l'-<-.l ill 1 f^m: i^5'' m m ^■!iVt' Qass Book ^ U X \V. K. No. 443. Issued Dec. 31. WIO. U. S. DEPARTMENT OF AGRICULTURE, If 5 WEATHER BUREAU. BULLETIN T. FROST AND TEMPERATURE CONDITIONS IN THE CRANBERRY MARSHES OF WISCONSIN. Prepared uiidtM- tlic ilirection iif WILLIS L. MOORE, Chief of Weather Bureau, I By HENRY J. COX, Professor of Meteorolosn-. II WASHINGTON: GOVKKNMEXT FKINTING OFFICE. 1910. ; ..• A /") c^^ />^l .% ^\ JAN 20 191! i 9 Page. ArKXOWLEDGMENTS '^ InTHODIX'TIOX " Cultivation of cranberries conlined to three States ~ (Occurrence of low temperatures and frost in moorlands 7 Cultivating, draining, and sanding S Enemies to the cranberry croji - Comparison of temperatures in Massachusetts, Xew Jersey, anil Wisconsin H) Flooding to ward off frost 11 Previous knowledge of low temperatures in the Wisconsin bogs 12 Beginning of the investigation lo Characteristics of stations at Cranmoor, Berlin, and blather 17 Equipment of the Mather station 18 Equipment of the Berlin station 24 Discrssiox OF the proiilem - 26 .Minimum temperatures in shelters an ami liiOT. 37 .Vii- temperatures and soil temperatures at Station 7 and Station 7a, Mather, Wis., September, 19i)6 43 ilinimum temperatures at the coldest and at the warmest points on tlie bog, Mather, Wis Hi Comparison of mininuim temperatures at Station 1, in shelter, and on bog at Stations 3 and n, Mather, Wis. . b2 Curves of air and soil temperatures at Stations 1 , H, and .5, blather. Wis., 1907 Mi Minimum temperatures at the coldest and at the' warmest points on the bog at Berlin, Wis ri8 Minimum temperatures over dry and moist sand, Stations 3 and 4, Berlin, Wis til Minimum temperatures over peat bogs, heavily vined and thinly vined, Berlin. Wis., September, 190ti.. 62 .Minimum temperatures over peat bogs and sanded bogs, thermometers exposed at ri inche- nbove the surface, at Cranmoor, Mather, and Berlin 63 Readings of exposed mininiums at various elevations over bog and upland. Stations 2 and 9, Mather, Wis. . 6.5 Comparison of wind movement over upland and marsh, and effect on temperature, Mather, Wis., 1907 7.S Exposed minimum thermometers over peat and sanded bogs at the surface, and at elevations of 5 inches and .36 inches, Berlin, Wis 76 Maximum and minimum temperatures at different elevations, Station 9, Mather, Wis 78 .\verage minimum temperatures for the season of 1907 for all locations, together with soil temperatures, Mather, Wis 78 Relation between dew-point and minimum temperature 84 Dew-point readings at Berlin 88 Fog o\'er marshes, and low teiniieratures 88 Special observations on critical nights at the Berlin marsh, September, 19iHi 89 Effect of frost on the cranberry 91 Disadvantage from reflowing 92 Special data in connection with forecasting frost in the cranberry marshes 92 Discussion of daily weather maps anil local conditions in connection with frosts in tin- Wisconsin bogs in 1906 92 Discussion of daily weather maps and local conditions in connection with frosts in the Wisconsin bogs in 1907 95 Conjparison between temperatures in the bog at Mather, Wis., and at United States Weather-Bureau ofHce, La Crosse, Wis 110 Temperature conditions in the bogs during the seasons of 1908 and 1909... 114 Temperature of the water in the reservoir 114 CONCLISIOX 116 .Advantages gained from sanding, draining, and cultivating 116 .\ study of the general and local coinlitions necessary for frost in the marshes 117 (3) ILLUSTRATIOT^S. Page. Fi 7. Station 1, Mather, Wis. Instrument shelter on upland near dwelling-. Photograph made in 190(5... 18 8. Station 2, Mather, Wis. In bog over sphagnum moss and long grass outside cranlierry marsh- 19 9. Station 3, Mather, Wis. Newly sanded, thinbj' vined 19 10. Station 4, Mather, Wis. Newly sanded, heavily vined 20 11. Station 5, Mather, Wis. In uncultivated bog 21 12. Station 6, Mather, Wis. Old sanded, heavily vined - - 21 13. Stations 7 and 7a, Mather, Wis. In .scalped section and on moss adjoining 22 14. Station 8, reservoir, showing wide ditch and floating bog, Appleton marsh, Mather, Wis 23 15. Station 9, Mather, Wis. In garden on upland 23 16. Station 10, warehouse, Appleton marsh, Mather, Wis. Anemometer on cupola. Sunshine recorder on comb of building 24 17. Fitch marsh, Berlin, Wis., showing car track on bog, dwellings, warehouses, and shanties 25 18. Station 5, Fitch marsh, Berlin, Wis. In ferns and canebrakes 25 19. Temperature curves for Stations 3 and 4, Mather, Wis., September 23 to 30, 1906 40 20. First figure, traces showing average hourly soil temperature for the season of 1907 at a depth of 3 inches and 6 inches, Station 3, Mather, Wis -iO Second figure, traces showing average hourly soil temperature for the season of 1907 at depths of 3 inches and 6 inches. Station 5, IMather, Wis - -10 21. (iraph of maximum and exposed minimum air temperatures and soil temperatures in bog, Mather, Wis., 1907 57 22. Graph of maximum daily soil temperatures in bog, Mather, Wis., 1907 58 23. Thermograph and anemometer records on July 27, 1906, Mather, Wis 7.t 24. Thermograph record on the marsh, Berlin, Wis., noon. August 30, to noon, September 1, 1906, show- ing effect of passing clouds on temperature '^5 25. Traces of thermograph in shelter \PERATLRE AND FROST CONDITIONS IN THE CRANBERR^ MARSHES OF WISCONSIN. IXTRODUCTIOX. CuUh-atioii of cranherries confned to tJiree States.— The cultivation of cranberries in the United States is confined mainly to three States— Massachusetts. New Jersey, and Wisconsin. In Massachusetts the oranherry-growing region in turn is hniited almost entirely to the counties of Ph-mouth. Barnstable, and Bristol: in New Jersey, to Cape May. Atlantic, Gloucester, Bur- lington. Ocean, antl Monmouth counties: and in Wisconsin, to Wood. Jackson, Juneau, and Momoe counties in the Wisconsin River Valley, and to Waushara and Winnebtigo counties in the Fox River Valley. (Fig. 1 for map of Wisconsin.) For several years there luxs betai a mai-sh in the village of Cameron, Wis., and recently one was started in the Lake Superior region near the town of Ashland, Wis. The cultivation is slowly extemling to Michigan and Minnesota, and even Oregon, but the cultivated marshes in the three states last named are at present comparatively of no importance. There are, of coui-se. wild cranberry mai-shes in several of the Northern States, but the berries pickeil theivfrom are seldom sufficient to supply even local needs. They are of little consequence a^ compareil with the fruit produced in the cultivated mai-shes of Massachusetts, New Jersey, and Wisconsin. The cultivation of cranberries a^ an industry is by far older ami more siict-essfid on Cape Cod than elsewhere. Nearly every bog. whether large or small, on the Cape, has been con- verted into a cranberry mai-sh, and there we find the highest state of cultivation, the bogs being almost invariably sanded, well drained, and free from weeds. The Massachusetts bogs are individually small as compared with those found on the extensive moorlands oi New Jersev and Wisconsin: and often one cranberry marsh in ila^sachusetts is made up of several small sections. That of the Federal Cranberry Company, near South Carver, Mass., which annuallv produces about 10.000 to 14.000 barrels of berries from a total area of ISO aci-es. is composed of IS little bogs, separated naturally by hard land, but connected, nevertheless, artificiallv by ditches for the purpose of flooding: while, on the other hand, the Wisconsin moorlands ai'e extensive and often stretch for many miles. The Wisconsin River Vallev. the chief cranbeirv- growing section of the State, comprises an area of about SOO square miles. o50 of which are mai-sh land, the remaining portion being •' islands ' or hard land. In topography, the moor- land sections of Xew Jersey more nearly resemble those of Wisconsin than they do those of Massachusetts. The average :Massaoluisetts crop is about 300,000 barrels, while New Jersey and Wisconsin contribute 150,000 and 7.5,000 barrels, respectively. Occurrence of low temperatures and frost in moorlaruis. — During clear cool nights the air usually is much colder over bottom lands, where the cranberry grows, than on neighboring slopes and uplands. This is especially true when but little wind or a calm prevails. During such nights the ground loses its heat rapidly by ratliation, and the air lying immediately above is cooled. When cold heavy air lies over uplands ami slopes it gradually settles through gravity to lower levels, being replaced by warmer air brought from above, which is in turn cooled. In fact, a gradual descending flow is established from the uplamls to the valley, so that the cold air of the hilltops is di-ained away. Quite frequently crops in bottom lands suffer severely from frost, while on neighboring uplands the temperatures are not injurious. It is well known that the tobacco fields on the slopes of the Connecticut River often escape injurv when damag- mg frosts occur lower down. The cranberry, moreover, has its habitat only in the bottom (7) 8 lands where frost is most likely, but protection may be afforded by covering the bbg witii water stored in adjacent reservoirs. Cultivating, draining, and sanding. — Protection to a considerable extent may also be obtained by cultivating, draining, and sanding the cranberry marsh. In bottom lands the vegetation is generally dense and the soil damp. Leaves and grasses are excellent radiators, STATE OF WISCONSIN. Scale of Miles. to 20 JO 40 so so 70 Milvf'aiikee MAP SHOWING PRINCIPAL COUNTIES CRANBERRIES ARE 6R0WN. IN WHICH G.fl.%9/,o Fig. 1. — Map showing principal counties in which cranberries are grown. and consequently lose their heat rapidly. The heat lost by radiation passes thi'ough the air, and does not warm it if the air is dry; but when the air is moist some of the heat is absorbed. Moreover, where the vegetation is dense, the soil beneath is screened from insolation, so that it is heated but little by the sun during the day, and has but a small supply of heat stored up. As a consequence the temperature of air Iving over a field with a dense growth of vegetation is relatively low during any cold clear night. Cultivation, by reducing the amount of vegetation, permits greater heating of the soil during the daytime, and consequently there is a larger store of heat to give out at night. The peat soil found in bottom lands, on account of its capillarity, brings water to the surface, and the cold produced by the evaporation of this moisture is considerable. This is especially the case where the drainage is poor. Ditches, run at frequent intervals in the marsh, serve to drain the water from the surface and to reduce the amount of evaporation; and, at the same time, to conduct water of comparatively high temperature from adjacent reservoirs to the bog Avhen frost threatens. The moisture at the immediate surface may also be reduced by sanding — placing a layer of sand on the surface of the peat — because sand, almost wholly lacking in capillarity when coarse, does not bring the water to the surface. Moreover, sand on account of its low specific heat is warmed more easily, and acts as a conserver of heat. A sanded surface absorbs solar radiation tolerably well, and gives out heat by radiation only slowly. It cools largely by con- duction to the atmosphere, thus serving to modify night temperatures by heating the air Ij'ing above. Very few of the Wisconsin bogs have been sanded, and many have a rank growth of vege- tation, grasses and ferns often attaining a height of 2 feet or more. Frequently canebrakes and sagebrush are found. The uprights from the cranberry vines are usually more than 6 inches in height, and occasionally 12 inches or more. The growth of the vines is very rank, and the marshes are seldom kept clean, so that even when the vines are laden with berries, one's attention is attracted to the vegetation rather than to the fruit. On the other hand, the Cape Cod marshes are invariably sanded and the vines are thin, the uprights seldom reaching a height of more than 5 inches, as the coarse sand employed dwarfs the vines. The berries, moreover, are usually so plentiful that one hardly notices the vines. The contrast between the Massachusetts marshes and those of Wisconsin is so pronounced that the growers in Wisconsin have been said to raise vines, and those on Cape Cod berries. This statement has some foundation in that the yield per acre on the Cape is about double that in Wisconsin. The marslies in Xew Jersey perhaps take middle ground between those in Massachusetts and Wisconsin. They are usually well cultivated, but only infrequently sanded. In fact, not 15 per cent of the New Jersey bogs are sanded. The growers there prefer to confine the cranberry culture to the natural peat soil, believing that it produces a crop of better quality than does a sanded bog, and that the expense of sanding is not justified by the increased returns. The right kind of sand is near at hand for the Cape Cod growers, but it is not easily available for many of the growers in New Jersey and Wisconsin. A coarse sand, resembling gravel, is ordinarily used, fine sand packing too hard and being therefore valueless. The drainage in the bogs of Cape Cod, moreover, is excellent, the marshes during the growing season usually being as dry as an ordinary prairie — in strong contrast to the dampness of the Wisconsin bogs. The little need for refiowing on the Cape permits the growers there to keep the ditches dry during the sununer season, but the Wisconsin growers are obliged at all times to keep a certain amount of water in the ditches in order to facilitate refiowing when frost is expected. The Wisconsin marshes are consequently more or less damp during the entire season. Cultivation, moreover, is practiced on Cape Cod, preventing the rank growth of vegetation and weeds that screen the soil from the sun's rays. Cultivating, draining^ and sanding thus serve to cause higher soil temperatures in the daytime, and, as a result, relatively higher air temperatures at night. These facts — the advantages gained from cultivating, draining, and sanding — were quite apparent to the WTiter after a preliminary investigation; ami an effort will be made in this report to show in detail, by figures, the relation between the air temperature and the character of the soil and vegetation lying beneath. Enemies to the cranberry cro^j.— The great enemies to the cranberry are frosts, floods, droughts, worms, and fire; and whOe the damage from frost is seldom very great in ilassa- chusetts and New Jersey, frost is the berry's greatest enemy in Wisconsin. The meteorologist is 10 chiefly interested in the frost problem, as far as cranberry growing is concerned. However, floods and freshets during the gro^nng season frequently work havoc with the cranberry crop, and it was because of the floods in the s])ring of 190.S that the crop in the vicinity of Berlin, Wis., was nearly a complete failure. In that year it was not possible to coiupletely draw ofl' the winter flow until the last of June, instead of in May as usual, and consequently the crop of ber- ries in some bogs was confined to the tops of the vines while in others the crop was a total failure. Such surplus of water not only destroys the crop of the current year, but also weakens the vines so that they show the injurious effects for several years afterwards. The freshets of the spring and summer of the year 1906 were responsible for great damage to the New Jersey crop. If a flood covers the marsh during extremely warm weather there is damage to the vines and berries from scalding, the reflection of the heat from the surface of the water cooking the berries until they resemble baked apples. This liability to damage is ahvays considered by the growers in reflowing their marshes in oi'der to drown the vine and fruit worms, and it is necessar}" to select a period of cool and cloudy weather, if possible, so as to get the best results with the least injury. Damage is also liable frf)m lack of water, not only in the insufficient supply available for reflowing the marsh for frost protection or otherwise, as in Wisconsin in 1909, but because in seasons of great drought the vines become parched and extensive fires are likely to occur. As a result of the drought of 1894, 95 per cent of the vines in the Wisconsin Eiver valley were de- stroyed by fire, but the marshes have since been replanted. In 1909, 60 to 75 per cent of the Wisconsin crop was lost in the severe frosts of September because of lack of \\'ater for reflowing. Comparison of temperatures in Massachusetts, New Jersey, and Wisconsin. — From a study of the temperature conditions in the three states during the growing season it is evident that the temperature is usually much lower in Wisconsin than in the eastern cranberry-growing sections. From a comparison made between temperature readings observed in shelters on hard land at Plymouth, Mass., Whitebog, X. J., and Mather, Wis., in the midst of the respective cranberry districts, for the months of May and September, 1 906 — critical months in the cranberry industry and fairly typical ones — it was found that the minimum temperature at Plymouth averaged higher by 5.1° in May and 4.5° in September than at Mather; while at Whitebog, for the same months, the minimum temperature averaged S.l° and 7.6°, respectively, higher than at Mather. The average readings at the respective stations were as follows: Mather. \\ is Plymouth, Mass AVhitebog, N. J. May. September. o 41.9 47.0 oO.O 1 50.5 53.0 68.1 The difl'erences between these averages represent approximately the relation between the minimiuii temperature readings in the bogs in the various States, although for ]nirposes of comparison it was found necessary to use readings made on hard land. The first frost in the Xew Jersey bogs in autumn usually occurs from two to three weeks later than in W^isconsin. In 1906, for instance, the first light frost at Whitebog occuiTed on October 8, and a heavy frost was not rei)orted until October 11, while in Wisconsin the first frost was noted September 14" and the first killing frost on September 27. Frost is so damaging in the Wisconsin bogs that means of protection from it must be the first provision made by the cranberry grower. Damaging frosts invariably occur there in the month of May, often in June, rarely in July, occasionally in August, and invariably again in tiie month of September; while midsummer frosts are miknowu in the East and seldom occur in the month of June. In the East severe frosts do not occur so late in the spring or so <^arly in the autumn; and consequently the seasons in Cape Cod and Xew Jersey are much longer than in Wisconsin. The season in the latter state is quite short, and it is only during a year in which "About two weeks later than the average. 11 till' crop season has a temperature far al>ove the normal that the cranberry grower in Wisconsin, w itliout means of protection from frost, can hope to gather even a fair crop. Flooding to ward off frost. — It is apparent from the foregoing that, although the Wisconsin crop is usually smaller than that of either Massachusetts or New Jersey, it has special need of proj)er protection from frost, and hence the need of accurate frost warnings. The large majority of the Wisconsin and New Jersey marshes and a limited number of those in Cape Cod are connected with vast reservoirs, which are used for flowing the bogs in winter in order to prevent wmter killing, and for reflowing tluring tlie growing and jiicking season for the purpose of warding ofl' frost. In fact, as stated above, the first thought of the Wisconsin grower is to provide ample water supply. Some of the bogs in Massachusetts have no watersupply, even for winter flowing, but all the bogs in Wisconsin and nearlj' all those in New Jersev have ample supply for this pur- pose. Growers usually tiu-n on the winter flow in November and keep it on throughout the entire winter. Some Wisconsin growers take the winter flow oft' again about April 15, but the majority retain it until after the first of May, and a few mitil the last of May. Those who keep the flow on until late in May do so believing that the water prevents the hatching for that season of the fruit worms with which the marshes have been afflicted. Some growers who take the winter flow off the marsh early reflow during Jime and keep the water on for a few days, if a ]:)eriod of cool weather prevails, in order to guard against the fi-uit worm. It is supposed that the eggs are laid in May along the dams, and that if, thi'ough drowning, they are prevented from hatching during the month of June, the worms will not apj)ear that season. As a period of three months is sufficient to mature the crop, should the water be retained until June 1, the cranberries would ordinarily be ripe for picking about September ] . Frecjuent reflowing, however, if the fruit is set, injures the vines and the berries as well. Moreover, in flowing and reflowing, damage is sometimes done to the crop by lime or otlier impiu'ities in the water. Most of the Wisconsin marshes can be reflowed in about four hours, but there are a few in that state that can not be satisfactorily flooded in anticipation of frost. In the marshes of the East, of course, as stated above, frosts are not as serious as in Wisconsin because of their more favorable geographical location. On Cape Cod, moreover, where intensive farming is practiced in the shape of santling, draining, and weeding, there is not the same need for reflowing to ward off frost. Onlv about 30 per cent of the Cape Cod bogs can be reflowed as a means of warding off frost, and this can not be done twice in one week in more than 10 per cent of these bogs during a season of normal rainfall. In New Jersey somewhat better conditions as regards water supply prevail. Many of the bogs, as the excellent one at \Miitebog, for instance, usuallv have ample water supply. With such limited water protection in Wisconsin as is usuallv available in Massachusetts bogs, success in the industry woiddbe quite impossible. In reflowing a marsh the amount of water used depends upon the severit}' of tlie frost expected ; sometimes it is sufficient merely to raise the water in the tlitches ; at otlier times to bring it up to the surface of the marsh ; and, in extreme cases, to completely cover the vines and berries. The Appleton marsh at Mather is a typical Wisconsin bog, and is usually provided with ample water supply. (Figs. 2, 3.) The reservoirs, both upper and lower, are largely floating bogs. Wide ditches connect the reservoirs with the cultivated sections and smaUer ditches run through the sections from 80 to 100 feet apart. Water is usually present in the ditches to a depth of 1 to 2 feet, the surface of the water averaging perhaps about 12 inches below the surface of the marsh itself. These ditches are provided with gates to regulate the flow from the reservoirs. There is also a gate at the foot of the marsh (marked "B" on Fig. 3), which is shut during flooding and opened later in order to drain the water oft". "Wliile 3 acres of reservoir AIT. generally sufficient for flooding 1 acre of vines, yet the acreage of the marshes of Wisconsin usually has about one-tenth planted in vines, ami the rest is given over to reservoirs and protec- tion of water rights. 12 Previous knowledge of low temperatures in the Wisconsin bogs. — It has been known»f()i- many years that the minimum temperature in the Wisconsin bogs on clear cool nights falls far ])elo\v the readings of tlie instruments at the nearest Weather Bureau station, and that frost often occurs in these bogs when there is no evidence of it on hard land. Prof. Willis L. Moore, now Chief of the United States Weather Bureau, was the first forecaster to give this subject special attention. It was in 1S9.3, wliilo in charge of the Milwaukee office, that lie visited several of the bogs in the Wisconsin River valley. Later, other officials from time to time have visited these marshes. Professor Whitson, of the Wisconsin Experiment Station, undertook an investi- gation in 1904 in connection witli the Branch Experiment Station located at Cranmoor. As a preliminary to the investigation started by the United States Weather Bureau, efforts were made to secure reliable data from various Wisconsin growers relative to the occurrence of frost and freezing temperatures diu'ing pn^vious years, but it was fomid that ver\' few of them had kept a record of any value. Som'^ data, however, have been furnished by Mr. C. H. Johnson, manager of tlie Wyatt and Purdy marsh at Valley Junction. His statement shows tliat during Flf.,. *.;. --A|-iiK.'liin mar-li. MuIIkt. Wi--.. siiuwiuL,' ii..nh ,...;,,-;: >;; :>m.,. .iI.m; hi;i-:: where lower reservoir is local ud. View from uplnnd. Directly beyond the brush i^ loc;ilfd the main section. Shelters at Stations 3 and 4 appear an the extreme left. the period of twenty years from 1SS5 to 1904, inclusive, frost usually occurred in the summer tit Valley Jimction before the end of August. In 1885 heavy frost was recorded on August 22, in 1S90 light frost occurred as early as August 10, and heavy frost in the same year on August 23. In several years of this period frost occurred more than once during the month of August, but Mr. Johnson has no record of its occiu'ring in July; however, in a few instances, frost has been observed in that month by other growers. The frost which occurred on June 11, 1903, in Wisconsin, did much damage, and, as a result, less than half a crop was harvested in that year. Some of the growers lost nearh' all, although others, because of their location and better facilities for protection, secured nearly a full crop. The frost of August 8, 1904, reduced the crop of berries to aliout 60 per cent of that iisually secured. No damage resulted in marshes which had been flooded before the frost. Ihifortunately, some of the growers did not have their ditches clean, and the water in them was low, so that there was great delay m reflowing; and, as a consequence, considerable damage was done bv the frost, 13 DIAGRAM OF THE APPLETON CRANBERRY MARSH SHOWING LOCATION OF CULTIVATED SECTIONS, THE UPLANDS, INSTRUMENT STATIONS, RESERVOIRS, ETC. MATHER, WIS. 9 y -^ arrows show direction of flow of drainage contour lines are given for elevations above: the marsh at station 3. a a trees and brush ISLAND,; \ V ^ A >^ -Vi^ A. A *. ^ hi^'^^-\i X, '^-^:C» a A '> * " ^ >» A A ^ A A ^T^--*Ji ^ '• ■^ ■'^ . A /-^ ■^AAAA '^A^^'^^'\\A'>A-llA A '^.A A /^ /* . . ". "_ A'^~>^Sti.-ja_ A "aaAA^I "A^.^AAAAAAAAA \ A%'^^^a/^aV' I ">!;;a„':;/:..;^/>-.' .\ A. A A A '*■ '^ A aa'''iJ'\^^^''aAA A A Aa A A A ^SLi^ Ay^A^^rt A AAA1 '>A A ro' V^-* A^ A^'z-^v V V A ;»rr#^ A A ; aa ; "'-^-v..aV'^:'^^Va:a''a'^ -^b'^ Fi(i. 3.— Diagram of the Appleton cranberry uiarsh, Mather, Wis. 14 TJiis freeze of August 8 is remembered as more severe than any previous one in n^simimer within the recollection of the Wisconsin cranberry growers. The ilay before, August 7, was cloudy, owin^ to a slight disturbance which was centered over Lake Michigan. The sun's rays were obstructed by dense clouds which kept the temperature of the air in the shade ilowu to a maximum of 65° to 70°. The clouds, however, cleared away just at sunset and the wind, which was fresh during the day. became light in the evening, and the barometer rose steadilv. Thermometers exposed in the vines in peat bogs at Mather and Cranmoor, Wis., recorded minimum readings of 29° and 26"^, respectively, on the morning of August 8, and frosts were severe generally throughout the moorlands. No fi-ost was reported that morning from any of the regular Weather Bureau stations, except Escanaba and Houghton. The minimum temperature at La Crosse, Wis., was 48°; Green Bay, Wis., 45°; Duluth, Minn., 50°; and St. Paul, Minn., 48° — all being readings from instruments located in shelters on the roofs of Fig 4.— Daily weather map. S a. m., August 7. 1904, buildings. It would seem as if only an ext raordinary condition could produce such low tempera- tures in midsummer. A special study shoidd be made of liio weather ma])s of August 7-8 (Figs. 4, 5), showing the general weather conditions prevailing throughout the entire country. On August 7 the slight disturbance, marked "low,'' was central over Lake Michigan, while an area of high barometer, inclosed by the isobar of 30.2 inches, covered the Dakotas. The temperatures in North Dakota were in the forties, and the lowest reading was 40° at Minnedosa, Manitoba. The "low" remained nearly stationary dm'ing the greater portion of the day, causing the cloudi- ness and the relatively low day temperatures in Wisconsin, above referred to. It advanced east- ward, however, by evening. On the morning of August 8 the high was directly over Wisconsin, with the center still inclosed b}^ the .30.2-incli isobar. As a general principle, it may ho stated that the most favoral)le conditions as regards thc^ production of low temperatures locally in the damp lowlands are an overcast sky during the 15 daytime, so that tlie soil is not heated by insolation; clearing at sunset, so that there may be active radiation at night; a rising anil a comparatively high barometer which permits a settling of the cold air toward the ground; a fresh wind in the daytime, which reduces the temperature of the surface of the soil by the cold of evaporation, and which dies down at sunset and conse- cjuently does not interfere with the gradual settling of the cold air to the ground ; and compara- tively low humidity, as radiation from the grounil through dry air is freer, or, in other words, the lower the humidity the less the absorption of heat by the air. On August 7-8, 1904, all the conditions were apparently present for the production of abnormally low minimtmi tempera- ture, viz: Cloudiness and fresh breeze during the day, followed by clearing in evening, rising barometer, falling of the wind, and comparatively low humidit}'. Beginning of the investigation. — As stated above, it was found that but few of the Wisconsin growers had kept any record of temperature and frost contlitions in the bogs. Visits were Fig. 5.— Daily iveather map, 8 a.m.. August 8, 1904. made to several of the marshes ami communication was had with many of the growers for the purpose of securing any available data in anticipation of the proposed investigation. These men are usually intelligent and keen, and intensely interested hi their work, and consecjuently it is strange that so little attention had been given to the preservation of temperature records, as definite knowledge of the subject of temperature in the bogs should be of permanent value. Moreover, there had been a wide divergence of opinion among the growers regarding the problem which was being undertaken, l)ut all seemed to be interested and willing to cooperate. The growers stated that occasionally frost attacked one section of a marsh and left the remainder untouched, without apparent cause; also, that damage was sometimes done to one marsh while another adjoining escaped injury. They were naturally puzzled over these unusual features. In the investigation which Prof. A. R. Wliitson'^ had started at the Cranmoor Experi- ment Station in 1904, the observations were restricted almost entirely to artificial conditions « Wisconsin Bulletin 119, A Report on Cranberry Investigation. 519.;6°— Bull. T— 1) ■! 16 created for the purpose. The section at the Brancli Experiment Station phinted witli cran- berries is not representative of the Wisconsin cranl)erry marshes in actual operation, hut rather of the conditions prevailing on Cape Cod. The plat of tjround at Cranmoor is so small that the various thermometers used in TVIiitson's investigation were comparatively close together, and all were affected more or less by tiie same conditions. Whitson apparently lost sight of tiie fact that a thermometer exposed at any point is largely affected by its environment, as well as by the conditions at the immediate i>oint of exposure. While "WHiitson has endeavored to leail tlie way, anil to induce Wisconsin growers to adopt eastern methods of sanding, cultivating, and draining, the latter have been very slow to follow. For certain reasons that will develop later tlie majority of the AVisconsin growers have not considered it advisable to follow the Massachusetts method in sanding and cultivating. It was deemed best to conduct the investigation by the W^eather Bureau as far as practicable in typical bogs, fidly representing the various conditions existing. In beginning tliis work in June, 1 906, special cranberry marsh stations were established at Cranmoor, blather, Berlin, and Cameron and continued tliroughout the season. The Cranmoor station was at the Wisconsin Branch Fig. 6.— Fitch cranberry marsh, Berlin. Wis., hjoking north along county line ditch where Stations 2. 3, and 4 are located. Fog in the distance on north side of the marsh just after daybreak. Experiment Station in charge of Professor 'Wliitson, referred to al)Ove. It is situated in the center of the Cranmoor region, and adjoins the well-known Gaynor-Blackstone marsh. Tht^ Appleton marsh at Mather was selected because it is typical of the Mather district. (Figs. 2, 3.) Both Cranmoor and Mather are located in the extensive moorlands of the Wisconsin River vallev. The Berlin station, established at the Fitch marsh, is S miles northeast of the city of Berlin in the Fox River valley, and in a much less extensive moorland. (Fig. 6.) The Fitch marsh is old and fairly productive, but poorly drained and lacking in satisfactory means for reflowing. The Cameron station was situated in the northwestern part of tiie State, and the marsh at that point was selected on account of its geographical location and because it was in a narrow gully between stretches of hard land. At these four stations special local observers were secured. Wliile at Cranmoor, the observer was Mr. O. G. Malde, an assistant to Pro- fessor Whitson of the Experiment Station, at the remaining stations the persons employed were managers of the respective marshes. All of the local observers except the one at Cameron -had long experience in making observations. In July, 1906, moreover, an experienced observer was sent from the Ciiicago office to Mather to conduct observations in detail, and the writer 17 himself spent the greater portion of the season in personal work at Mather and Berlin in order to secure the data first-hand. An extensive equipment was secured for the Mather and the Berlin stations for the purpose of goinc; into the subject exliaustively. and thus fuidinci; the true reasons for the comparatively low temperatures in the bogs and their great variation. It was expected that the work in 1906 would be merely preliminary and tliat no definite results could be secured in so brief a period; that only sufficient data could be obtained in the first season to prepare more definitely for the work of 1907. This j)roved to be true, as considerable experimenting was required to determine how and where the various instruments should be exposed. ^Moreover, the soil thermographs, ordered from abroad the previous winter for this special work, did not arrive in this countrv until almost the end of the season, and the results obtained from some of them for tlie month of September, while they were in operation, are of little value. It was extremely difficult to adjust them so as to secure accurate records. Furthermore, the observations made at Cameron were found to be unreliable, and they have not been used in this discussion. The result of the experience with the Cameron observer suggests that observations for scientific purposes should never be intrusted to an untrained observer, even though he receive compensation. The data must be accurate; otherwise the deductions and conclusions have little value. The observa- tions appearing in tliis bulletin, with the single exception of Table 12, were made by regular employees of the Cliicago Weather Bureau office. The stations at BerUn and Cameron were closed at tlie end of the season of 190(). In 1907 the cooperation of the Cranmoor Experiment Station was continued and the work at Mather was much enlarged, trained observers from the Chicago office conducting the observations there from early in May until the end of October. Also during the seasons of 1908 and 1909 a limited number of observations were secured from Cranmoor and Mather. Moreover, observations made at these two stations, beginning with 1905, have been telegraphed daily to the forecast center at Cliicago for the use of the forecaster in i.ssuing frost warnings for the Wisconsin cran- berry marshes. The Berlin marsh liad no facilities for telegraphing and its report was not transmitted daily. Characteristics of stations at Cranmoor, Berlin, and Mather. — The three marshes selected for the investigation are wideh' separated and fairly representative of the conditions prevailing in Wisconsin marshes. Owing to the high state of cultivation at the Cranmoor Experiment Station there is usually no need for reflowing during the entire cranberry season in ors,'raiih made in 1906. Shelter lowered from an elevation of s feet to .5 feet in l'.>07. I-tain gages about 20 feet to tlu- right. They do not niipenr in the picture. Garden in the baeksfround where Station No. 9 was located. from 10 to 25 feet in depth, and the soil of the surrounding islands is a sandv loam, luostlv covered with grass, with brush and trees at intervals. Equipment of the Mather Station. — The instruments at Mather were located at stations widely separated and in the midst of large sections as far as possible typical of the conditions prevailing at the points where the instruments were exposed. An exception was made in fliis respect at Station 7. The following was the equioment in operation in 1907: Station 1, north of the dwelling house on Long Island. The shelter (shown in the ])hoto- graph. Fig. 7, taken in 1906) was lowered in 1907, so that the floor was al)0ut 5 feet above the ground, instead of 8 feet as in 1906. Equipment: Maximum, minimum, and exposed thermometers, also air thermograph, all in the shelter. Station 1 was also ]n-ovided with an Assman aspiration psychrometer, attached to the northeast corner of the dwelling, and two rain gages. A barograph was kept in the dwelling. Station 2 (Fig. S), in the bog over a dense growth of sphagnum mess, outside of the cranberry marsh proper. The moss probably reached to a depth of 6 feet, and, like a s])onge, was saturated with water. The station had. liowever, tlie advantage of being outside the 19 Fig. 8.— Station •_'. Matlier. Wis. In bcig over sphagnum moss and long grass outside cranberry marsh. Photograph made in I'JOe. Thermometers at various elevations up to 36 inehe.s attached to post.s in 1907. Fig. 9.— .Statinn 3. JIather. Wis. Newly sanded, thinly vined. Photograph made in 1907. Grasses seen in the photograph were not present in 1901'., and the vines were not so dense. 