[ ‘ 7 1 ] 
XIV. A Defcription of a Clepfydra or Water- 
Clock^ by the Hon . Charles Hamilton, Efq\. 
See Tab III. * Fig. i. this Machine in Perfpc&ive. 
Read April 24. & N open Canal e e> is applied with a 
1745 XJL conftant and equal Stream by the 
Siphon d\ and has at each End ff open Pipes, of 
exadly equal Bores, which deliver the Wa r er that 
runs along the Canal e , alternately into the Veffds 
g 1, g 2, in fuch a Quantity as to raife the Water 
from the Mouth of the Tantalus , s , to the Top of 
the Tantalus t y exa&ly in an Hour. The Canal e e y 
is equally poifed by the two Pipes f i, f 2, upon a 
Centre r 3 the Ends of the Canal, e y are raifed alter- 
nately, as the Cups ^ z y are depreffed, to which they 
are connected by Lines running over the Pulleys //. 
The Cups, are fixed at each End of the Balance 
mm y which moves up and down upon its Centre^. 
n 1, n 2, The Edges of two Wheels or Pulleys, 
moving different Ways ahernatcly, and fo fitted to 
the Cylinder 0 (by oblique Teeth both in the Cavity 
of the Wheel, and upon the Cylinder 5 which, when 
the Wheel n moves one Way [/. e. in the Direction 
of the Minute-Hand], meet the Teeth of the Cylin- 
der, and carry the Cylinder with it,* and, when n 
moves the contrary Way, flip over thofe of the Cy- 
linder, the Teeth no more meeting, but receding 
from each other 5 or it may be done by Catches or 
Locks, which require a longer Defcription), one or 
other of thefe Wheels, nn y continually moves 0 in 
the 
* N. B. The Letters of Reference anfwer to all the 3 Figurss fome 
being feen in one, that do not come in Sight in the others. C, M \ 
