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PEELIMINAEY NOTE ON THE DIUENAL VAEIATION OF 
LEVEL AT KIMBEELEY. 
By J. E. Sutton, M.A., Sc.D. (Cantab.), F.E.S.S.Afr., F.E.Met.S. 
(Eead July 15, 1908.) 
This paper gives the prehminary results of observations made during 
the course of three years upon the diurnal variation of the level of a 
concrete pier supporting a seismograph. The pier itself is a solid block 
of concrete 1*3 m. square, standing 0*58 m. high above ground and extend- 
ing 1-35 m. below ground, so that the total height of the pier is 1-93 m. 
Eound this pier, at a distance of 15 cm. or so, is built a brick wall, 
which serves the double purpose of supporting the floor of the seismo- 
graph-room and keeping the earth away from the sides of the pier. 
Therefore the indications of the seismograph may be taken as applying 
to the stratum 1*35 m. below the surface of the ground. The seismograph 
is of the horizontal pendulum form, the boom carrying a weight of nearly 
6 kilograms. There is an adjusting screw for sensibility, and a graduated 
micrometer screw for the purpose of measuring the tilt. The indications 
of the pendulum are received upon a sheet of smoked paper travelling at 
the rate of 15 cm. an hour. The pendulum part of the apparatus (which 
was made to my design, with some modification, by the Cambridge Instru- 
ment Company) has served the purpose I had in view very well. There 
is room for a good deal of improvement, however, in the clockwork and 
drum. The apparatus is housed in a wooden hut of weather-boards, the 
walls being double and lined with cinders. There is not a window to the 
hut, a space being left under the eaves for ventilation. 
The pendulum is adjusted in the meridian to a mean period of 18 
seconds, which, however, varies somewhat during the course of the year. 
A tilt of 1 second of arc corresponds to an average deviation of the 
extremity of the boom of almost exactly 2 mm. 
In Table 1, at the end, will be found the results in monthly averages. 
