108 Mr. J. Prideaux on Chemical Symbols and Notation. 



multiplicity of terms, &c. : the contracted does not apply; bui 

 both together will do very well. This simple case, then, amply 

 illustrates the need of varying the structure of our symbols 

 according to the occasion, when employed mathematically. 



The chief objection made to the mincralogical signs of Ber- 

 zelius is, that " the analysis itself is not recorded " by them. 

 But here would seem to be some misunderstanding. Their 

 difference from his chemical symbols is, that they do express 

 the result of analysis only, apart from atomic relations ; the let- 

 ters signifying merely the names ; and the figures giving the 

 relative quantities of the common ingredient, oxygen ; and, by 

 consequence, the constituents, from the known proportions 

 in which they contain it. Thus apophyllite is given by Ber- 

 ze\ms,{Noiiveau Sijsteme de Mineralogie, p. 225,) KSi^ + S CS ?'* 

 + 16 Aq: recording, that the oxygen in the lime is 8 times; 

 in the silica, 6 + 8 x 3 = 30 times ; and in the water, 16 times 

 that in the potash : whence the respective ingredients may be 



read off, on the scale of equivalents, K 5-95; Ca, 28*25; 



Si, 60; Aq, 18. And the cases quoted at p. 449 of Professor 

 Whewell's paper are rather equivalent than identical. 



Berzelius employs these signs in mineralogy, because " quant 

 aux formules chimiques, elles sont sujettes a changer d'apres 

 des changemens dans nos idees du nombre des atomes ele- 

 mentaires dont chaque substance est compose." Nmw. Syst. 1 90. 

 This is exemplified in the change of some of his own views 

 since that treatise was written. He would then have construed 



the above formula, chemically, thus : K Si * + 8 Ca Si' + 32 ^ y. 

 Now he regards potash and lime as each containing a single 



atom of oxygen ; and the chemical formula would be K Si" 



+ 8 CaSi + 16 A q; or without grouping K + 8Ca+ 10 Si 

 + 16 Aq; the proportions being still preserved. And hence 

 these signs seem peculiarly adapted to the purpose of minera- 

 logical record. 



The mincralogical notation proposed in the article quoted, 

 would require a local and chronological date to every re- 

 corded analysis, or would involve them in the hypothetical 

 changes of atomic chemistry. Had the above analysis of 

 apophyllite been so stated, the quantities of lime and potash 

 would have been reduced one half by the publication of 

 Berzelius's last atomic table; and the silica would have been 

 reduced two thirds by the formula being reprinted in En- 

 gland. 



With respect to the grouping in these formulae, the views 



of 



