Punctuation, hyphenation, and spelling were made consistent when a predominant preference was found in this book; otherwise they were not changed.

Simple typographical errors were corrected; occasional unbalanced quotation marks retained.

Ambiguous hyphens at the ends of lines were retained.

Some numbers in equations include a hyphen to separate the fractional and integer parts. These are not minus signs, which, like other arithmetic operators, are surrounded by spaces.

The original book apparently used a smaller font for multiple reasons, but as those reasons were not always clear to the Transcriber, smaller text is indented by 2 spaces in the Plain Text version of this eBook, and is displayed smaller in other versions.

Footnotes, originally at the bottoms of pages, have been collected and repositioned just before the Index.

Devices that cannot display some of the characters used for column alignment in the tables of this eBook may substitute question marks or hollow squares.

Page 59: “95 × 1·623 = 154·185” was misprinted as “95 + 1·623 = 154·185” and has been corrected here.

The Table of Contents does not list the “Phenomena of Heat” chapter, which begins on page 185; nor the Index, which begins on page 242.

Page 95: “adjustible” was printed that way.

Page 151: Missing closing quotation mark added after “rapidly evaporate in space.” It may belong elsewhere.

Page 221: Missing closing quotation mark not added for phrase beginning “it is a fine invention”.