Transcriber's Note
Many omissions of punctuation have been silently corrected, as have obvious typographical errors.
Variations in spelling, punctuation and hyphenation have been retained.
Inconsistencies in headings are as in the original.
Duplicated section headings on consecutive lines have been removed.
The section General Observations (page 94 and 162) has been added to the Table of Contents.
References has been added to the Table of Contents.
Corrections include:
Page 55 "as that two straight lines should enclose a space" the "a" is missing in the original and has been added.
Page 89 "The soul seated in its presence-chamber, the brain, can cognize nothing beyond and without, for nothing can get except where it is present." the first letter of "get" is missing. It has been assumed that get is the most likely intention.
Page 435 No reference to Memdelssohn has been found. It is possibly a reference Moses Mendelssohn.
Page 568 "In order to do this, there is needed an influence from without," The "do" is missing and has been added.
The text is arbitrary about spacing of e. g. and i. e., as the spaced variant is in the majority, it has been used throughtout.
The author has wrongly spelled Leibniz as Leibnitz throughout. This has been retained.
The references to M'Dermot in the text have been changed to McDermot to conform with the References. Likewise M'Cosh (p534) is almost certainly James McCosh.