118 



Description of a Glass Case 



Dec. 28. I have filled the case for three quarters of its depth 

 with soil, have set on it several hundred bulbs (from snowdrops 

 up to hyacinths, &c.), and have filled all the interstices between 

 the bulbs with green moss. I have given only two gallons of 

 vv^ater (Mr, Ellis's appeared to me rather moist), and have closed 

 all up : some time must elapse before any judgement can be 

 formed from the appearance of the vegetation ; but already the 

 circulation of the water is beautifully shown by the condensation 

 on the glass plates, and the trickling down of the miniature rain. 

 In the morning the glass plate which is nearest to and pai-allel 

 with the window-sash, and which has consequently been losing 

 most heat, exhibits both the condensation and running down of 

 the water in a remarkable degree ; while the inner plate, receiving 

 heat from the air of the room, or by radiation from the objects 

 near it, remains quite clear. I have planted a few bulbs in 

 another receptacle (and in the same way as to soil and moss), by 

 keeping which in the same room, but exposed to the air in the 

 usual way, some judgment may be formed of the relative ad- 

 vantages of these different modes of raising such plants. 



In the sketches [Jigs. \^. to 18.) I have not represented the out- 

 lets for superfluous water which are much in the same way as Mr. 



Ellis's above referred to. Neither have I shown the contrivance 

 for maintaining the identity of the air first enclosed in the case ; 

 it would have confused the drawing, and will be easily understood 

 from description. The size of the plates of the sides and top of 



