FOOTNOTES:
[1] That is, make two bags and sew the edges together, so that actually there will be a third bag between the two.
[2] The figures represent the pairs, i. e., the 1 under M signifies that M belongs to the first pair.
[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.
[13] I. e., at the fourth square from the right angle.
[14] This is done easily enough, but the following directions may not be needless for some. Draw a straight line for a base of any length. If you wish to form a equilateral triangle, i. e. one of which the three sides are equal, divide this base line by two, and at the point of division set up an upright line; then from each end of the base line slant against the central upright line one the length of the base. These, of course, will meet at the top, and the triangle is formed. Any other triangle may be formed in a similar manner, the length of the sides being at the choice of the artist.
[15] Be sure and have the number you name greater than that of the first position of the card in the pack; for instance, twenty-four is greater than thirteen.