228 Translation from the Astronomical Jour. of Hamburgh. 
at their ends the screw work for the stands by which the in- 
strument rests upon three vertical cones of brass, fastened 
to the wooden stand of the instrument ; between this and 
the six horizontal conical arms there is room for the verifi- 
meter screw. The illumination is made through the axis of 
the telescope, the one side of which is perforated, the other 
has an altitude circle of six inches diameter. The axis is 
about twelve inches long, which is more than the interval 
between the columns. Its supports are therefore set upon 
pieces of brass, elevated above the columns, and extending 
outwards; they have the same kind of vertical adjustment as 
the large transit described above. 
In relation to the observations with this instrument, Mr. H. 
roperly remarks: that the eccentricity is equally corrected 
y means of three equidistant readings, as by two, four, or 
so on; he also shews, that when the vertical axis is not per- 
pendicular to the plane of the horizontal circle the errors 
of the angle will be corrected if the position of the instru- 
ment’s place is alternately changed to the three truncated 
cones of the stand, so as to give the three regularly succeed- 
ing positions of a fullrevolution. These three observations, 
each made in the two diametrically opposite positions of the 
telescope, and by a half revolution of the instrument, give 
a mean which is free from eccentricity, from any error arising 
from the inclination of the circle towards the axis, or from an 
inequality in the supports of the axis, the readings being be- 
