CORNELL 
 
 UNIVERSITY 
 
 LIBRARY 
 
 ENGINEERING UBRAFTfi 
 
 Cornelt University Library 
 TN 948.M7G78 1919 
 
 The mineral industry of the British Empi 
 
 3 1924 004 703 728 
 
IMPERIAL MINERAL RESOURCES 
 BUREAU. 
 
 THK MINKHAL LNDUSTRV OF 
 THE BRITISH KMPIHE 
 
 AMi 
 
 F()in:iG\ COINIKIKS. 
 
 WAR PERIOD. 
 
 M O N A Z I 'I' E . 
 
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 192a 
 
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The original of tiiis book is in 
 tine Cornell University Library. 
 
 There are no known copyright restrictions in 
 the United States on the use of the text. 
 
 http://www.archive.org/details/cu31924004703728 
 
IMPERIAL MINERAL RESOURCES 
 BUREAU. 
 
 THE MINERAL INDUSTRY OF 
 THE BRITISH EMPIRE 
 
 AND 
 
 FOREIGN COUNTRIES. 
 
 WAR PERIOD. 
 
 MONAZITE. 
 
 (1918-1919.) 
 
 LONDON ; 
 PRINTED AND PUBLISHED BY 
 
 HIS MAJESTY'S STATIONERY OFFICE. 
 To be purchased throuffh any Bookseller or directly from 
 H.M. STATIONKEY OFFICE at the following addrc-^e.: 
 Imperial House, Kinqswat, Lgndon, W.c.2, and 
 28, abingdon street, london, s.wa ; 
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 1, st. andrew s crescent, cardiff : 
 23, Forth street, Edlnbcrgh : 
 or iroto E. PONSONBV, LTD., 116. Grafton Street, DnBum. 
 
 1920. 
 Price 6d Net. 
 
£^A e^iT, jrmioet^^riL TJ^s-rinrre ^ loaJ2)o^ , 
 
 77V 
 Ml 
 
 
PREFACE 
 
 The following digest .of statistical and technical information 
 relative to the production and consumption of monazite will 
 constitute a part of the Annual Volume on the Mineral Resources 
 of the British Empire and Foreign Countries. 
 
 In this, the first year of publication, an effort has been made 
 to fill in, as far as possible, the hiatus due to the war in the 
 publications relating to mining and metallurgical statistics. 
 Labour, health and safetj' statistics have been omitted owing to 
 the difficulty involved in procuring reliable information for the 
 war period, but in future issues these statistics will be included 
 in respect of each year. 
 
 Resort will also be had, to a much greater extent than at 
 present, to graphical lepresentation of statistics of production, 
 consumption, costs and prices 
 
 R. A. S. REDMAYNE, 
 
 Chairman of the Governors. 
 
 '2, Queen Anne's Gate Buildings, 
 London, S.W. 1. 
 June, 1920. 
 
 (2!l64U Wt. 5715-.S8/701 100 1 8/20 H.St. Q. ■> 
 
CONTENTS. 
 
 PAGE. 
 
 GENERAL 5 
 
 WORLD'S PRODUCTION 6 
 
 BRITISH EMPIRE— 
 
 United Kingdom 7 
 
 India ... ... ... ... ... ... ... ... ... 8 
 
 Ceylon 9 
 
 FOREIGN COUNTRIES— 
 
 Brazil 9 
 
 United States of America , ... 10 
 
 REFERENCES TO TECHNICAL LITERATURE 12 
 
 APPENDIX— 
 
 Note on mesothorium in monazite by Professor Soddy, F.R.S. 15 
 
GENERAL. 
 
 Monazite is essentially a phosphate of the cerium earths, but 
 its commercial value is due chiefly to the presence of a variable 
 amount of thoria, the oxide of thorium. This is extracted from 
 it by chemical treatment and marketed in the form of thorium 
 nitrate for use in the manufacture of gas mantles. The mineral 
 is found in the form of grains, usually of a honey-yellow colour, 
 in beach and river sands. Commercial suppUes of the sand were 
 first obtained from the beach sands of the Brazihan coast ; but 
 deposits of a closely similar character were found some years ago 
 on the coast of Travancore in Southern India, and they have 
 smce been found in Ceylon. 
 
