The Conductivity of Heat Insulators. 



2S7 



agreement between these values shows that no appreciable drop occurs 

 at the separating surfaces. 



These points being settled, the various substances named above were 



Fig. 2. 



Material. 



Tempera- 

 ture 



differences. 



Watts 

 supplied. 



Watts 

 per 1° C. 



c. 





19 2 



25 -0 



1-30 



-000200 





19-8 



31 -7 



1-58 



-000242 



Pine shavings 



19 -5 



20-8 



1-06 



-000162 



Brown paper (crumpled up) . . 



20-2 



22 -0 



1-09 



0-000167 





25 -8 



24-5 



0-95 



0-000145 



Hair felt in two sheets, % inch 



i . , i ; . yi J i 











27 '2 



18 -9 



0-69 



-000106 





14 9 



29-0 



1-94 



-000297 





27-8 



27 2 



0-98 



-000150 





8-0 



39-0 



4-85 



-000740 





14-0 



13 -7 



0-98 



-000150 





23 -2 



21-8 



0-94 



-000144 





27-8 



22 -3 



0-80 



-000122 





24 -7 



24-5 



0-99 



-000151 



