■ HALL AND AYRES. — HEAT CONDUCTION IN IRON. 297 



cause made the later values at a given temperature about one per cent 

 greater than they would have been had they been obtained at the same 

 temperature in May or June. In these earlier months sets of observa- 

 tions were made at various temperatures from near 20° to near 75°. In 

 July and August sets near 28° were intermingled with sets near 57°. It 

 is possible, therefore, to make for each period an independent determina- 

 tion of the temperature coefficient of K. 



We have from the May and June division : — 



56°.8 0.1475 0.1449 0.1462 



