194 MASSACHUSETTS HORTICULTURAL SOCIETr. 



■will indirectly introduce a supply- of fresh air to the house, and in 

 quantity sufficient to keep the air in the house alive and sweet, 

 without the necessit}^ of opening ventilators in dull and unsuitable 

 weather. I do not know of so good a manner to introduce fresh 

 air to a greenhouse as tliis, and at so little expense to the heating 

 apparatus b}- the absorption of heat. 



There should be doors so constructed in one side of the brick- 

 work as to enablf^ one readily to inspect the pipes, and to keep 

 them free from ashes and dust that will lodge upon them. Ashes 

 and dust on boiler-pipes act as a repellent to the heat, thereby 

 causing great waste of fuel, for it takes a great deal hotter fire to 

 heat dirty pipes than clean ones. 



Such a construction as I have tried to describe, it seems to me, 

 will do more heating with less expense of fuel than the very much 

 more expensive apparatus now used in nearly every greenhouse 

 in this section of country can possibly do, and as it is simple in 

 detail, easily comprehended, and not liable to get out of order, I 

 confidently commend it to you as the best heating apparatus for a 

 greenhouse. 



I sincerely hope that ray few remarks will stir up a discussion of 

 the subject which will only end when we accomplish the purpose 

 for which we are assembled, and that is to devise a cheap and 

 economical way of heating greenhouses. 



Since writing out the foregoing remarks I have had my attention 

 called to another gentleman, Mr. George Cartwright, who has been 

 quietly at work with this same end in view (the economical heating 

 of his greenhouse), and, singularh' enough, he has adopted some 

 of my most important suggestions, an^ they work most admirablj'^. 

 He has his stand-pipe close to the boiler ; but in one point it is not 

 constructed as I have proposed, inasmuch as the water from his 

 boiler enters the stand-pipe at the bottom, whereas in ni}' construc- 

 tion it enters about midway, and I think my method best, as it 

 seems to obviate a part of the water pressure from the stand-pipe 

 on the boiler. 



Mr. Cartwright's boiler is cylindrical, and it is also the fire-box, 

 open at the top and bottom, and resting on fire-bricks just above a 

 shake-grate, and the coal is fed in at this top of the cylinder. 

 When he starts the fire a direct draught is opened into the chimney ; 

 but when the fire is well alight the direct draught is closed, and the 

 heat passes, over the top edge of the fire-box and water-jacket, down 

 the outside, all around, and enters the chimney below the boiler. 



