A practical method of harmonic analysis

Object.¿To provide a self-explanatory schedule for routine work. Method.¿Sums and differences of observations are taken (as in the late Professor S. P. Thompson´s method and others). A sufficient number of values are solved in general terms, so that working an example is reduced to filling in values in known equations. This work is expedited very materially by means of the schedule. Nothing but a slide rule is necessary, and the actual calculations can be carried out by persons with no great knowledge of mathematics. Results.¿An example has been worked out up to the 17th harmonic in 50 minutes, thus comparing favourably in this respect with other methods. Furthermore, the results are given in the form E sin (¿ + ¿), which is more useful than EA sin ¿ + EB COS ¿. In cases where harmonics higher than the 17th are present in appreciable magnitude, an increased accuracy in the analysis is obtained for a given number of ordinates.