with a large annual fair in August, the largest in Italy; has grindstone quarries in the neighbourhood.

When the dampers are very large, say 3 feet or over, they should be set on rollers, like common grindstone rollers; the regulator should be attached directly to the damper, the length of the pipe connecting the regulator with the boiler being of no account.

Some persons add about half an ounce of flowers of brimstone to the above proportions, and a little sludge from the grindstone trough.