204 Fuel Economy. (April, 
air of the room, is obviated. When this grate is used in 
dwelling-houses two rooms can be heated by the same fire— 
the open fire serving for one room, and the heated fresh air 
being thrown into the next. . 
Thomas Whitwell exhibits a grate on a similar principle. 
By his fire-place he injects warm air into the room at a tem- 
perature between 65° and 115° F. 
Rogerson and Co. show Corbitt’s Improved Economic 
Warming and Ventilating Grate. It is simple in construc- 
tion. The best points of the modern grate are preserved, 
viz.—The cheerful open fire; large reflecting and radiating 
surface ; reduced size of fire-box, with convex back, which 
is composed of fire-brick, and, being a bad conductor, throws 
the heat into the room; the draught-flue, opening into the 
chimney, is regulated by Louvre valves, so that no waste 
heat need pass up the chimney beyond the products of com- 
bustion. 
The most successful and ingenious fire-grate in the 
Exhibition is the invention of the Rev. J. Wolstencroft, 
and is called the Vacuum Draught. ‘The inventor says the 
great difficulty is solved, viz., ‘“how to get a healthy, 
cheerful fire, imparting a genial heat, with half the amount 
of fuel commonly used.” We saw the grate in use, and 
we must candidly admit it was the most cheerful and the 
brightest fire in the place, but as to the amount of coal it 
daily consumed we are unable to say. According to some 
experiments which have been performed with it by James 
D. Curtis, Commander Royal Navy, there is truth in the 
inventor’s statement, that there is a great economy in the 
consumption of fuel. Captain Curtis, of Brimpsfield, 
Gloucester, experimented with the grate in his harness- 
room from the 18th of August, 1873, to the 1st of Sep- 
tember, 1873, using no other fire, burning slack coal 
delivered for 24s. per ton, employing this fire daily for 
cooking small things, such as boiling potatoes for the fowls, 
&c., and after the daily use the fire was left to burn itself 
out during the night; the cost of coal per day was 33d. 
The front of the grate is continued down to the floor, 
cutting off the supply of air from within the room ; by this 
means an air chamber is formed under the grate, to which 
the air is communicated from within or without the building, 
bringing the draught under and directly through the fire- 
bars. Ina fire-grate which has been fitted up in Manchester, 
at the office of one of the Local Boards, the air-chamber 
communicates with the main sewer, and draws its supply 
from thence, thus, as it is supposed, ventilating the sewer, 
