BOTTOM HEAT. 7 



ductors of heat, destroy its heating power to the extent 

 of the surface they cover. Cast-iron boilers, if properly 

 constructed, are as safe, much cheaper, and last double 

 the time of malleable-iron boilers. 



As a rule, it is much the safest plan to employ a 

 respectable hot-water engineer to erect the heating 

 apparatus,* subject to specifications drawn by some 

 one practically acquainted with the degree of tempera- 

 ture required, and the extent of pipe necessary to that 

 end, the contractor to be bound to keep the whole in 

 working order for one year after erection; and if at 

 this date the boiler is sound, and the joints and valves 

 all right, the inference is that they will continue so 

 for many years. 



The pipes should be painted a dull black colour, as 

 being that most suitable for radiating heat. 



BOTTOM HEAT. 



Gardeners have for many years felt that it was ex- 

 ceedingly unnatural to place the branches of the vine 

 in a high temperature, while the roots were in the cold 

 soil of the border outside the house, and they have had 

 recourse to various expedients to remedy this clearly 

 recognised evil. Hot fermenting dung has been applied 

 to the surface of the border, which did some good, more 

 by its negative than its positive action, in so far as, if 

 the heat from it did not penetrate the border to any 

 depth, it at least, if applied in autumn, prevented the 

 escape of the heat the border had derived from the sun 

 during the summer. Wooden shutters, and in some 

 instances glass, have been laid on the surface of the 



