TRANSCRIBER'S NOTE.

1) Figure numbers (which aren't contiguous) have been preserved.

2) Part III, Chapter V. The [table] showing thickness of vitrified pipes reads:

4 inches diameter1/2 inch thick
6 " "1/16 " "
8 " "3/4 " "
12 " "1 " "

The thickness figure for the 6 inch pipe has been left as originally printed, but probably is incorrect (logically it should be somewhere between 1/2 inch and 3/4 inch thick).

3) A larger version of [figure 1] can be viewed by clicking on the figure image.