Proceedings of Societies. lib 



The agreement with M. Regnault's table is also extremely close ; and 

 considering the ordinary limits of error of such observations, the writer 

 considers it nearly indifferent for elevations under 13,000 feet which 

 method of calculation be used. 



The consistency of the results shews that the method of observation 

 (which differs in some respects from that commonly used) and the gra- 

 duation of the thermometers were satisfactory. 



On carefully examining T)r Joseph Hooker's detailed results, (obligingly 

 communicated by him), which that naturalist considered to be incompati- 

 ble with Professor Forbes's formula, it is shewn that the inconsistencies 

 of observation are so considerable, that it is difficult to give a decided pre- 

 ference to one formula rather than another, for the purpose of represent- 

 ing them ; but that up to heights of at least 13,000 feet, a linear formula, 

 or one which assumes the lowering of the boiling point to be exactly pro- 

 portional to the height, seems to express the observations as well as any 

 other ; and the rate of diminution is almost the same as that deduced from 

 Professor Forbes' observation, or a lowering of 1° for 538 feet of ascent. 



The author has little doubt that M. Regnault's table, (which was not 

 published when he last wrote), does really represent the law according to 

 which water boils more accurately than the simpler linear formula, though 

 the difference is in most cases insensible. For all ordinary heights (or 

 up to 12,000 feet) Regnault's table may be more accurately represented 

 by the formula 



h == 535 T. 



Where h is the height in English feet, T the lowering of the boiling 

 point in Fahrenheit's degrees, reckoning from 212.° But he finds that 

 Regnault's table may be represented in every case which can occur in 

 practice, and with almost perfect accuracy, by the following formula, 

 which is nearly as easy to use : — 



h = 517 T + T 2 . 



On the Chemical equivalents of certain Bodies, and the relations 

 "between Oxygen and Azote. By Professor Low. 



The author commences his paper with a review of the opinions enter- 

 tained by Dalton, Berzelius, and others, regarding the equivalent numbers 

 of hydrogen, oxygen, nitrogen, and carbon, which have been differently 

 fixed, according as we start from combination by weight or by volume. 

 He remarked that while either view was perfectly suited to explain all 

 the general phenomena of decomposition, yet since chemists had begun 

 to examine the phenomena of substitution, it became apparent that it 

 was absolutely necessary to employ the equivalents determined by weight. 

 The author then proceeds to show that on a proper comparison of the 

 properties of these elements, and of the constitution of their compounds, 

 their atomic weights must be Hydrogen 1 , Carbon 6, Nitrogen 7, Oxygen 8. 



Reference is then made to the nature of azote, and to the opinion more 

 than once expressed since its discovery in 1772, that it might be a com- 

 pound, and to the views of Davy and Berzelius, the latter of whom sup- 

 posed it must contain an inflammable base, which he proposed to term 

 Nitricum. The author stated that he had long since arrived, by an en- 

 tirely different line of argument, at the conclusion that nitrogen was a 

 compound substance containing carbon ; and as no other element can pos- 

 sibly combine with that substance so as to produce a compound whose 

 equivalent shall be 7, except hydrogen, he concludes that azote is 

 actually represented by the formula CH. Pursuing the same line of ar- 

 gument, he pointed out that oxygen might be a compound of azote and 

 hydrogen, and referred to certain properties of ozone as indicating its 



