The International Scientific Sfrie*.— (Continued.) 



18. THE NATURE OF LIGHT, with a General Account of Physical Optics. By 



Dr. Eugene Lommel. With 188 Illustrations and a Table of Spectra in 

 Colors. $2.00. 



19. ANIMAL PARASITES AND MESSMATES. By Professor P. J. Van Ben- 



EDEN, University of Louvain. With 83 Illustrations. $1.50. 



21. THE FIVE SENSES OF MAN. By Professor Julius Bernstein. Univer- 

 sity of Halle. With 91 Illustrations. $1.75. 



24. A HISTORY OF THE GROWTH OF THE STEAM-ENGINE. By Pro- 



fessor R. H. Thurston, Cornell University. With 163 Illustrations, $2.50. 



25. EDUCATION AS A SCIENCE. By Alexander Bain, LL. D. $1 .75. 



26. STUDENTS' TEXT-BOOK OF COLOR; or. Modern Chromatics. With 



Applications to Art and Industry. By Professor Ogden N. Rood, Colum- 

 bia College. With 130 Illustrations. $2.00. 



27. THE HUMAN SPECIES. By Professor A. de Quatrefages, Museum of 



Natural History, Paris. $2.00. 



28. THE CRAYFISH: An Introduction to the Study of Zoology. By T. H. 



Huxley, F. R. S. With 82 Illu.strations. $1.75. 



29. THE ATOMIC THEORY. By Professor A. Wurtz. Translated by E. 



Cleminshaw, F. C. S. With Illustrative Chart. $1.50. 



30. ANIMAL LIFE AS AFFECTED BY THE NATURAL CONDITIONS OF 



EXISTENCE. By Professor Karl Semper, University of Wiirzburg. 

 With 106 Illustrations and 2 Maps. $2.00. 



31. SIGHT: An Exposition of the Principles of Monocular and Binocular Vision. 



By Professor Joseph Le Conte, LL. D., LTniversity of California. With 

 132 Illustrations. $] .50. 



32. GENERAL PHYSIOLOGY OF MUSCLES AND NERVES. By Professor 



I. Rosenthal, University of Erlangen. With 75 Illustrations. $1.50. 



33. ILLUSIONS: A Psychological Study. By J.\mes Sully. $1.50. 



34. THE SUN. By Professor C. A. Young, College of New Jersey. With 83 



Illustrations. $2.00. 



35. VOLCANOES: What they Are and What they Teach. By Professor John 



W. JUDD, F. R. S., Royal School of Mines. With 96 Illustrations. $2.00. 



36. SUICIDE: An Essay in Comparative Moral Statistics. By Professor Henrt 



MoRPELLi. M. D.. Royal University, Turin. With 4 Statistical Maps. 

 $1.75. 



37. THE F0RM.\TI0N OF VEGETABLE MOULD. THROUGH THE AC- 



TION OF WORMS. With Observations on their Habits. By Charles 

 Darwin. LL. D., F. R. S. With 15 Illustrations. $1.50. 



