MESSRS. J. J. GRIFFIN AND SONS, LTD., of Kingsway, London, have sent examples of two slide-rules which they are introducing at a very low price—the longer one, which is 25 cm. in length, at 2s., and ...

IN your issue of August 22, Mr. A. B. Basset asks for solutions of the two problems, the trisection of an angle by means of the cissoid, and the duplication of the cube by the conchoid. I happened to ...