554 MR A. CRICHTON MITCHELL ON THE THERMAL CONDUCTIVITY 



The third column in the table shows the quotient resulting from the division of 

 each of the ratios by the first. 





Rate of Cooling. 







Temperature 

 Excess. 





Ratio of 

 these Rates. 



Ratios 



1-054. 







10 



Copper (Crown). 



Iron. 







116 



11 



1054 



10 



20 



•28 



•26 



1077 



1021 



40 



•66 



•61 



1082 



1026 



60 



104 



10 



104 



•987 



SO 



1466 



1-405 



1043 



•989 



100 



1-927 



1-83 



1053 



•999 



120 



239 



2-28 



1048 



•994 



140 



2-87 



2-77 



1036 



•983 



160 



338 



3-28 



103 



•979 



180 



3-98 



3815 



1044 



•989 



200 



4-66 



4-4 



1059 



1005 



220 



533 



5 03 



1059 



1005 



240 



5-89 



5-74 



1026 



•971 



III. Final Results. 



The units in terms of which the conductivity is given are those of foot, 

 pound, minute ; while the thermometric scale is, of course, Centigrade. 



Iron. 

 (Ordinary Form of Experiment.) 



x, ill feet. 



V. 



dv 

 dx 



Area of Statical 



Curve of Cooling 



to the Succeeding 



Value of x. 



Area of Statical 



Curve of Cooling 



beyond x. 



Area corrected for 



change of Spec. 



Heat. 



00 



247-2 



301 



1352 



43669 



53049 



025 



1721 



19-54 



8-703 



30149 



34-598 



05 



12525 



1322 



5-96 



2T446 



23885 



075 



923 



92 



7-2 



15486 



16-877 



T25 



520 



4-79 



3-74 



8-286 



8-785 



1-75 



3035 



292 



1-92 



50 



538 



225 



182 



1-52 



1-056 



2626 



2-708 



275 



1115 



10 



•949 



157 



1-612 



375 



43 





•381 







475 



1-85 





172 







5-75 



07 





* -062 







Hence, thermometric conductivity of Iron. 



(1) From areas uncorrected for sp. ht. change. 



0°. 100°. 200°. 300°. 



•0125 -01156 -01062 -00968 



(2) From areas corrected for sp. ht. change. 



•0129 -01266 -01243 0122 



* The last number in each of these columns gives the whole area of that part of the curve beyond 

 the corresponding value of x. 



