562 Abstract Rej)ort of Agricultural Discussions. 
defective construction. The truth is, that concrete requires to be 
used, as it were, in a trench. Now, here* are two facing-blocks con- 
Btrncted on the same principle as those already shown to be applicable 
for brickwork, but of a different form. Suppose the wall to be faced 
on two sides, the bricklayer lays a course of these bricks on the out- 
side and on the inside, to form the thickness ; the labourer follows, 
pouring concrete into the trench thus formed. It woidd be observed 
that the pressure of the concrete on the flange counteracts the outward 
thrust given by the concrete, and thus the concrete is retained just in 
the same way as in the foundation of a building. He had built houses 
costing foui" or five thousand pounds a-piece, where economy was no 
object, upon that plan of construction. Instead of the board being 
removed, the blocks, which are a substitute for the board, remain to 
protect the concrete from the external atmosphere ; and such a v/all is 
as hard and stronger than the very best brick construction ; or again 
the brick face in the interior might be dispensed with, j 
He would now show how it happens that blocks of this particular 
form are cheap enough to be used for cottage building. It is entirely 
owing to the contrivance by which they are burnt in blocks of sis 
together. The blocks are all exactly alike in form, and when passing 
through the die they are held together by clay which had been left 
betv/een the knives or cutters. The block which he now produced I'epro- 
sented six bricks 12 inches long. Hitherto it had been almost an imjjos- 
sibility, even when persons went to the greatest expense, to manufac- 
ture a brick true enough to be used 12 inches in length. With this 
plan of moulding, the joints are found to be straighter and truer than 
they had been in the very best descriptions of work previously. Then 
again, there is the great economy of conveying to the building such a 
very small weight of materials. When it was considered that thcso 
blocks represented twelve bricks on the external face of the wall, it 
would be readily understood that very few such blocks would be ne- 
cessary to construct concrete t\'alls for a cottage. 
Tlie next point to be considered is the flooring. They all knew the 
advantages in warmth and comfort of a wooden floor over a brick or 
<tile floor. Yet a wooden floor has some drawbacks ; for example, if a 
fhouse is left uninhabited for a short time, a quantity of fleas and other 
insects immediately find a habitation there. But a paved floor was 
generally considered, and with good reason, to bo cold and liable to 
..damp. Now, the paving tile which he exhibited J had a flange on one 
■side. Tliis flange extends beyond the face of the tile, so that the 
tile rests on the flange of its neighbour. Longitudinally some ojien- 
ings are formed, by leaving out a small portion of that flange, so tliat 
the air circulates not only longitudinally, from one end to the other 
beneath the paving, but also transversely. There is, in short, a i)cr- 
fcct current of air everywhere bcnciatli the paving. They must often 
have observed that floor-paving got slightly out of the level. It is 
generally supposed that this arises from one tile being softer than 
• See Illustration No. 3. f See Illustration No. 4. 
X See Illustration No. 5. 
