62 Royal Society of Edwliir^h. 



doctrine with regard to oxynuiriatic acid, that it is a weaker acid 

 tlian the imiriatic, thoii^^h it has received an additional portion 

 of oxygen. It is so precisely as sulpliurous acid is weaker than 

 sulphuric. The proper points of resemhlance are the sulpliu- 

 rous acid with the osymuriatic, and the sulphuric witii the niu- 

 riiitic. It was shown that oxyniuriatic acid has a stricter ana- 

 logy to sulphurous acid than to any other body ; and that any 

 deviation from this analogy arises from the large projjortion of 

 oxygen, which the former contains. 



The relations of iodine, the analogy of which in some respects 

 to those of chlorine has chiefly given predominance to the new 

 doctrine, with regard to tlie latter accords perfectly with these 

 views The nature of the compounds of inflanunable iiodies with 

 chlorine accords also better with them than with eitlier of the 

 other doctrines. And they serve to explain a numlier of other 

 facts connected with the action of acids and their combinations. 

 They afford for example a solution of the difficulty which t^ave 

 rise to the investigation — that of the production of water in the 

 action of metals on muriatic acid gas. 



Dr. .\I. extended the same view to the constitution of the al- 

 kalis. A'kalinity is as well as acidity a result of the agency of 

 oxygen, — the fixed alkalis, the earths, and metallic oxides, all of 

 whicli contain oxygen as a common element, forming a series in 

 which there is no well defined line of sepiration. Ammonia 

 stands insulated ; it contains no oxygen, yet its alkaline projjer- 

 ties are energetic, an anomaly wiiich has led generallv to the be- 

 lief thai oxygen must exist in one or other of its constituent 

 principles. It may be explained, however, on a verv different 

 ])rinciple. As hydrogen like oxygen communicates aciditv, so it 

 may like oxygen give rise to alkalinity. Ammonia tlicrefore will 

 be a compound, of wiiich nitrogen is the base, deriving its alka- 

 line quality from hydrogen; and hence stands in the same rela- 

 tion to the other alkalis that sulpiiuretted hvdrogen does to the 

 acids. If the claim or the newly-discovered principle in opium 

 to the rank of an alkali be established, it uiav stand in the same 

 relation to the others that prnssic acid or some of the vegetal)le 

 acids do to the acids. 



riie fixed alkalies, barytes,strontites, and lime have been sup- 

 posed to contain combined water essential to them in their insu- 

 lated form. It is probable that the elements of water rather exist 

 in direct combination with their metallic l)ase : that potash, for 

 example, is a ternary compomid of potassium, oxvgen, and hv- 

 drogen ; and thus the entire class will exhibit the same relatioiis 

 as the class of acids, some being compounds of a base with oxv- 

 gen, ammonia a compound of a base with hydrogen, and potash, 

 sodi, &c. compounds of a ba'^e with oxygen and hydrogen ; and 



these 