20 cultivated sections that were flooded in anticipation of frost, and consequently the c^jjditions as regards moisture varied less here than elsewhere in the hog. Equipment: Air thermograph and maximum and minimum thermometers in the shelter ahout 5 inches above the surface of the marsh. Outside and immediately to the north of the shelter were two posts on which were fastened fi maximum and 6 minimum thermometers facing south at the following eleva- tions: Surface, 21 inches, 5 inches, 7 J inches, 12 inches, and 36 inches; also minimum ther- mometers at additional elevations of 10 inches and 15 inches; 2 soil thermometers in the moss at deptlis of 3 inches and 6 inches, respectively; soil thermograpli, the ])ull) of wliich was exposed at a depth of 3 inches in the moss. Station 3 (Fig. 9), in the cultivated section was heavily sanded durmg the winter of 1905-6. It was thinly vined during 190G, and relatively so as compared with tlie other stations in the cranberry marsh in 1907, but the vegetation was then more dense than in the jirevious year. It may be considered as representing the best conditions on the bog as regards sandmg, cultivating, and draining. Equipment: Minimum thermometer in the shelter at an elevation of about 5 inches above the surface of the bog; minimum thermometer in the open at the sur- FIG. 10.— Stution -1, Mather, Wis. Newly sanded, heavily vined. I'hotograph made in 1907. face of the marsh, also at elevations of 5 inches and 36 inches above the marsh; maximum thermometers similarly exposed at the surface and at 36 inches above the marsh, the thermome- ters at 5 inches and at 36 inches being fastened to a post; air thermograpli which rested on the surface of the soil; soil thermometers at depths of 3 inches and (i indies, respectively: soil thermographs, the bulbs of which were similarly exposed. Station 4 (Fig. 10), also a heavily sanded section, but the vines and vegetation relatively dense. This exposure may be considered as representing the best conditions prevaihng on the bog as reo;ards sandmg and draining. Efpiipment: Minimum thermometer in shelter at an elevation of about 5 inches above the surface of the bog; minimum thermometers in open, at the surface of the bog, and at an elevation of 5 inches; maximum thermometer at the surface of the marsh; an Assman aspiration psychrometer fastened to the shelter; soil thermometers at depths of 3 and 6 inches; soil thermograph, the bulb of wliich was placed in the soil at a depth of 3 inches; anemometer fastened to the top of shelter and attached to a single register inside, the cups of the anemometer being 4 feet 7 inches above the ground. Station 5 (Fig. 11), in an uncultivated portion of the bog, but close to the cultivated sec- tions. It had never been sanded, the soil being plain peat, and it had a dense growth of vines 21 Fm. U.— stiUiouo. JIiitlKT. Wi.v In uneiiltivated bog. Photograpli uiadi; in PJUil. Fig. 12.— Station 6, Mather, Wis. Old sandeil, heavily vined. Photograpli made in 190G. 22 and other vegetation, including numerous patches of sphagnum and wood moss. This location represents the poorest conditions on the cranberry marsh as regards cultivation and drainage, and it was consecjuently wetter than Stations 3 and 4. Equipment: Minimum thermometer in shelter at an elevation of about 5 inelies above the surface of the marsh; minimum thermom- eters in tlio open at the surface of tjie bog, and at an elevation of 5 inches; maximum thermom- eter at the surface of the bog; air thermograph placed in the open on the surface of the marsh; soil thermometers exposed at depths of 3 inches and 6 inches; soil thermographs, the bulbs of which were similarly exposed. During the season of 1907, the vines surrounding the soil instruments dietl out, and gradually changed from tlie conditions prevailing in 1906. This was clue to unavoidable trampling of the vines by the assistant who made the observations. With the purpose of maintaining the original conditions as far as possible, the exposures of these instruments were changed twice during August. Station 6 (Fig. 12), in a cultivated section which had been sanded about ISfls;, l)ut wliich had never been sanded a second time; so that a layer of peat an inch or two in thickness, formed from the decayed vegetation, covered the old sand. There was a dense growth of Fig. 13. — Stations 7 and 7a. Matlier. Wis. In scalped section and on moss adjoining. Photograph made in 1906. vines around the station and the drainage was similar to that of Statitm 5. Equipment: Minimum tliermometer in the shelter about 5 inches above the surface of the marsh; minimum thermometers in the open at the surface of the marsh, and at an elevation of 5 inches; maximum thermometer at the surface of the bog; soil thermometers at depths of 3 and 6 inches; soil thermograph, the bulb of which was exposed at a depth of 3 inches. The soil thermograph was fairly satisfactory for all months except October, when it became defective. Station 7 (Fig. 13), located outside the cultivated bog in a section of bare peat, scalped especially for the purpose in 1906, in the midst of a dense growth of sphagnum moss. This station was at the lower end of 1«he marsh, and consecjuently more damp than the cultivated sections. Equipment: Minimum thermometer in the shelter about 5 inches above the surface of the bog; minimum thermometers in the open at the surface of the peat, and at an elevation of 5 inches; maximum thermometer at the surftice of the peat; soil thermometers at depths of 3 inches and 6 inches; soil thermograph, the bulb of wliich was exposed at a depth of 3 inches. Station 8 (Fig. 14), the reservoir. This station was in a ditch about 4 feet in depth, and from 20 to 25 feet wide, lying between the floating marsh on the west antl a dam on the east. Equipment: Water thermometer; soil tliermograph, with the bulb exposed in the water at a 23 Fig. 14.— Station 8, Mather. Wi.s. Reservoir .allowing; widr- flitch anri filiating bog. Observer taking an observation of water temperature. Fig. 16.— Stiition 9. Mather, Wis. In garden on upland. Photograph made in ia06. This station was supplied in 1907 with additional thermometers in instrument shelter and attached to the po.sts up to an elevation of 36 inches. 24 depth of about 12 inches. This instrument although officialh- known as a soil themiograpli might in this case properly be called a water thermograph. Station 9 (Fig. 15), over sandy loam in the garden in the rear of the dwelling on Long Island. It was established for the purpose of making some comparison between the conditions on hard ground and in the adjoining bog. The garden was planted, but well cultivated and dri.ined. Ecjuipment: Minimum thermometer in the shelter about 5 inches ajjove the surface of the soil; 6 minimum and 6 maximum thermometers facing soutli at the following elevations: Sur- face, 2J inches, 5 inches, 7^ inches, 12 inches, and 36 inches, also minimum thermometers at additional elevations of 10 inches and 15 inches; soil thermometers at depths of 3 and 6 inches. Station 10 (Fig. 16), tlie warehouse. Ecjuipment: Anemometer and sunshine recorder exposed on the cupola of the warehouse, about 50 feet above the marsh, and about 35 feet above the ground on the upland. These instruments were attached to a doid^le register in a room in the warehouse. The wind vane was exposed on a building near the warehouse. Equipment of the Berlin Station. — It is hardly necessary to go into details regarding the erpiipment at Berlin (Fig. 6). The investigation there was confined to a portion of the year Fm. 16. — Station 10, Warehouse, Mather, Wis. Anemometer on enjtola. Sunsliine reeorder on ridjre of roof. 1906, with a rather incomplete set of instruments. The peat and muck in this marsh reaches to a depth of 20 to 26 feet, and there is a stretch of hard land on the immediate border about 3 feet above the surface of the marsh. The soil of this hard land consists of yellow clay. A short distance beyond there is a gradual slope to ordinary dark soil. A portion of the equipment used in this discu.ssion follows. Station 1, which was almost on tlie edge of the bog, was provided with an instrument shelter in which were exposed maximum ami minimum thermometers and an air thermograph. There was also a rain gage close at hand. (Fig. 17.) Station 2, over a peat bog which had been carefully weeded before the observations were begun. Ecpiipment : Minimum thermometers exposed in the open at the surface aiul at an elevation of 5 and 36 inches, respectively, above the surface of the marsh. The sections around Stations 3 and 4, to an extent of about 40 feet scjuare, had been espe- cially sanded for use in the investigation. The marsh, as a whole, had a rank growth of vege- tation, and had never been sanded. At Station 3 were minimum thermometers exposed in the open at the surface and at 5 and 36 inches above the surface; also a soil thermometer at a 25 Fig. 17.— Fituh marsh, Berlin. \Vi^., showing oar track on bog, dwellings, warehouses, and shanties. Cross in iiliotograph shows location of Station 1 in I'Wii. Fig. IS.— Station 5, Fitch marsh, Berlin, Wis. In ferns and canebrakes. 26 depth of 3 inches. This station well represents the best conditions obtainable from oultivating and sanchng, and fair conditions as regards draining. Station 4 had the same character, except that it was slightly lower than Station 3, and consecjuentl}- wetter through poorer drainage. The equipment consisted of minimum thermometers exposed in the open at the surface and -5 inches above. Stations 2, 3, and 4 were situated in a line about 100 feet apart. The thermometer shelters at Stations 2 and 3 ma}' be seen in Figure 6, which gives a view of a considerable portion of the Berlin marsh at da\\-n. Xo shelter was used at Station 4. The shelters at the other stations on the bog were used for housing the recording portions of the soil thermographs iluring the short time that they were in operation. These instruments proved defective in 1906, and consequently the records have not been used. Station .5 (Fig. IS), in a section termed the "ferns," about 1,000 feet north of Stations 2, 3, and 4. The equipment consisted of maximum and minimum thermometers placed at the surface of the bog and at an elevation of 5 inches, respectively. The upper thermometers here were not fastened to a post, but merely placed on top of a bed of vines and ferns, which were pushed down in a compact mass to provide a resting place for the instruments at the desired height. In all other instances at Mather and Berlin the instruments exposed at an elevation above the surface were attached to wooden supports. Station .5 was also provided with a soil thermometer at a depth of 3 inches. Some additional instruments were included in the equip- ment, at the various stations, but it seems imnecessary to refer to them. The object has been to present in this report merely such observations made at Berlin as niav supplement the more complete data at Mather. The thermometers used in this investigation were all carefully tested in the Instrument Division at Wa.shington before being shipped to the cranberry marshes: they were daily exam- ined in order to detect possible defects, and exchanges in the instruments were made occa- sionally between the various stations at both Mather and Berlin, so as to obviate the effect of any possible instrumental error. DISCUSSION OF THE PROBLEM. Minimum temperatures in shelters, and in the open, both at 5 inches above the surface. — In order to dete^-mine the relation existing between the readings of thermometers in shelters and those exposed in "the open," as are the instruments generally used by the cranberry grower, minimum thermometers were placed at various stations at blather, in "the open" at 5 inches above the surface, corresponding in elevation to the thermometers placed in the respective shelters. During the day the svirface of any solid upon which the sun shines becomes hotter than the air above it, because the solid is a much better absorber of heat than the air; while at night, especially when the sky is clear, the air loses its heat more slowly than a solid, such as vegetation or soil, because the air is a very poor radiator of heat. The readings of the instru- ments in the shelters indicate the true temperature of the air at the various stations, while the readings of the thermometers outside the shelters, strictly .speaking, represent the temperatures of the instruments themselves, but they may be considered to indicate approximately the tem- perature of the vines and plants at the height of 5 inches. It is probable that the temperature of the vegetation was even lower than that recorded b}- these exposed minimum thermometers. The differences, however, can not be large, because the exposed minimums often registered readings as low as 28° without apparent damage to the vegetation. It is quite impracticable to secure daily readings of the temperature of plants or leaves that may be comparable. The reading of the thermometers exposed in the open might properly be termed "sensible tempera- tures," but in this bulletin all such readings, whether maximmn or minimum, will be referred to as exposed readings, or readings in the open. Table 1 shows in detail the daily readmgs and differences at each station, and Table la shows the averages for the various months and for the season of 1907. The average difference for the entire season was least at Station 9 on the upland, 1.4°, where there was a clean soil and very little vegetation. The average difference on the bog was least at Station 3, 2.5°, also where •27 the vegetation was thin; and at Station 7, 2.7°, over peat, in the scalped piece, but closely surrounded by sphagnum moss. The difference was greatest at Station 5, 3.6°, and at Station 6, 3.7°, where the vegetation was dense. The average difference at Station 4 was 2.6° — but slightly greater than that at Station 3. This difference was not larger because the location of the thermometers exposed at the 5-iuch height at Station 4 was tliinly vined as compared with the other portions of that section. In fact, a close relation was founfl to exist between these differences and the density of vegetation. On account of the great radiation of heat from vegetation, the exposed minimums were relatively much lower where the vegetation was dense than where the soil was clean. At all stations the least difference usually occurred during the month of May, with an increase irregularly toward midsummer with increasing vegetation, and then a falling off, which was later followed by another maximum in October. The gains and losses were not uniform at the various stations, simply because there was a lack in uniformity in the changing of the vegetation. The conditions changed because there was trampling of the vines and grasses, more at some stations than at others, and for various other reasons. It is probable that if all the conditions as regards vegetation, soil, and moisture were identical for the whole bog, or even for the section in which the instruments were located, approximately the same differences would occur at each station on each night : Init the amounts of these differ- ences would probably change as the nights became longer or shorter, and as the character of the weather varied from day to day. iloreover, if a uniform relation existed during the entire season as regards vegetation, between the places of exposure of the outside thermometers and the location of the shelter itself, the relation between the various differences of the readings o inside and outside would not change materially. The reason for the great differences in October is not because of increasing vegetation, but rather in spite of a decrease. It is due to the fact that the nights were much longer and com- paratively cokl, thus permitting great loss of heat from the plants by radiation and conduction. The greatest difference at Station 2 was 6.5° on October 11 ; at Station 3, 4.7° on October 31 ; at Station 4, 6.3° on October 22; at Station 5, 9.9° on July 10; at Station 6,7.9° on July 16: at Station 7, 6.4° on May 18; and at Station 9, 7.2° on August 10. There were, on the other hand, many days when there was only a slight difference in the readings, and there were a few instances in wliich the outside thermometers read slightly higher than those exposed in the shelters. Wlien the difference was great at one station, it was usually relative^ great at the other stations: likewise, when there was but a slight difference at one point, a like condition prevailed at the other stations. On nights of slight differences the sky was invariably overcast, while clear to partly cloudy conditions with comparatively lugh barometer prevaUed when great tlifferences occurred, which fact indicates that radiation is the controlling factor. Formation of dew on the bulbs of the outside thermometers, followed by a freshening of the wind and consequent evaporation of the moisture, was occasionally the cause of low readings of certain of these instruments. Dew doubtless often formed and disappeared during the night without being observed. The mean depression of the outside thermometers below those in the shelters at the six stations on the bog for the entu-e season of 1907 was 3°, and, including the record at Station 9 on the upUnd, the depression for the same period was 2.8°. Prof. WiUis I. Milham, « in experiments conducted at WUliamstown, Mass., on thirty-sLx cold and generally cloudless nights in the winter of 1904-5, wliile the ground was covered with snow, found that the average difference between the readings of a minimum thermometer expo.sed in a shelter and one in the open was 3.9°, and that the greatest difference on any one night was 7.8°. In making comparisons between these figures and the results at Mather over vegetation, it should be borne in mind that the latter are for the entire growing season without regard to the cloudiness and the tem- perature prevailmg. The average difference on dear nights at Mather no doubt equals that determined by Professor ^lilham. a Monthly Weather Review, July, 1905. 28 The temperature in the shelter on the upland at Station Imay be considered theWandard with which other temperatures observed at Mather during this investigation should be compared. However, the readings at Station 1 have not been included in Tables 1 and la, because it was first desired to determine the relation existing between shelter and exposed temperatm-es at the same elevation, ^j referring to Table 18, which will be discussed in detail in turn, it should be noted that there is a great difference between the shelter readings on the bog and on the upland, the difference varying with the character of the soil and vegetation, as in the case of the observa- tions in shelter and in open at the various stations, referred to above in connection with the discussion of Tables 1 and la. Where the differences were great between the readings in shelter and open, relatively large differences were noted between the readings in those shelters and the shelter at Station 1 ; while, on the other hand, at stations where smaller differences were observed, the shelter readings approached more nearly the shelter readings at Station 1. Table 1. — Minimum Temper.^tures in Shelter and i.n open .\t 5-inch Height, for Each Station, Together WITH the Difference between Readings, Mather, .Wis., 1907. Station 2. Station 3. Station 4. Station 5. Station 0. Station 7. Station 9. Day of montb. in I 1 i •d X a T3 X I 5 to ■d o, X 1 5 a) •6 X 1 1 1 i 5 1 « 5 MAY. 1 o e o e a " » • . : . • ~ a ' • B o e « . ' . ' . 2 1 3 1 4 6 1 8 9 1. 10 11 .. . 1 12, 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 36.7 ei.o 45.0 36.0 34.8 35.0 35 3 33.0 gl.i 23.2 43.8 43.8 42.5 44.8 45.0 (') 34.0 38.9 46.5 35.2 60.0 45.0 36.3 34.1 32.4 32.0 28.2 18.0 21 44.0 43 9 40.2 44.0 45.2 C) C) 29.8 36.0 45.0 -1.5 -1.0 0.0 +0.S -0.7 -2 6 -3.3 -IS -3.4 -2.2 +0.2 +0.1 -2.3 -0.8 +0.2 -4.2 -2.9 -1.5 37.3 ei.6 45.7 37.0 35.4 40.3 45.4 36.8 25. S 25.7 44.3 44.3 43.8 45.3 45.5 C) C) 38.0 44.7 48.0 35.4 59.6 45.0 36.7 34.6 38.4 40.9 32.6 Sl.S 22.8 44.0 43.9 41.3 44.0 45.2 34.9 41.1 45.8 -1.9 -2.0 -0.7 -O.S -0.8 -1.9 -i.5 -4.2 -4.0 -2.9 -O.S -0.4 -2.5 -1.3 -O.S -3.1 -3.6 -2.2 37.4 en 45.8 37.0 35.5 40.3 45.1 36.3 U.l 2b. i 44.5 44.2 43.5 45.2 45.7 C) W 37.2 43.8 47.8 35.4 59.0 45.1 37.0 34.6 37.3 39.0 32.0 20.0 22.3 44.2 44.0 42.0 44.1 45.2 C) 32.5 39.5 45.9 -2.0 -2.4 -0.7 0.0 -0.9 -3.0 -6.; -4.3 -5.1 -3.1 -0.3 -0.2 -1.5 -1.1 -0.5 -4.7 -4.3 -1.9 37.0 «/.« 45.1 36.7 35.3 36.0 40.1 36.6 21.6 22.2 44.5 44.0 40.3 45.0 45.2 (') C) 36.0 40.4 47.6 35.0 58.9 45.1 36.9 34.8 33.0 39.1 31.0 19.3 17.0 42.0 43.7 34.0 43.8 45.0 m C) 29.3 36.0 45.9 -2.0 -2.3 0.0 +0.S -0.5 -3.0 -1.0 -5.6 -2.3 -5.2 -2.5 -0.3 -6.3 -1.2 -0.2 -6.7 -4.4 -1.7 37.0 60.9 45.0 36.8 35.0 32.5 41.2 3S.6 24.8 Si. 5 44.1 44.1 43.3 45.0 45.2 ('') m 38.5 43.0 47.9 34.2 57.2 44.9 37.0 34.2 33.0 39.3 32.3 17.8 19.8 43.0 44.0 39.3 43.9 45.0 m C) 34.7 39.0 45.4 -2.8 -3.7 -0.1 +0.2 -0.8 +0.5 -1.9 -6.3 -7.0 -4.7 -1.1 -0.1 -4.0 -1.1 -0.2 -3.8 -4.0 -2.5 36.7 61.0 45.0 36.8 35.1 35.4 39.8 37.8 21. S 23.7 44.0 044.2 "42.9 044.9 045.2 (») m 36.0 40.9 047.2 35.1 58.0 44.9 36.7 34.3 32.3 33.4 32.1 18.9 22.0 43.9 043.9 O40.0 O44.0 045. C) m 30.8 37.0 045.4 -1.6 -3.0 -0.1 -0.1 -0.8 -3.1 -e.i -5.7 -2.4 -1.7 -0.1 -0.3 -2.9 -0.9 -0.2 -5.2 -3.9 -1.8 37.4 61.5 45.0 36.0 35.0 39.9 46.0 37.3 26.8 25. S 44.1 44.0 43.4 44.6 45.1 (0) C) 38.8 44.0 47.6 36.7 59.8 45.0 36.0 34.8 39.1 44.9 35.0 23.8 2S.0 44.2 44.0 41.8 44.0 45.1 C) m 36.3 42.3 46.8 -0.7 -1.7 0.0 0.0 -0.2 -0.8 -1.1 -2.3 -3.0 -2.3 +0.1 0.0 -1.8 -0.6 0.0 -2.5 -1.7 -0.8 Means . 38.9 37.2 -1.7 1 41.4 39.3 -2.1 1 41.2 38.8 -2.4 39.7 37.2 -2.5 40.4 38.0 -2.4 39.9 37.6 -2.3 41.2 1 40.1 -1.1 a Affected by water. Station 2. Sphagnum moss. Station 3. Newly sanded, thinly vined. Station 4. Newly sanded, heavily vined. Station 5. Feat with raoss, heavily vined. 6 Under water. Station fi. Old sanded, heavily vined. Station 7. Scalped piece, bare peat. Station 9. Sandy loam on upland. Highest and lowest readings are in italics. Means are for 18 days. 29 Table 1. Minimlm Temperatures w Shelter and in Open at 5-inch Height, for Each Station, Together WITH THE Difference between Readings, Mather, Wis., 1907— Continued. Day of month. 7 8 9 10 11 12 13 1-1 15 16 17 18 19 211 21 22 23 24 23 2B 27 28 29 30 Means . 45. 4 31.7 32.3 54.0 38.4 41.8 31.4 47.0 31.4 35.9 53.9 44.1 51.2 37.3 35.0 38.7 48.6 ee.o 52.5 50.2 45.2 45.0 61.2 68.0 53.9 55.9 46.0 39.3 41.2 44.8 51.3 17.9 29.4 53.0 35.2 38.0 17.9 44.8 g7.9 32.5 63.3 39.1 50.6 34.4 31.0 35.0 46.0 6$. 9 49.6 46.8 42.3 41.4 59.0 53.9 49.6 53.3 40.9 35.2 36.7 42.6 48.9 -3.8 -2.9 -1.0 -3.2 -3.8 Station 3. 34.9 37.0 54.9 42.7 43.9 -3.6 034.0 -2.2 47.9 -3.5 -3.4 -0.6 -6.0 -0.7 -2.9 -4.0 -3.7 -2.6 -3.1 -2.9 -3.4 -2.9 -3.6 -2.2 -4.1 -4.3 -2.6 -S.l -4.1 -4.5 -2.2 ■2.4 35.0 40.0 54.6 46.2 63.0 42.6 39.9 42.0 54.0 69.0 68.0 56.2 51.0 49.3 61.8 60.0 56.0 57.9 48.1 44.6 44.3 51.4 56.9 42.3 -3.1 -48.9 31.0 34.0 52.3 39.6 39.7 ■■31.3 47.5 32.2 37.4 53.2 42.2 51.0 39.6 37.9 39.3 61.2 65.8 55.2 53.3 48.0 46.5 60.4 67.7 53.8 66.3 46.1 42.0 41.1 48.9 54.1 3.9 3.0 2.6 3.1 4-S 2.7 0.4 2.8 -2.6 -1.4 -4.0 —2.0 -3.0 -2.0 -2.7 -2.8 -3.2 -2.8 -2.9 -3.0 -2.8 -1.4 -2.3 -2.2 -1.6 -2.0 -2.5 -3.2 -2.5 -2.8 Station 4. 34.9 36.1 54.8 41.8 43.5 aSS.4 47.7 35.1 39.9 54.6 45.5 52.9 42.3 39.4 41.4 52.9 69.1 56.9 55.8 49.8 48.8 61.5 69.9 55.2 57.4 47.9 43.4 43.8 50.0 65.5 48.4 SO.S 33.0 51.0 39.0 41.4 "SO. 7 46.0 32.0 36.2 53.2 41.7 52.1 39.1 36.3 39.0 50.2 65.4 64.9 52.5 47.5 46.1 60.1 57.1 53.0 56.9 46.0 40.9 41.0 48.0 53.0 -4.4 -3.1 -3.8 -2.8 -2.1 -2.7 -1.7 -3.1 -47 -1.4 -3.8 -0.8 -3.2 -3.1 -2.4 -2.7 -3.7 •2.0 -3.3 ■2.3 ■2.7 1.4 ■2.8 2.2 1.6 1.9 2.5 2.8 2.0 2.5 Station I 45.7 :-2.7 44.6 51.0 41.1 47.4 1 •a p, K o „ 31.4 26.2 31.4 27.9 63.6 46.9 40.2 36.0 43.3 41.5 <'30.7 026.8 47.0 43.8 30.8 26.5 35.1 30.6 54.0 53.0 44.2 38.4 62.5 61.0 36.2 32.4 33.8 29.6 37.6 34.0 48.9 45.5 ■ 68.5 61.5 52.7 48.9 ■ 53.4 48.7 - 61.0 42.4 - 44.0 40.3 - 61.1 59.6 - 59.0 56.2 - 62.5 49.5 - 56.9 53.1 - 47.8 45.7 - 39.2 34.0 - 38.6 35.2 - 6.2 3.5 6.7 5.2 -1.8 3.9 3.2 -4.3 -4.6 -l.O -5.8 -1.6 -3.8 ■4.2 ■3.6 ■3.4 ■6.0 -3.8 ■4.7 ■*.« ■3.7 ■1.5 ■3.8 3.0 2.8 2.1 5.2 3.4 3.5 3.6 Station 6. -3.9 36.0 35.0 63.6 40.3 44.0 aSS.O 47.7 34.3 38.3 54.3 45.2 62.3 39.4 33.0 39.5 60.4 68.0 55.0 63.4 47.8 46.8 61.1 60.0 53.9 56.2 48.3 40.8 40.5 47.8 54.2 35.3 29.8 47.0 36.5 41.5 ai8.2 44.0 29.4 33.9 52.9 40.7 50.2 34.8 33.0 36.1 46.8 64.0 50.6 47.5 43.4 42.4 59.1 56.3 50.8 53.2 43.8 35.1 37.5 42.8 48.7 -0.7 5.2 -6.5 -3.8 -2.5 -3.8 -3.7 -4.9 -4.4 -1.4 -4.5 -2.1 -4.6 0.0 -3.4 -3.6 -4.0 -4.4 -6.9 -4.4 -4.4 -2.0 -3.7 -3.1 -3.0 -4.5 -5.7 -3.0 -5.0 -5.5 Station 7. -3.8 34.5 34.8 53.5 40.3 43.3 31.1 47.5 31.4 36.0 63.9 44.8 53.0 37.3 34.6 38.0 49.5 69.0 65.0 54.0 46.0 { 45.0 61.1 59.2 63.4 66.2 48.0 38.2 39.8 46.1 53.1 46.3 28.7 30.7 50.0 36.6 41.5 S7.t 45.1 27.9 32.0 53.0 40.1 61.4 33.6 31.1 34.8 46.6 65.9 51.0 49.3 42.2 41.8 59.8 56 49.6 53.5 46.0 35.0 36.8 43.0 49.4 -5.8 -4.1 -3.5 -3.7 -1.8 -4.0 -2.4 -3.6 -4.0 -0.9 -4.7 -1.6 -3.7 -3.5 -3.2 -2.9 -3.1 -4.0 -4.7 -3.8 -3.2 -1.3 -3.2 -3.8 -2.7 -2.0 -3.2 -3.0 -3.1 -3.7 Station 9. 43.0 -3.3 34.5 36.2 55.1 41.6 43.8 S3.0 47.3 33.5 39.2 54.5 46.0 53.0 42.9 37.5 42.0 53.8 68.0 57.3 66.1 50.1 48.6 61.7 59.8 54.1 57. 5 48.1 44.5 43.9 51.1 56.8 48.4 32.2 32.8 53.8 40.4 42.9 31.5 46.6 31.8 37.9 53.4 43.7 62.5 41.1 36.1 41. a 52.0 66.5 55.7 51.9 47.9 46.6 60.6 57.5 53.2 56.5 47.2 42.8 42.1 49.8 54.1 46. S Station 2. .Sphagnum moss. Station 3. Newly sanded, thinly vined. Station 4. Newly sanded, heavily vined. Station 5. Peat with moss, heavily vined. " .\fTected by water. Station 0. Old sanded, heavily vined. Station 7. Scalped piece, bare peat. Station 9. Sandy loam on upland. -2.3 -3.4 -1.3 -1.2 -0.9 -1.5 -0.7 -1.7 -1.3 -1.1 -2.3 -0.5 -1.8 -1.6 -1.0 -l.S -1.5 -1.6 -1.2 —2.2 -2.0 -1.1 -2.3 -0.9 -1.0 -0.9 -1.7 -1.8 -1.3 -2.7 -1.6 Highest and lowest readings are in italics. 30 Table 1. — Minimum Temperatires ix Shelter and ix Opex at 5-ixch Height, for Each Station-, Together WITH THE DiFFEREXCE BETWEEN READINGS. Mather. Wis.. 1907 — Continued. * Station 2. ' Station 3. Station 4. Station 3. Station 5. station 1 Station J. Day of month. o OD 1* . g 1 1 i i 1 1 Q 1 m i 5 1 QD ■d X s a S 1 m •d 8 B 2 & a 1 GO i S 1 •d X K i 2 5 1 JULY. = e e o o o e a e , „ « a „ 1 55.0 52.0 -3.0 58.8 57.1 -1.7 58.5 57.0 -l.S 58.8 55.9 -2.9 58.7 54.3 -4.4 59.0 58.1 -0.9 59.0 57.8 -1.2 2 SI. 4 29.4 -3.0 SS.i S4.8 -3.6 S7.4 34. S -3.1 Sl.l tT.9 -3.3 So. I i9.0 -6.2 SS.O 29.7 -3.3 S6.9 SS.9 -s.o 3 41.4 38.5 -2.9 48.0 45.0 -3.0 47.1 44.7 -2.4 40.2 36.2 -4.0 44.1 38.3 -5.8 43.0 39.2 -3.8 47.7 45.0 -2.7 4 47.3 1 44.7 -2.6 51.6 48.9 -2.7 50.8 48.8 -2.0 50.8 43.9 -6.9 49.9 46.0 -3.9 47.4 45.0 -2.4 51.0 49.5 -1.5 5 60.6 59.4 -1.2 61.3 60.3 -1.0 61.2 60.5 -0.7 60.8 59.7 -1.1 61.0 61.5 +0.0 OS7.5 054.7 -2.8 61.0 60.0 -1.0 6 55.0 52.8 -2.2 59.0 57.0 -2.0 58.0 56.2 -1.8 54.8 52.0 -2.8 56.8 52.1 -4.7 "55.5 "52.1 -2.8 58.2 57.3 -0.9 7 46.3 . 43.2 -3.1 1 51.2 48.0 -3.2 50.8 48.0 -2.8 50.8 42.5 -8.3 49.0 43.7 -5.3 48.9 46.3 -2.6 50.4 49.0 -1.4 8 50.0 ! 47.0 -3.0 56.9 53.1 -3.8 55.0 50.4 -4-6 54.3 49.4 -4.9 1 55.8 50.0 -5.8 57.0 53.4 -3.6 58.1 56.2 -1.9 9........ 54.1 j 51.0 -3.1 61.0 57.1 -3.9 i 60.0 56.1 -3.9 56.6 51.9 -4.7 57.5 51.4 -6.1 56.9 52.5 -4.4 60.4 59.9 -0.5 10 45.2 ; 42.3 -2.9 50.8 47.8 -3.0 1 49.8 47.7 -2.1 50.9 41.0 -9.9 47.0 42.2 -4.8 45.9 42.2 -3.7 50.0 47.6 -2.4 11 59.8 1 60.2 +0.4 60.6 60.3 -O.S 60.8 60.0 -0.8 61.1 60.1 -1.0 61.5- 59.9 -1.6 61.0 60.1 -0.9 61.0 60.1 -0.9 12 44.5 42.3 -2.2 49.5 46.5 -3.0 48.4 46.1 -2.3 46.2 39.9 -6.3 46.3 41.8 -4.5 45.0 41.5 -3.5 49 2 47.0 -2.2 13 47.0 44.3 -2.7 53.0 50.0 -3.0 51.6 49.2 -2.4 48.4 44.0 -4.4 51.3 45.9 -5.4 49.9 45.9 -4.0 52.0 49.4 -2.6 14 60.9 56.4 -4.5 62.2 59.0 -3.2 62.0 59.1 -1.9 61.2 56.8 -4.4 61.5 56.8 -4.7 61.3 58.2 -3.1 62.0 60.0 -2.0 15 6S.0 67. S -0.2 6S.S ea.s -0.5 6S.1 67.8 -O.S 68. « 67.1 -1.1 68.0 66.7 -1.3 68.0 68. i +0.« 68.1 68.0 -0.1 16 49.3 46.3 -3.0 53.1 50.0 -3.1 52.2 i 50.0 -2.2 51.1 45.3 -5.8 54.4 46.5 -7.9 48.9 46.1 -2.8 51.7 50.4 -1.3 17 4S.3 45.0 -3.3 55.1 51.3 -3.8 52.1 49.0 -3.1 50.0 45.0 -5.0 53.2 47.3 -5.9 54.0 47.9 -6.1 56.0 53.9 -2.1 18 46.9 44.5 -2.4 51.0 47.6 -3.4 50.1 47.8 -2.3 45.8 42.6 -3.2 47.9 43.8 -4.1 46.0 43.1 -2.9 1 50.2 49.0 -1.2 19 52.8 51.8 -1.0 57.1 54.8 -2.3 56.8 54.8 -2.0 5.3.9 51.0 -2.9 56.0 51.5 -4.5 54.1 51.6 -2.5 I 56.8 55.1 -1.7 20 52.9 50.1 -2.8 59.8 56.7 -3.1 59.0 55.1 -3.9 562 51.3 -4.9 58.0 52.5 —5.5 58.6 56.2 -2.4 1 60.3 58.9 —1.4 21 62.0 j 60.2 -1.8 65.0 63.2 -1.8 64.8 63.0 -1.8 62.2 59.9 -2.3 63.0 60.0 -3.0 62.8 61.1 -1.7 1 64.8 64.0 -0.8 22 60.0 1 57.3 -2.7 63.0 62.0 -1.5 63.2 61.4 -1.8 64.0 61.9 -2.1 ' 54.5 62.3 -2.2 "61.3 "58.5 -2.8 ' 63.9 63.0 -0.9 23 54.0 1 48.9 -S.I 53.2 50.1 -3.1 52.2 48.8 ; -3. 4 050.3 045.9 -4.4 051.0 O40.7 -4.3 050.1 047.3 -2.8 52.1 49.9 —2.2 24 61.0 58.7 -2.3 64.0 60.0 -4.0 64.0 59.8 -4.2 "61.5 "57.1 -4.4 062.2 057.9 -4.3 061.3 058.5 -2.8 ' 65.0 63.1 -1.9 25 52.8 49.5 -3.3 53.7 50.9 i-2.8 53.0 1 50.8 -2.2 ooO.l "45.7 -4.4 "50.8 "46.5 -4.3 "49.9 047.1 -2.8 53.0 51.6 -1.4 26 46.3 42.3 -4.0 49.4 47.0 -2.4 48.5 46.3 -2.2 046.5 042.1 -4.4 047.2 "42.9 -4.3 "46.3 "43.5 -2.8 49.0 47.8 -1.2 27 44.9 41.0 -3.9 46.9 43.4 -3.5 45.9 ' 43.0 -2.9 45.0 40.0 -5.0 043.2 038.9 -4.3 "42.3 "39.5 -2.8 1 44.9 43.4 -l..i 28 56. 6 55. 3 -1.3 58.9 i 57.0 -1.9 59.2 56.5 -2.7 57.5 53.2 -4.3 58.4 54.0 -4.4 056.2 053.4 -2.8 59.0 56.9 -2.1 29 51.3 48.1 —3.2 ; 56.1 54.0 -2.1 55.9 53.2 -2.7 55.0 51.5 —3.5 56.1 53.0 -3.1 56.5 55.0 -1.5 ' 56.1 55.0 -1.1 30 46.5 45.0 -1.5 51.0 48.1 -2.9 49.9 46.4 -3.5 50.0 41.6 -8.4 48.9 43.2 -5.7 49.5 45.9 -3.6 ! 52.0 49.9 -2.1 31 52.9 48.5 -4.4 1 56.1 53.1 -3.0 55.2 52.0 -3.2 54.4 50.0 -4.4 55.0 49.8 1 1 -5.2 55.3 53.0 -2.3 1 57.0 55.7 -1.3 Means.. 51.8 49.2 -2.6 j 55.6 j 53.0 -2.6 54.9 52.4 1-2.5 ! 53.1 48.8 -4.3 ' 53.8 49.6 -4.2 53.0 50.2 -2.8 1 55.4 53.8 -1.6 o Estimated: actnal readings valueless on account of reflowing or heavy rains. Station 2. Spagnum moss. Station 3. Newly sanded, thinly vined. Station A. Newly sanded, heavily vined. Station 5. Peat with moss, heavily vined. Highest and lowest readings are in italics Station 6. Old Sanded, heavily vined. Station?. Scalped piece, bare peat. Station 9. Sandy loam on upland. 31 Table 1— Minimi M Temperati RES IN Shelter ank ix Open" at o-inch Height, for Each Statiox wiTH THE Difference between Readinc.s, Mather, Wis., 1907 — Continued. Together Day of month. Station 2. Station 3. £ ^ AUGUST. ^ o 1 51.7 2 42.8 3 43.1 4 se.B 5 58.9 6 48.1 7 51.3 S ' 53.0 9 52.0 10 67.0 U 7/. 6 12 43.4 13 45.6 14 49.3 15 53.6 16 59.4 17 47.0 18 51.0 19 65.0 20 38.9 21 39.8 •» 37.7 23 51.2 24 44.7 25 38.1 26 46.4 27 55.1 28 54.0 29 47.6 30 63.5 31 54.9 Means. 47.0 39.1 40.0 34.1 37.9 46.0 48.2 51.0 48.9 54.6 70. S 40.1 42.0 46.0 49.6 57.7 43.4 47.7 64.7 34,1 35.7 33.9 47.2 41.0 Sg.7 42.5 56.5 49.9 43.7 62.3 52.4 2.0 56.0 -3. 1 54. 6 -4.7 54.9 -3.7 45.3 -3.1 47.9 -2.1 44.9 -1.0 59.1 -2.1 53.4 -3.1 57.0 2.4 1.1 3.3 3.6 3.3 -4.0 1.7 -3.6 3.3 -0.3 -4.8 -4.1 -3.8 -4.0 -3.7 -5.4 -3.9 -4.1 -3.9 -1.2 -2.5 50.1 47.1 60.1 71.9 50.4 49.8 53.0 56.4 61.7 51.1 55.5 65.0 43.3 49.0 4^.5 51.7 50.9 44.3 50.4 55,8 57.0 51.6 63.8 57.6 51.2 43.3 44.5 42.1 58.3 51.0 54.8 54.0 51.8 58.0 67.4 46.7 46.8 50.6 53.4 60.3 48.6 52.3 65.0 39.8 44,6 S9.S 48.3 47.6 40.8 47.8 55.0 63.4 49.5 63.3 55.8 Station 4. -3.7 -2.0 -3.4 -2.8 -0.8 -2.4 -2.2 -2.0 -2.8 -2.1 -4.S -3.7 -3.0 2.9 -3.0 -1.4 -2.5 3.2 0.0 -3.5 4.4 3.0 3.4 3.3 3.5 2.6 0.8 -3.6 -2.1 -0.5 -1.8 51.2 -2.6 53.4 45.0 47.0 43.2 59.1 52.1 56.4 55.6 54.1 59.5 70.0 48.6 48.9 52.7 56.0 61.5 49.8 54.2 65.0 42.0 47.7 41.4 54.5 50.8 43.4 49.8 55.6 56.0 51.1 64.4 57.6 53.1 49.1 42.5 43.8 39.7 58.2 49.0 54.0 55.3 51.9 57.8 68. S 44,0 45.9 50.0 53.0 60.2 47.6 51.5 64.8 38.5 43.6 SS.4 51.1 46.8 38,7 47.0 55.2 53.5 48,6 63.7 55.4 50.6 •4.3 -2,5 -3.2 -3.5 -0.9 -3.1 -2.4 -0.3 -2.2 -1.7 -1.7 -4.6 -3.0 -2.7 -3.0 -1.3 -2.2 -2.7 -0.2 -3.5 -4.1 -3.0 -3.4 -4.0 Station 5. 51.0 44.3 45.8 S6.9 59,0 47.9 56.1 52.0 51.5 53.8 7/. 5 45.2 44,0 48.3 34.5 61.0 42. S 50.2 64.9 40.6 40.7 37.5 50.1 49.6 —4.7 I 38,2 -2.8 0.4 2.5 -2.5 -0.7 -2.2 -2.5 45.0 55.7 54.4 46.8 63.7 54.9 44.0 40.9 41.9 S3.0 58.0 44.8 54.0 50.1 48.0 53.0 69.0 41.0 40.6 45.0 50.2 58,6 43,6 46.7 64.8 34.8 35.6 33.6 46.1 44.3 33.3 41.0 55.6 50.5 44.0 62.6 52.7 Station 6. -7.0 -3.4 -3.9 -3.9 -1.0 -3.1 -2.1 -1.9 -3.5 -2.8 -2.3 -4.2 -3.4 -3.3 -4.3 -2.4 +0.S -3.5 -0,1 -5.8 -5.1 -3.9 -4.0 -5.3 -4.9 -4.0 -0.1 -3.9 -2.8 -1.1 -2.2 50.3 I 47.1 51.6 44.0 46.0 41,5 39.0 49.9 56.3 55.0 53.4 59.1 70.0 50.0 47.0 50.5 55.5 61.0 49.2 54.1 64.9 41.0 46.8 40.0 51.9 50.8 41.2 47.9 57.5 55.4 49.6 61.8 56.5 43.3 41.5 41.8 36.0 57.3 45.9 53.4 51.1 49.0 -6.1 -2.5 -4.2 -5.5 -1.5 -4.0 -2,9 -3.9 -4.4 .5 -3.6 -3.2 52.1 68. S 43.2 42.0 4C.1 51.1 58.2 44.1 48.7 64.3 36.3 40.4 SS.S 47.3 46.5 33.6 43.8 35.6 51.3 45.3 62.7 53. S -1.5 -6.8 -5.0 -4.4 -4.4 -2.8 -3.1 -5.4 -0.6 -4.7 1-6.4 i-4.7 -4.6 5 1-4.; 48.3 -5.6 -4.1 -1.9 -4.1 -4.3 +0.9 -3.0 51.4 44.8 46.9 S3.0 59.2 48.1 56.1 55.0 51.3 57.0 71. S 48. 44.8 49.1 54.8 61.3 48.7 47.1 43.0 45.0 SS.S 58.0 45.4 34.4 31.5 48.8 54.3 69. « 42.7 41.4 46.1 50.6 59.3 44.3 5 52.0 I 48.9 65.0 65.0 44.8 43.5 41.8 I 38.8 39.0 I 33.6 51.2 48.0 "51.7 42.6 48.4 56.0 36.0 50.1 64.0 "55.7 049.2 38.3 44.8 55.8 52.6 48.6 62.1 33.8 -3.8 ' 51.6 4.3 1.8 1.9 2.2 1.2 2.7 1.7 3.5 2.5 2.7 2.0 5.S 3.4 3.0 4.2 -2,0 -4.4 -3.1 0.0 -1.3 -3.0 -3.4 -3.2 -2.5 -4.3 -3.6 -0.2 -3.4 -1.3 -1.9 -1.9 54.9 45.0 46.8 38.9 59.0 53.5 56.7 55.0 53.4 59.2 73. « 51.0 49.3 52,7 56.1 61.3 51.2 36.0 65.0 42.5 46.5 42.6 53.5 52.5 46.0 50.0 55.2 57.0 51.4 62.3 58.0 52.8 43.9 46.5 37.7 58,2 51.3 55.1 53.6 51.9 32.0 70.9 49,0 47.5 50.4 54.0 61.3 49.0 54.2 65.0 40.8 44.7 40.8 52.4 50.0 44.2 49.0 57.0 54.9 50.5 63.8 56.9 -2.1 -1.1 -0.3 -1.2 -0.8 -2.2 -1.6 -1.4 -1.5 -7.1 -2.7 -2.0 -2.0 -2.3 -2,1 0.0 -2.2 -1.8 0.0 -1.7 -1.8 -1.8 -1.1 -2.5 -1.8 -1.0 +1.8 -2.1 -0.9 -1-1.5 -1.1 49.0 -2.0 : 53.4 51.9 -1.5 a Estimated; actual readings valueless on account of reflowing or lieavy rains. Station 2. Spliagnum moss. Station 3. Newly sanded, tliinly vined. Station 4. Newly sanded, lieavily vined. Station o. Peat with moss, heavily vined. Highest and lowest readings are in italics 51936"- -Bull, T— 10 3 Station 6, Old sanded, heavily vined. Station 7. Scalped piece, bare peat. Station 9. Sandy loam on upland. 32 Table 1. — ^Minimum Temperatures in Shelter and in open at 5-incii Height, for Each Station^Togethbr WITH the Difference between Readings, Mather, Wis., 1907 — Continued. Day of month. SEPTEM- BER. 1 2 3 4 5 fi....'... 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 Means Station 2. 65.0 47.0 45.1 45.1 40.9 38.0 56.8 55.9 36.5 35.5 42.2 40.5 44.0 59.4 58.0 65.5 47.6 57.9 60.6 58.8 35.0 29.0 42.8 43.3 25.4 29.3 32.1 38.7 28.9 S5.1 60.9 41.9 40.5 44.7 35.5 33.4 54.9 55.8 30.3 30.3 37.4 36.6 40.3 57.3 53.6 612 43.6 66.0 58.0 57.2 29.5 22.7 37.0 40.3 19.5 24.7 27.0 34.6 24.6 18.8 Station 3. -4.1 -5.1 -4.6 -0.4 -5.4 -4.6 -0.9 -as -6.2 -5.2 -4.8 -3.9 -3.7 -2.1 -4.4 -1.3 -4.0 -1.9 -2.6 -1.6 -5.5 -6.3 -5.8 -3.0 -5.9 -4.6 -5.1 -4.1 -4.3 -6.3 67.1 52.9 50.2 53.4 44.5 41.0 55.6 56.7 39.8 =37.8 46.6 44.6 47.0 59.7 60.1 65.8 52.5 58.3 61.1 59.5 38.5 <"31. 1 44.2 4.3.3 028.0 133.8 33.7 39.0 30.0 26.6 63.8 50.4 47.9 61.0 4.3.0 37.9 56.7 56.6 37.1 "35.3 43.3 42.2 46.1 57.4 57.3 64.8 49.5 57.8 59.6 56.7 36.4 "28.6 41.4 42.0 a26. 6 031.3 31.2 37.2 27.7 23. i S.S -2.5 -2.3 -2.4 -1.5 -3.1 +0.2 -0.1 -2.7 -2.5 -2.3 -2.4 -0.9 -2.3 -2.8 -1.0 -3.0 -0.5 -1.5 -2.8 -2.1 -2.5 -2.8 -1.3 -2.5 -2.6 -2.5 -1.8 -2.3 -3.2 67.5 52.3 49.5 52.7 43.9 40.7 55.8 66.0 39.7 137.2 44.6 43.3 46.6 60.1 59.7 66.0 61.7 58.4 61.0 59.2 37.5 130.5 43.9 43.0 127.4 033.2 33.6 38.7 29.7 26.0 63.4 49.6 46.0 50.0 42.8 38.2 65.9 56.6 36.6 135.2 42.3 40.2 43.8 57.3 56.6 6i.8 48.9 67.6 59.6 57.3 34.0 128.5 40.4 42.7 125 4 131.2 31.3 37.9 27.4 -3.1 -2.7 -3.5 -2.7 -1.1 -2.5 -1-0.1 -1-0.6 -4.1 -2.0 -2.3 -3.1 -2.8 -2 8 -3.1 -1.2 -2.8 -0.8 -1.4 -1.9 -3.5 -2,0 -3.5 -0.3 -2.0 -2.0 -2.3 —0.8 -2.3 -3.6 Station 5. 66.5 50.0 47.0 52.1 43.4 35 7 65.9 153.6 36.0 135.1 41.0 40.5 43.3 69.5 56.9 65.6 46.8 58.0 60.8 69.2 35.6 26.2 43.7 42.7 25.0 26.4 30.0 38.5 26.3 21.7 61.7 45.5 41.3 48.8 41.3 32.6 56.5 150.8 33.7 132.3 36.6 37.0 39.7 54.9 53.0 64.5 43.5 66.1 58.8 56.2 31.1 19.7 39.0 41.7 20.6 22.6 26.1 36.9 23.3 16.6 -4.8 -4.5 -5.7 -3.3 -21 -3.1 -0.4 -2.8 -2.3 -2.8 -4.5 -3.5 -3.6 -4.6 -3.9 -1.1 -3.3 -1.9 -2.0 -3.0 -4.5 -5.5 -4.7 -1.0 -4.4 -3.8 -3.9 -1.6 -3.0 -6.1 Station 6. 66.6 50.6 47.7 52 9 44.0 38.6 66.9 56.7 39.5 136.4 42.6 43.4 45.6 69.7 58.7 66.5 49.0 58.0 60.7 69.2 36.8 27.6 43.9 43.1 26.2 29.5 31.13 38.6 28.0 24.6 62.4 45.7 42.5 50.6 42.3 34.9 56.5 56.4 34.4 133.2 38.7 38.4 41.7 54.8 54.8 64-4 44.0 67.8 68.8 56.2 31.5 20.0 39.3 41.6 20.6 23.7 27.4 37.5 24.6 18.1 -4.2 -4.9 -6.2 -2.3 -1.7 -3.7 -0.4 -0.3 -6.1 -3.2 -3.9 -5.0 -3.9 -4.9 -3.9 -1.1 -5.0 -0.2 -1.9 -3.0 -5 3 -7.6 -4.6 -1.5 -4.6 -6.8 -3.9 -1.1 -3.4 -6.5 Station 7. 66.2 51.5 49.5 52.5 43.0 37.1 55.9 66.7 39.6 33.9 43.2 39.5 44.6 59.3 58.3 65.6 48.0 58.1 60.6 59.4 35.3 27.0 44.0 43.0 26.5 28.8 31.2 38.5 28.0 24.0 62.8 49.1 46.4 61.5 39.4 34.6 55.6 56.8 37.4 31.6 38.9 37.0 41.1 6t.O 55.1 64.8 44.8 68.3 59.5 67.9 31.1 22.7 41.7 42.9 25.0 26.0 28.1 37.0 26.0 20.5 -3.4 -2.4 -3 1 -1.0 -3.6 -2.6 -0.3 -hO.l -2.1 -2.3 -4.3 -2.6 -3.5 -S.S -3.2 -0.8 -3.2 +0.2 -1.1 -1.6 -4.2 -4.3 -2.3 -0.1 -1.5 -2.8 -3.1 -1.5 -2.0 -3.5 Station 9. 69.6 62.6 50.1 52.7 43.8 40.9 56.0 56.7 39.5 38.2 46.6 46.3 48.0 57.0 60.0 65.4 52.3 58.0 60.6 59.5 37.6 30.2 43.6 43.2 27.6 31.6 33.3 38.8 29.8 26.7 66.7 51.4 48.9 52.0 43.6 39.4 56.6 56.7 38.4 36,8 45.4 44.8 46.3 67.4 57.5 64.8 50.4 57.7 59.9 58.6 35.3 27.8 42.4 42.4 26.3 29.3 31.6 38.0 28.6 24-7 -2.9 -1.2 -1.2 -0.7 -0.2 -1.5 +0.6 0.0 -1.1 -1.4 -l.I -1.5 -1.7 +0.4 -2.5 -0.6 -1.9 -0.3 -0.7 -0.9 -2.3 -2.4 -1.1 -0.8 -1.3 -2.2 -1.7 -0.8 -1.2 -2.0 44.3 40.4 -3.9 46.7 44.6 -2.1 46.3 -2.2 44.1 40.7 -3.4 I 45.3 41.7 1-3.6 45.0 42.6 -2.4 46.5 45.3 -1.2 1 Estimated; actual readings valueless on account of reflowing or heavy rains. Station 2. Sphagnum moss. Station 3. Newly sanded, thinly vined. Station 4. Newly sanded, heavily vined. Station 5. Peat with mos's, heavily vined. Highest and lowest readings are in italics. Station 6. Old sanded, heavily vined. Station 7. Scalped piece, bare peat. Station 9. Sandy loam, on upland. 33 Table 1. — Minimum Temperatures in Shelter and in open at 5-inch Height, for Each Station, Together WITH THE Difference between Readings, Mather, Wis., 1907 — Continued. Day of month. OCTOBER 1 2 3 4 5.. 6 ■ 7 8 9 10 U 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 Means Station 2. 31.5 43.3 39.7 32.5 32.7 38. 6 41.3 21.2 39.0 28.9 32.5 27.5 21.0 20.3 43.4 34.0 30. 5 22.7 23.0 26.8 17.7 35.4 26.9 23.3 23.5 18.0 32.5 I5.S 29.3 36.5 33.8 26.6 4S.1 35.7 27.3 27.0 33.7 37.4 15.9 32.8 25.0 26.0 22.7 15.8 15.6 39.4 29.4 27.4 17.6 17.9 21.9 13.2 30.7 21.9 17.7 17.2 12.5 29.4 10.0 25.7 34.8 29.4 30. 25. 