370 Domestic Intelligence. 
the root of a convolvulus or any other plant. ‘The tuckahoe 
occurs from one to three feet under the surface of the earth. 
Its form is for the most part globular, and it is found from 
the size of an acorn to the bigness of a man’s head. Dr. 
T. has ascertained that the tuckahoe. belongs to the genus 
sclerotium of Tode and Person, and that itis an undescribed 
species of that genus which he-calls S. giganteum. Dr. 
Macbride supposed that the substance of the sclerotium con- 
sisted of gluten in a peculiar state. Dr. 'T. in an elaborate 
analysis of this fungus, has proved that no gluten enters into 
its composition, but that it consists almost entirely of a pe- 
culiar vegetable principle which he calls sclerotn. This 
supseuiee! is very soluble in even weak caustic alkalies, and 
the solution gelatinizes by acids and most neutral salts. 
Dr. Torrey read an account of a new mineral from Schoo- 
ley’s mountain, New-Jersey. It somewhat resembles 
graphite, but is much heavier and possesses very different 
characters. According to Dr. 'T’s analysis it consists of iron 
in a metallic state, and graphite, i in the proportion of 54.25 
of the former, and 11.50 of the latter. He proposes for it 
the name of siderographite. : 
1819.—Mr. I. P.’ Brace, a corresponding member of the 
Society, communicated a memoir on the geology and min- 
eralogy of Litchfield in Connecticut, which he illustrated 
with a handsome suite of specimens. Litchfield is entirely 
primitive, and the basis rock of all the hills is gnezss, though 
gramte is occasionally found alternating with it. The rocks 
lying on this are porphyriiic granite, mica slate, siente, 
primitive greenstone, steatite and limestone. -Mount Pros- 
per, near the west end of the town, is entirely composed of 
porphyritic granite. Mount Tom, south west of the town, 
appears to be composed of rocks of sienite heaped together 
on a base of this granite. Among the minerals sent by Mr. 
Brace, were large and beautiful crystals of cyanzte associa- 
ted with tale and mica slate, staurotide with garnets, in mica 
slate, chalcedony, blue feldspar, and beryls in large erystals 
in granite. 
A memoir was read by the president, Dr. Mitchill, on an 
interesting species of fish, viz: Gobiomones grandicauda, ° 
Bodianus triacanthus, Esox tirrhatus, Diodon verrucosus; 
