448 Rev. W, Whewell on the Employment 



As examples of the use of this notation, I will take the 

 minerals in which lead is an ingredient. 



Carbonate of lead . P b + 2 cf 



Sulphate . . . . P b + 2 *' 



Arsenio-phosphate . P 6 + p', ar' 



Molybdate . . . P b + 2 mo' 



Tungstate . . . P 6 + 2 tu' 



Chromate . . . P b + cr' 



Murio-carbonate . Pb + 2cf + Pb + 2 cl (Berzelius) 



Sulphate-carbonate . P&-f-2c' + P6 + 2s' 



Sulphato-tricarbonate 



Sulphuret . . . . 



The preceding notation is intended principally for the pur- 

 poses of mineralogy ; in the calculations of chemistry it would 

 be necessary to have some additional contrivances. Thus, it 

 would be proper, as I have already observed, to indicate the 

 mode in which both the oxides and the acids are formed from 

 their bases, by the addition of definite portions of oxygen. 

 For this purpose let o represent an atom of oxygen ; also 

 let h be an atom of hydrogen ; and we shall have the fol- 

 lowing symbols : 



fe + o = protoxide of iron (Fe),fe -f--f o = peroxide (Fes.) 

 mn + o = protoxide of manganese (Mw), mn + -|o = deut- 



oxide, (M?w) run -\- 20 =: peroxide (Mwi). 



mn + 3 o =s manganesious acid, mn + 4 o = man gauesic. 

 ar-\- f o = arsenious acid, ar + f o = arsenic acid (a/) 

 s + h = sulphuretted hydrogen, s -f- 2 o = sulphurous acid, 5 + 



3 o = sulphuric (s / ). 

 fl + h = hydrofluoric acid (fl 1 ) cl + h = hydrochloric acid 



It may occur as an objection to this system, that we have thus 

 two ways of representing the same element, as/e + o and F e 

 for protoxide of iron, s + 3 o and s f for sulphuric acid, fl + h 

 and fl for hydrofluoric acid. But it is to be observed, that 

 the former symbol in each of these cases is the regular and 

 systematic one, and the latter is merely an abbreviation, which 

 may be employed for the sake of convenience, and which, I 

 believe, in the cases of minerals it will generally be most simple 

 to use. We may make such abbreviations for all the oxides 



