THE METEOROLOGY AND CLIMATE OF PLYMOUTH. 435 
or by about one-thirtieth. This would give 43°561 inches as the 
correct average rainfall, and 189:12 as the average number of 
rainy days for Plymouth. The humidity of a district should be 
judged more by the number of rainy days than by the quantity of 
rain which falls ; because fine rain falling for several consecutive 
days not amounting to nearly as much as a single short heavy 
shower, will render a climate more moist than another where rain 
falls heavily for short periods; and in Plymouth we often get 
drizzling rain lasting for hours, or perhaps for days, and yet the 
rainfall for that time is comparatively small. Although so near 
the sea, and situate, as I have said, in the path of the Counter 
Trades, we sometimes, though rarely, experience a want of rain. 
From March 18th to July 2nd, 1870, if we omit a thunder-shower 
on the 12th May, only 1°3 inch of rain fell in 106 days; but on 
the average we have rain enough to measure, that is, amounting to 
‘Ol inch, every other day, to the amount of less than one-twentieth 
of an inch on 59 days in the year, and to the amount of less than 
one-tenth of an inch 88 days in the year. In the past five years 
there have been twenty-four weeks (from Sunday to Saturday) in 
which I have collected no rain. It happens in Plymouth that the 
month of greatest rainfall, 43 inches, in January, corresponds with 
the greatest number of rainy days, viz, 192; but the month of 
least rainfall, June, 1? inch, does not correspond with the least 
number of rainy days. September stands fifth in order of rainy 
days, but is second in order of rainfall; hence, if we neglect 
summer thunder-showers, our heaviest rains must occur in that 
month. 
Winps.—Again we must enlist the Counter Trades into our 
service to explain the prevalence of south-westerly winds in Ply- 
mouth, and on all western seaboards in the North Temperate Zone ; 
but from our sheltered position we do not feel the full force of the 
wind from any direction. During the sixteen complete years I 
have kept a meteorological register in Plymouth, on 1252 mornings 
the wind was from north-by-east to east, 1032 mornings from east- 
by-south to south, 1700 mornings from south-by-west to west, 
1348 mornings from west-by-north to north, whilst on 512 morn- 
ings there have been calms. These numbers give 21°42 per cent. 
from the north-east quadrant, 17°66 per cent. from the south-east 
quadrant, 29°09 per cent. from the south-west quadrant, 23-07 per 
VOL. VII. 2 F 
