354 
On determining the Height, tyc. [Nov. 
is the only real difficulty in this method. I may mention that I have found the 
refraction vary from } to ^ of the contained arc. 
Shortly after ray attention was turned to this subject, I found a paper on it in 
the Edin* Phil. Journal, Vol. 2, by Mr. Scoresby, from which it appears that he 
had not clear views of the mode of its application. He proposes to have a table 
calculated to 20000 or even 30000 feet, which being far above the highest peak 
of the Himalaya, is practically useless. With a given height he finds what ought to 
be the depression, but does "not attempt to solve the converse of the problem, 
w'hicb, however, is the only one practically useful. 
I have carried the table to every minute of the first 2 degrees, which is as high 
as it is ever likely to be used. Humboldt, from the Peak ot leneriffe, found the 
depression to be nearly 2 degrees all round. The barometrical height 12,358 feet 
corresponds to a depression of l°5b / 05". 
Table of Elevation in feet for depression nf the Sea , for each minute of the frst 2 
degrees. 
Depr. of 
Sea, 
Eleva- 
tion in 
feet. 
s-> 
«g 
1 
Q 
Depr. of 
Saa. 
Eleva- 
tion in 
feet. 
! D iff. for 
V. 
© 
ii 
^ rtj 
3oo 
Eleva- 
tion in 
feet. 
I 
£ 1 
e f 
i^epr. oil 
Sea. 
Eleva- 
tion in 
feet. 
u I 
£ 
O I 
t 
0 
0,000 
8,885 
2,650 
4,425 
6,197 
7,966 
9,738 
11,500 
13,277 
15,048 
16,828 
18,5S9 
2J,3G 
22,13 
23,90 
25,67 
25,44 
29.2 
31.0 
32,7 
34.6 
36.3 
38.0 
39.9 
41.6 
43.3 
45,2 
40.9 
48.7 
50.4 
52.8 
t 
30 
796,7 
o ' 
1.00 
318,7 
10.7 
10,9 
11,1 
11,2 
11.4 
11,6 
11,8 
12,0 
12,1 
12.3 
12.5 
12.7 
12.8 
13.0 
13.2 
13.4 
13.5 
13.7 
13,9 
14.1 
14.3 
14.4 
14.6 
14.8 
15,0 
O 9 
.30 
717,2 
16,0 
16,2 
16,4 
16,6 
10,7 
16,9 
17.1 
17.3 
17.4 
17.7 
17.8 I 
18,0 
18.1 
18.4 | 
18.5 1 
18.7 
18.8 
19.1 
19.2 1 
19,4 
19.6 
19.7 
20,0 
20,1 
20.3 
20.4 
20.7 
20.8 
21,0 
21,2 
1 
2 
3 
4 
5 
0,885 
3,501 
7,906 
14,163 
22,129 
31 
32 
33 
34 
35 
550,7 
900,4 
994,0 
1023.3 
1084.4 
54.0 
55,7 
57,6 
59,3 
01.1 
01 
02 
03 
04 
05 
329,4 
340.3 
351.4 
302,6 
374,0 
31 
32 
33 
34 
35 
733,2 
749.4 
765,8 
782.4 
799,1 
6 
7 
8 
9 
10 
31,867 
43,073 
56,650 
71,698 
88,516 
36 
37 
38 
39 
40 
1147.2 
1211,8 
1278.2 
1346,4 
1416.3 
62,8 
64.6 
66.4 
66,2 
69,9 
71.7 
73.5 
75,3 
77.0 
78.8 
80.6 
82.3 
84.1 
85.9 
87.6 
89.4 
91.2 
93,0 
94.7 
96.5 
98.3 
100,0 
101,8 
103,6 
105,4 
06 
07 
08 
09 
10 
385,6 
397.4 
409.4 
421.5 
433,8 
36 
37 
38 
39 
40 
816,0 
833,1 
850.4 
867,8 
885.5 
11 
12 
13 
14 
15 
107,10 
127,46 
149,59 
173,49 
199,16 
41 
42 
43 
44 
45 
1488,0 
1561.5 
1636.8 
1713.8 
1792.6 
11 
12 
13 
14 
15 
446,3 
459.0 
471.8 
484.8 
498.0 
41 
42 
43 
44 
45 
903.3 
921.3 
939.4 
957,8 
976,3 
10 
17 
18 
19 
20 
226,6 
25./, 8 
286,8 
319,5 
354,1 
46 
47 
48 
49 
50 
1873,2 
1955.5 
2039.6 
2125,5 
2213,1 
16 
17 
• 18 
19 
20 
511.4 
524,9 
538,6 
532.5 
560.6 
46 
47 
48 
49 
50 
995,0 
1013.8 
1032.9 
1v52,1 
1 1071,5 
21 
22 
23 
24 
25 
390.4 
428.4 
108,3 
•309,9 
553,2 
51 
52 
53 
54 
55 
2302,5 
2393.7 
2486.7 
2581,4 
2077,9 
21 
22 
23 
24 
25 
580.9 
595,3 
609.9 
624.7 
639.7 
51 
52 
53 
51 
55 
1091.1 
1110,8 
1130.8 
8150.9 
1171.2 
20 
27 
28 
29 
30 
598,4 
645.3 
694,0 
744.4 
796,7 
56 
57 
58 
59 
1.00 
2770.2 
2876.2 
2978.0 
3081,6 
3187.0 
26 
27 
28 
29 
L.3f 
654,8 
670.2 
685,7 
701.3 
717,2 
' 15,1 
15.4 
15.5 
15, G 
15,9 
56 
57 
58 
59 
2 ,0t 
1191 ,6 
1212.3 
1233.1 
1254.1 
1275.3 
Use of the table. Correct the observed depression of the sea for refraction, and 
■with this enter the table, and you have the height corresponding to the nearest 
minute. The 3d column contains the differences for one minute of depression, by 
which the height may be corrected for the odd seconds, if any. 
I have added another table 1 for every 10 seconds, as far as 30 minutes, which 
may probably be of use to those who have occasion to measure moderate eleva- 
1 J bis talile has been by accident mislaid ; should we succeed in finding it, we shall 
give its contents in another number. Ed. Gl. 
