32 SMALL WATER SUPPLIES. 



laying the bricks dry has not much to recommend it. 

 Again, the use of ordinary 9 in. x 4^ in. x 3 in. brick is 

 not at all commensurate with the best practice. Stock 

 sizes of radiating bricks (viz., bricks of uniform 

 thickness but tapering in width) are now made by 

 brickmakers for use in sewer and chimney work, and 

 make a much better job, which is out of proportion 

 to their extra cost. The reason why old wells are 



FlG. II. 



found built of rectangular bricks is that certain 

 duties appear to have been levied on bricks other 

 than this shape some years ago. Better perhaps 

 than the wood curb system described, is the use of 

 a cast-iron curb in sections with a cutting edge, as 

 shown by fig. 1 1, as it can be used in loose and wet 

 ground. The brickwork is built on this curb and 

 the men excavate the earth inside it ; meanwhile the 

 curb slips (or should slip) gradually downwards, but 

 the work of letting down the curb demands great 



