46 T. S. Hunt on the Criticisms of Prof: Dana. 
which the theory of metamorphism by alteration has been 
built, are, for the most part, examples of association and en- 
velopment, and the result of a contemporaneous and original 
erystallization,—is identical with the view suggested by Scheerer 
in 1846, and generalized by myself, when, in 1853, I sought to 
explain the phenomena in question by the association and crys- 
tallizing together of homologous and isomorphous species.” 
To Delesse therefore belongs the merit not of having suggested 
the notion of envelopment in this connection, but of ha aving 
pointed out the bearing of the pbhocate tie ts 6 senishiereaackan: 
and amorphous species on the question befo 
Prof. Dana moreover asserts that while Silewice is the onl 
one who maintains similar views to myself, I, in common wit 
all other chemists, reject the chemical speculations which lie at 
the base of his views. On the contrary, unlike most chemists, 
who have failed to see the great principle which underlies 
Scheerer’s doctrine of po re ae ism, I have main- 
Jo 
iffer by nM, nH,O,, may cag those differing by 
»C,), have fa of homo ogy, and moreover be isomor- 
phous. The existence of these same — was further 
maintained and exemplified in sel tomic Volumes, 
read by me before she French Aca ct of Sciences and ub- 
stone to dolomite, and im doumaia to serpentine ; or more 
directly from granite, granulite or diorite to serpentine at once, 
without passing through the intermediate stages of limestone 
and dolomite ;’—“ part of which transformations,” says Prof. 
Dana, ~ phe one, had never conceived ; and Rose, Haidinger, 
Rammelsberg, and probably Blum, and the | many others,’ 
” h 
pret st udiate them asstrongly as myself.” The ‘ many other ers,’ 
as he a ee remarks, are “ other writers on pseudomorphism,” 
among whom it would be unjust not to name their progenitor, 
Breithaupt, von Rath and Miller, at the same time with Volger 
and Bischof. According to Prof. Dana, I “add to the misrep- 
