on some of the leading Doctrines-of Caloric, fc. 97 
- with Mr. Dalton, we consider our thermometric scale, as very 
erroneous, then either itself is an exception: toits own law, to use 
this paradoxical, though just expression. In, consequence of his 
peculiar thermometri¢ ideas, Mr. Dalton has abrogated the above 
law, which he had himself framed ; though it is curious to ob- 
serve, in some respectable treatises on chemistry, both hypo- 
theses detailed, without indicating their mutual incompatibility. 
M. Biot, likewise, far from imagining that the Jaw had been re- 
pealed for eight or nine years, proposes to judge by its provisions 
of the total elastic force of every vapour at'}00° centigrade, to 
serve as the basis of the determination of their respective specific 
gravities at that temperature *. 
My experiments show that from 105° to 167°*5 Fahrenheit, 
ether trebles the tension of its vapour, as water also does from 
212° to 272°°7; both containing nearly, but by no means ex- 
actly, equal intervals of the Fahrenheit graduation. According 
to Mr. Dalton’s corrected scale of temperature, we have 
212° Fah.=212° Dalton. ~-105° Fah.=119° Dalton. 
273\'F. » =2564'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°, that for aqueous vapour is orily 44°4 ; 
quantities that are to each other nearly.as'100:: 80. . Hence, 
according to this eminent chemist, ether nrust take for treébling 
“the force of its vapour a fifth part more heat than water. does. 
I hope presently to be able to adduce satisfactory’ experimental 
evidence, that our thermometric indications are not at all so un- 
equable as Mr. Dalton conceives. 
‘Meanwhile, in examining elosely the table of the vapour of 
ether, a beautiful analogy with that ‘of. water. presented itself... 
The series of ratios representing the progression of the latter be-° 
ing lowered a single step, will accurately fit'the former. At 30 
inches of elasticity 1*23 was our initial number for aqueous va- 
pour 5. for ethereal, it becomes 1*22 5 increasing or diminishing 
by unity each time inthe second decimal figure; according as we 
descend or ascend by intervals of 10° of the Fahrenheit scale. 
The following is a general view of the results. 
*“ On peut calculer par Ja loide M Dalton, quelledoit étre, pour chacun 
deux, la force élastique totale de sa yapeur a lay température de 100.de- 
grés.”—Traité de Physique; tome i, p, 393. 
Vol. 53. No. 250, Feb. 1819. G TABLE 
