Full capitals may be used with full figures the width of an ordinary letter.
Condensed capitals may be used with en body numerals.
If old-style capitals and figures are required in the same line use figures about one-half larger in body than the capitals and justify them to the line.
It is this difficulty in combining capitals and Arabic numerals in the same line that causes the extensive use of Roman numerals in chapter numbers, numbers of other headings, dates on title pages, and the like.
When a large initial three or four lines high is used for the first letter of a new chapter, large capitals are sometimes used, although such usage is not free from the reproach of looking too much like newspaper advertising.

When this initial is a two line letter it should be in alignment with the small capitals of the upper line and the base line of the text letter of the lower line.
[Illustration: AMONG the earliest methods of communicating ideas to the absent pictures hold the largest place.] [Illustration: THERE comes a tide in the affairs of men which, taken at the flood, leads on to fortune.] Care should be taken not to compact capitals.

Use wider leading and broader spacing than for lower-case; for example, where you would use one lead between lower-case lines you should use two or three between lines of capitals.
Capitals occupy more of the type-body than lower-case letters and consequently words or lines set entirely with capitals need wider spacing and leading than the lower-case to make composition readable.
When lines of roman capitals are set solid or single-leaded the en-quad will usually be enough space between words especially if the words are short; but for wide-leaded lines and head-lines double spaces (two three-to-em) will be needed.

A head-line of round, open capitals may even need em-quad spaces.

Wide letter words require wide spaces and words of thin or condensed letters require thin spaces.
[Illustration: UNITED TYPOTHETAE OF AMERICA UNITED TYPOTHETAE OF AMERICA] Words which begin or end with A Y L V W T may need spaces a little less than those with H I M, etc.