jcs Memoir on the Supply and 



combuftion, and of the mo(^ fpeedy mixture with the oxi- 

 datina" princijile when arrived there. 



The opinion oFthe intenleuels of the heat produced by the 

 hvdrogen and o.wgcn gafes thus upheld bv theory, derives 

 additional fiipport from the praflical obfcrvation of the great 

 heat of a flame fupported by hydrogen gas while iflfuing from 

 a pipe; and alfo of the violent explofion which takes place 

 when it is mixed with oxygen gas and ignited; for it appears 

 that this explofion can only be attributed to the combination 

 o\. an immenfe quantity of caloric with the water which is 

 either held in folution by thefe gafes, or formed l?y the union 

 of their bafes. 



Such was the reafoning which originated the defire of em- 

 ploying the flame of the hvdrogen and oxygen gafes. But 

 before this could be accompliflicd it was neccfl^'ary to over- 

 come the difliculty of igniting a mixture of thefe aeriform 

 fubftanccs without the danger of an explofion. It was for 

 the purpofe of furmounting this difficulty that the hydroftalic 

 blow-pipe was furniflied with two compartments, by means 

 of which the machine might be at the fame time charged 

 with different fpecies of air, without any poffibility of mix- 

 ture. One of thefe compartments being fupplied with oxy- 

 gen and the other witli hydrogen gas, two common brafs 

 blow-pipes a, b, fig. 8, were joined at their orifices to two 

 tubular holes in the conical fruftum of pure lilver c, of which 

 the mean diameter is one-third, and the length is three- 

 fourths of an inch. The diameter of one of thefe holes is- 

 large enough for the admlffion of a common brafs pin. The 

 other hole is a third lei's. They commence feparately on the 

 upper furtace of the filver fru(hmi near the circumference, 

 and converge fo as to meet in a point at the diftance of a line 

 and a half from the lower furface. In the fpace between 

 the lower lurface and the point of meeting, there is a per- 

 foration of the fame diameter as the larger hole. The man- 

 ner in which this perforation and the tubular holes commu- 

 nicate one with the other, may be nnderftood from the lines 

 in the form of the letter Y, in the tranfparent rcprefentation 

 of the filver conical frulhim at d. The pipes ab were then 

 fitted into the mouths O, o, of the pipes of delivery, fig. i ; 

 fo that the blow- pipe infertec! into the larger hole of the fruf- 

 tum fliould communicate with tlie compartment containing 

 the hydrogen gas, and that the other fliould communicate 

 •with that which contained the oxvgen gas. The cock of the 

 pipe communicating with the hvdrogen gas was then turne4 

 until as much was emitted from liic orUice of the cylinder 



as 



