184 
FIFTH REPORT— 1835 , 
I have thought it worth while to allude to this coincidence, as 
it shows the care with which the respective observations have 
been made. I find, however, on comparing the registers for 
particular hours, that some greater differences arise, as might be 
anticipated from the different local circumstances under which 
the thermometers were placed 3 the thermometer in the Dockyard 
is from its free position less exposed to the influence of local 
h?at than that formerly employed at the Artillery Barracks. It 
is not, I believe, in any case desirable to place a thermometer 
so close to the roof of a low building, upon which the sun’s rays 
in summer are powerfully acting, and within which the ordinary 
avocations of domestic life are carried on; it seems, however, in 
this case to have been unavoidable. This is, perhaps, alone suf¬ 
ficient to account for the generally small increase of temperature 
at the Artillery Square shown in the above tables. In the mode 
of exposure of the thermometer at the Dockyard, I have en¬ 
deavoured, so far as possible, to fulfill the conditions incidental 
to the exposure of a thermometer suspended in free space under 
the shade of a tree, avoiding at the same time the effects of hu¬ 
midity. This is, I believe, by far the most accurate method of 
observing atmospheric temperature. 
The register was commenced on the first day of May, 1832, 
and has been continued hourly every day and night since, without 
any intermission. The observations have been fairly copied and 
reduced up to May, 1835*, so that I am enabled to present the 
Association with the results of at least two complete years, be¬ 
ginning with January, 1833, and ending with December, 1834. 
These full years have been selected with a view to an immediate 
comparison with the results of the hourly register carried on at 
Leith in the years 1824 and 1825: the observations have been 
arranged and discussed according to the method resorted to by 
Sir David Brewster in his capital paper on the Leith Observa¬ 
tions in the 10 th vol. of the Transactions of the Royal Society 
of Edinburgh. 
The months of December, January, and February are taken 
as winter months; March, April, May, months of spring; 
June, July, August, summer months; September, October, and 
November autumnal months. The six months of summer be¬ 
gin with April and end with September, both inclusive; the six 
* Mr. T. A. Southwood, of the Classical and Mathematical School at Mount 
Wise, Devonport, has vei'y kindly afforded me his valuable assistance in discuss¬ 
ing the observations. 
Mr. Hoskyn also and Mr. G. Harvey have contributed much to advance the 
work. The cooperation of these gentlemen has been of great consequence, since 
the labour of copying and reducing above twenty-six thousand observations is 
by no means small, as is well known to every one engaged in a similar under¬ 
taking. 
