Page:Popular Science Monthly Volume 78.djvu/233

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Oral and Printed Presentation.—At the close of a study, an investigator naturally wishes to make report of his results and thus to submit them to the criticism of others than himself and his immediate teachers. He has then to consider whether the report shall take the form of an oral statement before a conference of his associates, or a written essay to be printed in a scientific journal for near and distant readers. There are certain striking differences between the styles appropriate to these two forms of presentation. An oral report ought to be so clear that its meaning can be apprehended during its presentation; hence it must be neither so terse as to be obscure, nor so full of detail as to be confusing. It should be spoken, rather than read from manuscript, because the style of a written presentation is usually so condensed that it is not easily understood when read aloud. A printed report may, on the other hand, either from terseness of style or from abundance of detail, require more than one reading before its full value is learned. A printed report may, if desired, be condensed into a short paragraph of ten or twenty lines, giving only an abstract of results; or it may be expanded to fill many pages. An oral report should not be 80 short as to seem abrupt, or so long as to be fatiguing. An oral report can not be followed easily, if it contain many local names, or numerous quantitative statements and bibliographic citations; but such details are appropriate enough in a printed report, if the subject treated and the space allowed makes them desirable. The selection of topics and the order of presentation should be very carefully considered in an oral report, because the hearers have no escape from the speaker's plan: they must listen to the first part, first, and to the last part, last; and they must hear the whole of it. In a printed report, selection and order are still important, but for different reasons, inasmuch as the readers may run over printed pages rapidly if they wish to, skipping such details as they do not care to read, and even reading the last page first, if a summary is presented only at the end instead of also at the beginning. The preparation of an oral report demands critical care in the selection and definition of terms and in the phrasing of explanations; so that the right words may be immediately used; for the recall of a spoken word is impossible, and the correction of a wrong word by substituting another for it, is awkward and distracting. The preparation of a