380 



SCIENCE. 



[N. S. Vol. III. No. 63. 



aluminum and its alloys and perhaps other 

 metals. N"o mention is made in the reports 

 of carbide of calcium nor of acetylene. 

 Dickerson and Suckert, December 31, 1894, 

 nine months after Moissan's publication, 

 patented a process for evolving and con- 

 densing acetylene made from the carbide of 

 calcium. And June 18, 1895, is the date of 

 the first patent by T. L. Willson in which 

 the report specifies the production of car- 

 bide of calcium. 



Many statements have been published 

 concerning commercial aspects of the new 

 enterprise, but it will suSice to say here 

 that it has not yet reached a stage at which 

 the vital question of the cost to the con- 

 sumer of the carbide of calcium can be fixed 

 by the quotation of a market price. Small 

 quantities can be purchased for experimen- 

 tal purposes in New York at a price of $5 

 per 100 lbs. But the manufacture in the 

 United States does not exceed one ton per 

 diem and is carried on at Spray, in North 

 Carolina, a somewhat inaccessible place, 

 and no complete account of the process has 

 yet appeared in the best-known scientific 

 periodicals. The commercial carbide, un- 

 like that made by Moissan, probably con- 

 tains compounds of calcium with the ash of 

 coke, but no complete analysis has been 

 published. Some of the statements made 

 about the number of cubic feet of acetj'lene 

 are obviously inaccurate because the figures 

 5.89 to 6.35 cu. ft. acetylene per lib. cai-- 

 bide are as high or higher than could be 

 obtained if the carbide contained no ash 

 and were absolutely pure. 



The accurate measure of the gas given of? 

 by the carbide is not easy and requires the 

 construction of a special apparatus. The 

 writer has examined a number of samples 

 of commercial carbide, and found that 70 to 

 92 per cent, of the theoretical quantity of 

 acetylene could be obtained from them. It 

 appears that the product which can be made 

 to the best advantage is one which contains 



8-4.6 per cent, of pure carbide, and which 

 gives 5 cu. ft. of gas per pound ; or, for a ton 

 of carbide, 10,000 cu. ft. acetylene, two-thirds 

 saturated with moisture, and measured at 

 60° Fahr. and 30 inches barometer. Sum- 

 mer and winter variations of temperature, 

 together with barometric variations, would 

 cause a difference of more than 15 per cent, 

 in the uncorrected measure of the gas, and 

 gas measured in a mountainous region, with- 

 out correction for the low barometer, would 

 differ far more from the standard amount. 



If the acetylene industry shall succeed, 

 the cost of the. carbide will have to be ad- 

 justed to the price that the consumer may 

 be willing to j)ay for gas, and it is prefer- 

 able to treat the subject from this side and 

 to show, as far as laboratory experiments 

 with materials at hand will permit, what 

 will be the probable value to the consumer 

 of acetylene gas. 



A very simple experiment illustrates in a 

 beautiful way the ease with which acetylene 

 can be made from the carbide. Direct a 

 small stream of water on a half-pound lump 

 of carbide, ignite the gas and show that the 

 more water is poured on, the more flame is 

 obtained. Various forms of generators can 

 be used for the gas. The simplest one is a 

 bell glass floating on water and containing a 

 few lumps of carbide in a sieve. As soon as 

 the bell glass descends so that the sieve 

 touches the water, a shower of fine sediment 

 of slaked lime can be seen to se^jarate from 

 the carbide and fall to the bottom of the jar, 

 while the gas generated soon causes the bell 

 to rise and removes the carbide from contact 

 with the water. Thus the apparatus can be 

 made to work automatically, generating 

 gas only as fast as it is used ; but it is not 

 fitted for permanent use, because the moist- 

 ure from the water generates gas, even 

 when the contact has ceased, and the bell 

 gradually rises, so that after twenty-four 

 hours gas would escape if it were not used 

 during the interval. 



