two parts of copper to one of zinc. The two metals are melted and mixed. Tin 89 and then cast into plates. Brass is malleable and ductile when cold. It melts more easily than copper, can be polished brightly, and does not rust quickly. Made into pins. Bronze. — Copper and tin. Very hard ; formerly used for weapons. Now used for statues and medals. Dutch metal. — Show. Eleven parts of copper and two of zinc. Almost as malleable and bright as gold. Used for 'gilding' cheap frames, &c. TIN Properties and uses. — Tin is of all common metals the easiest to melt. It will melt in the flame of a candle. [Melt some. If pure tin cannot be obtained, melt some tinfoil.] Tin, therefore, cannot be employed in any articles to be exposed to great heat. Tin is very malleable. Show tinfoil. A thousand sheets of the thinnest foil would be only an inch thick. Ask for the names of things packed in tinfoil. ' Why is the foil superior to paper?' [Not beingporous or absorbent it keeps out damp, and keeps in the aroma of the articles packed in it.] Tin does not rust easily. Show a piece of rusty iron. ' What caused it to rust? ' [The damp air.] Review that part of the lesson on Copper which dealt with copper rust. Cooking ves- sels made of iron or copper are therefore lined with tin. What is often familiarly called tin is really tinplate. This is tinned iron. Thin sheets of iron, first thoroughly cleaned, are dipped in melted tin. ' Why ? ' It would be useful to have frying-pans and gridirons tinned. ' Why are they not ? ' [The heat to which they are exposed would melt the tin.] Tin is soft. Show that it can be cut with a knife. It can be bent, but is inelastic. Show. It has little tenacity, therefore not used for wire. Alloys. — Pewter is an alloy of tin and lead. [The better kinds have antimony and copper instead of lead.] ' Uses and properties ? ' go Longmans' Object Lessons Britannia metal, a superior kind of pewter. ' Uses ? ' Bell-metal and bronze, chiefly copper with some tin. Solder, tin and lead. ' Uses and properties ? ' Manufacture. — ^Tin ore is found chiefly in Cornwall, Eng- land. [If possible show some.j It is first crushed and then washed. Much of the dirt passes away with the water. The ore is then roasted, like copper ore, to drive away any sulphur which there may be in it. Mixed with small coal and slaked lime, and strongly heated, it gets rid of most of the remaining impurities. It is then melted, and the impurities rise to the surface and are skimmed off. ZINC Properties and uses. — Show a piece that lias been exposed to the air for some time. It is dull. A little scratching will expose a bright surface. Only a very t'.iin coat of rust forms on it, and this is not poisonous. When cold, zinc is not malleable ; but when heated, it can be hammered or rolled out into sheets. These are flexible, and, as zinc is lighter than lead, it is used for roofs, gutters, pipes, &c. Zinc is hard. Show that of the common metals it comes next to iron and copper in hardness. For the properties named it is used to make vessels for holding water — baths, pans, cans, &c. The fact that its rust is not poisonous also leads to its use in cisterns, but it is said to give a taste to the water. Its hardness and indisposition to rust cause it to be made into saws for cutting blocks of salt. Elicit that iron saws would rust. Zinc and lead make a very ductile alloy. This wire is cheaper, softer, and more flexible than iron or copper wire. • Used by gardeners for tying trees and- shrubs and fastening labels. ' IV/iy ? ' ' Why would not twine do?'' ' Why would not iron wire do ? ' Pins 91 Just as iron for saucepans, &c., is coated with tin to prevent rust, iron for roofs, fences, and the walls of temporary build- ings is coated with zinc. The iron is dipped into melted zinc. The wrinkling (corrugating) gives strength. Refer to some place in the neighborhood where galvanized iron (as it is called) is in use. Preparation.— Zinc ore is found very extensively distributed over the world. The ore is first roasted to drive off the sulphur. It is then mixed with coal or charcoal and placed in large earthenware jars in a furnace. From each jar an iron tube passes into a vessel containing cold water. The zinc after melting passes through the tube as vapor, and is condensed in the water. PINS Properties. — Provide : — (i) A piece of thick wire. [Part of a knitting-needle will do.] (2) A crooked pin. (3) A pointless pin. [Cut the point off with a pair of scissors or a file.] (4) A headless pin. [Cut off head with scissors or a file. J (5) A piece of rough wire. Ask children to fasten pieces of stuff with these things, and thus elicit that a pin must be (i) Thin. (2) Straight. (3) Sharp. (4) Headed. (S) Smooth. Manufacture. eak if bent. — (i) Show that a needle is hard, and will Show that a pin is soft, and will not break if bent. ' What are needles made of? ' [Steel wire.] ' IVhat are pins made of?' [Brass wire.] Show. (2) Review what was said about wire-making in the lesson on Ductility, and add that brass wire of the proper thickness is supplied to the pin-maker. g2 Longmans Object Lessons (3) Cleaning. — Pour a few drops of sulphuric acid into a little water. Place a penny in the mixture, and then rub it. It will become as bright as when new. The brass wire is cleaned in much the same way. ' Why must it be cleaned? ' (4) Straightening. — '■Why must pins be straight?' The wire is straightened by being drawn between six or seven smooth iron pegs set upright in a table nearly in a line and some distance apart. The wire is made to pass on the left of one peg, the right of the next, &c. Illustrate by drawing a piece of wire between some nails fixed in a piece of wood. (5) Cutting and sharpening. — The wire is cut into lengths for six pins. Illustrate with a piece of brass wire. Both ends are sharpened by being ground first on a steel wheel cut like a file [Show a file, and how it acts], and then on a grindstone. Lengths for two pins are cut off, and the ends are again sharp- ened. Two more lengths are cut off, and when the remaining ends are sharpened the wire is cut in the middle. (6) Heading. — Smaller and softer wire is taken and wound spirally round a long piece of stiff wire of the same diameter as the pins. The coil is then cut up into bits containing two or three turns, each bit to form one head. Pins are then dipped into a heap of heads till each pin has taken up one. The pins are then placed point down in holes in a piece of steel, and the head is hanuuered on. (7) Tinning. — Refer to the tinning of iron for tinplate, and the zincking of iron for galvanized iron. Pins are tinned by being dipped into melted tin. ' Why are they tinned? ' (8) Drying and polishing. — The pins are dried and polished by being turned round in a barrel containing bran. (9) Papering. — Show a paper of pins, and explain the paper- ing. (10) Cost. — Calculate the cost of a pin from the price of a paper of pins. Pens 93 PENS [Specimens showing every stage in the process of pen-making may sometimes be obtained through the generosity of manufac- turers, and can always be bouglit from some of the school pub- lishers. These specimens form the best possible illustration of a lesson on Pens — indeed, they almost form a lesson in themselves.] Material. — Pens are made of ' ribbons ' of the best steel. Cleaning. — 'How was the brass wire used in making pins cleaned? ' The steel for pens is cleaned in the same way. Rolling. — The ribbons are passed between steel rollers till they are of the right thickness. Blanks. — By means of a punch pieces (called ' blanks ') are cut out. These are of the same shape as a pen would be if flattened out. Piercing.^ — Show the hole at the top of the slit. This is punched out, and the side slits, if any [Show pens with some], are cut at the same time. Softening. — The next processes are marking and ' dishing ' or curving ; but the steel is at this stage too hard for either, and it must therefore be softened. Refer to the lesson on Hard and Soft Substances, and ask how steel is softened. The ' blanks ' are placed in an iron box, heated, and allowed to cool slowly. Marking. — Show the maker's name and other marks. These are stamped on the soft steel. ' Dishing.' — The ' blanks ' are then curved by being pressed into grooves. Illustrate by pressing a piece of thick paper into a groove. Hardening. — The pens are then hardened. Again refer to lesson on Hard and Soft Substances. The pens are hardened by being heated and plunged into oil. Tempering. — Show that a pen is elastic, and that an inelastic pen would be useless. The desired elasticity is given by tem- pering. The steel is heated (but not made red-hot), and is allowed to cool. 94 Longmans' Object Lessons Grinding. — The pen is now properly pointed by grinding on a wheel made of emery powder and clay baked together; Refer to ' Emery ' in the lesson on Hard and Soft Substances. Slitting. — By means of a quill show that a pen which has no slit will not write. Each pen is laid on a chisel the edge of which reaches from the point to the hole. A similar chisel is forced down. The two meet, and the pen is sUt. Heating. — The pens are colored by heating. The shade of color depends on the amount of heat employed. B : Lessons on Animals THE LION AND THE TIGER Review rapidly lesson on the Cat. Treat the lion and the tiger as in structure and habits very like large cats. The lion. — Found in Asia and Africa. Size. — Show picture. The lion is about 4 feet in height at the shoulder. Show 4 feet. Color. — Tawny ; the same color as a mastiff. This is the color of the sandy deserts in which the lion lives. Elicit that the animal can therefore hardly be distinguished from sur- rounding objects by day, and not at all by night. Emphasize the fact that this enables the lion to capture his prey, and mention several other animals which have the same advantage. On the other hand mention several animals which are by similar means protected from the attacks of their enemies. Mane. — The lion when full grown has a thick, shaggy mane. The lioness has no mane. Tail. — The lion differs from the cat in having a tuft at the end of the tail. Climbing. — The lion also differs from the cat in being unable to climb. The Lion and the Tii;er 9S Teeth as in the cat. Draw teeth, and show that they are formed for tearing alone. Even the baclc teeth are unfit for Fig. 13. — Skull of Lion. grinding, and as the lion's jaws move only up and down, grind- ing would be impossible with any teeth. (Fig. 13.) Whisliers , feet (with pads), claws (with sheaths), and tongue as in the cat. Prey. — The lion, like the cat, does not chase its prey. It creeps silently up until about 20 feet off, and then springs. The tiger. — Found only in jungles in certain parts of Asia. Size. — Show pictures of lion and tiger, and ask children to compare the two animals. The lion is a little taller, but cer- tainly not stronger, fiercer, or more cunning. Color. — Bright gold with black stripes. Elicit, as in the case of the lion, that this makes the animal hard to distinguish, the yellow being of the same color as the tall grass amidst which the tiger lives, and the black stripes like the shadows. Structure. — There is no tuft to the tiger's tail. In other respects it resembles the lion. Hunting. — ^Tigers often lie in wait for men and kill many. They are therefore hunted more steadily than lions. Describe methods; (i) Traps; (2) By men on elephants. 96 Longmans^ Object Lessons THE WOLF AND THE JACKAL Review rapidly the lesson on the Dog, and dwell on the fact that in structure and habits the wolf and the jackal are really only fierce, wild dogs. The wolf. — Found in nearly every part of the world, hot or cold. Wolves were once common in the British Isles. Size. — Show picture. The wolf is about 2^ feet high at the shoulder, and about 3J feet long from the muzzle to the root ■ of the tail. Show these measurements, and compare the wolf in size to a St. Bernard or big Newfoundland dog. The tail, which is bushy, is about i^ foot long. Structure. — The muzzle slender. The ears are pointed and upright. The eyes are set slantingly. The teeth are like a dog's. The bite of the wolf differs from that of the cat tribe. The lion and the tiger seize their prey and then drag it to the ground. The wolf is not strong enough for this, so it gives a large number of sharp, quick, snapping bites, the teeth meeting each time in the flesh. In this way the animal attacked soon falls from loss of blood. Habits. — By reference to a fox-hunt elicit that dogs chase their prey in packs. Wolves do the same. Hardly any crea- ture is too large for them to attack. Going at a long, swinging gallop, they will follow for hours the creature they have chosen. When they overtake it they fall upon it from all sides, and soon bring it to the ground. They will devour even a horse in two or three minutes, and then they often fight among them- selves, eating up those of their number which are hurt or killed. Wolves are as cunning as foxes. Tell some story to illus- trate this. Wolves are very fierce and savage, but when caught very young they can be tamed, and they then become as friendly as dogs. When alone a wolf is cowardly, never, except when half mad with hunger, daring to attack a man. The Elephant 97 The jackal. — Where found. — The two most common kinds of jackals are found, one in India, and the other in South Africa. Structure. — The jackal differs from dogs and wolves in hav- ing a very long, pointed muzzle. It is also smaller than the wolf, being only about 18 inches high at the shoulder. Show this. Habits. — Jackals are rather cowardly. Like wolves, they hunt in packs, and united they can pull down a deer. They search for food at night, making a hideous yell. The jackal has been called the lion's provider, from the belief that it finds the prey which the lion kills. This is an error. Jackals often follow lions and tigers in the hope of securing what they fail to eat up. Like the wolf, the jackal if caught young can be tamed. THE ELEPHANT Where found. — Elephants live in the forests of Asia and Africa. Ask who has seen an elephant. 'Where did it come from ? ' The elephants seen in circuses are Asiatic ; the African is hunted for its ivory, not tamed. The African ele- phant generally has larger tusks, and always very much larger ears, than the Asiatic. Size.— The elephant is the largest land animal. It is gen- erally 8 or 9 feet high, but sometimes reaches 10 or 11 feet. Show these heights. Legs. — ' What kind of legs must the elephant have to hold up its great body ? ^ Show the thick, short, straight legs.' Compare with the legs of a race-horse in each respect. Feet. — The foot is very large. 'Why?' The hoof sur- rounds it, and is formed of a vast number of horny springs not unlike carriage springs. Elicit the effect of these, and tell that herds of elephants can pass through a forest almost without i A, child is said to have described an elephant as a square animal with a tail at each end and a leg at each corner. 98 Longmans Object Lessons Skin. — Elicit that as the elephant lives in very warm coun- tries it needs no fur and has little or no hair. Elicit also that as it passes through the forest, where it is liable to be scratched, it needs a thick, hard skin. Head. — Show that the head is large. Tusks. — From the upper jaw (in all African elephants, and in a considerable number of the males of Asiatic elephants) grow two very long teeth, called tusks, j^hese yield the best ivory, and are very heavy, weighing from 60 or 70 l6s-. to about 140 lbs. Trunk. — Contrast the neck and head of the giraffe with those of the elephant. Place a weight at the end of a stick, and let the children discover experimentally that the weight is easiest to lift when the stick is shortest. Thence show that the heavy head and tusks of the elephant need a short, stout neck. Elicit that with its short neck the tall elephant could not reach food from the ground. Hence the need for the trunk. The trunk is really a very long and strong nose with a finger at the end. It can seize anything and turn in any way. It carries food and water to the mouth. Without its trunk an elephant could not.live. Teeth and food. — The elephant has no tearing or cutting teeth. Its teeth are formed for grinding only, and it therefore lives on plants, leaves, fruits, and grains. Habits &c.-^— Give brief sketches of the hunting and taming of elephants. The school reading-books will probably furnish stories to illustrate the sagacity, strength, and other character- istics of the animal. THE CAMEL Kinds. — There are two kinds of camels, the Arabian, which is single humped, and the Bactrian, which is double humped. This lesson deals with the Arabian only.' 1 The dromedary is often spoken of as if it were a distinct species. It is only a ligbiter variety of tlie Arabian camel, used when great speed is required. The dromedary is related to the ordinary Arabian camel as the hunter is to the dray-horse. The Camel 99 Where found. — In Arabia and North Africa. Describe as vividly as possible the deserts over which the camel has to pass, with their loose sand often blown into blinding, suffocat- ing clouds, and with their absence of food and water. The remainder of the lesson will show how the camel is adapted by its structure for crossing such deserts. Size. — About 7 feet high — higher than a tall man. Covering. — Long hair, some coarse and some fine. The coarse hair is woven into cloth. ' Who wore a garment of camel's hair?' The fine hair is made into brushes for paint- ing. The color is an ashy brown. Teeth. — The camel chews the cud. Refer to the teeth of the cow. The teeth of the camel differ somewhat from those of the cow ; one great difference is that the camel has cutting teeth in the front of the upper jaw. Food. — Elicit from teeth that the food must be vegetable. It consists of grass, leaves of trees, dates, beans, grain, &c. Stomachs. — Refer to stomachs of the cow and the sheep. Elicit that the camel would perish with thirst if it could not go for a long time without water. It can do this by means of the cells in its second stomach. When the camel drinks it fills these c6lls and then closes them. When it becomes thirsty it opens them and allows a little water to escape. In this way the animal can go for about a week without drinking. Hump. — The hump is not a deformity, as the camel's ' back- bone ' or spine is as straight as a horse's. The hump is made up chiefly of fat, and seems intended to keep the camel alive when it can obtain no food. At the end of a long journey the hump is almost gone, and the camel is not allowed to travel again till the hump has grown to its old size. Legs and Feet. — Ask what would happen If a horse tried to walk over loose sand. Describe the large, broad ' shoes ' 'oy means of which men in cold countries walk over the snow. Show picture of the camel's foot, which consists of large elastic pads. These spread as the foot is placed on the ground. The camel has to kneel when being loaded. 'Why?' 'What would happen to the knees of a horse if it had to kneel often on loo Longmans Object Lessons the rough sand? ' The knees of the camel and the part of its chest which touches the ground are protected by hard leathery pads. Eyelids. — ' What happens to our eyes when the dust is Mow- ing ? ' ' What would happen to them if we were caught in a sandstorm ? ' The camel has shaggy, overhanging eyelids, which protect the eye from sand and from the bright sun. Nostrils. — Elicit that sand would suffocate if it got into the nostrils. The nostrils are long, and can be completely closed so that they look like a narrow slit. Temper. — It is a mistake to suppose that the camel is mild and gentle. It is sulky and bad tempered. Its legs often have to be tied/befc»e it will allowjtgelf to be loaded or even unloaded, and it ^^^^SM-UtaMature Study, Size &c. — Show pictures of various kinds of bears. Ask who has seen performing bears, and then question about size, shape, color, length of legs, &c. Teeth. — The teeth are formed both for tearing and for grind- ing, and bears, therefore, live on flesh and vegetables (roots, corn, fruits, &c.). Elicit that animals built like the bear could neither catch nor creep up to other animals. Feet. — Get from the children who have seen a performing bear that it stood easily on its hind legs. Sometimes a dog can be trained to stand with some difiSculty on its hind legs, but animals of the cat and the dog tribes usually cannot stand on their hind legs, because they walk on their toes. Bears can, because they walk on the sole of the foot (see Fig. 14). When fighting, bears stand on their hind legs and strike or hug with the front legs. Paws. — All the paws have strong, sharp claws ; no sheaths. By means of its claws the bear can climb and dig easily. ' Why should it want to climb ? ' 'And to dig ? ' The Bear lOI Hibernation. — Bears generally sleep through the winter. Elicit that fruits are plentiful in autumn, and not to be found in winter. Bears, therefore, get very fat in the autumn. About October they dig themselves dens under rocks or beneath the roots of trees, and there they pass the cold months without eating and seemingly half dead. Speak of the thick, warm fur of the bear. Kinds. — ^The bear generally seen in England is the Brown Bear, which is found in the woods and forests of several parts Fig. 14. — Skeleton of Bear. of Europe and Asia. This bear is fond of ants and their eggs, and of honey. The Black Bear is found in many parts of North America, but as it is much prized for its fine fur it is not so common nov/ as formerly. Lives chiefly on vegetable food. The Grizzly Bear is also found in North America. It is very fierce and strong, and will readily attack man. The color varies greatly, but there is always a tendency to whiteness in ■ the surface of the fur : hence the name grizzly. This bear lives upon animals of all kinds as well as upon vegetables. I02 Longmans Object Lessons The White Bear is found in the Polar regions. The feet are very long. Elicit that they are good for swimming. The soles covered with a very thick coating of warm fur. EHcit Fig. 15. that this will keep the feet warm And prevent their slipping on the ice. Lives chiefly on fish. 'Are there any fruits in the cold North ? ' Also fond of seals. The female sleeps through the winter, but the male aoes not. The Hare 103 THE HARE [For illustration, have a living hare, or a picture of one. For the teeth, have a skull. The animal so often called rabbit in our country is not a true rabbit, but a hare. The differences between the two are rather insignificant, however. True rabbits, although not found wild in the United States, are very abundant in the Old World.] Home. — Hares live in nests upon the surface of the ground. Rabbits live in burrows. Teeth, — Review what was said about the teeth of a mouse. The hare is, like the mouse, a gnawing animal. Show the two long teeth with chisel edges in front of each jaw. At the back of each jaw are grinding teeth. To show the action of the teeth and jaws try to get the living hare to eat some green stuff. Food. — Elicit that as the hare has no tearing teeth it cannot live on flesh ; but that as it has grinding teeth it lives on vege- table food. Hares, where they are abundant, do great damage to the farmers' fields. As they have a large number of young ones every year, they would destroy everything around them if many were not killed. Ears. — Elicit that as the hare has so many enemies it must be very watchful, and requires good ears and eyes. The ears are long and movable. 'Advantage of this ? ' Eyes. — Large and bright, placed one on each side of the head. Elicit the advantage of this. We can see only what is in front of us ; the hare can see nearly all round. Leg^s. — Long and thick, showing that the hare can run very fast. 'Why does it need to?' Hind legs longer than front, enabling it to jump well. 'Other animals with hind legs longer than front?' [The kangaroo is a notable example.] The hare can sit up on its hind legs. Feet. — 'How many toes on front feet ?' 'Hind feet?'' 'Are the daws like those of dog or cat ? ' 'Are there sheaths for the claws ? ' Whiskers. — 'Other animals with whiskers?' 'Use of the whiskers ? ' 104 Longmans Object Lessons Covering. — Soft, warm fur — so soft and warm that the skins are used to make muffs, caps, &c., and to line cloaks. Very young rabbits have no covering, but hares have coats of fur when they are born. Elicit that its gray fur keeps its enemies from seeing it easily, and that, as it has no burrows and cannot climb a tree, its only means of escape are its legs and its cunning, both of which serve it well. THE BEAVER Found. — Some beavers are found in the northern parts of Europe and Asia, but their great home is now the northern part of North America. Impress upon the children that the climate of those parts is very cold, and elicit that as the beaver spends most of its time in the water it needs a specially warm covering. Fur. — The beaver has two coats of fur — an under layer of short soft gray hair lying close to the body, and an upper layer of thicker and longer chestnut hair forming a kind of thatch. Because of its warmth beaver skin is much valued for muffs, jackets, cloaks, &c. Feet. — ' What sort of feet has the duck ? ' ' Why are they •webbed V The hind feet of the beaver are webbed for the same reason. Tail. — Compare the tail to the rudder of a boat and to the screw of a steamship. It is covered not with fur but with scales. 'Like ? ' Teeth. — The beaver is a gnawing animal. 'Like ? ' Food. — It lives on the bark of trees. Size. — The beaver is the largest of the gnawing animals. It is over 2 feet long from the nose to the root of the tail, and the tail is over a foot long. Dams. — In very cold countries the streams are often frozen down to the ground, and in the short, hot summer they are sometimes dried up. To keep both these things from happen- The Beaver 105 Fig. 16. io6 Longmans' Object Lessons Fig. 17. ing in the streams where they live, beavers make the water much deeper by building great dams right across them. Illus- trate by a good blackboard sketch, or by having a box or httle trough for the bed of the stream, and compare to a mill dam, or to the big pool the children themselves may have made by damming back the water in the gutter on a rainy day. Having chosen a suitable spot where there is a tree growing on the bank, the beavers gnaw at it till it falls across the stream. Should one tree not be long enough, they similarly gnaw another on the opposite bank. These trees form the foundation of the dam. A large number of logs and sticks are then gnawed, floated down the stream, pressed among the branches, and secured with mud and stones. Layer upon layer is formed in this way till the dam is high enough. An opening is left at the top. ' Why ? ' The labor spent in building dams must be very, very great, as they are 1 2 feet thick at the bottom, and sometimes 300 yards long. 'How many times as long as the school-yard ? ' [It is a popular error to suppose that beavers use their tails as trowels.] Lodges. — Near the dam the beavers build their 'lodges.' These are huts formed of branches, moss, and mud, in which several beavers live together. The walls are very thick, and, as the winter's cold freezes the mud, they defend the beavers against their enemies. Around the 'lodges' deep ditches are dug, and as each ' lodge ' opens into a ditch the animals can pass into the stream without going over land. Winter food. — Beavers strip the bark from the logs used in building their dams and store it for food in the winter. They also cut a vast number of small logs and fasten them under Tlie Swallow 107 water near their ' lodges.' When they feel hungry they dive for one of these logs, peel off the bark, and eat it, leaving the log to float down. THE SWALLOW [Except in towns that the swallow does not visit, this lesson should be given during the summer. If a bird cannot be procured, illustrate by means of a good picture.] The swallow is a 'bird of passage.' — By means of questions bring out clearly (i) That the swallow is oftenest seen flying about swiftly, not in a straight line, but in all directions. (2) That while flying it feeds on insects. (3) That insects abound in warm weather. (4) That the swallow is in this country only during the warmest half of the year. Birds which, like the swallow, spend only a part of the year in a country, are called birds of passage. Shape. — Draw oudines of two boats, one narrow with sharp bow, the other broad with flat bow. Ask which boat would io8 Longmans' Object Lessons pass most quickly through the water. ' Why. ? ' Then make children see that the swallow's body is shaped like the first boat. Contrast with the body of a hen. Wings. — Very long, narrow, and pointed. ' IV/iy does the swallow fly about so much ? ' ' What sort of wings must if have to enable it to fly about so much ? ' Compare wings with a hen's. Also with an eagle's or owl's. 