AT KEW OBSERVATORY, 1890 TO 1900. 
243 
in a day which with its three preceding days showed no sunspot. In October, 1890, 
the largest spotted area encountered on the five days of largest range, or during the 
4-day periods preceding them was only 120, whereas the mean of the sunspot areas 
for the four days of smallest range and the 4-day periods preceding them were as 
follows:— 
Day .... 
n. 
71-1. 
n — 2. 
n- 3. 
n- 4. 
Sunspot area .... 
1095 
1089 
970 
714 
597 
In this instance the ranges in the two cases were widely different, the means being 
22 /- 9 for the five days of largest range, and only 6 /- 7 for the four days of least range. 
February 1 , 1893, was a “quiet” day, and had a range 3' less than that on any 
other day of the month. It had, however, the largest spot area of the month, and 
the four immediately preceding days in January had all spot areas larger than that of 
any single day in February. 
In April, 1894, the two days of largest range were the days of least spot area for 
the month, and the four preceding days in each case were included in the group of 
ten days of least spot area. 
In November, 1895, not one of the nine days of largest range came into the group 
of ten days of largest spot area, and the day of the absolutely largest range was the 
day of absolutely least spot area. 
In February, 1896, the two days of largest spot area were both “ quiet” days, and 
had the smallest ranges of any in the month. 
In October, 1896, not one of the nine days of largest range—four of them dis¬ 
turbed—nor of the four days preceding them came into the group of ten days of 
largest spot area. 
In October, 1897, the day of largest range but one—itself a disturbed day—and 
the four previous days were all free from spots, though only three other days in the 
month were similarly situated. 
During February, 1899, there were three “ disturbed” days—one showing a range 
of 45'—and all three were free from any sunspot, though sunspots occurred on 17 
days of the month. 
In 1900 the sunspot area was absolutely nil from November 24 to December 31. 
December is the month of minimum range, and so the amplitude of the regular 
diurnal variation naturally would vary but little throughout the month. Thus if an 
intimate connection of any kind—possessing a time lag of any length up to six days— 
really existed between range and sunspot area, what we would have expected to find 
would have been a nearly constant daily range. What actually did happen is shown 
by the following figures :— 
2 i 2 
