INDEX. 



page 



Ornithorhynchus paradoxus, observations on its head, - 432 



P 



Pipes, on their harmonic sounds, - - - 121 



Plates, on their vibrations, - 140 



Poker, hot, on the reflection of its heat, - - 299, 306 



Presents received by the Royal Society, from November 1799 to 



July 1800, _____ 729 



Prismatic colours, experiments on their heating power, _ 256 



— — experiments on their illuminating power, 262 



on the reflection of the heat that accompanies 



them, ______ 298 



on the refraction of the heat that accompanies them, 310 



R 



Rain, register of, at Lyndon, in Rutland, - - - 46 



Rays, on the solar and terrestrial ones that occasion heat, 293, 437 



on the heating power of coloured ones, - - 256 



on the illuminating power of coloured ones, - 262 



on the reflection of invisible ones, - - 302, 304 



on the refraction of invisible ones, - 284, 317, 319 



on the condensation of invisible ones, - 304, 317 



on the different refrangibility of those of heat, - 271,438 



on the focus of those of heat, _ _ 444 



— — on the transmission of heat-making ones, - 445> 5 2 ° 



of invisible ones, - - 485,520 



whether light and heat be occasioned by the same, or by 



different ones, - 506 



Refraction, atmospherical, on double images caused by it, - 239 



— — extraordinary instance of, - 720 



Reversions, contingent, on determining the values of those in which 



three lives are involved in the survivorship, 22 



Rods, on their vibrations, - - - - 140 



s 



Scale, horny, experiments on, - - - - 374 



Scales of Jish, experiments on, ... 373 



Shells, observations on, - 327, 357 



Skin, experiments on, - 3695378 



Silver, on a fulminating one, - 233 



Soap, Chaptal's, remarks on, - 392 



Sound, experiments and inquiries respecting it, - - 106 



ocular evidence of its nature, - - - 115 



on its velocity, - - - - - 116 



