Greenhouse Construction 

 Heating: a Greenhouse. 



Over the question of heating a greenhouse much valu- 

 able ink has been spilled. Yet the matter when resolved 

 into its elementary principles is very simple indeed. It is 

 understood that a certain figure on the thermometer must 

 represent the minimum and another the maximum degree 

 of heat, and it is necessary to keep well within these 

 bounds, so that by what means this is accomplished 

 matters little, provided those means are not antagonistic 

 to the growth of the plants, nor extravagantly dear. With 

 gas and oil lamps the great thing is to get reliable appa- 

 ratus, and to understand properly their use and regulation. 

 At this point the great mistake is made. If, however, the 

 fumes from the oil or gas cannot be kept out of the house, 

 then by all means abandon entirely the idea of this form 

 of heating, for in such circumstances it will not act. Per- 

 sonally, however, I strongly advise heating by the hot- 

 water system. 



Here likewise we must jot down a few rudimentary 

 principles, and obviously the first thing to do is to see to 

 the selection of a suitable boiler. There are so many on 

 the market which receive from their makers a host of 

 laudations that it is not surprising that the amateur should 

 feel puzzled, and should be torn by conflicting testimony. 

 Now, if he will take my advice, he will choose what is 

 known as an upright boiler. It is very easy to work, and, 

 if suitably regulated by a damper, a steady heat can be 

 maintained. There are, moreover, no intricate flues, which 

 are often not understood, and the setting is very simple. 

 In fact, I cannot conceive a more suitable form of boiler 

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