this view he has consulted the best authorities, and has not, he trusts, omitted to acknowledge the sources whence his matter has been derived. Where differences in statements or opinions occur, they are placed in juxta-position, so that the reader may have an opportunity of drawing his own inferences, it may be, of exercising his own experimental knowledge on the subject. Indocti discant, et ament meminisse periti. The First Part embraces the physics of the atmosphere, the seasons, temperature, rain, winds, and pressure; the respiration of plants and animals, the circulation of the blood, the chemistry of respiration, and animal heat; infection, contagion, malaria, sewerage, drainage, ventilation, and climate in connection with disease. The SECOND PART will consist of digestion, foods and drinks, their impurities and adulterations. The THIRD and last part will include motion and rest, sleep and wakefulness, secretions, excretions, and retentions, mental emotions, clothing, bathing, &c. Brighton, May 1, 1858. с AIR. CHAPTER I. THE ATMOSPHERE. 1. Earth, form of-The planet which we inhabit is an elliptical spheroid of rotation, of which the lesser axis passes through the poles. The measure of oblateness of the polar diameter isth. The polar semidiameter is about 27 geographical miles shorter than the equatorial semidiameter. 2. Earth, density of.-The mean density of the earth, according to Reich, is 5.44, or nearly 5 times greater than pure water. 3. Earth revolves on its own axis, and travels in its orbit.The earth revolves on its own axis at the incredible rate at the equator of upwards of 1,000 miles an hour; and travels in its orbit at a mean velocity of 68,000 miles in the same space of time. Its diurnal rotation is completed in 86,400 seconds 24 hours. = 4. Earth surrounded by an atmosphere. It is surrounded by an atmosphere (from arμós, "vapour," and opaîpa, “a globe,") or envelope of an admixture of gases, which is indispensable to animal and vegetable life. 1. Kosmos; a General Survey of the Physical Phenomena of the Universe, by Alexander von Humboldt. London, 1845. vol. i. p. 174. 2. Ibid. p. 180. 3. Celestial Scenery; or, the Wonders of the Planetary System displayed, by Thomas Dick, LL.D. pp. 60, 152. B |