=301. Vertical, and Loose=, _versus_ =Other Methods.=--Any rigid method of filing becomes confused and time-wasting. For example, the old method for correspondence sent out was to copy it in a letter-book which was equipped with a thumb-index. As all letters so copied were placed in the book in chronological order, it necessarily happened that correspondence with a given person or on a given subject was found in several separate places in the book; and, although the letters received which occasioned the correspondence could be pasted into the letter-book against the replies, no connected view of the correspondence could be gained without several references. The letter-book method served its purpose for a long time, and has been preserved owing to the conservatism which is a British characteristic and to fear of loss, misplacement, or inaccurate record being made. Experience proves, however, that loss and misplacement can easily be prevented, and accurate record of letters is equally possible, when filing by flexible methods is used. Moreover, the principle of classification--alphabetical or subject--is the foundation of successful filing which admits of rapid reference and completeness; for it is beyond question desirable that all correspondence, documents, etc., relating to any given matter, should be kept in one place only. For example, the bookbinding transactions of a library involve correspondence with several bookbinders, specifications, instructions, orders, incidental correspondence respecting defects, errors, etc.--and all this material should come together for the simple reason that it is used together. To ensure this the material must be filed individually as a general rule; that is to say, in such a way that additional material can be inserted. There are various methods: the Stolzenberg file, for instance, and other files which resemble it. These are generally folders of stout manilla, having two flexible prongs inside at the fold which penetrate and fold over the margins of the papers and so hold them in place; and when an insertion is made the prongs are lifted and the new paper fitted into position. More recent is loose filing in folders in which the material is not secured in any way, and insertions are therefore possible without obstruction of any kind. All folders are filed in drawers, in cabinets as a rule, and the average office desk is now equipped with drawers for vertical filing. An illustration of a folder and filing cabinet will show better than much description what we have in mind (Figs. 114, 115). [Illustration: FIG. 115.--A Drawer of a Correspondence Filing Cabinet.] In these folders correspondence and other documents are filed together with the carbon copies of replies. The carbon copy of a letter is, of course, an exact facsimile of it made at the one original operation of writing or typing the letter; it is thus an exact record, and additions or corrections are easily visible.