44 
MR. BARLOW’S ACCOUNT OF THE CONSTRUCTION OF 
of accuracy ; and it will not of course be understood that I am now speaking 
of extreme astronomical accuracy. 
I found, however, the action so complete, that I determined to try how far it 
could be useful in this way. The lower curb was therefore carefully divided 
by hand into degrees and quarters, the meridian obtained by the best means 
in my power, an index fixed to the bottom of the frame and adjusted to the 
zero of the circle. A graduated circle, not seen in the plate, was then attached 
to the bearing frame with a suspended plummet, the telescope put upon a 
meridian star whose altitude was known, and the arc adjusted accordingly. 
With these apparently rough means, and another for converting right ascen- 
sion and declination into azimuth and altitude ; and with the help of an ex- 
cellent pocket chronometer by Messrs. Parkinson and Frodsham, my son, 
who has acquired great dexterity in the use of the instrument, can at any 
time select the right ascension and declination of the star from the catalogue, 
convert these into azimuth and altitude, direct the instrument towards the 
object, and be seated quite at his ease observing, in three minutes. 
In a bright night, — and for observing a known star this is of course unneces- 
sary ; but for less conspicuous stars, which are scarcely distinguishable except 
by their catalogue positions, as also for finding any star before daylight is quite 
gone, or a planet in the day-time, these means, although far short of those 
afforded by an accurate equatorial, are very serviceable. 
It should be observed that the stand was originally designed to work from 
the horizon to the zenith, which it is capable of doing ; but I have limited its 
present action to an altitude of 65°, this being the greatest height I can obtain 
without cutting the upper curb of my observatory roof, which I am rather un- 
willing to do, for obtaining what is at best, with such an instrument, a very in- 
convenient position for observation. 
Description of the Observatory. 
It has been already stated that this room is circular, having a clear diameter 
of 1 6 feet. It is constructed as follows : A foundation wall 4 feet deep of 1 4-inch 
brickwork is first laid, and on this is imbedded a circular wooden curb in two 
thicknesses, each 2 inches deep and 4 broad, properly united with bolts, screws, 
and keys. Another exactly similar curb, united in the same way, forms the 
