The subjoined scale of the difference in cost was prepared at the instance of the Board.
Mr. Grant took four blocks of houses for examination, and the results are given as a guide to what would be the general expenditure if the change took place:—
“In one block of 44 houses—
The length of drains by back drainage was 1544 feet.
Cost (exclusive of pans, traps, and water in both cases) of back drainage, 83l. 12s., or 1l. 18s. per house.
Cost of separate tubular drainage, 467l. 9s. 6d., or 10l. 12s. 6d. per house.
Cost of separate brick drains, 910l. 19s., or 20l. 14s. 1d. per house.
“In another block of 23 houses—
The length of back drains was 783 feet.