t 899 ] 
Tables. 
Refults of experiments on the expaniion of air of the denfity of the common atmos- 
phere, p. 703. 
Expanfions for intermediate temperatures, p. 704. 
Refults of experiments cn the expanfion of air, artificially moiilened, by the admifiion 
of fteam, and fometimes water, into the bulb of the manometer, p. 705. 
Heights -determined geometrically, p. 717, 78 r. 
The equation depending on the temperature of the column of air, its elevation 
above the fea, as denoted by the mean height of mercury in the inferior and fu- 
perior barometers, p. 771. 
Computations of barometrical obfervations made on heights in and near London, 
P- 773 - 
Computations of barometrical obfervations made on heights near Tay bridge, near 
Perthlhire, and of thofe near Lanark, p. 77^. 
Computations of barometrical obfervations made on heights near Edinburgh, p. 777. 
Computations of barometrical obfervations made on heights near Linhoufe; and of 
thofe near Carnarvon in North Wales, p. 779. 
Computations of part of Mr. De Luc’s barometrical obfervations, anfvvering to the 
coldell and hotted: temperatures of the air, p.781 — 784. 
Computations of barometrical obfervations made on heights that have not been de- 
termined geometrically, p. 785. 
Computations of Mr. Bouguer’s barometrical obfervations in Peru, p. 787. 
For adjufting the boiling point of thermometers, p. 8^4, 
For adj idling the freezing point of thermometers, p. 846. 
Vails. Remarkable cow- tails produced in the kingdom of Thibet, p. 484. To what 
ufe they are applied, p. 484, 485. The beak defcribed, p. 484. 
Tar and lamp-black, or lamp-black and oil, have preferved the parts of mails of fhips 
which were covered with it from injury by lightning, p. 85, 86. A curious in- 
ftance of this kind, p. 86 — 89. 
Tarpeian Rock at Rome, its height determined by the barometer, p. 584. 
Tartars, heathen, who the great objed of their adoration, p. 474—476. 
Tay bridge , in Perthlhire, computations of barometrical obfervations made on heights 
near there, p. 775. 
Tayjhoo Lama of the kingdom of Thibet, fome account of him, p. 468. 475. 479 481. 
Tranflation of his letter to the governor of Bengal, foliciting a peace, p. 489 402. 
Tele/copes Directions for making the bek compofition for the metals of receding tele- 
fcopes ; with a defcription of the procefs for grinding, policing, and giving the 
great fpeculum the true parabolic curve, p. 296. Enquiry concerning the compo- 
fition for the fpecula of reflecting teiefcopes, p. 297 — 301. Hoiv to make the bell 
metal for this purpofe, p. 302,503. Four tools only neceffary for grinding and 
polifhing it, p. 304. Of rough grinding the fpeculum, p. 304 — 306. The manner 
5 T 2 of 
