XVIII. The Nature of Light. With a General Account of Physical Optics. By Dr. Eugene Lommel. With 188 Illustrations and a Table of Spectra in Chromo-lithography. Third Edition. Crown 8vo, 5s.
XIX. Animal Parasites and Messmates. By Monsieur Van Beneden. With 83 Illustrations. Third Edition. Crown 8vo, 5s.
XX. Fermentation. By Professor Schützenberger. With 28 Illustrations. Third Edition. Crown 8vo, 5s.
XXI. The Five Senses of Man. By Professor Bernstein. With 91 Illustrations. Fourth Edition. Crown 8vo, 5s.
XXII. The Theory of Sound in its Relation to Music. By Professor Pietro Blaserna. With numerous Illustrations. Third Edition. Crown 8vo, 5s.
XXIII. Studies in Spectrum Analysis. By J. Norman Lockyer, F.R.S. With six photographic Illustrations of Spectra, and numerous engravings on Wood. Third Edition. Crown 8vo, 6s. 6d.
XXIV. A History of the Growth of the Steam Engine. By Professor R. H. Thurston. With numerous Illustrations. Third Edition. Crown 8vo, 6s. 6d.
XXV. Education as a Science. By Alexander Bain, LL.D. Fourth Edition. Crown 8vo, 5s.
XXVI. The Human Species. By Professor A. de Quatrefages. Third Edition. Crown 8vo, 5s.
XXVII. Modern Chromatics. With Applications to Art and Industry. By Ogden N. Rood. With 130 original Illustrations. Second Edition. Crown 8vo, 5s.