708 
DE. E. SMITH ON THE CHEmCAE 
active ; and both were nearly uniform in July, August, and September, when the respira- 
toiy changes were low. To show, however, that there is no invariable relation, it may 
suffice to mention that with a pressure of 29-51 inches the carbonic acid was 8-19 grs. 
and 7-13 grs. in May and September respectively. 
Thus, after a minute inquiry into the influence of these two agencies, there can be no 
doubt that the influence of season is far more than can be explamed by these meteoro- 
logical conditions, and that it is one which demands further accurate observation, and 
particularly in reference to the influence of light as it increases in intensity m the 
spring. It is, moreover, of the utmost importance to bear in mmd that thty influence 
is felt in every action of the system ; for as the quantity of carbonic acid vanes with the 
season, so do the quantities evolved under the influence of exertion and food. Hence, 
in stating the influence of any agent, it would be erroneous to give absolute numbers, 
under the idea that they would be true at all periods of the year. This is particularly 
applicable to the next subject of inquiry; for my experiments have shown that the 
same exertion, as for example walking at a given rate, produces effects upon the respira- 
tion considerably greater in winter than in summer. 
rjVofo, April 1859.— Since the foregoing remarks were written, I have completed t e 
observations during the cycle of the year ending March 31, 1859 ; and the quantity o 
carbonic acid evolved, with that of the air inspired and the rate of respu-ation, have been 
added to Plate XXXIV . , • n • ii . 
At the end of October the quantity of carbonic acid evolved had materiaUy mcrease , 
and throughout November and December and the beginning of January the mcrease 
was progressive, so that the quantity had attained to upwards of 8* gi-s per mmute. 
Throughout the remaining portion of January, as well as in Februai) an arci, ne 
quantity evolved was nearly stationary, and even more uniform than at any other perioc 
of the year; but at the end of March it again increased, and on March nl, 18o., was 
very nearly the same as was recorded on March 31, 1858, viz. 8-25 grs. and 8-51 grs. 
^'^The quantity of air inspired per minute increased from an average of 395 cubic niches 
in October, to 114, 429, and 447 cubic inches in November, December, and January, m 
their order. lo.Qt^w^ov 
The rate of respiration in like manner increased on the average fi-om ^ P 
minute in October, to 10-87, 11-16, 11-73, 11-36, and 11-38 in the months of Novem- 
ber, December, January, February, and March, and did not reach to the elevation 
recorded in 1858. . j „ .-inv.vfT.no 
The temperature after October remained, during the wmter months, at a^^ 
varying from 43°T to 48°-9, and exhibited marked perturbations at the en o i o^em 
her and the beginning of J anuary and March. 
The monthly averages are appended to Table VI. 
The variations observed from day to day were frequently attributable to the causes 
described in page 702, and tended further to corroborate the deductions then ma e ; an 