'And to carry it to far coun- tries ? ' The swallow is believed to fly from Great Britain to the north of Africa in three days. The eagle and owl do not want to fly fast or far, but to keep up a long time and to carry their heavy prey. Their wings, therefore, are strong, but broad, not long. ' JVhy broad ? ' As the swallow has to catch insects as they fly, it must be able to dart through the air, and it has no weight to carry ; hence shape of wings. Legs, — Short and weak. Feet with four sharp claws, three pointing forward (four in the swift). 'What birds have you seen hopping about?' 'Have you ever seen a swallow hopping about?' 'Why cannot a swallow hop?' 'Why does it not need long or strong legs ? ' 'Have you ever seen a swallow hanging by a wall? ' 'How did it hang ? ' Beak. — 'The beak is short and so weak as to be almost soft, but of vast width proportioned to the size of the body. 'I'his may be easily seen in the common house-swallow, but more particularly in the swift or large black swallow and goat- sucker, whose heads may be almost said to be all composed of mouth, so wide and gaping are their large, short beaks. Consequently, when the supply of food is abundant they have little more to do than fly with op^ mouth and close their beaks upon the objects which cross their flight. This the swallow does with a sharp clicking jerk, which may be heard by an attentive listener on a calm day at a considerable dis- tance.' — Stanley's 'Birds.' Kinds (with nests). — (i) The swallow (proper). — Can be distinguished from the swift or martins by its steel-blue upper plumage and the two very long feathers that edge its forked tail. ' The swallow has perhaps never been known to build a nest in the open air. In barns and outhouses, upon the beams of The Ostrich 109 wood which support the roof, or on some stone jutting out of the wall or chimney ... we find its nest.' — Dixon's 'Rural Bird Life.' Question about building of nest. (2) The house-martin. — Resembles the common swallow in habits and appearance. Can be distinguished from it by the large white patch on its back and the absence of the acutely forked tail. ' Unlike . . . the swallow and sand-martin, the house-martin builds its nest in the open air,' ... on the rocks, under the eaves of buildings, or on the sides of windows or chimneys.' — Dixon. (3) The sand-martin. — Smallest of swallows. Back and headsoft brown ; quill feathers of wings and tail black; breast white, with a band of brown across the upper part. Builds its nest in sandy cliffs, banks of rivers, &c. Makes a narrow tunnel from 18 inches to 4 feet long, and at the end builds a nest of grass and feathers. (4) Swift. — Is unlike the true swallows in several respects — one already mentioned (all four toes pointing forwards). Swiftest; cuts through the air as though shot from a bow. Nest made of feathers and grass placed in a hole in a wall or rock or in an unused chimney ; hence called ' chimney swallows.' THE OSTRICH Where found. — The ostrich lives in South Africa. Describe the kind of country. As it is sandy the bird's long legs are useful [' Why V\; as there are no trees the bird does not want grasping claws or wings. A running^ bird. — Legs very long and very strong. Can break a man's leg with a kick. Two toes, the outer about half as long as the inner, which has a claw. Food. — In a wild state the bird lives chiefly on melons, which grow plentifully on the ground. Ifeck. — Elicit that as the legs of the ostrich are very long KIO Longmans' Object Lessons Fig. 19. The Herring in and its food is found on the ground, it must have a very long neck. Bill. — Draw on the blackboard a hawk's beak, formed for seizing prey, and a hen's, formed to pick up grain. Elicit that neither of these wou]d do for the ostrich, which has a bill something like a duck's. Size. — From the long neck and long legs children will gather that the ostrich is a large bird. Tell them it is the largest — from 6 to 8 feet high. Wings. — As the bird has long legs and can go faster than a horse it does not need to fly. Wings, therefore, very small in proportion. Like a hen's, they help the bird to run. Feathers. — Show. Though the wings are comparatively small, the feathers in them and in the tail are really large and beautiful. They are black, gray, and white, and worth a good deal of money. Eggs. — Very large ; contain as much as twenty-four eggs of hen. Hatching. — The eggs are laid in the sand and hatched by the sun, except in the parts furthest from the equator, where the sun's heat is not enough and the birds sit on the eggs. Hunting. — Hunted. 'JVAy?' Chased by men on horses. The birds run in a zigzag hne, but the horses keep straight on. Illustrate on blackboard. Ostrich farms. — In South Africa, and in California, ostriches are now reared on farms. ' IV/iy ? ' The eggs are hatched in incubators. TJI£: HERRING [Illustrate the action of the gills, fins, and tail by having a gold- fish or other living fish. For the special structure have a dead herring.] Some peculiarities of a fish. — Gills. — 'What do we breathe with ? ' ' What passes into our luti^s ? ' ' IVhaf does the air do in the lungs ? ' There is always a little air in the water. Show 112 Longmans' Object Lessons the bubbles in water which has been standing. Also boil a little water in a test-tube, and make the children observe the many bubbles of air which will rise to the surface. Fish breathe this air; but they have no lungs. They breathe by means of their gills. Show the folds in the herring's gill, and show the action of the gills in the living fish. The blood passes through the gills. 'What color are they?' 'Why?' When a fish breathes it takes water through its mouth and makes it pass over the gills, and the air in the water purifies the blood. Eggs. — Show a ' hard roe.' This is made up of the herring's eggs. ' What is the difference between the eggs of a bird and those of a fish ? ' [The shell.] 'How many of you have seen the " spawn " of frogs in pools and ditches in spring ? ' This is made up of the eggs of frogs. The eggs of some fish look like that. ' What causes a hen's eggs to hatch ? ' The eggs of fish are also hatched by heat, but it is the heat of the sun. By refer- ence to the times which it would take a large kettle and a small one to boil, elicit that shallow water gets warm sooner than deep. Fish that live in the depths of the ocean lay their eggs near the shore. Shoals. — Millions of herrings in shoals come from the deep sea to shallow water in their spawning season. ' Why ? ' They are then caught in seines and sweep nets. Description. — Using the herring provided get the children to describe it — length, shape [Compare to racing-boat or swift ship], eyes, no lids iJWhy?'^, scales [Note how they are sil- vered], fins, and tail [Show use by Hving fish]. Fishery. — Describe the fishing as graphically as possible. Curing'. — White herrings are simply gutted and salted. Other herrings are gutted, strung on sticks, and hung in a room which has fires (generally of oak) lit on the floor. If removed after twelve or fourteen hours' smoking they are called bloaters ; if allowed to remain about twelve days they become red herrings. Cotton 113 C : Lessons on Plants COTTON What it is. — Refer to thistledown, and to the seed in the middle of each little ball. Cotton is the soft white down covering the seeds of a plant. Where grown. — Cotton takes about seven months to grow, and, as the least frost injures it very much, it can be grown only in those parts of the world where for more than half the year there is no frost whatever. It also requires a fair amount of moisture, but too much rain is not good for it. It is there- fore grown largely in the south-east of the United States, in India, in Egypt, and in Brazil. The plant. — The plant is from 2 to 4 feet high (about the height of a gooseberry bush) . It has dark-green leaves, shaped somewhat like the leaves of the sycamore. The flower is in form very much like the single hollyhock, but is yellow in color with a purple centre. When the flowers go off, pods appear, about the size of an apple. These partly open, show- ing the cotton and the seeds. Show. The seeds are about as big as a pea slightly flattened. Cultivation. — In the United States cotton is generally planted in rows, pretty wide apart, to allow of hoeing and weeding. Where the climate is at all moist the earth is ridged up about the roots, so that when there is too much water it may drain off. Gathering. — When ripe; the cotton is gathered by hand, and placed in baskets carried by the picker. It is then dried in the sun. Ginning. — Before it leaves the plantation the seeds are removed by means of a gin. In India the gin consists of two rollers placed close together. The cotton is made to pass between them, and the seeds are left behind. In America a saw gin is used. This consists of a box, one side of which is made of strong straight wires so close together that the seeds 114 Longmans Object Lessens cannot pass between them. Small round saws work between the wires, dragging the cotton through and leaving the seeds behind. Bales. — The cotton is then pressed together very hard and packed in bales, which are sent to Lancashire and other places where the manufacture of cotton goods is carried on. Manufacture. — -As in the case of flax, the processes need be no more than indicated. CORK Bark. — Show pieces of the branches or twigs of several dif- ferent trees. Strip the bark off each ; show it, and get or give the name. Cork is the rough outer bark of a kind of oak which grows chiefly in Spain. The tree is much smaller than the English oak, being only about 30 feet high. Make the height concrete. The tree also differs from the English oak in being evergreen. Ask what that means. Stripping. — The trees shed their outer bark sometimes, but generally it is stripped off. One cut is made round the trunk near the ground, and another just below the branches. Then several cuts are made downwards from one ring to the other. The end of a kind of bar is placed in the cut, and the cork forced off the trunk. Illustrate with a pointer or poker. Care is taken not to injure the inner bark. If that were destroyed the tree would die. The tree is first stripped when it is about twenty years old, and it is stripped again every eight or ten years. Preparation. — ' What is the shape of each piece of cork when stripped off? ' In order to flatten it, it is placed in pits with heavy weights on the top. Illustrate. Water is then let into the pits, and the cork is left to soak for a time. It is then dried before a fire and slightly charred. This closes the pores \_'lVhy must the pores be closed ?'\ and makes the cork keep its flatness. Leaves 1 1 S Qualities and uses. — Show that it is elastic, and that water will not pass through it. Hence it is used for corks and bungs. It is very light. Show that it floats easily, and will bear a considerable weight without sinking. Hence it is used for ' life-preservers ' ; also for ' floats ' of fishing-nets. Being light and dry, it is used for thin soles worn inside boots and shoes. The shreds, mixed with indiarubber, are made into linoleum. LEAVES [(i) The lessons on Leaves are directed almost exclusively to the cultivation of the observing powers. (2) The matter provided will probably prove sufficient for five lessons, but the amount to be taken at once must necessarily depend on the time allotted to a lesson. (3) If not amply illustrated with actual leaves the lessons will be worse than useless. (4) It follows, therefore, that the lessons should be given while trees are in full leaf (5) The particular leaves suggested for illustration ha\e been selected because it is believed that they are all easy to procure. Should there be a. difficulty in finding any leaf named, another, having the same botanical peculiarity, should be substituted for it.] PARTS OF A LEAF [Give each child (i) Leaf with petiole and stipules, as apple. (2) Leaf with petiole but without stipules, as ivy. (3) Sessile leaf, as shepherd^s purse. (4) Wheat (not in ear) or grass. In the case of the first three the leaf should be on the stem, and in the case of the fourth the sheath should be present.] The blade. — Make children hold up apple leaf and point to the blade [lamina].^ 1 The technical terms are not to be taught. They are inserted for the sake of the teacher. Some of them have no simple name corresponding, and if only a simple name made up for these lessons were inserted there might be some doubt about its meaning. 1 iC) Longmans' Object Lessons Let them do the same with the ivy, shepherd's purse, and grass. Teach the term blade. The stalk. — Make children hold up apple leaf and point to the stalk {petiole). Do the same with the ivy. Let them hold up the leaf of the shepherd's purse. Ask children to show stalk. This will impress on them the absence of stalk. So with the wheat. Show that there is no stalk as in the apple and ivy, but that there is a sheath which takes its place. The leaf-scales {stipules). — Make children see that where the stalk of the apple leaf joins the stem there are two very small leaves. These are sometimes called leaf-scales. Then make them see that the stipules are wanting in the ivy and shepherd's purse. Fig. 20, — Leaf of Apple, with FiG. 21. — Shepherd's Purse, petiole and stipules. Fig. 22.— rt, split leaf-sheath of a Grass; b, ligule; c, node of the culm ; d part of the lamina. If the wheat (or other grass) has been well selected, the children will be able to see where the blade separates from the sheath a small scale {ligule) . Leaves 117 Parts of a leaf. — 'How many parts have we pointed out in the shepherd's purse ? ' ' What is it ? ' 'How many parts have we pointed out in the ivy ? ' ' What are they ? ' 'How many parts have we pointed out in the apple leaf? ' ' What are they V Every perfect leaf has those three parts. Make children see the modifications of two of them in the grass. VENATION AND FRAMEWORK [Give each child (i) Beech or other feather-veined leaf. (3) Maple or other palmate leaf. (3) Grass or other parallel-veined leaf.] Veins. — Let children look at beech leaf. They will see lines running along it. They will see them plainest on the under side. [Skeleton leaves, which may often be picked up in woods or ditches, would be useful here.] These lines are called veins. Let children point to veins in the maple leaf and the grass. Venation. — Next let them say what is the difference in the arrangement of the veins, (i) Between the grass and the other two ; (2) Between the beech and the maple. Teach them to call the grass straight-veined. \Parallel-veined is the botanical term, and it is just as easy as the other if the children learn drawing.] Hold up quill pen or other feather and the beech leaf. Show similarity of arrangement between barbs of feather and veins of leaf. Hence show fitness of term feather-veined. Hold up maple leaf with one hand. Beside it place the stretched-out fingers of the other hand. Make children see -Ciiiate leaf of the Beech. ii8 L onginans . Object L essons similarity, and hence the fitness of the term palm-veined (^palmate) . Recapitulation, — Produce a number of leaves different from those used hitherto, and question on their venation, which should be of the three kinds spoken of. Mid-rib. — Show line running down middle of beech leaf. It is a rib. When there is, as in this case, only one, it is called the mid-rib. Ribs. — Make children point out all the ribs in the maple leaf and see that there is no mid-rib. Fig. 24. — Reticulately veined \^&{ oi Acer sacckarinum. Veins. — Make children point out veins on beech and maple. Veinlets. — Let the children hold the leaves up to the light. Between the veins they will see finer lines. These are called ve inlets. Recapitulation. — As in the case of venation. SIMPLE AND COMPOUND LEAVES [Distribute specimens of various compound leaves, as ash, locust, horse-chestnut, poppy, clover, &c. Leaves 119 Also some simple leaf with bud at the angle where the stalk joins the stem (the axil) .] Simple leaf. — Show the simple leaf. Make the children see (i) That the green matter is continuous around the ribs. (2) That there is a bud in the axil. Compound leaf. — Show a compound leaf (ash or locust, say), and make the children see (i) That the green matter is not continuous around the ribs. (2) That there is a central stem with little leaves branching out on each side of it. (3) That there is no bud at the axil of these little leaves. The first kind of leaf is called simple, the second com- pound. The little leaves of the compound leaf are called <^^> Fig. 25. — Compound leaf of Locust, with opposite leaflets and spinous stipules. Fig. 26. — Compound leaf of Common Poppy. leaf-lets [compare with vein-lets\ j their stalks might be called stalk-lets {petiolule^. I20 Longmans' Object Lessons Some kinds of compound leaves. — Refer to feather-veined leaves. Ask children to pick out compound leaves with the leaflets similarly arranged (as locust). These are caW&A feather- like (^pinnate). Ask children to pick out compound leaves with leaflets ar- ranged like outstretched fingers (as horse-chestnut). These are called finger-like {digitate) . Then show other compound leaves, and call attention to the arrangement of the leaflets. Recapitulation. — Produce miscellaneous leaves. Ask chil- dren to divide them first into simple and compound ; then to classify the compound. SHAPES OF LEAVES [Get leaves of as many different forms as possible, including grass, arrow-wood, beech, oak, lettuce, holly, sycamore, geranium, Fig. 27. — Acerose leaves of the Scotch Fir. Fig. 28. — Lanceolate leaf of the Willow. dandelion, thistle, lilac, ash, nasturtium, radish, or other leaves hav- ing the same characteristics. Explain that you are going to divide them into classes. The classification '■ may be fourfold, depending upon J From the teacher's point of view the classi6cation of leaves is not of much importance, but getting children to use their eyes and to describe what they see is of great importance. Leaves 121 (i) General outline. (2) The margins. (3) Incision. (4) Apices. When any leaf is shown ask the children to pick out or name other leaves having the same characteristic] (i) General outline. — A few out of the great variety of out- lines may be shown. Dealing with leaves easily procured, we may show outlines which are — Sword-shaped (ensiform or linear), as grass. Needle-shaped {acerose), as pine. Lance-shaped {lanceolate), as willow. Shield-shaped {peltate), as nasturtium. Egg-shaped {ovate'), as a rose. Heart-shaped {cordate), as lilac. Hand-shaped {palmate), as maple or sycamore. Feather-shaped {pinnate), as ash. Lyre-shaped {lyrate), as radish. (2) Margin. — The margin may be smooth {entire), as in grass or iris. It may be tooth-like {dentate), as in the arrow-wood. Fig. 29. — Dentate leaf of Arrow-wood. Fig. 30. — Sinuate leaf of the Oak. Fig. 31. — Spiny leaf of the Holly. It may be hairy {ciliate), as in the beech (Fig. 23). It may have rather large hollows between rounded parts {sinuate), as in the oak. 122 Longmans' Object Lessons It may be crisped, as in the garden endive or curled dock. It may be spiny, as in the holly. (3) Incision. — This subject is rather too difficult for young children. Show them a few examples of incised leaves, as hop, sycamore, passion-flower, geranium, dandelion, thistle. Fig. 32. — Leaf of Dandelion. Fig. 33. — Leaf of Wild Geranium. (4) Apices. — The points of the leaves are of different shapes. Call attention to the points of the leaves produced, and make the children describe the shapes. EDIBLE LEAVES As a summary of the preceding lessons on Leaves a lessen may be given on Edible Leaves. Get from the children a list of the leaves eaten cooked, such as rhubarb, the many varieties of cabbage ; and the leaves eaten in salads, as lettuce, &c. Have specimens of each kind of leaf spoken of, and question as to its botanical characteristics. Ask for the blade, stalk, and Jeaf-scales, ribs, mid-rib, veins, veinlets, the venation and frame- Tea 1 23 work, margins, outline, &c. Also ask what other leaves with the same characteristics the children have seen. If drawing is taught, the outlines and venation of leaves should form subjects of two or three lessons. TEA Leaves. — Show the class some leaves that have been taken from a tea-pot and stuck on white card. The size and shape will thus be seen. Where grown. — ' On what did these leaves grow ? ' ' Whuh of you -has seen a tea-plant?' [No one. J 'Why not?' It grows in China, the North of India, and Ceylon. Show on the map. The shrub. — Show a picture. If there is not one in the school one can probably be obtained from some advertising tea-dealer. Faihng this, draw sketch on the blackboard with colored chalks. The shrub is an evergreen. ' What does that mean ? ' 'Name some evergi'eens that you know.' It is from three to six feet high. Show height. It would grow higher if it were not pruned. ' Why is it pncned? ' [To get more leaves and less wood.] To make this clear get out why a quickset hedge is frequently pruned. If the children have seen a myrtle say that the shrub resem- bles it. The leaves are of a bright deep green, and the flowers are a good deal like those of the japonica. The gathering. — The leaves are first gathered when the shrub is three years old. There are three gatherings in the year — in spring, summer, and autumn. Recall the fact that the shrub is an evergreen. The spring crop is the best, and the autumn crop the worst. The leaves are gathered one by one by people wearing gloves. ' Why are gloves worn ? ' Fold a piece of paper, place some juicy leaf between the folds, and squeeze ; then open the paper and show that the leaf is crushed and the juice gone. The 124 Longmans' Object Lessons tender tea-leaves might be crushed if gathered with the naked hand. The drying. — ' Who has turned over a heap of leaves ? ' Thence get out that the lower /eaves were rotting. If the tea- leaves were sent to this country as gathered they too would rot. The leaves are dried in a flat iron pan on the top of a kind of stove. Illustrate by drying some leaves on a hot shovel or other metal plate, and show that if they were not stirred they would shrivel up. When the leaves are hot they are poured on mats placed on a table. Then they are rubbed with the hands in one direction to make them curl. Illustrate with the leaves already dried. Show some tea, and let children note similarity. The roasting and rubbing are repeated several times till all the moisture has gone. Then they are ready for use. Kinds. — 'How many kinds of tea do you know of?' The black tea consists of the older leaves. They are placed in a heap after they are gathered, till the heat thus formed darkens them. [If the lesson is given to rural children compare to the ' heat ' of a new hay-stack, and call attention to the difference in color between grass and hay.J Green tea consists of the younger leaves dried and rolled as soon as gathered. Poor kinds are dyed. TOBACCO [Tobacco is often grown as an ornamental plant. If the teacher knows any garden where it is so grown he should procure a leaf or two. A dried leaf can be obtained at a tobacconist's.] Forms. — Show the leaves, and say what they are. (i) The leaves are cut for smoking in pipes and cigarettes. (2) They are folded for smoking as cigars. (3) Certain parts of them are dried and ground for snuff. Where grown. — Tobacco was first brought from America, where it is still largely grown. It will grow in any country Tobacco 125 where they do not have sharp frosts. 'What would frost do to it?' Growth. — Cornpare the first stages in the cultivation of the tobacco plant to the first stages in the cultivation of cabbages. The seeds are set in hot-beds. When the plants are about four inches high they are transplanted. 'Why?' [For hght, air, and room to grow.J Till the warm weather comes they are covered at night. ' Why ? ' The fields are carefully weeded. Decaying leaves are plucked off. The flower is also cut off. Explain that this gives greater strength to the leaves. Harvesting. — When the leaves become of a yellowish-green they are ready to be harvested. The plants are cut close to the ground, and bung up in barns for about a month to dry. Then they are piled in a heap to sweat. The leaves are now tied into bundles called hands, packed in hogsheads, and sent to the place where they are to be prepared for use. [The details of the manufacture can be ignored.] Moral. — Many people believe that tobacco is harmful to everybody. There can be no doubt that it is very harmful to all persons who are not full grown. THIRD YEAR. A : Lessons on Elementary Chemistry and Physics OXYGEN [Hints to the teacher. — Oxygen may be made by heating chlo- rate of potash (potassium chlorate) or black oxide of manganese (manganese di-oxide) ; but it is best prepared for experimental pur- poses by using a mixture containing about equal weights of the two substances, as the gas comes off at a much lower temperature than when either is used alone. Place the mixture in a flask (as shown in the following cut) or in a glass retort. The flask must be provided with a cork through which a bent glass tube passes. Nearly fill a pneumatic trough with water, and above each hole in the shelf of the trough place an inverted jar filled with water. Fig. 34. Place the bent end of the delivery tube under water (not under any of the jars), and apply hep.t to the flask. The bubbles at first given off consist of the air driven out by expansion. When all the air has come off, place the tube under the first jar. When that is full, place the tube under the second jar. While that is filling, cover the mouth of the first (underwater) with a gi eased glass disc. Proceed thus till as many jars are provided as will be required. 126 Oxygen 127 Half-pint flasks for this purpose are sold by dealers in chemical glassware for a few cents each . Rubber stoppers to fit the mouth of the flask, already perforated with one or two holes for delivery tubes, can be procured from the same source. The best way to bend glass tubing is to hold' it horizontally in a gas-flame from an ordinary burner the long way of the flame. Fig. 35. Keep twisting it round till it begins to soften, and then let it bend over to the right shape by its own weight. To cut glass tubing make a notch in it with the triangular file, then bend it away from the notch, pulling at the same time. The sharp edges can be rounded off by making them red-hot. If the teacher has no proper gas-jars, large-mouthed glass fruit or pickle bottles will do very well instead. A test-tube may very well be substituted for the flask. A tables spoonful of the mixed powders will produce oxygen enough to fill several bottles. Fig. 36. Failing any form of pneumatic trough, a flat-bottomed pan may be used. The risk of breaking the flask may be reduced if the mixture is first warmed gently at the top, and the flame is brought gradually dowmvard as the gas begins to be given off. 128 Longmans Object Lessons As soon as the jars of gas are full, lift the end of the delivery tube out of the trough. Otherwise, as the hot gas cools and con- tracts, the water will rush up the tube and crack the flask.] A gas. — If the school-room is provided with illuminating •gas, open a stopcock, but do not light the gas. ' What is coming out here ? ' There are many different kinds of gas, and this is called ' coal-gas.' ^ 'Can you see it ?' 'Can you smell it?'' ' Can you feel it V (Only when it is in motion.) 