The method of laying the tracings flat in drawers was abandoned, and they are now filed in cardboard tubes, thirty inches long and four inches in diameter, with tightly fitting covers of the same material. Each tube has on the cover its index number and a type-written list of the tracings it contains. The tracings are rolled in small bunches of four or five, and each bunch is held to small diameter with a rubber band, to which is attached a tag giving the number and title of each of the sheets contained in the roll. Five rolls are placed in each tube, making a total of from twenty to twenty-five tracings per tube. The tracings should not be rolled so closely that they will become creased.

An index is kept of all tubes, giving their numbers and the titles of the drawings contained in each; and there is in addition an alphabetical index of the drawings.

The tubes are set in cases With their covers exposed, and are so arranged that any tube can be easily reached or removed from the case if necessary.

Copies of all shop-drawings are also kept on file for reference. These are put in larger tubes, and as there is never any necessity for separating a set, as is the case with the tracings, each set is bound together when complete. The shop-drawings are all included in the two indices.

The specifications and calculations are kept in filing cases prepared especially for them, and both are indexed. These cases consist of a series of small shelves about one and a half inches apart, each shelf being numbered.

When a set of calculations is complete, the sheets are all bound together in one book with removable fastenings, so that they can be easily separated when it is necessary to distribute them among several draftsmen. These sets are all numbered with the numbers of the shelves on which they are to be filed.

In indexing all work every article should be indexed under as many headings as practicable.