34: 



OPEN AIR GKAPE CULTURE. 



by plentiful addition of lime and any black mold or 

 charcoal. 



Maximum Temperatures of the various Earths 

 Exposed to the 8un. By Schubler. 



Table of Retention of Heat. By Becquerel. 



From these tables 'it will be seen that black mold 

 receives or absorbs heat most rapidly, but parts with 

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



