Sticking, or Court Plaster.
This plaster is well known from its general use and its healing properties. It is merely a kind of varnished silk, and its manufacture is very easy.
Bruise a sufficient quantity of isinglass, and let it soak in a little warm water for four-and-twenty hours; expose it to heat over the fire till the greater part of the water is dissipated, and supply its place by proof spirits of wine, which will combine with the isinglass. Strain the whole through a piece of open linen, taking care that the consistence of the mixture shall be such that, when cool, it may form a trembling jelly.
Extend the piece of black silk, of which you propose making your plaster, on a wooden frame, and fix it in that position by means of tacks or pack-thread. Then apply the isinglass (after it has been rendered liquid by a gentle heat) to the silk with a brush of fine hair (badgers' is the best). As soon as this first coating is dried, which will not be long, apply a second; and afterwards, if you wish the article to be very superior, a third. When the whole is dry, cover it with two or three coatings of the balsam of Peru.
This is the genuine court plaster. It is pliable, and never breaks, which is far from being the case with many of the spurious articles which are sold under that name. Indeed, this commodity is very frequently adulterated. A kind of plaster, with a very thick and brittle covering, is often sold for it. The manufacturers of this, instead of isinglass, use common glue, which is much cheaper; and cover the whole with spirit varnish, instead of balsam of Peru. This plaster cracks, and has none of the balsamic smell by which the genuine court plaster is distinguished. Another method of detecting the adulteration is to moisten it with your tongue on the side opposite to that which is varnished; and, if the plaster be genuine, it will adhere exceedingly well. The adulterated plaster is too hard for this; it will not stick, unless you moisten it on the varnished side.--The Painter, Gilder, and Varnisher's Companion.
AN IMPROVED HOISTING PULLEY WANTED.
A gentleman of this city has sent us the accompanying diagram of an improved hoisting pulley, for which he say she would be willing to pay any reasonable price provided he knew where to obtain it--the wheel, not the price. It is a pulley within a pulley, the friction of the outer one upon the inner one--the latter being held by a ratchet and pawl-acting as a brake in lowering weights, while both would turn together in elevating weights. The idea is rather an ingenious one, but we are confident our inventors can attain a like object by simpler means.