'Will it burn ? ' Light it for a moment. But for the little coal-gas now in it, the room is full of other gases. ' Can you see them ? ' 'Smell them i ' 'Feel them ? ' ' Will they burn ? ' Light a match to show that they will not. These gases together make up the air. One of them is called oxygen. Some properties of oxygen. — Show the jars containing oxygen. Warm the oxygen mixture a little, and let the gas escape into the air. Apply a match to the end of the delivery tube. The gas will not burn. Tell the children about some people being suffocated while sleeping in a room into which coal-gas was escaping. That proved that we cannot breathe coal-gas. We can breathe oxygen ; in fact, we should very soon die if we had none to breathe. Things burn in oxygen. — Many experiments can be per- formed to show that things burn in oxygen better than they do in air. (i) Light a splint of wood. Blow out the flame, but leave a glowing spark. On being dipped into a jar containing oxygen this spark bursts out into a flame. (2) Show that it is difiScult to burn charcoal in air. Then put a piece on a deflagrating spoon, as in Fig. 37 ; ignite, and place in the oxygen. The charcoal will at once glow brightly and throw off briUiant sparks. [A piece of wire, one end of 1 If illuminating gas is not present, put a few drops of gasolene, benzine, or ether in a wide-mouth bottle or tumbler. Cover the vessel and let it stand a few moments. The liquid will soon evaporate and fill the vessel with a com- bustible vapor which may be treated as the ' coal-gas.' Oxygen 129 which is passed through a cork and the other twisted around the charcoal, will do instead of a deflagrating spoon.] Fig. 37. Fig. 38. (3) Burn sulphur similarly in air and in oxygen. (4) Show that a piece of iron wire will become red-hot in air, but will not burn. Wind thread four or five times around the end of a straightened watch-spring, and saturate it with melted sulphur. Ignite, and dip it into a large jar containing oxygen, and the iron itself will burn brilliantly (Fig. 38). Other similar experiments may be performed if the apparatus and materials are available, but the teacher must take care to impress upon the children the truth which the experiments illustrate. Things will not burn without oxygen. — Things burn in the air because of the oxygen in it. As they burn they use up the oxygen, and when it is all used they go out. Stand a lighted candle in a shallow dish. Over it place a bottle or Jar, and pour into the dish enough water to cover the mouth of the jar or bottle, and thus prevent the entrance of air. When the candle has used up all the oxygen it will go out. If instead of the bottle we had a bell-jar (as in Fig. 39), we could lift the stopper and re-light the candle. Then if we Fig. 39. I30 Longmans Object Lessons admitted air below by means of a tube, the candle would con- tinue to burn. [A fruit or pickle-bottle from which the bottom has been reaioved is a satisfactory substitute for a bell-jar.J NITROGEN Review the last lesson so far as may be necessary to re- impress on the children's minds — ( 1 ) That the air is almost entirely made up of two gases. (2) That oxygen is one of these. (3) That some of the oxygen is used up when anything is burned. Nitrogen. — [For the success of this lesson a bell-jar (or some such substitute for one as was suggested at the end of the preceding lesson) is essential.] Take a piece of phosphorus about as large as a pea ; dry it with blotting-paper, and then place it on a large piece of cork ' floating in a shallow dish con- taining a little water. Cover with a bell-jar. Remove the stopper, ignite the phosphorus with a piece of red-hot wire, and immediately replace the stopper. The jar will be filled with dense white fumes. When these have settled it will be seen, if the stopper is air tight, that the water has risen some way in the jar. Measure, and prove that it has risen one-fifth. ' With what was the jar jilted at jirst? ' 'And oj how many gases was this air made up?' ' What is the name oj one oj them ? ' ' What became oj this as the phosphorus burned? ' ' Why did the phosphorus go out? ' 'How many gases are there now lejt in the jar? ' ' What took the place oj the oxygen ? ' The other gas is called nitrogen, and it forms four- fifths of the air. Properties. — Pour water into the vessel till it reaches the level of that inside the jar. Place a small 1 It !s well to prevent the cork from burning by putting between it and tjie phosphorus a little piece of mica or glass or chaljt. Otherwise the nitrogen may be clouded with smolce. Carbonic Acid Gas 131 lighted taper in the nitrogen. It at once goes out, thus show- ing that things will not burn in nitrogen. Contrast the properties of oxygen and nitrogen. Remind the children of the great rapidity with which things burned in oxygen. Hence elicit the Use of nitrogen. If the air were made up of oxygen alone it would be too strong for us to breathe. We should be used up too fast somewhat as things are burned up in it alone. Hence the necessity for 'diluting' the oxygen with nitrogen. Compare to the way in which mother adds water to tea which is too strong. CARBONIC ACID GAS^ [The apparatus required for the preparation of carbonic acid gas is shown in Fig. 41. An ordinary fruit or pickle bottle will do, if fitted with a large cork. In the bottle place small pieces of chalk, limestone, marble, or any other carbonate. To this add hydrochloric or some other acid.] Properties. — (i) Dip a burning taper or candle into a jar containing the gas. The light ^l will go out. This proves that ^' things will not burn in it. (2) Take a jar containing only air. To show that it con- tains air place a lighted candle in it. Pour into it the carbonic acid gas, and prove that you have done so by again placing the lighted candle in. This shows that carbonic acid is heavier than air — which also is proved by the method of collecting the gas. (3) Pour a little lime-water 1^ Fig. 41. * into a jar. introduce some 1 The name which chemists now give this gas is carbdn di-oxide. This has the merit of indicating the composition, COj. 2 If lime-water cannot be readily procured, prepare some by putting a piece 132 Longmans Object Lessons gas into the water, which turns milky. Make the children note this carefully, as this is the test for carbonic acid. We breathe out carbonic acid gas. — Let some of the chil- dren breathe through a tube into some lime-water, which will become milky. ' What does this show ? ' There is a little carbonic acid gas in the air. — The experi- mental proof of this cannot be performed in the course of a lesson. If some lime-water be exposed to the air for a day a thin iilm will form on the top, and in a few days it will be milky. This proves that the air contains the gas, but contains very little. It really forms four parts out of 10,000. Carbonic acid gas" is formed when things' burn. — Place a candle in a bottle containing air. When the candle has gone out,^ pour a little lime-water in and shake it up. It turns milky. Food for plants. — Plants help to purify the air, because they take from it and use for food the carbon or carbonic acid [^What remains ?'~\, and they give out oxygen. (See p. 222.) HYDROGEN [How to prepare . — Hydrogen is generally prepared in a Woulffe's bottle, as shown in Fig. 42. If there is not one available use a wide-mouthed bottle, and bore two holes in the cork, one for the thistle funnel and the other for the delivery tube. The whole apparatus must be made air-tight. Place in the bottle about an ounce of zinc cuttings or zinc nails. Cover them with water. Then through the thistle funnel, pour in a little sulphuric acid, and hydrogen is given off through the delivery tube. Keep the apparatus at a distance from any flame. [See (2) below.] of common lime about the size of a hen's egg in a quart of water, allowing it to remain there three or four hours, and then filtering the liquid through filter- paper placed in a funnel. 1 Things which contain carbon, as all our fiiels do. It is not formed when phosphorus, sulphur, and many other things burn because they do not con- tain carbon. 2 As it must in a little while for two reasons, (i) because it will consume the oxygen, and it cannot burn upon the nitrogen which is left, and (2) because it will produce carbon di-oxide which must extinguish the fiame. A Burning Candle 133 Properties. — (i) We collect the gas by placing a test-tube over the delivery tube. Make the children see that this shows the gas is lighter than air. It is the lightest gas known. A small balloon made of gold-beaters' skin will rise if filled with hy- drogen. (2) Fill a test-tube with hy- drogen. Apply a light. There is a loud explosion and the gas burns. A mixture of hydrogen and oxygen, or of hydrogen and air, is explosive. (3) After the last experiment look at the tube. Its sides are wet. The burned hydrogen and 'ic 42. the oxygen necessary for burning it formed water. Water con- sists of one part of oxygen and two of hydrogen.' A BURNING CANDLE What does not burn. — Light the candle. 'Of how many parts is this candle made up ?' ' IVhich of them is burning ? ' Apply a hght to fat without wick and to wick without fat, and thus show — (i) That the fat will not burn at all, and (2) That the wick burns badly for a very short time and then goes out. What does burn. — Place a little fat in an evaporating-dish or watch-glass ; warm till vapor arises, then light the vapor. ' What is burning ? ' Light the candle. Blow it out. Apply a match to the smoky vapor arising, being careful that the match shall not 1 The fact that the two gases must be chemically, not mechanically, combined, may be ignored at present. 134 Longmans' Object Lessons touch the wiok. The vapor will light and communicate flame to wick. When a candle is first lighted the heat of the burning wick forms a little cup containing melted fat. The wick sucks up this, fat, which the heat changes into vapor that burns. 'Why does a candle, when first lighted, nearly go out sometimes, and then flame up suddenly ? ' The flame. — Place lighted candle under tumbler or other glass vessel. Candle goes out. ' Why ? ' Burning goes on only in contact with oxygen. The flame is therefore hollow. The shape of the flame will best be seen if a lamp chimney is placed over the candle. The glass must be so placed as to admit air below, or the candle will go out. To show that the flame is hollow take a piece of white paper ; hold it, with the surface horizontal, in the middle of the flame ; remove before ignition takes place ; rub off the soot, and a scorched circle will be seen. The hollow of the flame is filled with gas which will burn. Hold the lower end of a glass tube very steadily in the flame ; apply a light to the other end, and the gas from the hollow of the flame will rise up through the tube and burn at the upper end. What becomes of the candle. — The fat of the candle is made up chiefly of hydrogen and carbon. The hydrogen uniting with the oxygen of the air forms water. Hold a glass vessel over the flame, and water will be depos- ited on the sides. The vessel must not be held too long or the heat of the candle will dry up the water. The carbon of the candle uniting with the oxygen of the air forms carbonic acid gas. Show this by letting the candle burn out under an inverted fruit jar or other glass vessel, and then pouring a little lime-water into the vessel and shake. The bright part of the flame consists of burning carbon. Some of this carbon is given off as soot. Show. The ' smoke ' consists of particles of carbon. Matches 135 MATCHES Tinder. — Before matches were invented there were other ways of getting a light. One was the tinder-box. Prepare some tinder, and procure a piece of flint and a piece of steel. [The back of a pocket-knife will do well for the steel.] Strike sparks, and let them fall on the tinder. Show that it will glow, but not flame. Sulphur matches. — The difficulty of obtaining a flame was got over by touching the glowing tinder with something that would easily light, such as a sulphur match. Prepare sulphur matches by melting a little sulphur and dip- ping into it the ends of dry splints of wood. [The wood of ordinary matches will do.]" Touch the glowing tinder with one of the sulphur matches. Chlorate of potash and sugar. — Matches were also made by dipping the ends of splints into a mixture of chlorate of potash, sugar, and gum. ' Why gum ? ' [To make the mixture stick to the wood.] Prepare matches as described, or drop a little sulphuric acid on a mixture of powdered chlorate of potash and sugar. The matches were lit by dipping them into sulphuric acid. Phosphorus. — These methods of getting a light fell out of use when phosphorus matches were invented. Friction causes heat, and the heat, if great enough, causes flame. (i) Let a child rub a brass button on the desk. 'What makes the button hot i ' (2) 'When a train is going very quickly the wheels or axles sometimes get on fire. Why i ' (3) 'I/ow do savages get a light ? ' Phosphorus lights with a little heat. — Show bottle contain- ing phosphorus. ' What is the liquid in the bottle ? ' [Water.] 'Why has the phosphorus to be kept under water? ' 'Why do we rub a match ? ' [The friction gives heat enough to make the phosphorus light.] 136 Longmans' Object Lessons Phosphorus matches. — The heads of matches are now gener- ally made of a mixture of phosphorus, chlorate of potash, sugar, gum [' Why gum ? '] and coloring matter. Safety matches. — Rub an ordinary match on anything rough. '■What causes it to light V [The phosphorus.] Rub a safety match. ' Why will it not light?'' [There is no phosphorus in it.] Rub it on its own box. It lights because there is a little of a kind of phosphorus on the box. Rubbing causes enough heat to make the phosphorus light the match, though not enough to light the phosphorus itself Let a child feel that the box is warm immediately after being used. Prepare ' touch-paper ' by steeping brown paper in a solu- tion of nitre and then drying well. Show the paper will glow, but not flame. Speak of fuses. ' Why is it necessary that they should burn slowly ? ' COAL-GAS How obtained. — Fill the bowl of a clay pipe with coal-dust,^ cover the top carefully with well-kneaded clay, then place in a clear fire. At first, what looks like dense smoke will come through the stem. This is chiefly steam. Then will come off gas which can be lighted. Another way is to heat coal-dust in a small flask made of hard glass, and to collect the gas over water. When the manufacture is conducted on a large scale, the coal is heated in retorts of iron or fire-clay, and the gas is purified before passing into the gas-holder where it is stored. Properties. — These may be demonstrated from the gas in the pipes of the building. (i) Coal-gas will burn. (2) It has a disagreeable smell. (3) It cannot be breathed. Refer to cases where persons have been suffocated by an escape of gas into the room in which they were sleeping. 1 It must be soft or bituminous coal. Coal-Gas 137 (4) Mixed with air it explodes. Show that the pure gas will not explode — it only burns. When there is an ' escape ' the gas mixes with the air, and when certain proportions are reached . an explosion is produced if the mixture is lighted. Explosions often occur in mines from this cause. Safety-lamp. — To prevent these a safety-lamp is used. Turn on the gas without lighting it. Over the escaping gas hold a Fig. 44. piece oi fine wire gauze.^ Apply a light above the gauze. The flame will not pass through -it to the burner. In a safety-lamp the flame is surrounded by fine wire gauze. By reference to experiment show the action of the lamp. Caution. — Never seek for an escape with a light. When there is a smell of gas in a room, open doors and windows wide. ^ About 30 meshes to the inch. 138 Longmans' Object Lessons Coke. — Break the bowl of the pipe used at the beginning of the lesson. Show the coke which has been formed. Also show coal, and compare the qualities. 'Why does coke burn with little flame ? ' VENTILATION Oxygen necessary in respiration. — Refer to the Black Hole of Calcutta, and explain that the people confined in it died through lack of oxygen. Also that a small amount of some- thing which produces a fetid odor in an unventilated room comes from lungs and skin. This is believed to be an active poison. Carbon di-oxide is no longer considered poisonous, but when it takes the place of oxygen to any large extent, life is destroyed by oxygen starvation. Products of combustion. — We saw (p. 137) that carbonic acid gas is made when things burn. But burning things also give off tiny particles of carbon or soot. When a fire is first lit, or when it is smoking, we can see large quantities given oif, but the particles are also given off when we cannot see them. Hold over a lighted lamp or candle, too far off to char it, a piece of clean paper, and show the discoloration which imme- diately takes place. ' What caused the blackness ? ' ' Why are: ceilings often black ? ' Recapitulate and emphasize the cardinal facts — (i) That living creatures poison the air of a room. (2) That a lamp, a candle, or gas vitiates the air ; and hence show the need for getting the impure air out of rooms and pure: air in. Hot air rises. — Light a lamp which has a chimney. Let the children feel the hot air coming out at the top. Over the top hold a piece of smouldering brown paper. ' Which way does the smoke go ?' ' Why does it rise ? ' ' Why do smoky flames blacken the ceiling and not the walls ? ' Get a wide-necked bottle, such as a jam or pickle bottle. Into the neck fit a cork with holes bored in it for two large tubes. In the bottle place a short piece of lighted taper^ Ventilation 139 l >yALi-| Push the lower end of one glass tube down nearly to the bot- tom of the bottle, and let the lower end of the other tube be near the top. The hot air rises to the top of the bottle, and goes out through the upper tube. To prove this, hold a piece of smouldering paper above the tube, and the smoke will rise. Hold the paper over the other tube, and the smoke goes down and through it. 'What does that prove ? ' Insist on the two principles here illustrated, as they involve the theory of ventilation and of winds also. Ventilation. — ^The air in a room could be easily changed by having one opening near the top for the hot, impure air to go out, and one near the bottom for the cold, pure air to come in. Open the door an inch or two if it leads to a room or passage colder than the class-room. Hold a lighted candle near the /^ Fig. 46. Fig. 47. " Fig. 48.— Tobin pipe. top and the flame will be biown outward ; hold the candle near the floor and the flame will be blown in. This shows the direc- tion of the air currents above and below. 140 Longmam Object Lessons Let the children feel the cold air coming in below. They will then appreciate the objection to ventilating a room by openings near the floor — the draught caused. If an opening is made above people's heads straight through the wall into the open air, the cold air will pour in and fall down in a stream a short distance from the opening (Fig. 46). Hence elicit the necessity of giving the incoming air an up- ward direction, so that it shall come down like a fountain, after being warmed by the air near the top of the room. This is done in several ways — e.g. — (i) By raising the lower sash of a window and placing a board right across the lower opening. The air thus enters between the two sashes, and is directed upward by the top of the lower one (Fig. 47). (2) By fixing a cold-air register. Fig. 48 shows the action of this. There are many other ways, but these two show the prin- ciples applied in ventilation. WINDS Hot air rises. — Repeat the experiment performed last lesson (p. 138) of burning a candle in a bottle fitted with two tubes, and emphasize the truths it illustrates — (i) Hot air rises. (2) Cool air flows in to take its place. Further illustrate the same truths by reference to a fire in a grate. When the fire is lit it begins to warm the air around it. This air goes up the chimney, carrying the particles of smoke with it. Cold air from the room then flows in underneath the grate. ' Why is the grate raised above the ground? ' The sun is to the air of the whole earth what a fire is to the air in a room. The sun heats some portions of the earth more than others. The air from the colder regions being heavier presses in and buoys up the air of the warmer regions. These movements of the air are called Winds. Aain and Snow 141 Land and sea-breezes. — The effect of the sun in causing winds may often be noticed at the sea-side in summer. In the morning a breeze will be felt blowing towards the sea, and in the evening a breeze from the sea. The land gets hot much sooner than the water. The stones on the beach will on a sunny day be almost too hot to touch, while the sea will be pleasant to bathe in. On the other hand, the water keeps its heat much longer than the land. Towards evening the land will have heated the air above it so much as to make currents set in from the sea. At night, however, the land rapidly loses its heat, so that in the morning the air over the water is the warmer, and currents blow towards the sea. Trade winds. — Show a globe. Ask the children to point to the warmest part of the earth and the coldest parts. Make them see that the air at the equator must rise, and the air from the poles must flow in to take its place. Hence we should expect winds towards the equator from either pole, but, for causes which it may be best in some classes to attempt to explain, these winds are changed to an easterly or westerly direction in certain zones, and because sailors can always count on them they are very useful for trade, and are therefore called the Trade Winds. Constant winds can beexpected only when there is constant heat in the same part of the earth. There can be no constant winds in the British Isles, for example, because the temperature of the neighboring seas and countries varies so much that currents will be blowing sometimes in one direction and some- times in another. RAIN AND SNOW Evaporation. — Warm some water in a test-tube. 'What is this above the mouth of the tube ? ' [Vapor or steam.] ' Where does it come from ? ' Thus, though we cannot see it, there is some in the tube. Hold a lighted vapor in the visible vapor, 142 Longmans' Object Lessons and it then becomes invisible. Hence elicit that we can see vapor only when it is beginning to cool. If steam be watched coming out of the spout of a kettle a small space near the spout will be noticed with no visible steam. Ask the children to explain this. Condensation. — Over the vapor issuing from the test-tube hold a cold slate. Show the condensation into large drops of water. Then emphasize the three facts — (i) Heat changes water into vapor. (2) Cold changes the vapor back into water. (3) Vapor becomes visible as it begins to cool. The sun causes vapor to rfse from the oceans, seas, lakes, rivers, and other pieces of water on the face of the earth. Fig. 49. After a shower we say that the water on the road ' dries up.' ' What becomes of it?' Mist, fog, clouds. — When the vapor in the air touches the cold sides of hills or mountains, or when it comes against a cold current of air, it begins to condense. If it condenses Frogs and Toads 143 near the ground we call it mist or fog, and when high in the air clouds. Rain. — When the air charged with vapor is carried into the upper regions of the atmosphere, it expands. The expansion of moist gases always chills them and produces a mist. (Uncork a ' soda-water ' bottle and notice the mist which forms around its mouth.) This, together with the fact that the upper atmos- phere is always cold, produces rapid condensation of moisture. If condensation goes on after the cloud is formed, the small particles of water gather more moisture around them till at last they are too heavy to remain in the air, and fall to the ground as rain- drops. Snow. — When the air is cold enough the falling moisture may be frozen into snow flakes. B : Lessons on Animals FROGS AND TOADS [This lesson should be given at a season when it can be illus- trated with a living frog or toad. If given in the spring it should also be illustrated with spawn and tadpoles.] Cold-blooded. — Let children feel the frog or toad, so that they can perceive that it is cold. ' Is it colder than the water in which it has been kept?' Question as to the differences perceived in feeling (say) cat, dog, hen, hare on the one hand, and fish and frog on the other. The cat, dog, hen, and hare are warm-blooded, and need coverings to keep in the heat of the body ; the fish and frog are cold-blooded, i.e. their blood takes the temperature of surrounding objects, and need ijo such coverings. Fish and reptiles. — 'Frogs, fish, and reptiles are alike in being ? ' [Cold-blooded.] They differ in their way of breathing. Fish breathe by means of gills. Reptiles breathe by means of lungs. Fish and reptiles both lay eggs \^spa7nn^ which are hatched by the heat of the suxr. 144 Longmans Object Lessons Frogs and toads at first live the life of a fish, and afterwards that of a reptile. Development. — The eggs are laid in the water. At first they are very small, but they soon swell to the size of a pea, and a mass of white jelly forms around them. [If possible show spawn.] When the egg has been in the water for some time it breaks, and a little creature with a large head, long flat tail, and no body comes out. (Fig. 50, in.) This is called a tadpole} It swims just like a fish, by moving its tail from side to side. It also breathes like a fish, by means of gills, which are at first small tufts of threads on each side of the head. (Fig. 50, ni, ex. br.) When the tadpole is full-grown the gills become small, and at last disappear. By this time lungs have grown in the chest, so that the creature can breathe in the air and not in the water. Then the body grows large and the tail shrinks. Finally, four legs grow out of the body, the tadpole has be- come a frog or toad. The toad may be distinguished from the frog by its warty and thick body and by its habit of living upon the land, except in the spring when 1 A tadpole is literally a ioad-poU—a. toad which is nearly all/o// or head. Ir.i.. Fig 50. — Stages in development of Tadpole. Frogs and Toads MS it goes to the water to lay its eggs. It passes through the tad- pole stage in a few weeks, while the frog requires two seasons for its development. The common frog has a slender body with smooth skin, and remains in and about the water after its development is completed. Structure of frogs and toads. — Legs. — The front legs are short ; the hind legs strong and very long. Ask for other ani- mals with long hind legs, such as kangaroo, hare, rabbit, grey- hound. Show that these, like the frog, can jump well. The hind legs of frogs are frequently eaten. Feet. — -Webbed. In frogs more so than in toads. 'IV/ty?' Ask for other creatures with webbed feet, and show that, like the frog, they can swim well. Tongue. — Frogs and toads live on worms, grubs, and flies. Hence toads are very useful in a garden. The mouth is very wide, and the tongue, which is long and thin, is fixed near the front of the jaw, with its tip di- rected backwards. The tip is always covered with a sticky substance. The toad darts out its tongue, the fly or other insect sticks to it, and is drawn in very quickly. £yes. — Large ; formed for seeing in the dark. ' IVAy is this useful? ' SAin.— The skin of the ^'°- si.-Skeieton of Frog, frog is very porous and requires to be kept moist, as it shrinks rapidly if dry. Breathing takes place partly through the skin. The skin of the toad is warty and dry. The winter. — Elicit that as there are no worms, grubs, or flies to be found in winter, the frogs and toads must either go to a warmer country, like the swallow, or sleep, like the bear. They sleep. They find out a hole in a small cave, or under a big stone, or bury themselves in the mud, and there pass the cold months. 146 Longmans' Object Lessons THE CROCODILE [The lizard resembles in many respects a miniature crocodile ; one would be useful for illustration. Have also a good picture. The differences between the crocodile and the alligator can be ignored.] Where found. — The crocodile is found in the Nile, the Ganges, and other large rivers of Africa and India. A kind of crocodile called the alligator is found in the large rivers in the hottest parts of America. Size. — The crocodile is the largest reptile now found in the world. From 16 to 18 feet long is a common size, but some have been known 30 feet long. Make these measurements concrete. A large crocodile weighs as much as an elephant. Color. — A crocodile lying on the water escapes notice be- cause its shape and color make it look like a floating tree- trunk or big log. Compare this ' protective coloring ' to that of the lion (sand) and of the tiger (jungle grass). Skin. — The skin of the upper part of the body is covered with thick horny scales. These are so hard that no sword can cut or spear pierce them, and bullets are sometimes flattened against them. The skin under the body is softer. Savages use the skin for shields and armor. Tails. — ^The tail is very long and powerful, and by means of it the animal can move very quickly in the water. Legs. — The legs are short. In the water they are used to balance the body. When angry the crocodile moves quickly on land, but its great length causes it to turn slowly, and the creature that it is chasing can escape by going zig-zag. Illus- trate on the blackboard. If the stream in which a crocodile is living dries up [Ask about the climate of the countries where it is found], the crea- ture sometimes walks over land in search of water, but its feet are soon cut and wounded so that it can hardly crawl. Some- times it merely buries itself in the mud of the river-bed and sleeps till the next rainy season. If the weather is very hot The Crocodile I47 and dry the mud becomes as hard as brick, SO that the croco- dile cannot move. The natives then come and kill it at their ease. Teeth and food. — Make the children observe the great length of the jaws, and the sharp, pointed teeth with which each is armed. Hence elicit that the crocodile is a flesh-eater. It feeds on fish, on the animals which come to the river to drink, and on any living thing that it can catch — sometimes on men. Throat, nostrils, and mode of catching prey.