34? 



Wardian Cases. 



require for their growth? Shade and moisture : upon the former, in a great 

 degree, depends the latter. A northern or eastern aspect, where the morn- 

 ing sun reaches the case, we think is best. As regards moisture, we have 

 the principle of self-support in an air-tight case ; for, if you allow the sun to 

 reach the case for an hour or so in the morning, you will find that the 

 moisture needful for the growth of your ferns is extracted from the earth ; 

 and, when evening comes, this same moisture will condense and fall. Each 

 da}'', this process of extraction and condensation takes place, and your plants 

 flourish under a necessary and sufficient moisture. Now, this being the 

 kind of air we want, we must not, of course, ventilate our case, and allow 



Octagonal Wardian Case. 



it to escape ; otherwise the dry air of our rooms would enter, and a watering 

 of the case become a necessity. This at once upsets, all the benefits de- 

 rived from these cases. The temperature, also, must be much more even in 

 an air-tight case than in a ventilated one, where the constant opening and 

 shutting of doors and windows would affect it. If we have no watering to 

 do, we have no water to run off, and consequently require no drainage in 

 the bottom of our case. Now, in this air-tight principle we get at the secret 