2 -4.9 -4.2 -4.0 -5.2 -5.7 -4.9 -3.9 -5.3 -6.2 -3.9 -6.S -4.8 -5.2 -4.7 -4.0 -4.6 -3.1 -5.1 -5.1 -4.9 -4.5 -4.7 -5.0 -5.6 -6.3 -5.5 -3.1 -5.8 -3.6 -1.7 -4.4 -4.8 33.0 SI.S 43.4 38.5 38.3 42.4 45.5 22.7 38.4 31.7 35.0 29.4 21.7 20.4 43.5 36.3 33.4 24.5 23.3 27.3 18.6 36.0 26.6 24.7 25.8 17.6 34.0 ie.7 27.7 36.7 34.0 31.6 30.0 46. e 41.2 34.0 35.1 38.6 42.7 19.5 35.4 28.4 31.0 27.6 19.5 17.8 41.4 34.3 30.7 21.5 19.6 24.6 15.4 32.3 23.6 21.4 22.4 14.4 31.7 13.5 23.5 36.0 29.3 -3.0 -4.6 -2.2 -4.5 -3.2 -3.8 -2.8 -3.2 -3.0 -3.3 -4.0 -1.8 -2.2 -2.6 -2.1 -2.0 -2.7 -3.0 -3.7 -2.7 -3.2 -3.7 -3.0 -3.3 -3.4 -3.2 -2.3 -3.2 -4.2 -0.7 -4.7 28.5 1-3.1 33.2 SS.2 42.7 36.5 37.5 41.5 44.5 21.8 40.0 31.4 34.6 28.8 21.6 19.8 43.6 35.7 32.6 23.6 22.4 26.6 18.4 35.7 26.0 24.7 25.3 18.0 33.7 le.o 28.4 36.8 35.0 29.8 48.8 40.4 32.5 33.7 38.1 41.4 17.7 34.8 27.0 29.7 20.7 16.9 16.8 42.3 33.2 29.4 20.0 16.5 24.7 13.8 29.4 21.0 19.3 21.7 13.1 31.4 10.7 22.3 36.2 31.1 31.2 I 27.4 -3.4 -3.4 -2.3 -4.0 -3.8 -3.4 -3.1 -4.1 -5.2 -4.4 -4.9 -2.1 -4.7 -3.0 -1.3 -2.5 -3.2 -2.6 -5.9 -1.9 -4.6 -6.3 -5.0 -5.4 -3.6 -4.9 -2.3 -5.3 -6.1 -0.6 -3.9 -3.8 Station 5. 29.5 es.o 39.0 33.3 34.8 41.4 41.6 18.8 40.5 31.4 30.6 28.2 17.5 16.0 43.0 33.5 31.5 23.3 18.4 26.3 14.0 34.3 23.6 18.8 25.0 13.7 32.6 11.0 29.1 36.6 34. S 29.2 25.6 46.7 35.5 29.5 30.3 35.6 38.0 12.8 34.0 24.8 28.3 25.9 12.0 12.4 41.5 29.4 28.4 20.7 13.8 23.5 9.8 26.5 18.8 14.7 21.5 9.3 31.6 6.4 21.7 35.7 29.5 25.0 -3.9 -5.3 -3.5 -3.8 -4.5 -5.8 -3.6 -6.0 -6.5 -6.6 -2.3 -2.3 -5.5 -3.6 -1.5 -4.1 -3.1 -2.6 -4.6 -2.8 -4.2 -7.8 -4.8 -4.1 -3.5 -4.4 -1.0 -4.6 -7.4 -0.9 -5.0 -4.2 Station 6. 32.0 5S.5 41.4 35.3 35.1 43.9 44.3 20.1 40.7 32.5 33.4 28.6 19.0 19.5 43.7 35.0 33.7 22.7 21.1 26.6 17.0 35.7 25.7 21.6 26.0 17.5 33.7 14. S 29.6 26.9 47. S 36.8 29.3 28.7 39.0 39.5 14.6 34.9 26.5 28.5 26.2 13.0 14.0 42.0 32.3 29.6 22.5 15.4 24.8 12.5 28.0 20.3 16.0 22.0 11.7 31.6 8.6 22.8 36.3 28.8 30.8 26.1 -5.1 -5.0 -4.6 -6.0 -6.4 -4.9 -4.8 -5.5 -5.S -6.0 -4.9 -2.4 -6.0 -5.5 -1.7 -2.7 -4.1 -0.2 -5.7 -1.8 -4.5 -7.7 -5.4 -5.6 -4.0 -5.8 -2.1 -7.7 -6.8 -O.S -4.5 -4.7 Station ; 31.5 51.9 43.2 35.5 35.3 40.6 42.7 21.5 40.0 31.4 34.4 28.6 20.0 20.4 43.0 34.5 32. S 23. S 21.7 26.5 17.3 34.6 25.8 22.4 26.7 18.0 33.4 14-0 30.3 36.5 35.0 30.8 28.5 4S.0 38.0 30.5 31.7 37.0 40.3 17.5 37.7 28.1 29.5 26.4 16.0 17.0 41.7 32.6 30.8 22.6 19.0 24.5 14.6 29.3 22.7 19.0 25.6 13.7 31.9 11.8 25.8 36.1 30.5 27.7 -3.0 -3.9 -5.2 -5.0 -3.6 -3.6 -2.4 -4.0 -2.3 -3.3 -4.9 -2.2 -4.0 -3.4 -1.3 -1.9 -2.0 -1.2 -2.7 -2.0 -2.7 -5.S -3.1 -3.4 -1.1 -4.3 -1.5 -2.2 -4.5 -0.4 -4.5 -3.1 .station 9. 34.0 51.0 44.8 40.0 40.3 43.8 47.3 22.5 39.6 33.0 34.7 29.0 23.0 21.0 43.4 35.8 3.5. 6 23.6 25.5 27.1 17.5 38.3 28.5 25.7 26.5 16.5 33.7 IS. 4 31.0 36.6 35.5 32.3 32.3 SO.O 43.6 38.4 39.0 41.8 45.3 19.8 37.5 31.5 33.7 28.0 21.6 18.9 42.6 35.5 34.2 23.0 23.0 25.8 15.6 35.7 26.6 23.2 25.3 14.8 33.2 IS. 6 29.0 36.7 34.3 30.8 -1.7 -2.0 -1.2 -1.6 -1.3 -2.0 -2.0 -S.7 -2.1 -1.5 -1.0 -1.0 -1.4 -2.1 -0.8 -0.3 -1.4 -0.6 -2.5 -1.3 -1.9 -2.6 -1.9 -2.5 -1.2 -1.7 -0.5 -1.8 -2.0 +0.1 -1.2 -1.5 Station 2. Sphagnum moss. Station 3. Newly sanded, thinly vined. Station 4. Newly sanded, heavily vined. Stations. Peat with moss, heavily vineii. Highest and lowest readings are in italics. Station 6. Old sanded, heavily vined. Station 7. Scalped piece, bare peat. Station 9. Sandy loam on upland. 34 Table la.— Monthly .\-vd Seasonal Means of Minimum Temperatures in Shelter and in Ope»at .5-inch Height, with Difference Between the Readings^ Mather, Wis., 1907. May." June. July. Aug. Sept. Oct. Means. !> Station 2: o 38.9 37.2 45.4 42.3 61.8 j 49.2 1 50.1 47.1 44.3 40.4 30.0 25.2 43.4 40.2 Difference -1.7 -3.1 -2.6 -3.0 -3.9 -4.8 -3.2 Station 3: 41.4 39.3 48.9 46.3 5S.6 53.0 53.8 51.2 46.7 44.6 31.6 28.5 46.3 43.8 -2.1 -2.6 -2.6 -2.6 -2.1 -3.1 -2.5 Station 4: 41.2 38.8 48.4 45.7 54.9 52.4 53.1 60.6 46.3 31.2 45.8 44.1 1 27.4 43.2 Difference - -2.4 -2.7 -2.5 -2.S -2.2 -3.8 -2.B Station 6: Shelter 39.7 37.2 45.7 41.8 53.1 48.8 50.3 47.1 44.1 ' 29.2 40. 7 25. 43.7 40.1 Difference -2.5 -3.9 -4.3 -3.2 -3.4 ' -4.2 -3.6 Station u: 40.4 38.0 47.0 43.2 53.8 49.6 52.1 48.3 45. 3 30. 8 41.7 26.1 44.9 41.2 -2.4 ; -3.8 -4.2 -3.8 -3.6 1 -4.7 -3.7 Shelter ' Exposed 39.9 37.6 46.3 43.0 53.0 50.2 51.6 49.0 45. 30. 8 42.6 27.7 44.4 41.7 -2.3 -3.3 -2.8 -2.6 -2.4 -3.1 -2.7 Station 9: 41.2 40.1 1 48.4 46.8 55.4 53.8 53.4 51.9 46.5 * 32.3 45.3 30.8 40.2 44. S -1.1 -1.6 -1.6 -1.5 -1.2 -1.5 -1.4 a Means for eighteen days. Station 2. Sphagnum moss. Station 3. Newly sanded, thinly vined. Station 4. Newly sanded, heavily vined. Station 5. Peat with moss, heavilj vined b Mean difference all stations, —2.8°. Station G. Old sanded, heavily vined. Station 7. .Scalped piece, bare peat. Station ',). Sandy loam on upland. 35 Readings of exposed minimum thermometers at the surface and at the 5-incJi. height. — It was found impracticable to place thermometers in the shelters at a lower elevation than 5 inches above the surface of the ground, and consequently readings of instruments exposed at this elevation in the open were used in connection with the discussion of Tables 1 and la. Having found the difference prevailing between mmimum thermometers exposed inside and outside of shelters, it seemed advisable to determine the difference between the readings of the minimum thermometers so exposed in the open and of additional instruments placed at the immediate surface. The cranberry vines extend along the surface, their uprights reaching above several inches, and readings of instruments placed at different elevations at any particular station indicate approximately the temperature which the vmes and leaves experience. Again, the temperature at the immediate surface is naturally largely governed by the conditions of the soil beneath, and the readings of the surface thermometers were therefore needed in comaection with the discussion of soil temperatures. It seemed advisable, as far as practicable, to have the tlierniometers at the 5-mch height placed directly above the surface instruments, in order that the conditions of the soil and vege- tation beneath might be the same for both exposures. This method was followed at all stations except Station 4, where, on account of the special conditions prevaihng, it was found necessary to place the surface minimum on the ground a few feet distant from tlie instrument exposed at the 5-inch height. The vegetation over which the surface thermometer was placed at this station was more dense than at the point where the upper thermometer was exposed, referred to in the discussion of Tables 1 and la. In all cases the lower minimiun thermometers rested upon the ground, although at Stations 2 and 9 they were at the same time fastened to the base of the post which supported other instruments. Were the conditions exactly the same regarding soil and vegetation over a large area at each station, a better comparison would be secured by placing the upper instrument at a point sufficiently removed from the surface thermometer so that it would not shield in the slightest degree the lower instrument, but it is most difficult to secure in a bog surface and soil conditions that are exactly similar for a considerable area. There is certain to be a variation in the character and quantity of the vegetation, and some- times in the character of the soil, even in a small area. These varying conditions may be also considered as factors in the comparison previously made between thermometers exposed in the open and in shelters. Space does not permit the publication of the daily readings of the two exposed minimums at the several stations, but Table 2 shows the montlily and the seasonal averages for the year 1907. The readings were generally higher at the surface than at the .5-inch height, and espe- cialh' so during clear, cool nights. During cloutly and windy weather there was but little differ- ence, and sometimes the surface instrument even registered lower. In fact, at the surface at Station 4, the average for the entire season was slightly lower at the height of .5 inches, but a satisfactory comparison was not possible at that point, for reasons given above. There was also a complication at Station 7, in that these thermometers were placed in the middle of a scalped piece, 10 feet square, surrounded l)y a section of dense sphagnum moss. As stated in a previous paragraph, the instruments were exposed usually over a surface that was representative of a large section of the bog surrounding it, because the temperature naturally is affected by the surface conditions, not only at the point of exposure, but for a considerable area in the vicinity. However, at Station 7 the scalped area was only a relatively small section within an extensive field of sphagnum moss. Moreover, the soil at this station during 1907 was very damp, and the consequent evaporation affected the surface thermometer more than the one at 5 inches. The depression of the thermometers at the .5-inch height was greatest during cold, clear nights, with comparatively high barometer and light wind, when radiation was freest, appar- ently for the same reason that the exposed minimums registered lower than those in shelters. (Table 1.) The moisture resulting from dew, ram, or reflowing sometimes affected the readings of the instruments, especially when water covered the bulbs of the thermometers. For instance, dew occasionally formeil on the bulb of the upper thermometer when the lower was perfectly 36 dry, and at other times the lower thermometer remained wet from rain, the cold of evaporation sometimes lowering the readings of the instrument, especially when rain was followed in the nighttime by wmd. At such times the upper thermometers were usuaUj" higher than the lower ones — an inversion of the usual conditions. Often this difference amounted to several degrees. On the other hand, water fi-om a warm rain remaining on the bulb of a thermometer often sei-ved to raise its reading when the air remained humitl and calm. There seemed to be no uniformity in the variation from month to month, although usually the differences were greatest in October. The average depression of temperature at the 5-inch height beloAv that at the surface for the season of 1907 was 1°. The average depression on clear, cool nights probably reached 4°. There were several instajices of differences exceeding 6°. The greatest average monthly depression of the upper thermometers for any one month was 3°, at Station 5, in October. At Station 4 the lower thermometer averaged 0.4°, 0.5°, and 0.1° lower in May, June, and July, respectively, than the upper thermometer. However, in September and October, at Station 4, '^"' lower minimum averaged, higher than the u])per one hy 0.1° and 0.2°, respectively, and in August there was no difference. The lack in uniformity of the vegetation at Station 4 has been referred to above. In the year 1906 similar data were available for Stations 3, 5, 6, 7, and 9 for the months of August and September. The average depressions of the thermometers at the 5-inch height below those at the surface for the month of August in the years, 1906 and 1907, respectively, were as follows: Station 3, 3° and 2.5°; Station 5, 1.6° and 1.7°; Station 6, 1.2° and 1°; Station 7, 3° and 0.2°; Station 9, 0.6° and 0.7°; for the month of September, 1906 and 1907: Station 3,. 4.7° and 1.3°; Station 5, 2.4° and 2.3°; Station 6, 1.6° and 1.4°; Station 7, 4.8° and -f 0.3°«; Station 9, 1° and 0.3°. It is not easy to state the exact reasons for these great differences m temperature. Of course, the upper thermometers were so placed that there was freer radiation from them than fi-om those at the surface; yet it is not thought that thi- difference in radiation should be sufficient reason for such great differences in temperature, reaching a maximum difference of 6° and even 7° on several nights. The fact that the thermometer exposed at the surface at Station 4 aver- aged lower during more than half the season than the one at the 5-inch height, and that at that station the thermometers were [)laced several feet apart, and not one directly above the other, as at other stations, might suggest that at the remaining stations the surface thermometers generally registered higher because they were shielded by the thermometers immediately above. It is, however, difficult to believe that the very slight interjjosition of the upper thermometer could be responsible for differences of several degrees, as often occurred. The fact that the surface thermometer at Station 4 was located on a surface more densely covered with vegetation than the place where the uj)j)er thermometer at the same station was located should partially account for the apparent inconsistency in the readings at that station. There was so much water at Station 7 in 1907 as compared with 1906 as to seriously affect the comparison of the thermometer readings, and it is because of the great amoimt of evaporation in 1907 at the surface that the lower minimum averaged relatively" lower than in 1906. In a marsh grasses and uprights from the vines interfere slightly with radiation fi-om the thermometers placed on the surface, and it is probable that a thermometer or leaf exposed at an elevation above the surface loses its heat more rapidly by radiation than if it rested upon the surface, because the upper one is not shielded in any way, and while the radiation is going on from the lower one, at the same time heat is being conducted to it from the ground beneath. A thermometer resting upon the surface of the bog becomes a part of the soil or vegetation upon which it rests, as it were, and is benefited by the free conduction of heat to it from the ground, while .the conduction to and tlu-ough the air is very slight in comparison; because of these differ- ences in radiation and conduction, the surface thermometer usuaUy registers a higher tempera- ture than the instrument a few inches above. For the same reason, the temperature of the vegetation at the surface and 5 inches above wouhl var}' as these temperatures have varied, 1 Surface instrument registered lower. 37 especially when the surface vegetation is shielded by vegetation above. It is a matter of common knowledge that in the bogs the cranberries growmg at the tops of the uprights a few inches above the ground are often damaged by frost, while those lying on or near the ground escape injury. ^ ,-„. i. i i- -n The readings of exposed mininuini thermometers at a number of different elevations wiU be discussed in detail later in connection with Tables 13 and 14, in order to show approximately the height above the ground at which the lowest minimum occurs. Table 2.-Monthly and Seasonal Means of Minimum Temper.'^.tuees in open at Surface and at 5-inch Height, with Difference Between the Readings, Mather, Wis., 1907. May." June. July. Aug. Sept. Oct. Means, b Station 2: Surface 5 inch 37.6 37.2 43.3 42.3 52.0 49.2 49.4 47.1 41.9 40.4 27,5 25. 2 j 41.9 40.2 Difference -0.4 -1.0 -2.8 -2.3 -1.5 -2.3 -1.7 Station 3: 40.4 48.8 39.3 ■ 46.3 55.5 53.0 53.7 51.2 45.9 44.6 28.8 45.5 5 inch 28.5 43.8 Difference. . . -1.1 j -2.5 -2.5 -2.5 -1.3 -0.3 -1.7 Station 4: :!S. 4 45. 2 38.8 , 45.7 52.3 62.4 50.6 50.6 44.2 44.1 27.6 27.4 43.1 5 incti 43.2 Difference +0.4] +0.5 +0.1 0.0 -0.1 -0.2 +0.1 station 5: :C A 43.5 37.2 41.' 8 49.8 48.8 48.8 47.1 43.0 40.7 28.0 25.0 41.7 5 inch 40.1 Difference +0.1 1 -1.7 -1.0 -1.7 -2.3 -3.0 -1.6 Station 6: 38. 7 44. 38.0 1 43.2 50.3 49.6 49.3 48.3 43.1 41.7 28.3 26.3 42.3 5 inch 41.2 Difference -0.7 -0.8 -0.7 -1.0 -1.4 -2.0 -1.1 Station 1 : Surface 5 inch 37. fi 44. 37.6 43.0 51.2 50.2 49.2 49.0 42.3 42.6 27.9 27.7 42.0 41.7 Difference 0.0 -1.0 -1.0 -0.2 .+0.3 -0.2 1 -0.3 Station 9: Svirface 5 inch ' 40.9 1 48.7 40.1 46.8 55.0 53.8 52.6 51.9 45.6 45.3 31.1 30.8 45.6 44.8 -0.8 -1.9 -1.2 -0.7 -0.3 -0.3 ' -0.8 ' o Means for eighteen days, station 2. Sphagn\im moss, station 3. Newly sanded, thinly vined. station 4. Newly sanded, heavily vined. Station 5. Peat with moss, heavily vined. b Mean difference all stations, 1.0°. Station 6. Old sanded, heavily vined. Station 7. Scalped piece, bare peat. Station 9. Sandy loam on upland. Ohservations of temperatures in soil and at the surface in different locations, 3Ia the r, Wis., 1906 and 190?.— This discussion has already shown that there is a wide difference in temperature at various points at the surface and a few inches above, in the same bog, and that the vegetation in ])ottom lands is subjected to temperatures of varymg degree. It seemed desirable to deter- mine what relation, if any. exists between the temperature at and near the surface and the character of the soil and its covering. Observations made at Mather, Wis., durmg 1906 and 1907 of soil temperatures in connection with exposed thermometers above the surface furnish interesting data bearing on this subject . The average readings are herewith given for September, 38 1906, for four selected stations, this being preliminary to the more extensive obsew^ations of the following year. ' Average Temperatures for September, 1906, Mather, Wis. Maximum soil temperature, 3 inches- Minimum soil temperature, 3 inches. Nightly loss of soil heat, 3 inches Exposed minimum at surface Station 3. Station 4. Station li. . „ . 64.2 ti3.2 (il.l .if.. 1 .59.1 39.1 8.1 4.1 2.0 51.2 1 47.9 44.2 Station .5. 59.8 59.2 Station 3. newly sanded and thinly vlned, representing best conditions of sanding, draining, and cultivating, station 4. newly sanded and heavily vined, representing best conditions of sanding and draining. Station G. old (9 years), sanded and heavily vined, stratum of peat, 1 inch in thickness, over old sand. Station 5, uncultivated marsh, peat, and sphagnum moss, poorly drained. The soil thermometers were placed at a deptli of 3 incites, and it was found by a series of eye observations and by comparison with the soil thermograph traces that the maximum soil temperatures usually occurred at about 6 p. m. and the minimum soil tem])eratures at about 7 a. m. (See Fig. 20, showing average hourly soil thermograph reatlmgs at Stations 3 and 5, Mather, Wis., 1907.) The above table shows that the highest maximum soil temperatures and the lowest minimum soil temperatures at the depth of 3 inches and the highest exposed minimums occurred in the sanded sections, bare or thinly vined and well dramed, while the lowest maximum soil temperatures, the highest minimum soil temperatures, and the lowest exposed minimums were founil in the uncultivated marsh, which was poorly drained and had a thick growth of vegetation and sphagnum moss. Prof. W. J. Humphreys" says: ''The better the absorber, other things being eciual, the warmer it gets during insolation and the more it heats the air, while the better the radiator it is, thte colder, as a rule, it and the air adjacent become during the night. When the atmosphere is clear and tlry, and therefore diatheimanous, the cooling of objects and their liability to fi'ost depends largely upon their capacity to radiate at ordmary temperatures. A good radiator under these conditions loses heat partly by radiation through the atmosphere to space. It cools rapidly, but the heat it gives off does not all go to wanning the air, for, as ex]ilained, a part of it is directh' lost to space. On the other hantl, an t)bject that radiates poorly gives off heat slowly, and what it tloes give off is in a large measure by conduction to the atmosphere. It tentls to conserve both its own temperature and that of the surrounding air, and thereby diminishes the probability of frost." As stated before, during the day the surface of any solid upon which the sun shmes becomes hotter than the air above it. A thermometer resting upon the ground becomes a part of the soil or vegetation, as it were, and the readmgs of the instrument indicate relatively high or low maximum temperatures in the daytime and relatively high or low minimum temperatures at night, de])ending upon the radiation, absorption, and conduction of heat under the various existing <'onditions. The vegetation as found in the bogs is an excellent radiator and absorbs well, but of ('ourse conducts and transmits heat to the soil very slowly. The heat lost from vegetation is largely by radiation tlirough the air without heating it sensibly. Peat soil is also a good absorber and radiator, but it is a poor conductor; but the heat received at the surface is partly conducted into the peat. The sanded surface is not as gooil an absoi'ber, but it is a much better conductor of heat. The heat, moreover, of the sand in the j)iesence of air is lost lai'gely by conduction to it, and conse([uently serves to heat tiie air lyhig immediately above — in strong contrast to the conditions over a heavily vined surface or plain peat, where the loss is mainly by radiation. A knowledge of these facts is important in connection with the more extensive observations made at Mather during the season of 1907, readings of exposed maximums antl of exposed " Bulletin of the Mount Weather Observator)', Vol. II, pt. 3. 39 minimums being; made as well as of soil temperature. The Stations 3, 4, 5, and 6 selected are fairly representative of the conditions prevailing in a cranberry bog. Only the summary of the conditions for 1907, inchuling maximum and minimum averages, appears in Table 3. There is not sufficient space for the daily readings. Four stations, as in the previous year, are suffi- cient for this comparison, and an additional number would merely repeat the results here furnished. The readings of the maxinnim and the minimum thermometers are from instru- ments exposed in the open at the surface. The soil thermometers at the various stations were placed at a depth of 3 inches in the vicinity of the surface thermometers. For purposes of this discussion it would have been better if the bulbs could have been placed just beneath the sur- face. But in a bog it is rather difficult to determine where the actual surface begins, as it is generally covered with vines, grasses, leaves, and decaying vegetation, gradually turning to peat. '^Vliere the vegetation is dense, the effective surface is actually above the surface of the soil. The sanded surfaces differ radicall}^ from the surfaces that are not sanded. On account of these circumstances and because of the difficulty of maintaining the soil thermometers in an upright position, except at a moderate depth, so as to firmly secure them, no attempt was made to obtain readings of the soil temperature at a depth less than 3 inches. In the original tables, of winch Table 3 is the summary, the readings of the soil thermometers which were made at 6 p. m. are entered under the succeeding date, and the differences between these readings and the following 7 a. m. readings show the nightly loss or range in soil temperature. The difficulty in an investigation of this kind is to maintain uniform conditions at the various stations, so that data may be fairly comparable at all times iluring tlie season, i)ut this is quite impossible, as the vegetation is likely to remain uniform at one station, while at other stations it may either increase or decrease in density. During the season of 1907 the conditions at Stations 3 and 4 changed but little, the surface at Station 3 being relatively clean, wliile at Station 4 the vegetation remametl dense. The vines at Station 5 were dymg out after mid- summer to such a degree as to seriously affect the readings of the instruments. In fact, twice during the month of August a change in the location of the soil instruments was made in order to counteract the changuig conditions. The density of the vegetation at Station 6 steadily decreased as the end of the season approached, but there was no change in the location of the uistruments as at Station .5. If the cranberry vine were a bush, as some jjcople believe, theie would not be much difficulty in maintaining uniform conditions of foliage, but it is a vine spreading in all directions fiom the crowii, so that constant trampling at one place often affects the condition of the vegetation several feet distant. There is, for the reasons given above, a greater uniformity in the readings at Stations 3 and 4 than at the other stations. At Station 3 for the entire season the exposed maximums averaged the lowest and the exposed minimums and the 6 p. m. soil temperatures the highest, although the 7 a. m. soil temperatures averagetl the lowest. At Station 5 the exposed maxi- mums averaged the highest from May to August, inclusive, but in September the maximum at Station 4 was slightly higher and in October much higher than at Station 5. The lack in uniformity was undoubtedly caused by the steady change in vegetation at Station 5, as referred to above. This change at Station 5 is also apparent in the comparison of the minimums at Stations 4 and .5, the average minimum in October at Station 4 actually being lower by 0.4° than at Station .5, while in the other months it was considerably higher. The persistency of the dense vegetation at Station 4 until the end of the season is quite apparent from the read- ings of the instruments, especially in October. It was at Station 4 that the surface minimum averaged lower than at the 5-inch height, as referred to in the discussion of Table 2. On account of the enforced change of the soil instruments at Station 5 in August, these readings are not strictly comparable in September and October with the soil data at the other stations. At Stations 4, 5, and 6 the soil was so shielded from the sun's rays as to prevent its warm- ing to any great degree, much of the absorbed energy being used to produce plant growth and evaporation, and consequently the loss or range of heat was small as compared with that at Station 3. The difference in range of soil temperature at the 3-inch depth at certain stations, 40 caused b}^ variation in soil and covering, at Mather, Wis., is graphically shown. in figure 19; also in Figure 20, which shows the average hourly soil temperature at depths of 3 and 6 inches at, Stations 3 and 5. "While the 7 a. m. or mininiiini soil temperature readings at the depth of 3 inches at Station 3 averaged lower than at the otlier stations, it is probable that the minimum temperature of the soil at the immediate surface at Station 3 averaged higher than at tlie other locations, because the exposed minimum temperature was higher. As the exposetl maximum tempera- ture at the various stations was affectetl by the vegetation, so also was the exposed minimum, i^, ,^iy.. 4 i - '^/.■. < . ~,W/ , i < ■■\f: , f . -mi. , -■:J/-/-:1/-"/- ..yt: , / , ..j-j'.' ^ < . • (/■• ' ■ ■ r ■■ > • V, ^t=f 23 21 ■jr, 'jG ! ■ ! : 27 /;//-; ^v — ^--■' z . -. i : L t - ■ ; :.: . ^—1^-+^^ .-: "llTTTTTJTTT '•i'~ ^' ' ' ' ' J30 r- .631- -^- (*> ■ ^ — ■■ ■ - - Fig. 19.— Soil temperature curves at three inch depth for Stations 3, 4, and 5. Mather, Wis., September 23 to 30, 1906. Station No. 3, soil temperature in bog newly sanded, thinly vined, 3 inches deep : station No. b. soil temperature in peat bog with moss 3 inches deep - - - - . : station No. 4. soil temperature in bog newly sanded, heavily vined, 3 inches deep — x — x — x — x— x — . the lowest miuimums prevailing generally at the stations where the maximums were tiie highest. Obviously the uicreasing vegetation, serving to raise the exposed maximum in the daytime, was also responsible for the great radiation at night, especially during clear weather, and as a consecjuence the miniinums were lowest wliere the vegetation was densest and highest where it was thimiest. "Wliile the loss of heat at night from the vegetation is largely by radia- tion and through the air without warming it, at places where the surface was sanded the loss of heat was partly by conduction to tiie air above. .Although the vegetation was dense at Station 4, the surface had been recently sanded, and the surface at Station 6 had been sanded in 1898. Tlie influence of this sand- ing at wStation 4 and even at Sta- tion 6 is apparent in the readings of the maximum soil tempera- ture, the range in soil temperature, ami the exposed minimum tem- perature, as compared with similar readings at Station 5, although a layer of peat an inch in thickness had formed over the sand at Sta- tion 6. The vegetation at all thi-ee stations was ilense and prevented great heating of the soil, but nev- ertheless the sand, being a better conductor of heat than the peat. Fig. 20.— (1) Traces showing average hourly soil temperature for the .season of 1907 brought a trreater SUPplv of llCat at a depth of 3 inches and (1 inches. Station 3. Mather, Wis. (3 inches _^^. . ^ , -T i' . . 6 inches .) (2) Traces showing average hourly soil tempera- l^to the SOU, tllUS Conserving it to tures for the season of 1907 at depths of 3 inches and 6 inches. Station 5, Mather, be "iven off later at uio'ht bv Con- Wis. (3 inches 6 inches .) "^ . , . . '' -^ ' duction and radiation. The sand, then, was probably as much responsible as the better drainage for the higher exposed mhii- mum temperatures at Stations 4 and 6, as compared with Station 5, the drainage at both Stations 5 and 6 being relatively poor, resulting in a consideraldo loss of heat through evap- oration of the moisture at the surface. The conditions at Station 6 resembled those at Stations 4 and 5 equally, because although the vegetation at Station 6 was dense until after midsum- mer, it graduallv died away, and for this reason the exposed maximums averaged during October even lower than tho.se at Station 3. -1:1 These observations in 1907 confii'm those of 1906 in that the highest maximum soil tem- peratures and the lowest minimum soil temperatures at the depth of 3 inches, the greatest range in soil temperature, and the highest exposed minimums occurred in the thinly vined, well drained, and sanded sections, wliile the lowest maximum soil temperatures and highest minimum soil temperatures, the least range m soil temperature, and the lowest exposed mini- mums were found in the uncultivated marsh, which was poorly drained and heavily vined. Moreover, the highest average exposed maximums occurred where the vegetation was dense, while the lowest average maximums occuned in tlie sanded and tlunly vined section. Other things being equal, the higher the maximum temperature on any one day the higher was the maximum soil temperature at the depth of 3 inches and the ensuing exposed minimum tem- perature. Again, other things being equal, the higher the maximum soil temperature on any one day the higher was the ensuing exposed minimum temperature. In other words, there was a close relation between the daily maximum air temperature and the soil temperature and a close relation between the soil temperature and the ensuing exposed minimum temperature. It is for this rea.son that in the spring and fall, when the ground is cold, frost occurs in the bogs much more eivsily than in the summer, when the soil is warm. The high exposed minimums at Station 3, as compared with those at the other stations, are ((uite remarkable, and the advantages from cultivation, draining, and sanding are well illustrated. The difference between the minimum temperatures at Station 3 and at the other stations is least in October, ami this is probably because frost had entered the surface of the soil. WTiereas sand during the crop season is most valuable in warding off low night tem- peratures, it is probable that after frost has once entered the soil its character is not of much consequence, ^\^lile the exposed maximums on cloudy daj^s varied little at the different sta- tions and did not reach a high degree, the minimum temperatures on cloudy nights differed little and were relatively Irigh. There was, moreover, but little difference between the mini- mums on windy nights. At no station during the season did the temperature of the soil at the tlepth of 3 inches fall to the freezing point, the lowest reading being 33.8° on the morning of October 2S at Station 3. On the same day the readings at the other stations were as follows: Station 4, 37.1°; Station 5, 40.3°; and at Station 6, 37°; but at all stations on the bog the ground at the immediate surface was frozen. The range in the exposed minimum temperature at the surface of a bog, as sho-WTi by Tables 2 and 3, does not, of course, actually represent the extremes, the exposed minimums at the 5-inch height as a rule registering lower than those at the surface. In later tables embody- ing the daily readings of the exposed minimums, both at the surface and 5 inches and then- respective differences, will be showm in detail the extreme differences at the coldest and the warmest places on the bogs. The highest exposed maximums were reached about July 20, the greatest being 128.1° on that date at Station .5. On the same date the exposed maximum at Station 3 was 110°; at Station 4, 121.7° ; and at Station 6, 120°. The soil temperature readings at 6 p. m. at Stations 4, 5, and 6, reached their maximum from four to five days later, there being an irregular increase from the beginning of the season in May to the summer maximum, and, in turn, a decrease from the maximum to the minimum near the end of October. The highest soil temperatures at the various stations in July were as follows: Station 3, 76.3° on the 20th; Station 4, 69.7° on the 24th; Station 5, 71° on the 25th; and Station 6, 71.5° on the 24th. The maximum of the season, however, at Station 3, in the tliinly vined and sanded section, was not reached until August 31, when a temperature of 78° was registered. The exposed maximums at Station 3 seldom registered higher than 110°, but at Stations 4, 5, and 6, where the vegetation was dense, the readings frequently exceeded 120°. The greatest daily range between the exposed maximum and the exposed minimum at any one station was at Station 5, 89.9°, on July 2, from a maxmmm of 119.9° to a minunum of 30°. The daily range in exposed temperature was seldom less than 20°, except at Station 3. At that station there were a few instances of ranges less than 10° in October, and one or two others during the balance of the season. 42 There is, of course, a direct relation between the air temperature and the soil temperature, an increase of heat during tlie day serving to raise tlie temperature of tlie soil; and this, in turn, prevents low minimum temperatures at night. Where the air temperature was low in the daytime, and, as a result, the soil remained cold, low minimum air temperatures were sure to follow, provided the weather at night was clear, so as to permit free radiation of heat. While usually there was a loss of heat from the soil at night, occasionally the temperature of the soil rose. On October 2, during a cloudy, warm night, following a cold day, the tempera- ture of the soil rose at the various stations, the increase reaching a maximum of 1.7° at Station 6. On certain cloudy, warm nights there was a slight rise in the soil temperature at Stations 4, 5, and 6, while a fall occurred at Station 3. The greatest nightly loss in soil temperature was at Station 3, 17.8° on October 18, from a maximum of 57° to a minimum of 39.2°, while at the other stations the nightly loss in soil temperature seldom exceeded 5°. The range in soil temperature is a measure of the heat absorbed during the day and lost at night by the soil, and responils from day to day to changes in insolation. The amount of heat received in the daytime by the soil at the different locations is shown in a measure by the 6 p. m. soil-temperature readings. At the 3-inch depth the average for the season of 1907 at Station 3 was 62.6°, as compared with 58° at Station 4, 56.6° at Station 5, and 57.2° at Station 6. (Tables 3 and 19.) Moreover, at the 6-inch depth, the average soil- temperature readings were as follows: Station 3, 59.8°; Station 4, 56.2°; Station 5, 55.2°; Station 6, 55.6°. These figures not only show that the temperature of the soil near the sur- face in the thinly vined and sanded section is usually much higher than in the other sections, but also that the heat reaches to a greater depth. In this connection, see Figure 20, showing the soil-temperature curves at both 3 and 6 inches at Stations 3 and 5 for the season of 1907. The range in temperature of the soil immediately beneath the surface is untloubtedly greater than at the depth of 3 inches. It should be evident that where the soil temperatures are high, more heat may be lost by conduction and radiation from the soil before the point of critical air temperature at or immediatelj' above the surface is reached, even if the loss by radiation tlirough the air be at the same rate at all locations. However, the radiation from a peat bog with a heavily vined surface is much freer than where the surface has been sanded antl is thinly Arined, the loss of heat from the latter j)robably being largely by conduction to the air, and there- fore slower. The sanded and thinly vined surface conserves the heat, not only in the soil, but also in the air immediately above, while a dense growth of vegetation prevents the soil beneath from being heated considerably in the daytime. The degree to which the temperature falls during the night depends largely upon the warmth of the soil, and when the heating during the day has been slight, and the ensuing night is clear, thus permitting rapid radiation, low minimum air temperatures must result, as stated above. It is apparent from tills discussion that the air temperature is controlled largely by the character of the soil and its covering. Such a remarkable variation as is here shown explains why frost may visit one portion of a bog, while another portion may escape injury. On any clear, cool night the cold air, as it settles gradually through gravity, overspreads the bog, and here and there are found warm places and cold places and others having an intermediate value, depending upon the character of the soil and its covering. It is as if heaters of varying power were scattered over the bog, giving off heat to the air immediately above, some in greater quantities and others in less. The difference in temperature of a surface covering is some- times apparent when the first light snow falls in the autunm or early winter, before the ground becomes cold, the snow melting where the ground is bare of growth, but remaining where the vegetation is dense. Likewise, under similar conditions, snow melts when it falls upon a concrete walk, though remaining on a board walk; and the first frost of the .season is always seen on the latter. The heat stored in the bare soil and in the concrete walk is conducted to the surface, and affects the temperature at the surface as does a sanded and thinly vined soil in the bogs. Figures 21 and 22 will supplement Table 3. 43 Table 3. — Monthly and Seasonal Mean.s of Ma.ximum and Minimum Temperatures at Surface in Open, with Range; also Means of Soil Temperatures, 3-inch Depth, and of Loss during the Nioht, Mather, Wis., 1907. [The G p. m. soil temperatures occurred the previous day.] May." June. July. Aug. Sept. Oct. Means. Station 3: Surface— 79.5 40.2 95.7 48.8 99.6 55.5 89.9 53.7 80.9 .45.9 62.1 28.8 84.6 39.3 46.9 44.1 36.2 35.0 33.3 39 1 Soil, 3 inch— 56.3 48.0 65.9 56.9 71.8 63.1 68.6 61.4 63.2 55.3 49.6 41.9 -7.7 62.6 54 4 Loss -8.3 -9.0 -8.7 -7.2 -7.9 -8.2 Station ■!: Surface— 84.5 38.2 103.4 45.2 110.1 52.3 99.4 50.6 85.4 44.2 72. 7 27.5 92.6 46.3 58.2 57.8 48.8 41.2 45.2 49.6 Soil. 3 inch- 50.5 47.6 60.2 56.5 66.9 63.2 64.6 61.5 59.3 56.5 46.6 44.0 58.0 64.9 -2.9 -3.7 -3.7 -3.1 -2.8 -2.6 -3.1 Station 5: Surface- 84.7 36.8 104.4 43.5 112.2 49.8 101.3 48.8 85.0 43.0 64.7 27.9 92 fl Minimum. 41.7 Range 47.9 60.9 62.4 52.5 42.0 38.8 50.3 Soil, 3 inch— 48.6 47.6 57.9 55.6 66.2 63.6 64.0 62.1 57.2 56.5 45.9 45.5 56.6 7 a. m 55. 