Ventilation. 21 



for this purpose, but place them far enough apart so 

 that the ridge of one will not shade the south bench of 

 the one north of it during the short days of winter. On 

 level ground they should be from 15 to 18 feet apart, 

 according to their height, but if on a slope the distance 

 can be lessened in proportion to its declivity. Each 

 house should be connected at one end with a work 

 room, and if several houses are built it is very conven- 

 ient to have this room in the centre, but its roof should 

 be low in order that it may produce the least amount of 

 shade. While building the walls, if such ventilation 

 cannot be provided as in Fig. 16, put in at least every 12 

 feet, a frame 12 inches wide in the clear, and of a length 

 that will fill the space between two posts. See Fig. 15. 

 This frame should be of sufficient depth to admit of a 

 temporary filling on the inside for winter use, while 

 the door for the outside may be constructed of tlTe same 

 material as the rest of the wall, and hinged so that when 

 shut it shall be fair with its face. These side ventila- 

 tors should be placed in both the north and south walls, 

 and directly against the line of pipes, but under rather 

 than over them. In this way, they can be used at 

 times of the year when the air as it enters the house 

 will be tempered by passing over the pipes. This is 

 of course on the supposition that the pipes are filled 

 with water that has not had time to cool. 



One grower has recently built a house, in the north 

 wall of which he has placed at intervals of 20 feet, reg- 



