HOT 



306 



HOT 



mass, is an efficient precaution, and is ' are frosty for the admission of air. A 

 much preferable to a similarly placed , complete remedy for all these difficul- 

 layer of turf, which interrupts too much I ties is afforded by a plan, which suc- 

 the full benefit of the heat. A plan re- 1 ceeds on the principle that warm air 

 commended by Bradley is well worthy' ascends, and simply consists of a pipe 

 of notice. A woven hurdle somewhat passed through the body of the bed, 

 larger than the frame being placed , and one end communicating with the 

 upon the dung, on this its woodwork i exterior air, the other opening into the 

 can rest, and the earth is laid within | frame, at one of the top corners of 

 it, ihus the whole can be moved to- j which an aperture must be made ; the 

 gether without disturbance. This would ' heated air of the frame will constantly 

 especially he of advantage when bark I be issuing from this aperture, and its 

 is employed, which requires occasional place supplied by that which rises 

 stirring to renew its heat in case of! through the pipe. A pipe of lead may 

 emergency, when time cannot be al- ' be used, about two or three inches in 



lowed for the bed becoming regular in 

 its heat before the plants are inserted 



diameter, bent nearly at a right angle, 

 and each limb being three feet long, 



Besides these precautions, vacancies I one of these to be placed horizontally, 

 should be left in the mould, and holes I as the bed is forming, with its mouth 



bored with a thick pole into the bed, 

 which must be filled up with hay or 

 dung when the danger is passed. 



For ascertaining the internal temper- 

 ature of the bed, the thermometer is 

 the only certain guide, as it also is for 

 judging of the temperature of the air 

 within the frame; the mode of intro- 

 ducing it into the body of the bed, is to 

 have the thermometer inclosed in a 

 wooden case of the size and form of an 



extending in the open air, that of the 

 other opening into the frame ; a cap 

 should be fitted to the first, and by a 

 slit on its under side, the quantity of 

 air admitted can be regulated. 



Although stable manure is generally 

 employed for the constructing of hot- 

 beds, yet there are several other vege- 

 table matters that are also in use for 

 the same purpose. Tanner's bark, 

 from its long continuance and regu- 



ordinary dibble, which is to be lined i larity of heat, is much to be preferred, 

 with baize and fitted with a cap ofj especially for very tender exotics. In 

 tliinned iron to exclude the exterior | many situations it can be obtained at a 

 temperature. The end which enters cheaper rate than stable dung ; it should 

 the earth is shod with perforated cop- be employed when fresh drawn from 

 per. In conjunction with the ther- \ the vats, or at most when a fortnight or 

 mometer, trying sticks may be employ- [ three weeks old ; it must lay in a heap 

 ed for occasional observation; these | for six or eight days to allow the escape 

 are smooth laths of wood, about two 1 of the superfluous moisture : in summer 

 feet in length, thrust into different parts this is not of such material consequence. 



of the bed, which, being drawn out and 

 grasped quickly, afford a rough esti- 

 mate of the heat of the bed. 



The small extent of the frame, and 

 the rapid deterioration of the air within 

 it by the plants, render its frequent re- 

 newal necessary. To effect this, the 

 common practice is to raise the glasses 

 in proportionate heights according to 

 the state of the air; and to prevent any 

 injury arising when necessarily admitted 

 during inclement weather, mats are 

 hung over the opening ; but notwith 



as an excess of wet is, at that season, 

 not so liable to prevent fermentation. 



If the ground is dry, a pit three feet 

 deep may be dug, and is better lined 

 with slates, boards, or brickwork, but 

 whatever may be the nature of the soil, 

 it is best to form this case or bin of a 

 similar height upon the surface. With- 

 out some support the tan will not form 

 a solid bed, and if mould becomes 

 mixed with it, the fermentation is re- 

 tarded or entirely prevented. The 

 breadth must not be less than five or 



standing these precautions, the supply | six feet, or of a length shorter than ten 

 of air can seldom be regular; hence, ! or twelve, otherwise the heat will not 

 and from sudden chills, the plants are i be lasting. When the bark is laid, it 

 often checked, and sometimes essen- [ must be gently settled with the fork, 

 tially injured. It may be remarked but never trodden upon ; for if violently 

 here, that raw foggy days, if anything, I compressed, it loses the power of fer- 

 are more unfavourable than those that I menting ; if the bark is fresh and not 



