979 



THE GARDENER. [June 



moniously, and consequently those of nature could not really be re- 

 versed this time : the water was only wrong in taking the wrong course, 

 the pipes being new and coming from Scotland. A iter logically settling 

 this point, the whole on reflection was explained by the fact of there 

 being 10 feet of perpendicular pipe, which contained continuously the 

 coldest and consequently the heaviest portion of the water, and out- 

 balanced the warm water rising in the return. We suffered much men- 

 tal uneasiness in having the laws of nature thus apparently treated so 

 contemptuously by our new apparatus ; so after a few weeks' action, and 

 no change likely to be voluntarily effected in its behaviour, we stopped 

 the fire and cooled the water, and started afresh, this time with full 

 pipes and a proper and orderly course of procedure on the part of the 

 water. The share which the principle of the siphon has in the circu- 

 lation of hot water was thus very excellently and accidentally illus- 

 trated. The boiler, from the nature of the position, was not sunk in the 

 earth, although so much below the upper set of pipes. But after all, 

 the fire is the great mover of the water, as the sun moves the winds : 

 and as an eminent horticultural writer some years ago lucidly ventilated 

 and illustrated the theory of hot- water circulation by showing the effects 

 of the sun in originating the Gulf Stream, whereby the climate of these 

 fortunate islands was maintained at a forcing-house temperature ; and 

 as the water is made to move in a system of pipes independently of the 

 auxiliary principle of the siphon ; — so, after all, the sinking of boilers in 

 deep stoke-holes may not be an expedient of such necessity, if some other 

 auxiliary can be substituted for the siphon. As the cold water, from 

 its density, has a drawing power down an inclined plane, so hot water, 

 from its rarity, may be made to exercise a lifting power, like a balloon, 

 or like smoke up a chimney. 



We have known more than one heating-apparatus erected with the 

 view of taking advantage of this effect of heated water, the motive 

 power on the fire being above the level of the return, in consequence 

 of the difficulty of sinking the boiler. I may say the whole of the pipes 

 connected with the boiler were return-pipes, with just this exception 

 that the heated water rose at once to a considerable height above the 

 boiler, 9 feet at least, where it was discharged into an expansion-box, 

 and thence distributed to the various houses by other pipes opening 

 into the expansion-box — the return-pipes, so to speak, entering level into 

 the bottom of the boiler. The apparatus worked satisfactorily : the 

 gardener was a well-known prize-taker at the district shows. By this 

 plan several difficulties of doors and passages were overcome, which 

 could not have been effected on the siphon principle. One other 

 apparatus we remember, on a large scale on the same principle, fixed 

 by Messrs Weeks. There really seems no reason why of necessity boilers 

 should be fixed below the level of all the pipes : we should, of the two, 

 prefer the siphon principle, of course, as being the most compact and 

 most efficient in application, the law of gravitation being antagonistic 



