Discussion at Spring convention: Mississippi river crossing of crystal city transmission line

St. Louis, Mo., April 14, 1925 J. S. Martin (communicated after adjournment): I have been especially interested in the authors´ methods of calculation of the sags required in the wire, as this is a subject of which I have made considerable study. In the proceedings of the Engineering Society of Western Pennsylvania for November 1922, I published a tabular method of calculating sag including a set of tables giving the functions of the catenary in the same manner that the ordinary trigonometrical tables give the functions of the circle. By means of these tables the sag required for any span and any wire can be quickly and accurately determined when the span is level. For the calculation of spans on the slope, the writer has resorted to an approximate method which gives results as close as the work of sagging can be done in the field and in nearly all cases the slight error is on the safe side.