THE 



PHILOSOPHICAL MAGAZINE 

 AND JOURNAL. 



30 th NOVEMBER 1824. 



L V. Contributions to our Knowledge of Chemical Bodies. 

 By Mr. W. Herapath*. 



No. 1. On the Combinations of Oxygen. 



A DESIRE to know the state in which oxygen exists after 

 "^*- combination, induced me in 1821 to commence a set of 

 experiments upon the metallic oxides ; in the course of which, 

 many new facts have presented themselves, which I conceive 

 are worth recording ; and under this impression I shall venture 

 to make them public; although from the tedious manipula- 

 tions required to purify the different substances, the necessity 

 of taking their density at one particular temperature, and 

 the short time I can devote to such pursuits, I find it im- 

 possible to present a complete series of the metals and their 

 oxides, as was my original intention. In following up my 

 ideas on those bodies, I had expected to derive some informa- 

 tion from the labours of others ; but unfortunately, I found 

 that the oxides had been scarcely at all operated on, as far as 

 regarded their densities ; — at least I am not aware that any ta- 

 ble of their densities was ever published : and although it had 

 been considered of sufficient importance to ascertain the den- 

 sity of the various metals ; yet, from the inattention of the ex- 

 perimenters to their purity, — to the propriety of their being 

 reduced without alkaline fluxes, to their being allowed to cool 

 slowly in the crucible in which they were melted, and to the 

 neglect of registering the temperature at which the specific 

 gravities were taken, — there is so much confusion, that it is with 

 great difficulty I can select enough to form a table. I have 

 done so here: but as I consider it absolutely necessary that all 

 the experiments should be repeated ; if this notice fails to call 

 the attention of chemists to this department of science, I shall 

 extend my task to it : but from the magnitude of the under- 



* Read before the Society of Inquirers of Bristol, September 20, 1824. 

 Vol. 64. No. 319. Nov. 1 824-. Ss takinj-- 



