Serious objection is properly made to numerous page references under a single heading. For example, in a book on Petroleum, references to every page on which the word petroleum appears would obviously be valueless. The solution lies in concise qualifications of the main titles to reduce to the minimum the actual number of page references opposite each heading.

In the preparation of an index the use of 3×5-inch cards, or paper of sufficient weight to be handled easily and of similar dimensions, is advisable. This enables the author to arrange his subject matter alphabetically and assemble his duplicate references easily. The single and double indentions should be marked on these cards, and the guide words stricken out when indentions are indicated. For single indentions use this mark ◻. For double indentions use ◻◻. If, after the cards are so arranged and marked, it is possible for the author to have the index typewritten in manuscript form, the risk of mixing and loss of cards is minimized and the work of the printer is facilitated.

Some Details of Style.—Because we do not seek uniformity throughout our entire list of books but ask only for uniformity within a manuscript itself, with adherence to any conservative and well-recognized standard, we do not issue a style sheet.

The periodicals with which we are associated (the publications of the McGraw-Hill Company, Inc., Tenth Avenue and 36th Street, New York) have a sheet which is excellent, and which may well serve as a guide to the author who is undertaking the preparation of a manuscript. Or the author may use as his guide any good writer's manual. At the risk of monotonous repetition, however, we urge once more the importance of uniformity throughout the manuscript itself. To this end, we suggest the following:

Spelling.—Follow any one of the standard and well-recognized dictionaries, but follow it consistently. We encounter difficulties especially in the matter of hyphenated words; in using hyphens follow the dictionary.

Abbreviations.—Again, any well-recognized standard will satisfy us. Dictionaries do not, in general, cover the abbreviations of scientific words to a satisfactory extent. We would suggest, therefore, that the author secure the style sheet of one of the leading technical societies in the field in which he works.

For Chemistry . . . . . . . . . . . . .American Chemical Society
For Civil Engineering . . . . . . . .American Society of Civil Engineers
For Electrical Engineering . . . . .American Institute of Electrical Engineers
For Mechanical Engineering . . .American Society of Mechanical Engineers
For Mining and Metallurgy . . . .American Institute of Mining and Metallurgical Engineers
For Economics and Business . .American Economic Association