370 
INDEX. 
T. 
Telescope. Constructed with a fluid concave lens of 7.8 inches aperture, described, 36. 
Thames. On the spontaneous purification of its water, 287 et seq. 
Torpedo. Experiments on the torpedo, 15 et seq. 
Torsion. Table of the modulus of torsion of various woods, 129, 130. 
Table of the modulus of toi’sion of various metals, 131. 
Turner (Dr. Edward). On the composition of chloride of barium, 291 et seq. 
V. 
Vacuum. On the reduction to a vacuum of the vibrations of pendulums, 207 & 331. 
W. 
Warren (Rev. John). Consideration of the objections against the geometrical represen- 
tation of the square roots of negative quantities, 241 et seq. 
On the geometrical representation of the powers of quantities 
whose indices involve the square roots of negative quantities, 339 et seq. 
Water of the Mediterranean. Salter at considerable depths than that of the ocean generally, 30. 
Water of the Thames. Its spontaneous purification, 287 et seq. 
Wollaston (William Hyde, M.D.). On a method of rendering platina malleable, 
1 et seq. 
Description of a microscopic doublet, 9 et seq. 
On a method of comparing the light of the Sun 
with that of the fixed Stars, 19 et seq. 
On the water of the Mediterranean, 29 et seq. 
On a differential barometer, 133 et seq. 
Y 
Yelloly, (John, M.D.). Remarks on the tendency to calculous diseases; with obser- 
vations on the nature of urinary concretions, 55 et seq. 
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MDCCCXXIX. 
