THE METEOROLOGY. AND CLIMATE OF PLYMOUTH. 429 
between observers who otherwise are as careful as it is in man’s 
power to be. If any one should feel inclined to compare his 
observations with mine, he should endeavour to place his instru- 
ments under similar circumstances, or his comparisons will lose their 
value. My maximum and minimum thermometers are by Negretti 
and Zambra. They face due north, and are placed in a screen 
about 4 feet from the ground and 1 foot from the wall in my office ; 
thus no sun ever falls on the screen, and there is free access for air 
to play all round them. ‘The mean temperature of Plymouth I 
have found to be 51°62° F. This mean would obviously be best 
obtained by recording for a very long period twenty-four hourly 
observations, and taking their average ; but Buchan, the secretary 
of the Scottish Meteorological Society, has shown that the arith- 
metic mean between the maximum and minimum for every day in 
the year is too great only by a small fraction of a degree; and this 
is the method I have adopted. The latter parts of the months of 
April and October give nearly the same means as for the year. Our 
hottest months are July and August, when the averages are 62°97° 
and 62°50° respectively, thus showing that July has the advantage. 
Our coldest months are January and December, when the averages 
are 42°34° F’. and 42°63° F. respectively, thus showing that January 
has the least temperature. 
Like every other place, we have some extreme readings; but 
these in Plymouth, as in all the south-west district, are compara- 
tively rare. The maximum temperature in the shade I have ever 
recorded was on 27th June, 1866, when it showed 93° F. ; the mini- 
mum was 14° F., on 27th December, 1869. I have many instances 
of the temperature reaching from 85° to 90°. I find the maximum 
for the day to be generally from 2°30 to 3 p.m. ; but the time is so 
modified by the seasons, by clouds, and by change of wind, that I 
have often found the minimum temperature to be in the day and 
the maximum to be in the night. On some days the maximum 
has not risen to the freezing-point, the last time being on the 
22nd January of this year (1881), The minimum temperature at 
times has been far above the average monthly temperature, as on 
August 27th, 1869, when the minimum reached only 67° F. The mean 
annual range—i.e. the range from the hottest month, July, to the 
coldest month, January—is 20°63°, whilst the difference between 
the average maximum and minimum for the year is only 13:13°. 
Some years we have more than double the annual range, as for 
