320 



A method of cooling the Air of [No. 10, 



NEW SERIES. 



pending on no theory of heat, but merely the fact of heat being 

 the cause of the apparently self-repulsive or expansive power of 

 gases, and on the well-determined amount of this expansion of gas 

 by heat, viz. for 1 ° Fahr. 



On this well grounded idea he has computed a table, showing 

 the decrease and increase of temperature on certain amounts of ex- 

 pansion and compression of air ; and the truth of the table, and the 

 idea on which it is founded, are well borne out by the close agree- 

 ment with the Kinneil experimental results already detailed. The 

 table is as follows : — 



tt • a- • i.v Variation of tem- 



Variation m the , e on . 



•, n n perature from 60 - 



bulk ot a portion r ^ , , j 

 . r .bahr. produced 



oi air. , i -i j 



there by degrees 



Expanded to 00 .... 508-0 



1000 vols... 457-2 



500 .... 444 0 



200 421-0 



100 .... 398 0 



50 .... 370-0 



20 .... 320-8 



10 .... 272-2 



5 .... 210-9 



3 .... 155-9 



2-5 .... 133-7 



2 .... 104-8 



1-9 .... 979 



1-8 .... 90-4 



1-7 .... 82-3 



1-6 .... 7.^7 



1-5 .... 64-2 



1-4 ... 53-9 



1-3 .... 42-5 



y . ,. . Variation of tern- 



Variation in the frQm QQ 0 



bulk of a portion ^ 7ahr> produced 



of air. 



thereby degrees. 



1»2 

 11 .... 

 10 .... 

 Compressed to 0-9 of the vol 



0-8 .... 



0-7 .... 



0-6 . 



0-5 . 



0-4 . 



03 . 



0-2 . 



0-1 . 



0-05 . 



0 02 . 



001 . 

 0 005. 

 0002. 

 0-00 1 . 



o-ooo. 



30-0 

 159 

 0-0 

 17-1 

 39-1 

 64-2 

 94-3 

 132-0 

 181 5 

 251-0 

 360-7 

 586-4 

 870-9 

 + 1363-5 

 + 1850-1 

 + 2462-8 

 + 3524-0 

 +4572-0 



To adopt this table to any other initial temperature than 60 ° 

 Fahr. add Y ^ to the tabular quantity for every degree by which 

 the temperature is higher, and subtract the same for every degree 

 by which it is lower. 



The merest glance at this table shows the advantage of using 

 the lowest compression compatible with the quantity of cooling 

 required ; and further, that this degree of compresson will, in all 

 ordinary cases, be so very trifling that the expansive force of the 

 escaping air would not overcome the friction of the apparatus on 

 which it would have to be employed if utilised mechanically. The 

 machine resolves itself, therefore, into a pump, as simple as could 



