Septembeb 4, 1908] 



SCIENCE 



303 



necessary for some years to come if sleeping 

 sickness is to be stamped out of the country. 



The United States not only produced 96.6 

 per cent, of all the salt consumed within its 

 bordei-s in 1907, but exported nearly 62,000,- 

 000 pounds, valued at more than a quarter of 

 a million of dollars, according to W. C. Phalen, 

 whose report on the salt and bromide industry 

 of this country for the last calendar year has 

 just been published by the U. S. Geological 

 Survey. The salt production of the IJnited 

 States in 1907 amounted to 29,704,128 barrels 

 of 280 pounds, valued at $7,439,551— an in- 

 crease of 1,531,748 barrels in quantity and of 

 $781,201 in value over the output in 1906. The 

 average net value of the product in 1907 was 

 $1.79 cents per short ton, as against $1.69 

 per ton, in 1906, an increase for 1907 of 10 cents 

 per ton. In both quantity and value of out- 

 put the United States stands at the head of 

 the salt-producing countries of the world. 

 In quantity the United Kingdom, the Ger- 

 man Empire, and France rank next, in the or- 

 der given, although the value of both the 

 German and the French output exceeds that 

 of the United Kingdom. 



A TOTAii output far in excess of that of any 

 previous year or any other country, an un- 

 paralleled accumulation of stocks, and 

 high prices for oil of all grades char- 

 acterized the petroleum industry of the 

 United States in 1907, according to David T. 

 Day, of the United States Geological Survey. 

 The total production of petroleum in this 

 country in 1907 amounted to 166,095,335 bar- 

 rels, an increase of 39,601,399 barrels over 

 the production of 1906, the increase being 

 greater than the total product of petroleum 

 in any year up to 1889. The total value in- 

 creased from $92,444,735 in 1906 to $120,106,- 

 749 in 1907. The average price decreased 

 slightly, from $0,731 per barrel in 1906 to 

 $0,723 in 1907. 



The London Times states that long before 

 the flight of his fourth airship Count Zeppe- 

 lin had been laying his plans for the con- 

 struction of his fifth balloon. Ten or twelve 

 weeks ago he entrusted Messrs. C. G. Spencer 

 and Co., the well-known manufacturers and 



aeronauts of Highbury, with the task of ma- 

 king the balloon fabric. The work is in fuU 

 progress in the works at Highbury. In the 

 factory a number of girls are engaged in pre- 

 paring the goldbeaters' skin from which the 

 Zeppelin balloon No. 5 is to be made. The 

 envelope will be composed of six layers of the 

 skin, and by a process known only to the 

 firm the skins are so joined together that no 

 seams are visible, and the finished fabric com- 

 bines extreme lightness with an extraordinary 

 degree of toughness. Mr. Spencer said that 

 the cells, or gas holders, of No. 5 balloon were 

 being built like a very large drum, and were 

 divided into 15 sections, each being self-con- 

 tained. The holding capacity of these would 

 be 40,000 cubic feet, so that the whole balloon 

 ■ — 600,000 feet — would be considerably larger 

 than that of No. 4. There would be sufficient 

 room in the building for the inflation of each 

 section separately. The sections would then 

 be packed carefully and sent to Germany to 

 be fitted into the rigid framework of Count 

 Zeppelin's airship. Mr. Spencer said that 

 this goldbeaters' skin is the strongest mater- 

 ial for its weight that could be found. Hith- 

 erto Count Zeppelin had relied, he said, upon 

 an indiarubber-covered fabric, but though 

 this is cheaper it is three or four times heav- 

 ier. It is estimated that the skins of about 

 600,000 cattle will be required before the 

 work is finished. The firm expects to finish 

 the fabric in about a fortnight. 



AccoHDiNG to a report recently issued, the 

 total number of visits recorded as having been 

 made by the public to the Natural Histoiy 

 Museum (London) during the year 1907 was 

 497,437, as compared with 472,557 in 1906— 

 an increase of 24,880. The number of visits 

 on Sunday afternoons was 66,367, as against 

 61,151 in the previous year. The average 

 daily attendance for all open days was 1,370.3 ; 

 for week-days only, 1,386; and for Sunday 

 afternoons, 1,276.3. The total number of gifts 

 received during the year by the several de- 

 partments of the museum was 2,105, as com- 

 pared with 2,057 in 1906, among the donors 

 being the Egyptian government (an important 

 series of fishes from the Nile) ; the Prince of 



