470 Scientific Intelligence. _ June, 
the converse of this, and which I shall forthwith make the sub- 
ject of experiment. Under such circumstances, the march of 
the hygrometer must be noted, and this instrument will become 
an indispensable accessary. At inconsiderable heights, this will 
not make a notable difference ; but at great altitudes the amount 
will be material. Hence the results of the Rev. Mr. Wollaston’s 
interesting researches. 
I should like to know whether the temperature of snow has 
been observed to maintain any ratio with its altitude. In cross- 
ing the Boeketta, I found the temperature of the snow to be 
30° Fahr. On the 8th of January last, at 10 o’clock, a.m. the 
snow about 1500 feet lower than the station of the Grande Croix, 
on Mount Cenis, was 22° Fahr. At the Grande Croix at lla 
30’, a.m. the temperature of the atmosphere was 22°, while 
that of the snow was 21° Fahr. The question is at least mte- 
resting.* j 
It has, I know, been presumed, that animal heat continues 
uniform im an exaltation of temperature; and Mr. Brodie has 
ascribed its production to the operations of the brain, which had 
hitherto been supposed referable to the action of the lungs ; but 
Dr. John Davy found a difference of about one degree of excess 
in tropical climes. 
In the Stuffa San Germano, on the border of the Lago Agnano, 
near Naples, I found the animal temperature to be 102° Fahr. ; 
the medium was 110°. I remained here neariy half an hour to 
examine chemically the natuve of this subterranean vapour, so 
that the excess cannot be entirely ascribed to a sudden transi- 
tion. The thermometer held in the aperture through which the 
sulphureous vapour entered, exhibited a-temperature of not less 
than 160° Fahr.+ It enters by jerks, which was well demon- 
strated by corresponding oscillations of the mercury in the ther- 
mometer. The air in the chamber was extremely dry, and 
Leslie’s hygrometer { completed its range of 80°. I think I 
have not been deceived in noting the animal temperature on the 
Simplon and Mount Cenis at a decrement of several degrees. 
I have the honour to be, Sir, 
Your very humble and most obedient servant, 
J. Murray. 
* From the nonconducting powers of snow with respect to caloric, it might at 
least afford an equable mean of determining the medium temperature on given 
altitudes, 
+ [remember Mr. Davenport’s experiments on boiling tar interested me at the 
time. I placed my hand in the elevated temperature for some time without suffering 
the least inconvenience, and so long as the epidermis was free from moisture, 
{ Lhave found this instrument among the Alps a most valuable acquisition. In 
the morning before I pursued my journey, if there was no evaporation indicated, 
only a few degrees of fall, 1 could always conclude with confidence on rain during 
the day. : 
/ 