— The croco- dile, lurking under the bank, sweeps into the water with a blow from its strong tail any creature that may come to the river- side. The crocodile then seizes the creature with its jaws and holds it under water till drowned. The crocodile itself would be drowned if water got into its lungs, but this is prevented ( 1 ) By the position of the nostrils. They are placed at the end of the snout, which is very long, so that they are above water while the prey is under. (2) There is a kind of leathery flap in the throat, and this acts as a trap-door, keeping out the water which must enter the mouth. Eggs. — The crocodile lays eggs which, notwithstanding its size, are not bigger than a goose's. It buries them in the sand ['To be hatched by ? '], but stays near to watch them. The natives, knowing this, hide near and wait till it is asleep, when they kill it. Fortunately, several creatures are fond of the crocodile's eggs. One, sometimes called ' Pharaoh's rat ' [the ichneumon], eats a very large number of them. The young crocodiles are only a few inches long. Compare to lizard. As soon as they are hatched they run to the water, where they will snap and bite as fiercely as if they were full- grown. 148 Longmans' Object Lessons SNAKES Structure. — Let the children feel their own spines. The spine or ' backbone ' consists of a number of separate bones ->S.ag^ "="- Fig. 52. joined together. These bones run through the whole length of the snake. Let the children feel their ribs, and make them note that all the ribs are joined behind to the spine, and that some are joined in front to the breastbone. Snakes have no breastbone. Most of the bones of the spine have each a pair of ribs all free in front. These ribs can be moved backwards and forwards at will. Snakes have no legs. Still they glide and swim and leap, but it is difficult to understand how they do these things. The skin of the snake is covered with scales. Snakes 149 How snakes swallow. — Each jaw has a large number of small, very sharp teeth, all pointing backward. These teeth are used not for biting but for holding. The jaws are pushed forward and then drawn back, and the prey is thus brought further and further in. Snakes can swallow things much thicker than themselves, because (i) The bones of the jaw are not joined together. They are simply held in their place by the skin, which is as elastic as indiarubber. (2) The ribs do not meet in front, and the skin of the body is also elastic. Thus the middle part of a snake's body may often be seen bulging out, showing the shape of some animal that has been swallowed. Poisonous snakes. — Snakes that are not poisonous live on Fig. S3, — Poison fangs, showing internal hollows, a, superficial view; Af longitudinal section; c, tooth of hydiophis, with open poison groove. creatures having no means of defence, such as frogs, which, when once caught, can be easily swallowed ; but poisonous snakes live on mice, which would bite, and on birds, which 150 Longmans Object Lessons would flap their wings. These snakes therefore poison. their prey before swallowing. Poisonous snakes have no sting, but in the front of the upper jaw they have two long, sharp, curved teeth called the poison fangs. When the mouth is closed these lie against the upper jaw, but when the mouth is open they project, with the point backward. They are hollow, and at their root is a kind of large bag filled with poison. In the act of striking, the muscles which close the jaws squeeze this bag and drive the poison through the fang into the wound. Fig. 54. — Poison apparatus of Rattlesnake, a, poison bag and duct; *, i, g, ti If, muscles of jaw. Tongue. — A snake's tongue is small and forked. It is used for feeling, not for stinging. TB£ BUTTERFLY [The school museum probably contains specimens of the chrys- alis and of various butterflies. If the lesson is given in the summer there will be no diificulty in illustrating it with butterflies and cater- pillars. A large picture is also necessary.] Food. — Butterflies live on the juices of flowers. Hence elicit that (i) We see butterflies only in warm weather, when flowers are plentiful. The Butterfly 151 (2) They need no teeth. (3) They must have suckers. (4) They must be able to fly. Sucker. — The butterfly has no mouth or teeth. 'Why?' Instead of them it has a long trunk or sucker, which, when not in use, is coiled like a watch-spring under the head. This is divided into two parts by a slit down the middle, each part being grooved. They have tiny hairs all the way down, and the two parts are made into one tube by the interlacing of these hairs. Compare to the union which can be effected between two blacking-brushes by striking them smartly together. These hairs keep back any particles which might be mixed with the juice. After a meal the two parts of the sucker are separated, and the two front legs are employed in cleaning them. Feelers. — In front of the head is a pair of feelers. [The technical name, palpi, need not be given. The same remark applies to the other technical terms that occur.] They can be pushed out or drawn in at pleasure. Compare to snails. Horns (antennae). — These stand out from the front of the head, and each ends in a small knob. We can tell a butterfly from a moth by the fact that the antennae of the moth have no knobs. The use of the horns is not certainly known, but when they are cut off the insect cannot fly. Eyes. — On each side of the head a large eye stands out like a bead. When seen through a good microscope its surface appears somewhat like that of the honeycomb in Fig. 56. This is called a compound eye, for it contains many hundred six- sided cells each holding a single eye which is supposed to see. On the top of the head, half buried in down and scales, is another pair of eyes, much smaller than the first. Legs. — Like all other insects the butterfly has six legs. These are fastened to the chest. The front pair is small ; use already given. The other pairs are seldom used for walking, but for resting the body while the juice is sucked from flowers. Wings. — Four. Show the beautiful colors. ' What have you noticed on your fingers after you have been holding a butterfly?'' This dust consists of little scales. They lie one over the other 152 Longmans' Object Lessons like the tiles on a roof, and they are of many different colors. When they are rubbed away there are Uttle black spots show- ing where they have been. Eggs. — The butterfly lays eggs and then dies. The eggs are laid upon a leaf of the plant upon which the caterpillar that comes out of them feeds. They are fastened to the leaf by a kind of glue. Caterpillar (larva). — When the sun is warm enough it hatches the egg, out of which comes a little caterpillar or grub. This little creature at once begins to eat, first its own shell, and then the leaves around. In twenty- four hours it eats more than twice its own weight. Eating so much it grows very fast, and its skin gets too small. The skin cracks, the caterpillar comes out with another, and once more begins to eat. This happens four or five times. Pupa or chrysalis. — Then the caterpillar finds that it cannot eat any more. It fastens itself up to a leaf, or a twig, or a wall, by means of threads Pj^ '' which it spins. Compare to a spider's web. The Caterpillar. gkin shrivels, and a very strange-looking creature comes out. Show chrysalis or picture of one. It now seems quite dead, and remains in this state till the warm weather. Then the shell bursts, and out comes the perfect butterfly. THE BEE [Illustrate with large picture, a few dead bees, honeycomb, wax, and honey.] Wild and hive bees. — In different parts of the world there are wild bees, which live in hollow trees or holes in the rock, but the honey and wax are so useful that in civilized countries bees are kept in hives. Cells. — ^The first thing bees do after being placed in a hive is to make ' honeycomb.' One bee hangs from the roof and others hang to her. From six little pockets in their bodieg The Bee IS3 they squeeze out wax, which they knead with their teeth and form into six-sitied cells'. Show honeycomb. Also draw, an^ demonstrate that with hexagonal cells no space is wasted. Fig. 56. Kinds. — In each hive there are three kinds of bees. First there is the queen — one to each hive. She has a longer body and shorter wings than the others. She does not leave the Fig. 57. — Drone. Fig 58.— Worker. Fig. 59. — Queen. hive. She lives four years, and goes on lapng eggs the whole time, putting one in each cell. The drone is the male bee. It has no sting and does not work. Hence a lazy person is called a drone. There is oniy IS4 Longmans' Object Lessons one drone to about a thousand workers. In the autumn all the drones are killed. Most of the bees in a hive are workers. They build the cells, gather honey, and tend the young. Structure. — Compare with the structure of the butterfly. The bee may be divided into the same three parts — head, chest, and abdomen. To the chest are similarly joined six legs and four wings. Tongue. — Long, edged with hairs like a brush. With it the worker licks the juice out of flowers. This juice is stored up in a little bag till the worker returns to the hive, when it is squeezed out into a cell, the mouth of which is then stopped with wax. Legs. — On each hind leg is a little basket made of stiff hairs. In this is stored the yellow or white dust found on flowers (the pollen) . This is mixed with honey to feed the young bees. Sting. — The sting is in the hind part of the body, in which also is a poison-bag. It is the poison that causes the part stung to swell and be painful. ' Can you mention other insects with real stings ? ' The young. — As soon as a number of cells are made the queen begins to lay eggs in them. In a few days these change into little white grubs. They have no legs and cannot feed themselves, so a number of workers stay in the hive to act as nurses. After about a week the grubs begin to spin a silken covering for themselves, and when they are about three weeks old they come out perfect bees. Swarming. — The hive then becomes too full, and the queen goes off with a great number of the bees to find a new home. She settles on the branch of a tree, all the rest hanging around her, till the owner comes with a new hive and shakes them into it. Before the swarming a young queen has been hatched, and she becomes the head of the old hive. The Hoiise-Fly '115 5 THE HOUSE-FLY Becapitulate the structure of the butterfly and the bee, and show that the structure of the fly is in many respects similar — head, chest, abdomen ; six legs ;' four wings (with modifica- tion) ; changes. Mouth. — ^The mouth contains the trunk, which is tongue, lips, and teeth all in one. Eyes. — The structure of the eyes is the same as that of the butterflyi Feelers. — Two. It .has been suggested that they may be for hearing and smelling as well as for feeling. Legs. — Six, each with three joints. The feet have claws, hairs, and soft pads. Illustrate the action of a boy's sucker. It is believed that the pads on the fly's feet act in "the- same way, aiid that this is why flies can walk up the window and on the ceiling. Wings. — 'How many ■ wings has the butterfly ? ' 'And the bee ? ' All true insects have four wings. Show a fly, and let the children try to find the four. They will probably be able to find only two ; but if they look very carefully behind those they will see two very small ones. These are called 'bal- ancers ' or ' poisers,' and if even one of them is injured the insect cannot fly, but can only flutter about on the ground. Development. — The fly lays eggs. The warmth of the air hatches these, and out of them come little grubs. Unlike the grub of the butterfly, these have no legs ; but they have a num- ber of sharp bristles set round each of the rings of the body, and by means of these the little creatures can wriggle back- wards and forwards. Refer to bluebottle grub, which the children may Jiave seen in meat. The grubs eat greedily, and in a fewd^ys grqw to their full siz^. . Then tlie skin hardens into a case, and the griib seems dead. Aftef atime the covering (of the 'pupa') bursts, and a fly comes out. 156 Longmans' Object Lessons THE ANT An 'ant-hill.' — Find out the children who have seen an ' ant-hill,' and ask them what they noticed. Bring out by questions that ants, like bees, live together in large numbers ; that their home is not in a hive, but underground ; and that when seen underground they have no wings, though they are true insects. Kinds. — 'How many kinds of bees are there ? ' There are the same three kinds of ants — the males, the females (or queens), and the workers ; but a hive has only one female, while an ant-hill may have several. Wings. — All the ants the children saw in the ant-hill were wingless, and the workers are always wingless ; but in the au- tumn males and females have four wings, and leave the nest in thousands. They choose their mates in the air, after which the males soon die. Such of the queens as escape the birds snap off their wings and start new homes. Development. — The females lay eggs, out of which come little grubs like those of the bee. The largest become females and the smallest workers. They are all quite helpless, and have to be tended by some of the workers. When the grub is about to become an ant it spins a cocoon like that of the silk- worm, only much smaller. Show if possible. Doubtless the children who saw the inside of a nest noticed some of the ants running about with these cocoons, and may have been told (erroneously) that they were eggs. These cocoons must not be too hot or too cold. When the day is warm they are taken to the lower galleries of the nest [' Whyl '], and when the day is cold they are taken up to get what heat they can from the sun. Food. — It is a mistake to suppose that ants store up grain for the winter. They sleep through the cold months just as bees do, and they could not eat grain if they had it. The Spider IS7 Habits. — Give a brief account of some of tlie most interest- ing habits of ants — their wars, their ' slaves,' their ' milking ' of aphides, &c.^ THE SPIDER [Place side by side large pictures of the spider and of some true insect, such as the bee. It would be well also to have specimens of the two creatures.] The spider is not an insect. — By comparing the specimens and the pictures bring out that the spider differs from the bee (or other insect) in the following ways : — (i) The bee has six legs, the spider eight. (2) The body of the bee is divided into three parts— head, chest, and abdomen — -while the head and chest of the spider make oile part. (3) The bee has four wings, the spider none. There are two other very important differences, which the children cannot be made to see : — ( 1 ) The bee breathes through a vast number of little air- tubes which run to every part of its body, and the spider breathes by means of lungs. (2) The bee comes out of an egg and passes through a number of changes, but the spider is born a spider. For these and other reasons we say that the spider is not an insect. Claws. — Spiders live on insects. Some kinds hunt their prey, and others catch it in webs. All kinds kill it with poison. The upper jaw has one or more pairs of claws with a small hole in each. At the base of the jaw is a little bag containing poison. When the spider catches an insect the pressure of the jaws forces some of the poison into the wound. Compare to 1 The white ant, of whose destructive powers such extraordinary tales are told, is not an ant at all. It belongs to the same order as the dragon-fly (the Neuroptera), whereas the ant belongs to the Hymenopiera. 158 Longmans' Object Lessons the action of the fangs and poison-bag of a snake. The poison of the spider is very powerful, arid in hot countries there are spiders which can kill a bird with a single bite,; and can cause much pain even to a man. Web. — There are many kinds of webs — the house spider, for instance, has a different one from the garden spider. Every web is made of threads coming from the spider's body. Near the tail are from four to eight small lumps called ' spinnerets,' each full of little holes. Inside the body is a large bag filled with a. thick, clear fluid. When the spider wishes to spin a web it squeezes a drop of this fluid through the spinnerets and places it against the object to-which it wants to fasten its 'line. It then removes its body, thus drawing out the fluid into a thread which is at once hardened by the air. The line is really made up of a large number of threads, like our ropes. Describe the construction of a web — say, the garden spider's. The threads are very elastic, and covered with a sticky substance. When a fly comes against the web it is caught there by this sticky substance. The spider rushes from the centre of the web or from its hiding-place, grasps the fly, turns it rapidly round and round with its fore feet, covering it completely with a broad silken band which makes it quite unable to move. Then the spider kills it with a bite, and eitlier eats it at once or leaves it till needed. If a wasp or other large insect is caught, the spider does not venture near till the struggles of the captive have caused it to be securely fixed in the web. TBE SNAIL Shells. — ^Snails live in shells. Show. Procure empty shells, and break one or two to show the internal structure. Question on the use of the shell to the snail. If the shell is entirely removed the snail dies.. The 'foot.' — The flat under part which can be seen when The Snail 159 a snail is out of its shell is the ' foot,' by means of which the creature creeps. (See Fig. 60, a.) The head. — ^Joined to the ' foot ' below, but partly separate above, is the head. ,' Fig. 60. — A, external characters; B, snail dissected: rt, /, ante- rior tentacle; col, collar; jn mouth. Tentacles and eyes. — There are two pairs of feelers. Show the action in a living snail. The hinder and larger pair has eyes at the end. Show the advantage of having eyes at the end of feelers which can point in all directions. Let the children see from living specimen how the snail protects its eyes by ' retracting ' and ' inverting ' them. The tongue. — The tongue of the snail, like that of the other creatures of its class, consists of a long band covered with roughnesses often called teeth. This band acts as a rasp or file. Breathing^. — Just within the lip of the shell is a thickened ridge called the ' collar.' (Fig. 60, a, col^ In this is an open- ing leading to the organ by which the creature breathes. Food. — Ask about the action of snails in a garden, and hence elicit that they live on vegetables. They will, however, eat their own dead. Hibernation. — There is a dearth of food in winter, and hence snails pass the cold months in a state of sleep. They i6o Longmans Object Lessons creep into crevices, or under stones, or under heaps of leaves, which they stick together with their own slime. They draw themselves into their shells and cover the mouth with a kind of door. The snail arranges its ' foot ' so as to fill the opening, pours put slime, mixes it with earth, and then withdraws its 'foot.' The cover soon hardens, and the snail sometimes makes two or three more further in of slime alone. Snails delight in warm, moist weather. They are always active at night when the ground is covered with dew, and in the day-time after rain. In hot countries, where there is no winter, they sleep during the dry season. Eggs. — Snails lay eggs about the size of a pea. These eggs are covered by a skin, and may often be found in gardens just under the surface of the soil. Edible snails. — The whelk and the periwinkle, which are only sea-snails, are eaten, and there is no reason why the land- snail should not be eaten also, as in fact it is in France and Italy. The ancient Romans reckoned snails a great dainty, and fattened them for the table. The feeding made them grow to a great size, and an old writer (Pliny) says that three snails, two lettuces, two eggs, a barley cake, sweet wine, and snow made a good supper for himself and his friend. THE EARTH-WORM Lives. — ^The worm is adapted for living underground (i) By its shape. Show a worm, and make the children note that the head is pointed and that there are no parts stick- ing out from the body. (2) It has no legs. The mole, which also lives underground, has very short legs. (3) It is covered with slime. Let the children feel it. This keeps the earth from sticking to the body. Rings and motion.— The body of the worm is made up of a large number of rings. Around most of the rings are set Wild Mustard i6i eight little bristles. These can be felt as a living worm is pulled backwards through the fingers, and they can readily be seen with a lens. The bristles are curved and pointed. The worm moves by extending its body, seizing any roughness with its bristles, and then contracting. Food. — The worm lives chiefly on vegetable matter, especially decaying leaves. Mouth..— The mouth js an opening under the first ring. The worm drags its food underground, and before swallowing mois- tens it with a kind of slime, which helps to digest it. Senses. — Worms come up chiefly at night, and may then often be found half-way out of their holes. If a light be sud- denly shown they withdraw at once, which proves that though they have no eyes they are sensitive to light. They are also very sensitive to any motion, even the breath of a spectator being enough to make them retreat. They have no ears or nose ; but they must have some sense of smell, as they can find out favorite food and distinguish red from green cabbage. They show fondness for carrot, celery, onion, and horseradish. Uses. — Ask if the children have seen on lawns or in meadows the curiously twisted little heaps of earth known as 'worm- casts.' These are the earth dug out by the worm when bur- rowing, and, though gardeners dislike to see them, they are useful as manure. The passages made by the worm are also useful, as they let in rain and air to the roots of plants. The worm also does good by turning leaves and other vege- table matter into manure, which it places beneath the earth where it is wanted. C : Lessons on Flowers WILD MUSTARD [Provide enough flowers, any one of the mustard family will answer, to let each child have at least two perfect specimens. Let each child also have a slate or a piece of paper divided by three horizontal lines into four equal parts.] 1 62 Longmans Object Lessons Calyx. — ' What is the na}?ie of this flower ? ' ' What is the name of this part? ' [The stem or stalk. J Notice that at the top of the stalk and under the blossom there are some little leaves. These seem to form a little cup for the blossom, and are called the calyx. Each of the little leaves forming the calyx is called a sepal. 'How many sepals has the mustard? ' [Four.J ' What is the color of them ? ' In most flowers th^ sepals are green, but in the mustard they are yellowish. 'Are the sepals joined to one another ? ' Let each child pull off the sepals, lay them on the first division of the slate (or paper), and write underneath them, ' Four sepals make the calyx.' Look at the perfect flower and see how the sepals are placed on the stalk. [One pair above the other.] 'Are the sepals of the same size ? ' Corolla. — We now come to the blossom. Those who study plants call this the corolla (a Latin word meaning a small crown) . Each leaf in the corolla is called a petal (a Greek word meaning a leaf). 'How many petals has the mustard? ' [Four.] 'Are they joined to one another?^ Let children pull them off, lay them on the second division of the slate (or paper), and write underneath, ' Four petals make the corolla.' Look at the perfect flower and see how the petals are arranged. [They form a cross.] Notice the shape of the petals. They look like leaves, each with a long white stalk or claw and a broad, colored blade. Stamens. — You now notice a circle of little white threads with powdery heads. Each of these is called a stamen (the Latin word for thread). Let children pull them off carefully and lay them on the third division of the slate (or paper). ' Were the stamens joined to one another ? ' 'How many are there ? ' [Six.] Write, ' Six stamens.' Notice the length of them. [Four long and two short.] Pistil. — ' What is now left ? ' This thickish green body stand- ing- on the stalk is called the pistil because in many flowers it is shaped like a pestle. Let the children pull off the pistil, lay The Phlox 163 it on the fourth division of the slate (or paper), and write underneath, ' Pistil.' Blackboard sammary. Mustard. Calyx = four sepals. (i) Nearly of the same color as the blossom. (2) Quite separate. (3) All equal. (4) Two above, two below. Corolla = four petals, (i) Quite separate. (2) All equal. (3) Shaped like a leaf with a long stalk. Stamens. (i) Six (four long, two short). (2) Quite separate. jPtsiil. [This lesson should be thoroughly reviewed till the children are quite familiar with both the names and the things intro- duced.] TI/£ PHLOX [Let each child have blossoms of some species of phlox, and a slate or paper. Before beginning the last part of the lesson give to each child a flower of one of the mustard family.] Calyx.— 'Co/i^r.?' [Green.] 'Number of points ?' [Five.] 'How many sepals, then?'' 'Are they separate or joined?' [Joined.] ^ox^iiSst..—' Number of petals?' [Five.] 'Equal?' 'Shape?' 'Try to separate one petal from the rest.' [They are united.] The lower parts form a tube. 'Shape of corolla ? ' [Salver- shaped.] Stamens. — 'Take up a corolla from the tipper part of the slate {or paper).' 'Tear it so as to lay open the tube! 'What 164 Longmans' Object Lessons do you see in the tube ? ' [Little yellow heads.J ' IV/iat are these V [Stamens.] 'Count them.' [Five.] 'What do you notice about the length of them ? ' [They are very unequal.] 'Now tear open a corolla from the lower part of the slate {or paper) .' ' Where are the stamens ? ' [In the lower part of the tube.] ' Count them.' [Five.] ''Where are the stamens fixed in the flowers ? ' [On the tube of the corolla.] 'Are they equal in length ? ' [No.] Pistil. — Cut or tear open a calyx from the upper division. ' What do you see on the stalk ? ' [The pistil.] Point out resemblance in shape to a pestle, mentioned in the last lesson. Now cut or tear open a calyx from the lower division. Show the pistil. ' What is the difference between the pistils of the two flowers cut open ? ' [The pistil in the upper division is short, and in the lower division long.] 'Into how 7ttany parts may each pistil be divided ? ' [Three.] (i) The little lump at the top of the flower stalk is called the oiiary. (2) The thread running up from the ovary is called the style. (3) The little lump at the top of the style is called the stigma. Comparison with mustard. — Work out the comparison, which will give the following blackboard summary : — ,. Mustard Phlox Calyx . . Yellowish Green Four sepals Five Separate United Corolla . . Four petals Five Separate United Slamsns Six Five On stalk On petals Long threads Short and long threads Pistil . . The same in every flower The Buttercup 165 THE BUTTERCUP [Provide flowers as in tlie preceding lessons. Also, as in tlie lesson on the mustard, let children have slates or paper divided horizontally into four equal parts. The number of sepals, &c. varies very much in the different and even in the same species.] Calyx. — ' What is the name of this flower ? ' ' Show the calyx.' 'How many sepals ? ' [Five.J ' Color ? ' [Yellowish-green.J [Under the name Bitttercup are included at least three differ- ent flowers, all common. . It matters little which kind is taken, but note that the sepals are spreading or sharply curved back according to the kind of flower taken.] Make the chil- dren observe that the sepals are equal and quite separate (' free '). Let children pluck off sepals and place them on the highest division of their slates (or papers), writing, ' Calyx = five sepals.' Corolla. — 'Color?' 'How many petals V [Five.J Have the petals plucked off and placed on second division of slates (or papers) . ' Five petals = corolla.' Make children observe that the petals are equal and quite separate (' free '). Petal of mustard was like a leaf with a long stalk or claw. Petal of buttercup is almost, but not quite, without stalk. Stamens. — Have them plucked off and placed on the third division of slates (or papers). Ask children to count them. Answers will probably vary ; no answer will be under twenty. In such cases the number of stamens is said to be ' indefinite.' Stamen can be easily divided into two parts — (i) A thread-like stalk, called a. filament (from a Latin word meaning a thin thread). (2) A yellow head, called the anther. From the anthers comes a yellow dust, called /(?