338 On the Gas Blowpipe. 



flame with a support of charcoal; they were evidently decom- 

 posed ; numerous distinct globules rolled out from them, and burned 

 with the peculiar vivid white light and flash which these metal- 

 loids exhibit when produced and ignited in the galvanic circuit. 

 It is hoped these hints mav produce a further investigation of this 

 subject. This communication has already been extended further 

 than was contemplated : but on concluding, it may be allowable 

 to remark that there is no body, in all probability, except a few of 

 the combustible ones, which is exemj)t from the law of fusion by 

 heat." 



Is there any apology for the manner in which Dr. Clark has 

 brought himself and his friend before the public on this su'>ject 

 without the smallest acknowledgements for these suggestions ? 



Clark's Gas Blowpipe, 

 In proceeding to state the revival of two of the metals of the 

 earths before the flame of the gas blowpipe, and of other metals un- 

 der similar circumstances, it may be proper to prefix the ingenious 

 theory of the Rev. J. Holme, of St. Peter's College, Cambridge, 

 respecting the cause of the decomposition that takes place. " It 

 is entirely owing to the powerful attraction which hydrogen has 

 to oxygen at such an exalted temperature." The reduction or 

 decomposition of oxides when exposed to the "gaseous flame*" 

 is therefore often instantaneous, and it is as instantly followed by 

 the combustion of the minute particles thus revived, and ulti- 

 mately by the decomposition of the regenerated oxide which is a 

 result of that combustion. Hence the coloured flame ; hence 

 also the appearance of an oxide in a state of incomparably ex- 

 treme division upon the supports used vvhether of metal or char- 

 coal ; an irrefragable test of the revival of the metal from whose 

 combustion this newly formed oxide has been derived. 



Experiments on Strontites. 



Hare, 1st part, Gth vol. American Philosophical Transac- 

 tions, page 100, republished Anvales de Chim'ie, vol. v. page 81. 

 " About the same time I discovered strontites to be a fusible sub- 

 stance ; for having obtained a portion of this earth pure, from a 

 specimen of thn carbonate of strontites of Argyleshire in Scotland, 

 I exposed it on charcoal to the flame of the compound blowpipe 

 after the manner described in my memoir above alluded to. It 

 became fused into a blackish semivitreous mass in shape some- 

 what semi-globular." 



Clark. " Here a difi'erent process is necessary ; the revival of 

 the metal is rendered more difficult, owing to the pulverulent state 



* The very jihrasc used by me in my original memoir. See quotation on 

 preceding page. 



of 



