374 



THE GARDENER. 



[Aug. 



It will therefore be seen that this boiler is so constructed that all the caloric 

 which the fuel contains is extracted and conveyed to the water, only just suffi- 

 cient to take away the smoke being allowed to escape. Any length of flue can be 

 added, or the boiler can be worked without any flue at all ; and as the glass- 

 houses or buildings are extended, so can lieating power be added. 



It requires no brickwork beyond its foundation to form the ash-pit, and a wall 

 round, as in almost all stoke-holed, to form a frontage ; the latter can, however, be 

 dispensed with. There are no dead plates, solid bars, or bricks in this, as in most 

 other boilers, to burn and crack, thereby admitting a quantity of cold air which 

 tends to cool the water instead of heating it. 



In order that there may be confidence in a boiler, there must be uniform 

 strength in the castings. It is well known that the more complicated the cast- 

 ings, the more difficult is it to procure an equal thickness, while inequality 

 causes unequal expansion and contraction, and occasions fractures and leakages. 

 But in my boiler all the parts are in square sections and equally cast ; conse- 

 quently a regular thickness can be guaranteed. Any of the compartments can 

 be renewed or replaced without destroying the remaining parts, as the boiler is 

 made in sections, and is put together with leakless and durable joints — all that is 

 necessary is a small spanned ; and with this two or three ordinary labourers can 



disELiantle and replace it in a few hours. 

 These joints do away with all fear of frac- 

 ture from expansion or contraction. 



If the damper is carefully worked, it 

 will keep up an intense heat, and the small 

 amount of fuel required will be almost in- 

 credible ; yet it will be found capable of 

 heating a very large quantity of piping in 

 sharp weather with less w^aste of heat and 

 attention than any other boiler. 



Fig. 19 shows it in sections, and how readily 

 it can be connected and disconnected. 



Fig. 20 shows that it can be worked in a 



similar form to the old saddle-back boiler, 



with the advantage of the hollow bars and 



the return-flue above ; and the two ends can 



easily be added at any time by simply removing the plugs which connect them 



with the main part of the boiler. 



Woolwich. H. Cannell, F.R.H.S. 



Fig. 20. 



HEATING, VENTILATING, AND CABBAGE CULTURE. 



As you inform your readers that you wish to have their opinion of your- 

 leader on " Heat and Ventilation," I beg leave to advise you to have 

 it put in stereotype, and let it appear monthly so long as you remain 

 Editor of the ' Gardener '; and if you put it in the hands of every young 

 gardener in the United Kingdom, for, say, twenty years to come, you 

 would probably have dispersed the fungoid diseases that now appear so 

 general amongst the borders of Vines, Peaches, ttc. 



We old gardeners live to see strange events in our business. What 



