April 4, 1901] 



NATURE 



551 



may be- and however great its concentrating power may be. 

 We have seen that when exposed cold as soon as possible after 

 the total phase of the eclipse, it was twenty-seven minutes after 

 totality before the water boiled. One-third of the sun was then 

 uncovered. It is, therefore, reasonable to suppose that, if the 

 eclipse had happened at noon, so that the first half of it could 

 have been utilised as well as the second half, the sun would 

 have kept steam in the calorimeter, and it would have con- 

 tinued to distil until two-thirds of the sun's surface had been 

 obscured. Then distillation, if it did not cease, would become 

 so slow that its rate would have no value, and fifty-four minutes 

 would elapse before one-third of the sun would again be un- 

 covered, during which the calorimeter would get cold. During 

 this interval steam must be kept artificially. This is very easy. 

 The glass tube which forms the steam dome is attached to a 

 metal collar which screws down on a washer. It can, therefore, 

 be easily detached. If, then, the steam tube of the calorimeter' 

 be connected by means of an india-rubber tube with a flask in 

 which water is kept boiling, steam can be passed through the 

 calorimeter at the normal rate until it is judged suitable to expose 

 it again to the sun. There is no difficulty about this. 



Although quite insignificant as a natural phenomenon, an 

 annular eclipse is better for calorimetric experiments than a 

 total one. On November ii, 1901, there will be an annular 

 eclipse visible in Ceylon. The annular phase will last over ten 

 minutes, and, at its greatest, 0-875 of the sun's disc will be 

 covered. It is fairly certain that the calorimeter used in 1882 

 would not keep steam through this phase, but a larger reflector 

 might be used. It would be worth while to have a reflector of 

 such a size that steam would certainly be kept through the 

 whole eclipse, especially during the annular phase, when all the 

 radiation is from the peripheral region. J. Y. Buchanan. 



THE MINING STATISTICS OF THE WORLD. 



T T is impossible to imagine a more concise, more intelligible, 

 •*■ or more inexpensive collection of comparative mineral 

 statistics than is contained in the General Report on Mines and 

 Quarries prepared by Dr. C. Le Neve Foster for the Home 

 Office, and it would be difficult to find an editor possessing in 

 a more marked degree the requisite technical knowledge, 

 literary skill and critical acumen for the difficult task of 

 abstracting and collating the heterogeneous official mineral 

 statistics of foreign countries and of rendering them intelligible 

 to the general reader. In many countries the statistics published 

 are imperfect or antiquated. Nevertheless, as regards output, 

 Dr. Le Neve Foster has succeeded in getting together a mass of 

 figures which, in the case of the more important minerals, may 

 certainly be regarded as trustworthy. He has brought into one 

 focus a representation of the present position of the mining 

 industries of the world, and has thus rendered it possible to 

 comprehend the enormous development that has taken place 

 within recent years. The statistics given are of the greatest 

 importance from a commercial point of view. In the United 

 Kingdom alone the value of the minerals raised in 1899 was 

 97,470,000/., and the vast sums representing British capital 

 invested in mines in all parts of the world will be readily appre- 

 ciated. Some indication of the remarkable strides made by 

 the mining industry during the past ten years is afforded by the 

 following comparison of the world's output of metals in 1889 

 and in 1899 : — 



In 1899 the world produced 723,239,000 tons of coal, 

 16,755,000 tons of petroleum, and 12,890,000 tons of salt. 

 Nearly one-third of the coal supply was furnished by the 

 British Empire. The United States supplied nearly another 

 third, and Germany more than a sixth. The remainder was 

 contributed mainly by Austria- Hungary, France and Belgium. 

 The coal production of the principal countries was as follows : — 



NO. 1640, VOL. 63] 



United States 



United Kingdom 



German Empire . 



Austria-Hungary , 



France 



Belgium 



Japan 



India 



New South Wales 



Canada 



Spain 



Transvaal ... 



