Page:The practice of typography; correct composition; a treatise on spelling, abbreviations, the compounding and division of words, the proper use of figures and nummerals by De Vinne, Theodore Low, 1828-1914.djvu/106

 place of roman numerals. The phrase nineteenth century is now more common than XIXth century. The phrases sixteenth Louis, Gregory the fourth, and twenty-second dynasty may displease some readers by their novelty, but it is probable that they will supplant the older form. It is customary in many printing-houses to put a period after the numerical part of the name. The need of the period in this position has never been satisfactorily explained, for XIX is no more of an abbreviation than 19, but it is unsafe for the compositor to suppress it unless so requested. The period is not used with the numerals employed to page a preface, nor for Part II or Canto IV, nor for [chapter] xx, [page] 375, as in a foot-note. A few old printers did, however, rate figures as abbreviations.

Reference figures need not be separated from the text by the marks of parenthesis, as in (1) or 1). The marks so used may be more prominent than old-style figures, and can serve no useful purpose. When the type selected for text and notes is small, a figure of slightly bolder face will be more helpful to the reader.