24 FEBRUARY 1923, Page 15

discovered by two Danish chemists, Coster and Hcvesy. Will you

allow me to correct that statement ? Mr. Coster is a Dutchman. He is a Doctor of Science (Mathematics and Physics) of Leyden University and a Doctor of Engineering of Delft University.—I am, Sir, &c., P. GEYL. 15 Finchky Road, N.W. 8, February 15th.