Analogies observed in Chemical Unions. 365 



to have the hydro-base C^" H^" as its foundation. "We have 

 the hydrate of the oxide of the series in potato-oil C^° H^^ 

 + HO, corresponding to alcohol and pyroxylic spirit ; and va- 

 rious saline ethers, although its simple ether has not yet been 

 formed. 



Phosphuretted-hydrogen H^ P- may be regarded as a mem- 

 ber of the series of hydi'ogen bases. It unites directly with 

 hydracids to form crystallized compounds. From the inferior 

 tendencies, however, of hydro-bases to unite with oxyacids, it 

 has not much affinity for the latter ; but the disposition to fol- 

 low out the analogy is manifest, for, by the experiments of 

 Buff and Rose, it is absorbed by oil of vitriol, and the solution 

 remains for a certain time undecoraposed ; during the tempo- 

 rary union passing, perhaps, into the state of an oxybase in 

 the usual way. Ammonia expels it as one more powerful base 

 does another. 



Such are the hydro-bases having simple radicles, so far as 

 at present known ; but there appears to be a farther numerous 

 series of allied combinations, of more complex constitution, 

 and belonging properly to organic chemistry; and into the 

 constitution of all of these hydrogen enters along with carbon, 

 nitrogen, and usually oxygen. The several vegetable alkaloids 

 are the principal instances of this kind. These follow exactly 

 the analogy of ammonia in their combinations. They are, in their 

 separate state, strongly alkaline. They unite directly with hy- 

 di'acids to form salts. In combining with oxyacids, they change 

 their type, passing into the state of oxybases through the in- 

 tervention of the elements of water. We have yet, however, 

 no evidence of the separate existence of a radicle analogous to 

 ammonium. I did not find any such evidence when a globule 

 of mercury Avas submitted to voltaic action in a solution of 

 muriate of morphia, or when it had been previously alloyed 

 with sodium ; neither does it seem to be necessary, as will be 

 presently noticed, that the pure alkaloids themselves should be 

 held actually to contain radicles, as such, united to hydrogen. 



Next to the vegetable alkaloids, the artificial bases, such as 

 melamine C' N'' H", and ammcline C' 0- N^ H^ &c., may be 

 noticed as coming under the same general laws. 



Urea C^ 0^ N^ H^ may be classed in the same list, for, by 



