184 



HEATING AS APPLIED IN HORTICULTURE. 



enters it near the bottom at the right- 

 hand side. It must, however, be care- 

 fully borne in mind, that no part of the 

 flow-pipe should dip to a lower level 

 than that of the point from whence it 

 started, nor the return-pipe dip deeper 

 than the part where it enters the boiler. 

 An air-tap, about the size of an ordinary 

 quill, should be fixed in the flow-pipe at 

 its highest point, for the escape of air, 

 which, if allowed to exist in the pipes, 

 would completely arrest the circulation of 

 the water. The want of this precaution 

 has been the cause of many an excellent 

 hot-water apparatus being condemned, 

 which otherwise would have wrought 

 admirably. Such an arrangement as 

 this will in no way interfere with domes- 

 tic arrangements, as a stopcock can be 

 placed on both the flow and return pipes, 

 either close to the boiler within or close 

 to the wall without, as may be most con- 

 venient. Such a magazine of heat as a 

 boiler so constructed will add greatly 

 to the heat of the room in which it is 

 placed, and that without requiring any 

 additional fuel. It is for many reasons 

 desirable that the top of kitchen-range 

 boilers should be open, at least so far so 

 as to render their being occasionally 

 cleaned out more convenient. In such 

 cases the pipes in the pits must be upon 

 an exact level with the top of the boiler ; 

 but where such boilers have fixed tops, 

 the pipes may be at any height above 

 them, as the heated water will ascend to 

 them, and the water, when deprived of its 

 heat, will return to the boiler upon the 

 common principle of hydraulics. The 

 boiler need not, however, be the whole 

 depth of the fire-grate, but only reach as 

 far as the bottom of the fire-bed, as 

 marked by the dotted line in our figure. 



A greenhouse or conservatory of con- 

 siderable size, attached to the house, may 

 be heated by the same means, and even 

 if 20 or 30 feet distant ; as may also pits- 

 'at 100 feet from the boiler, provided 

 care be taken to place the pipe which 

 connects the boiler with the radiating 

 pipes in the greenhouse or pits in a non- 

 heat-conducting or heat-abstracting me- 

 dium. This is by no means a new 

 mode of heating greenhouses attached to 

 dwelling-houses, as it was recommended 

 twenty years ago by the late Mr Ander- 

 son, curator of the Chelsea Botanical 



Gardens. We are only surprised that so 

 simple and economical a mode should 

 have been so long known, and seemingly 

 so little used. 



General remarks on heating by hot water. 

 — After upwards of twenty-five years' 

 experimenting upon heating with hot 

 water, there appears to us to be only 

 three distinct principles — namely, Atkin- 

 son's horizontal, Kewley's siphon, and 

 Eckstein and Busby's rotary float cir- 

 culator. The rest, although differing in 

 form of boiler, and position and extent 

 of radiating surface, present really no 

 new feature in their principles. 



Since the introduction of tank-heating, 

 the hotwater-pipe system is undergoing a 

 species of condemnation by some, little 

 short of that pronounced against the old 

 flues. Their cry is, that the heat it pro- 

 duces is dry and parching, whereas that 

 secured by the other is moist, and all 

 that we can desire. Now, it ought to be 

 kept in mind that heat produced by com- 

 bustion is exactly the same, whether pro- 

 duced by a smoke flue, a hot-water pipe, 

 or a gutter or tank, excepting that in 

 the latter case it is accompanied with a 

 considerable degree of humidity if the 

 gutter is open at top. Heat produced 

 by fermenting materials, such as stable 

 manure, is quite a different thing ; and, 

 could it be as economically applied, 

 which it cannot, and its heat as readily 

 commanded as that by the use of com- 

 bustible materials, it should never be 

 abandoned until we discover means of 

 producing the same gaseous fertilising 

 constituents which it contains. Water 

 from tanks produces pure steam without 

 much fertilising property; and, unless 

 this is properly provided against, causes 

 too humid an atmosphere. Hot-water 

 pipes produce no steam as they are 

 generally applied, and hence the heat 

 from them is much the same as that 

 from smoke flues, with this advantage, 

 that they are not so easily overheated, 

 give out no injurious gases, and retain 

 their heat much longer, while they do not 

 absorb so much of the humidity of the air 

 as smoke flues do. But, either with smoke 

 flues or hot-water pipes, the atmosphere of 

 a house or pit may be kept as humid as 

 there is any necessity for. Flanges have 

 been cast on the top of hot-water pipes, 

 and saddle-shaped trays have been placed 



