THE ALUMNI JOURNAL 51 



emulsion of yellow Phosphorus as the oxidizable constituent, Po- 

 tassium Chlorate and Manganese Dioxide as the oxidizing com- 

 ponents, and powdered glass as the frictional element. 



Such a match is a remarkably convenient article, as it can easily 

 io-nite 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 

 1>ottom 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 innu- 

 merable, 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 en- 

 couraged to use it as a substitute for caramels. The head contains 

 Potassium Chlorate, Potassium Bichromate, red Oxide of Lead and 

 Antimony Sulphide. The oxidizable material on which the match 

 ienites is on the sides of the box. which consist of Red Phosphorus, 

 Antimony Sulphide and powdered Silica. 



In T77I 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 (Man- 

 ganese Dioxide) and Magnetite, which previous chemists had con- 

 sidered identical. 



He explained how Manganese colorizes and decolorizes glass, 

 and distinguished the salts of the lustrous metal, including the green 

 and purple compounds with potash. In fact, he may be considered 

 the discoverer of this element. 



In this year he also discovered Baryta (Barium Oxide), a heavy, 

 w^hitish-gray, poisonous compound, used for plate-glass manufac- 

 ture, in color-making, and in the preparation of Oxygen by the Brin 

 process : 



BaO + O = BaO, = BaO -f O 



This should have been enough for one year, and Scheele 

 ought to have remembered that Nature herself sleeps half the time, 

 but instead of that he discovered Chlorine in the following way : 



MnO^ + 4HCI = MnCL + 2H,0 -f CL 



