Chap. XXX VII I.] 



SPECIFIC HEAT. 



477 



the temperature of a body 1, and the quantity neces- 

 sary to raise the temperature of the same weight of 

 water, is called the specific heat of the body. 



For example, the specific heat of water being 1, 

 that of iron is -11379, lead -0314, brass -09391, mer- 

 cury -03332, ether -5157. 



Water has the greatest thermal capacity, hence 

 its value for heating purposes. 



The differences in the specific heat of different 

 substances explains how two bodies at the same tem- 

 perature will give out different amounts of heat. 



The average specific heat of the animal 

 body is given as about 0'83 (water being 1). 



The following table gives the specific heat of 

 various animal substances : 



Blood (human) 

 Arterial blood 

 Venous blood 

 Defibrinated blood 

 Muscle (striated) 

 Compact bone 

 Spongy bone 

 Adipose tissue 



Muscle of oxen 

 Cow's milk 



1-020 

 1-031 

 0-892 

 0-927 

 0-825 

 0300 

 0-710 

 0-712 



0-787 

 0-992 



Calorimetry. The determination of latent and 

 specific heat implies the measurement of quantities of 

 heat. This is called calorimetry ', and the instrument 

 by means of which the measurement is made is called 

 a calorimeter. It is obvious that a standard unit of 

 heat is required. This we have already seen (page 

 454) to be the quantity of heat necessary to raise 

 the temperature of unit mass of water from to 

 1 C. , and is called the caloric. The quantity of 

 heat given out by a body may, therefore, be measured 

 by the quantity of water whose temperature it will raise 



