4 1 2 On the Or'ighi of the Atomic Theory. 



oxysidphate, after the deposition of the oxide, remained as satu- 

 rated as the fresh-made sulphate itself previous to the change. 

 From the foregoing circumstance, it is probahle that a molecule 

 of sulphate of iron consists of an atom of jjcroxide and an atom 

 of acid, and that the proportions of its constituent elements are 

 three of oxvgen, one of iron, and one of sulphur ; and that a mole- 

 cule of oxysulphate consists of an atom of deutoxide of iron and 

 two atoms of sulphuric acid; consequently its constituent elements 

 are four particles of oxygen, one of iron, and two of sulphur. 

 The foregoing facts do not clash with Berzelius's hypothesis of 

 the proportions of oxide in the base and acid of saline substances. 

 This yellow oxide dissolves in sulphuric acid diluted with a small 

 quantity of water in a moderate heat, and no effervescence takcy 

 place; which proves that the yellow colour of the oxide of irou 

 is not occasioned by carbonic acid. This subject deserves more 

 attention and stricter investigation. The brown solution or oxy 

 sulphate of iron possesses some properties different from the sul- 

 phate, it is no longer crystallizable, and when evaporated to dry- 

 ness the mass is deliquescent. 



I observed in my Comparative View, that during the solution 

 of metals in nitrous acid they are first oxidized at the expense 

 of a portion of the acid itself, and that this oxide is held in so- 

 lution by nitrous acid, which is formed by a peculiar play of af- 

 finities during the chemical action of the ultimate particles of the 

 materials on each other, while at the same time nitrous gas is 

 evolved. The atomical demonstrations givep on this subject in 

 my Comparative Vicuj, page 138, or page 126 in my Atomic 

 Theory, are worthy the attention of chemical readers. 



I estimated this acid in metallic solutions to contain three of 

 oxygen, and the metallic base two. When a solution of potash 

 is poured into a solution of a metaUic nitrate, it takes the acid 

 with one-half the oxygen from the metal, and the nitrate of pot- 

 ash thus formed, consists of the straw-coloured nitrous acid and 

 the alkaline base. 



Other curious facts, which I noticed in my Comparative View, 

 on this subject, are worth relating here. " When iron is intro- 

 duced into nitric acid diluted with sixteen times its bulk of wa- 

 ter it is slowly dissolved, and azote instead of nitrous gas is dis- 

 engaged. Iron is dissolved in sulphurous acid, and there is no 

 hydrogen disengaged; if nitric acid be dropped in, the sul- 

 phurous acid is disengaged, and the nitric acid unites to the iron 

 without decomposition of any part of it, for no nitrous gas is 

 evolved*." These facts are accounted for on the atomic princi- 

 ple. The latter fact proves that the atom of nitric acid united 



* See pages 127, 128, and 129, of Atomic Theory. 



