The thermometers ¢ and ¢ were so situated as to embrace be- 
tween them forty-five inches in the length of the pipe, exhibiting a 
surface of eight hundred forty eight and one fourth square inches. 
The following observations will show the efficacy of this part of the 
apparatus. When the thermometer t was 145°, t was 121°, t” 
109.5°; whole quantity abstracted 35.5°; part taken off by the pipe 
between ¢ and ¢” 11.5°. Hence, 32,4, per cent. of the whole dt 
minution was due to this portion of alee although it was only 16,7, 
_ per cent. (less than one-sixth) of the whole surface exposed. It will 
be remarked that in this part, the gas was compelled to move verti- 
cally downwards, while in the body of the drum it ascended some- 
what obliquely, and that too, through a medium of gas in the centre 
of which it may have formed a current, which being enclosed as it 
were, in a pipe of gas, (a very bad conductor) could not readily dis- 
charge its heat through the iron. 
- The mean result of seven experiments made in this manner was, 
that 335 per cent. of the heat taken off was abstracted by this part 
of the pipe. This preves that the form of a drum is by no means 
the most favorable f for aly Sie i The Gassened pipe would 
LL: LL: be al- 
Tod fn Sosa it toa a considerable extent. — 
Sn west? =a 
a gh ‘ 
RT. XVI.—The Rattle Snake, (Crotalus horridus, L.) disarmed 
ay the leaves of the White Ash, (Fraxinus Americana, Mich. f-) 
Communicated by Judge Samuen Woonprvrr, in a letter dated 
Windsor, December 4th, 1832. 
TO PROFESSOR SILLIMAN. 
sation Sir.—Last evening while perusing your very interesting 
Betceal, 1 found ia Vol. iii, p. 85, 2 communication to you by Prof. 
Jacob Green, giving an account of a large quantity of rattle snake 
skeletons, found in a cave near Princeton College ; Prof. Green clo- 
ses his communication with a passing notice of a popular story, 
among the former inhabitants of that town, that the leaves of the 
White ash were obnoxious to those reptiles. 
This brought to my recollection an occurrence connected with this 
abject, of which I was a witness, and now proceed torelate. 
the summer months of 1801, I resided in the north eastern 
part of the state of Ohio. Rattle Snakes were then very numerous in 
Vou. XXIII.—No. 2. 43 
