INDEX. 
Sympathy of corresponding’ points of eyes shewn to arise from struc- 
ture, not from habit, 226. 
Systems , binary, of stars, Part iii. 1. 
T 
Temper of steel, its influence on the magnetic power communi- 
cated by percussion, 211 — elasticity of steel not dependent on it, 
356. 
Temperature at which various gasses combine directly with oxygen, 
277— ditto, under the influence of spungy platina, 278. 
Testaceous animals, observations on the relative periods of their 
creation, 413 ; vide skells. 
Testes of birds, enlargement of, the cause of migration, 20 — size of, 
in different birds, 40. 
Thalami nervorum op ticorum, nature of the incorporation of nerves 
in, examined, 223. 
Thaw, its approach indicated by the return of fieldfares, 34. 
Tiarks, Dr. J. L. his chronometrical determination of the longitudes 
of Madeira and Falmouth, 360-371. 
Tin, one 300th part soldered on copper prevents the action of sea 
water — its electro-mechanical effect in alloy with mercury, 183 
- — inferior to zinc, 183. 
Trachelipoda, carnivorous, found in oolite, 414 — epoch of their 
first appearance in strata, ib. 
Tredgold, T. Esq. civil engineer. His experiments on the strength 
and elasticity of hard and soft steel, 354. 
Trent, anomalies observed on board of, in variation of the compass, 
330 — produced by iron stowed in her, 331. 
Trigonometrical measurement of a height in Spitzbergen, 290. 
— — Survey, error of 4" in longitude of Pendennis 
Castle, 361. 
Troughton, his micrometer, iii. 9 — brass-work of Mr. South’s 
equatorial, made by him, iii. 11 — his observations of double stars, 
Van Beek* experiments on velocity of sound made in Holland by, 
424. 
Variations, annual, of stars, table of, 83. 
Velocity of sound , 424 ; vide sound. 
Vision, diseased, inference respecting the optic nerves drawn from 
some cases of, 222, etseq. 
