Oct. 9, 1873 | 
NATURE ; 
495 
upon the surface of the moving body. The moying body is like 
the train, and the rays of light and heat are similar to individuals 
entering the train from a stratum of ether at rest, and leaving 
the train into a stratum of ether at rest again, each probably trans- 
muting into heat a certain small portion of the visible motion of 
the train as it were by a species of friction, Of course the in- 
tensity of such an influence would depend upon the intensity of 
the rays of light and heat. Now it matters not what the par- 
ticular kind of motion be which constitutes this train—we 
may assert that all directed motion will suffer from such a cause, 
and possibly according to the same laws. Visible motion, such 
as that of a rotating disc, or of a meteor, is of course one form 
of such motion; but a current of electricity or of heat may 
equally represent some form of directed motion. In fine, we 
may perhaps suppose that all forms of directed motion are re- 
sisted by this peculiar influence, which evidently depends upon 
what we may term the temperature of the ether, or at least upon 
the intensity of those vibrations which the ether transmits. 
On a Periodicity of Cyclones and Rainfall in connection with 
the Sunspot Periodicity, by Charles Meldrum. 
At the Brighton meeting (1872) it was stated that the cyclones 
of the Indian Ocean between the Equator and lat. 25° S., were 
much more frequent during the maxima than during the minima 
sunspot years, Since that time the subject has been more fully 
examined, and I now beg to present a catalogue of all the 
cyclones known to have occurred during the last twenty-six 
years. The Tables given last year only contained cyclones of 
sufficient violence to dismast or otherwise disable vessels at sea, 
whereas the accompanying Catalogue gives all the cyclones of 
force 9 to 12, that is, ‘‘strong gale” to “*hurricane.” 
The number of cyclones for each year from 1847 to 1873, is 
as follows :— 
ig 
Years. 
canes. 
No. of Storms. 
Cyclones. 
No. of 
Whole Gales 
No. of Stron, 
Gales. 
Total No. of 
No. of Cyclones 
in Max. and 
Min. Periods. 
No.of Hurri- 
~ 
—~ 
b 
cea) 
— 
- 
we 
5 
8 
° 
8 
7 
8 
8 
4 
5 
4 
4 
9 
39 
21 
{ 
WerWOiNWNHKWeH HE NND DH HH OOM O00 
OXWLNOOHOOHNHNORNOHOOHOOONOO 
POW NWW OR NNO PUNTWWD HOW MPR w OM 
UAND EA DPRR HON HOHNE NH HON HH ONWNNO 
Ay 
The observations for the years 1847-1850, are probably not so 
complete as those for the subsequent years during which the 
Meteorological Society of Mauritius made it a special duty to 
~ collect storm statistics. Still it is evident that not only the years 
1860 and 1872, but also the year 1848, were remarkable both 
for the number and violence of cyclones, while the years 1856 
and 1857 were quite the reverse. By taking the number of 
cyclones in each maximum and minimum sunspot year, and in 
each year on either side of them, so as to form maxima and 
minima periods of three years each, we obtain the results given 
in the last column of the above table, showing that during the 
maxima periods 1848-1850, and 1859-1861, the number of 
cyclones was 65, whereas in the minima periods 1855-1857, and 
1866-1868, it was only 34, or little more than one half. In 1856, 
there was only one hurricane of small extent, and in 1867, no hur- 
ricane at all. Indeed it is doubtful whether several of the cyclones 
in those years classed under “ storms,” should not have been put 
down in the columns of ‘‘ whole gales” and “ strong gales.” 
As, during the last twenty-two years, information respecting 
the hurricanes of the Indian Ocean has been carefully and sys- 
tematically collected and tabulated, I believe that the results 
now given are substantially correct, and it seems to me that they 
point unmistakeably to a close connection betwen sunspots, or 
solar cyclones, and terrestrial cyclones, or what might be called 
earth-spots, by an observer, on anothe. planet. : 
Most of the severest cyclones have already been traced, ani 
the others will also be traced. When this shall have been done, 
an attempt will be made to express numerically the amount of 
cyclonic area and cyclonic force for each year. The catalogue 
gives little more than the number of cyclones, but from what is 
already known, there is little doubt that their extent and force 
were also far greater in the maxima than minima years, 
Being desirous of extending the investigation as far back as 
possible I have been examining the lists of former hurricanes, 
and it is interesting to find that the evidence from this source 
strongly corroborates the correctness of the conclusions deduced 
from the observations of the last twenty-six years. From a 
‘chronological table” published in the ‘* Mauritius Almanack ” 
of 1869, we obtain the following list of Mauritius hurricanes :— 
r No. of 
Years janpicaes 
1731 
ET Meee 
1760 .. 
1766 .. 
DT .. 
DTI. on 
1773 ++ 
1786 .. 
1806 .. 
1807 .. oe 
BOG peers Saat 0c a2 sady es 
- 
mee ete 
Probably the above list gives only the hurricanes that were re- 
markable from their destructive effects in the island ; and much 
stress should not be laid on observations taken at a single locality. 
But it is rather suggestive that out of the twenty-four hurricanes 
mentiened, seventeen fall within, or very nearly within, 
maxima sun-spot periods, and only seven within minima 
periods. Thus :— 
Max. No.of Min. No. of 
Years hurricanes Years hurricanes 
MUPENY cate conai a's sis Cues chiens I TA Ore 
1771 SA. on 
1772 Raeeocdeea ee sewt ss 3 T7600. 
1773 1824 ... 
MOG esas ce Oaewcectaccensas I 1834 ... 2 
1806 } (SE bee SORA oa Pe 
1807 j Se asertecrsrensepees 3 
1815 ) PDORAR reacts apacenee 7 
1818 ae = 
1819 j 
1828 si 
el ae 
DI eas ons wonneae I 
1848 
840 | a 2 
V0 ee ee 17 
The same “ chronological table” contains the following re- 
marks :— 1760, Dec. 1, ‘‘ Meteorological Phenomena,” 1815, 
Feb. 5, “ Meteorological Phenomena.” —I have not ascertained 
what these phenomena were ; but it is not improbable that they 
were auroras. The auroraof the 4th Feb., 1872, was described 
in the newspapers as a phénoméne météorologique. 
Baron Grant, in his History of Mauritius, p. 194, regrets the 
destruction of the woods near Port Louis, because, he says, the 
town was thereby ‘‘ exposed to the violence of the winds, as well 
