408 Researches on 



tion, and an equilibrium of attraction, may give to a com- 

 pound, containing several constituents, that refractory cha- 

 racter, which is generally attributed to unity of constitution, 

 or to the homogeneous nature of its parts? 



Besides the compound of the phosphoric sublimate and 

 ammonia, and the other analogous compounds which have 

 been referred to, it is probable that other compounds of like 

 nature may be formed of the oxides, alkalies, and earths, 

 with the oxymuriatic combinations, or of the oxymuriatic 

 compounds with each other; and should this be the case, 

 the more refined analogies of chemical philosophy will be 

 extended by these new, and, as it would seem at first view, 

 contradictory facts. For if, as 1 have siid, oxymuriatic 

 acid gas be referred to the same class of bodies as oxygen 

 gas, then, as oxygen, is not an acid, but forms acids by 

 combining with certain inflammable bodies, so oxymuriatic 

 acid, by uniting to similar substances, may be conceived to 

 form either acids, which is the case when it combines with 

 hydrogen, or compounds like acids or oxides, capable of 

 forming neutral combinations, as in the instances of the 

 oxymuriales of phosphorus and tin. 



Like oxygen, oxymuriatic acid is attracted by the positive 

 surface in Voltaic combinations ; and on the hypothesis of 

 the connexion of chemical attraction with electrical powers, 

 •all its energies of combination correspond with those of a 

 body supposed to be negative in a high degree. 



And in most of its compounds, except those containing 

 the alkaline metals, which may be conceived in the highest 

 degree positive, and the metals with which it forms inso- 

 luble compounds, it seems still to retain its negative char 

 racter. 



I shall occupy the time of the Society for a few minutes 

 longer only, for the purpose of detailing a few observations 

 connected with the Bakerian lectures, delivered in 'the two 

 last years; particularly those parts of them relating to sul- 

 phur and phosphorus, which new and more minute inquiries 

 have enabled me to correct or extend. 



J have already mentioned that there are considerable dif- 

 ferences in the results of experiments, made on the action 

 of potassium, on sulphur and phosphorus, and their com- 

 binations with hydrogen, according to different circumstances 

 of the process. 1 shall now refer to such of these circum- 

 stances as I have been able fully to investigate. 



The able researches of Dr. Thomson have shown that 

 sulphur, in its usual state, contains small quantities of acid 

 matter; and though, in my first experiments, I conceived 



* that 



