374 
Report on Drain- Tiles and Drainac/c. 
pipe is received by a boy on a stick, loosely fitting its bore, which 
also gauges the length of each pipe : it is then cut off by a wire, 
placed on a hand-barrow, and carried to the adjoining drying- 
shed by another boy. One man and two boys make about 1800 
per day of the smallest sized pipe. It is requisite that the clay 
be well washed and sieved before pugging, for the manufac- 
ture of these tiles, or the operation of drawing them would be 
greatly impeded by having to remove stones from the small space 
surrounding the die which determines the thickness of the pipe. 
But, it results from this necessary washing, that the substance of 
the pipe is uniformly and extremely dense, whicli consequently 
gives to it immense strength, and ensures a durability which can- 
not belong to a more porous though thicker tile. The clay is 
brought from the pug-mill so dry that, when squeezed through 
the machine, not a drop of water exudes ; moisture is, indeed, 
scarcely apparent on the surface of the raw pipe. Hence, the 
tiles undergo little or no change of figure whilst drying, which 
takes place very rapidly by reason of their form and slight sub- 
stance. They are placed in the kiln when containing only about 
12 per cent, of moisture, in consequence of which there is but 
trifling loss in the burning, which was effected at the Penshurst 
works with brushwood ; but the selling price is the same at other 
works where coals are used at about 20s. per ton. A pipe shrinks 
about 15 per cent, in its length between its raw state from the 
press and when burnt. These particulars refer to the clay at 
Penshurst ; they will vary a little with the nature of the clay used. 
It is estimated that a manufactory of these pipe-tiles may be 
added to any existing brick-field, at an expense of about lOOZ., and 
for a less sum where kilns and pug-mills are in use. This esti- 
mate includes the machine with a single die, a pug-mill, washing 
apparatus, kiln, and drying-shed. The manufacture might be 
carried on throughout the winter by securing the raw pipes against 
frost. This would necessarily occasion some additional outlay, 
but it is thought would not enhance the cost of the tiles, as the 
hands would not lie idle. It is a consequence arising from the 
small dimensions and weight, together with the comparative dry- 
ness of the tile when produced, which properties diminish to a 
minimum the bulk of the material used, and the space required 
for manufacturing and drying. Such an establishment would 
suffice for the annual production of 540,000 tiles, which is equi- 
valent to the annual drainage of about 240 acres of land, from 30 
to 36 inches in depth, at a mean of about 20 feet between the 
drains, and at a cost not exceeding 3/. per acre in clays and firm- 
bottomed soils, unencumbered with stones. 
Other important advantages attend the cylindric figure and 
light weight of the pipe-tiles, viz. the diminished cost of carriage. 
