XXII. The THEORY of SOUND in its RELATION to MUSIC. By Professor Pietro Blaserna. With numerous Illustrations. Sixth Edition.
XXIII. STUDIES in SPECTRUM ANALYSIS. By J. Norman Lockyer, F.R.S. With Six Photographic Illustrations of Spectra, and numerous Engravings on Wood. Fifth Edition. 6s, 6d.
XXIV. A HISTORY of the GROWTH of the STEAM ENGINE. By Professor R. H. Thurston. With numerous Illustrations. Fifth Edition.
XXV. EDUCATION as a SCIENCE. By Alexander Bain, LL.D. Ninth Edition.
XXVI. The HUMAN SPECIES. By Professor A. de Quatrefages, Membre de l'Institut. Fifth Edition.
XXVII. MODERN CHROMATICS. With Application to Art and Industry. By Ogden N. Rood. Third Edition. With 130 original Illustrations.
XXVIII. The CRAYFISH: an Introduction to the Study of Zoology. By T. H. Huxley, F.R.S. Sixth Edition. With 83 Illustrations.
XXIX. The BRAIN as an ORGAN of MIND. By H. Charlton Bastian, M.D. Fourth Edition. With 184 Illustrations.
XXX. The ATOMIC THEORY. By Professor A. Wurtz. Translated by E. Cleminshaw, F.R.S. Seventh Edition.
XXXI. The NATURAL CONDITIONS of EXISTENCE as they affect Animal Life. By Karl Semper. Fifth Edition. With 3 Maps and 106 Woodcuts.