252 A Method of determining the specific Heat 
From this view of the subject we may proceed to find the 
quantities of heat necessary to produce a given change in the 
temperature of bodies, or what is called the specific heat. 
It is obvious that, if the principles I have advanced be correct, 
the quantity of expansion at any temperature will be equal to 
the quantity of heat required to raise the body to that tempera- 
ture. Let the specific heat of the body fixed upon as a standard 
be denoted by unity, or 1; and its expansion for any given 
change of temperature =E: also let e be the expansion of the 
same magnitude of any other body for the same change of tem- 
perature. Then nye 
Rese: sis = = the specific heat of a body of the same bulk. 
Consequently, if the same body be the standard of specific heat 
and specific gravity; and S be the specific gravity of the body of 
which the expansion is e ; 
= = the specific heat of a body of the same weight. 
In the annexed table it will be seen that the specific heats, ac- 
cording to this rule, do not agree very well with those obtained 
by other modes of calculation; for it is to be remembered that it 
is not a case that can be submitted to direct experiment. Inthe 
case of mercury the results are very near. ‘The expansion of the 
different bodies is from the tables in Thomson’s Chemistry, vol. i. 
and specific heats, in the last column, are from the same volume, 
pages 112 and 113. 
Table of the specific Heat of Bodies. 
Spec. heat | Spec. heat | Spec. heat of 
: Expansion of bodies of|uf bodies of bodies of the same 
Substance. in bulk, | the same | the same welght:—from 
bulk weiglit, ona a ieee 
Water.......| 0:0466 | 1-0000 | 1-0000 | 1-0000 
PM Naty ».., 0375 | 8-047 | 6662-8 | 
Alcohol...... O-11 | 2°36 2:883 | 0°76 
Fixed oils... .| O'S 1-716 18 | 0-528 
Mercury .....| 0°02 0-429 =| 00318 | 0-038 
Zinc ........| O'008S | O-1888 | 0-026 0:09438 
i bo eee 0:0024 | 0:0515 | 0-0215°) — 0-187 
Tin.........| 0:00651| 0°1397 | 0-0177.| 0068 
Lead........} 0°00855| 0-1885 | 60161 | 9:050 
Brass .......| 0°00588)| 0°11974| 0-01438 | © 0°11238 
Copper......| 0°00516; 0:1107 | 0:0125 O-111 
Leap} a <Sesaets dm 0-00366| 0:7855 | 0-01 O13 
Cast iron ....| 0°00333| 0-7146 | 0-01 
Hardenedsteel| 0:00323| 0-693 | 0:008S | 
Granting 