 Monazite sand can be easily identified as a rule by its colour, 
 the well-rounded form nl the griiins, its high specific gravity 
 (about 5'2), and weakly magnetic character. In consequence 
 of this magnetic character it can usually be isolated from th<^ 
 other heavy minerals by means of an electromagnet. Monazit.' 
 shows a characteiLstic absorption spectrum, but is best identified 
 by the physical characters already enumerated, and by the fact 
 that it yields a phosphate leaction 
 
 The amount of thoria in monazite varies. Concentrates should 
 contain not less than four or five per cent, of thoria, and much 
 sand exported from Brazil has not contained more than this 
 amount. The best Brazilian concentrates contain about 
 6 per cent, of thoria, whilst those of Travancore and Ceylon 
 contain about 9 per cent. 
 
 In some localities monazite sand has been found in a condition 
 sufficiently concentrated by wave and tidal action to make its 
 shipment economically possible in the natural state. Usually, 
 however, the sand contains a large admixture of other minerals 
 and requires to be concentrated by hydraulic and electromagnetic 
 or other methods before it can be marketed. 
 
 G-ermany had formerly a monopoly of the manufacture of 
 thorium nitrate, but for some time previous to the outbreak of 
 the recent war France and the United States had been manu- 
 facturing this product, chiefly from Brazihan and Indian 
 monazite. As a result of the war. and the serious shortage of 
 thorium nitrate caused by the cessation of German supplies, other 
 countries have taken up the manufacture of the nitrate, and the 
 United States appears to have been especially successful in in- 
 creasing its production. British manufacturers have not until 
 .recently succeeded so well. 
 
 Monazite is mainly employed for the production of thorium 
 nitrate, which yields thoria on ignition. The mixture of oxides 
 in gas mantles is derived from a mixture containing about 99 per 
 cent, of thorium nitrate and 1 per cent of cerium nitrate. 
 Jjarfje residues of cerium compouniis are obtained as by-products. 
 
These were formerly almost useless, but they now supply the 
 cerium required for the manufacture of the alloy ferro-cerium, 
 which typically contains about 30 per cent, of iron, and which is 
 used in the manufacture of sparking de\dces. Air friction causes 
 ferro-cerium to ignite when it is attached to a moving projectile, 
 and for that reason it hajS been used to illuminate the path of a 
 shell. Among other uses of cerium compounds, mention may 
 be made of their use for illuminating purposes in naval search- 
 lights, their application in the manufacture of certain electrodes, 
 and also of their use in medicine to a small extent. A special 
 variety of optical glass containing cerium is made into spectacles 
 for use by glass-furnace operators to avoid injury to their eyes. 
 
 The amount of uranium and therefore of radium in monazite 
 is as a rule very small, though exceptionally it may amount to 
 3 or 4 per cent, of uranium oxide, as in some specimens of vein 
 monazite from Travancore. 
 
 Monazite is the chief source of mesothorium, which closely 
 resembles radium in its properties, and is obtained from the 
 monazite as a by-product in making thorium nitrate. The 
 amount present is only a few milligrams per ton of the monazite, 
 and would be too small to make it worth while to work the 
 monazite for the mesothorium alone. The mesothorium is sold 
 on the basis of its radio-activity compared with radium bromide, 
 and is at present (June, 1920) worth from £6 to £8 per 
 milligram. 
 
 The pre-war price of monazite sand was not less than ±'5 per 
 unit of thoria per ton, and that of thorium nitrate 23s. per kilo. 
 The present price of monazite is £i 12s. 6d. per unit of thoria 
 per ton at the mine in Travancore. The c.i.f . value at European 
 ports (June, 1920) is about £6 10s. per unit. Thorium nitrate 
 is at present worth 38s. pei" kilo. 
 
 The British requirements of thorium nitrate for home con- 
 sumption amount to between 75,000 and 100,000 kilos. 
 
 WORLD'S PEODUCTION OF MONAZITE. 
 
