INDEX. 



page 



Heat, on the laws to which it is subject, - - 296 



on the reflection of that of the sun, - 296, 298, 302 



■ of that of a candle, - - 297 



of that of hot iron, - - 299, 306 



of that of fire, - - 300,305 



on the refraction of that of the sun, - 284, 308, 310, 317 



of that of a candle, - - 308 



of that of fire, - - 3 ll >3*5 



of that of hot iron, - 313, 319 



— on the focus of its rays, - 444 



— on the transmission of heat-making rays, - 445, 520 



— of terrestrial flame-heat, - 462, 524 



■ of the solar heat which is of equal re- 



frangibility with red rays, - - - 470, 520 



of that of fire, - - 476,524 



of invisible solar heat, - 485, 520 



of invisible terrestrial heat, - 490, 524 



■ on its transmission through colourless substances, - 449 



through coloured glasses, - 453 



through liquids, - - 456 



through scattering substances, - 458 



■ on the scattering of solar heat, - 497 

 whether it be occasioned by the same rays as light, or by dif- 

 ferent ones, - 506 



Heavens, on the time it would take to sweep them, - 84 



Hellins, the Rev. John. A second appendix to the improved 

 solution of a problem in physical astronomy, inserted in the Phi- 

 losophical Transactions for the year 1798, containing some further 

 remarks, and improved formulae for computing the coefficients A 

 and B ; by which the arithmetical work is considerably shortened 

 and facilitated, 86 



Henry, Mr. William. Account of a series of experiments, un- 

 dertaken with the view of decomposing the muriatic acid, - 188 

 Herrings, experiments on their light, - - - 1 63 



Herschei, William, LL. D. On the power of penetrating into 

 space by telescopes; with a comparative determination of the 

 extent of that power in natural vision, and in telescopes of va- 

 rious sizes and constructions ; illustrated by select observations, 49 



Investigation of the powers of the 



prismatic colours to heat and illuminate objects; with remarks, 

 that prove the different refrangibility of radiant heat. To which 

 is added, an inquiry into the method of viewing the sun advan- 

 tageously, with telescopes of large apertures and high magnifying 

 powers, - - - - 255 



5B2 



