140 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1919. 
most convenient for unpacking and storage and in the preparatory 
work. We laid down a meridian line, after which brick piers were 
constructed for the ccelostats and for the steel tube of the astro- 
graphic telescope. Whilst this was in progress the huts were being 
erected. 
The pier of the small celostat was constructed so as to leave a 
clear space in the middle of one end for the fall of the weight, 
which was thus below the driving barrel of the clock. By continuing 
the hole below the foundations of the pier, space was provided for 
a fall of the weight permitting a run of 25 minutes. In the case 
of the 16-inch celostat, the clock was mounted on the top of a long 
wooden trunk, nearly 4 feet in length, which was placed on end, 
and sunk in the earth to a depth of about 2 feet. The weight 
descended inside the trunk directly from the driving barrel, and had 
space for a continuous run of over half an hour. 
The 16-inch ccelostat had free adjustment for all latitudes; but 
the 8-inch one, constructed for European latitudes, was mounted 
on a wooden base, inclined at an angle of about 40°, constructed 
before leaving Greenwich. The clock had to be separated from the 
colostat, mounted on a wooden base and reversed, to adjust to the 
Southern Hemisphere. It performed very satisfactorily, and no 
elongation of the star images is shown with 28 seconds’ exposure. 
To provide for the changing declination of the sun the piers of 
the astrographic telescope were made with grooves in the top, in 
which the wooden V-supports of the tube could slide, thus allowing 
for the change of azimuth. 
The tube of the astrographic telescope was circular in section, and 
could rest in any position in the V’s; for convenience it was adjusted 
so that the directions of right ascension and declination were paral- 
lel to the sides of the plate; this involved a tilt of the plate holders 
of about 4 degrees to the horizontal. 
The 4-inch lens was taken as an auxiliary; we used the square 
wooden tube, 19 feet in length, originally used by Father Cortie at 
Hernosand in 1914, together with the 10 by 8 inch plate carriers. 
Study of the star diagram showed that seven stars could be. photo- 
graphed by turning the plate through 45°. The tube was therefore 
placed on its angle, large wooden V-supports being prepared to fit 
the tube; these rested on strong wooden trestles. 
The focusing was at first done visually on Arcturus, using an 
eyepiece fitted with a cobalt glass, after the plate supports and 
object glass had been adjusted for perpendicularity to the axis. 
A series of exposures was then made, the focus being varied slightly 
so as to cover a sufficient range. Examination of these photographs 
showed at once that there was serious astigmatism due to the figure 
_—- so. 
