4 90 
Mr. Ivory on the astronomical refractions. 
Stars. 
No. 
of 
Obs. 
Mean 
Apparent 
Altitude. 
Mean 
Observed 
Refractions. 
Mean 
Bar. 
Mean 
In. 
Ther. 
Out. 
Corrections 
of French 
Table. 
Corrections 
of New 
Table. 
1 1 Lacertae. 
O 
, 
II 
1 
II 
0 
O 
II 
l6 
»s 
4 
10.5 
IO 
10.5 
29.91 
47-5 
38-3 
— 5-3 
5.1 
x Androm. 
12 
85 
4 
37-8 
10 
3-7 
29.72 
5 1 
43-5 
2.2 
— 
1 .1 
| Cygni. 
15 
10 
5»-3 
IO 
23 -3 
29.92 
46.6 
38-5 
—4.2 
— 
3-8 
f 4 Ursae Maj. 
IO 
53 
57-3 
1 1 
55.8 
29.83 
41 
32.8 
— 3-7 
— 
3-5 
» Androm. 
8 
86 
6 
22.2 
12 
104 
29-73 
49-4 
39-8 
— 3-3 
— 
2.6 
y Androm. 
10 
86 
53 
9.1 
*3 
46.7 
29.75 
60.3 
54-3 
—7.0 
— 
1.2 
o Androm. 
12 
86 
58 
29.9 
14 
41.5 
29-93 
48.6 
38-9 
—2.9 
— 
27 
@ Bootis. 
5 
87 
8 
27.5 
15 
21.8 
29.70 
38.4 
28.7 
—9 7 
— 
14.2 
»> Aurigae. 
9 
8? 
18 
57.8 
*5 
14.2 
29.85 
60.2 
56 3 
—2.9 
+ 
5.1 
£ Aurigae. 
13 
87 
29 
7.6 
15 
44.9 
29.78 
62.4 
566 
—6.4 
+ 
2.3 
(3 Persei. 
*7 
87 
59 
51.9 
18 
7 1 
29.89 
59-7 
52.5 
—6.6 
+ 
°-4 
7 Cygni. 
25 
88 
29 
50.5 
21 
3 7 - 6 
30.05 
46.5 
38.1 
— 0.9 
7.2 
■ Persei. 
16 
88 
4 1 
17.4 
22 
23.0 
30.01 
58.3 
49-3 
+ 6.9 
+ 
10.8 
If we reject the observations of j 3 Bootis and e Persei, the 
errors of the French Table are all negative ; and, in the New 
Table, the negative amount to more than triple the positive 
errors. Two different reasons may be assigned for the pre- 
ponderance of the negative errors : it may be alledged that 
the refractions in the Tables are too great ; or it may be said 
that, by using the exterior thermometer, the calculated re- 
fractions are increased more than in proportion to the real 
temperature of the air. The latter of these reasons is quite 
sufficient to account for the discordance ; and it will receive 
additional force, if we attend to the great differences between 
the exterior and interior thermometers. In this case we 
cannot, therefore, draw any conclusion with the same confi- 
dence as in the preceding observations of Dr. Brinkley ; but 
we may safely affirm, that the errors of the Table are not 
greater than the uncertainty of estimating the temperature of 
the air by the exterior thermometer. 
