Vol. 21 

 No. 17 



A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE 



'* To the solid ground 

 Of Nature trusts the mind which but Us for aye." — WORDSWORTH 



MACMILLAN & CO., Publishers, 22 Bond St., NEW YORK. 



THURSDAY, FEBRUARY 26. 1880. j a^nu^ubIcSt.on $6 



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 to 

 unscientific people of the foundations of science and philosophy, he was almost without a rival. It is in this latter char, 

 acter that he is seen in the volumes that are now before us — a collection of such of his papers and lectures as were 

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



SEEING AND THINKING. 



BY THE LATF 



WILLIAM KINGDON CLIFFORD, F.R.S. 



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



CONTENTS.— The Eye and the Brain— The Eye and Seeing— The Brain and Thinking— Of 

 Boundaries in General. 



UNITS AND PHYSICAL CONSTANTS. 



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

 in Oueen's College, Belfast. 161110, $1.10. 



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



