190 MASSACHUSETTS HORTICULTURAL SOCIETY. 



the boiler, and is on its wa}' up the chimne}'? If we cannot use 

 this waste heat in anj- other way I think my suggestion of a coil 

 of pipe in the chimney a good one where forced water is used, for 

 all the water passing through it would become warmed to such a 

 degree as to make it much more acceptable to growing plants than 

 cold water, direct from the service-pipe or cistern. 



The other gentleman to whom I alluded has constructed with 

 his own hands a bank of pipe with the ends built into the sur- 

 rounding brickwork and a fire-box underneath. The construction 

 is fault}-, and not to be recommended. On the top of the brick- 

 work he has enclosed another space, through which he carries the 

 water pipe to irrigate his growing crops. No doubt this last pro- 

 cess will be beneficial, yet b}' it he does not utilize the waste heat, 

 but is drawing constantly from the heated furnace. Therefore I 

 am of the opinion that he would get still better results by carr}'- 

 ing the irrigating water through a coil of pipes in the chimne}-. 

 We all know that the temperature of a greenhouse can readil}'^ be 

 reduced, and the groM'th of plants sadly checked, by the promis- 

 cuous introduction of cold water ; and, therefore, we see the neces- 

 sit}' of providing an economical means of supplying only warm 

 water to growing plants. 



Taking the foregoing remarks as a basis for my superstructure, 

 I would further say, that a greenhouse heater should be constructed 

 on scientific principles, such as shall secure adaptability for the 

 purpose for which it is intended, together with simplicity of con- 

 struction, and ease of getting at it for cleaning and repairs. 



Under tlie first proposition we will sa}' that the method of 

 heating greenhouses by pipes conveying either hot water or steam 

 is now conceded to be the best in use, and this presents the vital 

 question : How can we heat water most economically and most 

 expeditiousl}'? Shall we continue, blindl}-, to use those boilers 

 which are constructed in such a manner as to present to the fire a 

 great mass of water in one solid bod}' to be heated, or shall our 

 boiler be constructed of pipes whereby the same body of water 

 shall be exposed to the warming influence in small streams, and 

 with augmented heating surface in the same space? 



It strikes me that the same fire will heat the same quantity of 

 water if divided in small tubes much more quickly, and to a 

 more intense heat, than if in one body. Now it is an established 

 fact that the hotter water can be made in the boiler, the faster it 

 will circulate through the pipes, and in this way, and this only, 



