co L 
Cog-wheels, on the forms of, E. W. 
Blake, vii, 86.£ 
Cohesion, experiments with soap 
bubbles on attraction of, J. Henry, 
xlviii, 216. 
Coins, remarks on, and descriptions 
of some ancient, xxvii, 74. 
and medals, character and 
composition of, J. W. Draper, 
xxix, 157. 
Coir fibre, used for ropes, xxi, 33. 
Coke, natural, of Virginia, W. B. 
Rogers, xlii, 175. 
Cold, effects of, ii, 177. 
, artificial, produced by mixed 
metals, xii, 171. 
‘ , a freezing mixture for, 
xii, 195. 
, extraordinary seasons of, JY. 
Webster, xxviil, 183. 
at New Haven in 1766, 1767, 
xxvill, 183. 
at Hartford in 1780, xxviii, 
186. 
, extreme, at Plattsburgh, N. 
Y., 11, 366; x1, 195. 
in Maine, 1817, mercury fro- 
zen by, xxxi, 161. 
on Lake Superior, ix, 395. 
of the winter of 1825-6, x, 
399. 
of January, 1835, xxviii, 177. 
winter of 1837, 1838, in Eng- 
land, J. Lindley, xxxix, 18. 
Colden, Cadwallader, correspon- 
dence with Gronovius, Linneus, 
&c., xliv, 85. 
Collapse of a reservoir, R. Hare, 
xxxiil, 242.f 
Collins, Z., herbarium of, xxili, 398. 
Collinson, P.,letters from, to C. Col- 
den, xliv, 112. 
Colombia, features of, R. Wright, 
XXXVIl, 2. 
, river Orinoco, rise of, xxxvii,2. 
, climate and seasons of, 
RORKVIIN IS 
» mists above 12000 feet, 
XXXVIl, 3. 
, llamas and horses of, xxxvil, 
14. 
54 
Cc OoL 
Colombia, vegetation and produc- 
tions of, xxxvii, 15. 
Colophane, a tree affording an aro- 
matic oil, ix, 386. 
Colophonite, of Willsboro’, N. Y., 
H. Seybert, v, 117. 
Color of air and deep waters, and 
some other analogous fugitive 
colors, Count Xavier de Maistre, 
xxvi, 65.f 
of opaline glass, xxvi, 66. 
of leaves in autumn, Macaire 
Prinsep’s views respecting, xvi, 
215. 
of the Raphael Tapestries, ef- 
fect of light and air in restoring, 
xxxvil, 244. 
of the sea, due in part to io- 
dine and bromine, xvii, 170. 
of wood of certain trees, 
change of, xviil, 404. 
, blue, from buck-wheat, xxii, 
384, 
, carmine, produced on ivory 
by red lead on the under side, 
KOR nd Ae : 
, increase of, when objects are 
seen with the head inverted, D. 
Brewster, x|, 343. 
, inability to distinguish, xl, 54. 
Coloring matter for dyeing, experi- 
ments on, M. Persoz, xxiv, 380. 
of the Lichen rocella, 
xviil, 151. 
materials for confectioners, 
xxil, 381. 
Columbic acid, A.A. Hayes,xlvi,166. 
Columbite, investigations on, Rose, 
xlix, 228. 
from New Hampshire, large 
crystal of, C. U. Shepard, xvii, 
357.f 
, Stanniferous, discovered in 
Massachusetts by C. U. Shepard, 
xvi, 220.f 
, a large crystal of, from 
Middletown, Conn., J. Johnston, 
xxx, 387.f 
, localities of, in Connecticut, 
iv, 52; vi, 236; xxx, 387 ; Xxxill, 
162. 
