The chemical pocket-book, or Memoranda chemica : arranged in a compendium of chemistry : with tables of attractions, &c. Calculated as well for the occasional reference of the professional student, as to supply others with a general knowledge of chemistry / by James Parkinson ; with the latest discoveries ; from the London second edition of 1801 ; to which is added an appendix, containing the principal objections to the antiphlogistic system of chemistry / by James Woodhouse, M.D. ... ; embellished with copperplates.

  • Parkinson, James, 1755-1824.
Date:
1802
Catalogue details

Licence: Public Domain Mark

Credit: The chemical pocket-book, or Memoranda chemica : arranged in a compendium of chemistry : with tables of attractions, &c. Calculated as well for the occasional reference of the professional student, as to supply others with a general knowledge of chemistry / by James Parkinson ; with the latest discoveries ; from the London second edition of 1801 ; to which is added an appendix, containing the principal objections to the antiphlogistic system of chemistry / by James Woodhouse, M.D. ... ; embellished with copperplates. 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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    3- Bodies, immediately on being united by it,fuffer a change t>f temperature. This depends on the change which takes place with refpecr to the degree of attraction for the matter of heat. 4. The Compound pofejfes properties differing from thofe 'which nvere before poJJ'effied by the bodies of ivbich it is com- pofed. This difference may exift not only in the tafte, but aLo in the confiftence, form, fmell, colour, fufibility, &c. 5. All bodies have their own peculiar affinities ivith other bodies. Thus fome bodies refufe to unite, whillf. others form an almoft infeparable union. By obtaining a knowledge of the powers of thefe refpec- tive affinities, the rel'ult of different combinations may be previoufiy afcertained. TTiis knowledge is obtained by meafuring the difficulty with which combinations are de- ilroyed, on the application of other fubftances. Thus an acid may be preferved in union with a metal, by a certain degree of elective attraction ; but on an alkali be- ing prefented to this compound, a decompofition takes place, the alkali immediately unites with the acid, forming a new combination, and manifefting a fuperior degree of attraclion, the metal being at the fame time feparated in a precipitate. This is termed a cafe of decompofition by sin- gle elective attraction, ov Jimple affinity, in which one of two principles is difplaced by a third. But when two bodies, each confirming of two principles, ftiffer decompofition, by a reciprocal exchange and union of their elements, by which two new compound bodies are produced, this change is faid to be effected by DOUBLE elective attraction, or double Affinity. Mr. Kir- wan employs the term, £>uiefcent Affinity, to mark that, by virtue of which, the principles of each compound adhere to each other ; and Diuellcnt Affinity, to diftinguifli that by which the principles of one body unite, and change order with thofe of the other. Conlidering the degrees of affinity to be precifely as the points ot fadiration, he therefore marks the degree of af- finity of any body with 311 acid, by the quantity of that bo- dy which may be diflbWed in 100 parts of the acid. Thus fuppoiiug 96 grains of lime to be required to fatuiate 100 grains of nitric acid, he takes 96 for the numerical ex- preffion of its decree or affinity with that acid. The af- finity of pbt-aih with the fame acid he thus finds to be 215, and therefore fays, the affinities of lime and of pot-afli to nitric acid is as 96:215; and that, therefore it may be inferred that a combination of nitric acid and lime mull be decompofed by pot-afh.