2$ Mr. Herapath on True Temperature^ and the [Jan. 



ANNALS, VOL. II, {New Series,) 



PHiEKOMSKA 



Developed. Confirmed bjf 



74. P. 374. — A theorem expressing the 

 apparent evaporation. 



N. B. This theorem is misprinted ; it 



jlhould be -^ ; (T t - T' E). 



75. Ibid. — Vapours in vacuo can only Dalton. 

 support a given pressure according to the 



temperature, but mixed with sufficient gas ^ 



can support an indefinite one. 



Let T = ij5 f be the tension of the vapour at the temperature t, and E the elasticity of 

 any gas occupying the space S at the temperature T. Then if e be the elasticity of the 



S i* 

 mixture, and s the space occupied, we have c = E -— , + f f. This is a more general 



equation than that given by 31. Biot in the Traits de Physique. It is, however, like 

 his and all others of this kind, not mathematically true, in consequence of not taking into 

 account the quantity of gas absorbed at the temperature t. I shall probably, in a ftiture 

 <Xttnmunication, consider this circumstance, and show how to make the necessary 

 allowance. 



76. P. 275.~Rarefaction of air pro- 

 motes desiccation. 



77. Ibid. — Method of obtaining a Tor- 

 recellian vacuum. 



78. P. 376, 377, and 37 S.— Formula 

 for determining the apparent and absolute 

 qnantity of vapour at any time in the at- 

 mosphere, with a method pointed out of 

 verifying by them the truth of the theory. 



79. P. 381— Formula of the effect of 

 cold water in drying a room. 



80. P, 382. — Apparent evaporation is 

 proportional to the velocity of the current 

 of air passing over the surface of the fluid. 



81. P. 384 — Either a current or an 

 agitated air increases apparent evapora- 

 tion, and diminishes the temperature. 



82. Ibid. — Water of a low temperature, 

 or even ice in a current or an agitated air, 

 may lose more weight by evaporation in a 

 given time than water of a higher temper- 

 ature in a still atmosphere. 



83. P. 384, 385, 386, 387, and 388.— 

 Water commonly colder than the atmo- 

 •phere. 



84. P. 435.— Theorem for the tension 

 of aqueous vapour in contact with its fluid 

 at all temperatures. 



85. P. 440. — Temperature of no eva- 

 poration — 130^ Fahr. 



86. P. 441 — The temperature of ebul- 

 lition higher than the temijeraturc of ten- 

 sion. 



87. P. 444. — Baromerin of ice to baro- 

 merin of water as 1 9 to 22. 



88. P. 445.—" Capacity " of water 

 being I , that of ice is '86. 



89. P. 447.— Theory of the calorime- 

 ter. Calculation of capacity of iron plate 



116. 



Leslie, &c. 



Has been partially tried by Smeaton, 

 &c. 



I shall be glad to see these formulae 

 brought to the test of experiment. 



Leslie. 



Leslie and Dalton. 



I think the superior evaporation of ice 

 is to be found in Clare, Rowning, or 

 Hamilton. 



Wells and myself. 



Experiments of Robison, Dalton, Ure, 

 and Southern, but principally Ure's. 



The theorem confirmed by Ure's expe- 

 riments. 



Shown from the experiments of Robison, 

 Dalton, and De Luc 



Experiments of Black, Kirwan, Irvin> 

 Thomson, and Lavoisier and Laplace. 

 Mean of Irvin and Kirwan, -85. 



Lavoisier and Laplace, '1 H . 



