Let t be the position of any term in the aeries and/(j) the frequency corresponding, then the following table (page 376) explains itself. Consider the line opposite tho first term and we notice that the Bum of the series is given by the first summation Si and that the second which we will call &, gives the first moment of the whole distribution about a vertical through a point situated at unit distance before the point corresponding to /(I). Still considering only the first line we see that St

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... ives each function multiplied by moment. Similarly S t gives S t > A numerical example is as follows. where »' is written for the rough , and henoe TABLE IL Function