362 Dr. Ure’s new experimental researches 
as very erroneous, then ether itself is an exception to its own 
law, to use this paradoxical, though just expression. In 
consequence of his peculiar thermometric ideas, Mr. Dalton 
has abrogated the above law, which he had himself framed ; 
though it is curious to observe, in some respectable treatises on 
chemistry, both hypotheses detailed, without indicating their 
mutual incompatibility. M. Biot, likewise, far from imagining 
that the law had been repealed for 8 or 9 years, proposes to 
judge by its provisions of the total elastic force of every 
vapour at ioo° centigrade, to serve as the basis of the deter- 
mination of their respective specific gravities at that tem- 
perature.* 
My experiments show that from 105° to i 6 j°.s Fahren- 
heit, ether trebles the tension of its vapour, as water also 
does from 212 0 to 27 2 0 . 7 ; both containing nearly, but by no 
means exactly, equal intervals of the Fahrenheit graduation. 
According to Mr. Dalton’s corrected scale of temperature, 
we have, 
212 0 Fah. = 212® Dalton. 105 0 Fah. = 119° Dalton. 
273 F. = 256.4 D. 167.5 F. =176 D. 
real interval = 44.4 by Dalton. By Dalton 57 = the real 
interval of temperature. 
Thus we see, that while the interval for trebling the tension 
of ethereal vapour is 57 0 , that for aqueous vapour is only 
44°.4*, quantities that are to each other nearly as 100: 80. 
Hence, according to this eminent chemist, ether must take for 
* (t On peut calculer par la loi de M. Dalton, quelle doit etre, pour chacun d’eux, 
la force elastique totale de sa vapeur a la temperature de ioo degres.” Traite de 
Physique, Tome i. p, 393. 
