E 433 ] 
clafles of hygrofcopes, p. 29. Obfervations on the fcale of the hygrometer between 
the two fixed points, p. 24. Experiments on the comparative changes of weight and 
dimenfiors of fome hygrofcopic fubftances, p. 27. Experiments on the recoil of 
hygrofcopic threads, p. 39. Hygrometers varioufly affeded by fcattered atmofpheres 
of extreme moifture, p. 401. Steadinefs the firft requilite for an hygrometer, p. 
418. Defcription of the whalebone hygrometer, p.419. 
Hygrometry , obfervations on, p. 1. 389. 
I. 
James’s powders, experiments and obfervations to invefligate the compofition of, p. 317* 
Its nature hitherto unknown to the public, ibid. Senfibie properties of the powder* 
ibid. Smooth to the feel, with fome rather rough particles, ibid. Gritty in the 
mouth, p.318. Perfedly inodorous, ibid. Gn the fpecific gravity of James’s pow- 
der, ibid. Much heavier than any of the common earths and hones in a pulverized 
flate, ibid. The effects of fire on this powder, ibid. Antimony mixed with earthy 
matter, found by experiment in James’s powder, p. 320. Experiments with dif- 
ferent menflrua applied to James’s powder, ibid. The proportion in which James’s 
powder dilfolves in water ihewn, p. 324. Conclufions drawn from experiments on 
James’? powder, p. 323. Experiment with marine acid applied to James’s powder,, 
which had not been expofed to the adion of nitrous acid, or any other menflruum, p. 
344. Phofporic acid, lime, and antimonial calx, ingredients in James’s powder, 
p. 343. Experiments on James’s powder with fixed alkalies, ibid. Sulphur of anti- 
mony no ways neceflary to the formation of James’s powder, p. 360. The ingre- 
dients made ufe of in the formation of James’s powder enumerated, p. 367. 
Infinite feries, obfervations on, p. 146. New method of invefligating the fums of infi- 
nite feries, p. 295. 
Inflammable air, obfervation on the production of heavy, p. 176. Experiments relating 
to the decompofition of inflammable air, p.213. Inflammable air procured from* 
iron by means of fleam, p. 216. 
Infett. Defcription of the male lac infed in its perfed flate, p. 231. Defcription of 
the female lac infed in its perfed flate, ibid. 
Journal , meteorological. See Meteorological Journal . 
Iron , Account of fome appearances attending the converfion of call into malleable, 
173. Conclufions drawn from experiments on iron, p. 175. Grey iron contains & 
large portion of plumbago, p. 177. 
Ivory , the temperature of water has a fenfible effed on theexpanfion of, p. 13. 
L. 
Lac . See Chermes Lacca 
Lambeth , South, abflrad of a regifler of rain kept at, for the year 1789, p. 89.. 
Lane , Timothy, on human calculi, p. 223. 
Vol. LXXXI. L 1 1 
Lavas r 
