TRANSACTIONS OF THE SECTIONS. 



57 



For the present, I wish merely to call atteution to the subject, in order that the 

 connexion which I think exists between sun-spot-frequency and cvclone-frequency 

 may be either verified or refuted by past or future observation, "it appears to me 

 that there is more tlian a mere coincidence as to time. There are three maxima 

 and two minima epochs of cyclone-frequency corresponding nearly, if not entirely, 

 with similar sun-spot epochs. 



To examine the matter fully, it would be necessary not only to know the number 

 of cyclones in each year, but also the extent and duration of each, and tlie force of 

 the wnid. If we could thus get an expression for the annual amount of cyclonic 

 energy, and could show that it varied directly as the amount of sun-spots, a con- 

 nexion would be established. One violent hurricane, which lasted ten days and 

 passed over thousands of miles, might have more value than half a dozen smaller 

 and short-lived ones. However, having traced a large number of the cyclones in 

 question, I have no doubt that the years of greatest cyclone-frequency were o-ene- 

 rally, if not always, the years of greatest cyclone-energy ; and that the number of 

 cyclones in a year is a fair expression of the cyclonic activity for tliat year. 



Now, taking the maxima and minima epochs of the sun-spot period and one year 

 on each side of them, and comparing the number of cyclones in these three-year 

 periods, we get the following results : — ■ 



Maxima 



Minima 



Maxima 



Minima 



Maxima 



Number of 

 Cyclones in 

 Years. each year. 



11847 4") 



0848 gI ... 



(1849 5 1 



(185o 4) 



\ 1856 1 . . . 



1 1857 .3 j 



(1859 5) 



\ I860 8 i ... 



( 1861 8 1 



1 1868 51 



^1387 21 , 



1868 2 



Total num- 

 ber of 

 Cyclones, 



.3] 

 4 



15 



21 



14 



Taking two years on each side of the solar-spot epochs, we o^et :- 



Minima 



Maxima 



Minima 



Years. 

 ■ 1854 

 1855 

 1856 

 1857 

 1858 



1858 

 1859 

 1860 

 1861 

 1862 



1865 

 1866 

 1867 

 1868 

 1869 



A'lunber 

 of Cyclones. 

 .... 41 



::::U.. 



.... 4 

 .... 5 



1 



8 



7 



r 



ij 



Total 

 number. 



15 



32 



15 



