572 MR. GLAISHER ON THE THERMOMETRICAL OBSERVATIONS TAKEN AT 
By taking the means of the differences of the results, we find that the reading of 
the thermometer in air at the Apartments of the Royal Society in 
January was higher than at Lyndon by .... TO 
February was higher than at Lyndon by ... . 0*8 
March was higher than at Lyndon by 0*8 
April was lower than at Lyndon by 0'2 
May was lower than at Lyndon by 0'6 
June was lower than at Lyndon by 1'7 
July was lower than at Lyndon by ..... . I'O 
August was higher than at Lyndon by less than . 0‘1 
September was higher than at Lyndon by . . . 0*4 
October was higher than at Lyndon by . . . . I’O 
November was higher than at Lyndon by. . . . LO 
December was higher than at Lyndon by. . . . 1'6 
Determination of the Mean Temperature of each month at the Apartments of the 
Royal Society for those months ivhen no observations were made there. 
By applying the above numbers to those in Table VIII. when no observations were 
taken at the Apartments of the Royal Society, the following Table is formed : — 
Table X. — Showing the approximate mean monthly temperature of the Air at the 
Apartments of the Royal Society. 
Year. 
Approximate mean temperature of the air. 
January. 
Feb. 
March. 
April. 
May. 
June. 
July. 
August. 
Sept. 
October. 
Nov. 
Dec. 
1 
O 
O 
O 
O 
0 _ 
O 
^0 
O 
O 
O 
O 
O 
1771. 
31-5 
34-8 
35-8 
39-8 
55*6 
54-9 
60-5 
59-7 
53*1 
48-5 
42-2 
42-8 
1772. 
33*8 
35’6 
39-6 
43-3 
49*7 
60-3 
61-0 
61-0 
56-1 
53-7 
44-7 
40-9 
1773. 
38-5 
36*5 
42-0 
45-3 
48*6 
56-5 
59-5 
62-2 
54-9 
49-5 
40-5 
39-6 
1781. 
57-9 
49-8 
43-0 
42-4 
1782. 
40-5 
35-8 
39-8 
41-8 
49-2 
58-8 
60-2 
58-0 
56-6 
46-5 
36-0 
37-6 i 
1783. 
38-5 
40-6 
38-8 
49-0 
49-4 
59-3 
66-7 
62-0 
55*7 
50-3 
43-8 
36-4 
1784. 
30-8 
33-3 
37-3 
43-1 
57-9 
57-1 
60-5 
57-5 
58-4 
45*2 
42-0 
32*4 
178.5. 
37-7 
31-8 
35-0 
47-3 
53*6 
60-3 
63*2 
58*8 
57-9 
48-2 
41*5 
36-6 
1786. 
37*5 
37-6 
35-3 
45-8 
53-4 
60-5 
60*0 
60-2 
52*4 
46-0 
38-0 
And these numbers may be considered as being very nearly the true values ; they 
are reduced to the same zero as those in Table I, of my former paper, and form a part 
of that series of values. 
Determination of the Mean Temperature of the Air at Epping for every month 
from the year 1821 to 1 840. 
Let us now proceed to compare the results of observations taken simultaneously 
towards the end of the Royal Society’s series, made as nearly as possible under the 
