Punctuation has been made consistent.
Mathematical notation has been standardized to current conventions. For example, the notation 1-2 for fractions has been changed to 1/2.
Variations in spelling and hyphenation were retained as they appear in the original publication, except that obvious typographical errors have been corrected.
[p. 14]: There is no illustration in the original book (This illustration represents)
The following change was made:
[p. 7]: 2 changed to 3 (No. 3, it)