HEATING BY HOT-WATER PIPES. 



175 



It may be asked, why republish this 

 system, which has been so generally con- 

 demned 1 We do so because it may act 

 as a beacon to warn future experimen- 

 talists, and also on account of the judi- 

 cious reasoning brought out in testing 

 its merits. The knowledge of failure is 

 often as useful to us as that of success. 



Goldridge and Sons' heating apparatus. — 

 The boiler used by this firm is in the 

 form of a long cylinder, about 6 feet 6 

 inches in height, by 18 inches diameter; 

 it has a spiral flue from bottom to top, in 

 which are sundry flues for cleaning out 

 the soot. A double valve is placed at 

 each extremity of the pipe, for the purpose 

 of controlling the heat, or of stopping the 

 circulation when required ; there is also 

 an open cylinder, with a floating index, to 

 facilitate the escape of air, and to show 

 the elevation of the water in the boiler. 

 When the machine is set to work, the 

 valves are shut until the water boils ; the 

 pipes are then opened, the immense per- 

 pendicular column of rarefied particles is 

 propelled forward with inconceivable rapi- 

 dity, and the whole line of pipe attains a 

 high degree of temperature in a few 

 minutes, and in less than an hour arrives 

 at its maximum of heat. The action is 

 so powerful that the atmosphere in the 

 building is speedily warmed to any tem- 

 perature required : should it be too hot, 

 the circulation can be instantly stopped 

 by means of the valves, and the tempera- 

 ture lowered to any point required. The 

 superior advantage of this apparatus 

 appears to consist chiefly in the boiler. 

 It is customary with many to use boilers 

 of small dimensions, which are capable of 

 absorbing but a very small part of the 

 heat generated in the combustion of the 

 fuel; consequently the greater part of 

 the heat is carried up the chimney and 

 expended to no purpose. To set this in 

 a clear point of view, it may be necessary 

 to observe, that as an equal quantity of 

 cooled particles will be brought back by 

 the returning-pipe as there were hot 

 particles set in motion by the leading- 

 pipe, it follows that, in a boiler of very 

 small dimensions, these cooled particles 

 would occupy nearly the whole external 

 surface, and would require to be re-heated 

 at every successive circulation; whereas 

 in the cylinder boiler above described 

 they would occupy but a small space at 



the bottom, while, the water above being 

 already heated, the circulation would pro- 

 ceed with greater rapidity. In other 

 words, if the boiler be large, the particles 

 of water would be heated with more rapi- 

 dity than they could possibly circulate 

 through the area of the pipes, and the 

 result would be, that a surplus quantity 

 of heated water would be retained in the 

 boiler, until the whole quantity had 

 attained a high degree of temperature, in 

 which case the quantity of cooled particles 

 brought back by the returning-pipe would 

 have but little effect in lowering the tem- 

 perature of the whole mass ; whilst the hot 

 particles at the upper surface of the 

 boiler would keep up the circulation 

 without interruption, and the contrast of 

 the temperatures between the leading 

 and returning pipes (on which the action 

 depends) would be consequently greater, 

 in the ratio of the difference between the 

 proportions of a small boiler and a large 

 one. 



Fig. 211 is an economical and portable 

 hot-water apparatus invented by Charles 



Fig. 211. 



H. Smith, Esq., of Edinburgh, a landscape- 

 gardener of respectability. It is intended 

 for heating frames and pits, and will be 

 found a useful appendage in the gardens 

 of amateurs — the more so, as it can be 

 readily moved from one pit or frame to 

 another. The fuel employed is coke or 

 gas cinders; and, when properly ignited, 

 the combustion goes on so slowly as to 

 require attendance only once in twelve or 

 fifteen hours. This control over combus- 