1 Loss -1.0 -2.3 -2.6 -1.9 -0.7 -0.4 -1.5 Station ti; Maximum .... . 80.1 38.6 99.8 44.0 105.9 50.3 97.1 49.3 81.4 43.1 6I«1 28.3 87.4 42.3 41.5 55.8 55.6 47.8 38.3 3L8 45.1 Soil, 3 inch— 6 p. m 49.5 47.3 59.1 56.3 65.9 63.4 63.6 61.4 58.5 56.3 46.6 44.6 57.2 64.9 -2.2 -2.8 -2.5 -2.2 -2.2 -2.0 —2.3 1 Means for sixteen days. Station 3. Newly sanded, thinly vined. Station 4. Newly sanded, heavily vined. Station 5. Peat with moss, heavily vined. Station G. Old sanded, heavily viupd. Air temperatures and soil temperatures at Station 7 and Station 7a, Mather, Wis., September, 1906. — The facts brought out by the comparative data appearing in Table 3 are accentuated by obsers^ations made in 1906 at Station 7, and at a supplementary station, 7a, which show how much the minimum temperature at an elevation above the surface depends upon the environment. When the investigation was commenced in 1906 at Mather it seemed desirable to have one station located in a section of plain peat, absolutely free from vegetation. No such section was available, nor was it practicable to scalp a portion of the cranberry marsh proper for the purpose. An area, however, 10 feet square, in the midst of an extensive field of sphagnum moss, immediately outside, was cleaned up. Thermometers were placed in the 44 center of the scalped piece, Station 7, and 5 or 6 feet distant over the moss, Station«f«, near the edge. Station 7a was not continued in 1907, and as Station 7 itself was under water for a considerable portion of the same year, data for 1907 at that Station are not as serviceable as they otherwise might be. Data for September, 1906 (Table 4), furnish some interesting results. The average exposed minimum at the surface of Station 7 was much higher than at the surface at Station 7a, there being a difference of 5.6°. On every day the minimum was higher at the surface of Station 7 than at the surface at Station 7a, with but a single exception, and a maximum difference of 11° occurred on September 25 — a remarkable variation in tem- perature within a distance of 5 or 6 feet. Tliis is because, in a soil covereil with a thick layer of moss, the opportunity for conduction down is not good, and much of the absorbed solar energy is used in proilucing plant growth. Thus the moss-covered soil does not store up as much sensible heat as does the bare soil, although the moss and the bare peat are equally good radiators. The difference between the average minimums for the month at an elevation of 5 inches, however, was only 0.5°, Station 7 still reading higher on the average, although there were several instances where it was lower. The minimum, at the 5-inch height at Station 7 averaged 4-8° lower than at the surface, while at Station 7a the temperature at 5 inches aimraged 0.3° higher than at the surface. This inversion of the usual conditions at Station 7a was doubtless caused by the warmth from the area of bare soil adjoining. In other words, the temperature at the 5-inch height over the bare peat at Station 7 was affected by the surrounding area of sphagnum moss, and consequently lowered, while the temperature over the adjoining moss at Station 7a was affected in the other direction, but in a lesser tlegree, by the small area of bare peat imme- diately adjoining. There was probably a slow circulation of air at night between the moss and the bare soil. These results indicate quite plainly that while the temperature at the surface depends upon the character of the soil and vegetation at the point of exposure, the temperature a few inches above is affected not only by the character of tliis vegetation and the soil immediately beneath, but by the environment as well. If the scalped piece were greater in extent, 40 or 50 feet square or more, the thermometers exposed in the center of the area 5 inches above the ground would probabh^ not be considerably affected by the surrounding moss. The thermometer on the moss, however, near the edge of tliis larger scalped piece, would, on the other hand, be affected even more than in the case of the small 10-foot area used in this investigation. Table 4, under the soil-temperature column, at the .3-inch depth, illustrates the great range in temperature of the clean soil as compared witli that covered with a dense growth. The avejage 6 p. m. i-eading at Station 7 was 65.8°, as compared with 61.3° at Station 7«. The maximum soil temperature was 73° at Station 7 on September 12, wliile it was only 63.8° at Station 7a on the same day. The average loss of heat during the night at Station 7 was 6.1°, as compared with 0.2° at Station 7a, while the minimum, or 7 a. m. soil reachngs, averaged lower at Station 7 than at Station 7a, at the 3-inch depth. The greatest loss in soil tempera- ture at both stations was on September 14, 11.2° at Station 7, and only 1.2° at Station 7a. On September 16, during a warm, rainy night, following a cool day, the soil temperature at Station 7 actualh' rose 0.5°, while at Station 7a the rise was 0.6°. On the night of September 2 the soil temperature at Station 7 rose 0.2°, wliile at Station 7a the rise was 0.4°. These were the only instances where the temperature rose in the nighttime at Station 7, but there were a number of instances where the temperature rose at Station 7a, its soil being so protected from the sun's rays that the change in temperature was not only small, but lagged behind that at Station 7. The moss loses its heat rapidly and receives heat from below but slowly, partl}'^ because the supply there is not great and partly because the connection, being mainly through the stems, is not such as to give good conduction. On the other hand, the bare peat soil has a good supply of heat to draw upon and has direct connection Avith the atmosphere above. \¥lnle the minunum temperature at the depth of 3 inches was lower in the bare section than in the moss, it is quite certain that at the immediate surface the temperature in the bare soil was higher. It is apparent that the bare soil conserves the heat, while a soil covered with a dense growth, such as moss, is heated but little by the sun's rays, an exposed minimum there- 45 fore at the immediate surface of the clean section registering much higlier than over the moss. The varying temperature of tlie ground is furtlier evidenced l)y tlie habits of cattle in pasture. On warm summer nights they lie down where the ground is covered with grass, so as to be cool, while on cool, clear nights they seek the warmer bare soil. Table 4. — Minimum Temperatures in Open at Surface and 5-Inch Height, Together with Differences: also Soil Temperature Readings Showing Loss during Night, Mather, Wis., September, 1906. [The 6 p. m. soil readings are those which occurred the previous day.] Station 7 (over bare peat). Station 7a (over sphagnum moss). Day of month. Surface. 5 inches. Differ- ence. Soil temperature, deep. 3 inches Surface. 5 inches. Differ- ence. Soil temperature, deep. 1 inches 6 p. m. 7 a. m. Loss. 6 p. m. 7 a. m. Loss. 1 2 3 4 5 43.5 61.6 42.5 41.4 40.0 42.4 49.0 52.2 53.1 60.8 61.5 62.2 50.3 36.2 47.0 SB. 5 60.7 62.4 55.4 56.0 54.1 50.7 46.7 44.0 45.0 45.8 33.2 36.7 43.0 29. S 38.8 60.7 35.0 35.0 32.4 35.7 43.4 46.8 47.2 56.0 ei.8 59.5 47.2 29.3 45.0 61.0 57.4 58.3 51.1 53.3 49.5 44.3 40.2 37.5 36.8 41.5 27.0 30.4 42.0 2B.S -4.7 -0.8 -7.5 -0.4 -7.6 -6.7 -5.6 -5.4 -5.9 -4.8 +0.S -2.7 -3.1 -6.9 -2.0 -1.5 -3.3 -4.1 -4.3 -2.7 -4.6 -6.4 -6.5 -6.5 -8.S -4.3 -0. 2 -6.3 -1.0 -6.8 65.3 62.1 65.2 67.0 67.0 66.5 67.8 69.8 71.3 72.8 71.0 73. 09.2 67.0 62.2 61.6 68.3 70.3 71.2 69.4 65.4 07.0 60.5 .59.7 62.5 63.3 61.3 61.0 57. S 59.0 57.8 62.3 58.5 57.3 57.3 57.2 60.3 61.8 62.9 66.3 er.B 67. s 62.5 55.8 51.8 62.1 64.3 65.8 64.7 63.5 02.4 60.8 57.8 56.2 56.4 59.5 52.0 52.7 56.5 p. 8 - 7.5 + 0.2 - 6.7 - 9.7 - 9.7 - 9.3 - 7.5 - 8.0 - 8.4 - 6.5 - 3.8 - 5.8 - 6.7 -11. S -10.4 + O.S - 4.0 - 4.5 - 6.5 - 5.9 - 3.0 - 6.2 -2.7 - 3.5 - 6.1 - 3.8 - 9.3 - 8.3 - 1.3 - 9.2 37.8 61.0 32.2 34.4 31.1 •36.0 43.2 46.4 47.3 55.2 62.0 60.1 47.3 29.0 44.3 . 6S.0 57.1 57.8 49.2 54.0 48.8 42.8 40.0 35.8 34.0 38.0 26.9 28.4 35.0 24. S 36.0 61.2 31.0 34.0 30.6 35.5 43.7 47.0 47.0 57.8 57.9 60.4 48.3 28.1 46.0 6S.S 58.0 58.2 51.2 54.1 50.2 43.2 41.1 36.0 35.2 40.3 25.3 29.0 42.2 20. S -1.8 +0.2 -1.2 -0.4 -0.5 -0.5 +0.5 +0.6 -0.3 +2.6 -4.1 +0.3 +1.0 -0.9 + 1.7 +0.3 +0.9 +0.4 +2.0 +0.1 +1.4 +0.4 + 1.1 +0.2 +1.2 +2.3 -1.6 +0.6 +T.S -4.0 61.0 60.8 61.8 61.3 60.8 60.3 60.3 60.8 61.4 62.1 62.8 63. 8 63.8 62.8 61.0 60.3 61.9 63.0 63.7 63.5 63.0 62.8 61.8 60.7 60.1 59.8 59.7 60.7 61.2 61.5 60.8 60.4 60.0 60.4 61.0 61.6 02.5 63.3 63. 3 63.4 61.6 60.3 60.9 62.4 63.3 63.7 63.2 62.8 62.2 61.1 60.0 60.0 60.2 58.7 -0.3 +0.4 -0.3 -0.5 -0.4 6 -0.3 7 +0.1 8 +0.2 9 +0.2 10 +0.4 11 +0.5 12 +0.1 13 -0.4 14 -1.2 15.... -0.7 16 +0.6 17 . . +0.5 18 +0.3 19 0.0 20 -0.3 21 -0.2 22 -0.0 23 -0.7 24 -0.7 25 -0.1 26 +0.4 27 -1.0 28 58.2 57.7 S7.S 57.8 57.8 57.0 -0.5 29 +0.3 30 -O.S Means 49.0 44.2 -4.8 65.8 59.7 -6.1 43.4 43.7 +0.3 61.3 61.1 -0.2 Highest and lowest readings are in italics. 46 Table 4. — Comparison of Minimum Temperatures at Stations 7 and 7a, Mather, Wis., September, 1900. Dav of month. 1 2 3 4 5 C S 9 10 11 12 13 14 15 IG 17 18 19 20 21 22 23 24 25 20 27 28 29 30 Means Surface. Station 7. Station 7a. Difference. 43.5 61.5 42.5 41.4 40.0 42.4 49.0 52.2 53.1 60.8 61. 5 62.2 50.3 36.2 47.0 ei.s 60.7 62.4 55.4 56.0 54.1 50.7 46.7 44.0 45.0 45.8 33.2 36.7 43.0 S9.3 49.0 37.8 61.0 32.2 34.4 31.1 36.0 43.2 46.4 47.3 55.2 es.o 60.1 47.3 29.0 44.3 62.0 57.1 57.8 49.2 54.0 48.8 42.8 40.0 35.8 34.0 38.0 26.9 28.4 35.0 2i.3 43.4 - 3.7 - 0.5 -10.3 - 7.0 - 8.9 - 6.4 - 5.8 - 5.8 - 5.8 - 5.6 + O.B - 2.1 - 3.0 - 0.5 - 3.6 - 4.6 - 6.2 - 2.0 - 5.3 - 7.9 - 6.7 - 8.2 -11.0 - 7.S - 6.3 - 8.3 - 8.0 - 5.0 - 5.6 5-inch height. Station 7. Station 7ii. Difference, 38. 60.7 35.0 35.0 32.4 35.7 43.4 46.8 47.2 56.0 61.8 59.5 47.2 29.3 45.0 61.0 57.4 58.3 51.1 53.3 49.0 44.3 40.2 37.5 36.8 41.5 27.0 30.4 42.0 gl.S I 44.2 36.0 61.2 31.0 34.0 30.6 35.5 43.7 47.0 47.0 57.8 57.9 60.4 48.3 28.1 46.0 6£.S 58.0 58.2 51.2 54.1 50.2 43.2 41.1 36.0 35.2 40,3 25.3 29.0 42.2 20.3 43.7 -2.8 +0.5 -4.0 -1.0 -1.8 -0.2 +0.3 +0.2 -0.2 + 1.8 -3.9 +0.9 + 1.1 -1.2 + 1.0 + 1.3 +0.6 -0.1 +0.1 +0.8 +0.7 -1.1 +0.9 -1.5 -1.0 -1.2 -1.7 -1.4 +0.2 — 9 O -0.5 Highest and lowest readings are in italics. Minimum temperatures at the coldest and the wannest points on the bog, Mather, Wis. — From the foregoino; it is obvious that great extremes of temperature occur in any bog, and that there is a wide range in minimum temperature in various portions of the same bog. It has, moreover, been found from the discussion of previous tables that at four selected stations the exposed minimum surface readings were highest at Station 3 and lowest at Station 5, and that at both Stations 3 and 5 the exposed minimum at the 5-incli height registered lower than the one at the surface. Stations 2 and 5 were equally cold, Station 5 being in the cran- berry bog, in an uncultivated section, while Station 2 was immediately outside, in a field of sphagnum moss. The observations at Station 5, although sometimes interrupted by reflowing, are preferable in this comparison with Station 3, because of the location of the station among the vines. Stations 3 and 5, then, may be considered as being the warmest and the coldest places on the bog, and the exposed minimums at these two stations will be discussed in detail; first, between the readings of the surface thermometers at both stations during the season of 1907; second, between the surface minimum at Station 3 and the minimum at the 5-inch height at Station 5 ; and, third, between the last-named readings and the readings of the mini- mum in the shelter at Station 1, which, of course, should be the standard for comparison with otiier stations. (See Tables 5, 5a, 6, 6a, 7, 7a.) The exposed minimums at the surface at Station 3, the thinly vinetl, sanded, and well drained section, were usually higher than those at Station 5, over peat and moss, heavily vined and with poor drainage. (Table 5.) The difference between the readings gradually but irregularly increased from spring to midsummer, after which it decreased until the end of the season. The average diiTerence bv months was as follows: May, 3.3°; June, 5.3°; July, 5.7°; 47 Aupjust, 4.9°; September, 2.9°; October, 0.8°; while thegjreatest dailj' difference in each month was 8.9°, May; 8.8°, June; 9.6°, July; 10.2°, August; 7.1°, September; and 4.3°, October. The daily readings at Station 3 were almost invariably much higher than at Station 5, with the exception of the month of October; and but three times during May, June, and July tlid the instruments at Station 5 register higher than at Station 3. These differences were 0.3° on May 15, 1° on June 26, and 1.6° on July 22. In August and September there were no instances in which the thermometers at Station 5 registered higher than at Station 3, while in October there were ten days. The changed relation between tlie readings in October is imdoubtedly tlue to the fact that frost had entered the sanded soil at Station 3, as well as the peat soil at Station 5; and it is probable, as has been said before, that when once frost enters the soil, its character, whether it be peat or sand, is of little consequence in affecting night temperatures. Moreover, the vegetation at Station 5 was gradually dying out toward the end of the season, while at vStation 3 the conditions changed but little. It is interesting to note that on the coldest day of the entire season, October 28, the temperature at Station 3 was 13.9°, 0.3° lower than at Station 5, 14.2°. In the other months, however, the minimums at the sanded section were several degrees higher than in the uncultivated bog. At Station 5 there were several instances of freezing temperature during the first decade of June, and one on July 2; on that date the exposed minimum at the surface of Station 5 registering 30°, while at the surface at Station 3 the reading was 38.8°. Wlienever the readings of the instruments were seriously affected by reflowino- to ward off frost, a pi'oper explanation has been made in the tables, and the values of the readmgs estimated. It is unfortunate that on September 22, 25, and 26 actual readings of the instru- ments at Station 3 were not available, as the portion of the bog in which that station was located was covered with water. In Table 5a will be found the niontldy antl the seasonal averages for the exposed minimums at the surface of Stations 3 and 5. A still further comparison is made in Tables 6 and 6a, showing the difference in readings between the surface thermometer at Station 3 and the thermometer at 5 inches at Station 5. These may be accepted as being approximately the extremes of minimum temperature to which the vegetation in the bog is subjected. The surface minimum at Station 3 averaged higher than any other minimum exposed in the open, while the thermometer at 5 inches at Station 5 averaged the lowest. The average and extreme differences between these instruments were, of course, even greater than those noted in the discussion of Table 5. The average seasonal difference was 4.4°, and the greatest average monthly difference was 7° in June, while the least monthly differences were 3.2° and 3.8° in May and October, respectively. The greatest daily difference in May was 7°; in June, 11.9°; July, 11°; August, 12.8°; September, 10.6°; and in October, 9°. There were but five instances throughout the entire season when the daily minimum at the surface of Station 3 was lower than the upper thermometer at Station 5. The lowest reading hi May at the surface at Station 3 was 21.1°, while at 5 inches at Station 5 on the same day the reading was 17°; in the other months the lowest readings were respectively as follows: June, 33.8° (estimated), and 26.2°; July, 38.8° and 27.9°; August, 42.5° and 33°; September, 24.5° and 16.6°; and in October, 13.9° and 6.4°. 51936°— Bull. T— 10 4 48 Table 5. — Comparison of Minimum Temperatures in Open at the Surfaces of Stations 3 and 5, \mth Differ- ences. Mather, Wis., 1907. May.o 1 June. July. Station 3. Station 5. Difference. Station 3. Station 5. DiSerence. Station 3. Station 5. Difference. 1 - - » - 34.0 38.3 52.9 43.0 44.1 '33.8 49.5 36.1 42.4 53.7 44.0 53.1 42.6 39.3 42.9 53.5 86.6 57.7 56.3 51.0 49.3 62.3 60.3 54.9 58.9 49.0 44.0 45.0 50.0 55.4 30.9 29.6 48.0 35.5 42.0 28.6 45.2 SS.I 34.8 52.7 42.7 51.0 33.8 31.0 41.0 45.9 60. S .50.4 47.8 44.0 43.8 59.4 56.5 50.4 56.1 50.0 36.8 37.1 42.3 49.0 -3.1 — S. 7 -4.9 —7.5 -2.1 -5.1 -4.3 -S.O -7.6 -1.0 -1.3 -2.1 -8.8 -8.3 -1.9 -7.6 -6. 4 -7.3 -8.5 -7.0 -5.5 -2.9 -3.8 -4.5 -2.8 +1.0 -7.2 -7.9 -6.4 59.5 S8.S 47.2 51.5 58.2 57.9 50.5 54.4 58.8 50.0 02.0 49.6 52.9 61.0 88.9 54.0 53.3 51.2 56.9 58.1 ■ 65.9 ■:63.8 55.0 62.2 54.9 52.8 47.5 58.1 58.0 50.3 57.4 56.0 SO.O 40.9 46.3 58.0 53.0 45.0 48.2 51.5 43.0 61.3 43.2 46.8 57.0 86. B 47.1 46.7 43.7 51.3 71.0 60.2 ■165.4 C47.0 <:58.2 C46.8 C43.2 C39.2 54.0 51.0 43.0 50.4 -3.5 2 -8.8 -6.3 4 -5.2 -0.2 5 -4.9 7 -5.5 8 9 : 10 -6.2 -7.3 -7.0 -0.7 12 13 37.3 68.5 46.8 39.0 .36. 9 39.0 41.9 35.0 23.7 11. 1 44.9 45.0 42.1 45.0 46.0 m (*■) 35.9 43.0 48.3 33.9 SB. 8 45.2 39.3 36.1 32.4 34.0 33.1 IS. 8 18.3 40.8 43.8 33.2 45.0 45.4 C) 33.0 38.4 46.7 -3.4 -3.7 -1.6 +0.3 -0.8 -6.0 -7.9 -1.9 -6.9 -2.8 -4.1 -1.2 -8.9 0.0 -0.6 -6.4 -6.2 14 -4.0 16 -6.9 17 -6.6 IS .- 19 -7.5 -5.6 20 -7.1 21 -5.7 22 +1.8 23 -8.0 24 -4.0 25 -8.1 26 -9.6 -8.3 28 -4.1 29 -2.9 -4.6 -1.6 -7.0 30 - -7.3 31 -7.0 Means 40.4 37.1 -3.3 48.8 43.5 -5.3 55.5 49.8 i -5.7 1 ■ o Means for eighteen days. ^ Estimated; actual readings valueless on account of reflowing. b Readings not obtained; marsh flooded. d Affected by water. Station 3. Newly sanded, thinly Tined. ' Station 5. Feat with moss, heavily vined. Highest and lowest readings are in italics. 49 Table 5. — CoMPAmso>j op Minimi:m Temperatures in Open at Surfaces op Stations :^ and .5, with Differ- ences, Mather, Wis.. 1907 — Continued. Dav of month. August. Station 3. Station 5. I Difference. 1 2 3 4 5 6 7 8.." 9 10 n 12 13 14 13 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 Means 55.1 50.9 49.0 42.2 47.1 43.0 43.1 .35.0 r,1.3 ' 58.0 53. 46.2 59.0 55.0 56.6 52.0 54.0 49.6 59.8 54.0 68.7 66.0 49.7 43.0 48.9 43.0 52.3 46.3 56.6 50.6 62.1 59.0 51.2 44.5 54.8 50.0 05.5 65.0 46. ft .37.9 48.4 .38.2 |S.o 38.0 54.0 48.1 50.7 46.1 42.7 36.8 49.8 43. S 57.2 .57.0 54.0 52.1 50.7 46,0 62.9 62.1 56.3 54.2 - 4.2 - 6.8 - 4.1 - 8.1 - 2.7 - 6.8 - 4.0 - 4.0 - 4.4 - 5.8 - 2.7 - 6.7 - 5.9 - 6.0 - 6.0 - 3.1 - 6.7 - 4.8 - 0.5 - 8.7 -10.3 - 4.5 - 5.9 - 4.6 - 5.9 - 6.0 - O.S - 1.9 - 4.7 - O.S - 2.1 September. Station 3. Station 5. Difference. 1 Station i Station 5. Difference. 4.9 64.1 53.9 48.8 52.7 46.7 41.2 56.5 57.2 39.0 "37.0 43.7 43.3 45.7 56.5 57.7 es.i 51.0 59.0 60.4 59.4 ,37.4 O30.3 41.7 44.0 27.2 <"33.0 32.7 38.4 30.0 U.5 October. 61.4 46.8 43.3 48.8 42.0 36.0 55.6 56.2 36.6 "34.1 39.2 40.0 42.8 55.0 54.3 6i.S 46.5 58.6 59.5 58.0 .3.5.2 24.7 41.3 43.3 24.8 20.7 28.8 38.0 26.5 -2.7 -7.1 -5.5 -3.9 -4.7 -5.2 -0.9 -1.0 -2.4 -2.9 -4.5 -3.3 -2.9 -1.5 -3.4 -0.6 -4.5 -O.i -0.9 -1.4 -2.2 -5.6 -O.i -0.7 -2.4 -6.3 -3.9 -O.i -3.5 -3.2 o o 30.8 28.5 -2.3 46.1 47./ +1.0 41.6 38.3 -3.3 .33.6 32.0 -3.5 36.3 32.0 -i.3 38.7 37.0 -1.7 42.1 39.7 -2.4 21.8 19.5 -2.3 34.6 35.0 + 0.4 28.5 28.5 0.0 30.1 30.3 +0.2 28.4 28.7 +0.3 19.0 18.8 -0.2 17.7 18.4 +0.7 40.7 41.8 +1.1 33.1 31.8 -1.3 .30.8 30.5 -0.3 23.6 25.4 +1.8 19.7 18.8 -0.9 26.3 27.0 +1.3 17.5 14.6 -3.1 28.5 27.3 -1.2 24.5 21.8 -2.7 21.3 20.5 -0.8 23.6 23.5 -0.1 16.8 14.7 -2.1 32.3 32.0 -0.3 13.9 H.i +0.3 24.6 24.4 -0.2 36.2 35.9 -0.3 ;t 1 II 30.6 +0.6 2s. » 28.0 -O.S T.\IiLE -Ji;. — MoN'THLV ANI> SEASONAL MeANS, St.ITION'S i? AND 7>. M.\THER, \Vl.«., 1907. May.6 June. July. August. September. October. Seasonal means. Surface: Station 3 40.4 37.1 o 48.8 43.5 « 55.5 49.8 53.7 48.8 45.9 43.0 28.8 28.0 45.5 Station 5 41 7 Difference - 3.3 - 5.3 - 5.7 - 4.9 - 2.9 - 0.8 3.S a Estimated; actual readings valueless on account of reflowing. b Means for eiphteen days. .Stations. Newly sanded, thinly vined. Stations. Peat with moss, heavily vined. Highest and lowest readings are in italics. 50 Table 6. — Comparison of Minimum Temperatures in Open at Surface of Station 3, and at 5 Inch^ at Sta- tion 5, THE Warmest and Coldest Places on the Marsh, Respectively; also Daily Difference.'!, Mather, Wis., 1907. May.o June. July. Day of month. Station 3— surface. Station 5— 5 inclies. DiflEer- ence. Station 3— surface. Station 5— 5 inches. Differ- ence. Station 3— surface. Station 5— 5 inclies. Differ- ence. o „ „ * o „ o o . 1 34.0 38.3 52.9 43.0 44.1 l>33.8 49.5 36.1 42.4 53.7 44.0 53.1 m.2 27.9 46.9 35.0 41.5 l'26.S 43.8 26.5 30.5 53.0 38.4 51.0 - 7.8 -10.4 - 6.0 - 8.0 - 2.6 - 7.0 - 5.7 - 9.6 -11.9 - 0.7 - 5.0 - 2.1 59.5 38. 8 47.2 51.5 58.2 57.9 50.5 54.4 58.8 50.0 62.0 49.6 55.9 gr.9 36.2 43.9 59.7 52.0 42.5 49.4 51.9 41.0 00.1 39.9 - 3.6 -10.9 3 .... _ . . . -11.0 - 7.6 + 1.5 6 . . - . . .... - 5.9 7 - 8.0 s — 5.0 q . - 6.9 in 1 - 9.0 11 1 .. — 1.9 12 37. :i 35.0 -2.3 - 9.7 13 5G.5 58.9 +2.4 42.6 32.4 -10.2 52.9 44.0 - 8.9 14 46. S 45.1 -1.7 39.3 29.6 - 9.7 61.0 56.8 - 4.2 15 39.0 36.9 -2.1 42.9 34.0 -8.9 68.9 67.1 - 1.8 16 36.9 34.8 -2.1 53.5 45.5 -8.0 54.0 45.3 - 8.7 17 - 39.0 33.0 -6.0 6S.S 6S.S - 4.1 53.3 45.0 - 8.3 18 41.9 39.1 -2.8 57.7 48.9 - 8.8 51.2 42.6 - 8.6 19 35.0 2.3.7 31.0 19.3 -4.0 -4.4 56.3 51.0 48.7 42.4 - 7.6 - 8.6 56.9 58.1 51.0 51.3 - 5.9 20 - 6.8 21 .'/.; n.o -4.1 49.3 40.3 - 9.0 65.9 59.9 - 6.0 22 44.9 42.0 -2.9 62.3 59.0 - 2.7 663.8 61.9 - 1.9 23 45.0 43.7 -1.3 60.3 55.2 - 5.1 55.0 i>45.9 - 9.1 24 42.1 34.0 -8.1 54.9 49.5 - 5.4 62.2 1.57.1 - 5.1 25 45.0 43.8 -1.2 58.9 53.1 - 5.8 54.9 645.7 — 9.2 26 46.0 45.0 -1.0 49.0 45.7 - 3.3 52.8 6 42.1 -10.7 27 (') (.') 44.0 34.0 -10.0 47.5 40.0 - 7.5 28 (<■) W 45.0 35.2 - 9.8 58.1 53.2 - 4.9 29 35.9 43.0 48.3 29.3 36.0 45.9 -6.6 -7.0 -2.4 50.0 56.4 . 41.1 47.4 - 8.9 - 8.0 58.0 50.3 57.4 51.5 41.6 50.0 - 0.5 30 - 8.7 31 - 7.4 40.4 37.2 -3.2 48.8 41.8 - 7.0 55.5 48.8 - 6.7 a Means for eighteen days. 6 Estimated; actual readings valueless, on account of reflowing or heavy rains. c Readings not obtained; marsh flooded. Station 3. Xewly sanded, thinly vined. Station 5. Peat with moss, heavily vined. Highest and lowest readings are in italics. 51 Table 6. — Comparison of Minimum Temperatures in Open at Surface of Station 3, and at 5 Inches at Station 5, the Warmest and Coldest Places on the Marsh, Respectively; also Daily Differences, Mather. Wis., 1907 — Continued. Dav of month. August. September. Station 3- j surface. 1 2 3 4 5 0. 7 8 9 lU 11 12 13 14 15 Id 17 18 19 20 21 22 23 24 •25 20 27 28 29 30 31 Means. 55.1 49.0 47.1 43.1 61.3 53.0 59.0 56.6 54.0 59.8 es.r 49.7 48.9 52.3 50.6 62.1 51.2 54.8 65.5 46.6 48.4 4£.S 54.0 50.7 42.7 49.8 57.2 54.0 .50.7 62.9 56.3 Station 5 — 5 inches. 53.7 44.0 40.9 41.9 S3.0 38.0 44.8 54.0 50.1 48.0 53.0 89.0 41.0 40.6 45.0 50.2 38.6 43.6 46.7 64.8 34.8 35.6 33.6 46.1 44.3 33.3 41.0 55.6 50.5 44.0 62.6 52.7 Differ- ence. -11.1 - 8.1 - 5.2 -10.1 - 3.3 - 8.2 - 3.0 - 6.5 - 6.0 - 6.8 + O.S - 8.7 - 8.3 - 7.3 - 6.4 - 3.5 - 7.6 - 8.1 - 0.7 -11.8 -IS. 8 - 8.9 - 7.9 - 6.4 - 9.4 - 9.8 - 1.6 - 3.5 - 6.7 - 0.3 - 3.6 Station 3- siirface. M. 1 53.9 48.8 32.7 46.7 41.2 56.5 57.2 39.0 "37.0 43.7 43.3 45.7 56. 5 57. 7 65.1 51.0 .59. (JO. 4 59.4 .37.4 "30.3 41.7 44.0 a 27. 2 "3.3.0 32.7 38.4 30.0 Station .5- 5 inches. 61.7 43.5 41.3 48. 8 41.3 32.6 35.5 "50.8 33.7 " 32. 3 36.5 37.0 39.7 .54.9 53.0 64.5 43.5 56.1 68. S 56.2 31.1 19.7 39.0 41.7 20.0 22. 6 20.1 36.9 23.3 16. 6 47.1 6, 6 Differ- ence. -2.4 -8.4 - 7. 5 -3.9 -5.4 -8.6 - 1.0 - 6.4 -5.3 -4.7 - 7. 2 - 6.3 -6.0 - 1.6 -4.7 -0.6 - 7.5 -2.9 - i.e -3.2 -6.3 -10.6 -2.7 -2.3 - 0.6 -10.4 -6.6 -1.5 -6.7 -7.9 - 5.2 October. Station 3- snrface. 30.8 46.1 41.6 33.5 36. 3 38.7 iJ.O 21.8 34.6 28.5 30.1 28.4 19.0 17.7 40.7 33.1 30.8 23.6 19.7 26.3 17.5 28. 5 24.5 21.3 23. 6 16.8 32.3 13.9 24.6 36.2 30.0 Station 5- 5 inches. 28.8 25.6 46.7 35.5 29.3 30.3 35.6 38.0 12.8 34.0 24.8 28.3 25.9 12.0 12.4 il.S 29.4 28.4 20.7 13. S 23.5 9.8 26.5 18.8 14.7 21.5 9.3 31.6 6.4 21.7 35.7 29.5 25.0 Differ- ence. -5.2 +0.6 -6.1 -4.0 -6.0 -.3.1 -4.0 -9.0 -0.6 -3.7 -1.8 -2.5 -7.0 -5.3 +0.8 -3.7 -2.4 -2-9 -5-9 -2.8 -7.7 -2.0 -5-7 -6.0 -2.1 —7.5 -0-7 -7.5 -2.9 -05 -0-5 -3.8 Table (in. — Monthly and Seasonal Mean.s. St.4.tion 3, Surface, and St.\tion 5, 5 Inches. Mather. Wis. 1907. Ma.v.l> 40.4 37.2 June. .Tuly. .Vugnst. September. October. Seasonal means. 48.8 41.8 55.3 48.8 53.7 47.1 45.9 40.7 28.8 25.0 45.3 40.1 Station 5 — 5 inches . Diflerence -3.2 -7.0 -6.7 -6.6 - 5.2 - 3.8 - 5.4 " Estimated: actual readings valueless, on account of reflowing or heavy rains. b Means for eighteen days. Station 3. Xewly sanded, thinly vined. Station 5. Peat with moss, heavily vined. Highest and lowest n-adings are in italics. 52 Comparison of minimum temperatures at Station 1 , in sJielter, and on hog at Stations S and 3, Mather, Wis. — While the comparisons made in Tables 5 ami 6 have been between the warmo>st and the coldest stations on the bog, the tejuperature in the shelter at Station 1 on the upland may properly be considered the standard, and a comparison between the thermometer therein and one in the open at the height of 5 inches at Station 5 and tlie one at the surface at Station 3 should be of special interest. Of course, the exposed minimum at Station 5 was much lower than the one' in the shelter at Station 1, the average difference being 6.7°. (See Tables 7 and 7a.) The least monthly average difl'erence was 4.5° in May, and the greatest 8. .3°, in October. The greatest daily difference in May was 12° on the 29th; in June, 11° on the 27th; in July, 12° on the 3d; in August, 14.2° on the 25th; in September, 1 1.6° on the 22d; in October, 14.6° on the 24th. With but few exception the temperature at Station 5 was lower than at -Station 1 and markedly so on clear, cool nights. When the sky was overcast and the night windy the difference was much less. The comparison between the shelter at Station 1 and the surface at Station 3, however, aft'ords far different results. The temperature at Station 3 was, as a rule, only slightly below that in tlie shelter at Station 1 , the seasonal average difference being 1 .3°. In the summer the differ- ence was very little, being only 0.1° and 0.2°, but it was greater in the spring and in the fall, espe- cially in October when the average tlifference was 4.5°. At Station 5, as has been statetl before, the difference was 8.3° for October. It is probable that these great differences in October were due to the number of comparatively cool nights which were gradually increasing in length and which affortled a longer period for radiation and consecjuent loss of heat from vegetation. The daily differences between the readings in the shelter at Station 1 and those in the open at Station 3, the sanded section, were often unimportant, and on many tiays tiiere was a reversal, the tem- perature aetually reading higher over the sanded section in the hog, especially in the summer motiths. This inversion occurred on fourteen days in June, fourteen days in July, fifteen days in August, ten days in September, hut in no instance in October. These results — the comparatively high miniuuim temperatures at the surface of the sanded bog — realty seem remarkable, and could hardly be believed unless great care iiad been taken in the observations. In this connection it is interesting to note that the mininuim temperature in tlie shelter at Station 3 averageil for the season only 0.5° below that in the shelter at Station 1, while the minimiun in the shelter at Station 5 averaged 3.1° below that in the shelter at Station 1. (See Table 18.) The advan- tages gained by sanding are still further emphasized by observations made at Berlin, Wis., where the exposed minimum at the surface of a sanded section during the montii of Se])tember, 1906, actually averaged higher by 0.5° than the minimum in the shelter at Station 1 , on adjoining hard land, while the exposed minimum at the 5-inch height at Station 5, the coldest point on the Berlin bog, averaged 9.5° lower than that in the shelter at Station 1. (Table 9.) From the comparison of these observations made at Stations 3 and 5, at Mather, it should be apparent that a thinly vined, sanded, and well drained soil is a most important factor in conserving heat — in strong contrast with a heavily vined moss-covered surface which absorbs but little heat, and at the same time radiates rapidly. 53 Table 7.— Comparison of Min'1.uum Temperatures in Shelter at Station 1, and in Open at 5-inch Height at Station 5, the Coldest Place on the Marsh, and in Open .at Surface at Station 3, the Warmest Place on the Marsh, Illustrating the Advantages obtained from Sanding, Draining, and Cultivating, Mather, Wis., 1907. May. June. Day of month. Station 1— shelter. Station 5— 5 inclies above sur- face ex- posed. Difference. Station 3— .surface exposed. DiSer- ence— Stations 1 and S. Station 1— shelter. Station 5— 5 inches above sur- face ex- posed. j Difference. Station 3- surface \ exposed. Differ- ence — Stations 1 and 3. = - ' = ' 36.0 38.7 50.1 41.2 44.4 SJ,.0 47.6 36.0 41.0 54.5 47.0 52.8 43.7 38.9 43.0 53.8 70.0 58.6 57.0 50.6 48.7 61.4 60.2 54.0 57.8 48.2 45.0 43.0 51.0 58.0 26.2 27.9 46.9 35.0 41.5 32.5 43.8 26.5 30.5 63.0 38.4 51.0 32.4 29.6 34.0 45.5 62.5 48.9 48.7 42.4 40.3 59.6 55.2 49.5 63.1 45.7 34.0 35.2 41.4 47.4 - 9.8 -10.8 - 8.2 - 6.2 - 2.9 -US - 3.8 - 9.5 -10.5 - 1.5 - 8.6 - 1.8 -11.3 - 9.3 - 9.0 - 8.3 - 7.5 - 9.7 - 8.3 - 8.2 - 8.4 - 1.8 - 5.0 - 4.5 - 4.7 - 2.5 -II. - 7.8 - 9.6 -10.6 4.0 38.3 52.9 43.0 44.1 SS.8 49.5 36.1 42.4 63.7 44.0 53.1 42.6 39.3 42.9 53.5 66.6 57.7 56.3 51.0 49.3 62.3 60.3 54.9 58.9 49.0 44.0 45.0 50.0 55.4 - 2.0 - 0.4 - 2.2 -1- 1.8 - 0.3 - 0.2 "_ + 1.9 -1-0.1 '. -1-1.4 A - 0.8 -3.0 12 36.2 610 44.7 36.0 35.0 40.0 47.7 38.8 27.5 er.s 45.0 44.0 43.6 45.0 43.3 ^&^5=>^'^ 1 L S,. , < "f 1 => ^ c c_ i) ^ 5fc» C~ CI \ "'s. K "* -^— ^ -^ U ^V-^ t^ Ci c> li^ ^ r^ :N _>- J y <^ — s.- c — ' r \ ^ < cr-/ 1 ^ :^J ■^jn-~ s c- <;' ^ ■^ ■^ ^ ti 'r, 'il c~~ k ^^ ^ ^ 0^ '^^ S '^ ^ ^ $ << vi ^- ^^ - C >• ^- 1 tis ^ s - :^^-. v.. • c =, ^, ^ -ft < to ^ 5^ 1^ -7^~^'. 5 •i^ P >)' ^ -> c ^:i X ^ -? k 1 1 1 1 r- 1 ■^ ^ 1 ! 1 1 ^ ^-^^r' S (^ -C; < -1^ •*^ ^ '"-. =^ ^ ^ ^ ^. s <^ >0 tV) >o 5 V ^ ^ ^ T% ^ S 5> ~ ! '■ 1 1 5^ (I, It 1 ^ c ^ " — ^ ■" ■o ^ '? •^:^ <^^ 4 C -^A ■~^ ' 0. n- ^ Q- r* -^ ^ \ ■^ \ ^ ^o ^ ^ L f s ^ ^ ^' .J;-. ,> r ^ V ^ § [^> > '. r ; ^ ', z'' ■ ? c** \ ~-<:i > . ^/ \ \ ^ \ ::=:^ \ ■•'. C --^ 1 c- J^i /\ Cvi ^ . IL^ ^nj^j^ ■^.•, From a study of the graph, as showiwin Figure 21, it is extremely interesting to note the tend- ency of the soil temperature during tlie months of August and September at the 3-inch dejith at Station 5 to fall below that at the 6-inch depth at the same station, and it was noted to be actualh' lower for the first time on September 5. From the 20tli on the readings at the former depth were almost continuously below those at the latter depth. In fact, by referring to Table 19, it will l)e found that tiie soil temperature at 6 inches at Station 5 began to gain on the temperature at 3 inches at the same station as early as July, and by the following amounts: Juty, 0.6°; August, 0.8°; September, 1.2°; Octo- ber, 1.3°. This is because after a certain date, apparently late in July, the temperature of the soil at 3 inches began to decrease while that at 6 inches began to decrease also, but more slow- ly; so that during the month of October the temperature at the 6-inch depth was usually higher than at the 3-inch depth. This shows that while the peat soil at 6 inches under a thick growth of vegetation takes a longer time to become heated than at the three other locations, it retains its heat longer. The reason that gen- erally during October the soil temperature at 3 inches at Station 5 was the lowest of the four exposures, with the readings at 6 inches be- tween it and the 3-inch depth at .Station 3, was probably because that, although it was not as easily influenced by the insolation as that at vStation 3, still the temperature at 3 inches at Station 5 was not nearly as high even in mid- summer, so that when cool weather approached it remained relatively low. On the other hand, tlie temperature at 3 inches at Station 3 was lower during cool, cloudy weather, and warmer during warm, sunshiny days; at the same time the temperatures at 6 inches took intermediate values because of their greater depth and conse- quent slower changes. Minimum tem-peratures at the coldest and the warmest points on the hog at Berlin, Wis. — It is po,ssible to make a comparison between the read- ings of the minimum thermometers exposed in the bog at places at Berlin, that are considered the warmest and the coldest referred to in pre- vious paragraphs, and also to compare these readings with the readings of a thermometer in a shelter on hard land on the edge of the bog. The readings are found in Tables S and 9, and, although given only for the month of Sep- tember, 1906, will serve to supplement the Mather 59 observations. Station 3 at Berlin was located in a newly sanded, thinly vined, and well drained section, similar to Station 3 at Mather, while Station 5 at Berlin was in the midst of a dense growth of vegetation, includmg vines, grasses, canebrakes, and ferns. In fact, this station was commonly called the "ferns." The uprights from the vines reached to a height of from 12 to 18 inches. It was a wild place, not resembling the conditions one would expect to find in a cultivated cranberry marsh; but cultivation was not practiced in reality at Berlin. Although it was the coldest point in the Berlin bog, the vegetation there was not similar to that prevailing at Station .5 at Matlier. Wliile moss, which is largely responsible for low night temperatures, was found at Mather, there was no indication of it whatever at Berlm, but the rank growth of vines and grasses because of generally poor cultivation was a fitting substitute. It is not intended to make any detailed comparison between the readings of the thermom- eters at Stations 3 and 5 at Berlin at corresponding positions, but to compare the readings at the surface at Station 3 with those at the 5-inch height at Station 5, the warmest and the coldest exposures on the bog. However, in Table S are fu'st given the readings of the mininnim thermometers at both the surface and 5 inches, and the differences between the readings at each station; and in the lower column, are given the differences between the readings at the surface at .Station 3 and the 5-inch height at Station 5. It is proper to state that the upper thermom- eter at Station 5 was not attached to any support, but was placed upon the vegetation which had been pressed down to a compact mass so that the thermometer rested 5 inches above the surface of the soil near the surface instruments. The lower thermometer was not shielded in the slightest degree by the upper one, but the radiation was freer at the higher elevation than from the lower thermometer which was obstructed laterally and obliquely by the dense vege- tation. At Station 3 the liigher thermometer was fastened to a post immediately above the thermometer which lay upon the ground. The average difference for the month between the surface thermometer at Station 3 and the upper thermometer at Station 5 was 10°, and the maximum daily difference was 17.1° on the 4th. On .only one day during the month was there an inversion of the usual conditions, September 2, and this was because there was water on tlie thermometers after a heavy rain. In fact, the readmgs of the instruments on that day should properly be excluded. These differ- ences in temperature at Berlin were even greater than those observed at Mather. The minimum thermometer in the shelter at Station 1 at Berlin, which was located on the edge of the bog, may be considered the standard as was that at Station 1 at Mather, and a comparison between the warmest and the coldest points on the bog at Berlin with this standard is important. For the month of September, 1906, the upper exposed thermometer at Station 5 averaged 9.5° below that in the shelter at Station 1, while a maximum difference of 16.4° occurred on September 3, and on sixteen days there were differences exceeding 10°. (Table 9.) In comparing the surface readings at Station 3 with the standard, it will be found that the exposetl minimum over the sanded section actually averaged for the month higher by 0.5°. It, moreover, was higher on eighteen days, whOe on tlu-ee days the readings were tlie same. These results indicate the great advantage gained in draining, cultivating, and sanding a bog. In spite of the fact that the thermometer at Station 3 urns exposed at the surface of the soil in the open where the radiation was perfectly free, it averaged higher than the one in the shelter on hard land. The conditions at Station 3 resemble approximately the improved conditions found in the Cape Cod marshes, while those at Station 5, on the other hand, are representative of the poorest conditions found in Wisconsin. It wouhl seem as a result of these observations that the Wis- consin growers should feel obligetl to adopt the Massachusetts methods. 60 Table 8.— Minimum Temperatures in the Open at Surface and at 5-Inch Height with Diffeminces, for Station 3, Heavily Sanded, Thinly Vined, and Station 5, Peat, Heavily Vined, Dense Groi^v^ op Vege- tation and Ferns, the Warmest and Coldest Parts of the Marsh, Respectively; Also Difference Between Surface, Station 3, and 5-Inch Height, Station 5, Berlin, Wis., September, 1900. Ii Station 3. Station 5. Difference- Station 3. Day of month. Surface. 5 inches. Difference. Surface. 5 Inches. Difference. surface, and Station 8, 5 inches. o , o o o o o I 51.5 45.5 -6.0 40.2 38.7 -1.5 -12.8 , 58.2 52.0 59.0 43.5 +0.S -8.5 aes.o 37.0 35.0 4-0.1 -2.0 + 4-9 3 - -17.0 4 51.0 45.0 52.0 55.0 56.8 41.5 35.9 42.9 50.0 54.9 60.0 64. e -9.5 -9.1 -9.1 -5.0 -4.1 37.5 32.0 39.8 47.4 49.0 33.9 28.3 36.0 44.0 46.2 -3.6 -3.7 -3.8 -3.4 -2.8 -n.i -16.7 -16.0 -11.0 8 -10.6 9 59.0 64.5 68.0 -4.1 -4.5 -1.4 52.0 56.0 60.0 49.7 54.0 60.7 -2.3 -2.0 +0.7 - 9.3 -10.5 11 - 5.3 12 63.9 59.5 -4.4 56.6 54.8 -1.8 - 9.1 13 53.9 52.8 -1.1 52.3 50.8 -1.5 - 3.1 14 43.9 35.0 -8.9 32.6 28.8 -S.S -15.1 15 48.1 44.7 -3.4 42.8 41.0 -1.8 - 7.1 16 56.0 55.4 -0.6 53.9 52.8 -1.1 - 3.2 17 - 62.3 59.0 -3.3 56.0 54.4 -1.6 - 7.9 18 64.0 60.0 -4.0 55.8 55.8 0.0 - S.2 19 - 60.0 68.1 -1.9 52.9 52.0 -0.9 - .8.0 20 ■--■ 60.0 58.0 -2.0 58.0 57.5 -0.5 - 2.5 21 60.0 51.3 -5.7 50.9 49.0 -1.9 -11.0 22. 55.1 50.4 41.0 48.5 45.0 34.0 -6.6 -5.4 -7.0 45.8 • 42.4 31.8 42.1 38.9 28.9 -3.7 -3.5 -2.9 -13.0 23 -11.5 24 -12.1 25 45.0 54.8 40.0 53.8 -5.0 ,-1.0 38.0 50.0 34.3 48.9 -3.7 -1.1 -10.7 26 - - 5.9 27 ■ . 40.3 43.0 54.3 39. e SO.S 35.7 53.5 31.0 -9.5 -8.3 -0.8 -8.6 28.0 31.5 53.6 sr.e 24.4 28.0 53.6 23.0 -3.6 -3.5 -0.6 -3.7 -15.9 28 -15.0 29 - 1.3 30. —16.6 Means .. , . 53.6 48.7 -4.9 45.8 43.6 —2.2 -10.0 a Water on thermometers, and grass and vines very wet. due to rain. Highest and lowest readings are in italics. 