 At the outset of the period under review, the world's production 
 of monazite was limited to Brazil and India, the production in 
 Brazil in 1912 being about three times the tonnage and nearly three 
 times the value of that in India. Since 1913, however, India has 
 been the leading producer. The actual disparity in thoria pro- 
 duction betweeen India and Brazil is much more pronounced than 
 that between the monazite production figures since 1914, as given 
 below, owing to the fact that the Travancore monazite is much 
 richer in thoria than the Brazilian. The amount produced in the 
 United States was neghgibly small and there was no production 
 in that country in 1918. Ceylon produced monazite concentrates 
 in commercial quantities for the first time in 1918. 
 
The figiiros for the output of monazite in long tons in the 
 various producing ronntries from 1913-1919 are as follows : — 
 Production of Monazite. 
 Long tons (2240 lb.) 
 
 1913. 
 
 1914. 
 
 1915. 
 
 1916. 
 
 1917. 
 
 1918. 
 
 191'.'. 
 
 India... 
 
 Ceylon 
 
 Brazil 
 
 United States 
 
 1,235 
 
 1,186 
 
 1,108 
 
 1,292 
 
 1,940 
 
 2,117 
 
 20 
 
 491 
 
 1,415 
 
 590 
 
 433 
 
 
 
 1,118 
 
 ~ 
 
 
 16 
 
 17 
 
 (a) 
 
 
 
 2,000* 
 
 (a) Not reported by the United States Geologie;il Survey, but stated by The 
 Mineral Industry for 1018 to have been 34-7 tons. 
 • Estimated. 
 
 United Kingdom. 
 
 The outbreak of the war resulted in a serious shortage of 
 thorium nitrate in the United Kingdom, us supplies up to that 
 time had been obtained from abroad. The pritr of the nitrate is 
 
 reported to have risen from 10 shillings to 90 shil 
 
 mgs a 
 
 kilogram 
 
 towards the end of 1914, and elTorts were made liv British 
 manufacturers to obtain adeipiate supplies. In the manufacture of 
 thorium nitrate from monazite, hi)\\cver, only a small nu asure of 
 success had been attained until reciMilly. and considerable 
 amounts of the nitrate hav(^ been imported from the T'nited 
 States for the use of British firms engaged in the manufacture of 
 gas mantles. For the last year or two, however, it has not been 
 necessary to import thorium nitrate into the United Kingdom. 
 
 Value of Imports of Moiinzitr Sand iiilo iJic United Kingdom. 
 (Annual Statement of the Trade of the United Kingdom.) 
 
 Value of imports... 
 
 1914. 
 
 i: 
 
 22,r45 
 
 r.ii5. 
 
 
 I'.IKl. 
 
 t: 
 
 8.224 
 
 i'.m; 
 
 14,773 
 
 I'.il^ 
 
 £ 
 
 8,iji;8 
 
 11119. 
 
 £ 
 
 9,3tl. 
 
 Value of Imports and E.cporls of Can Mantles to and from th( 
 United Kingdom. 
 
 (Annual Statement of the Trade of the United Kingdom.) 
 
 Exports. 
 
 Year. Imports. 
 
 £ 
 
 1913 302,576 
 
 1914 199,299 
 
 1915 2;i().ti7o 
 
 1916 ^7,067 
 
 1917 24.106 
 
 1918 26,S1,5 
 
 1919 31.771 
 
 Domestic 
 
 Foreign 
 
 produce. 
 
 produce. 
 
 £ 
 
 f 
 
 32,566 
 
 .3,650 
 
 47,400 
 
 4.359 
 
 93,960 
 
 4.>48 
 
 144,292 
 
 7,491 
 
 94,058 
 
 — 
 
 103,297 
 
 — 
 
 SS,893 
 
 — 
 
lUDlA. 
 
 In 1911 and 1912, monazite assumed for the first time an im- 
 portant place in the mineral production of India, and in the latter 
 jear was placed by the Greological Survey among minerals for 
 which trustworthy returns were available. Previous to the war 
 the mineral was exported to Germany. The output, which was 
 obtained from beach sands between Muttum and Colachel, on the 
 Travancore coast, was in the hands of a firm which operated 
 under German control. After the outbreak of the war these enemy 
 interests were soon ehminated, and the industry was placed on a 
 satisfactory basis under the control of British capital. The 
 Travancore deposits are extensive, and will suffice to meet the 
 world's requirements for many years. 
 
