34 
HEAT AND ITS APPLICATION. 
bedded in mortar, at distances to allow of a flooring to be laid with the best twelve- 
inch paving tiles, jointed with Parker's cement. This floor will form the base of 
the water-course, and upon it three ranks of nine-inch regular paving tiles are 
placed on their edges, jointed and rendered perfectly water-tight with the same 
cement. These tiles are so arranged as to form a double channel, each eight and 
a half inches wide, the two outer ranks resting over the edges of the foundation 
flooring, and the centre rank dividing the channel into two equal courses, one 
communicating with the entering flow-pipe, the other with that of the exit. 
The upper surface is simply covered with slates, two feet long, which extend across 
the whole flue ; and these are also bedded with cement, except at certain intervals, 
equally divided according to the dimensions of the house ; and in each of these one 
slate is made to slide in a zinc frame, correctly grooved. 
The utmost accuracy of manipulation, with materials of first-rate quality, are 
the essential requisites ; and they who can employ their own workmen, superin- 
tending, and even assisting at the work themselves, are most likely to derive 
satisfaction from the machinery. 
The chimney rises from the fire, but at several inches above it, from a cylinder 
of brickwork built upon, and raised a few courses above the upper rim of the boiler ; 
it passes through and along the back-wall at a rising slope to the most convenient 
corner of the house, where it is made to enter a shaft, or wide metal pipe, furnished 
with a damper, on the outside of the house. Six inches in the clear is space 
sufficient for the flue ; but in order to economise every active particle of the heat, 
it ought to run in that direction in which its radiating power will have the 
greatest scope. 
A well-acting, water-tight, pair of channels, such as we have described, filled, 
and kept full, to within one inch, or one inch and a half of the covering slates, 
cannot contain less than from two hundred and fifty to three hundred gallons, and 
this volume of water is made without difficulty very hot, by the interflow of the 
five gallons contained in the boiler. This great effect, however, depends upon the 
rapid combustion, by day, of small quantities of coke not more than sufficient to 
occupy half the depth of the fire-cylinder. Attention and frequent renewals are 
necessary ; and with these, the temperature may be regulated according to that of 
the open air, and the absence or power of the sun. As every cubic foot contains 
1728 cubic inches, and every gallon occupies about 277i mc hes ; as also the water- 
channels just described, being 9 inches deep, and wide, both in the clear ; it 
follows, that every foot, internal measure, is capable of containing 918 cubic 
inches, or three gallons and one-third of water, very nearly. It therefore must 
be evident that a double course of such channels, round any house, must radiate a 
very great volume of heat, provided the furnace be capable of raising the tem- 
perature of the fluid to nearly scalding heat, i.e. about 130° to 140° of Fahrenheit. 
The vapour excited by a new range of flues, while green and damp, is very 
great ; but we have discovered that this abates after a time, when the tiles are of 
