Introduction to the study of chemical philosophy : the principles of theoretical and systematic chemistry / by William A. Tilden.

  • Tilden, William A. (William Augustus), Sir, 1842-1926.
Date:
1876
Catalogue details

Licence: Public Domain Mark

Credit: Introduction to the study of chemical philosophy : the principles of theoretical and systematic chemistry / by William A. Tilden. Source: Wellcome Collection.

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    individual cases, we meet with so many exceptions and anomalies, that it is obvious such a law must be applied with extreme caution. It is, however, permissible to say that bodies which are strictly comparable in regard to chemical and other physical qualities do in nearly all cases exhibit the relation referred to. Among the elements the most noteworthy instances are the following:— Molecular Weight. Boiling Point. Chlorine . 71 “5°° Bromine . . 'i6o 63° Iodine • 254 i75° Oxygen . • 32 permanently gaseous Sulphur . . 64 ? 440° Selenion • 159 ? below a red heat Tellurium • 258? white heat Nitrogen 28 permanently gaseous Phosphorus 124 290° Arsenic . . 300 volatilises at red Antimony . 244 ? heat without fusion white heat Bismuth . . 420 ? white heat Groups of similarly constituted compounds show the same relations. Molecular Weight. Boiling Point. Sulphur Dioxide 64 '—I o° Sulphur Trioxide . 80 46° But the most important cases are observable among the carbon compounds, which form homologous series, to which reference will be made hereafter. One example will suffice in this place. The following compounds all contain carbon and hydrogen in proportions which may be represented by the general formula CnH2n + 2:—