50 Dr Brinkley’s Catalogue of 46 principal Stars , 
Baron Von Buch divides volcanic islands into three classes, 
which he characterises in the following manner : 
1. Basaltic Islands. Composed of strata of basaltic rocks, in 
which there is general!} 1 - a crater of elevation (Erhebungs crater.) 
% Volcanoes. Isolated ; very elevated peaks, and domes of 
trachyte, and generally with a great crater on the summit. 
3. Erupted Islands . These have been formed by single 
eruptions, and scarcely ever occur without basaltic islands. 
The Island of Ascension is, by Von Buch, referred to the 
third division ; but it now appears, from the facts stated above, 
that this island belongs not to the third alone, but rather con- 
joins in it the characters of the second and third classes *. 
* Professor Jameson had the goodness to examine the different rocks enume- 
rated above. 
Art. VII. — A Catalogue , in Right Ascension , of 46 principal 
Stars , deduced from Observations made at the Observatory of 
Trinity College , Dublin , in the years 1823 and 1824. By 
the Rev. Dr Brinkley. Communicated by the Author. 
Stars. 
M 
1825. 
Ann. Var. 
1824. 
Sec. Var. 
y Pegasi, 
a Cassiopeae, 
h 
0 4 13,91 
0 30 37,85 
+ 3,077 
+ 0,010 
3,333 
0,051 
Polaris, 
0 58 17,10 
15,000 
a Arietis, 
1 57 19,52 
3,354 
0,020 
a Ceti, 
2 53 8,26 
3,120 
0,010 
a Persei, 
Aldebaran, 
3 11 52,30 
4,221 
3,427 
0,049 
4 25 53,12 
0,011 
Capella, 
5 3 46,31 
4,411 
2,877 
0,019 
Rigel, 
5 6 7,75 
0,004 
/3 Tauri, 
5 15 13,97 
3,781 
0,009 
a. Orionis, 
5 45 41,83 
3,243 
-1- 0,003 
Sirius, 
6 37 25,96 
7 23 25,07 
2,643 
0,000 
Castor, 
3,847 
— 0,012 
Procyon, 
7 30 8,08 
3,146 
0,004 
Pollux, 
7 34 35,56 
3,684 
0,012 
a Hydrae, 
9 18 59,15 
2,948 
0,001 
liegulus, 
9 59 2,41 
3,204 
0,010 
a Ursae majr. 
10 52 50,65 
11 40 7,47 
3,801 
0,086 
/2 Leonis, 
3,065 
0,008 
y Ursae major. 
11 44 34,79 
3,208 
2,670 
0,046 
£ 
12 46 17,78 
— 0,029 
I Spica Yirg. 
13 15 58,93 
3,143 
+ 0,011 
| v Ursae major. 
13 40 37,95 
2,377 
— 0,011 