61 Table 9. — Comparison of Minimum Temperatures in Shelter, Station 1, and in the Open at 5-inch Height AT Station 5, Peat and Heavily Vined, and at Surface at Station 3, Thinly Vined and Newly Sanded, Berlin, Wis., September, 1906. Day of month. Station 1— Shel- ter. Station 5-5 inches exposed. Differ- ence. Station 3— Sur- face ex- IMsed. Differ- ence — Stations 1 and 3. Day of month. Station 1— Shel- ter. Station 5—5 Inches exposed. Differ- ence. Station 3— Sur- face ex- posed. Differ- ence- Stations 1 and 3. 1 50.0 65.7 51.4 46.8 42.0 47.6 56.0 57.4 56.1 64.5 69.0 62.9 54.0 41.3 51.9 57.9 38.7 "es.i 35.0 33.9 28.3 36.0 44.0 46.2 49.7 54.0 60.7 54.8 50.8 28.8 41.0 52.8 -11.3 - 2.6 -16.4 -12.9 -13.7 -11.6 -12.0 -11.2 - 6.4 -10.5 - 8.3 - 8.1 - 3.2 -12.5 -10.9 - 5.1 51.5 58.2 52.0 51.0 46.0 52.0 55.0 56.8 59.0 64.5 66.0 63.9 53.9 43.9 48.1 56.0 -fl.5 -7.5 +0.6 -1-4.2 -fS.O +6.6 -1.0 -0.6 +3.1 -3.0 -t-1.0 -0.1 -1-1.4 -3.8 -1.9 17 62.0 64.0 60.0 5S.6 59.0 53.9 50.3 38.4 47.0 56.4 S6.0 41.1 53.9 38.0 54.4 55.8 52.0 57.5 49.0 42.1 38.9 28.9 34.3 48.9 24.4 28.0 53.0 SS.O - 7.6 - 8.2 - 8.0 - 1.1 -10.0 -11.8 -11.4 - 9.5 -12.7 - 7.5 -11.6 -13.1 - 0.9 -15.0 62.3 64.0 60.0 60.0 60.0 55.1 50.4 41.0 45.0 54.8 40.3 43.0 54.3 S9.e -(-0.3 9 18 3 19 20 21..... 22 24. 25 20 27 28 29 30 Means 4 -1-1.4 5^ 4-1.0 6 -1-1.2 7... -1-0.1 8 -f3.4 9 -2.0 10 -1.6 11 -1-4.3 12 -t-1.9 13 -1-0.4 14 -1-1.6 53.1 43.6 - 9.5 53.6 16 -1-0.5 a Water on thermometer, and grass and vines very wet, due to rain. Highest and lowest readings are in italics. Minimum temperatures over dry and moist sand, Stations 3 and 4. Berlin, Wis. — In order to further supplement the extensive observations made at Mather, a comparison was made between the surface ininimum thermometers at Berlin, at Stations 3 and 4, tlry and wet sand, for Septem- ber, 1906. This comparison was made because data of the kind desired were not available at Mather, the sanded sections there being all comparatively dry. Both these stations were located in the thinly vined section, and there w^as apparently no difl'erence in the character of the two stations, except that one was much wetter than the other. (See Table 10.) The temperature at the surface at Station 4 averaged 2.4° lower than that at the surface at Station 3, and there was an extreme difference* of 7.3° on September 30, when the thermometer at Station 3 regis- tered 39.6°, and the one at Station 4, 32.3°. On the folloiving day, October 1 (not included in this table), the minimum at Station 3 registered 35.8°, and at Station 4, 27.3°, the difference being 8.5°. It was on this date that the berries were frozen generally in the bog except in the dry sanded section. On only one tlay did the thermometer at Station 3 register lower than the one at Station 4. The increased amount of moisture at Station 4 is solely responsible for the rela- tively low temperature readings, on account of the heat lost in the evaporation at the surface. Wliile the reading of 64° on September 2 is included in the table and in the averages, it is not consistent with the other readings, and was due to w'ater on the bulb of the instrument after a heavy rain. Table 10. — Minimum Temperatures in the Open at Surfaces of Stations 3 and 4, with Differences, Berlin Wis., September, 1906. Day of month. 3- 4. 5. 6. 7. 8. 9. 10. 11.. Station Station Differ- 3. 4. ence. . i . 51.5 47.8 -3.7 58.2 O64.0 -1-5. « 52.0 48.0 -4.0 51.0 48.0 -3.0 45.0 43.2 -1.8 52.0 48.1 -3.9 55.0 52.1 -2.9 56.8 56.0 -0.8 59.2 59.4 4-0.2 64.5 64.3 -0.2 66.0 66.0 -1.0 Day of month. Station 3. 12 63.9 53.9 43.9 48.1 56.0 62.3 64.0 60.0 60.0 13 14 15 16 17 18 19 20 21 60.0 22 55.1 Station 4. 62.1 53.0 37.7 47.0 56.5 60.8 63.0 57.9 59.0 .56.1 51.3 Differ- ence. -1.8 -0.9 -6.2 -1.1 -1-0.5 -1.5 -1.0 -2.1 -1.0 -3.9 -3.8 Day of month. Means . Station 3. Station 4. o o 50.4 47.1 41.0 37.4 45.0 42.7 54.8 52.8 40.3 33.1 43.0 38.0 54.3 53.4 S9.6 SB.S 53.6 51.2 Differ- ence. -3.3 -3.6 -2.3 -2.0 -7.2 -5.0 -0.9 -7.S a Water on thermometer, and grass and vines very wet, due to rain. Both stations thinly vined and lieavily sanded, but Station 3, dry sand, and Station 4, wet sand. Highest and lowest readings are in italics. 62 Minimum temperatures over peat hogs, heavily rined and thinly inned, Berlin, Wis., ^eptemher, jgog^ — In Tables 8 and 9 appear the readings of exposed minimum tliermometers located at Station 5, in the ferns at Berhn, the coldest point in the Berlin bog. As stated above, the vegeta- tion was verj- rank there. Station 2 at Berlin resembled Station 5 in its peat soil and want of good drainage, but it had in the sprng of 1906 been thoroughly weeded, so that the vege- tation was thin. Stations 2 and .5, then, ma}' therefore well represent respectively thinly vined and densely vined locations. The record of the exposed mininnims for September, 1906, ab an elevation of 5 inches above the surface. Table 11, shows that Station 5 averaged .3.4° lower than Station 2. A maximum dilTerence of 6.6° occurred on September 27, and if we exclude the readings of September 2, when water was on the bulb of the thermometer at Station 5, after a heavy rain, there is not a single instance in which the minimum at Station 2 was lower than the one at Station 5. The great differences in temperature are due entirely to weeding, the soil in the thinly vined section during the growing season being much warmer than a soil covered with dense vegetation. Radiation, however, should be just as free from a thinly lined peat soil as from one heavily vined. It is as important to cidtivate as it is to practice drainage. Of course it is impossible to determine absolutely the advantage in exact degrees gained by cultivation, draining, or sanding. While there is an average difference of 3.4°, as shown by Table 11, between the minimum thermometers in the thinly vined and the heavily vined .sections, a difference of 2.4°, as shown by Table 10, between the minimum thermometers on wet and on ilrv sand, a difference of 1.7° between thermometers on peat and sanded bogs, both thinly vined, and a difference of 2.2° 'between the surface and 5 inches, it is obvious mIiv an average difference of 10°, as shown by Table S, can exist between a minimum thermometer exposed at the most favorable location as far os drainage, samling, and cultivating are concerned, and another in a most unfavorable location, an unsanded peat section with a very dense growth of vegetation, and poor drainage. It is not strange, therefore, that in a bog where there is a variation in tiie conditions of sanding, draining, and cultivation, the range in minimum temperature is con- siderable, and that a portion of a bog is .seriously injured by frost, while another portion com- pletely escapes. It should be apparent why the experiment station at Cranmoor, Wis., wliere intensive cranberry growing is practiced, does not require reffowing of its bog on many cold nights in order to escape injury, when the crop of an unimproved liog might be completely wiped out unless protected b_y reflowing. For the same reason, the Cape Cod growers, on account of the excellent condition of their marshes, are seldom forced to use water for protection except in the late autumn. T.\Bi.E 11, — MiN'i.MUM Temperatures in the Open at 5-inch Height, at Stations 2 and .5, with Difference.s Berlin, Wis., September, 1906. Day of month. Station 2—5- inch. Station 5—3- inch. Differ- ence. 1 41.fi 59.3 39.5 38.9 33.1 40.8 47. B 50.0 52.4 57.4 64.0 38.7 1^63.1 35.0 33.9 28.3 30.0 44.0 40.2 49.7 54.0 60.7 -2,9 -1-3. S -4.5 -5.0 -4.8 -4.8 -3.6 -3.8 -2,7 -3.4 -3.3 2 3 4 5 6 7 8 9 10 11 Station Day of month. I 2 — 5- inch. 12. 13, 14. 15, 10, 17. 18, 19 20 21 22 57.4 53.0 33.0 44.5 54.9 57.3 57,6 58,0 58.0 51.4 47,0 Station 5—5- inch. 54.8 50.8 28.8 41.0 52.8 54.4 55.8 52.0 57.5 49.0 42.1 Differ- ence. -2.6 -2.2 -4.2 -3,5 -2.1 -2.9 -1.8 -6.0 -0.5 -2.4 -4.9 Day of month. 23 24 23 26 27 28 29 30 Means Station 2—5- inch. Station 5—5- inch. 43.8 32.5 38,7 52.8 I 31.0 31.9 53,0 i 28.8 j 47.0 38.9 28.9 34,3 48.9 24.4 28.0 53.0 23.0 43.6 Differ- ence. -4.9 -3.6 -4.4 -.3.9 -«.« -3.9 -0,6 -5,8 o Water on thermometer, and grass and vines very wet, due to rain. Station 2. Peat bog, thinly vined. Station 5. Peat bog, heavily vined, with dense growth of vegetation and ferns. Highest and lowest readings are in italics. 63 Minimum temperatures over peat hog and sanded hog, thermometers exposed at 5 inches ahove the surface, at Cranmoor, Mather, and Berlin. — Having made a comparison between the exposed minimums in various portions of the same bog at both Mather and Berhn, it is interesting to note how the readings vary in different bogs, for the season or a portion of the season, when the minimum thermometers are exposed in the vines over different soils at the height of 5 inches above the surface. In Table 12 we have a comparison between Cranmoor," Mather, and Berlin for the months of August and September, 1906, at certain selected stations over peat and sanded bogs. The locations in each marsh were respectively the coldest and the warmest points, although it should be understood that the exposures of the thermometers given were at an elevation of 5 inches above the ground, the minimums, of course, registering higher at the surface where the radiation was less free. The sanded surfaces at the three stations closely resembled each other, while the exposures in the peat bog were over moss at Cranmoor and Mather and in the ferns at Berlm, there being no moss at the latter station. The vegetation was dense, however, in all three peat bogs, it being densest at Berlin. The average daily and the average monthly readings at any particular station are in themselves of little consequence in the discussion of Table 12, as there may be a variation in temperature because of the difference in geographical location. The average readings at corresponding locations at Cranmoor, Mather, and Berlin for the two months did not vary materially, but it is M'ith the differences between the exposed minimums over the peat antl the sanded bogs in which we are especially interested. For the two months the temperature over the sanded bog averaged higher than over the peat, as follows: Cramnoor, 5.3°, Mather, 4.4°, and Berlin 5.4°; the greatest daily difference was 11° at Cranmoor on August 30 and at Mather on September 15, and 19° at Berlin on August 11. At no time did the minimum over the peat register higher than that over the sand at any one of the three stations, with the single exception of September 2 at Berlin, when the instrument in the peat bog was affected by water, after a heavy rain. There were several dates, however, invariably on cloudy nights, when there M-as no difference between the readings of the instruments over the peat and the sand; but, of course, on these nights the temperature was high and there was no danger from frost. In 1907 and 1908 data are available for the season at Cranmoor and Mather only, the Berlin station having been discontinued. It did not seem necessary to publish the tables for these two years. The most important features, however, were as follows: At Cranmoor in 1907 the differences averaged greatest during the summer months of July and August, 6.7° and 6.6°, respectively, while at Mather the greatest average monthly difference was 4.2° in September, this being 0.1° higher than the average for August. The greatest difference at Cranmoor on any one day was 12° on June 27, while the greatest ilifference at Mather was 8° on September 2 and 3 and October 5. In 1908 the average difference was 4.5° at Cranmoor and 4° at Mather, and the greatest difference on any one day occurred on August 5, 1 1 ° at Cranmoor, and at Mather the greatest difference, 8°, occurred on seven different days. " Observations over sanded bog made at Cranmoor Experiment Station and those over peat af the Gaynor- Blackstone marsh immediately adjoining. 51936"— Bull. T— 10 5 64 Table 12.— Minimum Temperatures in Open over Peat Bog with Dense Vegetation, and in "&nes over Sanded Bog, both at the Height of 5 Inches, the Latter Representing Best Results from Sanding, Draining, and Cultivating at Cranmoor. Mather, and Berlin, Wis., August and September, 1906. [P. indicates peat bog; S. indicates sanded surface; Diff. indicates e.xcess of temperature of sanded surface over that of the peat bog.; August, 1906. September, 1906. Day of month. Craamoor. Mather. Berlin. Cranmoor. Mather. Berlin. P. S. DifF. P. S. Difl. P. S. Difl. P. S. Difl. P. S. Diff. P. S. Dill. 1 47 53 55 48 65 46 59 57 63 55 46 47 43 46 45 50 55 59 60 59 64 64 64 69 68 65 33 35 44 SO 34 54 55 61 56 65 53 60 64 65 62 54 50 52 54 53 57 60 61 64 65 68 67 68 60 68 67 S8 42 52 41 44 + 7 + 2 + 6 + 8 + 7 + 1 + 7 + 2 + 7 + 8 + 3 + 9 + 8 + 8 + 7 + 5 + 2 + 4 + 6 + 4 + 3 + 4 + I + 2 + 5 + 7 + 8 +11 +10 55 55 55 48 64 48 58 59 64 60 51 44 47 48 45 51 54 55 58 63 64 64 6e 60 61 62 SI 34 52 36 36 57 57 59 54 64 53 60 62 66 64 57 49 52 53 50 56 59 60 62 67 68 67 69 60 69 63 a 40 ii42 56 42 42 + 2 + 2 + 4 + 6 + 5 + 2 + 3 + 2 + 4 + 6 + 5 + 5 + 5 + 5 + 5 + 5 + 5 + 4 + 4 + 4 + 3 + 4 + 4 + 1 + 9 + 8 + 4 + 6 + 6 45 52 57 50 66 41 56 60 61 55 48 45 39 44 44 49 62 54 58 64 65 60 61 60 66 68 SO 36 48 36 38 56 56 63 52 66 54 62 64 64 63 67 61 45 50 50 57 65 58 58 69 70 64 61 61 67 68 S8 44 52 46 44 +11 + 4 + 6 + 2 +13 + 6 + 4 + 3 + 8 +19 +16 + 6 + 6 + + 8 + 3 + 4 + 5 + 5 + 4 + 1 + 1 + 8 + 8 + 4 +10 + 6 38 61 32 35 32 37 42 47 47 53 58 60 49 28 47 59 58 58 56 54 52 41 37 34 35 40 26 26 51 17 o. o 46 , + 8 61 1 43 . +11 42+7 38 55 35 36 33 36 44 47 48 56 6S 60 48 31 40 58 57 58 50 54 49 44 41 38 38 40 28 31 36 BS 44 64 43 40 40 42 49 53 53 60 66 61 49 34 51 65 60 62 56 55 55 49 46 42 43 42 34 36 39 B8 + 6 + 9 + 8 + 4 + 7 + 6 + 5 + 6 + 5 + 4 + 2 + 1 + 1 + 3 +11 + 1 + 3 + 4 + 6 + / + 6 + 5 + 5 + 4 + 5 + 2 + 6 + 5 + 3 + 3 o 39 6S 35 34 28 36 44 46 50 54 61 55 51 29 41 53 54 56 52 58 49 42 39 29 34 49 24 28 53 BS e 46 59 43 41 36 43 50 53 55 60 66 60 53 35 45 55 59 60 58 58 54 48 45 34 40 54 SI 36 54 SI + 7 2 - 1, 3 + 8 4 '. . + 7 5 41 45 50 52 54 60 6S 6S 51 36 49 59 61 6S 57 55 56 49 45 42 42 43 33 33 54 S9 + 9 + 8 + 8 + 5 + 7 + 7 + 4 + 2 + 2 + 8 + 2 + 3 + 4 + 1 + 1 + 4 + 8 + 8 + 8 + 7 + 3 + 7 + 7 + 3 +12 + 8 + 7 7 : + 6 8 + 7 9 + 5 10 + 6 11 + 4 12 + 5 13 + 2 14 + 6 15 + 4 Ifi ' ■.. + 2 17 + 5 18 19 20 - 21 22 + 4 + 6 + 5 + fl 23 + 6 24 + 5 25 + 6 20 + 5 27 + 7 28 . . . + 8 29 + 1 ,30 + « 31 Means 52.2 57.4 +5.2 53.3 57.3 +4.0 52.2 57.9 +5.7 43.7 49.1 +5.4 43.9 48.7 +4.8 43.6 48.7 +5.1 a Water on thermometer, from rain. Highest and lowest readings are in italics. Table 12a. — Means of Table 12. Cranmoor: Peat bog . Sanded surface.. Difference , Mather: Peat bog Sanded surface . Difference Berlin: Peat bog Sanded surface- Difference Means. 65 Readings of exposed minimurns at various elevations over hog and upland , Stations 2 arul 9, Mather, Wis. — In the preceding pages there have been discussed the variations in temperature at various locations at the surface and at the height of 5 inches, and the connection existing between these temperatures and the temperature of the soil at the point of exposure. Excepting the minimum thermometers that were exposed in the shelters at Stations 1 at both Mather and Berlin, no reference has previously been made in this paper to the reading of an instrument higher than 5 inches above the surface. In order to supplement the comparison of exposed minimum thermometers at the surface and 5 inches above, readings were made at Mather of instruments at Stations 2 and 9 placed as follows: Surface, 2i inches, 5 inches, 7h inches, 10 inches, 12 inches, 15 inches, and 36 inches above the surface. The character of these stations of course differs radically. Station 2 being located in the bog over sphagnum moss, while Station 9 was in the garden on the upland where the surface was comparatively clean antl the soil a sandy loam. The difference in elevation between the two stations is about 15 feet. The results would have answered the purpose better had both the stations selected for this comparison been located on the bog. Daily, monthly, and seasonal averages appear m Tables 13, 13a, 14, 14a. At Station 2 the minimum temperature averaged lowest for the entire season at the 5-inch height, the average being 40.1°. The temperature gradually increased thence upward and do\vn- ward, being 41.8° at the surface and 43.2° at the 36-inch height, the surface reading therefore averagmg 1.7° higher than at 5 inches and 1.4° lower than at 36 inches. In every month the average temperature was highest at 36 inches, with a secondary maximum at the surface. In May and June the temperature averaged slightly lower at 24 niches than at 5 inches. For the entire season the temperature at 5 inches averaged onl}' 0.2° below that at 24 inches. At Station 9 on the upland the average difference between the thermometers was not so great. The temperature at 24 inches averaged lowest, 44.5°, instead of at 5 inches, as on the bog, but the difference was very slight between these two elevations — 0.1°. The surface ther- mometer averaged highest, 45.5°, but there was only 1° difference on an average between the two extremes, while the average surface reading was 0.6° higher than at 36 inches. The average for the entire season fairly represents the conditions prevailing each month, the highest in each case occurring at the surface and the lowest at 24 inches. While at Station 2 the minimum thermometer was usually the lowest at either 24 inches or 5 inches above the surface, and the temperature averaged higher for each month and the season at 36 inches than at the surface, yet on clear, cool nights, when radiation was the freest, the exposed minimum at 36 inches usually registered lower than at the surface. Moreover, on the coolest nights the difference between the exposed minimum at the surface and the 5-inch height was the greatest, occasional^ exceeding 6°, as in October. (See Table 2.) On warm nights, however, almost without exception, the temperature at 36 inches registered consider- ably higher than at the surface, the maximum difference occurring on June 17, 6.7°, a partly cloudy night. On that date the surface thermometer was 62.1°, the one at 36 inches 68.8°, and at 5 inches 62.9°, this reading being higher than at the surface, and the lowest reading occurring at 2J inches, 62°. At Station 9, of course, the variation was not so great, but it is interesting to note that while the average temperature at this station at the surface was higher than at 36 inches, and this fact was most pronounced on cold, clear nights, nevertheless, on warm nights the reverse was the case, the temperature at 36 inches almost invariably being higher than at the surface ; or, in other words, at both stations, on clear, cool nights the ther- mometers at the 36-inch height usually registered lower than at the surface, and on warm nights the thermometers at 36 inches usually registered higher than at the surface, it being understood, however, that on both cool and warm nights the lowest temperature at both Stations 2 and 9 occurred neither at the surface nor at 36 inches, but at some point between the two, usually at 2^ or 5 inches. On June 17, referred to above, when at Station 2 the surface thermometer registered 62.1°, and at 36 mches 68.8°, the readmgs at similar exposures at Station 9 were 67.1° and 66 67.3°, respectirety, the upper thermometer at Station 2 on the bog actually reading higlier by 1.5° than the one at Station 9 on the upland. On August 10, when the surface instruments at Stations 2 and 9 registered, respectively, 52.6° and 53.1°, the readings at 36 inches were, respectively, 57.8° and 51 .8°, the one on the bog therefore registering 6° higher than the one on the upland. It is important to note that at both Stations 2 and 9 there is an al)rupt change in tempera- ture between the surface and 2^ inches, the readings of the surface instruments being kept up by the conduction of heat from the ground, although unequally. Above 2h inches the change at Station 9 is gradual. The average difference between the readings at 15 inches and 36 inches was only 0.1°, while at Station 2 on the bog the difference was 2.1°. Moreover, at Station 2 the average range for tlie season was 3.1°, from the minimum of 40.1° at 5 inches to the maxi- mum of 43.2° at 36 inches. At Station 9 the average range for similar exposures was onl}' 0.3°, from a minimum of 44.6° at 5 inches to a maximum of 44.9° at 36 inches. However, the extremes at Station 9, as has been stated before, were at the surface and 2i inches, 45.5° and 44.5°, respectivel}', the range being but 1°. Where the minimum thermometers were placed directly one above another, as at Stations 2 and 9, it is obvious that tlie thermometer at 2^ inches is shielded as much by the six thermometers above as the one at the surface by the seven ther- mometers; but, nevertheless, the radiation amidst vegetation should be freer as the elevation increases. The lower down the thermometers are the more the radiation from them is interfered with, laterally and oblicjuely, by the surrounding vegetation. A thermometer or leaf elevated above the ground loses its heat more rapidly than if it rests upon the surface, because in the former case there is likely to be freer radiation in all directiojis; moreover, the heat conducted from the soil beneath affects the thermometer or leaf resting ujion tlie surface and prevents its tem- perature from falling as low as it would if located a few inches above. Of course colder air, being heavier, gradually sinks to lower levels, but this process is very slow, while the processes of radiation and conduction may continue active. The problem is a complicated one, as man}' factors are involved, such as liumidity, wind velocitj'', condition of the sky, barometric pressure, length of night, general temperature conditions, the temperature and composition of the soil, and its moisture and the character of its covering. It is cpiite difficult, however, to explain why the exposed minimum was almost uniformly lower at a few inches above the surface, except on the theory that the surface thermometer receives heat from the soil beneath. In any case, these results are important, as they show approximately the variation in minimum temperature to which vegetation in the bogs is subjected. 67 Table 13. — Minimum Tempkratures in Open at all Elevations at Station 2, Over Sphagnum Moss on the Marsh, Mather, Wis., 1007. May." June. ]iay of month. Sur- face. 2i nches. 5 inches. 7J inches. ID ! nches. 12 inches. 15 inches. 36 nches. Sur- face. 2J nches. 5 nches. 7J nches. 10 nches. 12 inches. 15 inches. 36 inches. I • ' • - • o • = 30.3 30.4 50.0 36.0 36.7 SO.l 43.0 30.2 34.3 52.0 40.2 50.9 35.0 32.3 37.0 47.8 63.1 51.0 48.0 43.8 43.0 59.8 55.0 50.6 54.6 42.4 38.0 39.6 44.8 51.0 S7.S 29.6 52.2 35.4 37.6 28.0 44.0 28.0 32.8 53.0 38.9 50.4 34.4 31.4 35.0 46.0 etc 49.5 46.5 42.3 41.5 58.5 53.7 49.4 52.9 41.0 35.8 36.8 42.5 48.9 n.9 29.4 53.0 35.2 38.0 17.9 44.8 27.9 32.9 53.3 39.1 50.5 34.4 31.0 35.0 46.0 62.9 49.6 46.8 42.3 41.4 59.0 53.9 49.6 53.0 40.9 35.2 36.7 42.6 48.9 28.0 29.8 53.0 35.3 38.8 18. 45.0 28.1 32.8 53.1 39.5 50.5 34.7 31.1 35.0 46.1 6S.9 49.8 47.0 42.2 41.4 59.2 54.0 49.9 53.0 41.1 35.4 36.8 42.8 49.0 o 28.8 29.8 53.0 35.9 39.1 SS.O 45.3 28.5 33.0 53.0 39.8 50.5 35.0 31.1 35.3 46.1 65.0 49.8 47.4 42.5 41.6 59.5 54.1 50.0 53.1 41.8 35.9 37.0 43.0 49.0 28.3 29.0 52.8 35.5 38.9 27.9 45.0 28.0 32.8 52.8 40.0 50.4 35.9 31.0 35.3 46.0 65. S 49.8 47.5 42.5 41.5 59.5 54.1 50.1 53.4 42 1 36.0 37.0 43.0 49.0 28.8 30.1 53.8 36.4 40.0 28.9 46.0 29.0 33.9 53.8 41.1 50.2 36.0 32.0 36.1 47.0 66.8 50.6 48.9 43.1 42.0 60.0 55.1 51.0 54.0 43.1 36.5 37.3 43.7 50.6 32.3 32.8 3 54.0 38.0 5 40.9 6 29.3 46.5 s 30.8 36.0 10 53.8 n 43.8 12 32.5 et.o 45.9 37.5 34.3 32.8 32.8 29.8 SO. 9 23.9 41.0 44.0 36.9 44.8 45.5 29.4 29.2 30.6 36.8 4(.'.8 34.9 59. S 45.0 38.5 34.0 32.0 31.6 28.1 18.0 20.9 43.1 43.8 38.4 44.0 45.3 27.0 27.4 29.4 35.9 45.3 35.2 60. 44.5 36.3 34.1 32.4 32.0 28.2 18.0 21.0 44.0 43.9 40.2 44.0 45.2 27.0 27.3 29.8 36.0 45.0 35.4 60. S 44.9 36.0 34.0 33.0 33.0 28.3 18. S 21.0 44.0 43.9 41.0 44.0 45.0 27.4 27.9 30.0 36.6 45.0 35.9 60. 44.9 36.0 34.0 34.0 34.0 29.1 18.9 21.2 44.0 43.9 41.3 44.0 45.0 27.8 28.0 30.5 36.9 45.1 34.7 S9.S 43.9 35.0 33.0 33.4 33.9 28.6 18.0 20.6 43.0 42.9 40.8 43.0 44.2 27.0 27.4 30.1 36.3 44.8 35.0 eg.s 44.0 35.1 34.9 34.3 35.1 29.3 18 S 20.5 43.0 43.0 41.9 43.0 44.0 27.3 27.8 30.5 36.4 43.8 36.1 61.0 44.8 35.7 34.1 37.4 39.5 33.3 W.$ 22.1 44.0 44.0 42.3 43.7 45.0 29.0 32.4 35.2 40.9 45.6 51.9 13 39.3 14 35.0 15 37.8 16 49.2 17 68.8 18 .53.8 19 51.0 20 45.5 21 44.0 22 60.7 23 57.8 24 53.2 25 55.3 26 44.5 27 38.6 28 39.0 29 46.7 30. 53.1 1 31). 8 36.0 36.2 36.4 36.7 36.0 36.3 38.8 43.3 42.2 42.3 42.5 42.7 42.7 43.5 45.4 a Means for twenty days. Highest and lowest readings are in italics. 68 Table 1.!. — JIiximum Temperatures in Open at all Elevations at Station 2, Over Sphacnum Moss on the Marsh, Mather, Wis., 1907 — Continued. Dav of month. 10. 11. 12. 13. 14. 15. 16. 17. IS. IS). 20. 21. 22. 23. 24. 25. 2B. 27. 28. 29. 30. 31. July. Sur- face. 54.0 SS.l 38.5 47.2 59.0 56.1 47.8 50.9 55.0 46.7 62.9 46.2 48.8 59.9 67.1 50.3 48.0 47.5 54.8 53.7 63.4 60.2 49.1 O60.3 48.9 45.3 44.4 59.0 52.0 49.0 53.0 52.0 2% 5 inches. Inches 51.6 «9.9 38.6 44.4 59.0 52.6 43.7 47.6 51.4 42.8 60.7 42.2 44.6 56.6 67.4 46.6 45.1 45.0 52.0 50.2 60.5 57.0 50.2 59.0 51.1 42.8 41.3 55.0 48.2 46.1 42.9 49.2 52.0 «9.4 38.5 44.7 59.4 52.8 43.3 47.0 51.0 42.3 60.2 42.3 44.6 66.4 67.8 46.3 45.0 44.5 51.8 50.0 60.2 57.3 48.9 58. 7 49.5 42.3 41.0 56.3 48.1 46.0 48.5 49.2 inches 38.7 44.7 59.5 52.9 43.8 47.7 51.0 42.5 59.9 42.1 44.8 56.7 67.9 46.4 45.1 43.9 51.9 50.3 60.1 57.4 49.0 58.8 49.3 42.4 40.6 55.4 48.1 44.9 48.5 49.2 10 inches. 12 inches. 54.3 29.8 38.9 44.8 60.0 53.0 44.0 47.8 61.3 42.8 60.0 42.0 44.7 67.0 68.0 46.6 48.2 44.0 52.0 50.5 60.0 57.9 48.7 58.8 49.2 42.5 40.6 55.7 48.0 44.6 48.4 49 4 54.9 29.7 39.0 44.9 60.0 53.0 44.0 48.0 51.7 43.0 60.0 42.1 44.8 57.5 68. 46.7 45.7 44.2 52.0 51.0 60.2 58.5 48.8 58.9 49.4 42.8 40.8 56.0 48.1 44.4 48.6 49.6 15 inches. 55.9 SO.O 39.8 45.0 60.5 54.8 44.3 49.0 62.2 43.2 60.0 42.4 45.2 58.4 68.1 47.0 46.4 44.6 52.5 52.0 61.0 59.4 49.1 59.7 50.0 43.0 41.0 66.5 49.0 44.5 48.9 50.1 36 inches. 56.4 Sl.i 42.1 46.9 60.5 56.0 46.2 53.0 55.7 46.0 60.1 45,1 48.8 60.5 68 S 48.2 50.0 46.0 54.5 65.0 62.9 61.7 60.0 61.7 50.9 45.0 42.2 58.5 52.0 47.9 51.0 52.1 August. Sur- face. 61.3 44.4 43.0 35.9 68.0 49.4 51.0 54.2 52.0 52.6 70.0 44.9 45.0 48.8 51.9 59.6 46.4 50.2 64.7 38.0 39.5 S5.6 50.0 44.0 35.9 45.0 57.0 51.4 46,0 62.6 53.5 5 inches. 49.4 47.7 40.0 40.5 34.6 58.0 46.8 48.7 51.6 49.0 54.5 70.0 40.3 42.2 46.2 49.7 57.7 43.6 47.7 64.7 34, C 36,2 34.6 47.6 41.6 SS.2 42.8 57.0 50.0 44.5 62.5 52.5 47.4 47.0 39.1 40.0 34.1 57.9 46.0 48.2 51.0 48.9 54.6 70.5 40.1 42.0 46.0 49.6 57.7 43.4 47.7 64.7 34.1 35.7 33.9 47.2 41.0 SS.7 42.5 56.6 49,9 43.7 62.3 62.4 incties. 47.1 47.0 39.4 40.1 SS.2 58,0 46.0 48.1 51.0 49,2 54,5 70.8 40.1 42.6 46.5 60.0 58.2 43.8 47,9 64.9 34.7 36.5 34.6 48,0 41,7 34,0 43,4 67,0 50,7 44.6 62.7 52.7 10 I 12 15 inches, inches, inches. 47.5 46.9 39.5 40.3 SS.t 68,0 46,0 48,2 50,5 49,0 64,5 71,0 40,0 42,3 46,4 49,7 57,8 43,6 47,6 64,6 34,6 36,3 34,2 47,6 41.5 34.0 43.4 56.5 50.6 44,6 62,6 52,7 47,3 46,9 39.7 40.4 SS.S 58,0 46,1 48,5 50,8 49,4 54,9 7/,0 40,3 42.5 46.5 50.0 57.9 43.6 47.7 64.7 34.3 36.4 34,3 47,7 41,8 34,6 43,6 56,4 50,9 44,8 62,7 53.0 47.0 39.9 40.6 S3. 4 58.0 46.2 49.3 50.9 49.6 54.4 70.9 40,3 42.5 46.2 51.6 57.9 46.1 48.0 64,8 35.0 36.6 34,5 48.0 42.5 35.0 43.9 56.7 51.0 44.9 62.6 53.5 inches. 47, 5 47, 8 49.7 42.0 42,9 SB. 4 58.4 49.0 53.0 53.4 52.0 67.8 72.0 45.2 46.3 48.9 54.0 60.0 47.4 62.2 65.2 38 6 40.3 37.3 52.3 46.5 39.0 46.5 56.6 53.6 47.6 63.8 55.8 60.4 Estimated; actual readings valueless on account of heavy rains. Highest and lowest readings are in italics. 69 Table 13. — Minimum Temperatures in Open at all Elevations at Station 2, Over Sphagnum Moss on the Marsh, Mather, Wis.. 1907 — Continued. September. October. Day of month. Sur- face. mcnes. 5 inches. inches. 10 inches. 12 inches. 15 inches. 36 inches. Sur- face 25 inches. 5 inches. inches. 10 inches. 12 inches. 15 Inches. 36 inches. 1 62.3 43.3 41.5 45.7 37.5 35.5 55.2 55.9 33.0 31.4 39.0 38.8 41.7 56.4 58.4 64.6 46.0 57.0 58.6 56.4 31.6 25.0 38.2 41.0 23.3 27.2 29.2 36.0 27.3 S2.S 61.2 42.2 40.6 44.8 36.0 34.3 55.3 55.8 31.0 30.9 37.5 37.3 40.2 57.4 53.7 64-6 44.1 56.3 58.4 56.5 30.3 23.5 37.4 40.8 20.6 25.5 27.7 35.2 25.6 SO.O 60.9 41.9 40.5 44.7 35.5 33.4 54.9 55.6 30.3 30.3 37.4 36.6 40.3 57.3 53.6 64- S 43.6 56.0 58.0 57.2 29.5 22.7 37.0 40.3 19.5 24.7 27.0 34.6 24.6 18.8 61.7 43.0 41.6 45.8 36.9 34.6 55.5 56.3 31.6 31.4 38.5 37.7 40.5 58.0 54.6 64.8 44.5 56.2 58.9 57.5 30.5 23.9 38.5 40.7 21.0 26.0 28.1 35.4 28.8 19.9 61.7 43.5 41.8 46.0 37.1 34.6 55.0 54.9 31.7 31.5 38.7 37.7 40.6 58.0 54.7 64-7 44.6 56.4 59.0 57.3 30.7 24.3 38.9 41.0 21.3 26.0 28.4 35.5 25.9 SO. 2 61.8 43.9 42,4 46.5 37.6 34.7 55.4 56.0 32.2 31.7 39.2 38.0 40.9 58.3 55.0 64-6 44.7 56.4 59.0 57.3 31.0 24.5 39.4 41.0 21.5 26.4 28.6 35.8 26.0 so.s 61.8 44.7 42.7 46.8 38.2 35.2 55.3 56.0 32.6 31.7 39.3 38.1 41.0 58.3 55.0 64.0 44.6 56.5 59.0 57.7 30.8 24.7 39.7 40.5 22.0 26.5 28.7 35.7 26.4 gO.7 65.0 48.2 44.8 49.0 41.1 37.0 55.8 56.6 36.4 34.0 41.9 42.5 43.1 59.5 57.6 65. S 47.4 55.0 60.3 59.0 33.9 27.5 42.9 42.3 23.0 28.5 30.0 37.5 27.3 22.6 29.0 4e.i 38.0 29.6 29.0 35.7 39.0 20.0 33.1 27.7 28.5 24.0 19.6 19.8 40.1 31.7 29.9 19.4 21.1 25.0 18.0 30.0 24.6 21.1 20.7 16.5 29.2 15.4 26.9 35.0 30.0 27.7 46.6 36.6 27.9 27.7 34.3 38.1 17.5 32.8 26.1 27.3 23.3 16.8 17.1 39.8 30.2 28.3 18.3 18.1 22.6 14.6 30.5 22.4 18. S 17.6 13.5 29.3 U.7 26.6 35.3 30.2 26.6 45.1 35.7 27.3 27.0 33.7 37.4 15.9 32.8 25.0 26.0 22.7 15.8 15.6 39.4 29.4 27.4 17.6 17.9 21.9 13.2 30.7 21.9 17.7 17.2 12.5 29.4 10.0 25.7 34.8 29.4 27.8 46.2 36.8 28.5 28.4 34.7 38.5 17.2 34.5 26.4 27.0 24.0 17.0 16.8 40.6 30.6 28.4 19.2 19.0 23.3 14.2 32.5 23.5 19.4 18.9 13.8 30.4 11.5 26.3 35.9 30.4 27.8 46.2 37.0 28.7 28.7 35.1 38.6 17.5 35.0 26.5 27.3 24.4 17.4 17.3 40.9 31.0 28.7 19.6 19.4 23.6 14.6 33.0 23.6 19.8 19.5 14.0 30.2 12. S 26.7 35.9 31.0 28.3 46.4 37.0 29.1 29.5 35.5 38.7 17.6 35.5 26.7 27.5 24.5 17.6 17.4 41.3 31.4 28.7 19.3 19.6 23.8 14.7 33.4 23.7 20.3 19.7 14.5 30.0 12.5 26.9 36.0 31.5 28.0 46.0 37.0 29.6 29.3 35.5 38.6 17.8 35.0 26.5 27.2 24.3 17.7 17.5 41.0 31.4 28.5 19.6 19.8 23.7 14 7 33.5 23.6 20.6 19.4 14.5 29.5 12.5 26.5 35.5 31.5 29.9 ei.o 3 39.0 4 ■ 33.1 5 33.0 6 41.5 42.6 8 19.2 9 39.0 10 29.3 U 30.0 12 26.5 13 19.0 14 18.9 15 . . . . 42.0 16 33.1 17 30.0 18 20.5 19 21.0 20 25.3 21 15.0 00 35.4 23 24.0 24 25 22.5 21.9 26 27 28 14.9 29.8 IS. I 29 26.4 30 35.6 31 32.6 Means 41.9 40.8 40.4 41.3 41.4 41.7 41.8 43.8 27.5 26.0 25.2 26.5 26.8 27.1 27.0 28.9 Table 13a. — Monthly and Seasonal Means of Minimum Temperatures in Open at all Elevations, Station 2, Mather, Wis., 1907. May.' July. August. Septem- ber. Means. Surface 36. 8 2J inches S6.0 5 inches 36. 2 7Unches 36.4 10 inches 36. 7 12 inches 36.0 15 inches 36. 3 36 inches 38.8 43.3 4£.2 42.3 42.5 42.7 42.7 43.5 45.4 62.0 49.4 49.6 50.1 62.1 49.4 47.4 47.1 47.5 47.3 47.5 47.8 60.1 41.9 40.8 40.4 41.3 41.4 41.7 41.8 43.8 a Means for twenty days. Highest and lowest readings are in italics. 27.5 26.0 26.2 26.5 26.8 27.1 27.0 28.9 41.8 40.3 40.1 40.6 40.7 40.8 41.1 43.1 70 Table 1-4. — Minimum Temperatures in Open at all Elevations at Station 9, over Sandy Loaj^on the Upland, Mather, Wis., 1907. Day of month. 9. 10.. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. Means. Mav." Sur- face. 21 inches. 36.7 57.9 46.6 38.3 35.6 41.0 43.7 35.9 SI 9 U.9 44.6 44.3 41.9 44.8 45.8 30.0 31.0 37.2 44.5 47.8 39.! 5 inches. 36.7 SB. 8 45.2 36.3 35.0 39.4 44.7 34.9 23.7 SS.9 44.2 44.0 41.8 43.9 45.1 31.4 30.8 36.1 42.0 46.8 36.7 59.8 45.0 36.0 34.8 39.1 44 9 35.0 23.8 IS.O 44.2 44.0 41.8 44.0 45.1 31.6 31.1 36.3 42.3 46.8 39.3 inches. 10 inches. 37.0 60.5 45.2 36.1 34.8 39.3 45.3 35.7 24.0 S3.1 44.6 44.0 41.8 43.9 45.2 32.0 31.6 36.7 42.2 46.9 39.5 12 inches. 15 36 inches, inches. June. Sur- face. 2i inches. 37.0 37.0 58.7 58.5 45.0 45.1 36.1 36.0 35.0 35.0 39.3 39.1 45.6 46.0 36.0 36.0 24.8 24.9 SS.l $S.l 44.1 44.2 44.0 44.0 41.9 42.0 44.0 44.0 45.0 45.1 32.0 31.9 31.5 31.6 36.8 37.0 42.1 42.0 46.8 46.8 37.0 60.5 46.0 36.0 33.3 39.3 46.0 36.0 25.0 SS.O 44.3 44.0 41.6 43.9 45.0 32.0 31.8 36.9 42.0 46.4 39.4 37.0 60.9 44.9 35.5 34.9 39.4 47.0 36.9 25.9 £3.8 44.0 44.0 42.0 46.7 45.0 32.1 32.0 37.6 42,8 46.4 39.9 33.8 36.9 53.5 44.0 42.1 Si. 7 47.7 34.6 40.9 54.0 45.5 53.0 42.0 38.9 42.5 54.5 67.1 59.0 55. 1 51.6 49.8 60.9 59.1 55.0 56.9 47.0 44.8 46.0 52.1 56.2 48.7 32.2 34.3 53.6 40.3 42.5 Sl.i 46.5 31.8 37.9 53.3 43.5 52.3 40.0 36.0 41.0 52.0 ee.i 55,8 54.8 47.8 46.3 60,7 57.4 53.2 50.7 47.0 42.7 42.0 47.8 53.9 inches. 32.2 34.8 63.8 40.4 42.9 Sl.S 46.5 31.8 37.9 53.4 43.7 52.5 41.1 36.1 41.0 52.0 66.5 55.7 54.9 47.9 46.6 60.6 57.7 53.2 56.5 47.2 42.8 42.1 48.0 64.1 7J inches. 10 I 12 inches. .inches. 32.3 34.9 54.0 40.5 43.0 SI. 7 46.8 31.8 37.9 63.5 43,8 52,6 41,2 36,2 41,0 52,1 66.4 55,7 55,0 47,9 46.9 60,5 67,9 .53,1 56,7 47,3 42,9 42,0 48,1 54,4 15 inches. I 32,4 34,9 53,8 40,6 43.0 St.7 46.7 31.8 37.8 53.4 43.9 52.3 41.2 36.0 40.8 62.0 66.8 56.7 54,9 47,9 46,9 60,6 57,9 53,0 56,6 47,3 42,9 41,9 48,0 54,2 32,2 34.9 54.0 40.5 43.0 SI. 7 46,7 31,8 37,8 53,5 44.0 52.0 41.3 36.1 40.9 52.0 67.9 55.8 64.8 47.7 46.9 60.7 58,0 53,0 56,6 47,1 42,9 41,7 48,0 54,3 46,9 ! 46,9 32,3 34,8 54,0 40,4 43,0 St.g 46.6 Sl.S 37.6 53,7 43,9 52,0 41,3 36,0 40,5 52,0 66.9 55,5 54.9 47.8 46.9 60.8 58.1 53.0 56.8 47.3 43.2 41.8 49.2 54.4 36 inches. 46.9 33.1 35.5 54.3 40.1 43.7 31.4 46.7 31.8 37.6 52.9 44.2 52.0 41.9 36.0 40.6 52.0 67.3 65.8 65.0 47.9 46.4 60.9 68.5 62.9 56.8 47.4 43.3 41.7 49.3 65.0 a Means for twenty days. Highest and iowest readings are in italics. 71 Table 14. — Minimum Temperatures in Open at all Elevations at Station 9, over Sandy Loam on the Upland, Mather, Wis., 1907 — Continued. Day of month. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. IG. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. Meatis 55.0 July. Sur- face. 2J inches. 67.8 SS.3 49.6 52 54.3 59.4 52.7 56.3 61.4 51.9 61.6 48.4 62.0 61.5 68.0 54.1 54.9 51.4 56.6 59.0 65.6 62.5 50.4 62.0 52.8 47.8 44.6 57.1 65.0 50.9 55.1 5 inches. inches. 57.8 33.9 45.0 49.5 60.0 57.3 49.0 56.2 59.9 47.6 60.1 47.0 49.4 60.0 es.o 50.4 53.9 49.0 55.1 58.9 64.0 63.0 49.9 63.1 51.6 47.8 43.4 56.9 55.0 49.9 55.7 53.8 10 inches. 67.9 Si. I 45.2 49.8 60.5 57.6 49.0 56.5 60.0 47.6 60.1 47.3 49.5 60.1 68.0 50.2 54.2 49.0 65.1 59.1 63.7 63.0 50.0 63.4 51.5 47.8 43.2 57.1 56.2 50.0 56.0 12 Inches. 53.9 57.7 Si-S 45.2 49.6 60.3 57.3 48.9 66.4 59.8 47.3 60.1 47.4 49.7 60.2 67.9 60.1 64,0 48.8 55.0 59.0 63.5 63.0 50.1 63.4 51.4 47.7 43.1 67.1 55.0 49.9 55.8 63.8 15 inches. 57.9 34.7 45.3 49.6 60.7 57.4 48.9 66.6 60.0 47.2 60.1 47.5 49.8 60.3 68.0 60.0 54.1 48.9 55.2 59.0 62.8 63.0 50.3 63.7 51.5 47.8 43.1 57.0 55.2 60.0 56.0 53.9 57.9 3i.8 45 5 49 7 60.8 57.5 49.0 56.7 60.0 47.4 60.2 47.8 49.9 60.5 68.0 50.1 54.2 48.8 54.0 69.2 63,6 63.3 60.5 63.8 51.5 47.9 43.1 57.4 56.3 50.1 56.0 54.0 36 inches. 5.S. 3S.0 45.9 49 3 59.4 57.4 48.9 57.1 60.0 47.1 60.0 48.9 60.1 60.9 68.3 50.0 54.6 48.7 64.0 59.5 63.0 63.4 50.6 64.1 51.3 48.0 43.0 57.9 55 9 50.4 56.3 54.1 August. Sur- face. 51. 43.9 46.7 S8.7 59.0 52.9 55.0 55.2 52.1 53.1 71.1 60.0 48.4 51.0 54.2 62.0 49.9 54.8 65.1 42.0 45.2 41.6 52.0 49.5 44.0 51.7 58.0 65.6 51.7 64.0 57.4 2.1 inches, inches. 52.8 43.8 46.5 37. B 58.2 51.0 55.0 53.6 62.0 51.9 71.0 49.0 47.4 50.2 53.8 61.0 48.9 54 64.8 40.6 44.5 40.7 61.9 49.9 43.8 48.7 57.0 54.7 50.6 63.7 56.4 inches 62.1 51.8 52.8 43.9 46.5 37.7 58.2 51.3 55.1 53.8 61.9 62.0 70.9 49.0 47.5 50.4 54.0 61.3 49.0 54.2 65 40.8 44.7 40.8 52.4 50.0 44.2 49.0 57.0 54.9 60.6 63.8 56.7 51.9 52.9 44.0 46.7 37.6 58.1 51.5 5.5.2 54.0 51.9 51.9 71.0 49.1 47.6 50.8 64.4 61,2 49.4 54.4 64.9 41.8 44. S 41.0 52.8 50.0 44.3 49.1 57.2 55.1 50.4 63.8 57.0 62.0 10 inches. 12 inches. 52.6 44.0 46.6 37.6 58.0 51.5 55.1 53.7 51.8 51.7 71.3 49.1 47.5 50.6 54.1 61.2 49.2 54.4 64 7 41.0 44.6 40.9 52.4 50.7 44.3 49.0 56. 7 55.0 50.4 63.7 57.0 51.9 52.7 44.0 46.6 37.4 68.2 51.8 55.4 64.0 61.7 51.7 71.S 49.3 47,5 50,9 54,5 61,3 49.5 54.5 64.8 41.0 44.7 40.9 62,6 50.2 44,5 49.1 57.0 55 2 60.5 63.9 57.2 52.1 15 inches 52.7 44.1 46.7 37.5 58.6 62.0 55 6 53.8 51.7 51.8 71.6 49.2 47.5 50.9 54.4 61.4 49.5 54.9 65.0 40.9 44.6 40.7 52.6 50.8 44.5 49.1 57.0 55.2 50.2 63.8 57.1 30 inches. 52.8 44.1 46, 8 37.2 58.3 51.6 66.0 53.6 61.6 61.8 72.0 49.6 47.5 60.8 64.6 61.2 49.7 54.0 64.1 41.2 44.5 40.8 52.7 51.9 44.7 49.1 56, 5 65.4 50.1 63.7 57.2 51.8 1 52.; Highest and lowest readings are in italics. 72 Table 14. — Minimum Temperatures in Open at all Elevations at Station 9. over Sandy Loam on the Upland, Mather, Wis., 1907 — Continued. * September. October. Day of month. Sur- face. 25 inches. 5 inches. 7* inches. 10 Inches. 12 inches. 15 inches. 36 inches. Sur- face. mches. 5 inches. 75 inches. 10 inches. 12 mches. 15 inches. 36 inches. 1 6B.7 51.0 48.9 52.0 4S.3 40.4 56.0 56.9 38.6 38.7 45.7 44.6 47.3 56.5 56.6 65.0 52.4 58.1 60.3 57.3 36.7 28.0 42.2 42.2 26.4 31.2 32.6 38.0 29.2 iS.O ee.B 51.3 48.8 61.8 43.5 39.4 55.6 56.6 38.2 36.8 45.0 44.7 46.3 56.7 56.8 64.7 50.3 57.7 60.0 58.4 35.1 27.8 42.2 42.3 26.2 29.3 31.5 37.9 28.6 66.7 51.4 48.9 52.0 43.6 39.4 55.6 56.7 38.4 36.8 45.4 44.8 46.3 57.4 57.5 64.8 50.4 57.7 59.9 58.6 35.3 27.8 42.4 42.4 26.3 29.3 31.6 38.0 28.6 2i.7 a 66.7 51.6 49.0 52.2 43.6 39.4 55.7 56.7 38.5 36.9 45.5 44.9 46.4 57.2 57.2 64.8 50.5 57.8 60.0 58.8 35.5 28.1 42.5 42.4 26.4 29.4 31.6 38.2 28.7 25.0 66.7 61.6 48.9 61.8 43.5 39.4 55.5 56.7 38.4 36.7 45.5 45.0 46.3 57.5 57.6 64.7 50.4 57.6 59.7 58.7 34.6 28.3 42.5 42.3 26.4 29.3 31.4 38.1 28.6 15.1 67.0 51.6 49.1 52.1 43.5 39.4 55:7 56.6 38.3 36.7 45.5 45.0 46.5 67.9 57.9 65.0 50.5 57.6 60.3 58.3 35.5 28.0 42.5 42.4 26.4 29.4 31.6 38.2 28.6 15.1 67.0 51.7 49.0 52.0 43.5 39.2 55.6 56.6 38.3 36.7 45.5 45.0 46.4 58.1 58.0 65.0 50.4 57.7 60.2 58.6 35.5 28.2 42.6 42.6 26.5 29.4 31.5 38.2 28.5 15. i 67. B 51.7 49.0 51.9 43.5 39.1 53.5 56.5 38.4 36.5 45.5 45.4 46.4 57.3 56.8 65.0 50.1^ 57.3' 60.1 58.8 35.6 28.6 42.6 41.5 26.5 29.5 31.4 38.0 28.3 25.4 33.8 49.6 44.4 37.7 38.0 42.1 46.1 22.5 36.4 31.6 33.0 27.4 21.5 21.7 42.2 36.4 34.4 23.2 23.8 25.4 18.4 34.4 26.6 23.4 24.6 16.7 32.6 15.2 29.9 36.7 33.9 32.2 Ji9.6 43.5 38.3 38.7 41.6 45.0 20.0 37.2 31.2 33.6 28.0 21.6 18.8 42.5 35.5 33.8 23.0 22.7 25.7 15.6 31.9 26.5 23.0 25.3 14.8 32.8 tS.5 28.8 36.6 34.0 32.3 BO.O 43.6 38. 4 39.0 41.8 45.3 19.8 37.5 31.5 33.7 28.0 21.6 18.9 42.6 35.6 34.2 23.0 23.0 25.8 15.6 35.7 26.6 23.2 25.3 14.8 33.2 IS.B 29.0 36.7 34.3 32.4 50. S 43.6 38.6 39.3 42.3 45.5 19.8 37.7 31.7 33.8 28.4 21.6 19.3 42.6 35.5 34.4 23.2 23.6 26.1 16.2 36.3 26.8 23.3 25.5 14.8 33.4 1S.8 29.0 36.7 34.3 32.4 50.S 43.6 38.6 39.4 42.4 45.5 19.7 37.7 31.8 33.8 28.3 21.6 19.3 42.6 35.5 34.4 23.1 23.6 26.0 16.2 36.4 26.8 23.3 25.5 14.8 33.3 1S.8 29.1 36.6 34.4 32.2 50.6 43.5 38.6 39.4 42.5 45.6 19.7 37.9 31.8 33.8 28.2 21.8 19.3 42.7 35.4 34.4 23.0 23.6 26.1 16.2 36.4 26.8 23.4 25.5 14.8 33.3 IS. 8 29.1 36.4 34.4 32.4 50.7 43.7 38.6 39.3 42.8 45.6 19.6 38.0 31.9 33.9 28.2 21.7 19.3 42.8 35.5 34.4 23.0 23.6 26.0 16.2 36.7 26.9 23.5 25.6 14.7 33.4 U.0 29.0 36.6 34.5 32.1 2 51.1, 3 . 