220 REPORT—1874. 
From the chart for 1866 it will be seen that in April of that year there 
was a number of small cyclones. The S.E. trade and N.W. monsoon were 
in collision for a considerable time, and several cyclonic eddies of short 
duration were formed. 
If we could obtain good values of the mass of air in motion and the velo- 
city of the wind, it would probably be found that the ratios of cyclonic 
energy were still greater than those of cyclonic area ; for the cyclones were 
much more violent in the years of maximum than in those of minimum sun- 
spot frequency. 
Assuming the mass to be nearly proportional to the area, and the velocity 
of the wind in a strong gale to be fifty-five miles, in a whole gale seventy 
miles, and in a hurricane eighty-five miles an hour, the amount of cyclonic 
energy in 1860 was about eighteen times greater than in 1856, the squares 
of the velocities being nearly three to five. 
Although the results are necessarily rough approximations, yet the fact 
that the number and violence of the cyclones of years of maximum sun-spot 
were far greater than in the years of minimum sun-spot is beyond all doubt. 
There is independent evidence of this, which any one may examine for him- 
self. When a great hurricane takes place in the Indian Ocean the disabled 
ships are obliged to put into the nearest port ; and the newspapers, in their 
‘“‘ Shipping Intelligence,” announce the arrivals of the vessels, the dates and 
localities of the bad weather, and the amount of damage sustained. 
For upwards of twenty years the ‘Commercial Gazette’ of Port Louis has 
published all arrivals of vessels and all maritime events which have been 
reported by them. Considering, then, the geographical position of Mauritius, 
a cyclone periodicity, if one exists, should be traceable in the “ Shipping 
Intelligence.” Now, from Table II., which gives the published reports for 
1856, 1860, and 1867, it will be seen that the number of storms and the 
damage sustained in 1856 and 1867 were insignificant compared with the 
long list of hurricanes and disasters in 1860. 
Table III. gives as complete a list of hurricanes and storms experienced 
in Mauritius as I have hitherto been enabled to prepare. The list comprises 
only such storms as, from the violence of the wind, committed considerable 
damage. Taking each maximum and minimum sun-spot year, and two years 
on each side of it, we get the following results :— 
Number of Number of 
Max. Years. Hurricanes, Min. Years. Hurricanes. 
GBS: APR ae 1 1723) |: Bee 
ZOO” cide nwee ler 1 U75L 1. SMe. dae 1 
L7G0G soe ee 1 Via |. «scene if 
(01 Dee erin ae if iy 5": SP eS it 
yagi ates sxc cnayapatoas Aes 1h GG) a's saiekan ee A 
NG awhinwsd « Feved ae 1 7 8G! ose ys igen 1 
NVISIS) peterateb te wisdom toes i 1300)... seek tee 1 
PZSGie oe eke «aie 1 5 }27, Sy Soy if 
PBUG  otenios «setae 1 _— 
ISLS » woth gets 1 Total cee 8 
1817+ Giese Pe 1 
SUB: | ects eters 1 
MELO ek. sors Fite at 2 
Lc) Pe Sa er ae es 1 
DO waphosye Salsyereneth 1 
SEGRE: fils aitia e060 ss 1 
TOAS Pei. etsas 1 
Total... Lo 
