so it is desirable that the aperture to let the gases out should be
low down in the oven. There are practical objections to placing it
on one side or other of the stove. For, where flues are provided,
the construction of some houses requires a left hand aperture and of
others a right. Thus it is better to put the orifice in the back wa if
of the stove. But, if the burner runs along the back of the stove,
which is a convenient place for it, much of the heat will escape
through any aperture immediately above it without circulating in
the stove. The purpose of the invention is to prevent this conse
quence of having the outlet low down at the back of the oven.
The existence of gas stoves in which the flue outlet is arranged
low down in the oven is presupposed by the specification, which
clearly states that it is to them that the invention relates. A short
passage is adequate to describe the invention. '* For some purposes
it is desirable to arrange the flue outlet at the lower end of the back
of the oven, and it is the object of this invention to enable the flu
outlet to be placed in this position without altering the position of
the burner, and also without adversely affecting the efficiency of
the apparatus. The invention comprises the employment between
rear burner and a rear flue outlet, of a partition which separates th
said parts and enables the gaseous products to pass out of the oven
without interfering with the proper combustion of the gas and th
effective circulation of the hot gases through the oven interior."
A way out is given to the gases by making the length of the
partition, as well as of the burner, less than the entire width of the
oven and so leaving a space at one or both ends. The upper end
of the partition joins the back wall of the oven, and both the flam
from the burner and the ascending heat are thus shut off from the
aperture at the back of the oven. The descending gases pass
through the intervals between the side walls of the stove and the
ends of the partition or, if there be an interval at one end only,
through that. They travel behind the partition to the aperture,
whence they escape into the flue, or in default of a flue, into the
outer air.
The decision of the case depends upon one claim, the first. It
begins with the words, "In gas-heated cooking apparatus of the'
kind specified." This, I think, clearly refers to gas stoves with