43.4 4 38.9 5 ■-.... 39.6 6 43.6 7 45.7 8 19.5 9 .. 38.5 10 11 12 32.0 34.0 28.4 13 21.7 14 19.3 15 ." 42.8 16 35.0 17 .34.6 18 23.0 19 23.7 20 26.1 21 15.8 22 37.3 23 27.0 24 24.0 25 26 27 28 29 30 31 25.7 14.6 33.1 H.l 28.9 36.1 34.7 • 1 Means 45.6 45.2 45.3 45,4 45.3 45.4 45.4 45.3 31.1 30.5 30.8 31.0 31.0 31.0 31.0 31.1 Table \Aii. — Monthly and Seasonal Means of Minimum Temperatures in Open at all Elevations, Station 9, Mather, Wis., 1907. May." Surface S9.9 2i inches _ 39.2 5 inches 39. 3 7 J inches 39.5 10 inches 39. 4 12 inches I 39.5 15 inches - I 39.4 30 inches ' 39.9 June. i8.7 46.7 46.8 46.9 46.9 46.9 46.9 47.1 £5.0 55.7 53.8 53.9 53.8 53.9 54.0 54.1 .\ugust. 51.6 St. 8 51.9 52.0 51.9 52.1 51.8 52.1 Septem- ber. 45. e 45.2 45.3 45.4 45.3 45.4 45.4 45. 3 a Means for twenty days. Highest and lowest readings are in italics. 31. 1 30.5 30.8 31.0 31.0 31.0 31.0 31.1 Means. 45.5 44-5 44.6 44.8 44.7 44.8 44.8 44.9 73 Comparison of xcind movement over upland and marsh, and effect on temperature, Mather, Wis., 1907. — Not as mucli variation in temperature occurred at Station 9 as at Station 2, because the former was on the upland where there was more lireeze, which mixed the air at different elevations. On clear, cool, quiet nights the cold air settles gradually through gravity toward the surface of tlie earth, hut if the night is windy, tlie air at different elevations is mixed together so that the temperature of the air over a considerable area is nearly uniform. The greatest difference locally is on a clear night when a calm prevails, so that there is no interference with the gradual settling of the cold, heavy air to the surface. Of course the velocity of the wind is least near the sui'face of the earth, due to friction, and the velocity increases witli the elevation. Anemometers placed on the upland and on the bog at Mather show that the variation, even for a slight elevation, is quite decided. (See Tables 15 and 15a.) The anemometer on the upland was located on the cupola of the warehouse, 32 feet 7 inches above the ground and 45 feet 10 inches above the level of the instrument on the marsh. (Fig. 16.) The mean hourly velocity of the wind on the upland for the five months, June to October, inclusive, was 9 miles, while on the marsh it was just half that amount, 4.5 miles. This proportion, moreover, was maintained for the various months. The highest average hourly movement for both exposures was from 12 to 1 p. m., it being 13.7 miles on the upland and 7.9 miles on the bog. The lowest average for any one hour was 6.3 miles on the upland between 2 a. m. and 3 a. m., while on the lowland the lowest was 2.3 miles, this occurring between 9 p. m. and 10 ]i. m., and also from midnight to 4 a. m. For some reason the average on the lowland was slightly higlier between 10 p. m. and midnight, while on the upland there was a gradual decrease every hour from the maximum at 1 ]i. m. to the minimum at 3 a. m. The lowest hourly average movement in the individual months occurred in only one hour in each case. As a rule there was a falling off of the wind after the hour of greatest heat, the movement declining more rapidly in proportion over the bog than on the upland. Frequently at night an absolute calm prevailed on the bog. On several mornings when there was a moderate to fresh wind velocity there was usually a difference of less than 2° between the extremes of the various thermometers at Station 2 on the bog. On August 19, when a fair breeze prevailed, this difference was only 0.6°. There were, on the other hand, many instances of nights of either light wind or of no wind, when a great variation occurred in the readings of the thermometers at different elevations, as on May 30, June 30, July 7 and 13, and October 14, the range at Station 2 being from 4° to 5°. When the wind over tlie ])og was light or calm during the night, the variation m temperature was invariably greater than the average, and when there was a breeze at night the variation was less. Because of the greater movement of the air with increased elevation, the temperature of the air over the upland did not vary as much as on the bog. While there was an average extreme difference of 3.1° between all the readings at Station 2 on the bog for the season, this difference at Station 9 on the upland amounted to only 1°. (Tables 13(7 and 14a.) 74 Table 15.— Average Hourly Wind Velocity on Upland and Marsh, Mather, Wis., 1907. Hour olihi.v- June. July. August, September, October (30 days). Means. Up- land. Marsh. Up- land. Marsh. Up- land, Marsh. Up- land. Marsh. Up- land. Marsh, Up- land. Marsh. 6.4 6.5 e.i 6.2 6.6 6.7 7.8 10.1 10.8 1.9 1.9 US 1.9 2.1 2.9 4.0 5.3 6.1 6.4 6.9 7.1 7.2 7.S 7.0 7.0 6.5 5.5 3.9 2.3 2.1 2.0 2.3 2.1 S.2 5.5 S.S 5.6 5.6 5.4 6.0 7.1 7.3 9.2 10.1 10.4 11.1 11.4 11.8 11.5 11.2 9.4 6.9 5.3 5.5 5.9 5.9 5.8 1.8 1.8 1.9 1.7 1.9 2.5 3.4 4.0 4.7 5.5 6.0 6.4 6.7 6.8 7.0 6.9 6.3 5.3 3.4 1.9 1.6 1.9 2.2 2,2 5,9 S.7 6.1 e.7 5.7 5.6 7.2 8.1 10.0 11.4 12.0 12.5 H.0 13.3 12.9 13.1 11.6 9.5 8.0 6.9 6.6 6.3 6.3 6.3 2.0 2.0 2,0 1.9 2,3 2,6 3.5 4.6 5.8 6.6 6.9 7.5 8.2 7.9 7.5 7,6 6,7 5,3 3.5 2.9 2.3 2.0 2.3 2.3 7.3 7.7 7.1 7.6 8.1 8.1 8.1 9.1 10.8 12.9 14.2 14.6 IB. 8 14.8 14.3 13.2 11.2 8.5 7.3 7.5 7.8 7.5 7.6 7.7 2.9 3.1 2.7 3,1 3,6 3.7 3.9 5.0 6.0 7.1 8.3 8.6 8.7 8.5 8.1 7.5 6.4 4.5 3.0 3.1 3.2 2.8 3.2 3.0 7.0 7,1 7,1 7.5 7.5 7.4 7.4 8.8 11.3 13.0 13.1 13.4 li,.7 13.6 13.9 13.5 11.1 8.3 7.9 7.7 7.7 7.7 6.9 7.2 2,8 2,8 3,0 2,8 3,2 3,1 3,3 4,3 6.1 7.4 7.6 8.0 8.7 8.1 8.1 7.5 6.1 3.7 3.1 3.1 3.1 3.0 2.8 2.6 6.4 6.5 6.S 6.5 6.7 6.7 7.3 8.6 10.0 11.3 12.4 12.8 IS. 7 13.5 13.2 12.8 11.5 9.2 7.7 6.8 6.8 6.8 6.7 e.7 S.S 2.3 2.S 4 a. m . - - . 2.S 2.6 3.0 9 a. m 5 5 10 a. ni - 11 a. m 12 noon Ip.m 2 p. m 3 p. m 4p. m 11.9 12.5 13.1 12.9 IS.i 13.0 12.8 12.3 10.3 8.2 6.8 6.6 6.7 6.9 6.6 7.1 7.3 7.9 7.7 7.5 7.3 6p, m 7p.m 8p. m 9p.m 10 p. m 5.9 3.4 2.7 2.5 s s 11 p. m 2 6 6.7 2 4 Means 9.2 4.3 7.7 3,9 8.8 4.4 9.9 5.0 9,6 4.8 9.0 4 5 Anemometer on warehouse (uplaad), 32 feet 7 inches above ground. Anemometer on marsh, 4 feet 7 inches above ground (Station 4). Anemometer on warehouse, 59 feet 5 inches above surface of marsh at Station 4. Difference between elevations of anemometers, 45 feet 10 inches. Table 15a. — Average Velocity op the Wind, by Months, on Marsh and ITpland, together with AvEitAr.E FOR Five Months, Mather, Wis., 1907. June. July. Upland . Marsh . . . 9.2 4.3 7.7 3.9 August, Septem- ber. 9.9 S.O \ 9.6 4.8 Means. SJ.O 4.. 5 Illgh'^t and lowest readings arc in italics. As has been said before, the air over the bog was often light and even calm on clear, lool nights. When the breeze freshened, the temperature invariably rose near the surface of the bog, although it might at the same time fall on the upland. At Station 5, under such conditions, on July 27, 1906, at Mather, Wis., following a fall in temperature, a rise of 9° occurred between 2.45 a. m. and 3.45 a. m., while during a portion of that jieriod the temperature at Station 1 fell 4°, followed by a rise of the same amount. When the breeze subsided after 4 a. m., the temperature fell again both on the upland and the moorland. With the freshening of the wind, the air over the moorland at different elevations evidenth' became mixed together and a rise in temperature was the result. Over the ujjland, 15 feet higher, although a fall in tem- perature occurred with the first freshening of the wind, the temperature began to rise later, after the breeze had continued for an hour, and the air at different strata for a considerable eleva- tion had become mixed together. (Figure 23 shows the thermograph traces and the wind velocity on both upland and lowland.) 7o s.' ^', Ui'xJM.^ LQWLANC STATION I STATION 5 Fig. 23.— Mather, Wis. Thermograph and anemometer records on July 27, 1906, illustrating marked effect o£ wind on temperature on bog as cinnpared with that on upland. While at night the effect of the wiml on the temperature is often apparent, it is even more pronounced when .some clouds at the same time pass over the moorland. Passing clouds arrest the fall in temperature, and sometimes even cause the temperature to rise. A breeze, of course, usually attends the movement of clouds over a bog. Thermograph traces showmg these irregularities are quite interesting. Such a condition is illustrated by Figure 24, noon to noon, August 30-September 1, 1906, Berlin, Wis., showmg the trace of a tiiermograph located on the bog. AUGUST 3oth. noon mdi SEPTEMBER 31 St. ,. iSt. noon mat noon Fig. 24.— Berlin, Wis. Thermograph record in the marsh. From noon, September 30, to noon, October 1, 1906. The trace shows the effect of passing clouds upon the temperature, both day and night. 76 SEPTEMBER noon mdt. noon Ordinarily a breeze does not cause such a change in temperature on the uphind as^on the moorland. As the cold air settles over the moorland close to the surface on clear, cool nights, a sli'dit freshening of the wind brings warmer air from above, raising the temperature near the surface. This effect, however, can not always be noticed on the upland. The fall in tempera- ture in the shelter on the upland may be steady through the night until the coldest point has been reached, while at the same time the thermograph trace of the instrument placed on the boc may show considerable irregularity. Such a coTidition was noted during the night of September 4-5, 1906, Berlin, Wis., when the wind during the evening up till 11 o'clock was "puffy." (Fig. 25.) Exposed minimum thermometers over feat and sanded logs at the surface, and at elevations of 5 inches and 36 inches, Berlin, Wis. — Because the locations of Stations 2 and 9 at ilather were unlike, not only as regards the character of the soil and its covering, but also as regards elevation, the exposed temperatures between similar heights above the ground are not com- parable. If both stations had been located on the bog, a true comparison might be made between the temperatures of the two stations at several eleva- tions. In the case of Stations 2 and 9 the differ- ence in elevation is probably as important a factor as the difference in the character of the soil. In order to supplement Tables 13 and 14, Table 16 has been prepared from daily minimum readings made at Berlm, Wis., during September, 1906, from instruments exposed at the surface, 5 inches and 36 inches above the surface, at Stations 2 and 3, peat and sanded bogs, respectively, about 100 feet apart and on the same level. Both locations were comparatively clean, the portion of the bog in which they were located having l>een weeded in the spring of that year. On account of the clean surfaces the temperatures were naturally much higher than where the vegetation was dense. Another station, 5, that was maintained at Berlin, and to which refer- ence has been made, was much colder than Station 2, but a thermometer at an elevation of 36 inches was not included in the equipment of that station. The temperature at both Stations 2 and 3 aver- aged lowest at tlie 5-inch height, 47° and 48.6°, respectively. The temperature was highest at the surface, 50.6° and 53.6°, while at the height of 36 inches there were intermediate values, 48.7° and 49°, respectively. The temperature each day was almost invariably lowest at both locations at the 5-inch height, as has been previously shown, and likewise almost invarialily liighest at the surface. While in the sanded bog the surface thermometer registered on an average 5° higher tlian the one at 5 inches, in the peat bog the difference was 3.6°. Moreover, the surface thermometer in the sanded bog registered 4.6° higlier than the one at 36 inches, while in tlie peat bog the difference between the thermometers similarly placed was but 1.9°. At both locations it was warmer at the surface than at the elevation of even 36 inches. This would naturally be expected over the sanded surface. As stated above, the peat soil at Station 2 was comparatively warm, tliat portion of the bog having been thoroughly weeded at the beginning of the season. The peat was, of course, colder than the sanded section, am! it was for this reason that at Station 2 the difference between the readings at 36 inches and the surface was less than at Station 3 in the sanded section. IN VINES IN SHELTER Fig. 25.— Berlin, Wis. Traces of thermograph in shelter on upland and in vines on marsh, noon, September 4 to noon, September f^, 1906. Uncorrected readings. The trace of instrument exposed in the vines is irregular, caused by variation in wind movement. 77 For similar positions at Stations 2 and 3 the average difference was greatest between the surface thermometers, 3°; at the 5-inch height the average difference was 1.6°, while at the height of 36 inches the average difference was only 0.3°. Large differences usually prevailed at the surface, while at 36 inches there was but a single instance of a difference of 1.5° or more, that being 1.6° on September 30, when the temperature was comparatively low. Sometimes the temperature over the peat at the greater elevation was slightly higher than over the sanded surface, and occasionally on days when the difference between the readings of the surface thermometers were marked, as on September 1, 3, 4, and 14, there was but very little difference at the height of 36 inches. These differences in minimum temperature should be considered as entirely due to differences in the character of the soil, as the vegetation ami moisture at the stations were practically the same. The surface of the peat at Station 3 was sanded, especially for the work of this investigation; and while the sand served to raise the night minimums at the surface and a few inches above, it is apparent that its influence was practically lost at an elevation of 3 feet. Ordinarily it should be expected that the differences between the thermometers at two stations at the same heights would decrease with increase of elevation, but this fact can not be demonstrated unless the stations are comparatively close together and all conditions favorable. At Mather, where the stations were far apart, the problem was more complicated. Table 16. — Minimum Temperatures in Open at Surface, 5 Inches above and 3 Feet Above the Surface, AT Stations 2 and 3, Over Peat and Sand, Respectively, together with Dip'ferences Between the Readings, Berlin, Wis., September, 1906. Day of month. inches. 3 leet. Surface. Station 3. inches. 3 feet. Differences. Station 2— surface and 5 inches. station 2— surface and 3 feet. Station 3— surface and 5 inches. Slalion3— surface and 3 feet. Surface. Differences between Stations 2 and 3. 5 inches. 3 feet. 10.. 11.. 12.. 13.. U.. 15.. 16. 17. 18. 19. 20. 21. 22. 23.. 24. 25. 26. 27. 28. 29. 30.. Means. , 44. 58. 44. 43. 38. 46. 50. S3. 57. U2. 65. 62. 54. 35. 45. 56. 59. 61 59. 58, 57. 54. • 48 35. 47. 53. S3. 39. 54. 34: 50.6 41.6 69.3 39.5 38.9 33.1 40.8 47.6 50.0 52.4 57.4 SiO 67.4 53.0 33.0 44.5 54.9 57.3 57.6 58.0 58.0 51.4 47.0 43.8 32.5 38.7 52.8 31.0 31.9 53.6 47.0 45.6 59.0 43.2 41.0 34.8 42.0 61.2 52.4 54.6 69.4 es.g 59.0 53.2 34.7 46.6 56.1 58.5 60.0 58.6 57.8 55.0 48.5 46.5 33.4 40.6 55.1 30.4 35.7 63.5 31.4 48.7 61.5 58.2 52.0 51.0 45.0 52.0 55.0 56.8 59.2 64.5 66.0 63.9 53.9 43.9 4S. 1 56.0 62.3 64.0 60.0 60.0 60.0 56.1 50.4 41.0 45.0 54.8 40.3 43.0 54.3 S9.6 45.5 59.0 43.5 41.5 35.9 42.9 50.0 52.7 54.9 60.0 64.6 59.6 52.8 36.0 44.7 55.4 59.0 60.0 58.1 58.0 54.3 48.6 45.0 34.0 40.0 53.4 SO. 8 35.7 53.5 31.0 45.8 59.2 43.5 41.9 36.9 42.5 51.0 52.3 54.6 60.0 65.6 .59.6 52.9 35.1 46.9 56.0 68.4 60.5 58. 4 58.7 55.3 48.3 45.6 33.5 40.8 65.1 SO. 3 36.1 53.0 33.0 53.6 48.6 49.0 -2.6 +0.9 -5.4 -4.1 -5.3 -5.4 -3.2 -3.6 ', -4.8 I -4.6 -1.1 -4.7 -1.6 -2.6 -1.0 -1.5 -2.3 -4.0 -1.6 -0.9 -6.2 -7.0 -4.7 -3.2 -S.9 -0.5 -2.9 -7.9 -1.2 -5.2 -3.6 + 1.3 +0.6 -1.7 -2.0 -3.6 -4.2 +0.4 -1.2 -2.7 -2.6 +0.1 -3.1 -1.4 -0.9 + 1.1 -0.3 -I.l -1.6 -1.0 -1.1 -2.6 —5.5 -3.0 -2.3 -7.0 +1.8 -3.5 -4.1 -1.3 -2.6 -1.9 -6.0 +0.8 -8.5 -9.5 -9.1 -9.1 -5.0 -4.1 -4.3 -4.5 -1.4 -4.4 -1.1 -8.9 -3.4 -0.6 -3.3 -4.0 -1.9 -2.0 —5.7 -6.6 -5.4 -7.0 -5.0 -1.4 -9. J -7.3 -0.8 -8.6 -5.7 + 1.0 -8.5 -9.1 -9.1 -9.5 -4.0 -4.6 -4.6 -4.5 -0.4 -4.3 -1.0 -8.8 -1.2 0.0 -3.9 -3.6 -1-.6 -1.3 -4.7 -6.8 -4.8 -7.5 -4.2 +0.3 -10.0 -6.9 -1.3 -6.6 -7.3 +0.2 -7.1 -8.0 -6.6 -5.8 -4.2 -3.2 -2.0 -2.5 -0.9 -1.8 +0.7 -8.S -2.6 +0.4 -2.7 -2.4 -0.4 -1.1 -2.4 -1.1 -1.9 -6.3 +2.6 -1.6 -0. 4 -3.2 +0.5 -5.6 -5.0 -3.0 -3.9 +0.S -4.0 -2.6 -2.8 -2.1 -2.4 -2.7 -2.5 -2.6 -0.6 -2.1 +0.2 -2.0 -0.2 -0.6 -1.7 -2.4 -0.1 0.0 -2.9 -1.6 -1.2 -1.5 -1.3 -0.6 +0.2 -3.S +0.1 -2.2 -0.3 -0.2 -0.3 -0.9 -1.1 -0.5 +0.2 +0.1 -0.1 -0.6 -0.4 -0.6 +0.3 -0.4 -0.3 +0.1 +0.1 -0.5 +0.2 -0.9 -0.3 +0.2 -0.1 -0.1 -0.2 0.0 +0.1 -0.4 +0.S -1.6 -1.6 -0.3 Highest and lowest readings arc in italics. 78 Maximum and minimum ietnperatures at different elevations, Station 9, Mather, Wis. — It having been showTi in the discussion of Table 3 that the readings of the exposed Aaximums and minimums located at the surface varied with increasing and decreasing vegetation, it seemed advisable to show the changes in maximum as well as minimum temperature at a single station at different elevations above the surface. Table 17 contains a summar}' of the maximum temperature readings at Station 9 on the upland from May to September, inclusive, 1907, at the surface, 5 inches and 36 inches above the surface. The exposed minimums at these eleva- tions are also given and are the same readings that appear in Table 14. The minimum read- ings, however, in this particular case are not of much importance. There was a steady fall in^ maximum temperature, with increasing elevation for all the months, it being much higher at the surface than at the elevation of 36 inches. The average maximum for the season at the surface was 84.1°; at 5 inches, 79.8°; and at 36 inches, 76.2°. The greatest differences occurred in June and July. On several days the difference exceeded 15°, the greatest difference between the surface and 36 inches being 18.6° on July 20, when the surface reading was 109.3°, and that at 36 inches 90.7°. While these readings do not represent the ah temperature any more than the exposed minimums do, they indicate approxi- mately the degree of heat which affects the vegetation at different elevations. The changes, as a rule, are more abrupt between the surface and 5 inches than between 5 inches and 36 inches. The exposed maximums at the surface registered higher on an average because the surface of any solid upon whicli the sun shines becomes hotter than the air above, the air being heated slightly bj' radiation antl conduction, and largely by convection. All the time while the sun is shining the air resting upon the surface is warmer than the air above, the exposed maximums naturally registering lower with increasing elevation. On cloudy days there was but little difference between the readings of the various thermometers. (For state of weather see Table 22.) The range between the exposed maximum and minimum temperatures was almost always greater at the surface than at the other positions, this tlifference also decreasing with increase of elevation. Table 17. — Monthly and Seasonal Means of Maximum and Minimum Temperatures in the' Open at Different Elevations, Station 9, Mather, Wis,, 1907. May.a June. July. Aug. Sept. Means. Surface: Maximum. 69.2 40.0 89.4 48.7 93.7 55.0 87.4 52.6 80.8 45.6 84 1 48.4 Kange 29.2 40.7 38.7 34.8 35.2 35 7 5 inches: Maximum 65.8 39.4 84.4 46.7 88.5 53.8 84.3 51.9 75.9 45.3 79 8 47.4 26.4 37.7 34.7 32.4 30.6 32.4 36 inches: 63.3 40.1 80. T 47.1 84.1 54.1 80.3 52.1 72.6 45.3 76.2 47.7 Range ^ 23.2 33.6 30.0 28.2 27.3 28.5 a Means Tor nineteen days. Average minimnm tennperatures for the season of 1907 for all locations, together uith soil temperatures, Mather, Wis. — Table IS, giving the average minimum temperature for all expo- sures on tlie marsh at Mather for the season of 1907, together with the average departure from the minimum temperature in the shelter at Station 1, will supplement data already given. There may, at times, seem to be a discrepancy between the averages in some of the tables. On this account the footnotes should in every case be carefully read. Records of some instru- ments are available for the entire season at Mather from May 1, but in most instances the 79 record began on Ma}' 12. There were, however, interruptions at some stations on May 27 and 28, on account of reflowinc; the bog in anticipation of frost. Reflowing also aflVcted the readings at other times (hu'ing the season. The principal feature of interest in Table 18 will be found in the monthly and seasonal departures of the various readings from those in the shelter at Station 1. We can see here at a glance the points of lowest and highest temperature, assuming, of course, that the temperature in the shelter of Station 1 is the standard. Of the minimums in shelters, those at Stations 2 and 5 were the lowest, averaging lower than Station 1 by 3.4° and .3.1°, respectively. The next lowest, as should be expected, was at Station 7, the average diflerence being 2.4°. This station was in the scalped piece, in the midst of an extensive field of sphagnum moss. The average differences for the remaining stations were as follows: Station 6, old .sanded and heavih' vined, 1.9°: Station 4, newly sanded and heavily vined, 1°; Station 9, sandj- loam on tiic upland, 0.fi°: and Station 3, newly sanded and thinly vined, 0.5°. The influence of sanding, draining, and cultivating is well illustrated by these figures. There is usually an interesting relation between these average shelter readings, on one hand, and the maximum soil temperature and the range in soil temperature at the 3-inch depth on the other. Station 7 is the only important exception, and this is because, altliough the soil temperature was relatively high in this small bare section, tiie air temperature was affected by the surrounding field of sphagnum moss. The average shelter reading at Station 9 on the uplantl was 0.1° lower tJian tliat at Station 3, the warmest place on the bog, and the thermometers exposed in the open at the surface at both these stations averaged also within 0.1° of each other, the one at Station 9 being 0.1° higher than the one at Station 3. As has been stated before, the coldest point on the bog was at an elevation of 5 inches at Station 5, where the average was 6.7° below that in the shelter at Station 1, while the thermometer at 5 inches at Station 2 averaged 6.0° below. The greatest average monthly departure was also at the 5-inch heiglit at Station 5, where the radiation was freer than at the surface, the October minimum averaging 8.3° lower than the one in the shelter at Station 1, and an extreme diflerence of 14.6° was recorded on October 24. The greatest differences between the exposed minimums and the minimum in the shelter at Station 1 as a rule occured in October, when radiation was greatest, because of the long, cool nights. The seasonal averages of 40.2° and 40.1° at Stations 2 and 5, respectively, are so close that either might be selected as the coldest point. Sometimes in this bulletin the one at Station 2 has been used, and at other times tlie one at Station 5, according as the one or the other better answered the purpose. Station 2, over sphagnum moss, was located outside the cranberry marsh proper, and was ordinarily not affected by reflowing of the marsh ; wliile Station 5 was in the cranberry bog, but in an uncultivated section, representing the average conditions prevailing in an old bog, without improvement in the way of draining, sanding, and cultivating, just as Station 3 shows approximately the best results prevalent in the AVisconsin bogs. Here, then, are wide difl'erences between the readings of 34 different thermometers in variotis portions of the bog and a neighboring "island." There are, of course, reasons for these variations, the reatlings being afl'ected by the character of the soil and vegetation surrounding each instrument, anil often by the height of the instrument above the soil. As previously stated, while sanding, up to a certain point, is of highest importance in preventing low night temperatures, the character of the soil is of little consequence after frost has entered it. This is evident because the differences between the minimum temperatures are not nearly so great in the month of October as in the warmer months. The temperatures over the sanded surfaces, as compared with the shelter readings at Station 1, are by far the lowest in October. At Station 3, for instance, tlie average departure at the surface for October was 4.5°, while the average for the entire season was but 1.3°, and in the month of July the average was but 0.1°. At Station 4 the minimum thei-mometer similarly located averaged 5.7° lower than the shelter at Station 1 for October, while the average departure for the season was but 3.7°. These facts are in strong contrast with the conditions prevailing at Station 5, .^lil.lir— Bull. T— 1(1 6 80 over peat and moss, where the minimum thermometer at the surface in October averaged 5.3° lower than in the shelter at Station 1, which was only 0.2° greater than the average departure for the entire season, 5.1°. The greatest monthly departure at Station 5 was 5.8° in July, at the time it was least at Station 3. ^Vlthough the temperature at the surface at Station 3 in October was relative!}' low, it was, nevertheless, not as low as at the other stations in the bog. This may or may not show that tlie sanded surface, after frost has entered it, has greater power for warding off lower temperature than the peat and moss soil. It may be that after frost enters the soil tlie capacity for lieat does not vary with the character of the soil, and that rather the difference in minimum temperature over two such surfaces depends then ujxm the character of the vegetation, and that in this instance in October the surface thermometer at Station 3 averaged higher than the surface at Station 5 only because Station 3 was thinly vined as compared with the relatively dense vegetation at Station 5. As explained in previous paragraphs of this bulletin, the temperature at and near the sui'face of the bog is governed large!}' by the character of the soil and its covermg. That tliis is true may be shown by a comparison of the minimum temperature readings with the soil temperature readings, especially at the depth of 3 inches. Table 19 gives the average monthly and the seasonal readings of soil thermometers placed at depths of 3 and 6 inches at the various stations. This table is the summar}' of extensive data which, for lack of space, it was found impracticable to print. Bj' comparing Tables IS and 19 it will be found that the exposed minimum temperatures at the surface at the various .stations, as a rule, averaged highest where the 6 J), m. or maximum soil temperatures at the 3-inch depth were the greatest, and also where the range in soil temperature at the 3-inch depth was the greatest. Station 7 in the scalped piece is an exception to this rule, for reasons already given. In other words, the highest mini- mums occurred at places where the soil was heated considerably in the daytime, while at places where the soil temperature varied little on account of dense vegetation and lack of sanding anti tlraining, the exposed minimum thermometers registered the lowest. The range in soil temperature at the 3-inch depth was naturallj- much greater than at the depth of 6 inches, and where the covering was exceptionally dense there was practically no range in soil temperature at the latter depth, as at Stations 2 and 5. It is evident, by referring to Figures 20 and 22, and to the soil temperature figures at the 3-inch and 6-inch depths in Table 19, that the clean soil during the daj^time is not onl_y heated considerablj^ near the surface in the thinly A'uied and bare sections, but also that the heat descends to a greater depth, and it is because of this heat stored in the groimd that the air above does not become as cold at night. The greater conduction of heat b}^ the sanded soil at Station 3 and the sandy loam at Station 9 than by the plam peat at Station 7 is partially shown bj' the soil temperature readings at these stations, although a considerable portion of the heat received at Station 7 was expended in the evapo- ration of the superfluous moisture. The average dailj' ranges at Station 7 at the depths of 3 and 6 inches were, respectively, 5.1° and 1.4°, while at Stations 3 and 9 the ranges were, respec- tively, 8.2° and 4°, and 10.1°'and 7.7°. 81 Table 18. — Monthly and Seasonal Means op all Minimum Thermometers, with Departures from Mean OF Station 1, Mather, Wis., 1907. station 1: Shelter Station 2 (moss over peat): Shelter Surface 2^ inches 5 inches 7i inches 10 inches '... 12 inches 15 inches 36 inches Station 3 (newly sanded, thinly vined): Sheller Surface 5 inches 36 inches Station 4 (newly sanded, heavily vined); Shelter Surface 5 inches Station 5 (peat and moss, heavily vined): Shelter Surface 5 inches Station 6 (old sanded, heavily vined): Shelter Surface 5 inches Station 7 (scalped peat): Shelter Surface 5 inches Station 9 (sandy loam): Shelter Surface 2J inches 5 inches THnches 10 inches 12 inches 1.5 inches 36 inches May.a Month- ly mean. Month- ly de- parture. June. Month- I.v mean. Month- ly de- parture. 38.9 37.6 S7.0 SI. 2 37.4 37.7 S7.0 37.3 39.2 40.4 39.3 39.2 41.2 38.4 38.8 39.7 37.1 37.2 40.4 38.7 38.0 39.9 37.6 37.6 41.2 40.9 40.1 40.1 40.4 40.3 40.3 40.3 40. S -2.8 -4.1 -■«•? -4.5 -4.3 -4.0 -i-7 -4.4 -0.5 -1.3 -2.4 -2.5 -0.5 -3.3 -2.9 -2.0 -4.6 -4.5 -1.3 -3.0 -3.7 -1.8 -4-1 -4.1 -0.5 -0.8 -1.6 -1.6 -1.3 -1.4 -1.4 -1.4 -0.9 45.4 43.3 42.2 42.3 42.5 42.7 42.7 43.5 45.4 48.9 48.8 46.3 45.9 48.4 45.2 45.7 45.7 43.5 il.S 47.0 44.0 43.2 46.3 44.0 43.0 48.4 I 48.7 I 46.7 46. S 46.9 46.9 46.9 46.9 47.1 July- August. Month-i Month- ly I ly de- mean, parture. 55-6 3.6 51.8 5.7 52.0 6.8 49.2 6.7 49.2 6.5 49.2 6.3 49.4 6.3 49-6 5.5 50.1 3.6 52.1 -0.1 -0.2 -2.7 -3.1 -0-6 -4.0 -3.3 -3.3 -5.5 -2.0 -5.0 -5.8 -2.7 -5.0 -6.0 -0.6 -0.3 -2.3 -2.2 -2.1 -2.1 -2.1 -2.1 -1.9 5S.S 55.5 53-0 51.7 54.9 52.3 52.4 S3.1 49. S iB.S 53.8 50.3 49.6 53.0 51.2 50.2 55.4 55.0 53.7 53.8 53.9 53.8 53.9 54.0 54.1 -3.8 -3.6 -6.4 -6.4 -6.4 -0.2 -6.0 -5.5 -3.5 0.0 -0.1 -2.6 -3.9 -0.7 -3.3 -3-2 -2.5 -5.8 -S.8 -1.8 -5.3 -6.0 -2.6 -4.4 -5.4 -0.2 -0.6 -1.9 -1.8 -1.7 -1.8 -1.7 -1.6 -1.5 Month-' Month- ly I ly de- September. mean, parture. mean, parture. mean 50.1 -3.8 49.4 -4.5 47.4 -6.5 ir.i -e.s 47.5 -6.4 47.3 -6.6 47.5 -6.4 47.8 -6.1 50.4 -3.5 53. « 53.7 51.2 48.3 53.1 50.6 50-6 50.3 48.8 ff.l 52.1 49.3 48.3 51.6 I 49.2 53.4 52.6 51-8 51.9 52.0 51.9 52.1 51.8 52.1 -O.f -0.2 -2.7 -5.G -0.8 -3.3 -3.3 -3.6 -5.1 -6.8 -1.8 -4.6 -5.6 -2.3 -4.7 -4.9 -0.5 -1.3 -2.1 -2.0 -19 -2.0 -1.8 -2.1 -1.8 Month- Month- ly Iv de- 44.3 41.9 40.8 1,0. J, 41.3 41.4 41.7 41.8 43.8 -4«.7 45.9 44.6 42.7 46.3 41.2 44.1 44.1 43.0 40.7 45.3 43.1 41.7 46.5 45.6 45.2 45.3 45.4 45.3 45.4 45.4 45.3 -2.8 -5.2 -6.3 -6.7 -5.8 -5.7 -5.4 -5-3 -3-3 -0-4 -1.2 -2.5 -4.4 -0.8 -2.9 -3.0 -3.0 -4.1 -6.4 -1.8 -4.0 -5.4 Month- ly 45.0 -2.1 42.3 -4.8 42.6 -4.5 -0.8 -1.5 -1.9 -1.8 -1.7 -1.8 -1.7 -1.7 -1.8 Month- ly de- parture 30.0 27.6 26.0 25.2 26.5 26.8 27.1 27.0 28.9 31.6 28.8 28.5 29.2 31.2 27.6 27.4 29.2 28.0 u.o 30.8 28.3 26.1 30.8 27.9 27.7 Si.S 31.1 30.5 30.8 31.0 31.0 31.0 31.0 31.1 Sea- sonal mean. -3.3 -5-8 -7.3 -8.1 -6.8 -6.5 -6.2 -6.3 -4-4 -1-7 -4.5 -4.8 -4-1 -2.1 -5.7 -5.9 -4-1 -5.3 -8.S -2.5 -5-0 -7-2 -2-5 -5.4 -5.6 4.3.4 41.9 40.4 40.2 40.7 40.9 40.9 41.2 43.3 lfi.3 45.5 43.8 42.8 45.8 43.1 43.2 43.7 41.7 Ifi.l 44.9 42.3 41.2 44.4 42.0 41.7 Sea- sonal depar- ture. 1.0 46.2 2.2 45.6 2.8 44.7 2.5 44.8 2.3 44.9 2.3 44.9 2.3 44.9 2.3 44.9 2.2 45.1 -3-4 -4.9 -6.4 -6.6 -6.1 -5.9 -5.9 -5.6 -3.5 -0.6 -1.3 -3.0 -4.0 -1-0 -3-7 -3.6 -3.1 -5.1 -e.7 -1-9 -4.5 -5.6 -2.4 -4.8 -M -0.6 -1.2 -2.1 -2.0 -1.9 -1.9 -1.9 -1.9 -1.7 Stations 1 and 9 on upland; others ou bog '! Mean for eighteen days. One thermometer in shelter at each station; others exposed in open. Highest and low est readings are in italics. 82 Table 19. — Monthly and Seasonal Means of Soil Thermometer Readings at 3 Inch and 6 Inch Depth. M.\THER, Wis.. 1907. [The li p. m. rouciings opciirrod the previous day, and *' Ditlereuce" shows the change during the night.] May." June. 1 July. August. Septem- ber. October. Means. Station 2: 3-ineh depth— " ° ° » " ° " 6 p. m 39.0 56.0 65.0 62.3 57 3 40 SI. 7 37.5 53.0 02.6 61.2 56.5 45.4 Difference... - 2.1 - 3.0 - 2.4 - 1.1 - 0.8 - 0.6 - 1.7 6-inch depth— i 6p. m 34.8 52. S 63.2 62.2 58.3 48.2 53.3 7 a. ra. 34.7 53.2 63.4 62.3 58.2 48.1 S3. 3 Difference.. - 0.1 ■f 0.4 + 0.2 -1- 0.1 - 0.1 - 0.1 0.0 Station 3: ^ 3-inch depth— 55.8 65.8 71.8 68.0 63.2 " 7 a. m. 48.0 56.9 63.1 61.4 55.3 41.9 54.4 Difference - 7.8 - 8.9 - 8.7 - 7.2 - 7.9 - 7.7 - 8.2 ()-inch depth— 6p.ni... .... 53 6 62 1 68 3 65 7 61 47 9 59 8 50.0 57.5 63.7 62.1 57.1 44.4 55.8 - 3.6 - 4.B - 4.6 - 3.6 - 3.9 - 3.5 - 4.0 Station 4: 3-inch depth— 50.3 60.3 64.6 7 a. m 47.5 56.5 63.2 61.5 56.5 44.0 54.9 Difference - 2.8 - 3.8 - 3.7 - 3.1 - 2.8 - 2.6 - 3.1 6-inch depth- 50.2 55.0 47.6 56.5 63.5 62.3 57.8 46.0 - 0.1 - 0.0 - 0.7 - 0.6 -0.7 - 0.5 Station 5: I> 3-inch depth— 6 p. m 48 5 57 9 66 "* 64 57 *' 45 9 50 7 a. m 47.5 55.6 63.6 62.1 56.5 45.5 S5 1 Difference -1.0 - - 2.3 - 2.6 - 1.9 - 0.7 - 0.4 - 1.5 6-inch depth — 6p. m 47.1 54.8 63.7 02.3 56.7 46.7 55.2 7 a. m ■17.2 55.0 63.5 02.2 66.9 46.6 55.2 -f 0.1 ,+ 0.2 - 0.2 - 0.1 + 0.2 - 0.1 Station 6; 3-inch depth— 6 p. m 49 4 59 1 65 9 63 6 58 5 57 2 7 a. ni 47.3 56.3 63.4 01.4 56.3 44.0 Difference - 2.1 - 2.8 - 2.5 - 2.2 - 2.2 - 2.0 6-inch depth— 6 p. m 4fi. 8 03.2 62.3 58.1 7 a. m 46.9 56.1 02.9 61.9 57.7 46.8 55 4 Difference -1- 0.1 - 0.3 -0.3 - 0.4 - 0.4 - 0.3 2 a Means for seventeen days. !> On .Vugust 10 and 12 a light covering ot mo.ss was placed around and between soil thermometers at Station 3. On .\ugust 25, at Station 3 position of bo.x on which soil tlierniograpli rested was clianged so as to allow more sunshine around soil thermometers during morning hours. On August 24, at Station 5 positions of soil thermographs were changed and placed under proper conditions of live moss and vines. Station 2. Sphagnum moss. Station 3. Newly sanded, thinly vlned. Station 4. Newly sanded, heavily vined. Highest and lowest readings are in italics Station 5. Peat with moss, heavily vlned. .station 0. Old sanded, heavily vined. 83 T-A.BLE 19. — Monthly and Season.\i, Means op Soil Thermometer Readings at .i Inch and 6 Inch Depth, Mather, Wi^i.. 1!)07 — Continued. May. ' June. July. August. Septem- ber. 61.4 55.6 October. Means. Station 7: 3-inch depth— 6 p. m 49.5 45.9 o 61.9 56.2 68.8 63.4 66.9 62.0- 48.6 43.6 59.5 54.4 DilTerence - 3.6 - 5.7 - 5.4 - 4.9 - 5.8 - 5.0 - 5.1 Ij-inch depth- 45.1 44.9 ,58.7 56.9 66.1 64.4 65. 1 63.5 59.3 57.7 / - 47.1 45.8 56.9 55.5 Difference... - 0.2 - 1.8 - 1.7 - 1.6 - 1.6 - 1.3 - 1.4 Station 9: 3-inch depth— 56.8 47.2 69.1 58.0 75.2 64.0 70.9 61.4 63.5 54.8 53.0 42.7 «4.8 - 9.6 55.3 4S.6 -11.1 67.9 58.9 -11.2 74.4 65.3 - 9.5 70.8 62.8 - 8.7 63.0 56.6 -10.3 52.0 44.7 -10.1 6S.9 56. i ti-inch depth- Difference .. — I'l. 7 - 9.0 - 9.1 - 8.0 - 6.4 - 7.3 - 7.7 Station 7. Scalped piece, bare peat, in a field of sphagnum moss. Highest and lowest readings are in italics. Station 9. Sandy loam on upland . That the rau'^e in soil temperature was mucli greater at Station 3 tlian at Station 5, and at the 3-inch ilepth tiian at the depth of 6 inches at both stations, is shown graphically by Figure 20, previously referred to, which gives the hourly traces from soil thermographs for the season of 1907 at each station. Figures 21 and 22, which have already been discussed, bear ilirectly upon this question of air and soil temperatures. While the maximum at 3 inches occurred at both stations from 4 to 6 p. m., and the minimum from 6 to 7 a. m., the maximum and the minimum at 6 inches at Station 3 occurred a few hours later, and at the 6-inch depth at Station 5 the maximum occurred from S to 9 a. m. and the minimum about 5 p. m. The curve at Station 3 at the 3-inch depth is, of course, abrupt as compared with the curves at the other exposures. Figure 19, also previously referred to, shows the curve of the soil thermograph recortls at Stations 3, 4, and 5 for the week of September 23-30, inclusive, 1906. The great range in temperature in the thinly vined and newly sanded section as compared with that in the peat bog with moss is apparent, while the one exposed in the heavil}^ vined and newly sanded sec- tion has an intermediate A'alue. The changes in soil temperature at Station 3 are again shown to be abrupt as compared with those at the other stations, the minimum being below as much as the maximum was above. Of course, the location at Station 3 was responsive to changes in air temperature, while the changes where the vegetation was dense lagged behind and were relatively slight. A soil thermograph was located in the reservoir so as to secure a continuous record of water temperature 12 inches below the surface, while an air thermograph was placed in a shelter over the bog 5 inches above the surface. In Figure 26 are shown the curves of these two instruments, and also the curve of the soil thermograph over a peat and moss bog, for the week of September 23-30, inclusive, 1906. Here we have tin interesting illustration of the daily variation in temperature in three elements — air, earth, and water — within a comparatively small area. 84 In Figure 27 the curves of air temperature, water temperature, and soil tempe|jp.ture for the week of September 16-23, inclusive, 1906, are ilKistrated. It is interesting to note tlie lagging of the changes in temperature of the soil and water behmd those of the air. Relation hetween dew-point and minimum temperature. — A diy atmosphere permits freer radiation of heat from the grounfl than moist air. Moist air absorbs part of the lieat radiated from the ground, and consec[uently does not permit as low temperatures as when the air is diy. The marsh region of Wisconsin, however, is almost always humid at night, but remarkably low temperatures, nevertheless, occur in spite of these humid conditions. It may be that under such conditions the air some little distance above the bog is relativelj' dry and jiermits rapid radiation through it. It has long been supposed that a relation exists between the dew-point and the ensuing minimum air temperature, and that, if the dew-point at the time of observation in the evening was higher than 32°, fro.st should not be expected that night. It was believed that, the dew- point having been reached, latent heat would be given off in the operation of condensation and prevent any further fall in temperature. This is a plausible theory, and many cranberry TT^iT ■ ■}/.■ . «•.- „\i/,. J , ,. V.-, i ,...\j, , . ....Mr, . ;. ..17,, y. „y, , ; , .y/vy;.^^/, . ;...a, . /. ,.,R.,, i'n-^>_i_liftH44. ::H.— Temperature curves of air, soil and water tor Mather, Wis., September 23 to 30, 1906. Air temperature in shelter over bog temperature of water in reservoir 12" below surface, — x— x— x— x— x— x— x— x; soil temperature 3" deep in peat bog with - ////fS :;f-,:2 :,'Iuf.T=i.7-i ■ / --m^ ^"=^£^13^ ^'—^ m^M^ -1—-^ ■+I Fig. 27.