Page 152, Footnote [5]: the reference should be to Figs. 63 and 64.
Changes:
Illustrations have been moved outside text paragraphs. Footnotes have been moved to directly underneath the paragraph in which they are referenced.
Some minor obvious typographical and punctuation errors have been corrected silently.
In multiplications and dimensions, x and × have been standardised to ×.
Texts in a dashed box do not occur in the text as such but have been transcribed from the accompanying illustration for improved legibility.
Page vi: The Index has been added to the Table of Contents.
Page 144: ... window and door-jambs ... changed to ... window- and door-jambs ....
Page 271, Fig. 102: Some of the background around the letter A has been erased for better visibility.
Page 274: Rosedale cement changed to Rosendale cement.