Mat 1901.] BOTANICAL SOCIETY OF EDINBURGH 



75 



months is but 0-093, and the growth in the six growing 

 months is l"39o ; and as growth in the sleeping season is 

 complicated with occasional diminutions of girth or 

 shrinkage, probably demanding a separate investigation, 

 it may be best now to attend to the growing season of 

 deciduous trees. 



The low maximum thermometer is no doubt attributable 

 to the cooling of the air by rain ; but how does a warm 

 minimum thermometer in the six growing months conduce 

 to good growth ? Eain, as is probably beyond dispute, 

 is the prime factor of growth, and rain certainly tends 

 to cool the air in the growing season both by day and 

 night, though in the sleeping season the thermometer reads 

 higher during rain than during frosts, which accounts for 

 the high minimum thermometer accompanying good growth 

 of evergreens in the winter months. 



Table I. 



