438 Scientific Intelligence. 
With soluble silica (as prepared by igniting the silica from the decom 
position of an alkaline silicate), this reaction is very rapid, and even when 
pulverized quartz is boiled for several hours with carbonates of soda and 
magnesia, a large amount of magnesian silicate is formed. If we substi- 
tute proto-carbonate of iron and boil it with soluble silica and carbonate 
of soda, there is formed a hydrous silicate of the protoxyd permanent in 
It will be apparent that by virtue of the power of earthy carbonates to 
decompose an alkaline silicate, and that of the regenerated carbonate of 
soda to dissolve silica even in the form of quartz, a small amount of alkali 
may effect the combination of a great quantity of silica with earthy bases. 
Suppose a solution of alkaline silicate, which will never be wanting 
among sediments where feldspar exists, to be diffused through a mixture 
of siliceous matter and earthy carbonate, and we have with a tempera- 
ture of 212° F. and perhaps less, all the conditions necessary for the con- 
version of the sedimentary mass into pyroxenite, diallage, serpentine, 
rhodonite, all which constitute beds in our metamorphic strata. Add to 
the above the presence of aluminous matter and you have the elements 
of chlorite, garnet and epidote. We have here the explanation of the 
metamorphism of the Silurian strata of the Green Mountain range, 
I believe of rock metamorphism in general. 
ave just communicated a detailed account of my investigations to 
the Royal Society of London, and will soon furnish you with farther ob- 
servations. 
III. BOTANY. 
be eagerly welcomed and much sought after, alike by students just enter- 
ing upon a charming branch of botany, and by our more advanced eulti- 
vators of Bryology. For the latter, the simple announcement of the pub- 
lication of this collection is sufficient. For the benefit of those not 80 
well informed upon the subject, we may state, that the value and import- 
ce of these sets of specimens are greatly enhanced by the fact that 
they have been all studied and named by the author of the Muscology 
of the United States (east of the Mississippi), comprised in Gray's 
Manual of Botany (the only book in which our Mosses are described at 
all),—aided by his excellent coadjutor, M. ne ae Oe nieny 
accordingly specimens of the very things described in that work; pec 
that the sets are so complete that they comprise almost all the _— 
Musci (or true Mosses) contained in the Manual. On this account, %® 
well as on account of the care with which the specimens have bee 
- these published sets are unsu: , if not w ange eet? 
vious muscological collection ever issued. The numbers on printed 
* 
eee pe, 