 The percentage of monazite in Travancore beach sands is 
 variable, being low in the dune sands, and higher on certain parts 
 of the beach where it has been concentrated by wave-action. 
 The chief minerals found with monazite in the concentrates are 
 ilmenite and zircon, both of which can be effectively separated 
 from the monazite as by-products by electro-magnetic treatment, ' 
 and may prove ultimately to be of economic value. 
 
 Although the total production of monazite from 1911 to 1918 
 inclusive amounted to 10,845 tons, valued at £335,146, the exports 
 from Travancore for the same period, foreign and coastwise, are 
 stated to have been only 7,706 tons, of an approximate value of 
 £220,000. The exports from the British Indian port of Tuticorin 
 amounted to 604 tons, valued at £27,000, and 882 tons, valued at 
 £40,000, in 1917-18 and 1918-19 respectively, were probably for 
 the most part of Travancore monazite. The exports went chiefly 
 to the United States and the United Kingdom, but small quan- 
 tities were sent to Japan. 
 
 Owing to lack of shipping facilities in Travancore the monazite 
 is not at present shipped direct, but is transported to Tuticorin in 
 small coasting vessels, except during the monsoon, when it is 
 carried overland. It is exported from Tuticorin in bags of 1 cwt. 
 each. 
 
 The tonnages and values of the monazite production in India 
 during the period 1913-1919 have been as follows : — 
 
 Production of Monazite in India 
 
 * 
 
 
 Quantity 
 
 Value 
 
 Year. 
 
 long tons. 
 
 £ 
 
 1913 
 
 1,235 
 
 42,012 
 
 1914 ... 
 
 1,186 
 
 41,411 
 
 1915 
 
 1,108 
 
 38,238 
 
 1916 
 
 1,292 
 
 37,714 
 
 1917 
 
 1,940 
 
 56,489 
 
 1918 
 
 2,117 
 
 58,819 
 
 1919 
 
 '2,000 (estunated.) 
 
 * Rec. Geol. Surv. India. 
 
Ceylon.* 
 
 In recent years substantial deposits of monazite sand have 
 been found near Bentota and also near Kudremalai on the west 
 coast of Ceylon by the Ceylon Government Mineral Survey. 
 Samples of the Bentota sand contained as much as 47 per cent, 
 of monazite and over 4 per cent, of thoria ; by concentrating these 
 electromagnetically to eliminate the ilmenite and zircon, a very 
 high-grade concentrate of monazite was obtained containing 
 nearly 10 per cent, of thoria. The monazite sand near Bentota 
 is easily concentrated by means of the electromagnet, and 
 yields an exceptionally high-grade product. 
 
 The Ceylon Government recently obtained a magnetic 
 separator for the purpose of concentrating the sand. The 
 machine was put into operation in 1918 near Bentota, and the 
 output of concentrates during the year amounted to 20 tons. 
 
 In addition to monazite, some thorianite has been produced in 
 Ceylon during the period under reNiew, but only small parcels 
 have been sold. Thorianite ;ind thorite are scarce, compared with 
 monazite, even in Ceylon, and Ceylon's future contribution to 
 thoria production is likely to l)e in the form of monazite, rather 
 than thorianite and thorite. 
 
 Brazil. 
 
 The monazite exported from Brazil has been obtained chiefly 
 from beacli sands of Espirito Santo and Bahia. The world's 
 supply of monazite was formerly obtained wholly from these 
 deposits the sands of which were rich enough to be shipped in 
 their natural condition. In recent years it has been necessary 
 to concentrate them by hydraulic and electromagnetic methods. 
 Good Brazilian concentrates contain on the average only about 
 6 per cent of thoria. 
 
 Deposits of sand and gi-avel along streams and ri\'ers of the 
 interior of Brazil frequently contain monazite, but only in com- 
 paratively small amounts, one or two per cent, iii some cases. 
 As a rule, however, they are no richer than the sands and gravels 
 of the Carolinas in the United States, and they are too poor in 
 monazite to make exploitation profitable so long as richer beach 
 deposits are available. 
 
