HOT WATER. 315 



Mr. Corbett, foreman at Pontey's nursery garden, Ply- 

 mouth, introduced a mode of employing hot water as a 

 means of heating. From a common boiler proceeds an up- 

 right tube, and this tube leads to a continued series of 

 open gutters. Heat being applied to the boiler, the water 

 rises in the tube and flows forward in the gutters, giving 

 out moisture in proportion to the degree of heat. As the 

 water cools or becomes more dense or heavy, it gradually 

 falls back to the bottom of the boiler. 



Mr. Rendle, of Union Road Nursery, Plymouth, has 

 also introduced a mode of heating, in which he employs 

 tanks instead of pipes, or gutters, for both surface and bot- 

 tom heat. These tanks are formed of wood, brick, stone, or 

 cast iron. When formed of wood, they require to be made 

 of good sound plank, not less than two inches thick, pro- 

 perly jointed, and are usually covered with slates. If they 

 are formed of stone or brick, the insides require a thick 

 coating of Roman cement, and for covers, stone, slate, or 

 brick pavement is employed. The cast iron tanks have 

 corners of the same materials. 



When only one tank is fitted up in a house or pit, a 

 division is made along the centre, leaving an opening at the 

 end farthest from the boiler, for the water to flow through, 

 the hot water or flow pipe from the boiler being fixed to 

 the end of the tank on one side of the division, and the 

 cold water of return pipe to the boiler to the end, on the 

 opposite side of the division. When two tanks are used, 

 they are joined to the flow and return pipes respectively, 

 and united at the extreme ends. In pits, the tanks may 

 be carried round the sides and ends of the pit, with a divi- 

 sion between the flow and return pipes. 



The principal advantage of the application of this mode 

 of heating consists in the production of bottom heat 



