This is fiendishly difficult to get right, and efforts to calculate this figure began, like so many mathematical techniques, as a matter of marginal, somewhat nerdish interest during the 1930s.
计算这个数字是极其困难的。在20世纪30年代,为之所付出的努力就像许多数学技术一样,只是一种边缘的、有点书呆子气的兴趣。