This section is from the book "The Manufacture Of Boots And Shoes: Being A Modern Treatise Of All The Processes Of Making And Manufacturing Footgear", by F. Y. Golding. Also available from Amazon: The Manufacture Of Boots And Shoes.
The average well-formed foot could be classed, and a table prepared giving the measurements of the various classes. If standard feet measurements were adopted, and the allowances for sub-stances of materials, etc., agreed upon, it would be possible to avoid the misunderstandings so common with standard last measurements. For instance, a standard foot-measure for a lady's foot measuring in state of repose would be (say), length, 11/2 sizes; bottom-width, 3 in.; joint, 8 in.; instep, 81/2 in. Add the length-allowance of 21/2 sizes, this would give size 4's. Deduct for light material, 1/4 in. on instep and in. on joints, giving joint 77/8 in. and instep 81/4 in. If for heavy material, the deduction would not be made, and for other classes fixed allowances would be made. Supposing this were called (say) " C "foot, it could be so stamped on the lasts and boots, with a letter or figure denoting the allowance.
This, if properly carried out, would enable the person who possessed this foot to always obtain a boot or shoe that would be of suitable measurement to suit the kind of foot, without causing a large variety of measures to be in existence without denomination, such as is found under the now marked "3 fitting." The difference in widths and girths are usually termed "fittings," and are numbered 0 to 6. They are also named as follows :0, Narrow fitting.
1, Slim fitting.
2, Smart fitting.
3, Medium fitting.
4, Full fitting.
5, Wide or extra full fitting.
6, Extra wide or XX full fitting.
The joint-girth usually decides the fitting, but a fitting should not merely be an increase or decrease in circumference. The reason of the differences required in fittings is due to the various stages of development of feet, and the shape-characteristics must be provided for, besides the girths. For instance, a narrow or slim foot has the joints undeveloped, and gives the appearance of an arched instep, while a broad foot would appear to have a low instep. The difference between the instep and joint measurements is greater in the slim foot than is found in the wide foot. The larger the fitting the less the difference between the joint and instep measures, and the smaller the fitting the greater the difference. This difference is termed "rise." In a well-developed or wide foot, the joint is found to have developed in a greater degree than the instep, hence there is less rise. Feet do not vary so much in the posterior as in the anterior portion.
The Principles upon which a Scale of Measurements should be based are: first, that as the length-measures are of equal length throughout the scale (1/3 in.), so should the various girth-measurements be equal throughout their respective ranges.
For instance, the amount adopted for joint-girth increase should be the same between any two consecutive sizes as between any other two joint-girth measurements in the same range.
The same amount, however, must not be used both for joint-girth and instep-girth, as the joint are greater than the instep increases.
Secondly, that a greater difference should exist in the rise of adult measurements than in infants'.
In some cases this rule has been applied coupled with another that, however, is not quite accurate; viz. that in a last of half the length of an adult there should be one-half the rise. "Aiders" scale is based upon this rule.
Thirdly, that in the measurements of girth between size and size, the difference between the joint and instep girths - i.e. "rise " - increases from the smaller to the larger sizes, but in the "fitting" measurements the rise decreases from the smaller to the larger fitting.
For instance, in sizes, the rise between an adult measure would be, say, 1/2 in.; whereas in the infants' it would only be, say, 1/4 in., with a graduation between, In fittings, the rise in adults' would be, say, 1/2 in.; in a larger fitting it would be less, say 2/8 in., and in smaller fittings it would be greater, say -6/8 in.
Fourthly, the difference between "fitting" measurements in infants' should be less than in adults'.
If the difference between joint and joint of "fittings"' in adults' be, say, 5/18 in., the infants' would be, say, 5/36 in.
A scale of measurements that contain these requirements will be suitable to the development of feet, and if the proper shape be given to the infants' and adults' respectively, with the alterations required for fittings, a reliable table will be obtained suitable for average-proportioned feet.
An Examination of the Tables of Measurements of Lasts now in Use, will show that there are few that comply with the requisite conditions. The scales used in England are many, and each person adopts his own standard, so that uniformity is not found even in the scales of a district or a manufacturer. Nearly all the scales in use are not conformable to the first essential principle. The various tables may be grouped as "1/4-in. system," "irregular graduation," "1/9-in. method," "Alden's method," etc.