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POPULAR SCIENCE REVIEW. 
from the outer air, and warmed by the large heating surface of 
the back of the grate, increased by flanges, and, after being 
BARRACK COMMISSIONERS’ OPEN GRATE. 
heated from 65° to 70° Fahr., the air passes into the room by a 
shaft cut out of the wall, and which terminates in a louvred 
opening placed ” near the ceiling. This is, we believe, one of 
the best devices yet in operation, and it is the only one we 
should venture to recommend. The plan of heating the air 
of a house by placing a closed stove in the lowest chamber, and 
causing the fresh supply to enter each room at some point above 
the door, is thought satisfactory and efficient by those who have 
tried it, and is said to work thoroughly well in Sir John Robin- 
son’s house at Edinburgh, of which the adjoining woodcut 
represents a section. The air is heated in the basement storey 
by what is known as a “ cockle stove.” Thence it ascends 
along the staircases, and enters the various apartments through 
ventilators above and below the doors. The vitiated air passes 
through apertures in the ceiling of each room, and into a shaft- 
whose outer opening is above the roof of the house. We have 
no personal knowledge of the efficiency of this plan of ventila- 
tion, but it is alleged to be perfect. 
It remains for us to say a word or two about the ventilation 
of sitting-rooms in summer. In warm weather it frequently 
happens that the ventilation of rooms is a matter of some diffi- 
culty. In the daytime, the only natural mode of ventilation is 
