The Second Step in Chemistry: Or, The Student's Guide to the Higher Branches of the Science

J. Churchill, 1864 - 774 páginas

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Página 483 - When the formulae of inorganic chemical compounds are considered, even a superficial observer is struck with the general symmetry of their construction ; the compounds of nitrogen, phosphorus, antimony, and arsenic especially exhibit the tendency of these elements to form compounds containing...
Página 679 - The colloidal is, in fact, a dynamical state of matter, the crystalloidal being the statical condition. The colloid possesses Energia. It may be looked upon as the probable primary source of the force appearing in the phenomena of vitality. To the gradual manner in which colloidal changes take place (for they always demand time as an element) may the characteristic protraction of chemico-organic changes also be referred.
Página 192 - A very valuable use of electro-chemical equivalents will be to decide, in cases of doubt, what is the true chemical equivalent, or definite proportional, or atomic number of a body ; for I have such conviction that the power which governs electro-decomposition and ordinary chemical attractions is the same...
Página 192 - I have such conviction that the power which governs electro-decomposition and ordinary chemical attractions is the same ; and such confidence in the overruling influence of those natural laws which render the former definite, as to feel no hesitation in believing that the latter must submit to them also.
Página 218 - The method here employed, of stating the rational constitution of bodies by comparison with water, seems to me to be susceptible of great extension, and I have no hesitation in saying that its introduction will be of service in simplifying our ideas, by establishing a uniform standard of comparison by which bodies may be judged of.
Página 137 - Mercuric iodide separates from solution, and likewise sublimes at a very gentle heat, in scarlet tables belonging to the dimetric system; but when sublimed at a higher temperature in sulphur-yellow, rhombic tables of the monoclinic system. The red crystals turn yellow when heated, and resume their red tint on cooling. The yellow crystals obtained by sublimation retain their colour when cooled ; but, on the slightest rubbing or stirring with a pointed instrument, the part which is touched turns scarlet,...
Página 679 - It may remain fluid for days or weeks in a sealed tube, but is sure to gelatinize and become insoluble at last. Nor does the change of this colloid appear to stop at that point ; for the mineral forms of silicic acid, deposited from water, such as flint, are...
Página 676 - A certain parallelism is maintained between the two classes, notwithstanding their differences. The phenomena of the solution of a salt or crystalloid probably all appear in the solution of a colloid, but greatly reduced in degree. The process becomes slow; time, indeed, appearing essential to all colloidal changes. The change of temperature, usually occurring in the act of solution, becomes barely perceptible.
Página 675 - Every physical and chemical property is characteristically modified in each class. They appear like different worlds of matter, and give occasion to a corresponding division of chemical science. The distinction between these kinds of matter is that subsisting between the material of a mineral and the material of an organized mass.
Página 679 - Even while fluid a colloid may alter sensibly, from colorless becoming opalescent; and while pectous the degree of hydration may become reduced from internal change. The gradual progress of alteration in the colloid effected by the agency of time, is an investigation yet to be entered upon.

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