Illustrations have been moved to paragraph breaks near where they are mentioned.

Punctuation has been made consistent.

Variations in spelling and hyphenation were retained as they appear in the original publication, except that obvious typos have been corrected.

Additional notes:

p. 3: Inserted “that” (paper, that give)

p. 6: “choose” changed to “chose” (and chose to)

p. 11: “jar, or a soup-plate” should be “jar, and a soup-plate”

p. 18: “altered as in fig. 4” should be “altered as in fig. 6”

p. 18: “lightness” changed to “tightness” (absolute tightness. Such)

p. 22: “entirely. As” changed to “entirely, as” (out entirely, as)

p. 28: “valve shown in fig. 4” should be “valve shown in fig. 6”

p. 45: “with” inserted (ground, with a)