INDEX. 
Ritchie, William. A. M., on a new form of the differential ther- 
mometer, with some of its applications, p. 129. 
S 
observations on, p. 368. 
of a magnetized needle 
Serpentiform Fishes , on a newly discovered genus of, p. 49. 
Silver , bichromate of, p. 222. 
Simple alimentary substances , on the ultimate composition of, with 
some preliminary remarks on the analysis of organized bodies in 
general, p. 355. 
Simple elements, on the expediency of assigning specific names to 
such as represent definite physical properties, p. 25. 
Soda , potash-chromate of, p. 223. 
Solar tables, remarks on a correction of, required by Mr. South’s 
observations, p. 65. 
Spherical aberration and dispersion, experimental examination of 
the limits within which an error in them may take place, with- 
out producing a sensible defect in the object-glass, p. 254. 
Steam Engine, observations on, p, 32. 
Submaxillary odoriferous gland in the genus Crocodilus, on the 
structure of, p. 132. 
Sugars, analyses of, p. 369. 
Sugar of milk, composition of, p. 383. 
— — from the cane, composition of, p. 371. 
of honey, composition of, p. 872. 
Sugars, table of the composition of several, p. 373. 
T 
Table, showing the aberration of a lens for parallel rays to four 
indices, p. 249. 
Thomson, Thomas, M. D. on some of the compounds of chromium, 
p. 159. 
Transit-instruments, on the derangement of, by the effects of tem- 
perature, p. 144. 
Transparent screens of extreme tenuity, on their permeability by 
radiant heat, p. 139. 
by an iron shell, on. 
Saccharine principle, 
Secondary deflections 
p. 276. 