//(?«. Pistil.— Each of the little green points now left is the stigma of one part of the pistil of the buttercup. Each part is called a carpel. Place them on the fourth division of the slate (or paper). Count them. [Indefinite.] Write, ' Carpels (indefinite) = pistil.' 1 66 Longmans' Object Lessons 'Into how many parts did we divide the pistil of the phlox ? ' [Three — stigma, style, ovary.] The ovary and style may be seen in each carpel of the buttercup. Inside the ovary is a little body which becomes the seed. Blackboard summary. — Recapitulate the lessons on the mustard and the phlox so as to bring out the table given at the end of the second. Add another column with details of the buttercup. CATMINT OR CATNIP^ Mints. — There are many kinds of mints growing wild in all parts of the country. Some are native ; others came originally from Europe, as the catmint. This lesson may be given on any one which can be procured, although those having the largest flowers are preferable. Calyx. — Green ; easily detached ; five sepals, united ; not all of the same size. Corolla. — Note the shape. The petals of the preceding flowers were of the same size ; these are unequal. The corolla is supposed to look something like a mouth with two lips \bi- ladiate']. The upper one, which bends over, has two divisions, the lower one three. There are therefore five petals (united). Stamens. — The little hollow box which stands at the summit of a stamen is the anther, and contains the pollen. The anthers of the catnip are purple. By counting them it will be seen that there are four stamens. The two lower ones are longer than the other two. The stamens, as in the phlox, spring from the corolla tube, as will be seen if it is cut open. •» Pistil. — Long, white, forked at the top. Insects. — It is necessary that the pollen of one flower should be carried to another. This is a task which insects often un- consciously perform in their search after honey. The peculiar shape of the catnip facilitates the deposit in one flower of the 1 In this and the following lessons on ilowers the same method should be followed as in the preceding. Only the facts are given here. The Daffodil 167 pollen caught on the body during a visit to another. The stiff hairs placed inside the corolla tube are supposed to be for the purpose of keeping small insects away from the honey. THE TULIP [Illustrate with ' single,' not ' double ' flowers .] Calyx and corolla. — The flower seems to have no calyx, and the corolla to be made up of six equal petals not united. These are arranged in two circles of three, the leaves of the outer circle being placed opposite the openings between those of the inner circle. When the calyx and the corolla are thus alike they are called the perianth. (Gr. Trepi — -peri — ' around,' and a.vQo'i — anthos — ' a flower.') Stamens. — Six, conspicuous, springing from the end of the stalk below the pistil. Pistil. — Also conspicuous ; has three lobes or divisions. Leaves. — Parallel venation. (Seep. 122.) THE DAFFODIL [Cultivated daffodils, like many other cultivated flowers, are generally ' double.' For the purjjoses of this lesson procure any ' single ' narcissus.] Name. — The connection between the word daffodil and the word asphodel may be passed over ; but as the children have probably heard the flower called the March lily and the Lent lily the teacher should explain that it receives these names be- cause it has some likeness to the lily and blooms in March and April (Lent). Feriauth.. — As in the tulip, there is no separation of the flower leaves into calyx and corolla, all being of the same color and nearly on the same level. Outside whorl (or circle), three ; inside whorl, three, of the same size, and all united. Corona. — In the middle part of the flower is a large deep tube to which the leaves of the perianth adhere. This is called 1 68 Longmans^ Object Lessons the corona (Lat. ' a crown ') from its shape and position. Impress upon the children that it is not the corolla. Stamens. — ^Three above and three below ; all on the tube of the perianth. Pistil. — Style long ; stigma triangular ; ovary three cells (as may be seen if a transverse section is made) ; therefore three carpels. Leaves. — Parallel venation. THE GARDEN PEA [The meadow pea and the sweet pea will serve equally well for illustration.] Calyx. — Green. The flower therefore differs from the tulip and the daffodil in having no perianth. The sepals are united, but the teeth show that they are five in number. Corolla. — Butterfly-shaped, like that of the bean. The petals are unequal. The largest (at the back) is called the standard. The two situated below it, one on each side, are the wings. It might, at first sight, appear that there is but one more, enclosing the stamens ; but closer examination will show that there are two, slightly coherent along their lower edges. These two are called the keel. Stamens. — If a section be made through the middle of the flower from below upwards, the stamens will be seen, owing to a slight adhesion contracted, with the bottom of the calyx, to spring from its lower part. There are ten stamens, nine united by their filaments (or stalks) into a bundle, and the upper one distinct. Pistil. — The pistil is free from the calyx, and consists of a single carpel. Ripened it is the pod, to which the calyx adheres. Leaves.^ — Compound, with stipules (large in the garden pea, but much smaller in the meadow and sweet pea) . The upper ends of the leaf-stalk are changed into tendrils. The stem is too weak to stand upright of itself, and the tendrils help the The Daisy i6g plant to find support by climbing. The leaf is in constant motion, going round and round by ' bowing ' in all directions, so as to enable the tendril to reach any neighboring object. THE DAISY [The parts of a daisy (even of a ' dog ' daisy) are too small to be seen properly without a magnifying glass, and in most cases provid- ing each pupil with a glass is out of the question. The teacher should therefore have a good one, and draw clearly on the black- board what he sees.] Bays and disc. — The white leaves outside are called rays, and the yellow ones inside form the disc. Florets. — If a few of the white leaves and a few of the little yellow bodies be examined under the glass it will be seen that they are hollow, and that each one is, in fact, a little flower. The daisy, therefore, is not a simple flower like those hitherto taken, but it is made up of many little flowers, each called a floret. Compound. — Flowers which (like the daisy, the dandelion, the marigold, the thistle, &c.) are made up of florets are said to be compound or composite. Disc florets. — When one of the disc florets is examined under the glass, the corolla is seen to have five points — in other words, it has five petals which are united. The calyx is difficult to distinguish, but it is present. There are five stamens inserted on the corolla and united by the anthers. Ray florets. — The ray florets have strap-shaped corollas made up of five petals united. The calyx here also is diffi- cult to distinguish. There are no stamens. Involucre. — Around the base of the ray florets is a circle of green leaves looking like a calyx, but a compound flower has no calyx. This whorl is called an involucre, and each leaf is called a bract. Common receptacle. — With a sharp knife make a cut down- wards through the middle of a daisy. The white and yellow florets will be seen to stand (without stalks) upon a rounded 1 70 Longmans' Object Lessons enlargement of the flower stalk. In simple flowers this is called the receptitcle, and in compound flowers the common receptacle. THE DANDELION Dandelion and daisy. — Like the daisy, the dandelion is a compound (or composite) flower ; but there is one obvious difference — in the dandelion the florets are all yellow, whereas in the daisy some are white and some yellow. Pappus. — Take one of the outside florets. In the lower part will be seen a little oval body, the ovary. On the top is a ring of hairs (Fig. 134). This takes the place of the calyx, and afterwards forms the down which carries the ripe seed through the air. Corolla. — Rises from the top of the ovary from within the hairs. It begins as a tube, but spreads out as a strap ending in five points. Hence we say that it has five petals, united. Stamens. — Five. The filaments spring separately from the tube of the corolla, but, as in the case of the daisy, the anthers unite. Down. — When the seeds of the dandelion are ripe the bracts turn backward. Each corolla falls away, and the narrow part between the ovary and the pappus grows straight up, bearing on it the pappus, which gradually spreads out horizontally as down. When the seed is ripe, it is with the least breeze car- ried into the air by the down. COMPARISON [(i) The flowers examined in the present course should now be compared, not by recollection, but by fresh observation. As many of them as are in bloom should be produced ; for the rest there should be drawings and pressed specimens. (2) The chief facts about a flower may be shown by means of a schedule such as follows. In the column headed 'Cohesion' the facts with regard to the union or freedom of the parts of any whorl are stated, and in the cokimn headed ' Adhesion ' the facts with regard to the union of whorls.] Comparison. 171 Flower Organ No. Cohesion Adhesion Mustard . . Calyx Sepals . 4 Free (equal) . Not attached to Corolla pistil. Petals . 4 Free. Stamens . 6 Free .... Below the pistil. Pistil Carpels . 2 United . . . Not attached to calyx. Phlox . . . Calyx Sepals . S Coherent Not attached to Corolla pistil. Petals . 5 Coherent. Stamens . S Free .... Spring from co- rolla tube. Pistil Carpels . 5 United . . . Not attached to calyx. BU'l-lKRCUP . Calyx Sepals . S Free .... Not attached to pistil. Corolla Petals . S Free (equal). Stamens . Indef- inite Free .... Below the pistil. Pistil Carpels . Indef- inite Separate Not attached to calyx. Catnip . . . Calyx Sepals . S Coherent . . Not attached to pistil. Corolla Petals . S Coherent (un- equal) Two long, two short Below the pistil. Stamens . 4 From the petals. Pistil Carpels . 2 United . . . Not attached to calyx. TULIP . . . Perianth Applied to peri- Not attached to Leaves . 6 anth, consist- ing of free leaves pistil. Stamens . 6 Free .... Below the pistil. Pistil Carpels . 3 United . . . Not attached to calyx. 172 Longmans Object Lessotis Flower Organ No. Cohesion Adhf^ion Daffodil . . Perianth Leaves . 6 Applied to peri- anth, consist- ing of united leaves Stands in place of calyx. Stamens . 6 Free .... Attached around ovary. Pistil Carpels . 3 United . . . Adherent to ovary. Pea ... . Calyx Sepals . 5 United . . . Not united to pistil. Corolla Petals . S Free .... Attached around ovary. Stamens . 10 Arranged in two sets Attached around ovary. Pistil Carpels . I One carpel . . Not united to calyx. DAISY, Dan- Calyx delion Sepals . Corolla . S United . . . Not attached to pistil. Petals . 5 United . . . Attached above pistil. Stamens . 5 United by an- thers Attached to pet- als. Pistil Carpels . 2 United . . . Not attached to calyx. FOURTH YEAR A : Lessons on Elementary Physics SOLIDS, LIQUIDS, AND GASES Solids and liquids. — Place on a table in front of the class a number of the solids and liquids most readily available. Get the children to divide the solids from the liquids, and to name other solids and liquids. Cohesion. — Ask the children to push their fingers first through the solids, then through the liquids. ' What is the difference ? ' The particles that go to make up a solid stick so close together that it is hard to separate them ; but the particles of a liquid can be easily separated. The force which holds the particles together is called cohesion. Elicit the statement that cohesion is strong in solids and weak in liquids. Gas. — Turn on the tap without lighting the gas. In a very short time the furthest children will be able to smell the gas. This shows that the gas has spread throughout the room. All gases spread in the same way. They have no cohesion. Recapitulation. — Compare the properties of solids, liquids, and gases. A. (i) A solid retains its size and its shape. (2) A hquid retains its size, but will change its shape. (3) A gas will change both size and shape. B. (i) Cohesion is strong in solids. (2) It is weak in liquids. (3) There is no cohesion in gases. Change of state. — If possible, show a piece of ice, and elicit that it is water in a solid form. Warm it, and it takes a liquid form. Warm still more, and it becomes a gas (steam) . 173 174 Longmans' Object Lessons Few substances are commonly found in the three states, but many solids are easily changed into liquids \^Name some.''\, and liquids into gases \_'Name some.''\ . EFFECTS OF HEAT [Two lessons.] Change of state. — Refer to the closing part of last lesson, where it was shown that heat may change a solid into a liquid and a liquid into a gas. Expansion. — But it must not be supposed that heat has no effect till a change of state has taken place. Solids, liquids, and gases expand when heated. The expansion of liquids an4 gases may be easily demonstrated, but the smaller expansion of solids is generally shown by means of delicate apparatus. Illustrations of the expansion of solids. — (i) A metal rod (a. Fig. 6i) is fixed at one end by a screw, B, while the other Fig. 6i. end presses against the short arm, c, of an index, d, which moves on a scale. Alcohol is poured into the trough under the rod and lighted. As the rod is heated it expands, and Effects of Heat 175 moves the index. If rods of different metal be used, the dif- ferent degrees of expansion will be seen. (2) The apparatus in Fig. 62 consists of a brass ball, a, which, at ordinary temperatures, passes freely through the ring, m, but which, when heated, will not pass through. (3) Where no special apparatus is available, the expansion of solids, though too small for measurement, may be made visible in its effects. 'A bar or rod of iron about 18 inches long rests upon two blocks of hard wood. One end of the bar is held firmly by a heavy weight. The other end rests upon a sewing-needle. A light straw is fastened at right angles to the needle with sealing-wax, and a divided semicircle is fixed be- hind the straw. [This may be omitted.] If the rod moves to the right or left, the needle will roll and the pointer will move to the right or left, A very slight movement of the bar will cause a considerable movement of the index. Heat the bar with a spirit-lamp. The temperature rises, and the pointer Fio. 62. Fig. 63. informs us that the bar is expanding. On cooling, the pointer moves to the left, showing that the bar is contracting.' — Wright, Physics, p. 3. (4) Let a knitting-needle stand obliquely with its lower end resting against a weight and its upper end against a thin board 176 Longmans' Object Lessons placed on end. The board should be so placed that the smallest motion of the needle will cause it to fall. Warm the needle, and the expansion of the metal will cause the board to fall. Practical applications. — (i) The tire of a wheel is, when cold, slightly smaller in circumference than the wheel itself. When heated the tire expands, and is placed on the wheel. It contracts as it cools, and remains firmly fixed. (2) The pipes of the hot-water apparatus for warming a building expand as the water passes through thepn. To allow for the expansion the pipes are made to slide one within another. (See Fig. 64.) Fig. 64. (3) The summer sun expands the rails of tramways and railways. If no room were allowed for expansion the rails would curve upwards. Spaces (a and b. Fig. 65) are accord- ingly left at the ends. (4) A thick glass or bottle often cracks when hot water is poured into it. The glass being thick, the inside is expanded before the outside. Fig. 65. (s) A Stopper fixed in the neck of a bottle may often be got out by plunging in hot water, the neck expanding more than the stopper. The same effect is produced by friction on the neck. Cohesion. — The force of cohesion is diminished when solids are heated. Suspend a weight from the end of a piece of wire ; heat the wire, and it breaks. Effects of Heat 177 When a blacksmith wants to cut a piece of iron he first heats it to diminish the cohesion. Expansion of liquids. — Fill a small flask with water colored with a little red or blue ink. In the neck insert a cork having a glass tube passing through it. Warm the flask, and the water will rise in the tube. Thermometer. — Heat is measured by the contraction and expansion of liquids. Have three vessels, the first containing cold, the second tepid, and the third rather hot water. Let one of the children dip his finger into each and arrange the three in order of heat. Now let him first place one hand in the hot and one in the cold water, and then both hands at once in the tepid, which will seem warm to one hand and cold to the other. This shows that we can generally, but not always. tell by our feelings whether a thing is hot or cold, but that we cannot tell how hot or cold. This is done by means of a thermometer. Show one. Show that the liquid expands when heated. There are two fixed points on a thermometer, one showing where the liquid stands in ice (' freezing-point'), and the other where it stands in steam (' boiling-point '). In cheap thermometers this second point is not givea 178 Longmans' Object Lessons Mercury is the liquid commonly used. It is open to the dis- advantage of freezing in great cold. Colored alcohol (which is often used) has an opposite disadvantage : it becomes vapor in great heat. Water. — Water contracts with cold till it is nearly freezing (39-2° Fahr.), and then expands. Elicit that this is why ice floats and pipes burst. Gases. — Gases also expand when heated. The flask (Fig. 66) contains only air, and the test-tube is at' first full of water. The flask is heated and the air expands, driving the water out of the test-tube. As the air cools it contracts, and water rises again in the tube. PRESSURE OF LIQUIDS Downward. — Pour some water into a tumbler. 'What is now pressing on the bottom of the tumbler ? ' [The pressure of the atmosphere may be ignored.] ' What is the amount of the pressure ? ' [It equals the weight of the water.] Pour in more water. ' What, change has taken place in the pressure ?' Point to different depths, and by asking what the pressure at each point is, elicit that it equals the weight of the water at that point, and therefore varies with the depth. Sideways. — Liquids, besides pressing on the bottom of a vessel, press on the sides, and the pres- sure on the sides varies, like the pres- sure on the bottom, with the depth. To illustrate this, provide a deep tin with three or four holes at different depths on one side. Close these holes with the fingers and fill the tin with water. Remove the fingers, and a jet ^^°- ^T- of water will spout out of each hole. Make the children observe that the lower the hole the longer the jet, and elicit the reason. If the children have seen a reservoir, canal, or embankment, Pressure of Li quids 179 ask what they have noticed about the sides, and why the sides are made thicker as they go down. Upward. — Liquids also press upward. It is the upward pressure which makes things float, or causes water to enter a hole in a ship's side. As the upward pressure is equal to the down- ward, it is greatest at the greatest depth. Invert a tumbler in some water. Make the children notice that as the tumbler is pressed down some water enters it. ' What was there in the tumbler at first? ' ' What must have happened to the air?' ' What pressed it closer ? ' 'How must the water have been press- ^^^ j„ ing?' Take a cylindrical glass open at both ends (such as a lamp- glass), with a disc of glass, mica, or card fitting closely to one end. Hold the disc un- der the cylinder with the hand or by means of a piece of string, and push the cylinder into the wa- ter. The upward pres- sure of the water will keep the disc in its place. Pour some water into the cylinder till the downward pressure equals the upward, and the disc will fall off. Transmission of pres- sure. — Push something along the table by means of a rod or ruler. ' What made this move ? ' Children will probably say that the teacher moved Fig. 6g. i8o Longmans Object Lessons it. He will, however, point out that he did not touch it. Hence elicit that the pressure passed through the rod or ruler. Make the class observe that solids transmit pressure in one direction only. Emphasize this fact. Take a hollow indiarubber ball and make in it a number of pin-holes. Fill it with water, and, holding a finger over large hole, press. Water will come out through each of the pin- holes. Make the children note that, though you pressed in only one direction, the pressure is transmitted in all directions. Multiplication of pres- sure. — Liquids not only transmit pressure in all di- rections, but the pressure transmitted is proportioned to the extent of surface. If the surface at p (Fig. 70) is 20 times that at/, i lb. at/ will balance 20 lbs. at p. Give other questions of the same kind. This is the principle of the hydraulic press. Fig. 70. PRESSURE OF THE AIR [Two lessons.] Amount of pressure.— The air is known to reach many miles above the earth. Above every square inch on the face of the earth there is, therefore, a column of air weighing about 15 lbs. Show a piece of paper, card, or board i foot square. Hold it horizontally. The air above it weighs nearly a ton. ' Why is the weight not felt ? ' Review what was said about the pressure of liquids, especially that upward pressure equals downward. That is true also of the pressure of the air. Repeat question, ' Wliy is the weight of the air on the paper not felt ? ' When pressure is felt. — The pressure of the air is felt when exerted on one side only. Pressure of the Air i8i If an air-pump is available, perform the following experiment. On one end of a stout glass cylinder, about 5 inches high and open at both ends, a piece of rub- ber cloth is tied quite air-tight. The other end, ground and well greased, is pressed on the plate of the air- pump. At first the weight of the air above the bladder is coun- terbalanced by the expansive force of the air inside the cylinder, but when the internal air is pumped out Fig. 71. I 1 ■ I ^* v^v'T'^ - A. the bladder is depressed, and finally bursts with a loud report. Where Magdeburg hemispheres (Fig. 72) are available, pump l82 Longmans' Object Lessons Fig. 74. out the air, and then let two children try to pull them apart. As the air presses on the outside only, they will not succeed. Many simple experiments can be per- formed without an air-pump. Care should be taken that the point illustrated is made clear. ( I ) A sucker. A piece of leather a few inches square. The string should fit very tightly into the hole, and the knot should be very flat. Damp the sucker, and press it well against the floor or any other flat surface. (2) Fill a tumbler with water and cover it with a piece of paper, taking care that the paper touches every part of the rim. Invert the tumbler, keeping the pa- per in position with the hand. Take away the hand, and the water will remain in the tumbler, being kept in position by the up- ward pressure of the air. The object of the paper is to preserve a flat surface of water. Without it the water would divide and allow the air to enter. (3) 'Fill the tumbler with water and cover it as before. Invert with the mouth under water. Remove the paper. Question out why the water remains in the tumbler. Emphasize the fact that the pressure of the air on the sur- face of the water in the dish is transmitted to the water in the tumbler. (4) The wine-tester. This is a tin tube ter- minating in a small cone, the end of which (0, Fig. 75 ), is open. There is an opening at the top. The tube is immersed in the liquid to be tested, and filled. The upper end is closed with the thumb, and the tube withdrawn. The up- ward pressure of the air at keeps the liquid 'Why?' Fig. 75. Sililllll !!i;!!il:l iili'lillrll Fig. 76. in. When the thumb is raised the liquid runs out. Pressure of the Air 183 (5) Another illustration of the same principle. A number of small holes are made in the bottom of a tin can (b, Fig. 76), and a hole is also made in the cork (a) . The can is filled, and as long as the thumb is kept on the mouth the water remains, but when the thumb is removed the water runs out at the bottom. Fig. 77. Fig. 78. Suck out the air. (6) Place one end of a tube in water, and the water rises in the tube. ' Why ? ' (7) The same effect is produced when the nozzle of a syringe is placed in the water and the air is withdrawn by means of the piston. [Show.] Barometer. — Take a glass tube about a yard long and a quarter of an inch in internal diameter. Close one end by 184 Longmans' Object Lessons holding it in the flame of a Bunsen burner. [Proper barom- eter-tubes may be bought ready.] Fill the tube with mer- cury; then place the thumb on the mouth (c, Fig. 77) and invert the tube (a b) in a small mercury trough. The mer- cury in the tube sinks till the column is about 30 inches high, and then remains stationary. Elicit that the mercury is kept in the tube by the pressure of the air on the surface of the mercury in the trough. Elicit (i) that there is a vacuum at the top of the tube ; (2) that pressure is therefore exerted in only one direction ; (3) that the height of the column varies with the weight of the air. This is the principle of the barometer. Wheel barometer. — Common barometers generally consist of a bent tube, with a long arm closed and a short arm opened at the end. There is a vacuum at the top of the long arm, and the mercury is kept up by the pressure of the air on the sur- face in the short arm. The height of the column may be shown by a needle on a dial. The float (Fig. 78, a) rises and falls with the mercury. A string attached to the float passes over a pulley, and has at the other end a weight (b') somewhat lighter than the float. The needle (it) is fixed to the pulley, and moves round as the mercury rises or falls. What a barometer tells. — A barometer really tells not what the weather will be, but what the weight of the air is. At the same time there is some connection between the two things, because when the pressure is high we are more likely to have fine weather than when the pressure is low. A sudden fall of the mercury column in the barometer indi- cates the approach of a storm. The scales on common barometers are altogether misleading. THE PUMP [This lesson will be of little use unless illustrated by a model. The barrel must be made of glass, so that the action of the valves may be seen. These are not bound to be of the same form as in an The Pump i8s ordinary pump, and the piston may work as in a syringe, without a lever handle.] The syringe. — Introduce the syringe once more. Push the piston to the bottom of the barrel, and place the nozzle in the water. Let the children think of the surface of the water as divided "into two parts — the part inside the syringe, and the part outside — and make perfectly clear that the air is pressing on both. Fig. 79. Pull up the piston. ' What has become of the little air that was between the piston and the water?' Make clear that this would have expanded so as to fill the whole barrel, if the water had not risen, and in that condition it could have exerted little pressure on the water inside the syringe. The external air presses on the water outside the syringe, and the pressure is transmitted, causing the water to rise in the barrel. The principal of the pump is the same as that of the syringe. Suction or lifting pump. — The common suction or lifting 1 86 Longmans' Object Lessons pump consists of a cast-iron (or wooden) cylinder called the barrel, at the bottom of which is a pipe of smaller diameter dipping into the well. At the top of this pipe is fixed a valve which opens upward Fig. 8i. like a trap-door. Make perfectly clear that the valve opens upward only. The piston moves up and down the barrel. It consists of a disc of metal or leather coated with tow or leather. ' Why ? ' The Pump 187 In the piston is a small hole closed at the top with a valve which also opens upward only. The piston-rod is worked by a lever, which is the handle. Action. — ^The action of the pump will be seen in the model. Record the observations by making drawings on the blackboard Fig. 82. Fig. 83. showing the position of the valves and of the water at different stages. (i) When the pump is idle the barrel and the pipe are full of air under ordinary pressure, which counterbalances the pressure of the air on the surface of the well outside the pump. Hence the level of the water inside and outside is the same. (2) When the piston rises (Fig. 82) the valve c is pressed down by its own weight and the weight of the air above it. Hence a partial vacuum would be created below the piston ; but for the fact that the air which fills the pipe b being elastic opens the valve a, and passes into the barrel. The pressure of 1 88 Longmans Object Lessons the air inside the pipe being now less than the pressure on the surface d of the well outside, water rises in the pipe and through the valve a into the barrel (Fig. 82). (3) If, now, the piston sinks (Fig. 83) the valve a closes [' Why ? '], the air in the barrel is compressed, raises the valve c, and escapes into the top of the barrel. With the next ascending stroke of the piston the valve c falls [_'lVhy?'