248 
A SHORT PERIOD OF SOLAR AND 
METEOROLOGICAL CHANGES} 
I N continuation of the inquiries referred to in a former 
paper on Indian rainfall and solar activity,” attention 
has more recently been devoted to an examination of 
the variations of pressure over the Indian and other 
areas. 
(1) It is well known that in India during the summer 
months (April to September) and during the winter 
months (October to March) low and high pressures re- 
spectively prevail. In the case of the latter, the pressure 
is found to exhibit very remarkable and definite varia- 
tions, and is in excess every three and a half years on 
the average, while at these times of excess of high pres- 
sure the low pressure during the other six months of the 
year is deficient ; so that every three and a half years or 
so the high pressure becomes higher and the low pressure 
is not so low as usual. 
(2) Further, this short-period variation which appears 
in the mean variation of pressure over the whole of India 
is as well defined in the mean values for individual 
1600 1870-0 16800 1099-0 1900.0 
Ci Cee es seeded eednans 
3000 
SUNSPOTS. i000 
1000 
° 
WIDENED LINE 
60 
CROSSINGS, 
+20 
MEAN LATITUDE+1I0 
or 
SUNSPOTS., 
oe 
LATITUDE oe 
TOTAL 
SPOTTEO AREA. _ 
NUMBER or 
PROMINENCES. 
PRESSURE. 
BOMBAY. —-ga00 
[ocr.— MARL] 
29-8600 
PRESSURE. 600 
BOMBAY. 
Cara.— seer.) t 
29-7000 ' 
Hier elaly leihisiyatiess unig iotefeie gisnepsteseinecxda ip aisiAleghelainay | ataxe 
1860-0 1870-0 1880-0 1620-0 1900-0 
HiGaxs 
stations such as Bombay (Fig. 1, Curve F), Calcutta, 
Madras, Nagpur, &c. 
(3) The view that the variation of pressure in question 
over India and its neighbourhood is not due to local 
causes, but is produced by some external, or extra- 
terrestrial action, is considerably strengthened by an 
examination of the pressure curve of a very distant 
station such as Cordoba. Dealing with the pressures 
at Cordoba during the high-pressure six months, April 
to September, the curve (Fig. 2, Curves F and E) repre- 
senting the variation from the mean from year to year is 
exactly the z7verse of the curve representing the Bombay 
and other Indian pressures for the same months over the 
same period of time. The cause, therefore, which raises 
the mean value for the low-pressure months over the 
1**On Some Phenomena which Suggest a Short Period of Solar and 
Meteorological Changes,” by Sir Norman Lockyer, K.C.B., F.R.S., and 
William J. S. Lockyer, M.A., Ph.D., F.R.A.S. (Read before the Royal 
Society, June 19.) 
aa On Solar Changes of Temperature and Variations in Rainfall in the 
Region Surrounding the Indian Ocean” (Roy. Soc. Proc. vol. Ixvii. p. 409). 
NO. 1706, VOL. 66] 
NATURE 
[JuLY 10, 1902 
Indian area would appear to lower the mean value of 
high-pressure months at Cordoba simultaneously. In 
fact we have a see-saw. 
(4) Further investigation shows that not only do the 
pressures of practically the whole Indian area exhibit 
variations from year to year which present very similar 
features, but that this is the case with other large areas, 
Thus, for instance, it is found that the yearly mean 
pressures for Brussels, Bremen, Oxford, Valencia and 
Aberdeen (the only pressures that have been at present 
examined) are all remarkably similar in their variations 
from year to year ; and it might almost be said that one 
curve representing the variations from the normal would 
approximately define the pressures at all these places. 
The probable extra-terrestrial origin of these short- 
period variations led to a detailed examination of the 
records of the phenomena connected with solar spots and 
prominences, with a view of seeing whether similar vari- 
ations, indicating changes in the solar activity, could be 
detected. 
(5) A preliminary reduction of the Italian observations 
1900-0 1870-0 1880-0 7890-0 1900-0 
Vebve vedere eb enerdeneedeveedeerrtane 
' ' 
PRESSURE 850> 
(veanux mean) 9359- 
e10+ 
OME AYE Es 
RAINFALL 7*- 
(CYBARLY mean) 53~ 
42> 
MADRAS 3." 
RAINFALL “~ 
(eerr— pec.) 49° 
1A STATIONS §=7°- 
in a2- 
IGEVEONI)) 2A) 
RAINFALL “°° 
(May—oeT) 2° 
MALABAR !00- 
80- 
PRESSURE 20-7000 ~ 
(APR~SEPT) — 200- | 
BOMBAY 00- 
(SCALE INVERTID) 600 - 
PRESSURE 7-00- 
(APR —8EPT) 6 g0- 
CORDOBA, 2 ¢.00- 
1860-0 1490-0 1900-0 
we ’ 
4860-0 1870-0 
Fic. 2. 
of prominences observed on the sun’s limb since 1871 
was first undertaken. The result of this inquiry indicates 
that, in addition to the main epochs of maximum and 
minimum of prominences which coincide in time with 
those of maximum and minimum of the total spotted 
area, there are prominent subsidiary maxima and minima 
having a similar short period, and also coinciding in 
time (Fig. 1, Curve E), 
(6) Although these subsidiary prominence pulses are 
not distinctly duplicated in the curve representing the 
spotted area of the solar surface, it is to be noted that 
corresponding pulses are -indicated in the curves which 
represent the change of latitude of spotted area from 
year to year ; and in each case an increase in prominence 
activity is associated with a decrease of latitude of the 
spotted area (Fig. 1, Curves C and D). 
(7) A comparison of these solar data with those already 
referred to relating to terrestrial pressures suggests 
that these simultaneous outbursts of prominences and 
changes of the latitudes in which the spots occur about 
ee 
