January 15, 1867. ] 



JOURNAL OP HORTICULTUBE AND COTTAGE GARDENER. 



41 



WEEKLY CALENDAR. 



MODES OF HEATING. 



EAT. that subtle, invisible 

 agent, exercises an intluence 

 on both animal and vege- 

 table life beyond aU ealcu- 

 lation. In the case of ani- 

 mals its presence in proper 

 amount sustains life, and its absence causes death : wliile 

 in the vegetable world it is scarcely' of less importance, as 

 growth is most rapid where it abounds, and the plants 

 there attain gi'ander dimensions than in colder climates. 

 My remarks must, however, be restricted to tlie artificial 

 means for the attainment of desired temperatures, the 

 object being the suppljdng beat to a given space, wliilst 

 wasting as little as possible of the materials emploj-ed to 

 impart that heat. Combustion of coal or other fuel is the 

 source of such heat, although fermenting materials also 

 supply it. and recourse to the latter mode of heating is not 

 likely to be ever abandoned. I will, however, first advert 

 to the mode of supplying heat by the combustion of fuel. 



Let us now see how fire heat can be applied in the 

 most economical manner. Assuming a given quantity of 

 fuel to aftbrd a certain amount of heat, in wliich way can 

 that beat be used for the purpose requii-ed with the least 

 possible waste '.' for, that a considerable amount of heat is 

 wasted, even in the best constructed apparatus, cannot be 

 denied. I have on former occasions argued tliat one of 

 the best examples of fire being applied to an object from 

 which it is again abstracted witli the least loss, is aflbrded 

 by an ordinary brick oven, where the combustion takes 

 place inside, and the heated sides, bottom, and roof are 

 all required for the purpose of baking bread ; externally, I 

 believe, but little heat escapes, and the amount of that 

 which goes up the chimney is less than in many heated 

 structures. This economy, however, is attained by the 

 fire acting directly in accomplisliing the object in view, 

 and not by its heat behig communicated through another 

 medium, as in the case of plant-houses ; for in the latter it 

 is the atmosphere that requh-es warming, and it is diflicult 

 to apply fire heat b}- any \-ery direct means without at the 

 same time imparting to the air some properties injurious 

 to vegetation. Heat, however, has sometimes been applied 

 in a manner more dii'ect than is often thought practicable, 

 but the results have not generally been satisfactory. A 

 mode of doing so, however, which came to my knowledge 

 many years ago is worth repeating, as it was one of tlie 

 most remarkable cases of fire du'cctly supplying bottom 

 heat that I am acquainted with. It was as follows : — 



In the coal districts of the north, before the demand was 

 so great for small coals for steam-engines .and other pur- 

 poses, large quantities were thrown away as waste at the 

 mouth of the pit, and being ignited, and augmented daily 



N ). 303. -Vol. XII., New Seeies 



by several tons of additional fuel, an immense fiery lieap 

 was always burning at the mouth of tlie pit. I believe 

 some of the heaps covered an acre of ground, and a red 

 and lurid fl;i,me might be seen miles off on dark evenings. 

 Some of the heaps were ^!0 or 30 feet deep, the outer edge 

 sloping oft' to meet the natural ground, and it was on the 

 outer edge of one of these fiery heaps that some one at- 

 tempted the out-door forcing of vegetables. As the fire 

 had in a certain measure left the corner he intended to 

 operate upon, although the aslies were still hot below, the 

 operator determined to cover a portion of the heap with 

 earth, and plant Potatoes, wliich he watered and attended to 

 in the proper manner : and as at a local horticultural show 

 prizes were offered for the best disli of Potatoes grown in the 

 open air, liis crop was deemed eligible, and he easily car- 

 ried olf the first prize. Here. then, was a case of the direct 

 action of fire underneath the object forwarded. Although 

 it is not an example which it would be prudent to imitate, 

 some modification of it might be attempted ; and the mode 

 adopted at Leeds Castle by C. W. Martin, Esq., M.IV, as 

 detailed in the last Volume, is one of the methods iu which 

 heat from beneath may be applied. This plan, as vnll be 

 remembered, was by haWng an imdergi'ound chamber, at 

 one corner or side of which a fire was kept, wliich, i)laying 

 all over the chamber, was not allowed to ascend the chim- 

 ney until all the lieat had been expended, and the little 

 smoke uuconsumed rendered comparatively cool. This 

 Mr. Martin calls the bypooaust mode of heating, and its 

 merits are its simplicity and the ease with wliich the heat 

 acts on the part where it is most needed, v.-hich is, of course, 

 tiie roof. 



In this immediate district, where large quantities of Hops 

 are gro\vn, the drying them by fire heat has called forth 

 many modes of applying it, from some of which hints 

 may, perhaps, be gleaned. Hops are more frequently 

 gathered wet than dry, and even if they were always dry 

 they would have to undergo a process of fire-drying in order 

 that they might be kept ■n^thout moulding, for the moisture 

 in the stalks and bases of the scales has to be driven out 

 by heat, and tliis is an operation involving a large expen- 

 diture of fuel. Such, too. iu the general construction of 

 Hop-kilns is of a rather expensive kind, ordinary wood 

 and coal fires being sekbim used, although in one of the 

 cases where this is done the plan so closely resembles 

 what is called the Polmaise system that it is worth de- 

 scribing here. I may in the first place remark that Hops 

 are generally dried on a floor up-stairs ; the floor, instead 

 of being of the ordinary description, is composed of a hair- 

 cloth spread over a latticework of timber not likely to 

 ignite with the heat, Poplar wood being esteemed the best. 

 Very often the k-iln is circular, and from 12 to 18 feet in 

 diameter ; the chamber, where the fire is bmuing, is seldom 

 less than I'i feet, and more fi-equently l.'i or l.s feet, high 

 to the drying floor, and the roof tapers up in a conical 

 manner from a little way above tliis floor to the apex, where ; 

 an opening, o feet iu diameter, is left for the steam to 

 escape. Tliis opening is protected from rain by a cowl' 

 moving with the wind, and every care is taken to insm-e 

 the steam passing off quickly. The interior is plastered 

 So. 955.-VOL. XXXVII., Old Series. 