 The destinations of the exports of monazite from Brazilt 
 during the period under review are as follows (in metric tons) : — 
 
 Destination. 
 
 ( 1913. 
 
 1914. 
 
 1915. 
 
 1916. ! 1917. 
 
 191«. 
 
 1919. 
 
 United Kingdom 
 
 France 
 
 Germany 
 
 United States 
 
 3 
 778 
 256 
 400 
 
 1437 
 
 600 
 
 439 
 
 — 
 
 1,136 
 
 499 
 
 
 Totals 
 
 600 
 
 439 
 
 — 
 
 1,136 
 
 499 
 
 
 • Colonial Reports— Annual, No. 1007, Ceylon for 1918. 
 t Brazil ; The Pan-American Union, 191H. ,sVf nho the United States 
 imports on p. 10. 
 
10 
 
 United States.* 
 
 The output of monazite in the United States during the period 
 under review has been almost neghgibly smah. The gravel 
 deposits in the Garohnas from which the United States production 
 has been chiefly obtained are patchy in distribution and poor in 
 quahty. According to the Bureau of Mines (Monazite, thorium 
 and mesothorium ; K. L. Kithil, Technical Paper 110, 1915) 
 the percentage of monazite in the gravel averages only 0'25 per 
 cent., which means that even assuming a 100 per cent, recovery, 
 400 tons of gravel have to be treated to obtain 1 ton of monazite. 
 There is, moreover, a comparatively large overburden, amounting 
 to more than twice the amount of the monazite gravel worked. 
 With wages at $1 to $1'25 a day in 1915, it was estimated that 
 the cost of production of machine-separated monazite concentrate 
 containing 92-95 per cent, of the mineral and about 4 J per cent. 
 of thoria was $169 per ton at the place of concentration. To 
 this had to be added the cost of management, commission, tolls 
 if any, loading on cars and freight to chemical plant or port. 
 
 It is therefore hardly surprising that these Carohna deposits 
 cannot compete with imports of monazite drawn from the richer 
 deposits of India and Brazil. It has been estimated that the 
 Carohna deposits contain from 15,000 to 20,000 tons of monazite 
 concentrate containing about 4-J- per cent, of thoria. Efforts have 
 been made to concentrate the monazite from the crushed rock 
 (gneiss) in Carolina, but even with the richest rock, containing 
 up to 0'2 per cent, of monazite, it has been found that the costs 
 of production from this source are too high . 
 
 Other deposits of gravel containing monazite associated with 
 gold have been found in Idaho and Colorado, but so far these have 
 not yielded any considerable supply; and it is pointed out that, 
 although the Idaho gravels appear to be more extensive than 
 those of the Carolinas, the wages there are much higher. 
 
 In 1917, it was reported that monazite sand had been raised 
 by a suction dredge on the sea shore near Jacksonville, Florida. 
 The concentrates obtained by tabling the sand contained ilmenite, 
 rutile and zircon and the monazite was separated from this by 
 electromagnetic treatment. The fact that there was no output 
 of monazite in the U.S.A. during 1918 indicates that production 
 from this deposit had not proved successful. 
 
 Unless, therefore, some new deposit of monazite is discovered, 
 more promising in quality than those hitherto found, it appears 
 that the United States will continue to depend on imports of 
 monazite or thorium nitrate. In this connection it is noteworthy 
 that, as already indicated, the United States has made great 
 
 * Ann. Reps. Min. Res., U.S.A. 
 Tech. Paper No. 110, U.S.A. Bur. of Mines, 1915. 
 Foreign Comm. and Navig., U.S.A. 
 
il 
 
 progress in the manufacture of thorium nitrate in the period under 
 review. This fact is well illustrated by the figures for imports 
 and exports ;^ivfn below. 
 
 It will be .seen from the table showing imports of monazite that 
 the United States imported 49'-i tons of monazite, all from 
 Brazil, in the fiscal year ending 30th June, 1913. In 1915, im- 
 port;iti(Mi of Indian monazite was commenced, and in the fiscal 
 year 30th June, 1918, the impo'ts from Brazil still figured at 
 about 500 tons, whilst the impoits from British sources amounted 
 to about 1,720 tons. 
 
