Proceedings of the Polytechnic Association. 1009 



burning gases, and consequently the temperature of tlie flame is low- 

 ered ; the same amount of heat will evidently impart a higher tem- 

 perature to one pound of material than it will to live pounds, just as 

 sa kettle half full will boil more quickly than a kettle entirely filled. 

 A very ingenious gentleman of western N"ew York, Dr. George H. 

 Smith, acting on this principle, adopted the plan, using common air 

 and common gas for producing the oxy-hydrogen light, biit^ he heated 

 the gases before bringing them together. In this manner he attained 

 a starting point so far in advance of that secured by the previous 

 methods that the final temperature given out by the flame was abund- 

 antly capable of producing an intense light. In the Budedight, the 

 temperature of the luminous portion of the flame is increased, pro- 

 vided there be not introduced so much oxygen as will combine with 

 all tlie luminous'material of the flame before its light giving proper- 

 ties are evolved. Where oil lamps are used, the m.anipulation is 

 easy, but where coal gas is employed, the relative pi-essures of the coal 

 gas and oxygen must be carefully regulated, or failure is the result. 

 If Dr. Tanderweyde shoidd bring a supply of oxygen . to our next 

 meeting, I will try to reproduce the experiment. 



Aluminium Broxze. 



This beautiful alloy, which closely resembles gold, a'nd which 'is 

 composed of nine parts of -copper with one of ftluminum, is rapidly 

 making its way in the arts. M. Dumas stated to a late meeting of 

 the French. Academy of Sciences that this bronze was now &itccC;s>s- 

 fully used in various kinds of mechanism, especially in saws driven 

 by steam power, which saws, although much thinner, lasted a mu«h 

 longer time than those of steel. It lias also been applied with 'great 

 success to the construction of journals in machinery intended ^to be 

 run at a high speed. ^ 



Dr. L. Feuchtwanger presented a spechnen which he had. carried 

 in his pocket for some years. 



Valuable Preservative PREPARATioif. 



Although the useful properties of carbolic acid are wedl known, its 

 use has not been extensive on account of its objection^fele odor. To 

 remove the odor, Dr. Harris, health ofiicer of New York, recom- 

 mended camphor. Two parts by weight of gum camphor may be 

 added to one part ^i carbolic acid in crystals. These solids, on 

 being rubbed together for a few minutes, form a. liquid. It is a pow- 



[Inst.] ~ 64: 



