390 Description of a New Roofing Tile. 
Description of a new Roofing Tile manufactured by M. Courtois 
of Paris. Communicated by Sir J. Rosison, K.H., F.R.S.E., 
to the Royal Scottish Society of Arts.* With a Plate. 
Turs form of tile possesses many important advantages over 
those generally used throughout Europe. From the way in 
which the tiles combine at the joints, they may be made, by 
the application of a little mortar or cement, more completely 
wind and water proof than the best slated roof ; as the joints 
afford no lodgment for water by capillarity, none can be blown 
in, and there is none to be affected by sudden frost, the fre- 
quent cause of decay in other tiled roofs. 
An inspection of the plate will sufficiently explain the | pe- 
culiarities of the form, and will serve to shew how the tiles 
are combined in covering a roof. 
It will be obvious that, to make the full advantages of M. 
Courtois’ system available, the tiles must be accurately made 
by good machinery, and that due precautions must be taken in 
drying and firing them, to prevent them from being bent or 
warped, as a small deviation from the normal shape will pre- 
vent that accurate fitting at the joints in which their excel- 
lence consists. The size which is found to be the best for 
these tiles is about 10 inches square, over all; their thickness 
half an inch; the ledges turned downwards on two sides, and 
upwards on the other two, are each half-inch thick, and a half 
inch above the flat surface of the tile, excepting at the upper 
and lower angles, where a small portion of the ledge (as shewn 
in the plate) has double of this projection to enable it to lock 
into the angle, and in the case of the lower angle, to enable 
it to carry the drip to the surface of the next tile below it. 
When manufactured in these proportions, each ‘tile will 
weigh about 42 lb., and sixteen of them will make a square- 
yard of roofing, which will weigh 68 lb. 
The tile donaiiolty used in Scotland weighs 634, and six- 
teen of them likewise make a square-yard, weighing 110 Ib., 
or 42 lb. more than the Courtois tile. 
* Read before the Royal Scottish Society of Arts, 13th December 1841. 
