DETEEMINATION OF DEFLECTION OF LIGHT BY THE SUN’S GRAVITATIONAL FIELD. 297 
Here we were met by Mr. John Nicolau, who had been instructed to assist us with 
our baggage through to Sobral. We proceeded from Camocim to Sobral by train 
on April 30, our baggage following the next day. 
We were met at Sobral station by representatives of both the Civil and Ecclesiastical 
Authorities, headed respectively by Dr. Jacome d’Oliveira, the Prefect, and Mgr. 
Ferreira, and conducted to the house which had been placed at our disposal by the 
Idndness of its owner. Col. Vicente Saboya, the Deputy for Sobral. We were joined 
there nine days later by the Washington (Carnegie) Eclipse Commission, consisting 
of Messrs. Daniel Wise and Andrew Thomson. 
We are greatly indebted to Dr. Leocadio Araujo, of the State Ministry of Agri¬ 
culture, who had been deputed to interpret for us and to assist us in our preparations. 
His services were invaluable, and contributed greatly to our success, as also to our 
well-being during our stay. 
10. A convenient site for the eclipse station offered itself just in front of the house ; 
this was the race-course of the Jockey Club, and was provided Avith a covered grand 
stand, which we found most convenient for unpacking and storage and in the pre¬ 
paratory work. We laid down a meridian line, after which brick piers were constructed 
for the coelostats and for the steel tube of the astrographic telescope. Whilst this was 
in progress the huts were being erected. 
The pier of the small coelostat was constructed so as to leave a clear space in the 
middle of one end for the fall of the weight, wliich 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 coelostat, 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 coelostat had free adjustment for all latitudes; but the 8-inch one, 
constructed for European latitudes, was mounted on a wooden base, inchned at an angle 
of about 40 degrees, constructed before leaving Greenwich. The clock had to be 
separated from the coelostat, 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 Vs ; for convenience it was adjusted so that the directions of R.A. and 
declination were parallel to the sides of the plate ; tliis 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 
