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of the ordinary working size, when preparedwith common cotton wick and the Green-land whale oil, burn during the collier’sshift, or day’s work of six hours, withoutrequiring to be replenished; and the safetytrimmer answers the purpose of cleaning,raising, and lowering the wick completely.”

“ The only inconvenience experiencedarises from the great quantity of dust, pro-duced in some situations by working thecoal, closing up the meshes of the wire-gauze, and obscuring the light; but theworkmen very soon removed this inconve-nience by the application of a small brush.

Our colliers have found it most conve-nient to hang the stationary lamps fromsmall wooden pedestals; but on observing,that where the side of the lamps have beensuffered to come in contact with the pedes-tals, the wood is charred to a considerabledepth by the heat of the lamps; I havethought it right to use small iron, pedestalsinstead of the wooden ones.

Beside the facilities afforded by thisinvention to the working of coal mines,abounding in fire-damp, it has enabledthe directors and superintendants to as-