~\, the valve a opens \JWhy?''\, and the water being thus raised in the pipe passes above the valve a, and completely fills the barrel (Fig- 83). (4) From this time, when the piston redescends and the valve a closes, the pressure exerted on the water raises the valve c, and the water passes above the piston (Fig. 84). The valve c closes when the piston ascends, and the water which has passed above the piston being raised with it, flows out of the spout. Height. — Refer to the part of the last lesson which dealt with the barometer, and see that the children clearly under- stand that the weight of a column of mercury equals the weight of a column of air of the same diameter. Then make clear that this principle applies to the column of water in a pump. But water is much lighter than mercury, and the pressure of the air is sufficient to hold up a column of water about 34 feet high. But in practice the vacuum produced in the barrel is never perfect, and so a pump will not raise water quite so high. Force-pump. — If it is necessary to raise water higher, a force- pump is used. In this the piston p has no valve, and there is no lifting-pipe, the barrel being immersed in the water to be raised. There are two valves in the barrel ; one, a, in the Fig. 84. Eqidlihrium of Liquids 189 bottom, opens upward ; the other, c, is placed at the mouth of a long tube h in the side of the pump. When the piston rises (Fig. 85), the atmospheric pressure acts on c and closes it, while the water in which the pump is immersed being forced by its own weight and that of the atmos- phere, raises the valve a and passes into the barrel, which it fills. Fig. 85. When the piston descends, the valve a (Fig. 86) closes by its own weight and the pressure of the water above it, while the valve c opens and allows the water to pass into the pipe. The height to which it will rise in the pipe depends upon the force with which the piston descends. EQUILIBRIUM OF LIQUIDS Surface of liquids. — Fix a string horizontally. See that the children know the meaning of horizontal. Hold a water-bottle or other glass vessel containing water so that the surface of the 1 90 Longmans' Object Lessons water shall ba on a level with the string. Make the children note that the surface is horizontal, and that it remains so how- ever the vessel may be tilted. Level in communicating vessels. — When vessels containing the same liquid communicate with one another the level of the liquid is the same in each. This is often illustrated by a special apparatus, like that Fig. 87. shown in Fig. 87, which makes clear the fact that uniformity of level is independent of the size or shape of the vessels. If special apparatus is not available and a substitute cannot be constructed, illustrate by means of a tea-pot. The level is the same in the pot and in the spout whatever may be the position in which the pot is held. Applications. — (i) The water-level.-^lxs. the construction of railways, canals, and roads it is often necessary to find the dif- ference in level between two place". The simplest apparatus employed is the water-level, which consists of a metal tube bent at each end, with glass tubes fitting into the bent ends. When the liquid is at rest the level in both tubes is the same. Fig. 88 shows how the apparatus is used. Equilibrium of Liquids 19' (2) Tlie engine-gauge. — This enables an engineer to see how much water is in liis engine. The gauge consists of a glass Fig. 88. tube placed outside the engine, and communicating at each end with an opening in its side. [The stop-cocks (e and f, Fig. 89) are used to break the communication when a new gauge has to be fitted.] The water in the gauge stands at the same height as that in the engine. ' What presses upon the sur- face of the water, both in the gauge and in the boiler ? ' ' Why is it necessary that the upper end of this gauge should commu- nicate with the boiler ? ' ( 3 ) Fountains. — Get two or three yards of indiarubber tubing. Fix one end over the spout of a can and in the other place a nozzle (which may easily be made out of a httle piece of glass tubing) . Fill the can with water, and let some run into the indiarubber tube, the nozzle pointing up- ward. If the can is lower than the nozzle, no effect is ap- parent ; if the can is higher, we have a jet of water from the nozzle. Fig. 89. 192 Longmans Object Lessons Apply this to actual fountains. The can is the reservoir, which is always much higher than the top of the jet, for the Fig. 90. friction of the pipe and the resistance of the air have to be overcome. (4), Waterworks. — Apply the same illustration to water- works, letting the can stand for a reservoir or water-tower and Fig. 91. the nozzle for a tap. If a reservoir cannot be constructed on ground higher than any point to which water has to be supplied, a tower is built or a great pipe is made higher, and the water is first forced to the top and then allowed to run hence. Capillary Attraction 193 CAPILLARY ATTRACTION [The way in which capillary force acts depends upon whether the liquid (like water) does or (like mercury) does not moisten the tube. In this lesson only liquids that moisten will be dealt with.] Illustration. — Place a little colored water in a saucer or other shallow dish. Immerse in it the lower ends of several glass tubes of very narrow bore (' capillary tubes ') . Make the children note — (i) That the water rises in each tube. (2) That it rises highest in the narrowest. Capillary. — The channels in the little tubes being hair-like are called ' capillary ' (Latin capillaris, hair-like, from capillus, hair). If any substance containing hair-like openings or pores is placed in a liquid, the liquid passes up the openings. The force drawing it up is called ' capillary attraction.' Other illustrations. — Place two rectangular pieces of glass of equal size face to face. Separate the upper edges by means of a narrow strip of thick paper. Immerse the lower edges in the colored water, which will rise between the two pieces of glass. The height to which it will rise will vary with the thickness of the strip of paper. Place in the colored water pieces of bread, sugar, salt, sponge, and other porous substances, and the ends of a Fig. 92. Strip of blotting-paper, and of a piece of cane. The water will rise in each through the openings, which are, in effect, the same as the channels in the capillary tubes. 194 Longmans" Object Lessons Place two wine-glasses on different levels. Into the higher pour some colored water. In this insert one end of a piece of cotton wick. Let the other end dip into the lower glass, and the water will quickly pass into it. Applications. — Perhaps the most common application of capillarity is seen in a kerosene lamp. Amplify. A similar application is seen in a burning candle. (See p. I33-) Plants growing in pots are often watered by water being poured into the saucer. The same principle is applied in hyacinth pots (Fig. 93). MAGNETS Magnetic attraction. — Show that a magnet will attract pieces of iron and steel. Polarity. — Plunge the two ends of a bar magnet into iron filings. [The box or bottle containing the filings should stand on a large sheet of paper, so that the filings will not be spilled ■^iivrt/w Fig. 94. on the table.] The filings will adhere in a tuff to each end of the magnet. Perform the same experiment with iron tacks. These experiments show that the magnetic power resides chiefly at the ends of the magnet. These are called the poles. The experiments also show that the magnetic power is trans- mitted. One steel pen will not attract another, but the first, if held up by the end of a magnet, will in its turn hold up the second. North-seeking and south-seeking. — Balance a bar magnet in a small paper stirrup suspended from a single fine cord Magnets 195 Fig. 95. which does not untwist of itself (such as horse-hair, cat-gut, or carefully woven silk fishing-line). If we do not let the magnet turn round so as to twist the cord it will always come to rest in one particular position. [There should be no draughts, and all iron should be removed from the neighborhood.] The magnet will always be found to point north and south, and the same end will always be found to point in the same direction. The ends are called north-seeking and south-seek- ing. Find the north-seeking ends of two bar magnets, and gum a piece of paper on each. [If preferred, the north-seeking end of a bar magnet may be discovered by laying the magnet on a piece of cork floating in water.] Attraction and repulsion. — Suspend one of the bar magnets. To its north-seeking end bring the north-seeking end of the other. It will be found that the two ends repel one another. Bring the south-seeking ends together, and the same effect will be observed. Now bring the north-seeking end of one up to the south- seeking end of the other, and it will be found that they attract one another. Like poles repel ; unlike poles attract. To make a magnet. — Suppose we want to make a magnet of a steel knitting-needle. Lay the needle on the table and stroke it several times in the same direction with one pole of a bar magnet. Prove that the needle is a magnet by dipping the ends in iron filings. Fig. 96. 196 Longmans' Object Lessons Parts of magnets. — Every part of a magnet is a magnet. Break into several pieces the needle just magnetized, and show that each piece is a magnet. Fig. 97. The mariner's compass. — One of the most important prac- tical applications of magnetism is the mariner's compass, but there will be no time to describe it in this lesson. It should, if desired, form the subject of another lesson. B : General Lessons on Natural History MAMMALS Classification. — Write on the blackboard the names of some of each kind of creature dealt with in the preceding lessons, such as the cat, dog, horse, cow, hen, duck, herring, frog, crocodile, snake, butterfly, bee, spider, snail, earth-worm. Ask the children to separate the creatures that have bones from those that have none, and write the names in two columns. Direct attention to the boned animals, and ask in each case on what they feed their young. Write by themselves the names of all animals that feed their young on milk, such as the cat, dog, horse, and cow. Ask for others of the same kind. All animals that feed their young on milk are called Mammals. Warm-blooded. — Ask what children have felt a cat, a dog, a bird, a fish, and a frog. Emphasize the fact that the mammals and the bird were warm, the fish and the frog cold. Mammals and birds have warm blood, fish and reptiles cold. Air-breathing. — Ask the children with what they breathe. Illustrate the action of the lung^. The oxygen which we take The Whale 197 into the lungs purifies the blood and warms it. All mammals breathe air by means of lungs. Limbs. — ^How many limbs have we ? ' ' What are they ? ' 'How many limbs have monkeys ? ' The four are called hands. 'I/07V many limbs has a dog?' 'What are they? ' Question similarly about other mammals, and thus bring out the fact that most of them are four-footed. Coverings. — Ask questions about the coverings of various mammals, such as the cat, dog, horse, sheep, pig, elephant, camel, bear, and beaver, and thus bring out the fact that nearly all mammals are clothed in hair — which may take the form of wool, as in the sheep ; of bristles, as in the pig ; of fur, as in the beaver ; and of spines, as in the hedgehog. Jaws. — Make the children consider the action of their own jaws, and thus find out that the upper one is fixed and the lower movable. This is the case with other mammals. THE WHALE Not a fish. — Though the whale lives entirely in the water it is not a fish. Emphasize the differences — (i) Whale breathes by lungs ; a fish by gills. (2) Fish have scales ; whales have not. (3) Fish have cold blood; whales have warm. (4) Young fish come out of eggs ; young whales do not. (5) Whales feed their young on milk, and therefore are mammals. Breathing. — A whale breathes air as other beasts do, and would drown if kept under water too long ; but it can remain under water for an hour at a time. The air that we breathe passes into our lungs and makes our blood pure. If we did not have a constant supply of fresh air our blood would become poisonous and we should die. When the whale comes to the surface it ' spouts ' out from its nostrils a shower of spray made up of the water lurking in them, the vapor of the breath, &c. It then takes in as much air as it can. 198 Longmans' Object Lessons In the body of the whale are a large number of blood-ves- sels of a peculiar kind. In these the blood purified by breath- ing is stored up, and does not pass into the rest of the body till needed. The nostrils are closed under water. ' Why ? ' 'Flippers.' — Mammals generally have four limbs. The hind legs in the whale have almost disappeared, though there are under the flesh small bones showing where they would be. The fore legs (or ' flippers ') take the place of fins in fishes. They are furnished with a kind of hand covered with a thick skin, and are chiefly used to balance the animal. Explain. Tail. — The tail of the whale is horizontal, not vertical hke the tails of fishes. [There will be no need to use the terms ' horizontal ' and ' vertical,' — ' flat ' and ' upright ' will do. Illus- trate with the hand.] It is very large and powerful, and is used in driving the whale through the water. Where found. — Whales live in cold seas. Blubber. — Fish being cold-blooded do not need to be kept warm. The whale is kept warm by a very thick layer of fat (called ' blubber ') which is found beneath the skin, and hinders the heat of the body from escaping. The blubber also makes the animal hght. Show that fat will float on water. Size. — ^The whale is the largest of living creatures. It is from 60 to 70 feet in length, and from 30 to 40 feet in girth. The head is over 20 feet long. Make these numbers concrete. Eyes. — Small ; not larger than those of an ox. Elicit that, living in the water, the whale does not need keen sight. Ears. — Also small. Throat. — Only a few inches across. Sailors say that a penny loaf would choke a whale. Food. — The whale does not need a large throat because it feeds on a kind of ocean snail not more than an inch in length. Whalebone. — Eating small, soft food the whale needs no teeth. The upper jaw is covered all round the edges with horny plates of ' whalebone ' fringed with bristles instead of teeth. Show whalebone. In feeding, the whale, opening its mouth, takes in a mouthful of sea-water and its animal The Bat 199 contents ; then, closing the jaws and pressing the tongue against the roof of the mouth, it drives out the water through the slits between the whalebone slits. Fig. 98. — Head and tongue of Whale, u, tongue (represented much too large) ; b, whalebone plate. The whale ' fishery.' — The whale is sought because of its blubber and its whalebone. A large one is worth more than $5000. Describe as graphically as possible the various inci- dents in the capture. THE BAT [The best illustration will be a bat, living or dead, which may be procured with a little foresight and a little luck. A picture of the skeleton will be useful.] Food. — The bat lives on gnats, moths, &c. These fly about in the dusk on warm days. Elicit thence — (i) That the bat must be able to fly, and to fly faster than the gnats, &c. (2) That, as there are no insects to be caught in winter, the bat must either sleep like the bear, or go to warmer countries like the swallow. Hibernation. — Towards the end of autumn the bat (like the bear) grows very fat. At the first signs of cold weather it retires to some hiding-place, such as a barn or hollow tree. There it hangs head downward by the claws of its hind feet. 200 Longmans Object Lessons folds its wings around it, and falls into a kind of half-dead condition. Not a bird. — By questions and by showing the specimen get out that a bat differs from a bird — (i) It is covered with fur, not feathers. (2) Its wings are made of skin. (3) It lays no eggs. (4) It feeds its young on milk, and therefore is a mamma' Body. — Shape and covering like a mouse's. Teeth. — They have incisor, canine and molar teeth. Ears. — The bat has its ears well developed, although its eyei •iire insignificant. Fig. gg. — Skeleton of Bat. Arms. — Show picture of skeleton. Compare the arms t our arms, but enormously larger in proportion. If our armi were as large in proportion as those of the bat our elbows would reach to our knees while our wrists were on the tops of our heads, our hands would be nearly as long as our bodies, and the joints of our fingers half as long. Birds 20 1 Legs. — The legs are of about the same size as those of a mouse. At the ends of the toes are the claws or hooks by which the bat hangs. From the heel runs a long, pointed bone. Wings. — Compare the bony framework of the arms to the ribs of an umbrella, and the membrane forming the wings to the silk. The wings are made of skin, rather thick near the body, but very thin near the edges. It stretches from the fingers to the shoulders, and from them to the heels and tail. The wings are so large that when the bat is standing on the ground it cannot raise itself by them. It cUmbs up a wall or tree by means of its sharp claws, and then drops, spreading its wings as it falls. Eyes. — ' As blind as a bat.' The bat is not blind, but its eyes, not being formed for use by day, are dazzled by a bright light. Compare to the owl, and in some degree to the cat. Still, the sight of the bat is not very good even in the dusk, but it is able to fly about safely among thick branches of trees in the dark. The sense of feeling in the wings is so very sharp that the animal can, by their help, tell when it is coming near anything. BIRDS [A hen or some other living bird would be very useful for pur- poses of illustration.] Mammals and birds. — By means of questions get from the children some of the differences between mammals and birds, such as — (i) Birds lay eggs ; mammals do not. (2) Mammals feed their young on milk ; birds do not. (3) Mammals generally have four feet ; birds have only two feet, the front limbs being wings. (4) Mammals are generally covered with hair (in some form) ; birds with feathers. 202 Longmans^ Object Lessons (S) Mammals generally live on the ground; most birds spend much time in the air. Bones. — Elicit that in order to rise into the air birds must be light. The bones in mammals are solid and heavy. The Fig. loo. — Contour-feather. Fig. ioi.— Skull of Parrot. Fig. I02.— Head of Eagle. Fig. 103. — Head of Numida. Fig. 104 — Head of Ibis. larger ones are hollow, but they are filled with marrow. The bones of birds are hollow [Show] and filled with air. Strength and lightness are thus combined. Compare with the stalks of corn, the ' backbone ' and ' forks ' of a bicycle or tricycle, and the piers of an iron bridge. Birds 203 Breathing. — The hollows in the bones are connected by openings with certain air-vessels leading into the lungs. When a bird breathes, therefore, air enters all the bones. More than that, the lungs of a bird differ from those of a mammal. The Fig. 106. — Foot of Eagle. Fig. 105. — Foot of Woodpecker. Fig. 108. Foot of Perching Bird. FlG. 107. — Fool of Ibis. Fig. 109 — Foot of Pelican. greater part of the chest, the back, and the spaces between the ribs are filled with air-cells into which the lungs pump air. The great quantity of air inside a bird accounts for — (i) The lightness of the body. (2) The loud and long-continued song of birds. Compare the air-cells to the bellows of an organ. (3) The long time that diving-birds can stay under water. 204 Longmans Object Lessons Feathers.— Let a child feel the living bird, or ask who has felt one. The body is very v^arm. The warmth of birds is kept in by the feathers. Elicit that the warmest quilts are made of down. All birds have feathers, and no other creatures have any. Show the two kinds (' down^feathers ' and 'contour-feathers'), and get out by questions that the former are for warmth alone, the latter for flight also. Beaks. — Nearly all mammals have soft lips and hard teeth. Birds have neither. Their beaks or bills vary with their food. Compare the strong, curved beak of an eagle or a hawk with the short, stumpy beak of a hen and the soft, spoon-like bill of a duck. Feet. — Make a similar comparison between the feet of various classes of birds. FISHES [Show the structure of the gills by means of a dead fish, and their action and the action of the fins and tail by means of a living fish in a glass vessel.] Breathing. — Every part of a fish fits it for living in the water. Mammals, birds, and reptiles breathe oxygen from the air. If kept under water they would die for want of oxygen. Even such an animal as the frog could be drowned in time. In all ordinary water there is a certain amount of air. Heat a little water in a test-tube' and make the children note the many bubbles of air that pass up out of it. If this water were allowed to cool, a fish placed in it would die. Fish, then, breathe the air found in water, but they could not breathe it by means of lungs. Show the gills. Make the children note the red color. Elicit that this is the color of the blood, and that the walls of the blood-vessels must be very thin. Also make the children note how a large surface is obtained by the many walls of the gills. Fishes 205 Fishes open their mouth to take in water, then, closing their mouths, they drive it out over the gills. Show the action of the mouth and gills in the living fish. As the water passes out the air in it acts upon the blood. Cold-blooded. — Question on the two preceding lessons, and make the children see that mammals, which breathe a large amount of oxygen, are warm-blooded, while birds, which breathe still more air, are still more warm-blooded. Hence elicit that fish must be cold-blooded. Let a child feel the living fish. Scales. — Question on the coverings of mammals and birds, and bring out the fact that hair and feathers are wanted to keep in the warmth of the body. Hence elicit that fishes, having no warmth to keep in, need neither hair nor feathers. They are covered with scales. Show, and call attention to the way in which they are arranged. Elicit that if the ' tiling ' were in the opposite direction it would hinder the motion. Let a child feel the living fish to find out that a kind of slime comes off on the hand. This oozes out of small holes in the scales, and acts like oil, keeping out the water. Shape. — Show how the shape of a fish adapts it for cutting through the water. Compare to the shape of a racing-boat and of a swallow's body. Motion. — The motion is caused by the action of the tail-fins. Food. — Most fishes eat other fishes, or whatever living things come in their way. Teeth. — Elicit that their jaws must therefore be furnished with teeth. Show picture of a shark's teeth. Eggs. — Most fishes lay many thousands of eggs. Show (or refer to) the roe of a shad, which is made up of eggs. These are laid in the shallower water. This being warmer than the deeper water, they are hatched there. Also they are less likely to be found and eaten by other fishes. Tell how various fish which live in the ocean make their way up the rivers to lay their eggs. 2o6 Longmans Object Lessons REPTILES [Have pictures of tortoise or turtle, lizard or crocodile, and ser- pents. It would be an advantage to have a real tortoise or lizard. Frogs and toads resemble reptiles in many respects, but differ from them in their mode of growth. The young of a reptile is like its parents from the first ; the young of a frog or toad begins life as a fish. Frogs and toads are therefore classed by themselves as batrachia (Gr. BaTpaxos, a frog).] Creeping animals. — Ask questions about the length of a crocodile's legs, of a turtle's, and of a serpent's. Thus impress on the children the fact that the animals about which they are going to hear must generally creep or crawl. The word reptilis in Latin means creeping ; hence such animals are called reptiles. Cold-blooded. — Let child feel, or ask who has felt a tortoise or lizard. Reptiles are cold-blooded. ' What other class of animals is cold-blooded ? ' ' Why are fishes cold-blooded ? ' Fishes breathe only the air in the water, and as there is very little of that, very little oxygen can get to their blood. Reptiles breathe by means of lungs, but both their lungs and their hearts differ from those of mammals and birds, and are so made that no large quantity of oxygen can get at the blood. Hence reptiles are cold-blooded. Coverings. — Elicit, as in the case of fishes (see p. 205), that reptiles, being cold-blooded, do not need hair or feathers. In animals like the tortoise and turtle the scales make a very hard shell, and in the crocodile they make a covering very dif- ficult to pierce. Senses. — Question on the food of crocodiles and serpents, and elicit that as it is swallowed whole reptiles do not require to have any sense of taste. The tongue is used for feeling rather than for tasting. Refer to the action of a frog's tongue (see p. 145) and a snake's (see p. 150). ' How many eyes has a reptile ? ' Eggs. — All reptiles lay eggs, which are generally hatched by means of the sun. As soon as hatched the young reptile is of the same shape as its parents. Hence frogs and toads are not true reptiles. Insects 207 INSECTS'^ [Sufficient matter is provided for two lessons. Specimens of insects would be useful for purposes of illustration, but as no specimen could be seen by the whole class at once, large pictures of a few typical insects should also be provided.] No skeleton. — ' What is it that feels hard when -we press on a mammal?' [Bones.] ' Are there any bones in a bird V 'A fish f ' 'A reptile ? ' If any insects have been provided, let a child feel them. They have no bones. Rings. — Every insect is made up of thirteen rings. Show- rings in the specimens and on the pictures. [The thirteen can- not be distinguished.] In a large caterpillar (which is an insect in one form) the thirteen rings can be easily seen, but without a microscope only eight or nine could be seen in a fly or a beetle. Let one of the children take a deep breath, and make the rest observe that the chest becomes larger. Elicit that it could not stretch if it were surrounded by unyielding rings. So with an insect. Each ring, therefore, is made up of two semicircles joined by a strong elastic skin, which stretches when the insect is breath- ing or eating. Farts. — Let the children note the deep cuts in an insect. 'How many ? ' [Two.] 'Into how many parts is an insect divided? ' [Three.] Show picture or specimen, and ask into how many parts a spider is divided. [Two.] All insects are divided into three parts — the head, the chest, and the abdo- men. The spider, therefore, is ntit an insect. The word ' in- sect' comes from two Latin words meaning 'cut into.' Legs. — Every insect has six legs, which are joined to the lower side of the middle part of the body (the chest) . Each leg consists of three parts — the thigh, the knee to the ankle, and the foot (with several joints). 