of Notation in Chemistry* 445 



-fN + 2? = 3(2S + A 



+ C4-3?=: 3(S+A) 



(8) = 6S-f3A+N + 2g=3(S + A)+( 



The last column, containing the grouping of the ingredients, 

 is for the most part according to the views of Berzelius. 



If we now wish to compare the quantities of the ingredients 

 in any case, we have only to introduce the atomic weights. 

 Thus, for Heulandite, we have 



15S + 4A+C +6q 

 = 240 + 72 + 28 + 54 = 394. 



There is no necessity to reduce these quantities of the ingre- 

 dients to the supposition of 100 for the total, nor to do so with 

 any given analysis ; since the comparison of the analysis with 

 the formula may be made with greater brevity, by avoiding such 

 an intermediate step, and by trying directly the proportionality 

 of the numbers in the experiment with those in the formula. 



In order to compare the constitution of different species, as 

 for instance those above mentioned, it would be convenient to 

 reduce the most prominent term, which appears here to be one 

 with S, to an identity in all, by multiplication or division ; this 

 process would give the following results : 



S(16)A(18) C(28) g(9) Total. 



2 x(2) = 30S+8A+2C + 12g 480 144 56 108 788 



30S + 7iA + 2C + 15<7 480 135 70 135 820 



30S+10A + 2B+15g 480 180 (195,B) 135 990 



30S-H2A + 3 C+18<? 480 216 84 162 942 



30S + lliA+3fN + 7^ 480 202 (120,N) 67* 870 



5 X(7)=30S + 15A + 5 C+15g 480 270 140 135 1025 



5 X(8) = 30S-H5A+5N+10g 480 270 160 90 1000 



As (1) contains the ingredients with somewhat different 

 relations, the results are not here given for that species. 



In some cases it is found that different ingredients are 

 isomorphous, or may replace each other without altering the 

 form or species of the mineral. Thus we have Chabasite of 

 the formula 8S + 3A+ C + 6 y ; and also of the formulae 

 8S+3A + K + 6^,and8S + 3A + N + 6 </ ; and a mix- 

 ture of the two latter kinds, including both K and N. In such 

 cases a part of the term corresponding to K appears to be potassa, 



