'n Account of an Experiment Made to betermine the Potential and Economic Vaporization of a Boiler Progress of the Dephosphorization of Iron. By F. Gantier.. The Involute of the Circumference of a Circle. By L. D'Auria ....... New Pendulum Suspension. By Louis H. Spellier......... Fie Puddling Process, Past and Present. By Percival Roberts, Jr... Advantage of Metallic Lubricants, 21. Magnetic and Diamagnetic Elements, 33. American Laureates 63 HOWSON & SON'S OFFICES FOR PROCURING nited States and Foreign Patents AND PROSECUTING PATENT CAUSES. HENRY HOWSON, Engineer and Solicitor of Patents. CHARLES HOWSON, Attorney-at-Law and Counsel in Patent Cases. Principal Office, 119 South Fourth Street, Philadelphia. Branch Office, 605 Seventh St., Washington, D.C. Authors of "The American Patent System," "Our Country's Debt to Patents," "Answers to Questions of the State Department Relating to Patents." Also, of a "Brief Treatise on Patents," published by Porter & Coates. Jan. '80 1 yr. RUDOLPH M. HUNTER, M.E., C.E., CONSULTING ENGINEER & SOLICITOR -OF United States & Foreign Expert in the Trial of Patent Causes. Examinations in regard to the Validity and Infringement of Patents. Offices, Rejected Cases a Specialty. 901 Walnut St., Dec.. '79 Lyr PHILADELPHIA. |