1 The greater part of the matter of this lesson is talcen from the Rev. J. G. Wood's Natural History Reader, Book VI. 2o8 Longmans Object Lessons Sometimes it is difficult to see the six legs, as one pair of them is very small. This is the case in the butterfly, for in- stance. Wings. — Every insect has four wings joined to the upper side of the middle part (the chest). Sometimes it is difficult to see the four. In the house-fly, for example, the hinder pair seems absent ; but if we look closely we shall see what look like two little stumps of wings. These are called ' balancers,' and, small as they are, the insect could not do without them. If they are damaged it cannot fly, but flutters helplessly about. When a beetle is walking only one pair of wings can be seen, and they are so stiff' and hard as to appear useless for flight. They are, in fact, useless for that purpose. They are called ' wing-cases,' and serve to protect the flying wings, which, when idle, are packed away beneath them. Elicit that as beetles creep under stones and other hard things, their delicate wings would be injured if deprived of the covers. Skin. — Elicit that as insects have no bones, they would be soon crushed if there were not something (comparatively) hard around them. This is their skin, which, being both hard and elastic, protects them without preventing their bending. Compare the action of the rings in bending to that of a rail- way train rounding a curve. Circulation. — ' What pumps the blood through our bodies ? ' Insects have just under the back a long, narrow vessel each end of which is open. The blood passes through this, works its way between the various organs of the body, and then once more enters it. Breathing. — ' With nvhat do we breathe ? ' Insects have no lungs. If we look through a microscope we shall see in the sides of an insect a number of holes. Each of these leads into a tube which runs the whole length of the body, sending off a number of branches to all parts. The air enters by the little holes in the sides, and thus passes through all the tubes. Eyes. — Refer to the lesson on the Butterfly (p. 151). The eyes there described are typical. Repeat the description. Teeth 209 Sense of smell. — Insects have no noses, but their sense of smell is very keen. Those that feed on dead animals are at- tracted from great distances. It is not known how they can smell ; some people think it is by means of their ' feelers.' Changes of form. — As an illustration Of the development of insects, repeat what was said under this head in the lesson on the Butterfly (p. 152). TEETH [Illustrate the action of ordinary incisors with a knife, of the incisors of rodents with a chisel, of canine teeth with a fork, and of molars by two flat, nearly smooth stones and two flat, rough stones. The skulls or teeth of different classes of animals would be of great use for purposes of illustration. Refer constantly to the children's own teeth.] Kinds of teeth. — Provide a piece of meat, some vegetables, and grains of corn. Show — (i) That the meat and vegetables can be cut with a knife, but that the grains cannot easily be cut. (2) That the grain and vegetables can be ground between stones, but that the meat cannot. (3) That the meat can be torn with the fork, but that the grains cannot, and that the vegetables are more easily cut than torn. (4) That to make a fair-sized hole in a piece of wood a chisel is needed. Our front teeth are formed for cutting. 'Why are cutting teeth always in front?' Compare the edge to the edge of a knife. Animals that gnaw have in front of each jaw two very long chisel-shaped teeth. It is by means of these that a mouse can cut its way through wood. On each side of our cutting teeth is a rounded, rather sharp- pointed tooth. Show. In animals that live on flesh (such as the cat, dog, lion) these teeth are very long and sharp. 2IO Longmans Object Lessons Behind the tearing teeth we have flat teeth, which are used for grinding our food. Illustrate their action. The teeth of mammals are generally of the three kinds named — cutting, tearing, and grinding. Teeth and food. — If we saw the teeth of an animal we could tell on what it feeds, or if we knew on what it feeds we could tell the kind of teeth it has. ' On what does a cow feed? ' ' WAat kind of teeth must it have in front ?^ ' Why ? ' 'And what Fig. iio.— Skull orPorcupine (a gnawing animal). '^^'"■'^ "J ^^'^ '^^^^ ^^ have behind? ' ' Why? ' Ask similar questions about the cat (flesh), pig ^flesh and vegetables), and other familiar animals. Flesh-eating mammals. — Show skull or picture of the teeth of a flesh-eating animal. Call attention to the very long and sharp tearing (canine) teeth. Show that the cutting teeth are very small. ' Why ? ' Perfectly flat grinding teeth would not Fig. III. — Teeth of Kangaroo Rat. be of much use for flesh ; the grinding teeth in the cat and similar animals have sharp and jagged edges. Flesh- and vegetable-eating mammals. — In the bear and other animals that live on flesh and vegetables some of the Teeth 211 grinding teeth have smoother crowns. There is also a difference in the action of tlie jaws. In flesh-eaters the jaw moves up and down only. '/« how many ways does our lower jaw move ? ' Show that when grinding food our jaw moves sideways. The jaw of the bear moves sideways as well as up and down. Vegetable-eating mammals. — ^The cow has broad cutting teeth in the lower jaw, and in the upper jaw neither cutting nor tearing teeth. (See p. 59.) The grinding teeth are broad and flat. In some cud-chewing animals (the deer, for instance) the grinding teeth have little knobs of enamel (the hardest part of the tooth) on their surface. ' What is the use of these ? ' Gnawing mammals. — Show skull of mouse, rabbit, or hare. Call attention to the two long, sharp, chisel-like teeth in front of each jaw. These wear away with constant use, but they grow again at once. Further- more, the front of the tooth is made of harder material than the back ; hence the back wears away faster and the edge is always keen. Gnawing animals do not need tearing teeth. The food which they cut with their front teeth is ground with their back teeth. Mammals without teeth. — Some mammals have no teeth. Refer to the lesson on the Whale (p. 198) ; mention the food ; show that teeth are not wanted, but that a strainer is. The ant-eaters, again, living on insects, do not need teeth. Fig. 112. — Crown of tooth of Deer, show- ing the enamel cres- cents. Fig. 113. — Skull of Ant-eater (a toothless animal). Birds. — Birds have no teeth, their food being ground in the gizzard. To make the grinding more thorough many birds swallow little stones. Reptiles. — Reptiles swallow their prey whole. Hence they need teeth to hold, not to tear or grind. Refer to what was 212 Longmans' Object Lessons said in the lesson on Snakes (p. 149). Some reptiles have no teeth. Fishes. — Fishes also need teeth, chiefly to hold their prey. There is not so much variety in the teeth of fishes as in those of mammals. COVERINGS Why we need clothes. — By questioning on the preceding lessons remind the children that the oxygen of the air which we breathe, getting into the blood, causes the warmth of our bodies. We wear clothes to keep in the warmth of our bodies. ' What do people wear in iiery cold countries ? ' [Furs.] Winter and summer clothes. — Question about the changes which we, living in temperate climates, make in our clothing with the changing seasons. Animals cannot put on overcoats in the winter or leave them off in the summer. ' IVhat do they do ? ' Take the horse and sheep as examples. ' JVhat keeps a horse warm ? ' Ask whether the children have noticed how thick and rough a horse's coat becomes in winter, and how they shed their coats as warm weather approaches unless they are clipped. Refer to something similar in the lesson on sheep (p. 63). 'Do human beings ever cut their own hair to prevent its coming out ? ' Elicit that our warm clothes are made of the wool of the sheep, and that if we had to wear them in summer we should feel very uncomfortable. So would the sheep if it had to wear its wool. Consequently, towards the end of spring the wool is shorn. If the sheep were not shorn the wool would drop off. Now take a few typical animals and show how their cover- ings fit them for their surroundings. The elephant. — The elephant lives in warm countries and has a thick skin. It therefore does not require fur or hair. In a wild state it is constantly moving through thick woods, and if it had any hair it would catch in the underwood. The same remark applies to the pig, which has no hair and not many bristles. Cotyledons 213 The beaver. — Refer to what was said about its fur in the lesson on the Beaver (p. 104). The whale. — Ehcit that as our clothes would not keep us warm in the water, a mammal like the whale has no fur. 'How is it kept warm ?' Refer to the lesson on the Whale (p. 198). Protective coloring. — -Refer to what was said on this point in the lesson on the Tiger and the Lion, the Hare, and the Crocodile (pp. 94, 95, 103, 146). Birds. — Refer to what was said on the temperature of birds (p. 204), and elicit that as birds must fly and as their blood is very warm their covering must be both light and warm. 'We say, "As light as a • "I ' And if we want very warm quilts we line them with down. Thus impress on the children that feathers fulfil both requirements. Fishes and reptiles. — By means of questions connect the fact that fishes and reptiles are cold-blooded with the fact that they have no hair, fur, feathers, or other warm covering. C : Lessons on Elementary Botany COry£££)ONS [A week or ten days before the time for giving this lesson the teacher should plant a number of broad beans and grains of wheat or oats, in the garden if the season is suitable, in flower-pots if it is unsuitable. The flower-pots should be placed in a moderately warm room, and the soil kept moist. Two or three days later the teacher should plant some more beans, and two or three days later some more. Just before the lesson the germinated specimens must be pulled up for examination by the class. Also before the lesson soak some beans and wheat (or oats) for a few minutes in boiling water, and then distribute them among the children.] Cotyledons. — Let the children examine the broad bean. At one end is a black stripe [^z'/«/«^]. This shows where the 1 The technical terms enclosed in brackets are for the teacher, not the class. 214 Longmans' Object Lessons seed was attached to the carpel in which it was enclosed. Let the children squeeze the soaked bean, and a little moisture will come out through a very small hole [in the hilum]. Let the children next remove the skin. They will see that it contains two large thickened lobes or leaves flattened on the inner and rounded on the outer side, and hinged. When the lobes are separated carefully there will be seen close by the hinge upon the margin of the inner face of one of them a rudimentary root and bud. The little root is called a Fig. 114- — Broad Bean. ^,seed with one cotyledon removed ; c, remaining cotyledon; kn, pin- mule; w, radicles. .5, germinat- ing seed; 7/, hilum; j^, petiole; h, main root. Fig. 115. — Longitudinal .section of Oat. C, the single cotyledon : G^ plumule; R, radicle. Fig. 116. — Germina- tion of Oat; rt, cot- yledon; d, radicle; f, plumule. radicle. It points towards the opening in the hilum, and growing forms the root. Show in the specimens. The little bud is called a plumule, and growing forms the stem and leaves. Show. The fleshy lobes or seed leaves are called cotyledons. Plants which, like the bean, have seeds with two are called dicotyledons. The grain of wheat or oat is rather small for examination. Its structure will be made clearer by a drawing on the black- Roots 2 1 S board. It will be seen to contain only one cotyledon. Plants which have such seeds are called monocotyledons. Distinctions. — Most of the plants of the world are dicotyle- dons. Of the flowers examined in preceding lessons the but- tercup, mustard, phlox, catnip, pea, daisy, and dandelion belong to this class. The tulip and daffodil are monocotyledons. (i) Ask a few questions about the number of organs in the first class of flowers, and lead the children to see that the parts are usually in fours or fives (or multiples of four or five) . Similarly get out that in the second class the parts are usually in threes (or multiples of three) . (2) Next show the venation of the leaves. Dicotyledons are net veined, and monocotyledons are generally parallel veined. Cut across a thick twig of any ordinary tree ; also cut across and along a piece of cane. The first is a dicotyledon and the second a monocotyledon. Make the children observe the differences. (3) The first has bark, the second none. (4) The first has central pith, the second none. (5) The wood of the first is arranged in layers around the central pith. The wood of the second is arranged in fibres parallel to each other. ROOTS [Illustrate the first part of this lesson by showing either the roots of the plants named or other roots similar in form,] Forms. — Call attention to some of the more common forms of root, as — (1) Conical ; like the carrot or monkshood. (2) Spindle-shaped [fusiform] ; broadest in the middle and tapering towards the two ends, as in the radish. (3) Turnip-shaped [napiform] ; globular, with a tapering end, as in the turnip and some kinds of radish. (4) Fibrous ; giving off a number of slender branches, as in the grass. 2l6 Longmans' Object Lessons (5) Tuberous; when the fibres are swollen in an egg-shaped manner, as in an orchid \orchis Morio\ A Fig. 117. — Conical root of the Carrot. Fig. 118. — Spindle-shaped Fig. 119. — Turnip-shaped root of the Radish. root of the Radish. (6) Palmate ; when the tuber is divided so as somewhat to resemble the fingers of an outstretched hand, as in another orchid, the common orchis maculata. Fig. 120. — Fibrous root of a Grass. FiG. 121.— Double tuber (a, b) of Orchis Morio. (7) Tufted [fasciculated] ; when there are a number of tubercles or fleshy branches, arranged in a bunch, as in the dahlia. Roots 217 (8) Knotted (nodulose) ; when the fibres are enlarged at the ends only, as in the dropwort. Fig. 122. — Double palmate tuber («, b) of Orchis odoratissitna. Functions. — (i) To hold the plant firmly in the ground. Amphfy. (2) To convey food to the plant. A plant derives some of Fig. 123.— Tufted root of Dahlia. Fig. 124.— Root of White Clover, having small tubers. its food from the air, and some from the ground. The root cannot take in any substances from the soil so long as they remain solid, but it ' sucks ' up substances that have been dis- solved. Hence elicit the need of water to the life of a plant. 2i8 Longmans^ Object Lessons (3) Some of the substances in the soil will not dissolve in water, but will dissolve in an acid. The sap of some plants is acid, and some of it, passing out through the roots, may change the food into the form in which it can be absorbed. (4) Some roots, such as the turnip and all those mentioned in the lesson on edible roots (p. 215), store up food. These, except some varieties of the radish, bear no flowers the first year, but the big root stores up the substances on which, during the second year, the flowers will live. Hence they are called ' biennials.' After the plant has flowered and the seed ripened the root is found to be withered and shrivelled up. [When cultivated for food these are pulled up during the first year.] STEMS Stem. — Stem is the name given to the part of a plant which bears the leaves and the flowers. Two kinds. — Stems are either woody or herbaceous. Illus- trate by specimens. Roots and stems. — A few of the differences between roots and stems may be pointed out. (i) Stems grow upward, roots downward. (2) Roots are white ; the stems of herbaceous plants are generally green. (3) The 'growing-point' of the root is covered with a root- cap, and of the stem with young leaves (buds). This may need some little explanation. If the tip of an uninjured root-fibre be examined through a magnifying-glass, the extremity of the fibre will be seen covered with a closely- fitting sheath, or root-cap. The cap is worn or withered a:s it forces its way through the soil, but it is constantly renewed from the inside by the growing-point. The stem always begins in a bud. The first or primary stem begins in the plumule. Show again in the broad bean. (4) The stems have leaves, flowers [and other appendages^ Stems 219 differing from it in structure. The root simply has branches, the branches being the same in structure as the original root. Fig. 125. — Longitudinal section through apex of a root; wh^ root-cap; M, pith. Forms. — (i) Make sections of different stems. Most of them will be circular, but a few may be angular. Fig. 126. — Sections of angular stems. (2) Most stems are erect, but some trail on the ground and some climb. 220 Longmans Object Lessons (3) Climbing stems attach themselves by rootlets (like the ivy) or by tendrils (like the pea), or they twine around their support (like the bindweed and the hop) . Fig. 127. — Stem of Convolvulus arvensis, i^lG. 128. — Stem of Hop. [Note the different directions in which they twine.J (4) Runners. — These may be seen in the strawberry. A branch springing from a plant creeps along the ground, strikes Fig. 129. — Runner of Strawberry. in the soil, and produces leaves and roots, thus forming a new plant. Stems 221 (5) Nearly the same kind of thing happens in gooseberries and currants. Gardeners imitate it in the process of ' layering,' when they bend down the branch into the soil, thus causing it to take root. [In the case of gooseberries and currants the ' runner ' is called a stolon.^ Fig. 131.— Sucker. Fig. 130. —Stolon. (6) Suckers. — In the gooseberry the branch that takes root springs above the soil. In the rose such branches spring beneath the soil, run a short distance, strike roots, and send up stems. These are called ' suckers.' (7) Root-stock [rhizome]. — In the iris or flag and in other plants there is a thickened stem which creeps either on the soil or just below it, giving off leaves from the upper surface and roots from the lower. (8) Creeping stem. — This is thinner than the root-stock, but otherwise like it. It is seen in the sand sedge and in couch grass. (9) Tuber. — The tuber is an underground stem or branch much swollen by starch, &c. It possesses leaf-buds. In the Fig. 132. — Rhizome of Rolomnn's Seal : fl, ter- minal bud from which will be developed next year's stem; ^, this year's stem; <:,(/, scars of the stems of previous years. 222 Longmans^ Object Lessons potato these are the ' eyes.' When the potato is earthed the growth of the underground branches or tubers is encouraged. Fig. 133. — A six-weeks-old Potato plant, grown from seed: a, b, the upper branches (cut oflQ ; d^ cotyledons. In the axils of the cotyledons are developed the underground branches ^, e, which bear tubers,_/, g ; A, true roots. (10) Bulb. — Show in the onion. (11) Corm. — A much more solid kind of bulb, seen in the gladiolus, snowdrop, crocus, &c. The bulb and the corm are seen only in monocotyledons. Dicotyledons and monocotyledons. — Review the differences already learned between the stems of these two classes. LEA VES [Two Lessons.] Forms, &c. — Review with proper illustrations the lessons on Leaves (pp. 1 15-123). rnnctions. — (i) To absorb food for the plant.— ^ome of the substances on which plants live are taken up by the roots from the soil, but the carbon which they need is taken up by the Flowers and Fertilization 223 leaves from the carbonic acid in the air. Thus a gas which is a waste product of animals affords nourishment to plants. This process goes on only in the light, and is dependent upon the green matter in the leaf. In darkness the plant cannot develop the green matter, which is called chlorophyl, and therefore can- not absorb carbonic acid gas. (2) As a storehouse of food. — The leaves of many plants, particularly certain seed leaves (see lesson on Cotyledons, p. 213), store up food for future use. (3) As a breathing organ. — The process of respiration goes on in plants as well as in animals, but in a different way. (4) As an organ of transpiration. — A large portion of the water taken in by the roots of the plant escapes by the leaves. This process can be made visible. Pluck up a small plant by the roots. In the middle of a card make a hole large enough to allow the roots to pass through. Place the card over a tumbler of water, thus allowing the roots to dip into the water. Over the leaves place an empty tumbler, and this in a little while will be covered with the drops of transpired water. The transpiration of plants causes the air in the neighbor- hood of woods to be moist. Sometimes when a forest has been cleared the rainfall diminishes greatly and droughts are caused. FLOWERS AND FERTILIZATION [Two lessons.] [The first part of this lesson is a general summary of the lessons on Flowers (pp. 161-172). Every part should be illustrated by means of actual specimens.] Whorls. — In a complete flower there are four circles of organs. Each circle is called a whorl Calyx. — -The outer whorl is the calyx, which is made up of sepals. These are generally green, but sometimes (as in the fuchsia, larkspur, and nasturtium) they are colored. They are generally arranged in one circle, but in the strawberry there are two, and in the cotton plant three. 224 Longmans' Object Lessons Fig. 134. — Pappus of Dandelion. A remarkable form of calyx, known as the pappus [Latin for thistledown], is found in some composite (and other) flowers. The sepals become hair-like, and are often very much enlarged upon the fruit, as is seen in the head of the dandelion after flowering. Corolla. — The next whorl is the co- rolla, which is generally brightly colored and often odorous. The parts com- posing it are called petals. When the calyx and the corolla are alike in color (as in the tulip and the daffodil) they are called the perianth. Stamens.-^The next whorl consists of stamens. Each stamen, when com- plete, is made up of three parts — (i) The filament, the stalk which' attaches it to the rest of the flower. ' (2) The anther, a little knob (really a box) on the top of the filament. (3) T}\& pollen, a fine powder within the anther. Pistil. — The inner whorl is called the pistil, which is made up of Carpels. — Each carpel, when complete, consists of three parts — (i) The ovary, ihe swollen lower part. It is a hollow box containing one or more rounded bodies called ovules. (2) The style, a stalk standing on the ovary, and holding (3) The stigma. Generally the carpels of the pistil are united tegether — either entirely, as in the hly, or the ovaries are united while the styles and stigmas are free, as in the sea-lavender (Fig. 146). Fertilization. — The stamens and pistil are the most im- portant parts of a flower, for without them fertilization could not take place, and no fruit or seed could be produced. Before fertilization can take place the pollen of the stamens must come in contact with the pistils. Flowers and Fertilization 225 First a grain of pollen settles on the stigraa and adheres to it. Then a portion of the inner part of the grain protrudes through Fig. 135.— Pistil of Lily. Fig. 136. the outer part. This prolongation is known as a pollen tube. The pollen tube grows down through the style and enters the ovary. Cross-fertilization. — In very many cases stamens and pistils are found on the same flower, but, as a rule, the ovary of one flower must be fertihzed by pol- len from the stamens of another. This process is called cross-fertilization. The pollen is carried from one flower to an- other in various ways. (1) By the wind. — The flowers of the hazel (the catkins), for example, are of two kinds — 'staminate' flowers, having stamens and no pistils, and ' pis- tillate ' flowers, having pistils and no sta- mens. When the pollen is fully ripe it is shed from the anthers and scattered by the wind. The greater portion of it is wasted, but some falls on the stig- mas, fertilizing them. The oak, the fir, the yew, and various grasses and cereals are thus fertilized. Fig. 137. — Longitudinal sec- tion through ovary at time of flowering: a, stig- ma: bf pollen grains; c, pollen tube; d^ wall of ovary. 226 Longmans Object Lessons In all these cases the pollen is produced in far greater quantity than is actually needed for fertilization. Refer to the lesson on Fig. :i3g. — Staminate flower of Hazel. Fig. 140.— Pistillate flower of Hazel. Indian corn (p. 72) and elicit that the tassels are the staminate flowers while the ears of corn come from ^Q pistillate flowers. (2) By insects. — The brilliant colors and sweet smell of flowers attract insects. While they are en- deavoring to obtain the honey they come in contact with the anthers. Grains of pollen adhere to their bodies, and are caught on the sticky stigmas of the next flowers visited. Wind-fertilized plants, not needing to attract insects, have small and inconspicuous flowers. (3) Some plants are fertilized by birds, and a few by snails. Fig. 138. — Hazel branch with stam- inate and pistillate flowers. [The two large catkins are the stami- nate flowers; the pistillate flower is at the top.] FRUIT AND SEED [Two lessons.] Fruit. — The term 'fruit' is applied to the ripe pistil, formed in various ways, with or without other parts of the flower. (i) Some, such as the pea, bean, vetch, consist of the pistil alone (slightly altered). Fruit and Seed 227 (2) Some consist of the pistil changed entirely into a juicy mass, as in the grape, or partly, as in the peach and plum. (3) Some, such as the gooseberry, currant, apple, and pear consist of the pistil and calyx. A portion of the calyx may be seen at the top of these fruits. (4) In the hazel nut the ' nut ' is formed from the pistil and the husks from the bracts. The bracts form the cup of the acorn. (5) The fleshy part of the strawberry is the enlarged recep- tacle of the flower, the pips being the true fruit. (6) The mulberry, pineapple, fir-cone, and figs are made up of a number of pistils formed by separate flowers all combined into one mass. Two kinds of fruit. — Fruits are divided by botanists into two classes : — (i) Those that open to scatter the seeds. (2) Those that do not open. Fig. i+i.^CapsuIe FlG. 142.— Capsule of Primula. of Poppy. Fig. 143.— Pea. Fruits that open. — When a fruit opens so that the seeds fall out it is called a capsule. Various forms of capsule are seen in the primula, poppy, pea (or bean), peony, mustard, &c. Fruits that do not open. — Among fruits that do not open may be noticed — (i) The stone fricit \_drufe'], as the peach, cherry, &c. These consist of three parts : {a) the skin, {b) the fleshy part, (f) the stone (with the seed inside) . 228 Longmans' Object Lessons (2) The berry, where the seeds are enclosed in a pulpy matter within a covering formed by the wall of the ripe ovary Fig. 144. — Fruit of Peony. alone, as in the grape and potato- apple ; or by the ovary in combi- nation with the calyx, as in the jr.o. .45._Fruit of Mustard. gooseberry and currant. [The calyx is the brownish, leafy part at the top cut off before the fruit is eaten.] Fig. 146. — Longitudinal section through drupe of Peach. Fig. 147. — Transverse section through a Gooseberry. (3) The apple and pear are a kind of berry formed by the enlargement of the receptacle of the flower. The core is Fruit and Seed 229 the true fruit. There are usually five cavities containing the seeds. The scales on the top are the remains of the calyx. Fig. 148. — Longitudinal section through an Apple, Fig. 150. Strawberry. (4) The achene^ a dry, single-seeded fruit, such as is seen in each floret of the sunflower and dandelion, also in the buttercup and strawberry. Fig. 151. — Hazel Nut. Fig. 152. — Acorn. (5) The nut and acorn are a kind of achene in which the seed has a hard shell partly covered with the bracts. The seed. — The seed is usually contained in the fruit. Give ^ Pronounced a'-keen. 230 Longmans' Object Lessons examples. The fir is an illustration of a ' naked ' seed — that is, of a seed not contained in the fruit. To be complete the seed must contain the ruditnent of the young plant — the embryo. Sometimes (as in the pea and bean) the embryo forms nearly the whole of the seed ; sometimes (as in the Indian corn) it forms only part. In these cases there is a separate store of nourishing matter called albumen, which is taken up by the plant in the early stages of its growth. FLOWERLESS PLANTS Types. — The plants which we have hitherto been observing all have flowers, but there are a number of common plants without any. Examples : — Ferns, horse-tails, mosses, mush- rooms, lichens, sea-weeds. Ferns. — ^The leaves are generally called fronds. They are rolled up when young, and when older they are thrown off periodically. The stem, which is surrounded by their withered bases, constantly increases in length. On the under side of some leaves will be found small, brownish, seed-like bodies. These are the spore-cases \j:po- rangia\. Each contains within it when ripe what looks like very fine dust. This dust is made up of the spores. When they fall to the ground they germinate, but do not immediately produce fresh ferns. [The complete process of reproduction is too complex for description to young children.] Horse-tails. — ^These are found in temperate countries. They have erect, hollow, and jointed stems. The stems are of two kinds, fertile and barren. The fertile stem is generally un- branched, and has at the end a cone-like catkin, consisting of scales having spore-cases on the under side. The barren generally give off slender-jointed branches in whorls from the joints. [Development from spores, as in the case of ferns.] Mosses. — Minute leafy plants with slender stems, bearing spore-cases upon erect hair-like stalks. They grow in tufts or in soft carpet-like masses. Flowerless Plants 231 Mushrooms. — A full grown mushroom consists of a vertical stem supporting a cap. On the under side of the cap are the gills, which radiate from the stem but do not touch it. Many mushrooms are poisonous. The edible mushroom has gills at first of a rose color, afterwards changing to a dark color. The spores are almost black. Lichens. — These may be seen as a gray or greenish-yellow crust growing on old walls, trees, fences, &c., or on the ground amongst mosses. Sea-weeds. — This family [the AlgcB\ includes not only sea- weeds but the green plants found growing in fresh water in the spring and summer. 