THE WARDIAN CASE. 243 



hemisphere of glass, large enough to cover the smaller 

 dish, and to rest its rim on the water of the larger. 

 The water prevents the admission of air, and the only 

 care is to see that it never entirely evaporates from 

 the outer dish. Your case is done; and with a little 

 ventilation, your plants will grow with a vigor and 

 freshness unknown to you before. These common cases 

 may be made of any size, and any clear glass will do as 

 a cover. The lower dishes may be common stone ware, 

 and the cover one of the glasses used by confection- 

 ers to cover cake, or what is better, a common plain or 

 tubulated receiver, which may be procured at any glass 

 house, or of any dealer in chemical ware. 



