stick of it in a bottle under kerosene and once a year he whittled off a piece the size of a pea and threw it into water to show the class how it sizzled and gave off hydrogen.  The way to get cheaper aluminum was, it seemed, to get cheaper sodium and Hamilton Young Castner set himself at this problem.  He was a Brooklyn boy, a student of Chandler’s at Columbia.  You can see the bronze tablet in his honor at the entrance of Havemeyer Hall.  In 1886 he produced metallic sodium by mixing caustic soda with iron and charcoal in an iron pot and heating in a gas furnace.  Before this experiment sodium sold at $2 a pound; after it sodium sold at twenty cents a pound.

But although Castner had succeeded in his experiment he was defeated in his object.  For while he was perfecting the sodium process for making aluminum the electrolytic process for getting aluminum directly was discovered in Oberlin.  So the $250,000 plant of the “Aluminium Company Ltd.” that Castner had got erected at Birmingham, England, did not make aluminum at all, but produced sodium for other purposes instead.  Castner then turned his attention to the electrolytic method of producing sodium by the use of the power of Niagara Falls, electric power.  Here in 1894 he succeeded in separating common salt into its component elements, chlorine and sodium, by passing the electric current through brine and collecting the sodium in the mercury floor of the cell.  The sodium by the action of water goes into caustic soda.  Nowadays sodium and chlorine and their components are made in enormous quantities by the decomposition of salt.  The United States Government in 1918 procured nearly 4,000,000 pounds of chlorine for gas warfare.

The discovery of the electrical process of making aluminum that displaced the sodium method was due to Charles M. Hall.  He was the son of a Congregational minister and as a boy took a fancy to chemistry through happening upon an old text-book of that science in his father’s library.  He never knew who the author was, for the cover and title page had been torn off.  The obstacle in the way of the electrolytic production of aluminum was, as I have said, because its compounds were so hard to melt that the current could not pass through.  In 1886, when Hall was twenty-two, he solved the problem in the laboratory of Oberlin College with no other apparatus than a small crucible, a gasoline burner to heat it with and a galvanic battery to supply the electricity.  He found that a Greenland mineral, known as cryolite (a double fluoride of sodium and aluminum), was readily fused and would dissolve alumina (aluminum oxide).  When an electric current was passed through the melted mass the metal aluminum would collect at one of the poles.

In working out the process and defending his claims Hall used up all his own money, his brother’s and his uncle’s, but he won out in the end and Judge Taft held that his patent had priority over the French claim of Herault.  On his death, a few years ago, Hall left his large fortune to his Alma Mater, Oberlin.