Manner of using the Assay-BALANCE.—Pass a silk string over the three pulleys of the support, and tie it at its upper extremity to the small hook introduced into the hole of the inferior arm; then put the support in the middle of the small case, and pass the other extremity of the silk string below, through a hole bored in the middle of the lower part of the frame, containing the window in the fore-part of the case, and fasten it to a small weight of a cubic form. Suspend the fork of the balance on the inferior hook of the plate. By this means if you move backwards and forwards the weight fastened to the string, placed upon the top of the drawer jutting out beyond the fore-part of the case, the balance within is either lifted up or let down. But you must put the bodies to be weighed, and the weights themselves, into the small silver dishes; and these, when loaded, into the scales, through the side-windows, which must be opened for that purpose. When any thing is to be added or taken out of them, you do it with the small pincers; or, if it is powder, with the small shovel or spoon: but you must let the balance down every time any thing is to be added or taken away, that the scales may rest upon the bottom of the case; and shut the windows before the balance is lifted up again, especially if the air is not perfectly calm.