14 



SCIENCE 



[N. S. Vol. XLIII. No. 1097 



tlie largest previous production and eighteen 

 per cent, above last year's figures. Only twice 

 in the history of copper mining has there been 

 a larger increase in quantity of metal produced. 



The total shipments of iron ore from the 

 mines in the United States in 1915 are esti- 

 mated to have exceeded 55,000,000 gross tons, 

 an increase over 1914 of more than 38 per cent. 

 Based on the same price as received in 1914 

 this represents an increase in total value of 

 about $27,645,000. The increase in pig iron 

 is estimated at 6,500,000 tons, with a total in- 

 crease in value of pig iron production of more 

 than $120,000,000. 



The output of zinc (spelter) made from 

 domestic ores was larger than ever before, 

 being about 425,000 tons, worth $120,000,000 as 

 compared with 343,418 tons in 1914, an in- 

 crease of about 82,000 tons or nearly 25 per 

 cent, in quantity and of $85,000,000 in value. 

 Production was increased during the latter 

 half of the year, as the production during the 

 first half was at the rate of 415,000 tons an- 

 nually and at the rate of 436,000 tons during 

 the last half. 



The output of refined pig lead from domestic 

 ores was about 515,000 tons, worth about $48,- 

 500,000 as compared with 512, Y94 tons in 1914, 

 an increase of only 2,500 tons in quantity but 

 of $8,500,000 or 20 per cent, in value. The 

 production of antimonial lead was 20,550 tons 

 as compared with 16,668 tons in 1914, an in- 

 crease of 3,882 tons or 23 per cent, in quantity 

 and an increase in value of nearly $2,000,000. 



The annual preliminary estimates on the 

 production of gold and silver in the United 

 States, made jointly by the United States Geo- 

 logical Survey and the Bureau of the Mint, are 

 not yet complete, but early figures based on 

 reports from the mines indicate an increase in 

 mine production over that of 1914 of over 

 $7,000,000 in gold, principally from Colorado, 

 California, Alaska, Montana and Idaho, and 

 an increase in mine production of silver of 

 fully 4,000,000 ounces, ehiefiy from Montana, 

 Utah and Arizona. This increase in gold pro- 

 duction may bring 1915 up to the record year 

 of 1909, when the gold output of this country 

 was nearly $100,000,000. 



Quicksilver also has had its best year in 

 1915. The quantity increased 25 per cent, over 

 1914, but the value of the output more than 

 doubled owing to the much higher prices. The 

 estimated production was 20,681 flasks of 75 

 pounds each, valued, at the average price for 

 the year — the highest in the last forty years — 

 at $1,768,225. In value, this domestic produc- 

 tion was the highest since 1881 and in quan- 

 tity the largest since 1912. 



The production of bituminous coal and 

 anthracite in 1915 is estimated to have in- 

 creased between four and five million short 

 tons, or less than 1 per cent. The quantity of 

 bituminous coal mined increased about 64 

 million tons and that of anthracite decreased 

 over two million short tons. Owing mainly to 

 steady demands for erport coal and for coke 

 for steel making, the output in Pennsylvania, 

 West Virginia, Kentucky and Alabama in- 

 creased over last year, but little change is re- 

 corded in other eastern states. The region 

 west of Ohio, including the Mississippi Valley, 

 shows a general decrease, Colorado being the 

 only western state to show betterment. 



Connected with the coke industry was the 

 completion during the last summer of a num- 

 ber of large plants for the recovery of benzol 

 from by-product coke-oven gas. This gives 

 the United States its first output of this mate- 

 rial, so important as a raw material in the 

 manufacture of high explosives and chemical 

 dyes, and the amoimt of this product will be 

 reported later. 



Preliminary estimates of the total output of 

 petroleum in the United States in 1915 indi- 

 cate a slight increase over the corresponding 

 output in 1914. It is believed that the total 

 petroleum yield of the United States in 1915 

 amounted to 291,400,000 barrels, of which 

 quantity it is also estimated that 267,400,000 

 barrels was marketed and 24,000,000 barrels 

 placed in producers' field tankage during the 

 year. 



The sulphuric acid industry in 1915 pre- 

 sented interesting development. In spite of 

 the abnormal demand and higher prices in the 

 latter half of the year, much of the sulphuric 

 acid had been contracted for or was con- 



