} Quantity of Heat evolved from Atmospheric Air. 223 
, 
| I have deemed it necessary, for a full elucidation of the subject 
before us, to append a table of deductions, drawn up from some of 
the data furnished by the preceding tables. In explanation of 
this table it may be stated that the first column is intended to 
the 3d is designed to show the difference, in the same water, 
and the 5th the same tension as corrected for excess of temper- 
ature, su 
To enable us to compute the effects without great and undue 
labor, it is necessary to reduce both the air and the water, used 
in the experiments, to some common measure or weight. The ais 
pound weight as the most convenient standard, has been adopted. fey 
By reducing columns ten and twelve, of the preceding tables, to” 
the common rate, we have obtained column 6 of the following 
able. ; : 
The 7th column shows the quantity of heat set free by the © ¢ A 
condensation of one pound of air at the specific heat of air. The . 
figures in the column are ascertained by assuming that the specific. - 
eat of air—assigned by Delaroche and Berard, viz., 2669 aid 
water being 1:0000—is correct, and then multiplying the quantity %? 
by the number of degrees, F.; one d of air heats oné pound re 
of water, under a given degree of compression, as shown in ot 
jmn six. It is in truth a mere representation of the intensi of 
-heat evolved by the simple condensation of air. * bi 
Olumns 8 and 9 show the quantity of heat—expressed in #* 
the number of pounds of ice it would melt a, 
capable of producing in twenty- nd 
The LOth and 11th columns sh 
of heat, fic héats of: 
yer close appro: jmatio 
Efor all tensions 
: a 
oor. 
3 P cae a » 2 
+ 
