720 



SCIENCE. 



[N. S. Vol. IV. No. 98. 



plosion of a fulminate, does not propagate 

 itself to an appreciable distance. Hence it 

 would seem that local acetylene generators, 

 where the gas is not exposed to a pressure 

 much above that of the atmosphere, are 

 free from danger of explosion. When, 

 however, the pressure on the gas is greater 

 than two atmospheres, the decomposition 

 induced by an incandescent wire, or other- 

 wise, is propagated through the whole mass, 

 the rapidity of propagation and the pres- 

 sure of explosion increasing rapidly with in- 

 creased initial pressure. Thus acetylene, 

 at a pressure of twenty-one atmospheres, 

 when exploded, generated a pressure of 

 two hundred and twelve atmospheres and 

 a calculated temperature of 2750° C. The 

 acetylene is decomposed quantitatively into 

 hydrogen and compact amorphous carbon. 

 Acetylene condensed to a liquid may be 

 similarly exploded by spark, incandescent 

 wire, or detonator, and in one experiment 

 18 grams of acetylene exploded in a bomb 

 of 49 c.cm. capacity showed a pressure over 

 5000 atmospheres, an explosive force about 

 that of gun cotton. Experiments as to the 

 effect of shock showed that acetylene is not 

 thus exploded. In one case where the re- 

 ceptacle was broken by the shock, the ac- 

 etylene was ignited, evidently by the fric- 

 tion of the shattered pieces, the mixture of 

 the liberated acetylene and air forming an 

 easily ignited explosive mixture. In this 

 case no carbon was deposited, the gas burn- 

 ing and not decomposing. There seem to 

 be two prominent dangers in compressed 

 acetylene : the heat generated in the rapid 

 compression of the gas may be suflBcient to 

 explode it ; in case of fracture of the recep- 

 tacle the explosive mixture of acetylene 

 and air may be ignited by friction. 



The authors conclude that the advantages 

 in the use of the gas more than compensate 

 for the dangers attending its use, which, 

 with sufficient care, may be reduced to a 

 minimum. 



Another question has been raised regard- 

 ing the use of acetylene which is not touched 

 upon in this article. Acetylene forms, with 

 certain metals, very explosive compounds. 

 Whether in its use as an illuminant there 

 is danger of such compounds being formed, 

 is a point which deserves investigation. 



In the last Chemical Neivs, Dr. Geo. F. 

 Payne, of the Georgia Department of Agri- 

 culture, offers a just criticism of a statement 

 in the last edition of Blyth's ' Poisons.' Dr. 

 Blyth states that cotton seed is poisonous to 

 animals, and its use as an adulterant of lin- 

 seed cake has caused the death of sheep 

 and calves. Dr. Payne calls attention to 

 the extended and successful use of whole 

 cotton seed, cotton- seed meal and cotton- seed 

 hulls in the South for fattening cattle, and 

 suggests that the cases cited by Dr. Blyth 

 may be due to castor-oil pomace, either ac- 

 cidentally mixed with the cotton-seed meal, 

 or in a mixture intended for fertilizing pur- 

 poses and inadvertently used for feeding 

 animals. 



In the recently published second edition 

 of ' The Cj'anide Process of Gold Extrac- 

 tion,' by James Park (Auckland, N". Z., 

 Champtaloup and Cooper), it is stated on 

 the authority of Johann Antal, a Hunga- 

 rian toxicologist, that a solution of cobalt 

 nitrate is a perfect antidote to cyanid poi- 

 soning. A matter of so much importance 

 if true, deserves very careful investigation 

 and confirmation. J. L. H. 



ASTRONOMICAL NOTES. 

 The Astronomical Journal of October 16th 

 contains a determination by Mr. Eric Doo- 

 little of the secular perturbations of Mer- 

 cury arising from the action of Jupiter. 

 Gauss's method was employed. 



In the Astronomische Nachrichten of October 

 8th Dr. Marcuse, of Berlin, publishes an 

 account of the new photographic zenith 

 telescope recently constructed for the Geo- 



