Index. 301 



producing it as an agent in chemistry, 1 11 to 123. Sec 

 also Caloric. 



Hermeiical sealing, how effected, ii. 215. 



Hoar frost, i. Q5. 



Horizon, explanation of the sensible and the rational, 263, 

 26'4. 



Hurricanes, their ravages, and probable cause, i. 88 in 

 the We^t Indies, ib. 



Hydraulics, lecture on, i. 48 explanation of this name, 

 ib. cause why fluids rise to the level of their source, 

 ib. principle of the syphon, and experiments with it, 

 50. 52 principle of intermittent springs, 52 of the 

 common pump, 53 of the forcing-pump, the fire-en- 

 gine, and steam-enoine, 57 to 60. 



Hydrocholoric acid, nature of the, ii. 157. 



Hydrogen, or inflammable air, a simple substance in che- 

 mistry, ii. 36 chemical account of it, 48. 51. 201. 

 223. ' 



Hydrometer, principle of this instrument, i. 46. 



Hydrostatics, lecture on, i. So explanation of this name, 

 ib. water proved to be not incompressible, ib. princi- 

 ples concernino; the pressure of fluids, 36, 37, 3Q. 42, 

 43 method of operation of some \vater-works, 35 

 supposed constitution of fluids, 38 springs on the 

 tops of mountains accounted for, 3Q -the hydrostatic 

 paradox, ib. the hydrostatic bellows, 41 cause why 

 the banks of rivers, &c. blow up, 42 principle and 

 proportion of a ship's drawing water, 43 principle of 

 the tables of specific gravities and the hydrostatic balance, 

 ib. method of ascertaining the density of different 

 fluids, 45 explanation of the hydrometer, 46. 



I. 



Ice, cause of the cavities found in, ii. 5Q disputes con- 

 cerning the rarefaction of, 7!, 72 liquefaction of, by 

 nitric acid, 73, 74 experiment of dissolving with 

 nitric and sulphuric acid, 147- 



Inclined plane, principle 01' this mechanical power, i. 

 241. 



Indigo, chemical remarks on. ii. 281. 



Insolation, meaning of the K-rai, ii. 113. 



Intermittent springs, what erased by, i. 52. 