Metric tons. 



... 230,254,000 



... 223,627,000 



... 135,824,000 



... 37,562,000 



... 31,218,000 



... 22,072,000 



6,761,000 



5,016,000 



4,671,000 



4,142,000 



2,671,000 



1,938,000 



In 1889 the United States for the first time outstripped 

 Great Britain as a coal-producing country. In twelve months 

 the British increase was 18,000,000 tons, but that of the United 

 States was 30,000,000 tons. This enormous increase is un- 

 doubtedly due to the extended use of coal-cutting machinery. 

 In the United States 23 per cent, of the total output of coal was 

 mined by machinery. Only a little more than i| per cent, of 

 the output was so obtained in Great Britain. The path of 

 progress is, therefore, clearly indicated to British colliery 

 owners. 



As gold producers the British possessions take the first place, 

 and, thanks to the increased output of Canada and of Western 

 Anstralia, the British Empire reached a total of 5,475,000 

 ounces, or more than one-third of the world's supply. One- 

 fourth of the world's salt, and more than half of the tin, are 

 produced by the British Empire. On the other hand, the pro- 

 duction of copper, lead, petroleum, silver and zinc is small in 

 comparison with the world's output. The magnitude of the 

 petroleum industry is surprising in view of the fact that its 

 growth has been within the last half of the nineteenth century. 

 The chief producing countries were : — Russia with 8,340,000 

 tons, the United States with 7,247,000 tons, Austria-Hungary 

 with 325,000 tons, Roumania with 313,000 tons, and the Dutch 

 East Indies with 217,000 tons. The United States has had to 

 cede to Russia the .position it so long held as first in the 

 production of petroleum. 



In 1899 the Transvaal was the greatest gold-producing 

 country of the world, the output representing a value of 

 16,273,000/. Owing to the war, detailed statistics for 1899 are 

 not available. In Cape Colony the outbreak of the war in 

 October caused a rapid decrease in the output of the coal mines, 

 and eventually stopped nearly all of them. In Natal, again, 

 coal-mining was interfered with, and no official report for 1899 

 has been received. In Rhodesia, on the other hand, gold- 

 mining made remarkable progress. The output of gold was 

 65,304 ounces in 1899, whilst in the previous year it was 

 18,085 ounces. The mining prospects of the country are cer- 

 tainly very satisfactory, more especially as the search for coal is 

 giving most promising results. 



The copious references to original sources of information 

 given by the editor in footnotes form a very valuable feature of 

 the report. In this connection it is noticeable that in his 

 capacity of juror at the Paris Exhibition Dr. Le Neve Foster 

 has had access to numerous special reports which, but for his 

 assiduity, would hardly have come to the knowledge of English 

 engineers. The great development of the iron ore resources of 

 Luxemburg during the last thirty-two years, for example, was 

 clearly illustrated in a table shown at the Paris Exhibition. In 

 1868 the output of iron ore was 691,000 tons, whilst in 1899 

 it was 5,995,000 tons. At another place in the volume the 

 latter figure is given as 6,014,000 tons, there being apparently 

 a slight discrepancy between the figures obtained by the Home 

 Department of the Grand Duchy and by the German Customs 

 Union, of which Luxemburg forms part. The political classi- 

 fication of the various States is in several cases a matter of 

 difficulty, and has been attended to by Dr. Le Neve Foster 

 with scrupulous care. It is possible, however, that in dealing 

 with Austria and Hungary under one heading, while Sweden 

 and Norway are dealt with separately, he will oause offence to 

 the ultra-patriotic Magyars. Since the compromise between 

 the two States, renewable every ten years, was not renewed in 

 1897, the Union is merely personal through the Emperor and 

 Apostolic King, and in order to make it evident that Hungary 

 is not a vassal State, the official denomination of the Austro- 

 Hungarian Monarchy is to be preferred to the term Austro* 

 Hungarian Empire used in the report. 



