202 Prof. J. P. Cooke on the Variation of Constitution ina 
cases; and I found that with the alloy containing 48 per cent of 
large number of specimens, and discussing their various a lgres 
there has been a substitution of isomorphous elements ; i al 
tl 
iform & 
With one other consideration I will close this paper. es 
priaciple which has been here discussed must modify materia) 
* See Table in the memoir before cited. 
ee ee Se ee 
