_Zeitschr. f. Phys. Chemie._, 1907, 57, 357. Footnote 29: This apparent contradiction in terms the author takes to mean that, whatever compression is produced by pressure on one part of the sphere, is counterbalanced by a corresponding protuberance produced in the part not confined under pressure, the total volume being incompressible. Footnote 30: _Proc. Roy. Soc._, 1898, 63, 270, 286, and 296; 1901, 67, 493. ------------------------------------------------------------------------ TRANSCRIBER’S NOTES 1. Silently corrected obvious typographical errors and variations in spelling. 2. Retained archaic, non-standard, and uncertain spellings as printed. 3. Re-indexed footnotes using numbers and collected together at the end of the last chapter. 4. Enclosed italics font in _underscores_. 5. Denoted superscripts by a caret before a single superscript character or a series of superscripted characters enclosed in curly braces, e.g. M^r. or M^{ister}. 6. Denoted subscripts by an underscore before a series of subscripted characters enclosed in curly braces, e.g. H_{2}O.