332 NATURE AND DECOMPOSITION OF THE FIXED ALKALIS. 



An instinmcnt In themselves they will undoubtedly prove powerful 



of decomposi- , . • cc -j. r 



jion. agents tor analysis ; and having an atnnity for oxigen 



stronger than any other knovv^n substances, they may 

 possibly supersede the application of electricity to some of 

 the undecompounded bodies. 

 Base of potash The bases of potash I find oxidates in carbonic acid and 

 ciirb'onic"acid. decomposes it, and produces charcoal when heated in con- 

 tact with carbonate of lime. It likewise oxidates in mu- 

 riatic acid ; but I have had no opportunity of making the 

 experiment with sufficient precision to ascertain the results. 

 Geology. In sciences kindred to chemistry, the knowledge of the 



nature of the alkalis, and the analogies arising in con- 

 sequence, will open many new views ; they may lead to the 

 solution of many problems in geology, and show, that 

 agents may have operated in the formation of rocks and 

 earths, which have not hitherto been suspected to exist. 



It would be easy to pursue the speculative part of this 

 inquiry to a great extent, but I shall refrain from so oc- 

 cupying the time of the Society, as the tenour of my ob- 

 ject in this lecture has not been to state hypotheses, but to 

 bring forward a new series of facts. 



II. 



On the Composition of the Compound Sulphur et from Iluel 

 Boys, and an Account of its Crystals. By James 



Compound sul- IT is but very lately, that I have seen the Philosophical 



phuret from Transactions for 1804, and become acquainted with the two 

 HuelBoys, ' ^ 



papers on the compound sulphuret of lead, antunony, and 



copper contained in the first part of it + ; which circum- 

 stance has prevented my offering sooner a few observations 

 on Mr. Hatchett's experiments, which I deem essential 

 towards this substance being rightly considered, and indeed 

 the principles of which extend to other chemical com- 

 pounds ; and also giving an account of this compound sul* 



* Philos. Trans, for 1807, Part 1, p. 55. 

 t See Journal, vol. IX, p. 14. 



phuretj 



