26,162. Norman, H. Nov. 14. Tabular and logarithmic calculators.-Apparatus for determining the times required for t h e manufacture o f cardboard boxes of various sizes comprises a scale e, f representing in inches the sums of two dimensions of the boxes, and a scale c, g representing the third dimension. The intersection of co-ordinates corresponding to these values is denoted by a letter, similar letters representing virtually curves of equal times derived from experimental data. These scales are mounted on a rotatable disk b, the edge of which bears a logarithmic scale of " time - values " : the fixed base a is graduated as shown. The apparatus must first be standardized for use with a given type of box by ascertaining experimentally the times required to make one or two such boxes of a certain size or sizes. The letter corresponding to the dimensions of the box is found in the table, and the disk b is adjusted so that the actual time-value experimentally determined and given on the inner arcual scale registers with the given letter on the outer scale. Time-values of boxes of different sizes but of the same type can then be found from the arcual scales after the letter corresponding to their dimensions has been ascertained from the tables e f, e y.