Our attention was called to Fourier's Series in a discussion on engineering subjects with Professor William E. Dalby, F.R.S., the Dean of the City and Guilds Central Technical College, London University. Judging by the use made of Fourier's Series in engineering problems, it seemed possible that it might apply equally well to actuarial and statistical science.

Sir George F. Hardy in his course of lectures on the Construction and Graduation of Tables of Mortality (p. 35) stated “A second test tha t has occasionally been applied when the graduation has been effected by means of a formula is that of making the sums of the squares of the deviations a minimum … This method, known as the method of Least Squares, is used very generally in connection with measurements in astronomy and other physical sciences …”