LJTJNGMAN — SECULAR PERIODICITY OF HERRIXG FISHERIES. 501 



From this series of fifty-five-and-a-half-years' periods, it will be seen, 

 first, that large numbers of sea-herrings came to the coast of Bohus liin 

 daring every other one of these periods, producing good fisheries and 

 consequent wealth; second, that unusually good fishery periods changed 

 about with less good ones. Thus, the herring fisheries during the fif- 

 teenth and seventeenth centuries were far less important, and probably did 

 not last as long as those of the fourteenth, sixteenth, and eighteenth cent- 

 uries. In the above series this change has been indicated by putting some 

 of the figures in heavy-faced type. The Bohus liin herring-fishery cycles 

 seem therefore to correspond exactly with Professor Fritz's great Xorth- 

 ern lights' periods of about two hundred and twenty-five years each, and 

 to include one very good and one less good fishery period, as well as two 

 intermediate periods when the sea-herrings staid away from the coast. 

 From what we know concerning our periodical herring fisheries, it ap- 

 pears that the interval between the good fisheries of the fourteenth cent- 

 ury and those of the sixteenth century was longer than the interval 

 between those of the sixteenth and eighteenth centuries, and that the 

 interval between the good fisheries of the thirteenth and fourteenth 

 centuries, and between those of the seventeenth and eighteenth cent- 

 uries was probably shorter than might be supposed, for between the 

 two last mentioned it is said to have been only fifty years. 3 Such differ- 

 ences in the length of the periods are. also known in the periods of the 

 solar spots, those whose average length is 11.11 years often being only 

 eight to fifteen years long. It is probable, however, that these differ- 

 ences indicate still longer periods, during which they recur with a cer- 

 tain regularity. Thus, in the series given above, the differences follow- 

 ing each other make it probable that there is a larger period of four 

 hundred and forty-four and one-half years, with which the former rich 

 herring fisheries on the coast of Skane and Zealand may correspond. 



It is also a strange phenomenon that the most flourishing fisheries of 

 a herring fishery period coincide with or occur about the same time with 

 the liveliest formation of solar spots, and the most numerous northern » 

 lights during a fifty-five-and-a-half-years' period, 4 and that a peculiar 



3 0. Luxdbkck., Antekningar rorande Boluisliinslca Fiskericrna i synnerhet Sillfisket. 

 Goteborg, 1832, p. 36. 



The fact that the interval between two Bohns liin herring-fishery periods is as high as 

 seventy years may be explained by the small alternating fishery periods having only 

 occupied a part of the fifty-five-and-a-half-years' period; even the unusually rich 

 herring-fishery periods do not seem to have always occupied the whole of that period, 

 although in some cases, e. g., during the eighteenth century they may have been even 

 a few years longer. 



4 By comparing the different statistical data regarding the revenue derived by tho 

 government from the herring fisheries during the present and the last century with 

 Wolff's relative figures, I have not been able to find any very striking coincidence be- 

 tween the occurrence of solar spots and good fisheries; but it seems that, e. g., in the 

 Scotch herring fisheries the best fisheries occur generally two to five years after the 

 maximum number of solar spots, and the smallest, one to three years after their min- 

 imum number. A more striking coincidence may possibly be shown between the 



