460 



MELLONI ON THE NOCTURNAL COOLING OF BODIES. 



Hence the differences referred to the minimum value (that of 

 Aj, that is to sajj to the mean indication of this instrument, 

 were — 



l7°-796-l7°-764 = 0°'032 for B, 

 l7°-822-l7°-764 = 0°-058 for C. 

 Afterwards the metallic plates which covered the recipient vessels 

 were removed ; and at 9*^ 15™ the indications of the thermometers 

 were again noted down every three minutes. The following are 

 the results of these latter observations. 



Taking the differences between B, C and A, wc have — 



14°-15S-l4°-13 = 0°-028 for B, 

 14°-196-14°'13 = 0°-066 for C; 



which differences are sensibly equal to the preceding, within the 

 limits of errors which may be incurred in appreciating fractions 

 less than tenths of a degree which were marked on the scale, 

 and yet left a considerable interv^al between the divisions. 



The means of these two pairs of differences are 0*030 and 

 0*062 ; it may then be admitted that, between fourteen and 

 eighteen degrees, and temperatures but little differing from these 



