June x, X92X 
Some Fundamentals of Stable Ventilation 
363 
Table XVII .—Air flow per head to maintain 0.167 per cent carbon dioxid 
Species. 
Carbon dioxid pro¬ 
duced per day. 
Air flow 
per day. 
Air flow 
per hour. 
Air flow 
per hour 
according 
to King. 
Cows. 
Gm. 
0 7, 686 
s. 138 
1,708 
740 
Cu.ft. 
138. 348 
92. 484 
3 °* 744 
13- 3 2 ° 
Cu.ft. 
82, 843 
55,379 
18, 410 
7.976 
Cu.ft. 
3,452 
2,307 
767 
332 
Cu.ft. 
3 , 545 
4 , 303 
I , 394 
909 
Horses. 
Swine. 
Sheep. 
a Average carbon-dioxid production by cows in milk. 
A glance at the last two columns of Table XVII reveals that while 
King's air flow for cows agrees fairly well with that computed from the 
carbon dioxid produced, those for other species differ very widely. In 
other words, either King’s figures for volume of respiration in other species 
than cattle are too high or his assumption of a uniform percentage of 
carbon dioxid in the expired air is erroneous. At any rate, the actual 
carbon-dioxid production would seem to be the proper basis upon which 
to estimate the rate of ventilation required. 
TEMPERATURE) DIFFERENCE BETWEEN THE STABLE AND OUTSIDE AIR 
As already shown, a considerable part of the motive power for stable 
ventilation is derived from the heat eliminated by the animals, and 
this heat is also depended upon to maintain the proper temperature in 
the stable. Obviously, the difference in temperature that can be main¬ 
tained between the stable air and that outside depends, other things 
being equal, upon the balance between heat production and heat loss in 
ventilation. The maximum value of this difference can be computed, 
when the rate of the air flow and the heat production values are known, 
on the assumption that no heat is lost by radiation through the walls of 
the stable. It should, however, be borne in mind that it is only the heat 
eliminated by radiation and conduction that should be made the basis 
of the computation, since the latent heat of water vapor, as already ex¬ 
plained, is not available for this purpose. 
method of estimating the temperature difference 
Assuming for the purpose of illustration an air movement correspond¬ 
ing on the one hand to King’s standard and on the other hand to the 
amounts computed in Table XVII from the carbon-dioxid production, 
the temperature difference that can be maintained by the different 
animals can be determined in the following manner: One calorie of heat 
can raise the temperature of a pound of water about 4 0 F. Since the 
specific heat of air is 0.237 and since 100 cubic feet of air weigh 8 pounds, 
one calorie of heat can raise the temperature of 100 cubic feet of air 
o ~ 2 37X8 * ° r 2,I °* ^° nsec l uen tly the heat required to warm by i° 
