Transcriber's Note:
Illustrations have been moved closer to their relevant paragraphs.
The page numbers in the List of Illustrations do not reflect the new
placement of the illustrations, but are as in the original.
The list of "didactic material for the _education of the senses_" on
pages 18-19 is missing item (j) as in the original.
Author's archaic and variable spelling is preserved.
Author's punctuation style is preserved.
Passages in italics indicated by _underscores_.
Passages in bold indicated by =equal signs=.
Typographical problems have been changed and are listed below.
Transcriber's Changes:
Page vii: Was 'marvellous' [In fact, Helen Keller is a =marvelous=
example of the phenomenon common to all human beings]
Page 46: Was 'anvles' [which vary either according to their sides or
according to their =angles= (the equilateral, isosceles,
scalene, right angled, obtuse angled, and acute)]
Page 63: Added commas [recognized and arranged in order--doh, _re_,
=doh,= re, _mi_; doh, =re,= mi, _fah_; doh, =re,= mi, fah,
_soh_, etc. In this way he succeeds in arranging all the]
Fig. 35 caption: Was 'si' [the spaces which remain where the discs
are far apart: do-re, re-mi, fah-soh, soh-la, la-=ti=. The
discs for the semitones]