546 



Mr. Bowman on Tribasic Boracic Mther. 



88-56 



99-19 



99-97 



99-99 



100-10 



100-36 



100-79 



Professor Bunsen has been so kind as to communicate to me 

 the following very interesting series of experiments relating 

 to this subject, proving clearly that the formation of nitric 

 acid is diminished in the combustion of explosive mixtures 

 according to the dilution with atmospheric air. He mixed a 

 constant quantity of atmospheric air with a decreasing quan- 

 tity of pure explosive gas formed by decomposing water by 

 means of electricity, and obtained the following results on 

 combustion : — 



Vol. Vol. Vol. 



100 atmospheric air gave after combustion with 259-70 explosive gas 86-15 

 100 ... ... ... 226-80 



100 ... ... ... 84-98 



100 ... ... ... 63-21 



100 ... ... ... 48-98 



100 ... ... ... 40- 



100 ... ... ... 36-39 



100 ... ... ... 21-20 



100 air mixed with 11 vols, of explosive gas did not ignite. 



By this it is proved that the ignition of combustible gases 

 containing nitrogen must not be attempted at too far a limit 

 from the point at which the mixed gases are combustible. 

 This point may be ascertained with an unknown mixture by 

 previous experiment, as the gas before its separation from the 

 carbonic acid, &c. may be mixed with nearly double its vo- 

 lume of oxygen gas (which quantity is sufficient even if it 

 consisted of pure light carburetted hydrogen), and small por- 

 tions added by degrees to a known volume of atmospheric 

 air in an eudiometer until ignition by means of the electric 

 spark took place. For example, if it is found that 50 volumes 

 of such a mixture with 100 volumes of atmospheric air will 

 just ignite, then, according to the foregoing experiments, 

 treble the quantity of the former mixture may be ignited 

 without the formation of nitric acid. Therefore, in an eudio- 

 metrical analysis, the gas to be examined may be mixed with 

 twice its volume of atmospheric air, besides the requisite 

 quantity of oxygen gas. In this manner it is ascertained 

 Avhether the gas to be analysed requires still a dilution with 

 atmospheric air. 



LXXV. On Tribasic Boracic JEther. 

 By J. E. Bowman, Esq.* 



A FEW months ago M. Ebelmen published an account of 

 two compounds of silicic acid and aether, and announced 

 that by subjecting them to the gradual action of moist air, he 

 * Communicated by the Chemical Society; having been read May 18, 

 1846. 



