On the Expansion of some Solid Bodies by Heat. 269 

 where J) t expresses the specific gravity of the substance referred 



to water of the temperature t° as unit. Further, is ^ =D =the 



specific gravity of the solid substance at t° referred to water at 

 (ft as unit, where V t expresses the volume which 1 volume of water 

 at 0° assumes on being heated to t°. 



Supposing that for two temperatures t and t', the former of 

 which is lower than the latter, the specific gravities D and D ' 

 respectively be found, then is the cubic expansion of the body 



t'-t\D ' V 