 Imports of Monazite to the United States for Fiscal Years 
 ending June 30. 
 
 
 
 
 Quantity (long tons). 
 
 1918. 
 
 
 
 1913. 
 
 1914. 
 
 1915. 
 
 1916. 1 1917. 
 
 1 
 
 1919. 
 
 British 
 
 Empire. 
 Brazil 
 
 493 
 
 492 
 
 131 
 654 
 
 523 
 1.58 
 
 507 
 482 
 
 1,721 j 
 501 
 
 Total ... 
 
 493 
 
 492 
 
 7H.-, 
 1 
 
 681 
 i/^alue (.•?) 
 
 989 
 
 2 222 
 .19 IH. 
 
 
 
 1913. 
 
 1914. 
 
 1915. 
 
 1916. 
 
 1917. 
 
 191;. 
 
 British 
 
 Empire. 
 Brazil 
 
 K4,779 
 
 ri'2,.s-i'.) 
 
 30,11)-, 
 69,22 1 
 
 113,537 
 16,757 
 
 114,940 
 54,519 
 
 284,749 
 44,962 
 
 
 Total ... 
 
 H4,77'.t 
 
 52,329 
 
 99,325 1 1.30,294 
 
 169,4,59 
 
 329,711 
 
 
 Valuf of Imports of Mantles for Gas Burners to the United States 
 for Fiscal Ytar.s ending June 30. 
 
 Year. 
 
 United 
 Kingdom. 
 
 Canada. 
 
 Other 
 Countries. 
 
 
 .'^ 
 
 ,*s 
 
 ,, 
 
 1913 
 
 5,627 
 
 453 
 
 66,186 
 
 1914 
 
 
 
 42,042 
 
 318 
 
 38,082 
 
 1915 
 
 
 
 13,,5.38 
 
 256 
 
 27.767 
 
 1916 
 
 
 
 449 
 
 263 
 
 5.942 
 
 1917 
 
 
 
 — 
 
 28 
 
 449 
 
 1918 
 
 
 
 4 
 
 33 
 
 822 
 
 1919 
 
 
 
 
 
 
12 
 
 Monazite Sand Produced in the United States and Monazite Sand 
 and Thorium Nitrate Imported for Consumption. 
 
 Tear. 
 
 Monazite Sand 
 produced in the 
 United States. 
 
 Imports 
 
 of Monazite 
 
 Sand. 
 
 Imports 
 
 of Thorium 
 
 Nitrate. 
 
 Price 
 poiind 
 
 Quantity 
 (long 
 tons). 
 
 Value 
 ($). 
 
 Quantity 
 (long 
 tons). 
 
 Value 
 ($)■ 
 
 Quantity 
 (long 
 tons). 
 
 Value 
 
 ($). 
 
 Thorium 
 
 Nitrate 
 
 ($). 
 
 1913 ... 
 
 1914 ... 
 
 1915 ... 
 
 1916 ... 
 
 1917 ... 
 
 1918 ... 
 
 1919 ... 
 
 16 
 17 
 
 3,600 
 3,400 
 
 » 
 
 365 
 
 344 
 
 837 
 
 1,088 
 
 2,602 
 
 1,337 
 
 65,848 
 61,595 
 161,456 
 188,383 
 355,017 
 204,661 
 
 53 
 
 46 
 
 30 
 
 0-4 
 
 0-5 
 
 230,628 
 
 239,376 
 
 170,268 
 
 3,884 
 
 2,359 
 
 2-73 
 2-98 
 4-51t 
 6-25$ 
 
 • One producer only 
 from $3-75 to $6-00. 
 
 figures not published. f The prices ranged 
 
 ' J The prices ranged from $4 • 75 to $8 • 50. 
 
 Exports of Gas Mantles (U.S.A. Produce) from the United 
 States, during the Year ended SOth June, 1918. 
 
 United Kingdom ... 
 