232 Longmans' Object Lessons NOTES OF A LESSOlSr ON THE CAT Age of Children — 7 to 9. Illustrations. — ^A living cat ; a saucer of millc. Heads Food Structure Matter Cats, if left to them- I selves, live on mice, rats, birds, and other crea- tures, vifhich they catch alive. Feet. — The fore paws have five claws each, the hind paws four, which are not so sharp as those on the fore paws. Each claw has a sheath of thick, hard skin into which it can be drawn back. Method There is a soft pad under each toe, and one under the middle of each foot. Show the cat. ' What does pussy live on? [Milk, meat, &c., will probably be given.] ' If we did not give her any food what would she live on?' Emphasize the fact that cats catch their prey alive. The re- mainder of the lesson will show the adaptabiUty of their structure. Let a child count the claws. Call attention to their shape, their sharp- ness, and the difference between those on the fore paws and those on the hind paws. ' What are the fore claws used for?' Bring out adapta- bility of their shape to the work of holding a living animal. * What does the cat catch with the hind claws? ' [Nothing.] ' What are they used for, then ? ' Let a child feel that the claws are not firmly fixed at the end of the toes. Show the sheatfi, and illustrate its purpose by making the cat project and retract its claws. ' Suppose the cat's claws were blunt, what would happen when she tried to catch a mouse?' 'What would happen to the claws if they rubbed against the ground as the cat walked ? ' Hence elicit the use of the sheath. Let the children see the pads. ' What would a mouse do if it heard the cat coming ? ' Hence elicit the use of the pads. See p. 17. This is practically the same lesson as that given in another form on p. 55. Notes of a Lesson on the Cat 233 Notes of a Lesson on the Cat — {continued). Heads Matter Method Structure Teeth.—lw. the front of its mouth the cat has four long, sharp teeth, curv- ing inward. The other teeth are also pointed. Tongue. — The tongue is rough, having a great number of little hooks pointing backwards fixed all over it. Eye. — The pupil of a cat's eye varies grtatly in shape and size. At night it is large and round, but in a bright light it is a narrow slit. Whiskers. — The cat has long whiskers. These act as feel- ers. Fur. — ^The cat's fur is not oily. Show the teeth. * What would a mouse try to do when tlie cat had caught it?' 'With which teeth does the cat hold it?' Hence elicit adaptability of front teeth. Bring out that back teeth are formed for tearing, not chewing. * How does a cat get all the meat off a bone?' [By licking.] Let the cat lick the hand of a child. [To induce her to do so, put a little milk on it.] Explain the use of the roughness. Let the cat lap some milk, the chil- dren watching the spoon-hke action of the tongue. Compare pupil to a hole in a closed shutter. Elicit effect of altering the size. ' When do mice come out of their holes?' 'When does the cat want to see best?' Show whiskers. Let a child touch the ends of seme. He will perceive that they are stift, and notice that the cat feels him. *!rihould we feel if the ends of our hair were touched? ' ' Why does a blind man use a stick ? ' * Why do we hold our hands before us when walking across a room in the dark? ' * When does the cat go about most?' Hence elicit need of feelers, and explain action of whis- kers. Let a child stroke the cat. 'What does father do to his boots on very wet days?' [Oil them.] *Why?' * There being no oil in a cat's fur, what will water do to it?' ' Does the cat dislike being out in the rain?' INDEX A IR, pressure of, 1 80 Alloys, 81, 88, 89 Animals as illustrations, 18 — teeth of, 209 — coverings of, 212 Answers to questions, 31 Ant, 156 Arrangement of object lessons in courses, 8, 9 matter of object lessons, 12 Ass, 6l Attraction, capillary, 193 — magnetic, 194 "DARLEY, 69 " Barometer, 183 Bat, 199 Bear, 100 Beaver, 104 Bee, 152 Bell-metal, 90 Birds, 201 — of passage, 107 Blackboard drawings, 22 — summary, 36 ' Bookish ' language, 26 , Brass, 81, 88 Bricks, 50 Britannia metal, 90 Bronze, 89, 90 Burning candle, 133 Buttercup, 165 Butterfly, 150 r^AMEL, 98 Candle, chemistry of, 1 33 Capillary attraction, 193 Carbonic acid gas, 131 Carlyle on Natural History, 5 Cat, 54, 232 Catnip, 166 Chocolate, 76 Claims of science to be taught, 3 Clouds, 142 Coal-gas, 136 Cocoa, 75 Coffee, 76 Comparison of flowers, 170 Composite (or compound) flowers, 169 Copper, 88 Cork, 114 Corn, 69 Corrugated iron, 91 Cotton, 113 Cotyledons, 213 Courses of object lessons, 9 Coverings of animals, 212 Cow, 59 Crocodile, 146 235 236 Longmans Object Lessons Cross-fertilization, 225 Crystals, 43 Curriculum principles, i J)AFFODIL, 167 Daisy, 169 Dandelion, 170 Diamond, 80 Dog, 56 Donkey, 61 Duck, 68 Ductility, 82 — order of, 83 Dutch metal, 84, 89 PARTH-WORM, 160 Edible roots, 73 — vegetables, 74 Effects of heat, 1 74 Elasticity, 51 Elephant, 97 Eliciting and telling, 14, 32 Ellipses; 31 Emery, 80 Emphasis, 35 Engine gauge, 191 Equilibrium of liquids, 189 Experiments as illustrations, 23 pERNS, 230 Fertilization of flowers, 224 Filters, 46 Fishes, 204 Flowerless plants, 230 Flowers, 161, 223 Fly, 15s Fog, 142 Fountains, 191 Frog, 143 Fruit and seed, 226 Fusion. 81 LIQ QALVANIZED iron, 91 Garden pea, 75, 168 Gases, 173 XJARD and soft substances, 80 Hare, 103 Heat, effects of, 1 74 Hen, 66 Herring, ill Horse, 58 Horsetails, 230 House-fly, 155 Hydrogen, 132 TLLUSTRATION of object les- sons, 16 — objects, 17 — models, 21 — pictures, 21 — experiments, 23 Indian corn, 72 Indiarubber, 53 Insects, 207 Iron, 85 JACKAL, 97 Jacotot on telling, 32 T ANGUAGE of object lessons, 25 Lead, 86 Leaves, 115, 222 — parts of, 115 — venation and framework, 1 1 7 — simple and compound, 118 — shapes, 120 Leaves, edible, 122 Lecturing and teaching, 27 Lemon, 77 Lichens, 231 Lion, 94 Liquids, 173 Index 237 LIQ Liquids, pressure of, 178 — equilibrium of, 189 ATAGDEBURG hemispheres, 189 Magnets, 181 Maize, 72 Malleability, 83 Mammals, 196 ■Manufactures, illustrations of, 19 Matches, 135 Matter of object lessons, 10 — arrangement of, 12 Melting-point of various substances, 82 Mist, 142 Models as illustrations, 21 Mosses, 230 Mouse, 65 Museum, school, 20 Mushrooms, 231 Mustard, 161 J^ITROGEN, 130 Notes of lessons, 14 — form of, 16, 232 QAK, 78 Oats, 70 Objects as illustrations, 17 Object lessors, preparation for science, 7 substitute for science, 7 Object lessons, subject of, 8 courses of, 9 — • — matter of, 10 notes of, 14 illustration, 16 language, 25 . questions, 27 telling and eliciting, 14, 32 emphasis, 35 SCI Object lessons, summary, 36 recapitulation, 36 Orange, 77 Ostrich, 109 Oxygen, 126 pEA, 75, 168 Pens, 93 Pewter, 81, 89 Phlox, 163 Pictures as illustrations^ 21 Kg, 63 Pins, 91 Plants as illustrations, 19 Plastic substances, 49 Porosity, 44 Pressure of liquids, 178 the air, 180 Pump, 184 — suction or lifting, 185 — force, 188 QUESTIONS, 27 — purpose of, 28 — rules for, 29 — answers to, 31 J^AIN, 143 Recapitulation of object les- sons, 36 Reptiles, 206 Rice, 71 Roots, 215 — some edible, 73 CALT-MAKING, 43 School curriculum, principles, 1 — museum, 20 Science, should it be taught? i — its claims to be taught, 3 — when it should begin, 5 238 Longmatis' Object Lessons SEA Sea-weeds, 231 Seeds of- plants, 229 Sheep, 62 Snail, 158 Snakes, 148 Snow, 143 Soft and hard substances, 80 Solder, 87, 90 Solids, liquids, and gases, 173 Solvents and iiolutions, 41 Spider, 157 States of matter, 173 Steel, 8r, 86 Stem of plants, 218 Subjects of instruction, choice of, I object lessons, 7 Sugar, 47 Summary of object lessons, 36 Suspejisioti, 44 Swallow, 107 Syringe, 185 . yEA, 123 Technical terms, 11, 25 Teeth of animals, 209 Telling and eliciting, 14, 32 Tenacity, 83 Thermometer, 177 ZIN Things, not words, 12 Tiger, 95 Tin, 89 Toads, 143 Tobacco, 124 Trade winds, 141 Tulip, 167 Type-metal, 81 T JNGRAMMATICAL answers, 32 VEGETABLES, some edible, 74 Ventilation, 138 Vocabulary of children, 26 ^ATER-LEVEL, 190 Waterworks, 192 Whale, 197 Wheat, 69 When science teaching should begin, 5 Winds, 140 Wine- tester, 182 Wolf, 96 Worm, 160 7INC, 90 NOTES BY TEACHERS LOMGMANS, GREEN, &= CO.' S PUBLICATIONS. LESSONS IN ELEMENTARY SCIENCE. LONGMANS* OBJECT LESSONS. Hints on Pre- paring and Giving Them. With full Notes of Com- plete Courses of Lessons on Elementary Science. By David Salmon, Principal of ttie Training College, Swansea ; Revised and. Adapted to American Schools by John F. Woodhull, Professor of Methods of Teaching Natural Science in the New York College for the Training of Teachers. i2mo. 246 pages. 152 Illustrations. Mailing Price, $1.10. PART I. — HINTS ON PREPARING AND GIVING LESSONS. Should Science be Taught? — When should Science Teaching Begin? — Subjects of Lessons — Matter of Lessons — Notes of Lessons — Illustrations — Language — Questions — Telling and Eliciting — Emphasis — Summary — Re- capitulation. (Pp. 1-36.) PART II. — NOTES OF LESSONS. First Year. — {a) Lessons on Common Properties, {b) Lessons on Common Animals, (c) Lessons on Plants. Second Year. — {li) Lessons on Common Properties. (.5) Lessons on Animals, (f) Lessons on Plants. Third Year. — {a) Lessons on Elementary Chemistry and Physics, {b) Les- sons on Animals, (c) Lessons on Flowers. Fourth Year. — (a) Lessons on Elementary Physics. {]>) General Lessons on Natural History, (f) Lessons on Elementary Botany. Notes of a Lesson on the Cat. — Index. (Pp* 41-238.) " If these lessons are given at the rate of one a week, and thoroughly re- viewed from time to time, they will provide work for four or five years. Teach- ers and pupils should make large use of cyclopedias and other sources of in- formation. Hence the book offers a course of elementary science for lower grades, leading up to the specific study of zoology, physiology, botany, chem- istry, physics, and geology, which are to be undertaken in the higher grades." " A four years' course in science is here scheduled that embraces botany, zoology, chemistry, and physics. I he four subjects are studied througtiout the course, the lessons being graded to suit the stage of intellectual development of the child. The plan adopted is emmentlv objective and inductive. . . throughout the book new knowledge gained is made the stepping-stone to some- thing higher, co-ordinating not only the facts of any one science but also the various sciences themselves. The process of comparing objects, in order to de- termine rheir similarities and differences as a basis of classification, is most ad- mirably developed. . . . Manuals heretofore have, as a general rule, treated each object as if it were isolated from all else in the material world, and as if the facts concerning that particular object were of prime importance. This book subordinates ttie knowledge gained of particular objects to the use of ob- jects as a means of exercising the powers of observation, comparison, and gen- eralization." — Educational Review, N. V. LONGMANS, GREEN, & CO., 15 East Sixteenth Street, New York. LONGMANS, GREEN,^&' CO.' S PUBLICATIONS, LONGMANS' NEW SCHOOL ATLAS. Consisting of 28 quarto and 10 octavo Colored Maps (and 20 In- sets). Edited by G. G. Chisholm, M.A., B.Sc, and C. H. Leete, A.M., Ph.D. Engraved by Edward Stanford. With a very full Index of over 100,000 Names. Imp. 8vo. $1.50. Longmans' Mew School Atlas is intended, as its name implies, for use in schools. It offers a series of maps which it is believed will be found fully ade- quate for the most advanced school work, affording the material for careful and prolonged study, and a basis for a broad knowledge of geographic principles and facts. With this end in view three groups of maps have been prepared : first, nine maps exhibiting the leading facts oi physical geography and human distribution as pertaining to th^zoorldas a whole ; second, eleven maps pertaining to North America, and more particularly to the United States and Canada, physical, political, geological, climatic, industrial, historical, and on population ; and third, twenty-one maps (and seventeen insets) ot other parts 0/ the world in their physical and political aspects. The Geological Map of the United Slates and Canada was revised by Mr. W. J. McGee, of the U. S. 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Chisholm, M.A., B.Sc, Author of "Handbook of Com- mercial Geography,'* "A Smaller Commercial Geography," etc., etc., and C. H. Leete, A.M., Ph.D., Fellow of the American Geographical Society. Fourth edition, revised, large i2mo, with 70 Illustrations. 384 pj^es. $1.25. The aim of this text-book is to present in an attractive form those facts of geography that are really foundational, i.e., those that are most important to know, and are most effective as discipline. All countries and regions of the world are, therefore, not treated upon a uniform plan or according to a rigid outline, but that which is most distinctive and characteristic in each is presented with due relief. And, in order that pupils may realize that to understand is in geography equally, if not more, important than to memorize, sperial promi- nence is given to the relation of cause and effect. 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Probably the best book of the kind ever published in our language, and ought to help in improving the instruction of our schools in geography. Messrs. Chisholm and Leete's book is valuable for its method, and it is this fact which entitles it to the attention of teachers. " — Boston Beacon. " It has a system of cross references thai is very valuable and constantly reminds the pupil that all are parts of a whole. It does not merely state farts, but attempts to show a cause for each phenomenon, so that the study oi geography is not mere memoriter work." — Educational Courant. LONGMANS, GREEN. & CO.. 15 East Sixteenth Street, New York, LONGMAN'S, GREEV, &= CO.'S PUBLICATIONS. 17 LONGMANS' ATLAS OF ANCIENT GEOGRA- PHY. Twenty-eight colored Maps, selected with a view of facilitating the study of ancient geography in connection witli history. Edited, with an Introduction on the Study of Ancient Geography, by the Rev. George Butler, Principal of Liverpool College. Imperial 8yo. $2.00. Much the cheapest Atlas of its quality. The maps are selected with a view to facilitating the study of ancient geography in connection with history, parti- cular attention being paid to those maps which illustrate classical authors. Great care has been taken in the construction of the maps, the object being to combine the elements of distinctness, accuracy, and simplicity, with due regard to proportion, both in the physical and political features. HANDBOOK OF COMMERCIAL GEOGRAPHY. By George G. Chisholm, M.A.., B. Sc. ; Fellow of the Royal Geographical and Statistical Societies. 8vo. 522 pages. $4.00. *' The volume will form not only a useful work of reference, but will also be an indispensable handbook to tearhers of commercial geography : and will also prove of the greatest use to pupils who may pursue the highest branches of modern business education." — Chamber of Commerce yournal. " Taking the book as a whole, probably no handbook of commercial geog- raphy in any language is equal to it." — Proceedings of the Royal GeograpkicaJ Society. SCHOOL TEXT-BOOK OF COMMERCIAL GEOGRAPHY. By George G. Chisholm, M.A., B.Sc. i2mo. 216 pages. 90 cents. This book is in the main an abridgment of the author's " Handbook of Com^ mercial Geography." In making the abridgment, endeavor has been made to retain as much as possible of the matter that seemed fitted to present the lead- ing facts of international commerce in such a way as to impress the memory. The description of countries is confined to features of importince in relation to commerce. Like the larger book, this text-book is divided into paragraphs for the sake of making frequent cross references. The references are made by printing the number of the paragraph referred to in thick type in parentheses, thus (345). " A treatise of the highest order and greatest possible utility. The descrip- tion of the various countries of the world, arranged under the general grand divisions or continents, is at once accurate and learned, as well as practical and interesting." — Education. " Commercial and business colleges might use them to great advantage as regular text-books." — Science. LONGMANS, GREEN, & CO., 15 East Sixteenth Street, New York. SHAKESPEARE'S PLAYS FALCON EDITION " The ' Falcon ' Edition has earned a reputation for 'scholarship, taate, and judg ment. The notes arc in all cases excellent. Everything that is likely to present any dif&culty is explained clearly, accurately, and not verbosely ; and familiarity is shown both with the writings of the Elizabethans and with the Shakespearean scholarship ol to-day." — Journal of Education. " A particularly pure text, with introductory remarks, glossaries, and notes of an excellence for which this edition is renowned." — Educational Times. " An edition now well known among teachers and students, and which offers much instruction and enjoyment to the thoughtful reader. The editing is characterized by conscientious care, judgment, and skill." — Schoolmaster. " Mr. Beeching's Julius Cxsar is not only an excellent school-book, but a model of good Shakespeare editing for all readers ; and his Merchant of Venice is no less." — Academy. The following volumes, each with Introduction, Notes, and Glossary, are now ready. Price 35 cents each play. Julius Caesar. By H. C. Beech- ING, Eector of Yattendon, and late Exhibitioner of Balliol College, Oxford. ByH. The Merchant of Venice. C. Beechikg. King Henry IV. Part I. By Oi.rvEK Elton, late Scholar of Corpus Christi College, Oxford. King Henry IV. Part II. By A. D. Innes, M.A., late Scholar of Oriel College, Oxford. King Henry V. By A. D. Innes, M.A. King Richard III. By W. H- Payne Smith, M.A., Senior Stu- dent of Christ Church, Oxford; and Assistant Master at Rugby School. King John. By Olivee Elton. Twelfth Night. By H. Howard Ceawley. Much Ado About Nothing. By A. W. ^'EEITY, M.A., late Scholar of Trinity College, Cambridge. Coriolanus. By H. C. Bebching. Taming of the Shrew. By H. H. Ceawley. King Richard II. By E. K. Chambers, B.A. The Tempest. By A. C. LiDDELL, M.A. Others in ■pre/paration. LONGMANS, GREEN, & CO. 15 East Sixteenth Street, NEW YORK LONGMANS, GREEN, ^ CO,' S PUBLICATIONS, LONGMANS* SCHOOL GRAMMAR. By David Salmon. Part I., Parts of Speech ; Part II., Classification and Inflection ; Part III., Analysis of Sentences ; Part IV., History and Derivation. With Notes for Teachers and Index. New Edition, Revised. With Preface by E. A. Allen, Professor of English in the University of Missouri. i2mo. 272 pages. 75 cents. *' . . . One of the best working grammars we have ever seen, and this applies to all its parts. It is excellently arranged and perfectly graded. Part IV., on History and Derivation, is as beautiful and interesting as it is valuable — but this might be said of the whole book." — New York Teacher. "The Grammar deserves to supersede all others with which we are ac- quainted." — N. Y. Nation, July 2, 1891. PREFACE TO AMERICAN EDITION. It seems to be generally conceded that English grammar is worse taught and less understood than any other subject in the school course. This is, doubtless, largely due to the kind of text-books used, which, for the most part, require methods that violate the laws of pedagogy as well as of language. There are, however, two or three English grammars, that are admirable com- mentaries on the facts of the language, but, written from the point of view of the scholar rather than of the learner, they fail to awaken any interest in the subject, and hence are not serviceable for the class-room. My attention was first called to Longmans' School Grammar by a favorable notice of it in the Nation. In hope of finding an answer to the inquiry of numerous teachers for " the best school grammar," I sent to the Publishers for a copy. An examination of t^he work, so far from resulting in the usual dis- appointment, left the impression that a successful text-book in a field strewn with failures had at last been produced. For the practical test of the class- room, I placed it in the hands ot an accomplished grammarian, who had tried several of the best grammars published, and he declares the results to be most satisfaLtory. The author's simplicity of method, the clear statement of facts, the orderly arrangement, the wise restraint, manifest on every page, reveal the scholar and practical teacher. No one who had not mastered the language in its early his- torical development could have prepared a school grammar so free from sense- less rules and endless details. The most striking feature, minimum of precept, maximum of example, will commend itself to all teachers who follow rational methods. In this edition, the Publishers have adapted the illustrative sentences to the ready comprehension of American pupils, and I take pleasure in recom- mending the book, in behalf of our mother tongue, to the teachers of our Pub- lic and Private Schools. ^ Edward A. Allen. University of Missouri, May, 1891. MR. HA1,E'S school, BOSTON. " I have used your Grammar and Composition during the last year in my school, and like them both very much indeed. They are the best books of the kind I have ever seen, and supply a want I have felt for a good many years. '" — Albert Hale, Boston, Mass. LONGMANS, GREEN, & CO., 15 East Sixteenth Street, New York. LONGMAISrS, GREEN', ^ CO," S PUBLICATIONS. 23 LONGMANS' SCHOOL GRAMMAR.— O/'/A^/CA^^. girls' high school, boston, mass. '' When you put Longmans' School Grammar in my hands, some year or two ago, I used it a little while with a boy of nine years, with perfect satisfac- tion and approval. The exigencies of the boy's school arrangements inter- cepted that course in grammar and caused the book to be laid aside. I'o-day I have taken the book and have examined it all, from cover to cover. It \% simply a perfect grammar. Its beginnings are made with utmost gentleness and reasonableness, and it goes at least quite as far as in any portion of our public schools course it is, for the present, desirable to think of going. The author has adjusted his book to the very best conceivable methods of teaching, and goes hand in hand with the instructor as a guide and a help. Grammar should, so taught, become a pleasure to teacher and pupil. Especially do I relish the author's pages of ' Notes for Teachers,' at the end of the book. The man who could write these notes should enlarge them into a monograph on the teaching of English Grammar. He wnnld, thereby, add a valuable contribu- tion to our stock of available pedagogic helps. 1 must add in closing, that while the book in question has, of course, but small occasion to touch disputed points of English Grammar, it nevt-r incurs the censure that school grammars are almost sure to deserve, of insufficient acquaintance with modern linguistic science. In short, the writer has shown himself scientifically, as well as peda- gogically, altogether competent for his task," —Principal Samuel Thurber. high school, fort wayne, ind. " . . . . It is not often that one has occasion to be enthusiastic over a school-book, especially over an Enghsh Grammar, but out of pure enthusiasm, I write to express my grateful appreciation of this one. It is, without exception, ^he best English Grammar that I have ever seen for children from twelve to fifteen years of age. It is excellent in matter and method. Every page shows the hand of a wise and skilful teacher. The author has been content to present the facts of En£;lish Grammar in a way intelligible to children. The book is so intelligible and so interesting from start to finish that only the genius of dulness can make it dry. 1 here are no definitions inconsistent with the facts of our language, no facts at war with the definitions. There are other grammars that are more '' complete " and as correct in teaching but not one to be compared with it in adaptation to the needs of young students. It will not chloroform the intelligence." — Principal C. T. Lane. HIGH SCHOOL, MINOOKA, ILL. " We introduced your School Grammar into our schools the first of this term, and are highly satisfied with the results. In my judgment there is no better work extant for the class of pupils for which it is designed." — Principal E. F,. Adams. newark academy, newark, n. j. " We are using with much satisfaction your Longmans' School Grammar, adopted for use in our classes over a year since. Its strong points are simplic- - ity of arrangement, and abundance of examples for practice. In these par- ticulars I know of no other book equal to it." — Dr. S. A. Farrand. *^* A Prospectus showing contents and specimen pages may be had of the Pub- lishers, LONGMANS, GREEN, & CO., 15 East Sixteenth Street, New York. LONGMANS, GREEN, &■ CO.'S PUBLICATIONS. ELEMENTARY PHYSIOGRAPHY. An Introduc- tion to the Study of Nature. By John Thornton, M.A. With lo Maps and i6i Illustrations. Crown 8vo. 256 pages 80 cents. This volume is intended to serve as an introduction to Science. It suppliee such a knowledge of ttie facts and laws of Nature as is implied in the express- ive term Physische Erdkvnde — an acquaintance with the physical phenomena of the Earth. It contains chapters on Matter and its Properties, Gravitation and Specific Gravity, Cohesion and Chemical Affinity, Work and Energy, Chemical Action ; Kocks, their Composition, Classification, and Arrangement ; Interior of the Earth, Volcanoes, etc.; the Sea, the Polar Regions, and Ice of the Sea; the Atmosphere, Evaporation and Condensation, Dews, Mist, Fog, Rain, and Snow ; the Sculpture of the Land, Weather, and CUinate. Changes in the Earth's Siirface ; Magnetism and Electricity of the Earth, Shape and Movements of the Earth, etc. The third Edition contains a short account of recent researches on Dew, and gives a simple explanation of Telescopes. ST. PAUL'S SCHOOI,. "I have been using Thornton's Elementary Physiography for two years with my classes beginning the study of science. I find it a most admirable book and can certainly recommend it from a personal knowledge of it. . I shall continue its use." — DR. J. Mii,NOR CoiT, Concord, N. H. ADVANCED PHYSIOGRAPHY. By John Thornton, M.A. With 180 Illustrations, 6 Maps, and a colored Plate of Spectra. Crown 8vo. 350 pages. $1.40. Contents: I. The Celestial Sphere — Constellations — Definitions and Ex- planations — II. General Survey of the Solar System — III Light and Astro- nomical Instruments IV Spectrum Analysis — V, The Physical and Chemical Constitution of the Sun — VI. Description of Ihe Planets — VII. The Moon, Its Dimensions, Orbit, Rotation, Phases, Physical Conditions — Eclipses — VIII. The Tides — IX, Comets and Meteors — X. The Motions of the Earth — Changes in the Orbit — XI. Measurement of the Surface, Size, and Shape of the Earth — Mass of the Earth — Determination of Latitude and Longitude- XIL Celestial Measurements — XIII. Gravitation and Celestial Masses — XIV. Stars and Nebulae — XV. Atmospheric and Oceanic Movements — XVI. Terrestrial Mag- netism — XVII. Cosmogony, Secular Cooling of the Earth, Secular Changes of Climate. APPENDIX; The Greek Alphabet— Time Constants— Trigonomet- rical Functions — Principal Elements of the Solar System — The Transit Circle — Geological Importance of Tides — Age of the Earth — Geological Chemistry. THE AMATEUR TELESCOPIST'S HAND-BOOK. By Frank M. Gibson, Ph.D., LL.B. With Illustrations and Descriptive Catalogue of 46S Celestial Objects. Crown 8vo. $1.25. Contents : I, The Telescope ; Its Principles and Powers — II. Testing the Object Glass, Eyepieces, Tubes — III. The Stand — IV. Accessories of the Telescope — V. The Care of the Telescope — VI. The Use of Ihe Telescope — VII. Observation, Stars, Nebulae, the Sun and Moon — VIII Observation, Continued, The Planets — IX. Prices of Telescopes and their Accessories. Celestiai, Objects: Alignment Stars — A Descriptive Catalogue of 468 Celestial Objects. LONGMANS, GREEN, & CO., 15 East Sixteenth Street, New York.