THE TANK MODE OF HEATING. 



197 



consist in its having as much surface of 

 boiler presented to the fire as possible, 

 and the most effectual prevention of loss 

 of heat through flues, &c. ; and having an 

 equal distribution of heat throughout the 

 house, by means of a quick circulation of 

 water, whether through pipes, gutters, or 

 tanks. These advantages once secured, 

 the question as to quantity of water is to 

 be regarded as one of convenience, rather 

 than one of expense." 



There is as much heat given out from 

 2 or 3 inches in depth of water as from 

 2 or 3 feet, provided the fire be kept 

 constantly burning. The shallower the 

 water, the sooner will the house be heated ; 

 and the deeper it is, the longer will the 

 heat continue to be given out. Mr Ren- 

 dle appears to advocate a depth of from 

 8 to 12 inches, and reasonably enough 

 observes, that if this body of water be 

 once heated, it will maintain the tempera- 

 ture of the house or pit long after the fire 

 may be extinguished ; or when once this, 

 or even a greater body of water is heated, 

 the fires may be allowed to go out al- 

 together for a time. Thus, for example, 

 to do away with attendance during the 

 night, the water could be heated during 

 the day. It does not appear to us quite 

 clear how firing during a part of this 

 time only tends to the economy of fuel — 

 a subject one should never lose sight of. 



To generate a large body of heat in a 

 chamber or compartment from which 

 it could escape only at the will of the 

 operator, is a desideratum in horticul- 

 ture. This we have long thought of ; 

 indeed the idea arose from a perusal of 

 Dr Anderson's work, many years ago, in 

 which he proposes to collect and store 

 up solar heat during warm days, in 

 a chamber attached to the house to be 

 heated. Over air we seem to have little 

 control, either as a conductor of heat or 

 as a medium to hold it in suspension. 

 Water is quite a different thing, for it is 

 heated readily ; and when once charged 

 with caloric, it retains it for a time, and 

 gives it out gradually. This object, we 

 think, can be effected by rendering, as we 

 intend to do at Dalkeith, the whole pit of 

 a pine stove, originally intended for tan or 

 leaves, a waterproof cistern, filling it with 

 water, and heating the whole mass by con- 

 necting it by flo w and return pipes with the 

 boiler. The fire may then be greatly re- 



duced, or indeed for many hours, nay, days, 

 entirely extinguished — more especially 

 during summer, when bottom heat is re- 

 quired artificially at a time we have suffi- 

 cient atmospheric heat naturally. It is, 

 under all circumstances, important to have 

 the tanks covered, so as to exclude earthy 

 or other matter from getting into them, 

 which would find its way into the boilers, 

 and soon destroy their bottoms. This 

 covering should, however, only be of 

 slates or thin pavement, both of which 

 are cheap and durable, and readily allow 

 the heat to pass through them. The 

 joints should also be made quite tight 

 with cement. Iron covers, as well as iron 

 tanks, are objectionable, on account of 

 their tendency to corrode, and for other 

 reasons elsewhere stated. There is no 

 doubt but that iron radiates heat better 

 than wood, earthenware, or stone ; but 

 whether what is gained in this respect is 

 not more than lost in others, is question- 

 able. 



Wooden tanks may be used with every 

 propriety where the heat is required to 

 rise perpendicular from them; and if 

 made of good Baltic timber, they will last 

 for years, as may be seen exemplified in 

 any brewhouse, where coolers have lasted 

 for half a century. They ought to be of 

 inch-and-half deal, grooved and tongued, 

 and the joints put together with white 

 lead. It would be an advantage, also, to 

 tie the sides together, by running a small 

 iron rod every 6 or 8 feet, headed at the 

 one end, and having a nut and screw at 

 the other, to be placed within 2 inches of 

 the top of the tank. It is a great mistake 

 to cover either wooden or other tanks with 

 wood, as its well known non-conducting 

 powers prevent the heat from rising. For 

 this reason, close wooden troughs are the 

 most proper vessels for conveying hot 

 water through places not requiring to be 

 heated, such as connecting the tanks in 

 one range of pits, &c, with those in an- 

 other running parallel, or in conveying 

 the water from the neighbourhood of the 

 boiler to a house or pit at some distance 

 from it. Metallic pipes may be also used 

 for this purpose ; but they should be in- 

 variably enclosed in a wooden case, or 

 packed round with sawdust, charcoal, or 

 other non-conducting medium, to prevent 

 the escape of heat. 



Brick tanks, properly cemented, are 



