v RIVERSIDE LETTERS 35 



son, however, who had studied physics, 

 gave me the proper explanation ; it is simple 

 enough, just as the explanation of a good 

 conjuring trick always is ; it is owing to the 

 fact that glass allows luminous heat to pass 

 through it readily, but is a bad conductor of 

 non-luminous heat ; so the heat gets caught 

 inside the house in a sort of trap, the light 

 carrying the heat through the glass and there 

 leaving it to shift for itself to get out again ; 

 thus it becomes stored, being continually 

 accumulated as long as the sun shines. 



I do not attempt very much in my glass- 

 house ; the back wall is devoted to my fig- 

 tree, and in lieu of the usual stand for pots in 

 the front I have a solid bed of rich soil three 

 feet deep, in which I can plant anything 

 I like. There is a large tank for rain water 

 in one corner, and some shelves to carry pots 

 close up to the glass. 



My fig-tree is a great success, it now 

 nearly fills the back wall, and I have to 

 prune it every year, cutting out the old wood 



D 2 



