254 Chemical formulas of the Silicates. 
proportions appear to be at times indefinite. To clear away also 
these fractions arising from isomorphous substitutions would 
make formulas of great complexity, and in some cases almost 
as many different ones for a Species as there may be localities if 
not analyses. And besides, the several formulas under a single 
Species thus obtained would differ vastly in the number of atoms 
which they would indicate to be present in the different repre 
sentatives of one and the same species, so that nature and chem™- 
ce. 
t, 
included), the species probably differ by some simple ratio o 
has bess already seclsingd But until the exact 
than to perform the multiplication with each member of it. 
It may de objected to the following formulas that the bFe, 
