Maech 10, 1899.] 



SCIENCE. 



355 



peratures vaiyiag for the liquids from 3S°F. 

 to 60° F. and for the earths from 32 °F. to 

 60°F. Mr. George B. Selden, p. 178, 

 found the mixture of naptha and air in the 

 best proportions, to give, on explosion, a 

 pressure of 140 pounds per square inch, 

 while coal gas and air in the best propor- 

 tions gave 160 pounds per square inch, and 

 that the ignition point of the naphtha mix- 

 ture was 950°C. while that of the coal gas 

 mixture was 800°C. 



I have already referred to the means 

 taken for ensuring the removal of the more 

 volatile hydrocarbons from domestic kero- 

 sene, a subject which has been very exhaus- 

 tively treated by Rudolph Weber.* It has, 

 however, been seriously stated that the 

 lighter oils, such as benzoline or naphtha, 

 might be rendered safe for use in lamps 

 by adding alum, sal ammoniac or camphor 

 to them, and many innocent persons have 

 suffered in consequence of their belief in 

 the efficacy of these substances. Some 

 years sincef I tested the effect of these bod- 

 ies by determining their solubility in ben- 

 zoline, the flashing points of benzoline and 

 commercial kerosene when treated with 

 these bodies and when in their original 

 state, and also the readiness with which 

 mixtures of the oils, in the two conditions, 

 with air could be exploded. The results 

 showed that alum and sal ammoniac were 

 practically insoluble in the oils and pro- 

 duced no effect whatever upon them ; that 

 the camphor was soluble, one gram of ben- 

 zoline dissolving about 1.5 gi'ams of cam- 

 phor ; that an equal weight of camphor 

 raised the flashing point of a kerosene 12° ; 

 but that, on the other hand, the vapor of 

 this camphorated kerosene, when mixed 

 with air, had a lower point of ignition, and 

 hence exploded with greater readiness than 

 the original kerosene. 



What is true regarding the use, storage 



*Ding. poly. J. 241, S77 and 383; 1881. 

 \Proc. A. A. A. S. 33, 174; 1885. 



and transportation of petroleum products 

 holds for other easily volatile liquids. 

 Professor Thomas Graham, in his report* on 

 the cause of the loss of the ' Amazon' on 

 January 4, 1852, pointed out clearly the 

 danger in transporting turpentine, while 

 the destruction of the ' Livadia, ' of Liver- 

 pool, May 11, 1891, carrying a cargo of car- 

 bon disulphide, emphasizes the hazard at- 

 tending this substance, for this heavj- and 

 very mobile liquid gives off quite rapidly 

 at ordinary temperatures a vapor which is 

 2.64 times heavier than air, and which not 

 only readily collects at the bottom of any 

 space in which it is produced, but follows in 

 a stream like water. 



One of the more striking characteristics 

 of the mixture which this vapor forms with 

 air is its low point of ignition. The tiniest 

 spark ; a cinder after it has ceased to glow, 

 or the striking together of two pieces of 

 iron without sparking, are sufficient to de- 

 termine its ignition. This property may 

 be exhibited by plunging a glass rod heated 

 to 231° C, (450° F.) (a temperature at 

 which it can be touched with the bare hand) 

 into the mixture. 



The use of ether, alcohol, acetone and al- 

 dehyde, with nitroglycerine and guncotton, 

 for the manufacture of smokeless powders, 

 and of the esters as solvents for pyroxylin 

 in the making of the varnishes that are 

 largely used in household decoration, are 

 some of the more modern forms of hazard, 

 while the explosion at the Hotel Endicott, 

 in ISTew York, and at Newark, N. J., indi- 

 cate what may be expected from the more 

 extended use of liquefied air and liquefied 

 acetylene. 



Although Dr. John Clayton, the Dean of 

 Kildare, in the sixteenth century, effected 

 the destructive distillation of coal and col- 

 lected and burned the gas from it, f it was 



* Spontaneous Combustion and Explosions occur- 

 ring in Coal Cargoes, Tiiomas Rowan, p. 40, 1882. 

 t Treatise on Coal Gas, William Eichards, 1877. 



