[3] This may be done by making the pass.
[5] All experiments marked thus, *, should be performed on the hob of the grate, to permit the fumes to escape up the chimney.
[6] The eye is to be applied to the little circular hole seen on the upper surface.
[7] The thinnest substance ever observed is the aqueous film of the soap-bubble previous to bursting; yet it is capable of reflecting the faint image of a candle, or the sun. Hence its thickness must correspond with what Sir Isaac Newton calls the beginning of black, which appears in water at the thickness of the seven hundred and fifty thousandth part of an inch.
[8] The pins are only used to hold the pea steady before it is blown from the pipe, as the pea alone will dance quite as well.
[9] D is a good note for it. The upper string may be tuned to the upper D, and the two lower to the lower D, and D D. The "harmonics," are the sounds produced.
[10] Ancestor of the fighting and writing Napiers of our day.
[11] When an exact half cannot be taken without a fraction, he must take the larger half—you must tell him this before he commences. Here it is the larger half.
[12] From Parkes' Philosophy of Arithmetic, a capital work published by Moss & Bro. Philadelphia.