We give below several usual compositions of phosphoric mastic for ordinary matches.

Mr. Boetiger has given the two following compositions now in use:-

If glue is used, break it into small pieces; macerate it three boars in cold water, and after-wards melt it in a copper kettle, A, heated over a water bath, B (Fig. 8). When the glue is fluid, and at 212°, take the kettle out, and put it in the circular aperture of a table, G (Fig. 9), which will hold it firmly. Add to it by degrees the phosphorus, which melts immediately, and must always be covered by the aqueous liquid. Begin to stir, in turning the mass, with a wooden scovel covered with hair.

Fig. 8.

Stir all the time till cold, so as to have a well divided emulsion of phosphorus. Then incorporate the sand and the coloring matter.

Kg. 9.

This mixture is kept Quid by patting the dish which contains it over a sand bath, heated to about 97°. Spread that paste, with the help of a- rule, over a marble or cast iron table, which is kept warm by means of a water bath placed under it. Renew that paste by successive additions every time you impregnate the matches.

When gam is used, the operation on the table must be performed while cold, in which case the gam is dissolved beforehand in water, so as to have a convenient provision. This solution thus prepared is used and weighed according to the different formula).

Put the gummy solution into the copper kettle (Fig. 8); heat it to 212° over a water bath; take out the kettle, fix it on the table (Fig. 9); put the phosphorus into it by degrees. It stays in the bottom A'. Beat well in emulsion till cold. This operation lasts about 1 1/2 hour for 7 pounds of phosphorus.

That paste is used like the glue, with the exception that the table is kept cold.

When the matches have been saturated with the paste, the frames are put vertically, so as to dry in the air.

After two or three hours, carry the frames and place them in the oven. When glue is used, the desiccation is completed in one or two hours; with gum it requires 24 hours. This last preparation is the most costly.

The oven must be of incombustible materials, heated gradually and regularly by pipes disposed in the surrounding earth. Steam or water heated by a boiler outside circulates in these pipes.

To avoid having a general conflagration, in case of fire, separate the upright posts which support the frames by vertical plates of sheet iron.

It is desirable to keep on the floor a bed of sand, 4 to 5 inches thick, to avoid setting fire to the matches in walking on them, or when they are on fire, that they may be covered immediately.

When the desiccation is completed, withdraw the frames, and carry them into a room in which they are dismounted. The women who perform that operation must always have near them boxes full of sawdust, into which to dip the matches which may accidentally take fire.

In some of the following chapters we shall treat of the different precautions to be taken to avoid fire, and to prevent the accumulation of vapors in the rooms.