54 COWARD & HARDEN, Dalton's Lecture Sheets. 



Sheet 16. 



Formulae and names for the following compounds 

 of phosphorus : — 



PO Phosphorous acid. 



P 2 Subphosphorous acid. 



P0 2 Phosphoric acid. 



PH Phosphuretted hydrogen. 



These are later than 1810, for in that year phosphorous 

 acid was represented as P 2 2 (" New System," I., i., plate 

 5), and subphosphorous acid was unknown. 



Sheet 17. 



Formulae, only, for the sulphate, carbonate and oxide 

 of barium. 



Sheet 18. 



Formulae, only, for the oxides and sulphides of gold, 

 mercury, iron, lead and arsenic, described in " New 

 System," II. 



Sheet 19. 



Formulae, only, for some compounds formed of two 

 or more of the elements lead, arsenic, iron, sulphur, 

 oxygen and hydrogen. 



Sheet 20. 



Formulae for prussic acid [HC 2 N 2 ], cyanogen 

 [CN], ferrous oxide [FeO] and potash [KO]. 



Sheet 21. 



Formula, with inscription " Acetic acid wt. 26 



[? 25]." 



Acetic acid is represented by symbols equivalent to 

 C 2 H 2 2 . 



