1921.] Marsden and Fenton.—Coal, Gas. and Electricity. 259 
II. Tests with a Shacklock Range (Orion). 
The Shacklock range is used practically universally in the Dominion, 
and so its description here is hardly necessary. In the tests the fire was 
lighted with a weighed quantity of coal and kindling-wood, further quantities 
of the former being added at regular intervals. From the total quantity 
of fuel used the total theoretical heat could be deduced. This heat is used 
as follows : (a) Given to the hot-water system, (h) to the oven, (c) to 
kitchen utensils on the top of the range, ( d ) emitted as heat radiation, 
(e) convected by the air in contact with the range, ( f) used in heating the 
air and gases escaping in the flue, (g) used in heating the range and brick 
setting and conducted through the back of the range, (h) unused owing to 
incomplete combustion. 
Hot-water System. .—To measure the heat given to the hot-water system, 
a continuous flow of water was allowed to pass through the boiler and 
cistern, the temperature of the ingoing and outflowing water being measured 
at intervals throughout the whole test. The rate of flow was also measured, 
and the number of heat-units given to the system obtained by integrating 
the product of the rate of flow and the rise in temperature. Two different 
ranges were used, and several tests made with each range, the period of 
firing and test varying from one and three-quarter hours to ten hours in the 
different tests. It was found that the percentage of the calorific value of 
the coal used given to the hot-water system in this way varied little in the 
different tests, the mean being 13 per cent. 
Heat given to the Oven. —The amount of heat given to the oven can be 
controlled by a special flue. In the tests the flue was adjusted so that the 
oven should receive as much heat as possible. For high efficiency it was 
found that a good rate of firing was necessary—about 6 lb. per hour. 
To obtain the amount of heat given to the oven shallow baking-pans 
containing water were placed on each of the shelves, so as to use as much 
of the oven-space as possible. The heat received was estimated from the 
amount of water heated to 100° C. and the amount evaporated during the 
course of the test. It is difficult to devise a test which will satisfy all the 
conditions of cooking in an oven. The above method is fairly applicable 
to stews, but the temperature attained by the oven is considerably less than 
it is in the case of baking or roasting. An equally valuable test would have 
been to find the amount of coal required to be consumed to maintain the 
oven at temperatures such are used in the various cooking operations. 
However, as will be seen later, the above method gave useful information 
by comparison with gas and electricity, for it was found that for ordinary 
use practically the same relative figures are obtained by either test. 
The average result obtained was that 4 7 per cent, of the total heat- 
value of the coal was given to the oven. By specially covering the top of 
the stove with a layer of insulating-material an extra J per cent, efficiency 
could be obtained. Probably a greater increase in efficiency would result 
from the provision of a lagged and polished door to the oven. 
Cooking-utensils 'placed on the Top of the Range .—This test was carried 
out at the same time as tests {a) and (6). Several pans containing water 
were placed on the top of the stove, and the amounts of water heated and 
evaporated during the test were measured. The average result obtained 
was that a maximum of 8*5 per cent, of the heat-value of the coal was 
given to such pans and kettles placed on the top of the stove. 
Radiant Heat given from the Stove. — An exact determination of this 
factor is.somewhat difficult, and only an approximate result was obtained. 
