204 ANNUAL OF SCIENTIFIC DISCOVEKY. 



Phonic acid is now much talked about as a disinfectant, and 

 especially in connection with the rinderpest. But its virtues as a 

 disinfectant are douljtful. It promptly prevents the decomposi- 

 tion of matter whicli generates foul odors, but it acts slowly and 

 f»oorly on the odors already existing. If it destroys an odor, it 

 eaves itself in the "jjlace of it, and, to most pc^ople, will smell 

 quite as bad. Tlie lirst odor of i)henic acid is toleral)le, Init whea 

 continued, it becomes exceedingly unbearable. — Scieniijic Amer- 

 ican. 



HOW TO MAKE NITROGLYCEEINE SAFE. 



Prof. C. A. Sceley makes the following communication to the 

 ♦' Scientific American " : — 



In an article on this subject in the " Scientific American" of 

 May o, I made the assertion that tlie dangers from nitroglycerine 

 are ])reveiit.il)k', and tliat sure means were known Ity wliicli its 

 transportation and storage could be made safe. I shall now 

 diiscribe the most perfect of the plans proposed, and I ask tiiat 

 those who are interested in tlie subject will carefully weigh them. 



1. Mr. Nobel proposes to dihite tlie nitroglycerine with wood 

 naphtha. Tliese two liquids mingle in auy iiroportion, and the 

 explosibility of the mixture may be reduced to any desired extent. 

 Probal)]y a mixture containing aljout twenty-live per cent, of 

 naplitha could not be made to explode by percussion, or gradual 

 beating. When tiie nitroglycerine is re(iuired for use, water is 

 added to the mixture, and takes from it the naphtlia, while the 

 pure nitroglycerine sinks to the bottom. Tiiis jilan is, however, 

 liable to serious objections. (1.) The expense of the naphtha and 

 loss of nitroglycerine in washing with water. (2.) The volatility 

 of the naiiiitlia: whenever the mixture is exposed to air some of 

 the naphtha escapes, anil the nitroglycerine migiit be iett unpro- 

 tected. (3.) It is prol)able tliat there would be a chemical action 

 between the suljstances. (4.) The na))litlia and tlie vapor from it 

 are very combustible. The vapor mixed with air would be an 

 explosive mixture. 



2. It has been proposed by several persons, quite independently 

 of eacli other, to keep the nitroglycerine mixed with sand, or other 

 inert substance, which would serve as a conductor of heat, in the 

 same way as the glass powder in Gale's gunpowder mixture. This 

 plan would greatly increase the weight and bulk of packages, and 

 great loss would be sustained by reason of the adhesion of the 

 nitroglycerine to the sand. 



3. Dr. Henry AVurtz proposes to make a thorough mechanical 

 mixture or emulsion of tlie nitrogh'cerine with a saline solution of 

 the same specific gravity. A solution of nitrate of zinc, lime, or 

 magnesia, will probably be found to be suitable. When the nitro- 

 glycerine is needed for use, water is added to the mixture, when 

 the oil subsides and may be drawn off. Further experience seems 

 to be needed to determine how long the mLxture may be main- 

 tained without spontaneous separation. 



4. I have proposed to prepare the nitroglycerine more carefully, 

 in order that it shall be perfectly freed from acid ; and, to prevent 



