228 Transactions of the London Horticultural Society. 



same as above de- 

 scribed ; but, in lieu 

 of the bed of broken 

 stones, &c, bricks 

 are here placed edge- 

 wise, one over the 

 other, four deep, ar- 

 ranged in the same 

 manner as for burn- 

 ing in a kiln : over 

 these bricks is laid 

 a flat cover, jointed 

 close without mor- 

 tar; and, on this, 

 the mould contain- 

 ing the plants." 



For Aquatic Plants. 

 — Fig. 29. " shows 

 a mode of warming a 

 cistern or reservoir 

 of water for the preservation of aquatic plants, as erected at Mr. Miller's 

 nursery at Clifton, in front of one of the green-houses, and having a glass 

 29 roof. Steam is ad- 



mitted by a pipe, 

 three quarters of an 

 inch in diameter, 

 having perforations 

 of about one tenth 

 of an inch at each foot in length ; the extremity of the pipe being closed, the 

 steam issues through the small apertures, filling the whole internal area of the 

 large pipe in which it is enclosed, and imparting an equable temperature to the 

 whole extent of surface. This effect cannot be obtained by applying steam 

 in the common way, when but a small increase of temperature is required ; 

 as the water immediately in contact with the pipe where the steam is admitted 

 would absorb nearly the whole of its heat, till it arrived at a temperature far 

 beyond what could be allowed in a case of this kind. The dimensions of the 

 reservoir alluded to are about 3ft. by 3 ft. 6 in., and 20 ft. long. The external 

 pipe is 4- in. inside in diameter ; and the condensed water from it is taken away 

 by a small inverted siphon at the farther end." 



Heating the Atmosphere of Conservatories, Hot-houses, §c. — Figs, 30, 31-, 

 and 32. "represent a mode of heating water in pipes by the agency of steam. 



31 



