108 Newellian Sphere. 
ses nearly, are determined. Near the antarctic extremity of 
the earth’s axis, and attached to the projecting centre of one 
of the wheels which support the earth in the annual circle, is 
a stationary plate, or dial, having its 12 o’clock point con- 
stantly towards the sun. By referring the points on this dial 
to the earth, the places where the sun is rising or setting, and 
the beginning and end of twilight, is shown for the given 
time. Near the north extremity of the ecliptic, or main axis, 
is a weekly wheel, with an index, showing the several days of 
the week. 
The wheel work of the machine is made of brass, with 
the exception of some of the pivots and small pinions, which, 
on account of their greater action, are made of steel. The 
power for communicating motion to the whole, is applied to 
a diurnal wheel, at the arctic extremity, either by hand, 
through the intervention of a crank, or by a time-piece, geat- 
ed to the diurnal wheel. If it be necessary at any time te 
hasten the movements of the machinery, for illustration, the 
time-piece may be easily disengaged, by withdrawing the di- 
urnal wheel from its action, the motion of the time-piece not 
being ehecked, By observing the time when thus disen- 
gaged, and setting the machine forward a space equal to the 
elapsed time, it may be again thrown into gear, and the 
whole move on as though there had been no interruption. 
It may seem a matter of impossibility, that a time- piece, of 
ordinary dimensions, burthened with the resistance which 
such a mass of machinery would be supposed to present, 
should yet be enabled to move the whole, and itself preserve 
an uniformity in its motion. This doubt, however, will in @ 
great measure be removed, when we eonsider the immense 
mechanical advantage under which it operates. The diurnal 
wheel, with which it immediately communicates, has a velo- 
city, in comparison with the principal annual cirele, of 3654 
to 1, and consequently possesses a mechanical advantage in 
that ratio. This adyantage is still greater on the combina 
tion of wheels carrying the superior planets, in as much as 
their motion is slower; and, in fact, the comparative e- 
rate motion of the different parts, gives a great ratio in fa- 
vour of the diurnal driver, It raust be understood, likewise; 
made to assume by the motion of the machine. From this 
