On the top of the superstructure rests a sheet of perforated boiler-plate. The actual fire-pit is below ground-level, and to the left may be seen parts of the sides and top of the downward approach, from the outside, to the door of the fire-pit.
The openings can be screened by a narrow sloping lean-to, which serves to keep out rain, and provides shelter for the stock of fuel and the coolie. The iron furnace-door should be well made, with an easily worked latch; but it is not necessary that it should be perfectly fitting. Any slight aperture will serve to provide the necessary air-inlet, but in any case it should not be more than slight.
Consumption of Fuel.—Regarding this furnace, it may be said in conclusion that it is more satisfactory in general working than any other furnaces yet encountered. Obtaining information from over sixty estates, on the question of fuel consumption compared with output of rubber, it was found that, as far as ordinary smoke-houses were concerned, the Pataling type of furnace showed the lowest unit consumption of fuel.
General View of Shelters covering Approaches to Furnaces.
This was at the rate of slightly less than 1 lb of fuel per 1 lb of thoroughly cured sheet rubber. The figure on some estates mounted as high as 41⁄2 lbs. of fuel per lb. of rubber. Naturally this factor may have been affected by failure to utilise the drying space to its fullest capacity, but in the main the high rate of consumption could be attributed solely to the deficiencies of the furnaces.
Floor of Furnace-Room.—As a rule no attempt is made to improve the natural earthen floor. Whether open-hearth fires, truck furnaces, or drums are employed, it is usual to find a floor with an inch or two of dust upon it. Where all endeavours are directed in other directions towards cleanliness, it appears strange that this should be overlooked. In contrast, houses employing the Pataling type of furnace (or others) have concrete and cement floors, which can be kept quite clean. Cleanliness should be as zealously attempted in the smoke-house as in other departments.
