49 
There are evidently great discrepancies between the two 
series of values, which it is quite out of my power to 
explain, but reference to the monthly means for Old Trafford 
show that the probable variations during the period 1849- 
1868, must have been much greater for some of the months 
than those given from Dalton's earlier period, especially in 
the month of February ; in 15 years of the Old Trafford 
observations the variation of the mean temperature of 
February, from the mean of the period, exceeded 1 Q, 8 the 
amount from Dalton’s observations, very considerably. The 
same may be said of other months, but not to the same 
extent. 
Table I. 
& 
Mean Monthly Temperature at Old Trafford, Manchester, 
1861-1868. 
Year. 
Jan. 
Feb. 
Mar. 
Apr. 
May. 
June. 
July. 
Aug. 
Sep. 
Oct, 
Xov. 
Dec. 
o 
o 
o 
o 
o 
o 
O 
o 
O 
O 
o 
o 
1861 
35-0 
40-0 
43-0 
44 ’4 
49-3 
56-6 
59-3 
— 
55-2 
52-8 
38-0 
39-5 
1862 
38-1 
41-0 
42-0 
41'2 
47-8 
48-0 
56-7 
58-0 
54-7 
49-1 
36-8 
43-0 
1863 
42-4 
41-8 
43-8 
47 6 
50-9 
57-0 
51-5 
52-4 
47-7 
48-9 
45-0 
42-9 
1864 
35-6 
35-2 
38-8 
48-3 
5A2 
56'0 
58'3 
55-6 
54-7 
49-0 
43-0 
48-5 
1865 
35-0 
35-5 
365 
50-5 
53-9 
59-8 
61-6 
58-1 
60-9 
49-0 
43 1 
41-9 
1866 
39'7 
34-7 
35-5 
.47-3 
48-9 
59'6 
57-0 
57-5 
53-8 
490 
43-7 
416 
3 867 
33-2 
39-9 
37-2 
48-7 
53-3 
56-6 
5.8-4 
60-5 
56-2 
47-7 
38-7 
38-4 
1868 
38-9 
42-8 
43-8 
462 
553 
57-5 
63-3 
61-3 
57-6 
46-6 
40-8 
44-1 
Means, 
1861tol868 
37-2 
38-9 
40-1 
46-8 
51-7 
56-4 
58-3 
57-6 
55-1 
49.0 
41-1 
40-4 
- 
August, 1862. Determined by reduction from the Ob- 
servations made at Eccles, by Thomas Mackereth, Esq., 
F.R.A.S. I may remark here that our observations are 
nearly identical, or where different seem to be so almost by 
a constant difference. 
January, 1863. From Mr. Mackereth’s Observations. 
April, May, June, July, August, September, 1868, taken 
from Mr. Mackereth’s Observations. 
