Forcing-Pit heated by hot Water. \ 39 



pierced zinc ; one movable, that the gardener may cleanse it if 

 clogged, and the other fixed. 



The advantages of these conical boilers are no longer matter 

 of speculation or experiment. My own, and several others con- 

 structed under my instructions, have been in use between three 

 and four years. Of the iron ones very many have been erected 

 in the course of the last eighteen months, and are highly ap- 

 proved ; although few of them possess all the advantages which 

 experience has since combined in the form now described. They 

 are peculiai'ly adapted for those purposes where perpetual heat is 

 required, for plant stoves, pineries, and forcing-frames ; also for 

 small propagating-houses, or preserving-pits. To pits in gene- 

 ral, from their small size, and from the small expense incurred 

 in setting them, a recommendation not heretofore noticed, they 

 are peculiarly applicable, and have been extensively applied. 

 That employed in the half-hardy pit in the Horticultural So- 

 ciety's Garden, at Chiswick, is a fair specimen of their applica- 

 tion, though that boiler is capable of doing considerably more 

 work than is now allotted to it.* 



Sevenoaks, February 7. 1840. 



Art. XIII. Description of a Forcing-Pit heated by hot Water. 

 By John Rogers, Jun. 



The cultivation of melons, cucumbers, and pines by steam, 

 instead of by dung or tan, has long been successfully practised in 

 those establishments, which are of sufficient magnitude to admit 

 of the introduction of steam apparatus. But steam-boilers exist 

 in comparatively few gardens, and in many places where they 

 were formerly employed they have given place to the more eco- 

 nomical and commodious contrivance of hot water. It has 

 become, therefore, an important consideration, to devise the best 

 mode of employing this last agent to supply at once top and 

 bottom heat, combined with that degree of moisture requisite in 

 early forcing ; and, as yet, such a contrivance seems to be a de- 

 sideratum in horticulture. 



The annexed sketches are the plan and section of a pit, by 

 which it is proposed to attain these objects in the most efficient 

 and economical manner, and at the same time to secure certain 

 other effects which may by some persons be deemed of con- 



* I annex, according to your request, the prices of the conical boilers, 

 with which Mr. Shewin has furnished me: — 10-inch, 4/. 10s.; 13-inch, Ql, ; 

 15-inch, 11. IO5. The fittings, comprising doors, dampers, &c., all things, in 

 short, peculiar to the apparatus as above described, vary from about 1/. 5s. to 

 1/. 13s,, according to the size, and the articles required. The appendages for 

 steaming the house are not included in the above. 



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