A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE 



" To the solid ground 

 Of Nature trusts the mind which builds for ^."-^WordswomH 



MACMILLAN & CO., Publisher!, 22 Bond St., NEW YOKE. 



to 1 - 21 ! THURSDAY, MARCH 25, 1880. { annual^bscriftioii »6 



No. 21 



Now Ready. 



LECTURES AND ESSAYS. 



BY THE LATE 



WILLIAM KINGDON CLIFFORD, F.R.S., 



Late Professor of Applied Mathematics and Mechanics in University College, London, 

 and some time Fellow of Trinity College, Cambridge. 



Edited by LESLIE STEPHEN and FREDERICK POLLOCK, with an Introduction by F. 

 POLLOCK. Two volumes, 8vo, $7.50. 

 « In the region of pure mathematics, he was one of the first five or six original thinkers in Europe. As an expounder .0 

 unscientific people of the foundations of science and philosophy, he was almost without a nval. It ,s m thts latter char 

 acter .ha, he is seen in ,he volumes that are now before us-a collection of such of h,s papers and .ec.ures as we« 

 addressed to non-technical audiences."— London Saturday Review. 



SEEING AND THINKING. 



BY THE LAT1 



WILLIAM KINGDON CLIFFORD, F.R.S. 

 Forming the New Volume of the NATURE SERIES ok Scientific Works. i2mo, $1. 

 CONTENTS. -The Eye and the Brain-The Eye and Seeing-The Brain and Thiuking-Ol 

 Boundaries in General. 



UNITS AND PHYSICAL CONSTANTS. 



By I. 1>. EVERETT, M.A., D.C.L., F.R.S., etc.. Professor of Natural Philosophy 

 mi yueen's College, Belfast. i6mo, $1.10. 



MACMILLAN & CO., 22 Bond Street, NEW YORK. 



