89 



round the outside of the platform, to the width of 

 3 inches, tc admit of a free circulation of heated air 

 and humidity just when considered necessary, by 

 turning up the narrow ventilators, which should be 

 placed over the outside cavity, and made also with 

 galvanised iron, and hung upon hinges in about three 

 lengths at the front or back of each compartment. 

 The depth of the platform need not be more than 16 

 or 18 inches ; if the latter, it would admit of 3 inches 

 of rough charred materials placed upon the bottom ; 

 here the fruiting plants could either be turned out in 

 a proper, or what may be considered a suitable pre- 

 paration, or plunged in their pots. Possibly some 

 practical men may imagine, were they to turn out 

 plants into such a structure, they would like a greater 

 depth of soil ; but Mr. Barnes considers such a 

 depth of suitable soil and drainage is quite sufficient, 

 as it would readily allow a free circulation of air, 

 water, and humidity, and would not be so likely to 

 become soured as a greater depth would ; and it is 

 certainly a sufficient depth for placing the potted 

 plants in, which should be entirely filled up between 

 with charred vegetable matters in a rough rubbly 

 condition. 



A four-inch flow and return hot water pipe should 

 pass along the whole length at front of the pit; and the 

 best known method adopted for giving air and cover- 

 ing, keeping economy as well as efficiency in view. 



