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Página 169 - ... even so very hard as never to wear or break in pieces, no ordinary power being able to divide what God himself made one in the first creation.
Página 386 - What is said of its volatility ? upon a sensitive daguerreotype plate suspended a few inches above a vessel containing mercury. Mercury, when pure, is not tarnished by exposure to air and moisture at ordinary temperatures, but when heated to near its boiling point it slowly absorbs oxygen, and becomes converted into a crystalline, dark-red powder, the red oxyd of mercury. This oxyd, when subjected to a dull red heat, evolves oxygen, and is decomposed into its constituents. It was by means of this...
Página 79 - From its extreme softness, its particles slide over each other in the act of expansion, and do not return to their original position. " A leaden pipe, used for conveying steam, permanently lengthens some inches in a short time, and the leaden flooring of a sink, which often receives hot water, becomes. in the course of use, thrown up into ridges and puckers.
Página 191 - Kindled sulphur burns in oxygen with a beautiful blue light. 283. Oxygen and Respiration.— Oxygen is necessary to respiration, and is constantly taken into the lungs, from the atmosphere, in the process of breathing. No animal can live in an atmosphere which does not contain a certain portion of uncombined oxygen.
Página 100 - When a solid is converted into a liquid, or a liquid into a vapor or gas, heat in large quantity disappears, and ceases for the time to affect the thermometer. It is not, however, absolutely lost, but remains incorporated with the substance of the liquid, or the gas, in an insensible condition.
Página 26 - The specific gravity, or specific weight of a body, is its weight as compared with the weight of an equal bulk of some other substance, assumed as the standard of comparison.
Página 492 - ... come in contact with any organ in the body, without yielding to its attraction. The slightest action of a chemical agent upon the blood exercises an injurious influence ; even the momentary contact with the air in the lungs, although effected through the medium of cells and membranes, alters the color and other qualities of the blood.
Página 151 - No elementary substance can be an electrolyte : for from the nature of the process, compounds alone are susceptible of electrolysis. 2. Electrolysis occurs only whilst the body is in the liquid state. The free mobility of the particles which form the body undergoing decomposition is a necessary condition of electrolysis, since the operation is always attended by a transfer of the component particles of the electrolyte in opposite directions. Electrolysis is necessarily a process of electrical conduction,...
Página 97 - In this case, the force of cohesion retains the particles of liquid throughout the mass in contact with each other, in a species of unstable equilibrium; and when this equilibrium is overturned at any one point, the repulsive power of the excess of heat stored up in the mass, suddenly exerts itself, and the explosion is the result of the instantaneous conversion of the liquid into vapor.
Página 225 - Combustion. greater in summer than in winter, and during night than during day. It is also rather more abundant in elevated situations, as on the summits of high mountains, than in plains ; this is probably owing to an absorption of the gas near the surface of the earth by plants and moist surfaces.

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