— Temperature curves of air, soil and water for Stations 3 and 5, Mather, Wis., September 16 to 23, 1906. Air temperature, station 5, in shelter, : soil temperature, station .s, 3 in. deep, — x— x— x— x — x— x— x; soil temperature, station 3, 3 in. deep . temperature of water in reservoir, 12 in. below surface . growers have confidence in it, but the observations made on the bogs show that the dew-point itself is no indication whatever of the ensuing minimum temperature. The dew-point observations were made at Mather with the Assman aspiration psychrom- eter exposed on the upland about 4 feet above the ground at Station 1 and on the bog about 1 foot above the' ground at Station 4. During the season of 1907 the dew-point on the upland was generally lower at 9 p. m. than at 6 p. m., the average difference for the season being 1.9°. (Tables 20 and 20a.) However, the ensuing minimum temperature in the shelter at Station 1 was almost invariably lower than the 9 p. m. dew-point reading, the average depression for the season being 3.3°. The latest dew-point observation made daily at Station 4 was at 6 p. m. On account of the larger amount of moisture prevalent on "the bog, the dew-point was naturally higher there than on the upland, there being an average difference between the 6 p. m. readings of 1.5°. The average of the dew-point readings for the season of 1907 at Station 4 was 7.6° higher than the mean of the ensuing minimum air temperatures in the shelter at the same station on the bog, as compared with an average difference of 8.2°, noted in the season of 1906. Moreover, at Station 4 the minimum in the open averaged 2.6° lower than in the shelter. (Table 1.) The 85 average temperature at one of the coldest points on the bog in the open — the .5-inch height at Station 2— rwas 13.7° below the average of the dew-point readings at Station 4 during the season of 1907. On some nights the temperature in the shelter at Station 4 was 18° to 20° lower than the dew-point. On one night, September 29-.30, it was 28° lower, and this in spite of the fact that the relative humidity on the bog earh' the previous evening was as high as 94 per cent. The temperature in the open at Station 2 was often as much as 25° lower, and on September 30 it was 30° lower. In a few cases the ensuing minimum temperatures were liigher, as for instance on June 3 and 10, July 1 1 , August 3 1 , and October 9 and 1 .5, when the weather was cloudy. During cloudy weather the dew-point and the muaimum temperature at Station 4 were often the same. According to these observations the formation of dew and fog has no appreciable effect in preventing the fall of the minimum temperature to a low point, such a fog often lying in a thin stratum over the marsh; in fact, the greatest departures often occurred on nights of dew and fog when the sky above was clear. Of course, latent heat is given off in the process of condensation, but the amount is ob^^ously small as compared witli the vast area of cold air overlying the moorland. Table 22 should be used in connection with Table 20 for pur- poses of comparison regarding fog and dew. It is apparent then from the above that in the moorlands the dew-point in the evening is no indication of the ensuing minimum temperature. Naturally if the air were drier, the tem- perature would fall to a lower pomt, but the air is usually humid in the bogs, as stated above. The vapor in the air is so great that ordinarih" on clear cool nights dew forms even at sunset. In spite of the fact that the air may be saturated with moisture, the temperature frequently continues to fall steadily through the night, demonstrating that the latent heat given off in condensation has but little effect in retarding the fall in temperature. The thermograph traces of the instruments exposed in the open often show a stead^^ decline m temperature on nights of dew and fog when the sky is clear. 86 Table 20. — Comparison- of Dew-point Readings on the Upland at 6 and 9 p. m., with Ensuing Minimum Temperatures in the Shelter; also of Dew-point Readings on the Marsh at 6 p. m., wit^Ensuing Minimum Temperatures, and Differences at Station 4; also Ensuing Minimum Temperatures in Open, AND Differences at Station 2, Mather, Wis., 1907. [Dew-point readings occurred the previous day.] Junt'. July. -Vugust. Upland, Sta- tion 1— shelter. Marsh. Upland, Sta- tion 1 — shelter. Marsh. Upland, Sta- tion 1— shelter. Marsh. Day of month. Dew- point. Station 4— shelter. Station 2— 5 inches, exposed. Dew- point . 1 S Station 4— shelter. Station 2— 5 inches, exposed. Dew- point. 6 i a S Station 4 — .shelter. Station 2— 5 inches, eicposed. «3 g d OS 1 a S •d g p. s a i 5 C S g a d £ d d ■6 d g 5 .§ c ia O C o 1 H o E .1 c i 1 B d e d a, d i s 1 5 1 1 „ u 1 o . o . . . . . c o . <, o o o 1 Si SS 36 S4 SS + 1 28 - 6 64 62 59 62 58 - 4 52 -10 57 68 55 62 53 -9 47 -15 2 40 41 39 43 36 - 7 29 -14 53 50 SS 53 S7 -16 29 -24 52 47 46 49 45 -4 39 -10 3 46 49 55 48 55 -1- 7 53 + 5 50 60 48 SI 47 - 4 38 -13 52 53 48 54 47 - 7 40 -14 4 62 50 41 51 42 -9 35 -16 67 61 51 65 51 -14 45 -20 49 48 39 54 43 -11 34 -20 5 44 45 44 42 44 + 2 38 - 4 66 65 60 66 61 -5 59 - 7 54 61 59 56 59 -1- 3 58 -F S 6 36 40 Si 39 36 - 3 SS -11 70 ' 68 S8 70 58 -12 53 -17 57 56 54 59 62 - 7 46 -13 7 45 45 48 48 48 45 - 3 56 1 54 51 60 61 - 9 43 -17 70 63 57 71 56 -15 48 -23 8 38 39 36 42 SS - 7 iS -14 69 67 59 67 55 -12 47 -20 58 , 57 55 62 56-6 51 -11 9 39 39 41 42 40 - 2 32 -10 62 63 61 63 60 - 3 51 -12 69 59 54 60 54-6 49 -11 10 47 43 54 46 55 -1- 9 53 -1- 7 57 56 50 59 50 - 9 42 -17 70 69 59 69 60-9 56 -14 11 60 57 47 61 46 -15 39 -22 59 60 60 59 61 + S 60 + 1 71 70 74 72 70-2 70 - 2 12 54 50 53 54 53 - 1 50 - 4 60 60 51 60 48 -12 42 -18 56 i2 53 57 49-8 40 -17 13 51 50 44 54 42 -12 34 -20 60 69 54 61 52 - 9 44 -17 56 57 60 58 49-9 i2 -16 14 46 48 39 50 40 -10 31 -19 62 69 62 62 62 56 - 6 58 59 53 59 53 - 6 46 -13 15 51 53 43 60 41 -19 35 -SS 69 67 6S 68 68 68 64 60 56 64 56-8 50 -14 16 56 54 54 56 53 - 3 46 -10 64 60 51 66 52 -14 46 -20 66 64 61 66 62 - 4 58 - 8 17 70 68 70 70 69 - 1 63 - 7 70 67 57 70 52 -18 45 -S5 60 52 52 54 50 - 4 43 -11 18 64 65 59 67 57 -10 50 -17 56 59 50 63 50 -13 44 -19 60 60 57 59 54 - 5 48 -11 19 64 56 57 64 56 - 8 47 -17 62 62 66 64 57 - 7 52 -12 67 66 65 68 65 - 3 65 - 3 20 56 55 51 61 50 -11 42 -19 67 65 61 66 59 - 7 50 -16 54 51 4S 52 42 1-10 34 -18 21 58 55 49 60 49 -11 41 -19 62 67 64 69 65 - 4 60 - 9 47 43 47 49 48 -1 36 -13 22 64 62 61 64 62 - 2 59 - 5 68 66 64 68 63 - 5 57 -11 63 50 43 53 41 -12 34 -19 23 67 65 60 67 60 — 7 54 -13 61 59 53 63 52 -11 49 -14 56 53 54 55 54 - 1 47 - 8 24 63 64 54 65 55 -10 50 -15 67 65 64 67 64 - 3 59 - 8 67 61 54 67 51 -16 41 -se 25 66 61 58 69 57 -12 S3 -16 60 64 53 64 54 -10 50 -14 62 48 48 62 43-9 SS -19 26 48 52 48 51 48 - 3 41 -10 64 62 49 65 48 -17 42 -23 62 49 51 58 60-8. 42 -16 27 49 53 45 54 43 -11 35 -19 68 60 45 60 46 -14 41 -19 57 55 56 56 66 56 28 56 54 43 61 44 -17 37 -24 59 61 59 60 59 - 1 55 - 5 63 62 58 64 56 - 8 60 -14 29 58 56 51 59 50 - 9 43 -16 59 58 67 60 56 - 4 48 -12 64 56 51 63 51 -12 44 -19 30 64 62 58 65 56 - 9 49 -16 53 53 53 56 50 - 6 45 -11 64 64 64 64 64 62 - 2 31. 66 62 58 66 55 -11 48 -18 67 61 58 54 58 + 4 52 - 2 52.9 Means. 52.1 49.1 54.9 48.6 -6.3 42.3 -12.6 62.3 60.7 55.6 63.0 54.9 -8.1 49.0 -14.0 59.1 66.3 54.0 59.4 53.1 -6.3 47.1 -12.3 Uighest and lowest readings are in italics. Table 20. — Comparison op Dew-point Readings on the Upland at U and 9 r. M., with Ensuing Minimum Temperatures in the Shelter; also of Dew-point Readings on the Marsh at 6 p. m., with Ensuing Minimum Temperatures and Differences at Station 4; also Ensuing Minimum Temperatures in Open, and Differences at Station 2, Mather. Wis., 1907 — Continued. September. October. Upland, Station 1— shelter. Marsh. Upland, Station 1— shelter. Marsh. l->ay of month. Dew-point. Mini- mum. .Station 4— shelter. Station 2— 5 inches, exposed. Dew-point. Mmi- mum. Station 4— shelter. Station 2- 5 inches, exposed. 6t>. in. 9 p.m. d.p. 6 p.m. Mini- Difler- mum. ence. Mini- mum. Differ- ence. 6 p.m. 9 p.m. d.p. 6 p.m. Mini- mum. Differ- ence. Mini- mum. Differ- ence. 1 n 01 48 54 52 53 57 58 49 49 51 54 59 61 64 63 67 69 54 5/ 49 48 34 36 44 71 55 50 52 49 52 55 58 50 43 47 52 57 58 59 66 58 62 66 66 43 43 46 46 SI 33 42 70 53 50 52 44 41 54 56 40 38 45 48 50 62 63 67 .53 58 61 60 38 31 45 43 18 34 34 37 29 SS a 76 61 54 56 57 56 .t6 58 52 48 53 59 61 66 64 73 67 S3 70 71 54 S6 s a 68 - 8 52 ' - 9 50 - 4 53 - 3 44 -13 41 -15 56 56 -2 40 ' -12 42-6 45 - 8 43 -16 47 -14 s; -15 a 40 50 H Si 41 50 48 35 51 46 51 44 44 51 o 33 52 46 41 41 44 50 23 40 35 35 29 25 22 44 36 39 24 27 28 19 40 30 29 28 19 34 17 32 37 37 39 52 54 56 36 49 55 44 32 43 42 30 32 26 36 39 50 36 26 36 28 41 45 46 35 29 35 20 35 40 41 33 « 43 37 38 42 44 22 40 31 35 29 22 20 44 36 33 24 22 27 18 36 26 25 25 18 34 16 28 37 35 - 6 -11 -19 -^ 2 - 7 -11 -iS + 8 -12 - 7 - 1 -10 - 6 -1- S - 3 -17 -12 - 4 - 9 -10 - 5 -19 -21 -10 -11 - 1 - 4 - 3 - 6 27 iS 36 27 27 34 37 16 -12 9 42 -19 40 -14 45 -11 _ 7 3 -18 4 -?» 5 36 33 -21 -23 - 9 6 -15 7 55 — / 56 - 2 30 -22 30 -18 37 -16 37 -22 40 -21 -IS 8 14 :;_' 43 38 29 30 30 36 31 21 -28 9. 33 + 1 10 25 26 23 16 16 39 29 27 18 18 22 13 31 22 18 17 12 29 -18 11 -16 12 - 7 13 . .. -16 14 15 16 17 18 . 60 60 66 52 58 61 59 38 35 - 8 - 4 - 7 -15 - 5 - 9 -12 -16 - 1 - 6 -U -15 - 7 -16 - 7 -16 57 54 64 44 56 58 Si 30 23 37 40 20 25 27 35 25 19 - 9 -10 - 9 -23 - 7 -12 -14 -24 -13 -13 -14 -20 -17 -23 -11 -21 -.30 28 3S 44 52 46 go 33 29 34 48 42 29 23 32 10 29 40 41 26 40 42 44 24 26 35 25 33 27 30 31 24 39 It 25 38 42 -10 + S -10 -23 -18 - 8 20 -14 21 -15 22 -10 23 50 < 44 -23 24 54 40 42 50 46 46 4ri 43 25 35 34 39 30 :/ -28 25 -18 26 27 -17 - 6 28 29 JO 31 44 40 38 38 46, 39 10 -10 26 - 9 35 - 5 29 1 -12 1 Means 53.1 50.9 47.1 56.3 46.6 -9.7 40. 4 1 -15. 9 37.7 35.3 33.4 39.0 31.4 -7.6 25.3 -13.7 Highest and lowest readings arc in italics. 88 Table 20". — Monthly .\nd Season.\l Mean.s — Dew-point .a.nd Ensuing Minimum Temperatures, Mather Wis., 1907. • June. July. -Vugust. Septem- October. Means. Upland: ■ Station 1, shelter- Dew-point. 52.9 52.1 49.1 62.3 60.7 55.6 59.1 56.3 54.0 53.1 50.9 47.1 37.7 35.3 33.4 53.0 9p in . 51.1 47.8 Marsh: Station 4, shelter- Dew-point. 54.9 48.6 63.0 54.9 59.4 5:!.l 56.3 46.6 39.0 31.4 54.5 46.9 - 6.3 - 8.1 - 6.3 -9.7 - 7.6 — 7.6 Station 2, 5 inches. exposed- 42.3 -12.6 49.0 -14.0 47.1 -12.3 40.4 -15.9 25.3 -13.7 40.8 Difference —13.7 Dew-point readings at Berlin. — Observations of dew-point and the ensuing minimum air temperature made at Berlin in 1906 confirm the results obtained at Mather. Even though the ah- was saturated in the early evening and dew formed rapidly, the temperature often fell steadily in spite of the large amount of latent heat liberated by the condensation of water vapor into dew, as on the night of September 23-24. Of course the fall in temperature was not so rapid when the humidity was high and the dew was forming fast, but there was, nevertheless, usually a steady fall on clear nights. The moist condition simph^ tended to lower the rate of cooling, and it is probable that the radiation of heat from the dewdrops themselves was great. Aside from reference to the tables compiled from Mather observations, a few comparisons made at Berlm are given below between the dew-point in the evening preceding nights of frost with the ensuing minimum temperature. Dew-point previous evening. Minimum temperature, shelter read- ings. Sta- tion 1. Minimum temperature, 5 inches. Sta- tion 5. September 5 . . . September 14. . September 24. . September 27. . September 28.. September 30. . October 1 Averages 28 29 29 24 28 23 19 47.9 37.9 25.7 In a dry section at some little distance from water and bog land there may be some con- nection between the dew-point and the ensuing minimum temperature. When a high degree of moisture is present in the air as over a moorlaml, and when the temperature falls ra])idly in the evening, as it usually does on clear nights, the point of saturation is reached in a brief period. Fog aver marshes and low temperatures. — Fog, even though light, has been supposed by some to be a preventive of frost, but this is not quite true; in fact, fog may form over a bog on almost am^ clear cool nigiit following a warm day when the soil has been heatetl and the air for some distance above the surface highly cliarged witli water vapor. The rapid radiation from the surface and humid air on a clear night after a warm day carries the temperature below the dew-point, and fog is immediately formed. It is often said that the formation of 89 fog under such conditions indicates a rapid fall in temperature, and cranberry growers are accustomed to look for a frost when on a clear night light fog forms over the moorland. On such nights the radiation of heat from the particles of fog serves even to lower the tempera- ture of the air. Of course, the radiation of heat from the ground is more or less arrested as the fog increases, but it is surprising what little effect fog seems to have in preventing low night minimum temperatures in the bogs. Special observations on critical nights at the Berlin marsh, September, 1906. — Personal observations in the bog at Berlin, 1906, during several nights when low temperatures occurred, convinced the writer that high humidity and even fog have hardly any effect in retarding the fall in temperature. Even when the bog seemed reeking with moisture, the temperature fell steadily. Often during critical nights, observations of special conditions were made nearly every hour in certain portions of the marsh. There was little opportunity for this kind of work until September, as the temperature during the summer was far above the normal. On August 27 the exjiosed minimum temperature at Station 5, in tlie "ferns," at the 5- inch height was 30.5°, while near the surface at the same place the mmimum was 32.2°, and in the shelter at Station 1 it was 45.5°. No frost, however, was observed that morning at any point in the l)og. On the morning of September 5 the minimum temperatures were 28.3° at the 5-inch height and 32° at the surface at Station 5, and 42° in the shelter at Station 1. Again, no hoar frost was observed, although the exposed minimums registered several degrees below the freezing point. The ferns, however, were damaged by tliis low temperature, as they began to wither immediately afterwards, and some slight damage was noted in the neighboring low- lands outside the marsh. Occasionally light frost may occur in the bogs and pass unnoticed, disappearing very early in the morning, and the wiiter has known of several instances where frost was not observed, although damage to vegetation gave evidence of its occurrence. While these minimum temperatures, of course, do not represent the temperature of the air, yet, even if they represent approximately the temperature of the plants and vines, hoar frost might be expected when these readings fell a few degrees below freezing. The first date on which frost was actually observed at Berlin was September 14, under conditions quite similar to those of the 5th. The shelter minimum at Station 1 was 41.3°, while the minimums at the 5-inch height and at the surface at Station 5 were 28. S° and 32.6°, respectivch*. The morning of the 14th was clear, but with fog over the marsh. (Fig. 6.) Light frost was observed first on the wooden car tracks at the intersections where tlie rails had been spliced, but not on the main portions of the track, or on the cross-ties lower down. (Figure 17 sjiows the tracks and cross-ties.) These splices were about 4 inches above the surface of tlie marsh, and afforded a better opportunity for radiation. A jieculiar phenomenon was noticed at Station 5: The maximum and the minimum thermometers at the 5-irich height were found completelg cockered with frozen dewdrops, dew having been deposited sometime during the night, after which the temperev- ture fell to the freezing point. The thermometers resting on the surface were absolutely free from frost or moisture of any hind. This is a most striJcing example of safety at tlie surface and frost and possibly destruction a few inches above. Some frozen dewdrops were also found on the tops of the splices already referred to. Ordinarily, dew formed on vines and other objects at an elevation of a few inches above the ground sooner than at the immediate surface, doubtless because at that elevation there was no direct connection with the warm ground and the radia- tion was freer, the dew-point was more readily reached, rather than because of any difference in the amount of moisture. A light frost occurred at Mather and Cranmoor on September 14, as well as at Berlin, temperatures below freezing being reported in all the Wisconsin bogs. The frost on the 14th would probably have been more severe had the soil been colder; but it was comparatively warm, because of a hot wave of several days jireceding the cool spell. On the 14th considerable differences prevailed between the temperatures on the uplands and m the bogs, as is usual under such conditions. Light frost was again observed at Berlin on September 24, freezing temperatures being recorded at both exposures at Station 5, but the temperatures were not so low at Cranmoor 90 and Mather, tlie sk}' there becoming overcast before midnight. The Berhn marsh was c|iiite wet from recent rains, especially in tlie east poition wliere tlie water was almost up to the surface. The water had been partially (haiiied from llie west portion, but it was still wet, especially on low ground. In tlie liig ditcii near Stations 2, .3, and 4, the water was but 2 to 3 mches below the surface. The sky was ck'ar (kiring the entiie night. About 7 p. m. on the 23d fog was first o])served along the main ditch; after midnight the fog increased and spread over tlic bog, and by 3 a. m. it was very dense. The whole marsh seemed to be reeking with moisture. The relative humidity was 100 per cent continuou.sly after 10 p. m., yet the tempera- ture fell rather uniforndy until I a. m.; then after remaining stationary about an hoiu' it rose gradually. In tlie morning frost was observed on most of the wooden car tracks, especially wliere they were situated away from tlie water. None was observed on the cros.s-ties restmg on the surface of the bog, and while frost was seen generally on the tracks, it was more pro- nounced on tiie edges and on the upper side of the splices covering the joints of the rails, where radiation was freest. In other words, frost was heavier at a shglit elevation on account of freer radiation than at the immediate surface, this being cegan to form liefore sundown. Heavy fog over marsh in evening. Heavy dew in morning; frost obscrird in patches. Heavy dew in morning. Thimderstorm conditions. Heavy dew and dense fog over marsh in early morning. Thunderstorm conditions. Thtinderstorm conditions. Heavy dew and dense fog in morning. Heavy dew and dense fog over marsh in evening. Heavy dew and dense fog over marsh in early morning and again at night. Heavy dew and dense fog over marsh in early morning. Thunderstorm conditions. Do. a In open over bog. Highest and lowest readings are in italics. 102 Table 21. — Daily Weather Conditions, Mather, Wis., 1907 — Continued. jCly. Barometer— Rising (R), falling (F), .sta- tionary (S). Relative humidity. Dew-point, 7 p. m. Rainfall. 7. 8. 9; 10. 29.86-R 30. 10-r 30.10-F 30. 00-S 29.82-S 29.93-R 29.90-F 29.92-S 29.96-S 29.92-F 11 29.84-R 12. 13. 14. 13. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. Means 30.04-S 29.94-F 29.74-S 29.BJ,-F 29.92-S 30. 06-S SO. 12-S 29.94-F 29. 98-S 29.90-F 29. 86-R 29. 98-r 29. 80-S 29.78-F 29. 98-S 30. 04-F 29.84-F 29.92-S 29.98-F 29.92-S 7 p. ni. 29. 98-R 30. 06-S 29.90-S 29.94-F 29.84-R 29.90-R 29.82-R 29. 92-R 29. 90-S 29. 82-S 29. 92-R 30.00-F 29. 80-S 29. 72-S 29. 74-R 29. 88-S SO. lO-S 30. 00-F 29. 90-R 29. 96-R 29. 70-S 29. 96-R 29. 84- F 29. 80-S 29. ee-R 30. 02-S 29. 90-F 29. 76-R 29.94-R 29. 92-S 29.86-F Up- land. 81 72 95 100 98 S3 98 96 S3 98 93 80 76 94 75 85 74 81 74 p. m. Up- land. iS5. M^^h- 90 92 81 86 91 95 100 91 93 91 92 93 76 66 75 89 95 85 62 Marsh. T. 0.35 2.15 .03 .18 .52 .09 .89 .02 T. 7 p. m. T. 0.35 .03 .01 .05 .02 .13 .02 .03 3.89 T. .02 .20 Total. Pre- vail- ing direc- tion. T. 0.70 .03 2.16 .05 .03 .20 .65 .02 .03 .09 4.78 .02 T. .02 T. .20 NW NE' SW SW SE N NW SW NW NW NE NE NW SE SW SW NW SW NW SE W NW S NW SW NW SW NW SW W NW NW NW NW Average ve- locity. Up- land. 11.6 4.5 7.3 5.5 5.9 6.8 5.6 4.5 6.0 4.8 11.4 10.1 10.4 7.5 8.9 5.6 8.2 5.2 7.2 9.0 6.3 7.5 8.8 8.3 5.4 9.6 9.4 8.6 9.2 Marsh. 7.0 1.8 3.7 4.0 2.8 2.7 3.5 2.9 2.0 3.4 1.9 4.8 5.1 5.8 3.6 5.0 2.3 4.5 2.6 3.5 5.2 2.8 4.0 4.9 4.8 2.5 5.2 5.0 4.5 4.8 Direction and ve- locity at time of minimnm tem- perature. Upland. NW 8 N 5 SW 3 SE 2 SE NW W NW NW N NE 3 N 4 Calm. S 4 Calm. S 8 2 SE 12 7 N 4 Calm. NW 5 1 NW 4 Calm. SE 4 Calm. W 6 2 s 4 Calm. NW 5 3 N 3 Calm. SW 5 2 N 2 Calm. N 8 4 W 2 Calm. SW 5 Calm. NW 9 3 NW 4 Calm. NW 8 3 Marsh. Calm. Calm. Calm. Cain Calm. NW 5.0 1.2 o Total. With the exception of a heavy rain on Ihe 5th which kept the water in the ditches high for several days, the condition of the marsh during the first half of the month was nearly normal. A period of showery weather set in on the 14th, culminating in an unusually heavy rain on the 21st, which completely flooded the marsh and raised the water in the reservoir 4 inches above high-water mark. This was further augmented by the breaking down of a dam on the marsh above. Station 7 was covered with water to adepth of nearly 12 inches for three days after the 21st, and the water did not entirely disappear until the 1st of August. Highest and lowest readings are in italics. 103 Table 21. — Daily Weather Conditions, Mather, Wis., 1007 — ('oniinued. JULY. Temperature. Shelter Station 1, Upland. Maxi- mum. 79.7 Mini- mum. Sta- tion 2, inini- mum.a Differ- ence — Mini- mum from mini- mum. 49.0 Previous night. Cloudy Clear Partly cloudy. Clear. Partly cloudy. Cloudy, Clear do Cloudy Partly cloudy. Day. Partly cloudy. Clear Partly cloudy. do do do Clear Partly cloudy. Cloudy do Cloudy ! Partly cloudy. Partly cloudy. do Cloudy do Partly cloudy. Clear Partly cloudy. Cloudy Clear Cloudy Partly cloudy. Clear do Partly cloudy. do ....do Cloudy Clear ....do ...do do do Cloudy do do Clear Cloudy Partly cloudy. do Cloudy Partly cloudy. do Clear Partly cloudy. Clear Cloudy Partly cloudy. Clear Partly cloudy. Clear Per cent of sun- shine. 72 100 59 91 71 40 47 38 100 29 66 84 75 79 100 56 100 57 82 97 80 94 68 Miscellaneous. Heavy dew in evening. (Heavy dew in morning. No frost observed, but light fnisi probably I occurred in portions of marsh Ijefore daybreak. Dense fog in early morning and previous night. Severe thunder- storm conditions in vicinity. Severe thunderstorm in evening with liail and heavy rain, flooding marsh and injuring cranberries. Thunderstorm conditions in morning. Dense fog in early morning, clearing about 2 p. m. Distant thunderstorm in evening. Clearing toward night. Distant lightning in evening. Thunderstorm in early morning. Heavy thunderstorm flooding marsh and reservoir. Distant thunderstorm in evening. Thunderstorm in afternoon. Cloudy in evening. o In open over bog. Highest and lowest readings are in italics. 104 Table 21. — Daily Weather Conditions, Mather, Wis., 1907 — Continued. AUGUST. Barometer — Rising (R), falling (F), sta- tionar.v (S). Relative huniiditv. Dew-point, 7 p. m. Rainfall. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12., 13. 14., 15., 16.. 17.. 18.. 19.. 20.. 21.. 22.. 23.. 24.. 25.. 26.. 27.. 28.. 29.. 30.. 31.. 29. 72-F 29.88-R 30. 04-R 30.06-F 29. 74-R 30.02-F 30. 04-R 30. 16-F 3a08-F 30.00-F «9. 70-S 30. 02-R 30 18-R SO. ess 30.0D-F 29. 80-R 30. 04-S 30. 16-F 29.90-S SO. ess 30. 24-S 30 20-F 29.90-F 29.90-R 30. 04-F 29. 94-S 29. 80-R 30. 04-R 29. 98-S 29. 98-R 30. 14-F 7 p. m. Up- land. S9. 71-S 29. 94-R 30. 04-S 29. 86-F 29. 88-R 29.90-R 30. 06-S 30. 08-S 30. 00-S 29. 84-F 29. 76-R 30. 00-S 30. 20-R 30. 10-S 29. 80- F 29. 88-R 30. 06-R 29. 96-F 30.00-R 30. SS-S 30 14-F 30. 00- F S9. 71-E 29. 92-R 29. 96-F 29. 76-F 29. 92-R 30. 00-S 29. 90-S 30. 00-R 30. 08-S Means 97 90 88 90 97 82 79 90 73 62 88 66 82 76 80 88 64 85 76 69 73 85 78 64 74 91 97 69 69 92 Marsh. r p. m. Up land. Up- land. Marsh, 91 80 90 72 91 92 90 91 89 72 71 77 73 92 88 48 86 82 69 95 79 63 84 70 87 99 89 85 93 86 80 82 Marsh. 51 .01 .10 T. T. .06 T. 1.35 2.28 .37 T. .24 .05 a 4. 97 7 p. m. 0.09 T. .05 T. .54 T. .34 T. .78 T. T. T. Total. Pre- vail- ing direc- tion. 0.60 .01 .10 .05 T. T. .60 T. T. 1.35 2.62 T. .37 .78 T. T. .24 .05 NW NW NW sw w sw NW SE S s sw NW NW SE S SW NW SW SE NW SW SW SW sw NW SE sw w SE NW SE 6 6.77 SW NW Average ve- locity. Up- land. 12.8 9.9 6.3 9.9 11.9 12.8 6.0 8.3 6.2 11.5 12.6 9.4 4.8 7.9 10.8 15.0 5.3 15.9 12.2 7.5 3.8 8.5 12.8 13.5 6.8 7.5 4.4 2.5 5.5 3.2 7.3 7.4 5.9 3.4 4.8 6.5 5.2 3.3 4.1 2.9 5.8 6.6 4.6 2.2 3.5 5.3 8.5 2.2 8.6 6.6 4.0 1.7 3.5 5.7 7.4 3.6 3.6 2.4 1.0 2.5 1.4 3.3 Direction and ve- locity at time of minimum tem- perature. Upland. Marsh. NW 5 NW 10 NW 8 S 3 SW 11 S 5 NW 10 S 3 SE 5 S 6 SW 7 NW 8 NW 11 NE 4 S 10 SW 5 NW 6 SW 6 SE 6 NW 12 SW 2 SW 3 SW 5 SW 10 NW 5 E 10 SW NE SE N E SW NW Calm. Calm. 7 Calm. 4 1 Calm. Calm. 5 Calm. 5 Calm. 2 2 1 Calm. 2 1 Calm. Calm. 1 3 2 1 2 Calm. Calm. 1 Calm. tt Total. Marsh continueii wet and water in the ditches4iigh all of the month. Highest and lowest readings are in italics. 105 Table 21.— Daily Weather Conditions, Mather, Wis., 1907— Continued. AUGUST. Temperature. Shelter Station 1, Upland. Maxi- mum. 68 68 74 79 84 80 76 85 89 80 79 81 85 82 79 85 84 74 66 74 74 78 72 73 84 69 76 68 75 89 Mini- mum. 76.7 Sta- tion 2, mini- mum.a 55 46 48 39 59 54 57 55 54 59 74 53 50 53 56 61 52 57 65 43 47 43 54 54 ^8 51 56 58 51 64 58 Differ- ence — Mini- mum from mini- mum. 47 39 40 34 58 46 43 51 49 55 70 40 42 46 50 58 43 48 65 34 36 34 47 41 SS 42 56 50 44 62 52 Weather. Previous night. Day. Partly cloudy. Cloudy Clear Cloudy do : Partly cloudy. Clear Partly cloudy. Cloudy Partly cloudy Cloudy Clear do Partly cloudy. Clear Partly cloudy Clear do Cloudy Clear Partly cloudy. Clear Partly cloudy. do Clear Partly cloudy. Cloudy Clear Partly cloudy Cloudy do Per cent ot sun- shine. Miscellaneous. Partly cloudy, do do do Clear Partly cloudy. Clear Cloudy Clear do Partly cloudy. Clear do do Partly cloudy Clear do do Partly cloudy Clear ....do ....do Partly cloudy. do Clear Cloudy Partly cloudy Clear Cloudy Partly cloudy Clear 49 55 90 69 90 47 94 18 90 83 48 100 95 80 84 100 100 100 49 100 91 91 92 92 95 10 36 100 4 50 85 Thunderstorm in early morning. Dense fog over marsh in evening. Thunderstorm conditions. Cloudy late in the evening. Heavv thunderstorm in morning. Moderately heavy dew in morning. Thunderstorm in evening. Light dew in morning. Moderately heavy dew in morning. Thunderstorm conditions. Dew ijegan before sunset; fog over marsli in evening. Cloudy at mid- night. Fog appeared over marsh at sunset. Heavy ground fog over marsh at 5 a. m. Thunderstorm. a In open over bog. Highest and lowest readings are in italics. 106 Table 21. — Daily Weather Conditions, Mather, Wis.. 1907 — Continued. SEPTEMBER. 1., 2.. 3., 4.. 5.. 6.. 7., 8.. 9.. 10.. 11. 12. 13. 14. 15. 16., 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. Barometer — Rising (R), falling (F), stationary (S). Means.' 7 a. m. 30. 02-S 29.90-F 29.80-S 29.90-S 30. 08-S 30. 08- F 29. 78-r 29.82-S 30. 02-R 30. 04-S 29.94-R 30. 12-R 30. 14-R 30.00-S 30. 08-E 30.00-S 30. 04-S 30. 04-F 29. 92-F 29. 78-R 30.0O-S 30.08-F S9.i8-F 29.58-R 30.26-R 30. 20-S 30.00-S 29.88-S 30. 02-S SO. ss-s Relative humidity. Up- land. 29.90-R 29.86-S 29. 84-S 29. 92-R 30.06-S 29.94-F 29. 8b-R 29. 92-R 30. 08-R 29.96-F 29.98-R 30. 12-S 30. 00-S 30.00-R 30. 10-F 30. 04-R 29.98-F 29. 92-F 29. 72-F 29.98-R 30. 06-S 29. 76- F 29. S6-R 30. 02-R 30.26-F 30.08-F 29.90-S 29.96-S 30. 06-R 30.S0-F Marsh. S. M^^h. 91 92 80 76 76 68 96 97 97 95 94 81 77 95 81 87 83 94 74 72 74 Dewpoiut, 7 p. m. Up- land. 85 Marsh. 52 55 T. 0.01 .31 .27 .14 .01 .25 .40 .41 .10 7 p. m. O1.90 0.01 .03 .04 T. .01 T. .75 T. T. .14 T. .02 ol.OO Total. T. 0.02 .03 .04 .31 .27 .01 T. .14 .76 .25 .40 .41 T, .24 T. .02 2.90 Pre- vail- ing, direc- tion. NW NW NW NW NW W E NW NW NW NW sw SE sw SW SW NE SW NE W SW SW W NW w SW NE NE NW S NW -Average ve- locity. Up- land. 11.1 11.0 8.0 9.1 7.8 4.0 5.6 9.5 9.3 3.2 10.8 7.4 14.4 14.5 10.4 10.1 11.5 10.2 14.0 14.6 13.1 18.8 13.3 19.5 8.1 8.2 10.2 7.9 7.5 5.1 Marsh. 9.9 6.2 6.2 4.5 5.3 4.0 l.S 5.2 5.1 1.1 5.6 816 7.2 5.9 4.5 5.0 5.8 4.7 6.8 8.2 6.9 4.0 7.3 11.4 4.3 3.1 4.8 3.6 4.1 2.0 5.0 Direction and ve- locity at time of minimum tem- perature. Upland. NW 8 NW 9 NW 6 NW 10 NW 12 SW 2 E NW NW N NW W SW sw w sw 13 SW 5 S 4 NE 6 NW 17 SW 4 SW 4 W 10 NW 30 W 6 SW 4 NE 3 NE 9 S 1 W 3 Marsh. Calm. 3 Calm. 1 Calm. Calm. 4 1 4 2 2 3 13 1 1. 1 10 3 1 Calm. 5 Calm. NW 7. 7 2.8 a Total. Marsh continued wet and water in ditches high all of I he month, flooding in anticipation of frost l^.'ing frequent during latter part of the month. Highest and lowest readings are in italics. 107 Table 21. — Daily Weather Conditions, Mather, Wis.. 1907 — Continued. SEPTEMBER. Temperature. Shelter Station 1, Upland. Maxi- mum. 68 65 06 71 67 64 65 68 64 73 78 80 82 Si 81 74 79 Si 66 62 64 62 i9 55 63 55 60 60 61 68.3 Mini- mum. TO 53 50 52 44 41 54 56 40 38 45 48 50 62 63 67 53 58 61 60 38 31 45 43 es 34 34 37 29 2S .Sta- tion 2, miui- inum.a Difler- ence — mini- mum from mini- mum. 61 42 40 45 36 33 55 56 30 30 37 37 40 57 54 6i 44 56 58 57 30 23 37 40 20 25 27 35 25 19 40.4 - 9 -11 -10 - 7 - S - 8 + 1 -10 - 8 - 8 -// -10 - 5 - 9 - 3 - 9 _ 2 - 3 - 3 Previous night. Partly cloudy. ....do ....do Cloudy riear Partly cloudy Clear do Partly cloudy do Clear Cloudy I Cloudy ....do Clear Partly cloudy. . ...do Clear Partly cloudy. Clear do Cloudy Partly cloudy Cloudy do do Partly cloudy Clear Cloudy do Clear Partly cloudy ....do Partly cloudy. Clear Cloudy Partly cloudy Clear do do Partly cloudy. Clear Cloudy Partly cloudy, do Clear Partly cloudy do Per cent of sun- shine. Miscellaneous. Cloudy do Clear Partly cloudy Cloudy Cloudy do I Partly cloudy Partly doudy. Cloudy Clear Partly cloudy 94 100 41 60 1 50 100 24 60 72 100 93 88 85 31 46 63 72 70 70 18 21 100 38 33 86 Cloudy in evening. Fog began to form about 8 p. m. Fog quite dense in morning, especially over marshes; grass very wet from dew and fog. Dew began to form at 6 p. m.; light fog over marsh in evening. Although minimum temperature was low, no frost was observed. Increasing cloudiness in afternoon. Thunderstorm in morning. Do. Thunderstorm conditions. Thunderstorm in early morning. ■ I Killing frost in morning; frost first oliserved last night at 10.30 on marsh. Clearing at night. Killing frost. Do. Ligtit frost. Ground fog on marsh after 5.45 p. m. Killing frost . Killing frost , ifry lifaiy deposit. a In open over bog. Highest and lowest readings are in italics. 108 Table 21. — Daily Weather Conditions, Mather, Wis., 1907 — Continued. OCTOBER. Barometer — Rising (Rj, falling (F), stationary (S). Relative humidity. Dewpoint, 7 p. ni. Rainfall. Wind. ( p. m. Up- land. Up- land. Up- land. Marsh, Marsh. 7 p. m. Total. Pre- vail- ing direc- tion. Average ve- locity. Up- land. Marsh. Direction and ve- locity at time of minimum tem- perature. Upland. Marsh. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. U. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 30. is-r 29.86-R 29.86-S 29. 96-S 29.98-R 29.80-F S9. 60-R 30.22-S 29.90-S 29.84-F 30.0O-E 30.28-S SO. U-R 30.28-F 30. I2-S 30. 16-S 30. 08-F 30.42-S 30.28-F 30.20-R I 30.42-F j 29.90-F 30. 14-S 30. ll-F 30. 22-R 30. 22-F 29.94-R 30. 30-F 30. 16-S 30. 26-R 30. 26-F 29.86-F 29.90-S 29.80-R 29.88-S 30.0O-F B9.e0-F 29.94-R 30. 10-F 29.98-S 29.86-S 30. 14-R 30. 32-S 30.32-F 30. 12-S 30. 14-S 30. 12-S 30. 10-R S0.40-F 30.04-F 30. 36-S 30. 10-F 29.94-R 30. 18-S 29.98-R 30. 32-S 29.90-F 30. 26-R 30. 18-S 30.22-S 30. 30-F 30. 14-F 85 60 86 75 60 86 84 53 63 82 44 87 82 85 87 87 76 77 81 64 61 84 88 97 56 0.04 .09 .01 .02 .03 .10 T. T, T. .10 0.08 .01 .06 T. T. T. T. T. T. T. T. .05 0.08 .04 .10 .01 .08 T. .03 T. .10 T. T. T. T. T. .05 .10 SE sw sw w NW SW NW SW NW NW NW NW NW SW SW SW SW NW SW N SW W SW SW N SW NW SW E SE SE 13.0 5.7 7.6 8.6 7.9 14.4 11.4 8.7 15.9 16.2 14.0 10.2 5.6 7.8 8.0 5.4 13.7 8.8 5.6 6.9 10.6 11.7 5.4 11.5 7.7 8.0 14.7 6.1 8.7 9.5 6.5 2.2 4.0 4.4 3.7 6.5 6.5 3.8 8.1 8.9 8.4 6.1 2.5 3.2 3.8 1.9 6.9 4.8 2.6 3.7 4.0 5.7 2.1 5.7 3.9 3.4 8.7 2.4 4.1 4.6 SE 5 SW 6 NE 7 W 5 NW 6 NW 6 NW 12 SW 4 NW 9 NW 3 NW 10 NW 12 NW 4 SW SE SW NW NW NW NE 9 SW 3 NW 8 SE 6 S 6 NW 8 NW 6 NW 17 SW 4 NE 5 SE 7 E 6 2 1 Calm. 2 2 1 2 1 4 1 7 7 3 Calm. 4 Calm. Calm. 7 1 4 1 4 1 3 3 1 2 Calm. 2 3 2 Means. 81 66 38 11.20 a. 59 SW 4.8 NW 6.6 2.3 a Total. Marsh was much drier this month than at any time previous this season, except in the latter part of June, although water in the ditches remained high until about the 10th of the month. Highest and lowest readings are in italics. 109 Table 21. — Daily Weather Conditions, Mather. Wis., 1907 — Continued. OCTOBER. Temperature. Shelter Station 1, Upland. Maxi- mum. Mini- mum. Sta- tion 2, mini- mum a. 25.3 Differ- ence — mini- mum from mini- mum. - 7 -10 -U -U -10 -13 - 7 - 7 -10 - 9 - 6 - 9 - 6 - 5 - 7 -12 - 6 - 9 - 6 - 6 - 9 - 8 -U -11 - 7 Previous night. Partly cloudy. Cloudy Partly cloudy. do Clear Partly cloudy, do Clear Cloudy Partly cloudy. do Cloudy Clear do Cloudy Partly cloudy. Clear do Day. Cloudy Partly cloudy. Cloudy Partly cloudy. Clear do Cloudy Partly cloudy. Cloudy Clear Cloudy do Clear Partly cloudy. do do Clear do Partly cloudy. Cloudy.. do Clear Clear [ do.. Partly cloudy. [ do. . do do.. ....do ....do Partly cloudy. do Clear Partly cloudy. Cloudy I Cloudy Partly cloudy. Clear,. Clear Cloudy Cloudy do. do i do. Per cent of sun- shine. 21 65 IS 70 83 85 75 72 11 13 100 70 100 100 100 83 98 86 100 69 100 34 10 44 38 Miscellaneous. No frost or dew observed. Lightfrost. Do. Heavy and killing frost; looked like light, snow; thin ice formed. No frost ol)Serve(l. Heavy and kilting frost; ice formed. Killing frost and ice; aurora in evening. Killing and heavy frost and ice. Dense fog from last midnight until 11 a. m. Light fog in evening over marsh. Killing frost, light in amount, but damp ground froze. First snow flurry of the season; severe freeze. Freezing. Very heavy deposit of frost. Ice on reservoir. Frost. Freezing. Frost. Heavy frost in morning. Snow in morning. Exceedingly heavy frost deposit. a In open over bog. Highest and lowest readings are in italics. 110 Comparison between temperatures in the bog at Mather, Wis., and at United States Weather Bureau Office, La Crosse, Wis. — While numerous references liave been made to the mininiuni tAiiperature readings at La Crosse, a more complete comparison between the temperature at that place and Mather should be of interest, especially to those who are well acquainted with the daily weather map. Forecasters must look to the forecast chart for their general information, and many of them are accustomed to consider reports from certain stations as " keys" to conditions prevailing in adjacent sections. La Crosse may be considered as a "key" to the cranberry mareh region of Wisconsin. It is situated about55 miles southwestof Mather, and is an old established station of the Weather Bureau. The thermometers at La Crosse were at the time of this investigation located in an instrument shelter on the roof of the federal building. Thus far the study has been confined mainly to the temperature conditions in the bogs, showing the witle range in even the same bog; and references have been made to the general weather conditions prevail- ing as shown by the daily weather maps. Some mention has also been made of the tem- ])erature readings at La Crosse in connection with the marsh readings in Wisconsin, and now a comparison of observations of temperature at both La Crosse and Mather for the entire season of 1907, Tables 22 and 22a should prove interesting. The maximum temperature readings are not included in the table, as a comparison of them does not seem to be important. The minimum shelter readings at Station 1 at Mather averaged 5.2° lower than at La Crosse (Table 22a), and the average diflference was greatest in June, 7.1°, and least in September, 3.6°. The temperature in the shelter over the mosd at Station 2 on the bog averaged 8.7° lower than at La Crosse, and the greatest monthly difference was again in June, 10.8°, and the least in September, 6.4°. The minimum exposed over the moss at the height of 5 inches on the bog averaged 11.9° lower than at La Crosse, and the greatest jnonthly difference was in June, 13.9°, and the least in May, 8.5°. The minimum in the open on the bog at Mather averaged 3.2° lower than that in the shelter nearby. The greatest difference on any one day in the various months between the temperature at La Crosse antl that in the open over the moss at Mather was 20° in May, 24° in June, 21° in July, 19° in August, 20° in September, and 22° in October. Often there were days of very little difference when the weather was cloudy, and there were a few instances where the temperature in the bog at Mather was even higher than at La Crosse. This is not surprising in view of the fact that these stations are 55 miles apart, and that occasion- ally the weather conditions at the two places differ considerably. What we should consider in the study of these readings is the average difference under all conditions, the average difference when the pressure is high and the weather clear, and the extreme differences. While extreme differences of 22 to 24 degrees maj- occur, there are usualty days in every month when the tem- peratui-e in the bog is 20° lower than at La Crosse. The average difference when the weather is clear and the pressure high is about 18°, so that when the temperature at La Crosse is 50° during the conditions favorable for frost, it is probable that the temperature at the coldest places on the bog is as low as 32°. The latter has reference, however, to the reading of a minimum thermometer in the open, and ordinarily, the reading of the exposed minimum at the coldest point in the bog must be below 30° to cause any damage. On August 8, 1904, when the mini- mum temperature at La Crosse was 48°, the memorable midsununer freeze occurred which destroyed the greater portion of the Wisconsin crop, minimum temperatures in the bogs being as low as 26°. Frost usually formed on the thermograph before it did on the vegetation, indicating that the black metal cover of the instrument loses heat even uiore rapidly than the vines and grasses. Again, temperatures of 30°, 29°, and even 28° have been observed when no frost was seen, but unless frost is looked for on such mornings at the ver}^ time of minimum temperature, there is no proof that frost did not occur. When the temperature is below freezing for a brief period only, light frost may form for a few minutes just before daybreak, and disappear as soon as the temperature rises to the melting point. Even should frost occur during any night in summer, the temperature would have risen above the freezing point by sunrise. Ill -MixiMUM Temperatures at Weather Bureau, La Crosse, Wis., and at Different Locations at Mather, Wis., Season of 1907. May. Day of month. 