4^0 X)r. Clarke upon the Gas Blowpipe, [June, 



result of fusion possessing properties of a peculiar nature. It 

 differs from wood-tin, which exhibits, after fusion, the same 

 degree of metallic lustre, but is still in the state of an oxide. 

 Being guided by no other views than those which may con- 

 duce to the interests of science and the advancement of 

 truth, after once more caUing the attention of your readers 

 to a subject not unworthy of their regard, it is my inten- 

 tion to consign to them its future and further consicleration; 

 briefly adding what, in the course of the last five years of expe- 

 rience, I have discovered to be the cause of failure in the 

 tittempts made for obtaining this effect of fusion in harytes ; and 

 moreover a few remarks upon some other curious phenomena 

 which the use of the gas blowpipe has developed. 



In the first accounts which I pubHshed of experiments with 

 tliis blowpipe, the propriety of mixing the oxygen and hydrogen 

 gases in the exact proportion for forming water was always 

 insisted upon ; because, when the hydrogen gas is only added in 

 slight excess, tlie mixture either will not burn at all, or the tem- 

 perature of the flame is greatly diminished ; upon the elevation 

 of which temperature the success of many experiments depends. 

 There are some experiments for which only hydrogen gas alone 

 may be employed combined with a small portion of atmospheric 

 air ; or hydrogen gas uncombined with any other aeriform fluid ; 

 but the temperature is then greatly lowered ; and hence may be 

 perceived the impropriety of naming this instrument the 

 oxy-hydrogen blowpipe ; because it is adapted to gases of all 

 kinds ; whether in a state of explosive mixture or not ; some 

 being used, as, for example, oxygen gas, not for combustion, but 

 merely as a supporter of combustion, to propel the flame of a 

 combustible body, as alcohol. It is on this account that I have 

 preferred calling it the gas blowpipe ; being an appellation of a 

 more general nature ; applicable, not only to the use which I 

 have made of it in burning the gaseous constituents of water, 

 but to all its operations with condensed gases of whatsoever 

 nature they may be. But to return : I have since found that 

 for communicating the utmost elevation of temperature to the 

 flame of mixed oxygen and hydrogen gases, it is better to add the 

 ^^c?rogew gas in greater excess than was at first thought to be neces- 

 sary : instead of two parts by bulk of hydrogen to one of oxygen, 

 the proportion o^ nine to four is greatly to be preferred ; as, for 

 example, nine pints, or measures, oi hydrogen gas, to four pints, 

 or measures, of oxygen gas.* The operator upon opening the 

 valve, to set fire to this mixture, will immediately perceive how 

 much more explosive it is than any other ; by the rapid snap- 

 ping noise of the flame, caused by successive detonations at the 

 mouth of the jet, while he is lighting the gas with a paper, and 



♦ This proportion ought especially to be observed when the oxygen gas has been 

 obtained from the oxide of manganese., and the hr/drogen gat from the decomposition of 

 mattr by ironings acted upon hy fnf^huric a<;id. 