 .. $ 1,187 
 
 British Africa 
 
 5,035 
 
 Canada 
 
 86,309 
 
 British India 
 
 27,755 
 
 Straits Settlements 
 
 1,201 
 
 Hong^ Kong 
 
 7,047 
 
 Australia 
 
 13,609 
 
 New Zealand 
 
 2,932 
 
 Other British Possessions 
 
 1,334 
 
 South America 
 
 70,182 
 
 Other Foreign Countries 
 
 19,628 
 
 Total 
 
 .. $236,219 
 
 
 
 REFERENCES TO TECHNICAL LITERATURE. 
 
 The mineral production of India (annual), by H. H. Hayden; Rec. Geol. 
 
 Surv. of India. 
 Monazite Sand. The Mineral Industry (annual), edited by G. A. Rousli. 
 Mineral Resources of the United States (annual), U.S. Geol. Surv. 
 
 1913. 
 
 Die Verwendung der seltenen Erden, yon C. R. Bohm; Leipzig, Veit & 
 
 Co., 1913. Rev. in Journ. Soc. Chem. Ind., 1913, 32, 1089. 
 Tungsten-thorium, a ductile alloy, by L. V. Grotthus; Metall u. Erz, 
 
 1913, 10, 844. Abstr. in Journ. Soc. Cjhem. Ind., 1914, 33, 262-263! 
 Cerium alloys with silicon and bismuth, by R. Vogel; Elektrocheirn. 
 
 Zeits., 1913, 20, 53. Abstr. in Journ. Inst. Met., 1914, 11, 298, and 
 
 Journ. Soc. Chem. Ind., 1914, 33, 85. 
 
13 
 
 1914. 
 
 R«port on the results of the mineral survey of Ceylon ; Colonial Reports, 
 
 Misc., No. 87, 1914, pp. 1-22, Cd. 7176. 
 Concentration of monazite and wolframite, by F. Freise; Metall u. 
 
 Erz, 1914, 11, 573-578, 567-594. Abstr. in Journ. Soc. Chem. Ind., 
 
 1915, 34, 497. 
 Monazites from some new localities, by S. J. Johnstone; Journ. Soc. 
 
 Chem. Ind., 1914, 33, 55-59. 
 Preparation of cerium and its alloys, by M. Moldenhauer ; Chemiker- 
 
 Zeitg., 1914, 38, 147. Abstr. in Journ. Soc. Chem. Ind., 1914, 
 
 33, 203. 
 Monazite sands of Travancore, by G. H. Tipper; Rec. Geol. Surv. India, 
 
 1914. 44. 186-192. 
 
 1915. 
 
 Monazite in Brazil, by A. L. M. Gottschalk; U.S. Comm. Rep., 1915. 
 
 March 16, Abstr. in Min. Eng. World, 1915, 42, 903-904. 
 Cerium alloys, by F. Henaman, Internat. Journ. Motallography, 1915, 
 
 7, 174. Abstr. in Journ. Inst. Met., 1915, 14, 232. 
 Monazite, thorium and mesothorium, by K. L. Kithil. U.S. Bur. Mines, 
 
 Tech. Paper No. 110, 1915, 32 pp. 
 The rare earths, their occurrence, chemistry and technology, by K. L 
 
 Levy; London, E. Arnold, 1915. 
 Report on Brazil monazite, E. V. Morgan; U.S. Comm. Rep., 1915, 
 
 February 3rd. 
 Oerium-magnesium alloys, by R. Vogel; Zeits. f. anorgan. Chemie, 1915, 
 
 91, 277. Abstr. in Journ. Inst. Met., 1915, 13, 326. 
 
 1916. 
 
 The progress of the British rare earth industry during the War by S. J. 
 
 Johnstone; Journ. Soc. Chem. Ind., 1916, 35, 811-813, 1040. 
 Zircon, monazite, and other minerals used in the production of chomical 
 
 compounds employed in the manufacture of lighting apparat\is, 
 
 by J. H. Pratt; N. Carolina Geol. and Econ. Survey Bull. 25, 
 
 1916. 
 Thorium minerals, by W. T. Schaller ; U.S. Geol. Suiv. Mm. Res., 1916, 2, 
 
 223-237. 
 Mineral resources of Mysore, by W. F. Smeeth and P. S. Iyengar, 
 
 Mysore Dept. Mines and Geol. Bull. 7, 1916, pp. 191-192. 
 Recent work on monazite and other thorium minerals in Ceylon; Bull. 
 
