828

MANUFACTURES.

Manufac- Black Japan.

tures.

'v——' This is made by putting into a set pot forty-eightBlack pounds of Naples or any other of the foreign asphaltums,japar.. (except the Egyptian,) and as soon as it is melted pourin ten gallons of raw linseed oil. Keep a moderate fire,and fuse eight pounds of dark gum animi in the gumpot mixed with two gallons of hot oil and pour it intothe set pot. Afterwards fuse ten pounds of dark or seaamber in a ten-gallon iron pot, keep stirring it whilefusing, and whenever it appears to be over heated andrising too much, lift it from the fire for a few minutes.When it appears completely fused, pour in two gallonsof hot oil, and empty it into the set pot; continue boil-ing it for three hours longer, and during that time in-troduce the proper quantitity of driers, leave it to cool,and afterwards mix it with turpentine.

Water-proof Cloth.

Making (1156.) Various attempts have been made to rendercloth" Pr0 ° f c ' ot ^ water-proof, and these have been attended with moreor less success; but that which has supplanted nearly allothers is a patented invention of Mr. Mackintosh, dated1824, “ for rendering fabrics of hemp, flax, cotton,wool, silk, and various other substances impervious towater.” This is effected by the employment of a thickelastic varnish, made by dissolving caoutchouc in asmall quantity of coal oil. The proportion of coal oilrequired to dissolve a given quantity of caoutchouc willvary according to its peculiar quality, as well as that ofthe resin ; but the average quantity required will beabout a quarter of a pint of the oil to a pound of resin.To facilitate the solution, the caoutchouc is to be cutinto as thin shreds as possible, and the heat of a steambath applied ; when the solution is completed it is to bestrained from the residuum.

To apply the varnish thus prepared, the cloth is to Mechanic* 1be stretched upon frames, and brushed over with it, Proc esses-and the varnished surfaces ol two pieces of cloth, while 'in a sticky yet tolerably hard state, are laid one uponthe other and passed between rollers subjected to pres-sure, which firmly and inseparably unites them. Aflexible and thoroughly water-proof material is thus ob-tained applicable to a variety of useful purposes, withoutthe inconvenient and unpleasant varnished sticky sur-face so common in other water-proof coverings.

This useful invention has found applications in variouscases, but more particularly for large capes, cloaks, andfor great coats, the former principally for walking in,the latter for riding, as they are found w’hen close toowarm for the former. This sort of cloth is also usedfor air cushions and beds, for water-hose and other pur-poses. A very ingenious application of this doth wasalso made in some of our recent Voyages of Discovery,in which it was found necessary to have boats con-structed very light for the convenience of taking themover land. In this instance the boat is made of wicker-work, with a casing of water-proof cloth; and by suchboats very considerable rivers and pieces of water havebeen crossed. Another application was made of thissubstance by Mr. John Cow, of his Majesty’s Dock-yard, Woolwich, who contrived to form bandages of itfor broken limbs. The usual bandages give frequentlygreat pain when any swelling takes place, and they havesometimes to be relieved to the danger of displacing thebone; but by making the bandage of this material, andproviding it with a pipe and stop-cock, the bandage, atfirst but slightly put on, may be blown up to any degreeof pressure required, when, the stop-cock being turned,it will remain so; but on any occasion such as is spokenof above, the cock may be opened and the bandageslackened, and the pressure again restored without inany way disturbing the bandage.

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