On the Gas Blowpipe. :i3l 



would seem, where the highest heat is desired, evidently ab?iird 

 to employ them in any other way; because, if either gas were pre- 

 sent in too great a quantity to be acted upon, the excess would 

 be worse than useless. Is it not universally an object with che- 

 mists, to use ingredients in the proportions in which they saturate 

 each other, especially when within a given space and time tlie 

 most intense reaction is to be induced ? The author of this pro- 

 fessedly candid publication would wish to convey the idea of my 

 contrivance being so inferior in power to that adopted by him, 

 that in a history of the invention he does not deem it necessary 

 to quote my experiments, but satisfies himself with obscure allu- 

 sions to them, rather in a manner to derogate than to do justice. 

 This procedure would be unjustifiable, were the heat which he 

 has produced decidedly greater than that produced bv me. But 

 the fact is otherwise. He fuses with difficulty oolite, Iceland 

 crystal, and pure native magnesia. The fusion of the best mag- 

 nesia of the shops, and of quick lime from pure limestone, w.is 

 among my first efforts, and was mentioned in a preface, omitted 

 in republishing my memoir. Lately I have fused a piece of ovster- 

 shell lime, which is perhaps as pure as any to be obtained by 

 artificial purification. 



Dr. C. has employed platina in some cases to secure refractory 

 earths while exposed to the action of his instrument, although 

 this metal is dissipated by the heat of mine. 



That in his inferences in respect to the decomposition of the 

 earths, he did not anticipate Professor Silliman or myself, must 

 be evident from the passages in our memoirs which I shall pre- 

 sently quote. I doubt, if time will show that Dr. Clark has 

 gone nmch beyond ihe extent of our observations on this sub- 

 ject. 



But while the superiority of the temperature attained by mix- 

 ing the gases before emission is thus questionable, there arc great 

 and undeniable advantages in having them propelled from dif- 

 ferent reservoirs. First, A degree of security from explosion, 

 which cannot be attained with one common recipient*. 2d, The 



• \\niere the gases are kept unmixed in separate reservoirs, and meet 

 only near the point of efflux in an orifice sufficiently large, as was the case 

 with the orij^inal compound blowpipe, explosion is obviously impossible. If 

 the orifice be made smaller, and the gases mix at a greater distance from 

 tlie place of efflux, valves should be interposed in the pipes, or the gases 

 should be kept under equable pressure, as it is possible that, if subj(;cted to 

 unequal pressure, the gas whicii is more pressed may pass Iroin one reservoir 

 to the other, on leaving the cocks open accidentally. This, however, is an 

 oversight not likely to take place, as it is so evidently accompanied by a 

 waste of the gas, that an operator will hardly be so careless as not to close 

 the cocks when tlie flame is not wanted. Closing thcni is in fact the usual 

 mode of extinguishing the flame. 



T t 2 possibility 



