this instance, and exports yearly, we suppose, about one hundred billion of these fire-tipped splinters.

The ordinary match which we buy at the grocery stores is made by dipping the wooden sticks — impregnated with paraffin or sulphur to sustain combustion in a warm adhesive agent containing an emulsion of yellow phosphorus as the oxidizable constituent, potassium chlorate and manganese dioxide as the oxidizing components, and powdered glass as the frictional element.

Such a match is a remarkably convenient article, as it can easily ignite on the sole of a gentleman's shoe or the back of his trousers. The splint may be broken, but as long as he can find the head at the bottom of his pockets he carries with him the conscious power to set clouds of happy smoke curling from the burning altar of Nicotia.

Unfortunately this match is a menace to safety; it starts innumerable accidental fires, and children die from sucking and chewing it. It will be recalled that Longfellow's first wife, clothed in a light summer dress, happened to step on one of these matches which instantly fed upon her garments and burned her to death.

The Swedish sulphur match is free from this disadvantage, and can be stepped on with impunity, but children should not be encouraged to use it as a substitute for caramels. The head contains potassium chlorate, potassium dichromate, red oxide of lead and antimony sulphide. The oxidizable material on which the match ignites is on the sides of the box, which consists of red phosphorus, antimony sulphide and powdered silica.

In 1771 Scheele investigated the composition of fluospar and noted that the property of etching glass when mixed with sulphuric acid was due to the formation of an acid which he called fluor acid. Scheele's operations had been conducted in glass vessels and what he really obtained was fluo-silicic acid.

In 1774 Scheele showed the difference between pyrolusite