This leads us to the last, and, in some respects, the most singular suggestion respecting solar influence on mundane events--the idea, namely, that commercial crises synchronise with the sun-spot period, occurring near the time when spots are least in size and fewest in number; or, as Professor Jevons (to whom the definite enunciation of this theory is due) poetically presents the matter, that from 'the sun, which is truly "of this great world both eye and soul," we derive our strength and our weakness, our success and our failure, our elation in commercial mania, and our despondency and ruin in commercial collapse.' We have better opportunities of dealing with this theory than with the others, for we have records of commercial matters extending as far back as the beginning of the eighteenth century. In fact, we have better evidence than Professor Jevons seems to have supposed, for whereas in his discussion of the matter he considers only the probable average of the sun-spot period, we know approximately the epochs themselves at which the _maxima_ and _minima_ of sun spots have occurred since the year 1700. The evidence as presented by Professor Jevons is very striking, though when examined in detail it is rather disappointing. He presents the whole series of decennial crises as follows:--1701? (such query marks are his own), 1711, 1721, 1731-32, 1742 (?), 1752 (?), 1763, 1772-73, 1783, 1793, 1804-5 (?), 1815, 1825, 1836-9 (1837 in the United States), 1847, 1857, 1866 and 1878. The average interval comes out 10.466 years, showing, as Jevons points out, 'almost perfect coincidence with Brown's estimate of the average sun-spot period.' Let us see, however, whether these dates correspond so closely with the years of _minimum_ spot-frequency as to remove all doubt. Taking 5-1/4 years as the average interval between _maximum_ and _minimum_ sun-spot frequency, we should like to find every crisis occurring within a year or so on either side of the _minimum_ though we should prefer perhaps to find the crisis always following the time of fewest sun-spots, as this would more directly show the depressing effect of a spotless sun. No crisis ought to occur within a year or so of _maximum_ solar disturbance; for that, it should seem, would be fatal to the suggested theory. Taking the commercial crises in order, and comparing them with the known (or approximately known) epochs of _maximum_ and _minimum_ spot frequency, we obtain the following results (we italicize numbers or results unfavourable to the theory):--The doubtful crisis of 1701 followed a spot _minimum_ by _three_ years; the crisis of 1711 preceded a _minimum_ by one year; that of 1721 preceded a _minimum_ by two years; 1731-32, preceded a _minimum_ by one year; 1742 preceded a _minimum_ by _three_ years; 1752 followed a _maximum_ by _two_ years; 1763 followed a _maximum_ by _a year and a half_; 1772-73 came _midway_ between a _maximum_ and a _minimum_; 1783 preceded a _minimum_ by