A set of scales will accompany each copy of this work; but any graduated set of scales can be used. All we have to do is to select a scale which contains one-half breast and two and a half inches, in twenty units. Such selection may result in a fractional scale by some, but it can be used. There is no other system in existence by which a forcing scale can be used, and give satisfactory results. (See article on “[Scientific Calculations].”)
Pants.
Scale: One-half seat measure and two and a half inches, divided into twenty parts. Form an angle of seven and a half degrees, and mark it ten numbers wide, at a length of eighty numbers, or one-eighth of its entire length.—The angle of seven and a half degrees has a width of one-eighth of its length. At the top of said angle, or at the width of ten numbers, start the top of pants, and go downward ten numbers for the fork or crotch, and continue downward a distance of thirty-two numbers from the top; again mark eight numbers from the top, or two numbers above the crotch; at the points eight and thirty-two is an even division for the purpose of dividing the angle of seven and a half degrees into three equal parts, or two and a half degrees each; at eight go sidewise three, six and nine, and forward three; at thirty-two go sidewise two, four and six, and forward two; strike lines through two and three, four and six, and six and nine sidewise, and through two and three forward. Each line will represent an angle of two and a half degrees. Except for equal divisions, points eight and thirty-two have nothing of importance about them, neither has the line through four and six, which is also only an even division of the angle of seven and a half degrees in three equal parts; but it will be seen that the angle of seven and a half degrees spreads one-eighth of its length; consequently it contracts one inch in eight, and four inches in thirty-two; hence the width of the angle of seven and a half degrees is six inches at a length of thirty-two whenever it is ten inches at the starting point.
The front line of the angle of seven and one-half degrees I use as a base to work from, but either one of the other lines would be just as suitable a base, particularly the line from two and three sidewise, which is to be the center line of the pants leg, and from which line a right angle each way will be nearer horizontal than any other right angle, when the pants are on the body. Consequently it is a good line to square from for both a level top and a level bottom; but for reasons hereafter explained, it is not a sure line to square from to nick the seams when the foreparts are cut smaller and the backs wider; in fact, no square line is sure for that purpose. But a sweep from the point of the angle of seven and a half degrees will make true connections at any point, no matter how narrow the front or how wide the back may be, or if both be even.
After having formed the angle of seven and a half degrees, and having it divided into three equal parts (or in two and a half degrees each), two and a half degrees, or one part, is placed in front of the angle of seven and a half degrees for the crotch or fork. The seven and a half degrees furnish the outside of the pants leg—that is, one front, one side, and one back, except a small fraction of say three-quarters, which is thrown forward on the top of the front of waist, and is further explained elsewhere.
The top and the front edge of all pants is about one-eighth of the whole waist measure, taken close. But if the question should be asked why it is one-eighth of the close whole waist measure, I must say that I can not give any other reason than that it has proven true in years of practice.