HOT 



307 



HOT 



ground very small, it attains a sufficient left undisturbed, continue at a temper- 

 warmth in a fortnight for the insertion atureof 64° for many months, he seems 

 of the plants, and will continue in heat , to intimate as long as fourteen. This 



for two or three months ; the larger the 

 fragments of the bark are, the longer 

 time it requires to ferment, but in an 

 equal proportion it attains a higher 

 temperature and preserves it much 

 longer; a middle sized bark is, there- , 



material is, however, to be had in very 

 few districts. Grass and other green 

 herbage, and even wetted straw mixed 

 with coal-ashes, have been used on an 

 emergency with success. Instead of 

 forming hot-beds with open sides, as has 



fore, in general to be preferred; and been hitherto described, J)^7s of brick- 

 added to the above consideration, it is work and other materials, are very 

 to be remarked that, when made of generally constructed for containing 



large fragments, violent and sudden 

 excesses often arise, even after the bed 

 has been constructed two or three 

 months : on the contrary, if very small, 

 the fermentation soon passes oft". 



When the crops are removed, and 

 the heat declines, if well stirred, and a 

 load or two of fresh bark mixed with it, 

 the bed will acquire and continue in 

 heat for an equal further lapse of time : 

 this may be repeated throughout the 

 year as often as the heat is found to 

 decline. But it is necessary every 

 autumn, entirely or nearly so, to re- 

 construct the bed with fresh bark; for 

 when the old is far advanced towards 

 putrefaction, it will no longer generate 

 heat. 



the fermenting mass. It may be laid 

 down as a fundamental principle, that 

 in applying heat, it should always be 

 brought to the bottom of the body to 

 be heated. 



Mr. Flanagan only allows the heat of 

 fermenting dung to be employed, the 

 steam being prevented entering the 

 frame. One advantage arising from this 

 he states to be, that fresh made dung 

 may be employed, and consequently the 

 loss sustained by any preparation is 

 prevented. If, however, it be a fact 

 that the steam of dung is rather bene- 

 ficial than otherwise, fresh fermenting 

 dung can be used without any detriment 

 that I am aware of in other pits of 

 which we have plans. Mr. F. describes 



The leaves of the oak and sweet his pitas follows: — " It is four feet deep 

 chestnut, and doubtless of many other i within, the lowest ten inches of solid 

 trees, answer for hot-beds as well or brickwork sunk in the earth; the re- 

 even better than tanner's bark, since mainder is a flue three inches wide in 

 they will continue to afford a moderate the clear, carried entirely round the pit, 

 heat for nearly twelve months without i the inner wall of which, forming the 

 any addition or stirring. They are to ' " 

 be collected as they fall in autumn, and 

 carried to some situation, or be so hur- 

 dled in, that they may be preserved 

 from scattering by the winds; the heap 

 should be si.x or seven feet thick, trod 

 firmly down, and moderately watered 

 if dry. In a few days, a very powerfu" 



sides of the pit, is four inch work, well 

 bedded in mortar, and pointed to pre- 

 vent the steam penetrating ; the outer 

 wall of the flue is also four inch, but 

 open work to admit the steam, and that 

 of dung coatings into the flue, the top 

 of which is rendered tight by a covering 

 of tiles, &c. The frame rests on the 



heat is produced, and in five or six i external wall of the flue. The cavity 

 weeks will have become so regular, ■ of the pit, which is kept dry by means 

 that it may be broken up and the beds of drains, is nine feet two inches long, 

 constructed with its materials, water j two feet eight inches wide, and four 

 being again employed if dryness ap- [ feet deep. It is filled with broken 

 pears, and they must be well trod down bricks to within eighteen inches of the 

 as before. There are many other sub- top, then a foot of short cold dung, six 

 stances that generate heat during fer- inches of very rotten dung trod down 

 mentation; there is perhaps no vegeta- j so as to admit half an inch depth of 

 ble substance that does not; even a I coal-ashes, for preventing the intrusion 

 heap of dry sticks acquires a strong of any worms that may be in the dung, 

 accession of temperature if moistened, j completes the structure." 



Mr. Burnet recommends the trial of the i The accompanying sketch and refcr- 

 refuse matter thrown oft" in dressing ences will fully explain the plan of Mr. 

 flax, for constructing hot-beds : this re- | West. D D, chamber in which the dung 

 fuse he says he has observed, when is placed, three and a half feet deep, 



