286 Mr. VV. Herapalli on Ihe 



separate; and that this property varies accortling to the nature 

 of each. Those of tlie metals which would best produce the one 

 effect would not produce the other, or but in a less degree. 



We shall abstain from offering some iurther conjectures 

 to which these singular pha^nomena give rise in our nunds, 

 luitil we sliall have terminated the experiments which we have 

 imtiertaken in order to verify them. 



LIX. On Dcebaeinei' s new Experiment. By William 

 Herapath, Esq.* 



October 20, 1823. 



'^pHE philosophical publications and newspapers have lately 

 -*■ announced an experiment by Da4)ereiner with hydrogen 

 gas and platinum in a finely divided state. Those announce- 

 ments were either not accompanied by a description, or by one 

 evidently so inaccurate as to cause chemists in general to treat 

 it as an "attempt at the marvellous : the impression made upon 

 my mind was, that Doebereiner himself had not discovered the 

 changes which were effected ; and I regret that Mr. Fsiraday 

 of die Royal Institution did not prosecute his inquiries further 

 than verifying the one experiment. 



I therefore made a series of experiments, to make myself ac- 

 quainted with the phasnomena ; and, as they throw some light 

 upon the subject, I beg to offer them to this Society for its in- 

 formation : but I shall first premise, that it was before known 

 that oxygen, iodine, chlorine, and sulphur, would, in some 

 cases, where they rapitlly united, give out caloric and light suf- 

 ficient to produce those effects which have been termed igni- 

 tion and combustion : but no such knowledge had been ac- 

 (juired of hydrogen. Consequently, as this experiment of Doe- 

 bereiner's appeared to prove that pure hydrogen also had that 

 property, it was of importance that it should be minutely in- 

 vestigated. 



Exj). 1. A stream of hydrogen as generated from zinc, &c., 

 and therefore mixed with connnon air, was passed ujtou 5gr. 

 of the spongy mass (as obtained by heating to redness the am- 

 monia-muriate of platinum) in a thin glass capsule; the metal 

 became red hot quite close to the orifice from which the 

 stream issued ; but as the gas became purer from the smaller 

 proportion of air, I found it necessary to remove the metal to 

 a little distance ; the great heat set fire to the hydrogen ; I 

 extinguished it, and occasionally removed the platinum so as 

 to prevent the recurrence of flame. After the cxpeiiment had 

 continued half an hour, the metal was examined ; there was no 



* Read before the Bristol Piiilosophical Society of Inquirers; and com- 

 municated by the iVulhor. 



change 



