[18]We see this reddening during an eclipse of the moon (when the event we are describing—an eclipse of the sun visible from the moon—really takes place). The blood-red colour has often struck observers very forcibly, and it has indeed been suggested that the appearance may be the innocent and oft-repeated fulfilment of the prophetic allusion to the moon being “turned into blood.” [19]About 100 years ago London was supplied with water chiefly by pumps worked by tidal mills at London Bridge. [20]The sun and planets are comparatively useless for this object, because of their slow movement among the stars; the change of their positions from hour to hour is so small as to render uncertain the Greenwich times deducible therefrom. Their use would be comparable to taking the time from the hour-hand of a clock. BRADBURY, AGNEW, & CO., PRINTERS, WHITEFRIARS. Albemarle Street, _December, 1873_. WORKS ON SCIENCE, &c. A NATURALIST’S VOYAGE ROUND THE WORLD. By Charles Darwin, F.R.S. With Illustrations. Post 8vo. 9_s._ THE ORIGIN OF SPECIES, BY MEANS OF NATURAL SELECTION; or, the Preservation of Favoured Races in the Struggle for Life. By Charles Darwin, F.R.S. With Illustrations. Post 8vo. 7_s._ 6_d._ THE FERTILIZATION OF ORCHIDS THROUGH INSECT AGENCY. By Charles Darwin, F.R.S. With Woodcuts. Post 8vo. 9_s._ THE VARIATION OF ANIMALS AND PLANTS UNDER DOMESTICATION. By Charles Darwin, F.R.S. With Illustrations. 2 vols. 8vo. 28_s._ THE DESCENT OF MAN, AND ON SELECTION IN RELATION TO SEX. By Charles Darwin, F.R.S. With Illustrations. 2 vols. Crown 8vo. 24_s._ THE EXPRESSION OF THE EMOTIONS IN MAN AND ANIMALS. By Charles Darwin, F.R.S. With Illustrations. Crown 8vo. 12_s._ FACTS AND ARGUMENTS FOR DARWIN. By Fritz Muller. Translated by W. S. Dallas, F.L.S. With Illustrations. Post 8vo. 6_s._ THE STUDENT’S ELEMENTS OF GEOLOGY. By Sir Charles Lyell, F.R.S. With 600 Woodcuts. Post 8vo. 9_s._ PRINCIPLES OF GEOLOGY; or, the Modern Changes of the Earth and its Inhabitants, considered as illustrative of Geology. By Sir Charles Lyell, F.R.S. With Illustrations. 2 vols. 8vo. 16_s._ each. THE ANTIQUITY OF MAN, FROM GEOLOGICAL EVIDENCES; with Remarks on Theories of the Origin of Species by Variation. By Sir Charles Lyell, F.R.S. With Illustrations. 8vo. 14_s._ A GEOGRAPHICAL HANDBOOK OF ALL THE KNOWN FERNS, with Tables to show their distribution. By K. M. Lyell. Post 8vo. 7_s._ 6_d._ A MANUAL OF SCIENTIFIC INQUIRY. For the Use of Travellers. Edited by Sir J. F. Herschel and Rev. Robert Main. Post 8vo. 3_s._ 6_d._ THE CONNECTION OF THE PHYSICAL SCIENCES. By Mary Somerville. Post 8vo. 9_s._ PHYSICAL GEOGRAPHY. By Mary Somerville. Post 8vo. 9_s._ MOLECULAR AND MICROSCOPIC SCIENCE. By Mary Somerville. Illustrations. 2 vols. Post 8vo. 21_s._