 Imp. Inst., 1916, 14, 321-369. Abstr. Journ. Soo. Chem. Ind., 1917, 
 
 36, 88. 
 
 1917. 
 
 Monazite in Morgui and Tavoy, by A. M. Heron; Rec. Geol. Surv. India, 
 
 1917, 48, 179-180. 
 A Florida rare-mineral deposit, by D. M. Liddell; Eng. Min. Journ. 
 
 1917, July 28. 
 Production of cerium by electrolysis, by M. de K. Thompson; Met. and 
 
 Chem., Eng., 1917, 17, 213-215. Abstr. in Journ. Soc. Chem. Ind., 
 
 1917, 36, 1099, and Journ. Inst. Met., 1918, 19, 288-289. 
 Cerium-iron alloys, by R. Vogel; Zeits. f. anorgan., Chemie, 1917, 99, 25. 
 
 Abstr. in Journ. Soc. Chem. Ind., 1917, 36, 885, and Journ. Inst. 
 
 Met., 1917, 17, 334-335. 
 
 1918. 
 
 Monazite, by S. J. Johnstone; Journ. Soc. Chem. Ind., 1918, 37, R 
 
 373-376. 
 Ratio of mesothorium to thorium, by H. N. McCoy and L. M. Henderson; 
 
 Journ. Amer. Chem. Soc, 1918, 40, 1316-1326. Abstr. Journ. Soc. 
 
 Chem. Jnd., 1918, 37, 732a. 
 
14 
 
 1919. 
 
 On pitchblende, monazite and other minerals from Pichhli, Gaya district, 
 
 Bihar and Orissa, by G. H. Tipper: Reo. Geol. Surv. Ind., 1919, 
 
 50, 255-262. 
 The base metal resources of the Union of South Africa, by W. Versfeld; 
 
 Pretoria, Dept. Mitaes and Industries, 1919 (cerium and thorium 
 
 103-105). 
 The manufacture of ferrocerium sticks for pyrophoric use (Camillo's 
 
 patent). Met. Ind., 1919, 15, 84. 
 
 1920. 
 
 New ferro-alloy (ferrocerium) for deoxidizing molten iVon; Iron Age, 
 1920, 105, 324. 
 
15 
 
 APPENDIX. 
 
 NOTE ON MESOTHORIUM IN MONAZITE 
 
 By Professor Soddy, F.R.S. 
 
 The milli'gram of mesothorium is defined as the quantity (actually 
 unweighable) of mesothori'um 1 and 2 in equilibrium which has the sam^^ 
 y -ray activity as 1 milligram of radium, in equilibrium with its first four 
 products, when measured through 3mm. of lead. 
 
 The " milligram of mesothorium " is in equilibrium with 19 kilograms of 
 thorium element, hence, per ton (1000 kilograms) of thorium in tho 
 mineral, there are 52-6 " mg. of mesothorium." In commercial meso- 
 thorium preparations, derived presumably from Brazilian monazite, there 
 are, of 4 parts of total y -activity, 3 parts due to mesothorium and 1 due 
 to the isotopic radium. 
 
 Hence per ton of thorium in such minerals there exists mosothorium- 
 radium equal to about 70 milligrams of radi'um, or 131 milligrams of 
 hydrated radium bromide (RaBr^. 211^0) the commercial standard to which 
 it is usually sold. 
 
 The quantity for any other monazite can be calculated from the per- 
 centage of contained thorium and uranium, each 19 kilograms of thorium 
 element and each 3 kilograms of uranium element contributing 1 mg. 
 of " mesothorium," equivalent to 1"87 mg. of RaBr, .211^0 in y -activity. 
 
 These figures are considerably higher than that — 2'5 mg. per ton of 5 
 per cent. ThO, mineral — referred to in the Report and probably loss has. 
 occurred in extraction. The ratios given were worked out for the most 
 part bv H. N. McCoy and L. M. Henderson (J. Amer. Chem. Soc., 1918, 
 40, 1316).