Transcriber’s notes:

In this e-book a black underline indicates a hyperlink to a page,illustration or footnote (hyperlinks are also highlighted when themouse pointer hovers over them), and a red dashed underline indicatesthe presence of a concealed comment which can be viewed by hoveringthe mouse pointer over the underlined text.Page numbers are shown in the right margin andfootnotes are at the end. Footnotes arelisted at the end.

The text contains tables, equations and chemicalformulae that might not display correctly on small reading devices – astandard web browser is recommended.

The text of the book has mostly been preserved in its originalform, including inconsistent italics, capitalisation, and hyphenation.However, some defects have been corrected silently, such asmissing/inconsistent punctuation, parentheses and spacing, and anerroneous ÷ has been replaced by − in a fraction in footnote 69. Tableshave been formatted to match the originals, but a large table that wasoriginally split over four pages (pp. 98–101), has been condensed intotwo sections. Some illustrations have been positioned closer to therelevant text and the location may not correspond to that specified inthe list of illustrations.

The following typographic corrections have been made:
mutiplied → multiplied
Kothbeize → Kothbeizen
of → on
phenolphtalein → phenolphthalein
hydroxylion → hydroxyl ion
Ca(OH₂) → Ca(OH)₂
pepsine → pepsin
bibliographic xref (9) → (19)

The following inconsistent spellings have not been altered:
Frankfort a/M – Frankfort o/M
Zenckeri – zenkeri
Casenin – Caseuin
Kentniss – Kenntnis – Kenntniss
resistant – resistent
c.c. – c.cm.
ureaæ – ureæ
ae – æ

The cover image of the book was created by the transcriberand is placed in the public domain.