58 REPORT—1840. 
M. Boblaye in Greece. d - 1%. -for=150!met: 
38 observations collected by Ramond 1°c. ,, 164:7,, 
And for Gay Lussac’s aérostat alone 1°c. ,, 184 ,, 
as we might expect, from its great elevation*. 
53. We have reason to believe, that in high latitudes the 
decrement is less rapid than in low ones; and M. Aragof has 
called particular attention to cases in which an actual inversion 
of the usual law occurs in the latitude of Spitzbergent, and on 
Arthur’s Seat, near Edinburgh, during extreme cold§. 
54. The decrement of temperature in the atmosphere, with 
reference to its constitution, has been considered in a lengthened 
series of papers, of which we cannot attempt an analysis, by 
M. Biot, lately published in the Comptes Rendus de ? Académie 
des Sciences de Paris, and in the Connaissance des Tems. 
55. It has been considered in a more restricted point of view 
by Prof. Challis|], who has deduced from the properties of air, 
with regard to specific heat, a fall of 1° Fahr. for 186 feet, 
which is about a half too rapid. Mr. Lubbock, on the other 
hand, proceeding @ posteriori from Gay Lussac’s aérostat, has 
generalized the connexion of temperature and pressure so as to 
find the height of the atmosphere]. 
56. Any attempt, however, to connect the temperature and 
density of the atmosphere by laws such as regulate a laboratory 
experiment, must fail, in consequence of the incompleteness of 
the data. The increased specific heat of rarefied air is by no 
means the only cause of the diminished temperature of the 
higher regions of the atmosphere**. The higher the stratum, 
the more transcalent the medium which separates it from the 
planetary spaces, and therefore the freer will be the radiation in 
* To convert metres for 1° cent. into English feet for 1° Fahr., use the con- 
stant factor 1°8227 [log. 9:26072]. 
+ Comptes Rendus, vii. 206. 
t Observed by Captains Sabine and Foster. 
§ Observed by Dr. Lind, 31 Jan. 1776. Phil. Trans. 1777. 
|| Cambridge Transactions, vol. vi. 
q On the Heat of Vapours, p.21. Lond. 1840. 
** On the specific Heat of Gases, see Dr. Apjohn’s experiment by the use of 
the moist bulb hygrometer, (Brit. Assoc., Sixth Rep., Sect. Proceedings, p. 33,) 
and Suerman’s Thesis, De Calore fluidorum elasticorum specifico, 4to. Trag. 
1836, for which I was indebted to the ever-ready kindness of our late associate 
Dr. Moll. In these essays we find a new proof of the inexhaustible ingenuity 
by which philosophers have endeavoured to make amends for the practical dif- 
ficulties of the direct problem: it is curious to see one and the same question 
treated, now by the aid of the calorimeter, now by observing the tone of an 
organ-pipe, and now by a dew-point experiment! Unfortunately, we cannot 
add that these various methods give the desired concordance of result. Re- 
gnault’s are the latest experiments on the specific heat of simple{bodies. Ann. 
de Chim. \xxiii. 1. (1840.) 
