5H 



NATURE 



[January 6, 191 6 



should allow of the introduction of fresh pigs to 

 be treated immediately with serum. The com- 

 mittee is strongly impressed by the possibility 

 of artificial vaccination as a method of combating- 

 swine fever. It also recognises the advantages 

 that might accrue from the discovery of a trust- 

 worthy diagnostic test for obscure cases, and it 

 therefore recommends that investigation into this 

 and cognate matters should be actively continued. 

 Sir Stewart Stockman's report of his experi- 

 mental investigation is published with the com- 

 mittee's final report as an appendix, and it contains 

 most important discoveries, both on the question 

 of spread of the disease and concerning immuni- 

 sation. His proved conclusions on the various 

 aspects of the disease are very numerous, and so 

 very concise that it is impossible to condense 

 them any further for inclusion here. We may, 

 however, refer particularly to the proved exist- 

 ence of the "carrier." It has long been known 

 that a stallion recovered from influenza may con- 

 tinue to infect mares for a considerable period. 

 Stockman appears to have established the fact 

 that a boar, although apparently healthy, may 

 under similar conditions infect sows with swine 

 fever, and they in turn may pass it on to their 

 young. Such then are some of the difficulties of 

 tracing the spread of the disease, especially in 

 the case of an ultramicroscopic causal agent, and 

 in the absence of any known diagnostic agent for 

 obscure cases. 



The report and appendix indicate marked pro- 

 gress in our knowledge of the scourge. 



MINERAL PRODUCTS OF INDIA.^ 



WHILST he was director of the Geological 

 Survey of India, Sir Thomas H. Holland 

 instituted a system of quinquennial reviews of the 

 mineral production of India, beginning in 1898, 

 and these reviews have appeared regularly every 

 five years since 1903, practically upon the same 

 lines as originally laid down. Their appearance 

 is always a matter of interest to all students of 

 mineral statistics, whether their interest be 

 mainly scientific or mainly commercial, and the 

 present volume, covering the period 1909 to 1913, 

 contains much matter of importance from both 

 points of view. 



The two most important, economically, of the 

 mmeral products of India are coal and gold ; in 

 the five years ending 1908 the average annual 

 output of gold was valued at 2,266,307^., and 

 that of coal at 2,139,249;., so that the former was 

 the more important, in spite of the fact that the 

 period included the boom year 1908, when the 

 value of the coal output jumped up to more than 

 3»350)Ooo^- In the period now under review the 

 positions of these two items have been reversed, 

 the average value of the coal being 2,969,305?. 



1 "Records of the Geoloe'cal Survey of India." Vol. xlvi. (1915.) 

 Quinquennial Review of the Mineral Production of India. By Sir Thomas 

 H. Holland and Dr. L. Leigh Fermor. Revised for the Years 1909 to 1913, 

 by Dr. H. H. Hayden, Director, and Dr. L. Leigh Fermor, Superintendent, 

 Geological Survey of India Pp. 296 and Index xlvi. Published hy order 

 of the Indian Government. Calcutta : Office of the Geological Survey of 

 India; London: Messrs. Kegan Paul, Trench, Trubner & Co., 1915. 

 Price two rupees. ' 



NO. 2410, VOL. 96] 



per annum, and that of the gold 2,241,844/. It 

 will be noted that the gold output has been prac- 

 tically stationary throughout the whole decade ; 

 that of coal showed a drop in 1909 from the boom 

 year 1908, and then a steady increase up to nearly 

 3,800,000/. in 191 3, which may be taken as a 

 most satisfactory symptom, and as indicating that 

 the Indian coal trade is now on a firm and stable 

 basis. The output in 191 3 had reached a total of 

 16,208,000 tons, nearly double what it was ten 

 years previously, and of this large total nearly 

 one-third was consumed on the Indian railways, 

 which again is an indication of the prosperous 

 condition of the country as a whole. It is im- 

 portant to note, furthermore, that India has the 

 benefit of cheap fuel, the price at the pit's mouth 

 being only 45. 8d., or but little more than half 

 of what it is in this country. 



The accident death-rate for the five years under 

 review shows unfortunately a considerable increase 

 over the previous quinquennial period, namely, 

 I "38 lives lost per 1000 persons employed as 

 against 0*98 per 1000; even the former figure is, 

 however, lower than the average in Great Britain. 

 On the other hand, the output of coal per person 

 employed (below and above ground) shows a slight 

 improvement, namely, 109-4 tons as against 98'6, 

 this figure being about two-fifths of what it is in 

 the United Kingdom. It must not be forgotten 

 that a considerable amount of British coal is 

 machine-cut, whereas coal-cutting machines make 

 practically no headway in India on account of the 

 relatively cheap native labour. It is interesting 

 to note that two batteries of bye-product coke- 

 ovens have at last been installed on the Giridih 

 coal-field, capable of producing 40,000 tons of 

 coke and 400 tons of sulphate of ammonia an- 

 nually. It can only be hoped that further installa- 

 tions of such coke-ovens will be made, and that 

 Indian agriculturists will learn to appreciate the 

 value of sulphate of ammonia as a manure. 



Amongst other items of interest mav be noted 

 the commencement of operations of the' Tata Iron 

 and Steel Co. at their Sakchi works, in conse- 

 quence of which the production of iron ore in India 

 jumped up by about 300,000 tons in 1911. The 

 Barakar Iron Works also have replaced their 

 former somewhat uncertain sources of iron ore 

 supply by mines in the Manbhum and Singhbhum 

 districts, and are now smelting about 96,000 tons 

 of ore per annum. 



Lead and silver appear for the first time in the 

 table of mineral production, owing to the suc- 

 cessful operations of the Burma Mines, Limited, 

 at the ancient Bawdwin mines; the average 

 annual production has been just about 9,000 tons 

 of lead, carrying 80,000 ounces of silver, for the 

 past five years. 



Finally attention may be directed to the fart 

 that various mines of the Salt- Range have been 

 found to contain in places a not inconsiderable 

 proportion of potassium; some of the raw 

 materials contain more than 11 per cent, of this 

 element, and although its extraction presents some 

 difficulties, the problem appears to be quite cap- 

 able of solution. In view of the great demand 



