MfSCELLANEOUS NOTICES, &C. 
a i 
xln 
the maximum temperature is seldom above 85, and 10° ad¬ 
ditional may easily be registered in a small circular shed ve¬ 
randah which is neither impervious to the direct nor 
reflected rays of the sun. 
(15) It is deli cions to see with what unctuousness the 
Doctor lays down the law. The building must be circular \ 
this sound Aristotelian, some occult virtue in a circle perhaps, 
and as Aristotle says a circle has no contraries there is no 
use in opposing this arrangement. According to the writer 
the;e should be no walls, then how does he provide against 
reflection of the sun’s rays, against local currents, and again t 
undue lowering of the thermometer at night by terrestrial 
radiation ? I do not know what the dimensions of the 
budding are, but should not imagine very considerable if 
constructed solely for a thermometer. If of small size, 
then I say the Doctor might as well put his thermometer in 
a six dozen case, place it in the sun, i nd look out for the 
maximum temperature of 95°. If the Doctor will but take 
the trouble he will find that in that small temple of the 
winds there is a different temperature at every foot of 
altitude, gradually decreasing from the ground to a certain 
point, and then increasing upwards from that point to the 
roof. Has the Doctor laid his finger on the very spot the 
minimum of this line? To the temperature which his 
thermometer shows what deduction has he to make for the 
absorption of heat by the building which is of course 
communicated to the thermometer and which must be eli¬ 
minated before the true temperature is deduced ? It is this 
excess which I have attempted to provide against, and to 
give as nearly as possible the true temperature and by all 
the means in my power to guard against the absorption of 
the sun’s rays. It was for this reason I made the walls 
18 inches thick and painted them white, that, if any of the 
sun’s rays should by accident impinge on the walls, they 
correspondent appears to do with respect to that which siood in the Magnetic 
Observatory. We have always admi'ted that the max*ma were y eiily 
influenced by the want of due protection from the indirect action of the suit's 
lays. But with respect to the minima we believe dial they t*u!v registered the 
actual tempera lure of the tx'prual air They were suspended m that air 
against a plas.k wall which soon cools down to (hat temperature, and an 
atlap roof wjs interposed between them and the sky The only sufficient 
explanation of the fact that these ihermometers indicated 6° lower than that 
at the Observatory ever did, apppars to us to he this, that the u traul air 
on entering the Observatory was raised several decrees by absorbing heat 
from the wall Ac We may add that we carried our theimometers to the 
Observatory to be examined by our correspondent and he appeared to be 
satisfied they were free from delects.—E d, 
