x INTRODUCTION. 
opening for a foundation to the Observatory would shew, to be covered with masses 
of rolled pebbles, and boulders of ereywacke and trap. 
4. The Observatory is rectangular in its plan, 40 by 20 feet internally. It is 
formed of wood; copper nails were used; and iron carefully excluded from every 
part of the structure. 
The pillars for the Magnetomers and Telescopes are of stone, from 22 inches 
to 19 inches in diameter, and placed upon excellent stone foundations, completely 
disconnected with the floor, or any part of the building. There are two windows 
to the south, with the door between ; and three to the north, which open like fold- 
ing doors. 
5. By a reference to the plan and elevation, the following details will be un- 
derstood :— 
The dimensions of the principal apartment are, 40 feet long, 12 feet broad, 
and 12 fect high. The two ante-rooms are each 15 feet by 7. 
The instruments, &c., are indicated in the plan as follows :— 
D, The Declinometer. 
t, Its Reading Telescope. 
A, The Azimuth Circle and Transit. 
H, The Bifilar or Horizontal Force Magnetometer. 
’, Its Reading Telescope. 
P, A Pillar for a Collimator (not used). 
V, The Balance or Vertical Force Magnetometer. 
I, The Inclinometer. 
B, The Standard Barometer. 
W, Adie’s Anemometer. 
W’, The Wind Vane Dial-Plate. 
T, The Thermometer Case after January 22. 1842. 
T’, The Thermometer Case before January 22. 1842. 
C, The Mean Time Clock. 
S, The Copper Stove after Jan. 11. (?) 1842. 
S’, The Copper Stove before Jan. 11 (?) 1842. 
ns, The Astronomical Meridian. 
D t, The Magnetic Meridian. 
The two Vanes to the right in the elevation are those for the direction and 
force of wind ; the other two were added after 1842. 
§ 2. PERsoNAL EsTABLISHMENT, &c. 
6. Mr RussELL was appointed by Sir Tuomas BrisBane, in the spring of 
