The chart brings out this information very clearly. Since the superintendent can take the matter up with the various foremen before noon of the day after the work was completed, the foremen soon get the feeling that the superintendent knows what the cost should be, and, if anything happens to prevent work being done cheaply and quickly, the foremen are likely to report the conditions at once to see if assistance can be given them so as to keep the cost low.

After the superintendent has seen the pin boards each morning, the long pins represented by numbered dots in Fig. 159 are removed and in their places are put the short glass-head pins having shanks so short that the pins may be pushed into the straw-board until the head of the pin touches the co-ordinate paper. The pins are then quite secure, and the boards may be worked upon and handled month after month without danger of the pins becoming lost from the boards. The ordinary type of tall pins or tacks used with wooden boards would not be at all satisfactory for this class of work, as it would be impossible to work with such boards containing thousands of tacks without knocking the tacks loose, so that they would be in a continuous process of becoming lost -- much to the detriment of accuracy and to the disgust of a cost clerk. The short glass-head pins pushed in until the heads touch are very convenient and they give a thoroughly accurate record.