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XX. An improved method of dividing Astronomical Circles and 
other Instruments, By Capt. Henry Kater. Communicated 
by Thomas Young, M. D. For. Sec. R. S. 
Read May 5, 1814. 
The art of dividing astronomical circles and other instru- 
ments for taking angles, has ever been thought highly 
important to the improvement of astronomy and geography, 
and has consequently, at different periods, formed a subject of 
much attention and inquiry. The method of dividing, which 
until very lately was in general use, was that practised so 
successfully by the late Mr. Bird ; but the laborious and 
delicate operation by the scale and beam compasses, has 
' recently been superseded by the invention of Mr. Troughton, 
of the excellency of which the mural circle at the Royal 
Observatory at Greenwich affords a noble proof. But this 
method, though decidedly superior to Mr. Bird's, seems yet 
to leave somewhat more to be done with respect to simplicity 
and facility of execution ; and it is with the hope of having in 
some measure attained these desirable objects, that I am 
induced to lay before the Royal Society a mode of dividing, 
which, I am led to believe, will not be found inferior in accuracy 
to any that has hitherto been proposed. 
In the essential principle on which this method is founded, 
I find that I have been anticipated by the Due de Chaulnes ; 
but some parts of the apparatus which he has described are so 