8.. 9. 10. 11. 12. 13. 14. 15. le. 17. 18. 19. 20. 21. 22. 23. 24., 25.. 26.. 27.. 28.. 29.. 30.. 31.. Readings from Weather j Bureau olTice , i La Crosse,; Wis. I Shelter on vipland, Mather. Wi.s. Shelter on marsh, over moss, Mather, Wis. Read- ings. 1 : 2 3 - -..' 4 6 ' Means. Ditler- ence. Read- ings. Differ- ence. At 5 inches above marsh, over moss, in open, Mather, Wis. Read- ings. + S + 4 - 2 -10 -li - 1 - 3 - (5 - 3 + 3 - 40.9 -3.8 38.1 - 8 -I- S + 4 _ 2 -15 -15 - 9 -12 -18 - 2 - 3 - 8 - 3 + S ~~ 7 -10 -16 -14 - 4 -6.6 Differ- ence. 35 { eo 45 36 34 32 \ 32 28 la 21 44 44 40 44 45 27 27 30 36 45 36.2 -10 + 4 + 4 - 3 -18 -18 -14 -15 -20 - 2 - 3 -10 - 4 -I- 6 -11 -14 -SO -17 - 5 June. Readings from Weather Bureau office. Lacrosse, Wis. 56.2 Shelter on upland. Mather,' Wis. Shelter on marsh, over moss, Mather, Wis. Read- ings. Differ- ence. - 5 -12 - 2 -12 -n - 4 -10 - 1 - 5 -11 -12 -U -1- 2 - 6 _ 2 - 7 -10 - 5 - o - 6 - 7 -13 -11 - 6 49. 1 -7. 1 Read- ings. Differ- ence. At 5 inches above marsh, over moss, in open, Mather, Wis. Read- ings. 45.4 ! -10.8 Differ- ence. -17 -18 o -13 — n -18 — 5 -211 -a — 5 -18 — 4 —15 -Ul —20 -19 — 5 — 1,"> -12 —IB -18 -12 -12 -10 -13 -17 -19 -19 Note.— Columns headed " Difference " have in every case reference to the readings at the La Crosse office as compared with readings at the various exposures at Mather. Highest and lowest readings are in italics. 51936°— Bull. T— 10 S 112 Table 22. — Minimum Temperatures at Weather Bureau, La Crosse, Wis., and at Different Loj^tioxs at Mather, Wis., Season of 1907— Continued. July. August. Day of moil th. Readings from Weather Bureau office, La Crosse, Wis. Shelter on upland, Mather, Wis. Shelter on marsh, over moss, Mather, Wis. .\t 5 inches above marsh, over moss, in open, Mather, Wis. Readings from Weather Bureau office, Lacrosse, Wis. Shelter on upland, Mather, Wis. Shelter on marsh, over moss, Mather, Wis. At 5 inches above marsh, over moss, in open, Mather, Wis. Read- ings. Differ- ence. Read- ings. Differ- ence. Read- ings. Differ- ence. Read- ings. Differ- ence. Read- ings. Differ- ence. Read- ings. Differ- ence. 1 58 60 59 65 70 64 61 65 64 60 62 59 63 63 66 62 61 60 67 64 66 66 60 69 65 58 57 63 61 57 62 59 S8 48 51 60 58 SI 59 61 50 60 51 54 62 6S 51 57 50 56 61 64 64 53 64 63 49 45 59 57 53 58 -1- 1 -12 -11 -H -10 - 6 -10 - 6 - 3 -10 - 2 - 8 - 9 - 1 + S -11 - 4 -10 -11 - 3 - 2 - 2 - 7 - 5 -12 - 9 -12 - 4 - 4 - 4 - 4 55 3« 41 47 61 55 46 50 54 45 60 44 47 61 68 49 48 47 53 53 62 60 54 61 53 46 45 57 51 46 53 ° - 3 -18 -18 -18 - 9 - 9 -15 -15 -10 -15 - 2 -15 -16 - 2 4- S -13 -13 -13 -14 -11 - 4 - 6 - 6 - 8 -12 -12 -12 - 6 -10 —11 - 9 52 19 38 45 59 53 43 47 51 42 60 42 44 56 - 6 -11 -SI -20 -11 -11 -18 -18 -13 -18 - 2 -17 -19 - 7 53 52 51 60 63 64 61 63 62 S9 63 58 60 62 64 64 58 66 58 50 52 51 61 57 52 59 60 60 61 66 89 55 46 48 89 59 54 57 55 54 59 74 53 50 53 56 61 52 57 65 43 47 43 54 64 48 51 56 58 51 64 58 + 2 - 6 - 3 -11 - 4 -10 - 4 - 8 - 8 -10 + 11 - 5 -10 - 9 - 8 - 3 - 6 - 9 -1- 7 - 7 - 5 - 8 - 7 - 3 - 4 - 8 - 4 - 2 -10 - 2 -II 52 43 43 36 59 48 51 53 52 57 72 43 46 49 54 59 47 51 65 39 40 38 51 45 38 46 55 54 48 64 55 - 1 - 9 - 8 -14 - 4 -16 -10 -10 -10 -12 -1- 9 -15 -14 -13 -10 - 5 -11 -15 + 7 -11 -12 -13 -10 -12 -14 -13 - 5 - 6 -13 - 2 -14 47 39 40 34 58 46 ' 48 51 49 55 70 40 42 46 50 58 43 48 65 34 36 34 47 41 S3 42 56 SO - 6 2 -13 3 -11 4 -16 6 - 5 6 -18 7 -13 8 -12 9 -13 10 -14 11 + 7 12 -18 13 -18 14 -16 15 es + g -14 16 46 45 44 -16 -16 -16 - 6 17 -15 18 .. -18 19 52 -15 50 -14 + 7 20 -16 21 60 57 50 59 49 42 41 55 48 45 48 - 6 - 9 -10 -10 -16 -16 -16 - 8 -13 -12 -14 -16 22 -17 23 -14 24 -16 25 -19 26 -17 27 - 4 28 -10 29 44 1 -17 30 62 1 - 4 31 52 j -17 Means 62.2 55.6 -6.6 51.7 -10.5 49.0 -13.2 59.3 54.0 -5.3 50.1 -9.2 47.1 ! -12.2 Note.— Columns headed " Difference" have in every case reference to the readings at the La Crosse oflBce as compared with readings at the various exposures at Mather. Highest and lowest readings are in italics. 113 Table 22.— Minimum Temperatures at Weather Bureau, La Crosse, Wis., and at Different Locations at Mather, Wis., Season of 1907 — Continued. Day of month September. October. Readings from Weather Bureau olEce, Lacrosse, Wis. Shelter on upland, Mather, Wis. Read- ings. Differ- ence. Shelter on marsh, over niosSj Mather, Wis. Read- ings. Differ- ence. At 5 inches above marsh, over moss, in open, Mather, Wis. Read- ings. Differ- ence. Readings from Weather Bureau office. La Crosse, Wis. Shelter on upland, Mather, Wis. Read- ings. Differ- ence. Shelter on marsh, over moss, Mather, Wis. Read- ings. Differ- ence. At 5 inches above marsh, over moss, in open, Mather, Wis. Read- ings. Differ- ence. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 10. 17. 18.. 19., 20.. 21.. 22.. 23.. 24.. 25.. 26.. 27.. 2S.. 29.. 30.. 31.- Means- 50.7 70 53 50 52 44 41 54 56 40 38 45 48 50 62 63 67 53 58 61 60 38 31 45 43 S8 34 34 37 29 18 47.1 -I- 8 - 2 - 6 - 1 - 6 - 9 - 5 + 9 - 5 - 8 - 4 - 4 -10 - 2 - 3 -I- 4 - 8 '-4 - 5 +10 - 4 - 7 - 2 -I- 3 - 5 -;/ -3.6 44.3 + 3 - 9 -12 - 3 -I- 9 - 9 -10 - 7 -12 -16 - 5 - 8 -I- 3 -13 - 4 - 5 + 9 - 7 - 9 - 4 -I- 3 - 8 -16 -10 - 4 -U -11 - 1 -13 -16 - 8 -14 -17 - 4 -I- 9 -15 -16 -12 -15 -SO - 7 -12 + 1 -17 -I- 7 -12 -15 -10 -13 -eo -15 - 8 -15 -17 -6.4 38.2 33 52 46 41 41 44 50 23 40 35 35 29 25 22 44 36 39 24 27 28 19 40 30 29 28 19 34 17 32 37 37 33.4 -16 - 3 - 7 - 3 - 4 -II + 10 - 9 - 5 - 4 - 4 -12 - 3 - 5 - 4 - 9 - 2 - 4 -11 - 2 -10 -I- 9 - 5 -10 - 4 + 2 -17 - 6 -13 -12 -12 -16 -I- 1 -11 - 1 -11 - 7 - 5 - 4 -14 - 4 -10 -14 - 9 - 9 - 5 -10 - 7 - 7 -17 - 6 -11 -I- 7 - 6 -13 - 5 - 1 -4.1 29.9 -8.3 -10 -17 -17 -IS -21 - 3 -16 - 7 -15 -13 -10 - 9 -18 - 8 -15 -17 -14 -14 -10 -15 -11 -12 -12 -13 -17 + 4 -12 -16 - 6 - 5 -12.9 Highest and lowest readings are in italics. Table 22a. — Monthly and Seasonal Means of Minimum Temperatures at Weather Bureau, La Crosse, Wis., AND AT Different Locations at Mather, Wis., together with Differences between the Readings, 1907. Maya June July -Vugust September. . October Means , Shelter on upland, Readings, Mather, Wis. La Crosse, Wis. 44.7 .56.2 62,2 59.3 60.7 38.2 51.9 Readings. Difference. 40.9 49.1 55.6 54,0 47.1 33.4 46.7 -3.8 -7.1 -6.6 -5.3 -3,6 -4,8 -5.2 Shelter on marsh, over moss, Mather, Wis. Readings. Difference. 38.1 45.4 51,7 50.1 44.3 29,9 43.2 -6,6 -10.8 -10,5 -9.2 -6.4 -8,3 8.7 At 5 inches above marsh, over moss, in open. Readings. Difference. 36.2 42.3 49.0 47.1 40,4 25.3 40.0 - 8.5 -13.9 -13.2 -12.2 -10,3 -12.9 -11,9 o Means for twenty days. Note.— Columns headed "Difference" have in every case reference lo the readings at the La Crosse office as compared with readings at the various exposures at Mather. 114 Temperature conditions in the bogs during the seasons of 1908 and 1909. — The principa4features of the season of 190S in the Wisconsin bogs were as follows: Frost occurred on June 11 and 15 at both Cranmoor and Mather, the exposed minimums in the bog at the latter station being 29°, and 28.9°, respectively; frost was again noted at both stations on August 20, 23, and 24; and again in September on the 2d and the 8d, the rest of the month being warm until the 28th when kill- ing frost occurred; also on tlie 29th and 30th. There was ample water supply in the Wis- consin bogs for reflowing, and no ilamage, as a consequence, occurred to the crops from these frosts. In 1909, frost occurred at Mather, June 15 ami 18, but no frost was reported at Cranmoor on any date in June. Frost was again reported at Mather on July 19, when the lowest exposed minimum was 29°. On that date the lowest temperature at Cranmoor was 32.8°, but no frost was observed. On August 30, frost was observed at Mather, but none at Cranmoor, the minimum at Mather registering 23°. The temperature was unusually low in the bogs during September, in strong contrast to the September of 1908, frost being reported on 11 dates at both Mather and Cranmoor. On these days the exposed minimums over moss at Mather were as follows : September 25 14 September 26 13 September 27 12 September 28 26 September 30 22 September 1 ■. IS September 2 16 September 6 22 September 16 24 September 23 24 September 24 22 These conditions were most extraordinary, and following, as they did, a season of compara- tive drouth, the growers were unable to properly reflow their marshes. In fact the larger portion of the Wisconsin crop was destroyed by the frosts of September 1 and 2, 1909, not more than 25 per cent of the entire crop being eventually saved. The conditions as shown by the weather map indicated ])lainly the coming of the frosts during the year 1909, and ample warnings were issued from the forecast center at Chicago. It is unfortunate that water supply was not available for reflowing, as in previous j^ears. The season of 1909 in the moorland sections was the driest in about a dozen years, while in the few years immediately preceding, there was complaint of too nuich rainfall lather than of too little. Temperature of the water in fJie reservoir. — Much has been said already about the low tem- perature prevailing over damp ground, and it has been shown that over a saturated soil the minimum temperature, especially on clear, cool nights is low. It ma}' therefore seem strange that additional water is used in order to ward ofT frost. A reser^'oir usuallj- has about three times the acreage of the bog that it is intended to flow or reflow. The time required to flow a marsh depends upon the head of water at the main gate of the reservoir, afid upon the depth of the water already in the ditches. If the ditches are nearly empt}-, much time is requireil, but the Wisconsin growers usually have water in their ditches up to within about a foot of the surface of the marsh. Through cai)illarity this water rises through the peat, ami if the water is within 6 inches of the top of the ditches the marsh is very wet. By pressing down upon the soil along the edge of the ditches, even though the water therein is considerabl}' below the surface of the marsh, the water is squeezed out as from a sponge. During a dry, warm season, growers are accustomed to let the water remain low in the ditches, in order to save their supply, but as cold weather approaches it is the custom to turn on additional water from the reser- voir. It is often possible to reflow an entire marsh in from two to four hours. The water in the reservoir is usually comparatively warm, and although it loses heat as it passes through the ditches on a cool night, light frost is sometimes avoided by merely increasing the depth of the water in the ditches. At other times, however, the water is raised just to the surface of the marsh, and only when a severe frost is expected are the vines and berries completeh' covered with water. The water turned onto the marsh on these occasions in anticipation of frost usually 115 has a high temperature as compared with the water that is found from day to day in the peat soil of the bog. This latter partakes of the temperature of the soil itself, and is one of the important factors in preventing the heating of that very soil in the daytime, and consequently one of the direct causes of the low minimum air temperatures at night. If the water is low in the reservoir, as happens during a drought, and during a cool period its temperature is reduced, nothing can be gained by flowing unless there is sufficient supply to completely cover the bog. To bring this cold water just to the surface would be to reduce the temperature of the air still further by evaporation. Reference has already been made to the drouth in the Wisconsin bogs in the summer of 1909. Few growers had sufficient water supply to reflow in anticipation of the severe frosts of September 1 and 2 of that year, and it has been said that the growers who did not attempt to reflow suffered less injury than those who used their limited supply of water, chilled as it must have been. While, as has been stated before, in order to be effective, the acreage of the reservoir should be three times that of the cranberry marsh, the reservoir of the Fitch marsh at Berlin was hardly half the size. There are other marshes in Berlin that have no protection in the shape of reservoirs. The Sackett. marsh depends upon the Fox River for its water supplj^, the water being pumped from the river whenever there is need of flowing or reflowing. A Richard soil thermograph placed in the reservoir at the Appleton marsh, with its bulb about 12 mches below the surface, has furnished an interesting sei'ies of readings of water tem- perature for the season of 1907. (Fig. 14.) The temperature of the water responded to the varying changes in the temperature of the air. There was an irregidar increase through June and July to the middle of August, the highest maxunum occurring on August 7, 79°, with the exception of a maxunum of 81° which occurred on June 17 and 24, during and following a protracted period of high temperature. The highest minimum, 73°, occurred on June 22 and August 11. The highest and the lowest temperatures each month were respectively as follows: May, 67° and 42°; June, 81° and 53°; July, 77° and 66°; August 79° and 58°; Sep- tember, 70° and 46°; October, 60° and 35°. The absolute range for the season was therefore 46°. The following are the mean daily maximum and minmium temperatures each month: May, 58° and 49°; June, 70° and 63°; July, 74° and 69°; August, 70° and 64°; September, 61° and 55°; October, 49° and 42°. Throughout the season, the lowest temperature of the day usually occurred at about 5 a. m. and 6 a. m. The maximum occurred in May at 4 p. m., and as the season advanced it occurred later and later each day until midsummer, after which it gradually occurred earliei' in the afternoon, so that in October the time of maximum was 2 p. m. The greatest daily range in the temperature of the water was 16° on June 1, and there were a number of days when the temperature varied only 2° or 3°, during cloudy weather. The lowest temperature in October, 35°, occurred on the night of the 27th-28th. Figures 26 and 27, previously referred to, show the relation existing between the temperature of the water in the reservoir and the temperature of the air and of the soil at Mather, Wis., for two selected weeks in 1906. Observations were not made regularlj' of the temperature of the water in the ditches, but there is no doubt that on clear, cool nights it was much lower than that in the resei-voir, as the latter had considerably less volume and lay in the midst of the cold bog. Observations made at Berlin on October 1, 1906, showed a temperature of 53° m the reservoir, and temperatures of 37° and 39° in two small ditches. The ditches at Berlin where these observations were taken were shallow, the water being scarcely more thai> a foot in depth. At Mather, on the other hand, the ditches were 3 feet in depth, and they were consequently able to carry a con- siderable volume of water. While the water turned on from the reservoir into the ditches gradually loses heat, it, in turn, communicates heat to the marsh even before the surface of the marsh is covered. The thermograph sheet shows several instances when, after the water had been turned on, not only the fall in temperature over the bog was ari-ested, but a rise actually occurred for a brief periotl, although this was followed again by a fall. The thermograph sheet, at Station 3, in the open 116 for June 5-6, 1907, shows this graphically. (Fig. 30.) At about 10 p. m. the temperature had fallen to 37°; during the next two hours an irregular curve was described. At midnight the temperature had risen to 42°, after which it gradually fell. On the same night, the ther- mograph trace of the instrument at Station 5, on the bog, shows that from 10 p. m. until nearl}^ midnight the fall in temperature was retarded somewhat. (Fig. 30.) The water in reflo wing was colder upon reaching Station 5, as it was farther away from the reservoir than Station 3 ; moreover, on the night of June .5, the water was not so high in the section around Station 5 as around Station 3, on account of the slight difference in elevation of the two stations. The lowest temperature at Station 3 was 33°, while at Station 5 it was 32°. At Station 2, over moss and outside the cranberry marsh where flooding was not practiced, the minimum tem- perature was 28°. The temperatures at Stations 2 and 5 as a rule differed but little, as stated 5th noon mdi JUNE, 1907. 6th 5th noon noon mdi noon Fig. 30. Station 3 Station 5 Thermograph trace in "open " over bog from noon. .June 5, 1907, to noon, June 6, 1907, showing effect of flow- ing of marsh on temperature of air. Stations 3 and .5, Mather, Wis. before, the average difference between the exposed minimums at the 5-inch height for the entire season of 1907 being but 0.1°. It is therefore probable that reflowing the marsh on this night was responsible for the difference in temperature of 4° between Stations 2 and 5. CONCLUSION. Advantages gained from sanding, draining, and cultivating. — It is obvious from a study of the obser\^ations presented in the foregoing tables that sanding, draining and cultivating seiwe to decidedly modify low night air temperatures; and it is strange, at first thought, that Wis- consin growers do not sand their marshes. Many of them, however, object to the use of sand on the ground that the natural peat soil produces cranberries of better quality. Again, as previously stated, gravelly sand, such as is used on Cape Cod, is not available in the moorland region of Wisconsin, and ordinary fine sand packs too closely and permits a rank growth of vegetation. The Wisconsin grower states that he can secure better returns financially by using his money in extending his marsh rather than in sanding it, because there are vast areas in Wisconsin available for cranberry culture as compared with the restricted region of Cape Cod; and that if the vines are planted in sand, the cost of preparing the bog for planting 117 is doubled, without doubling the returns as a result; but this statement is not accepted by Professor Whitson and his assistants connected with the experiment station at Cranmoor. As a matter of fact, the average .yield per acre in Cape Cod is 40 barrels; in New Jersey, 30 barrels; and in Wisconsin, only 20 barrels. There are even authentic reports of 200 barrels per acre raised on Cape Cod under most favorable circumstances. It is not denied, however, that sanding is valuable in warding of frost, and the fact that reflowing is seldom required at the experiment station where intensive farming is practiced is, of itself, of the greatest impor- tance. Sanding is obviously needed far more in Wisconsin than in Massachusetts, because the temperature averages much lower in Wisconsin, as has been shown in the introduction of this bulletin. If sanding had been practiced generally in Wisconsin, much of the crop that was destroyed by the frosts in September, 1909, through lack of water for reflowing, would have been saved. The estimated damage, as a result of the frosts of September 1 and 2, 1909, alone, to the entire Wisconsin crop was 50 per cent, while the loss at the Cranmoor Experi- ment'station was onlv 2 per cent. Moreover, only about 2.5 per cent of the crop was eventually saved because of the numerous severe frosts later in the month, to which reference has already been made. , rn The sanding is usually done during the winter, when the flood covers the marsh, ihe sand is spread over the ice" and it gradually smks to the surface of the bog in the spring as the ice melts." Cape Cod growers generally sand every few j-ears, adding a layer of about half an inch in thickness, but in Wisconsin no regular custom has been followed. While the greater portion of the Ap'pleton marsh at Mather had been sanded to a depth of about 2 inches in 1898, no further sanding was done until the winter of 1905-6, when a portion of the marsh previously sanded was covered with another layer. Weeding or cultivating has been practiced to a con- siderable extent, but the growth of vegetation is so rank in many of the bogs that much work is required in order to make any showing. The drainage is steadily being improved, the ditches have been placed closer together and are usually kept clean so as to assist in draming as well as in rapid reflowing. A study of ihe general and local conditions necessary for frost in the marshes.— The. natural conclusion from the data presented is that the study of local conditions in the marshes is of much importance. It is apparent that the temperature varies greatly in adjoining bogs and even in different portions of the same bog. During a frosty night damage may result in one portion of a bog and not in another, but serious frosts are usually general and not local. A grower may wish to conserve the water supply if the season is dry and the water low, because if he makes too liberal use of it, means for reflowing may not be at hand later when great danger threatens. In view of the fact that reflowing should not be resorted to any oftener than is absolutely necessary, the forecaster and the grower have between them a problem to solve that is sometimes very difficult. When low temperature threatens it must be first determined whether the night is to be clear, the barometer high, and the wind light. Of greatest nnpor- tance is the clearness of the atmosphere, as there will be no decided fall in temperature durmg any night unless the clouds clear away; even passing clouds over a marsh often raise the tem- perature several degrees. But local conditions seldom determine the condition of the sky. The reasons for cloudiness must be found in the movement of the areas of high and low pressure; and these reasons are not always apparent on the face of the weather map. The work of forecasting frost for the cranberry marshes is important and requires constant vigilance. True it is that damaging frosts seldom occur in midsummer. The frost of August 7-8, 1904, was abnormal— in fact, a phenomenal condition. The forecaster should know that such a low temperature is not likely to happen in every July or August, because it is far from being the fact, and it can only occur under circumstances on every side favoring its development. It is therefore a well-marked condition— one that would attract the attention of the forecaster almost instantly as he scans the weather map. Ordinarily, areas of high barometer do not bring frosts to the cranberry marshes of ^Yi.sconsin in the midsummer months, even though they are of considerable magnitude, have comparatively low temperature, an d move across the northern tier of states. <• In Massachusetts the sanding is now done mostly in the autumn, before the winter flow has been turned on. 118 The temperature of the soil is usually too high during the warm season to permit the formation of frost, and it is quite impossible for it to occur during these months followi^ a day of sunshine. On the other hand, frost occurs easih' in the moorlands on clear nights during the spring, early summer, and autumn when the soil is cold. As stated before, the conditions such as obtained during June 11, 12, and 13; 1906, would not be sufficient to cause frost later in the summer after the ground had become warm. In determining whether frost warnings should be issued, not only the weather maps must be studied carefully, but also the tempera- ture conditions in the bogs produced by recent hot or cold spells. The temperature of the soil is an important factor at any period of the growing season, and the reading of the maximimi thermometer is of mucli value, indicating, as it does, in a measure, the amount of heat conveyed to the soil during the daytime. Should the maximum temperature in the shelter he helow 70° on any day, and he followed at night hy clear sicy and light wind, harometer above normal and rising, there is strong prohahility that frost will follow in the hogs, especially if the pressure reaches a height of SO. 20 inches or more and the center of the HIGH passes over Wisconsin or the Lake Superior region . The theory that frost does not follow rain has no foundation. In fact, a day of light rain accompanied by a fresh wind which facilitates evaporation at the surface of the soil is often followed by a frosty night, as evidenced b\' numerous instances in 1907. (See Table 22.) Should it be expected that the minimum temperature at La Crosse or St. Paul will fall below 50°, ordinarily there is danger of damage in the cianberrv marshes on any clear night. Severe frosts have occurred in the bogs when the temperature at La Crosse was no lower than 48°, as on August 8, 1904, previously referred to. The temperature ''in the open" at the coldest place in the bog must fall below 29° in order that serious damage may occur. Probably a temperature for several hours "in the open" as low as 29° would be serious, but there are many instances of minimum temperatures of 29°, and even of 28°, when no frost or resulting damage was apparent. While frost may occur with a pressure not above normal during tlic spring, early summer, and autumn, this is not possible during the months of July, August, or early September. The barometer over the moorlands during the warm months must attain a height of at least .30.20 inches, so as to permit the cold air to gradually settle over the bog. On July 2, 1907, when the temperature fell to 29° at Mather with the pressure of 30.10 inches, no frost was observed, but it is probable that if the pressure were as high as 30.20 inches, a frost would have occurred. The higher the pressure the heavier the air, and the lighter the wind tlie more easily the cold air settles toward the groimd. As stated previously, it is important to determine from the weather map whether the weather will be clear over the moorlands because, regardless of how cold it is in tlie Northwest and how threatening tlie conditions, tliere can be no damage done during the growing season if the weather is cloudv at night; but severe frost mav occur earlv in ilav before the ^rro^^^n^ season, and in October after the berries have been picked, on cloudy and windy nights, but no damage can then result in the marshes. A perfect condition for frost in the moorlands exists when a liigh-pressure area from the Northwest moves eastward with the center over Lake Superior, sending cool north winds thence over Wisconsin, or when the HIGH settles directly over the moorlands, following a da}', or preferably two, of cloudiness, with some rain and wind, provided the clouds clear away and the wind subsides in the evening as the temperature begins to fall." ^Miile the study of local conditions is of value — temperature and its rate of fall, wind direction and velocity, humidity and pressure — these conditions may not. during inisettled conditions, assist materially in determining whether the weather will clear ami frost occur before the following morning. A strong, steady rise in pressure is the best local indication for clearing weather, and without this the weather \dll probably remain cloudy. AVliile a high jn-essure area moving eastward and southeastward over the Lake region is usually accompanied by clear, cool weather, occasionally the movements of such areas are abnormal and cloudiness persists in the front of the HIGH. A riMiiarkable instance of persistent cloudiness was noted from September o When a HIGH moves rapidly across Wisconsin, tlie barometer begins to fall and the wind lo rise immediately after the passage of the crest. Under .such conditions. :i falling temperature up to midnieht is followed by rising temperature during the balance of the night . I 119 2 to 5, 1905. On three successive days the pressure was high in the Northwest, reaching 30.44 inches at Prince Albert, and accompanied b}' freezing temperatures. This area moved slowh' southeastward, gradually losing force, but nevertheless maintaining low temperatures. On the morning of September 4 the pressure was highest over Manitoba, and frost was general throughout the Dakotas. The weather, however, although cold in the moorlands, never cleared during the entire period. Temperatures were as low as 37° on two successive nights, but by reason of the continued cloudiness frost did not occur in the bogs. A study of the local conditions, aside from the pressure, would not have enabled a person to determine whether it would clear on either of these nights. The cloudy weather covered a considerable area, in fact, several states, and the reason for this condition could not be found in the moorland sections of Wisconsin. Similar instances have been noted in other Septembers. Wlien cloudy weather prevails over a large area in front of a HIGH, it may ordinarily be expected to continue, unless there is a steady increase in pressure between the LOW and the HIGH. In case of doubt, special observations should be called for by the forecaster in the middle of the afternoon from the cranberry marshes and a few stations in the Northwest, with special reference to the maximum temperature in the bogs and the probability of clear weather for the ensuing night. It might be well to have an observation of soil temperature included in the reports from the cranberry marsh stations each morning in addition to the data usually telegraphed. The maps of August 7 and 8, 1904 (Figs. 4, 5), have been included in this bulletin, illus- trating a perfect contlition for the occurrence of frost. The cloudy weather during the 6th and 7th had prevented the usual warming of the soil, and the breezy weather of the 7th, through evapora- tion of the moisture near .the surface, evidently caused the soil to become colder. The maximum temperature in the shelter on August 6 was 76° at Mather and Cranmoor, and on August 7 it was 65° at Mather and 67° at Cranmoor. We have already showii what a great effect the temperature of the soil has upon the temperature of the air near the surface during any night, and that in marshes the places covered with dense vegetation, with thick matting of moss or thick growth of vines or ferns, are the ones of lowest temperature, especialh' if the soil has not been sanded and the drainage is poor. Wlien the soil is largely protected from the sun's heat by vegetation and the initial temperature at the surface is low in the evening, compara- tivel}' low minimum temperatures must result if the night be clear. The situation is even more pronounced if the previous day has been cloudy, because, as a consequence, the storing of heat in the soil has been interrupted and the point of critical temi)erature may therefore be reached more readily. Tlie relation between the temperxiture of the soil and the occurrence of frost is noticeahle in that it is practically impossible for frost to occur in the bogs on the first cool night following a warm spell, but it is lUtehj, if conditions are farorahle, on the second night after the soil has become cold. Growers claim, and with reason, that frost almost invariably occurs on the sec(jnd night of a oold spell, and even if it does occur on the first night the frost on the second night is likely to be more severe. Frost remains in the soil of an unflooded bog until cnmparatively late in the season, anfl there have been found instances of frost in the soil in nuxrshes as late as July 4. I'sually, however, when the winter flow is taken off in the spring the soil is free from frost. The temper- ature of the soil tends to gradually increase until after midsummer, and then gradually decrease again. The soil being cold in the spring and early summer, and again in the fall, frost is more likely to occur then, regardless of the accompanying conditions of atmospheric temperature and pressure. That is, the ground being cold, frost will occur in the marshes in May and early in June under the'injluence of areas of high pressure and accompanying low temperature that would be far from sufficient to cause frost during the midsummer months, when heat has been stored up in the soil. The length oftlte nights is also very important in estimating the probahiJity oftJie occurrence of frost, especially during the months of September and October, as the nights steadily grow longer and afford greater opportunity for radiation, without compensating insolation. The forecaster must have in mind the lowest temperature that may occur in the less- favored sections of the marsh, as it is evident that a wide range in temperature will be found in practically all marshes. Even with the knowledge that the lowest temperature "in the 120 open" will fall below the freezing point, it is not certain that there will be any damage. In fact, as has been stated before, the result of the investigation indicates that the temperature "in the open" must fall 2° to 4° below the freezing point in order to cause any serious damage, But the forecaster need not be the judge of what damage may ensue. It is for him to issue warnings, stating in his forecast the probabihty of light, heavy, or killing frost, and, if possible, how long the cool condition is hkely to last; because such information will often assist the cranberry grower in conserving his water supply. It is very important to know the hour in the evening that the frost is hkely to set in, because if it begins to form before midnight the damage to unprotected raarshes is certain to be serious, as the period of freezing in that event will continue through several hours till daybreak. When, however, the frost does not begin to form until nearly dawn there is little probabdity of damage. For traces of the curves at Berhn during the nights of September 13-14 and 27-28, 1906, see Figure 31, showing first in one instance a fall to freezing for only a brief period and in the other the temperature remaining at a low point for several hours. SEPTEMBER noon mat noon SEPTEMBER noon mat noon Fig. 31.— Berlin, Wis., ;906. Temperature curves in the vines on the marsh. Examples of two days — first, when minimum temperature touched freezing point for a few minutes — second, when the temperature remained at freezing for several hours. Irregularity of curves in both cases due to wind or passing clouds. There is an opportunity for tlie forecaster to give great assistance to the cranberry grower and to place in the hands of the latter all the information that may be available. If possible, it is advisable to send advice twenty-four hours or more in advance at times when the growers have the water supply low in the ditches, as is customary in the summer time, in order to enable them to raise the water, thus permitting easy flooding on the ensuing day. With this assistance the most improved marsh can then be flooded in a brief period. Man}' growers state that they want advice even wlien /ros< is possible, as well as prohahle, so that they may never be found entirely unprepared. If the water is allowed to get very low in the ditches, it may take twelve hours or more to flood, as the dry, spongy bog absorbs an immense amount of water. The grower, having been properly informed, can act accordingly, taking into consideration the probable conditions, the amount of Ins available water supply, and the possible damage, should he not reflow his marsh. When the water is warm during the summer season, and a light frost is expected, danger can usually l)e averted by raising the water no higher than the surface of 121 the marsh; yet such flooding affords but httle protection should a severe freeze occur. The grower is well acquainted Math the conditions of the vines and the fruit, and knows from experience when they are most liable to damage. He understands that at certain times during the season the marsh is practicall}^ immune to damage. For instance, after the winter flow is taken off in the spring and before the terminal buds have swollen and begun to burst there is little danger of damage, but later the liabihty is very great. The winter flow is held on some marshes later than others, but when it is dra^\^l off after May 15 the buds usualh^ begin to swell five to ten days later. After the upright starts out from the terminal bud it is very tender, and there is more danger to it than to the fruit bud, as it wiU freeze more easily. The fruit blossoms usually appear at Mather about June 10 and the vines are in full bloom about July 1. The setting of the fruit begins with the falling of the first blossoms and continues until the vines are out of blossom. The new terminal bud is generally formed by August 10, and often before that date. During 1906 there were many terminal buds fuUv formed by August 5. Until the terminal bud is well formed and protected a frost may destroy it, and thus ruin the prospects of a crop for the ensuing j^ear, aside from the damage to the crop of the current year. The terminal bud, however, is free from damage by frost usually after September 1. The fruit itself will freeze most easily just after setting, on account of the large amount of water it contains, and the riper the berry becomes the more hardy it is, so that when it is fully matured it can not he damaged except by a severe frost. Information of this character is of importance to the forecaster, simply because it indicates that the frost ■warnings have more value at one time of the year than another; that a frost in July or early in August, for instance, may wipe out not onh' the crop of the current year but even the prospects for a crop a year later. As an actual result of the freeze of August 8, 1904, the crop of that year in the Wisconsin River Valley was reduced about 40 per cent and that of 1905 about 25 per cent. It is possible for the forecaster to acquire a high degree of accuracy in special work of this character. He should never fail to issue warnings previous to serious frosts, and he seldom should make the mistake of issuing warnings for frosts that do not occur, but he should realize that it is his duty to save the crop. It is not enough for him to issue warnings in advance of ten frosts of wliich the growers take advantage in protecting their marshes, and j^et fail to send a warning in advance of the eleventh frost, which results in great injury. He should realize that he must carry oti this worTc to a successful conclusion from the beginning to the end of the season, or, in other words, that he must "save the crop." He may sometimes be excused for issuing warnings that are not verified, especially if there is ample water supply for protection ; but he %vill never be excused for failure to issue warnings in advance of serious damage. o LE N 'I W. B. No. 443. Issued Dec. 31, 1910. U. S. DEPARTMENT OF AGRICULTURE, WEATHER BUREAU. BULLETIN T. FROST AND TEMPERATURE CONDITIONS IN THE CRANBERRY MARSHES OF WISCONSIN. Prepared under the direction of WILLIS L. MOORE, Chief of Weather Bureau, By HENRY J. COX, Professor of Meteorology. WASHINGTON: GOVERNMENT PRINTING OFFICE. 1910. f ;■ ; -■■■ .it.-,:;: n: ■■^s../yy^;;m^ LIBRARY OF CONGRESS DDomiflEam ■^iSSil 1 I i v.- 1^ i P