32 



HEAT. 

 (38) MOLECULAR DATA FOR GASES. 



(39) THERMAL CONDUCTIVITIES. 



The number of gram-degrees of heat which pass in a second 

 through a plate of the substance 1 cm. square and 1 cm. thick, the 

 opposite faces being kept at temperatures differing by 1 C. 



Water '002 



Fir across fibres '00026 



Fir along fibres '00047 



Oak across fibres '00059 



Cork '000029 



Writing-paper sized.. '00019 



Grey paper unsized... '000094 



Calico (new) '000139 



Carded wool '000122 



Cottonwool ... '000111 



Eiderdown -000108 



(40) MISCELLANEOUS DATA IN HEAT. 



A calorie (kilog. water through 1 C.) in Ibs. heated 



through 1 F 3'968 



A British unit of heat in calories '252 



Mechanical equivalent of British unit of heat in 



foot-lbs 775-47 



Mechanical equivalent of a calorie in kilog. -metres. . . 425 '454 

 Mechanical equivalent of a water-gram-degree in ergs 4 '175 x 10 7 

 Mass of 1 ccm. of aqueous vapour at C. and 760 



mm. in grams '000806 



