A dictionary of chemistry, on the basis of Mr. Nicholson's: in which the principles of the science are investigated anew, and its applications to the phenomena of nature, medicine, mineralogy, agriculture, and manufactures, detailed (Volume 2).

  • Ure, Andrew, 1778-1857.
Date:
1821
Catalogue details

Licence: Public Domain Mark

Credit: A dictionary of chemistry, on the basis of Mr. Nicholson's: in which the principles of the science are investigated anew, and its applications to the phenomena of nature, medicine, mineralogy, agriculture, and manufactures, detailed (Volume 2). Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

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    but does not ufTVct the epidermis, neither neutralize the same weights of every other does alcohol. Caustic alkali, how ever, dis- acid. For example, 6 parts of potash, or solves it. It resembles coagulated albumen. 4 of soda, neutralize 5 of sulphuric acid; Epsom Salt. Sulphate of magnesia. and 4 4 of potash are adequate to the satu- • EarivALFXTs (Chemical). A term hap- ration of 5 of nitric acid. Therefore, to pilv introduced into chemistry by Dr. Wol- find the quantity of soda equivalent to the laston, to express the svstem of definite ra- saturation of this weight of nitric acid, we tios, in which the corpuscular subjects of need not make experiments, but merely this science reciprocals combine, referred compute it by the proportional rule of Rich- to a common standard, reckoned unity. If, ter. Thus, as 6 : 4.4 :: 4 : 2.93; or in words, as with this profound philosopher, we assume the potash equivalent to the sulphuric acid, oxygen as the standard, from its almost uni- is to the potash equivalent to the nitric acid, venal relations to chemical matter; then so is the soda equivalent to the first, to the calling it unity, we shall have, in the follow. soda equivalent to the second. And again, ing examples, these ratios reduced to their if 6.5 potash saturate 5 of muriatic acid gas, lowest terms, in which the equivalents will how much soda, by Richter's rule, will be be Prime ratios:— The lowest ratio, or equiva- lent prime of oxygen being 1.000 That of hydrogen will be 0.125 Of floor?' - - O.o75 (!f carbon, - - 0.750 Of phosphorus, - 1.500 Of azote, - - 1.750 Of sulphur, - - 2 000 Of calcium, - - 2.550 Of sodium, - - 2.950 Of p< tassium, - - 4.950 Of copper, - - 8.00 Of barium, - - 8.75 Of lead, - - 13.00, &c The substances in the above table, sus- ceptible of reciprocal saturation, can com- bine with oxygen or with each other, not only in proportions corresponding to these numbers, but also frequently in multiple or sub-multiple proportions. We have there- fore two distinct propositions on this nter- esling subject. 1st, The general reciprocity of the satu- rating proportions. 2d, The multiple and submultiple pro- portions of prime equivalents, in which any one body may unite with any other body, to constitute successive binary compounds. The first proposition, or grand law of che- mical combination, wTas discovered by J B Richter of Berlin, about the year 1792. The second, of equal importance, and more re- condite, was discovered so early as the year 1790, by Mr. W. Higgins. Richter inferred his from the remarkable and well established fact, that two neutral salts, in reciprocally decomposing each other, give birth to two new saline compounds, always perfectly neutral. Thus, sulphate of soda being added to muriate of lime, will produce perfectly neutral sulphate of lime and muriate of soda. The conclusions he drew were, 1st, That the quantities of two required for the same effect. We say 6 . 6.5:: 4: 4.3. 3dly, If 10.9 potash combine with 5 of carbonic acid, how much soda will be equivalent to that effect. Now, 6 : 10.9 :: 4: 7.26. Here, therefore, we have found, that if 6 potash be equivalent to 4 soda, in satu- rating 5 of sulphuric acid, this ratio of 6 to 4, or 3 to 2, will pervade all the possible saline combinations; so that whatever be the quantity of potash requisite to saturate 5,10, &c. of any other acid, two-thirds of that quan'ity of soda will suffice. In the same manner let us find out, for five of sulphuric, or of any one standard acid, the saturating quantity of ammonia, magnesia, lime, strontites, barytes, peroxide of copper, and the other bases; then their proportions to potash, thus ascertained, for this acid, will, by arithmetical reduction, give their saturating quantity of every other acid, whose relation to potash, or indeed to any one of these bases, is known. The experimental verification of this most important law, occupied Richter from the year 1791 to the year 1802, in which period lie published, in successive parts, a curious work, entitled the Geometry of the Chemi- cal Elements, or Principles of Stechiometry. We might have expected greater accuracy in his investigations, from the circumstance, that Dr. Wollaston selected his statement of the constituents of nitre, in preference to those of all other chemists, in the construc- tion of his admirable table of chemical pro- portions. With indefatigable zeal Richter examined, by experiment, each acid, in its relation to the bases, and then compared the results with those given by calculation, presenting both in an extensive series of tables. It is curious that he does not seem to have been aware, that all his tables might have been reduced into a single one, of 21 num- bers, divided into two columns, by means of which, every question relating to the inclu- ded articles, might be solved by the rule of three, or a sliding scale. The following ta- 2£KrfSS?S neUtrallze eTal b,e' computed bv Fischer from Richter's latt weight, of any one acid, are proportional to tables, was inserted by the celebrated Ber- the quanbtes of the same bases, requisite to tholle in a note t0 hisychemicd KEJ.