34 



OPEN AIR GKAPE CULTUKE. 



by plentiful addition of lime and imy black mold or 

 charcoal. 



Maximum TemyeraiuTes of the variGics Eartlis 

 Exposed to the Sun. By Schubler. 



Tcible of Retention of Heat. By Becqiievel. 



Erom these tables it will be seen that black mold 

 receives or absorbs heat most rapidly, but parts vrith 

 it in the shortest space of time also, and that for 



