INDEX. 



eonftitutlon of mixed gafea, 52, 160.-- 

 On atmofpheric air, 107, ia6. — On the 

 neceflity of atmofpheric oxigcn to the 

 procefs of vegetation, 217, 141 



Graham's pendulum) 229 



Greenough, Mr. on a blow- pipe a&ingby 

 the preffurc of water» a5»— His correc- 

 tion of the account, 143 



Gridiron pendulum, difficulty of prevent- 

 ing flexure in, 228 



Grimaldi, 130 



Gripe, afting on the naves of wheel-car- 

 riages, 177 



Grubbens, Michael de, on the preparation 

 of Chinefe foy, 237 



Gum, is a generic term, 70 



■ Arabic, fubftitutes for, 232 



H. 



Hall, Sir James, his experiments on the 

 tfft&s of heat modified by compreffion, 

 98 



Halley, 212 



Harding, Mr. his difcovcry of a new mov- 

 ing ftar, 112, 142 



Hanifon, F. Efq. on the laws of galva- 

 nifm, 240 



HalTe, 283 



Haffenfratz, on the caufes which incrcafe 

 the intenfity of the found In fpeaking- 

 trumpets, 283 



Hatchett, C. Efq. his analyfis of a triple 

 fulpburet of lead, antimony, and cop- 

 per, i4.—0n a method of preparing 

 malleable platina, 65 



Hauy, Abbe, obfervations on his theory 

 of cryftallography, 27, 79 



Hearing is not the confequence of the re- 

 fleftion of found, 285 



Heat, enquiry into the nature of, and the 

 modes of communication, 58, 193.— 

 Experiments on its efFefts when modi- 

 fied by compreffion, 98. — Analogy with 

 light, 202.-~Obfervations on the pro- 

 pagation of, in fluids, 207.— -Increafes 

 the dimeniions of bodies^ Z47.-*>Aug- 



ments the abforbent power of charcoal* 

 260— Developed during the compreffion 

 of air, 302. 



Heat, invifible rays of, experiments on the 

 140 , 



— latent, of different fubftanccs, ex- 

 periments on, 45 



— -— radiant, Inftruments for meafuring, 

 62 



Henry, Mr. his reply to Mr. Cough on 

 mixed gafes, 126 



Hens, on the commerce of their eggs, 264. 

 — Modes of management of, 265 



Herfchell, Dr. 141 



Hewfon, Mr. 139 



H. G. on the computation of fquares and 

 cubes, 123, 171 



Hidrogen gas, fufpenfion of zinc in, 24. 

 •— A£lio» of charcoal on, 263 



Hjelm, 294 



Honey is converted into wax by the bees, 

 184.— The principles of wax refide in 

 the faccharine part of, 191 



Horizontal moon, on the enlarged appear- 

 ance of the, 164 



Horn, total volatilization of, 104 



Horfe-powers, method of eftimating the 

 value of fteam engines in, 214 



Huber, on the origin of wax, 182 



Hutton, Dr. 3, 98 



I. 



Ice, on the latent heat of, 51. — ^Deprefles 

 the temperature by radiation, 195. — Cy- 

 lindrical part of water in a mafs of, 207. 



Jeffi)p, W. Efq. on an improvement In the 

 procefs of blading rocks with gunpow- 

 der, 230 



Images, optical, do not vary with the pu- 

 Pil^ ^35 



Ingenhouz, M. 217 



Inftrument, compound eleftrical, 19 



— — — for counting the lifts from a 

 mine, 114 



" - ■■' for delineating ovals, 123 



■ " ' ■ for drawing in perfpeilive from 



nature^ 122 



Inftrument 



