GREENHOUSE AND HOTHOUSE FLOWERS 149 



into the wall or woodwork of the house, without a stoke-hole, may 

 be chosen for any structure that does not require more than seventy- 

 five feet run of piping. Above that figure it is desirable to con- 

 struct a stoke-hole, and use a horizontal boiler. There are almost 

 as many different kinds of boiler as there are of motor-car. Any- 

 one who finds a difficulty in choosing from among the various special 

 boilers advertised will be well advised to select a waterway-end saddle 

 boiler. It is a " stock " article with almost every firm of hot-water 

 engineers, and a good one, being powerful and easy to manage. 

 It is quite impossible to say what is absolutely the best of the 

 numerous boilers, suitable for small houses, that are advertised. 

 In the case of all of them success turns principally on skill and 

 care in stoking, and any person with a modicum of common sense 

 can learn to stoke. 



The size of the boiler will naturally depend on the amount of 

 piping, and the latter upon the size and temperature of the house. 

 Gardeners have a simple working rule for calculating the amount 

 of four-inch piping necessary for the different classes of house, and 

 we will quote it for the benefit of inexperienced persons. It is to 

 divide the cubic capacity of the house by 30 for a greenhouse, 

 25 for an intermediate house, and 20 for a stove, taking the 

 result in each case as the number of feet of piping required. 

 The cubic capacity can, of course, be ascertained by multiplying the 

 length of the house by the breadth, and the product by the height. 

 In the case of a span roof, it is hardly fair to take the distance 

 from the floor to the ridge as the actual height ; it is fairer to take 

 the height to the eaves, and then add to it half the height from 

 the eaves to the ridge. 



The setting of an upright boiler is not so serious a matter 

 that it cannot be undertaken by any handy amateur, but it is 

 safer to have a man down from the maker, or if the distance is 

 too great for that, to refer to a local builder. In the horizontal 

 boilers that course is essential. In any case it should be remem- 



