104 Newellian Sphere. 
the work, under the immediate superintendence of two genile» 
men attached to the Military Academy. 
n a more particular examination of the machine, it was 
ascertained, that the motions produced were not given with 
the degree of accuracy required to place it on an equal foot- 
ing with others, heretofore designed for the same purpose.— 
The estimations of the work, likewise, were, in certain cases, 
made upon erroneous principles. As an instance of the first, 
only 365 days were designed to be given to the year, which 
is not so near an approximation to the true number as is given 
by most other machines: and, as an instance of the second, 
in describing the rotary motion of the earth, the effect of a 
compound motion, arising from its revolution around the sun, 
was not considered in the calculation. From these reasons it 
was found necessary to make an entire change in the caleu- 
lation of the wheel work. In the communications of motions, 
likewise, a sufficiently strict adherence to mechanical princi- 
$ was not maintained. The application of the driving to 
the production of a steady and equable motion, not affording 
to be impelled by a time moving power. 
In order to do away these imperfections, it was necessary to 
new model the whole, and a complete change in the mechani- 
cal arrangement of the different parts has been the conse- 
quence. : 
With the alterations above mentioned, important additions 
have been made, and the design so extended as to embrace 
many of the most interesting phenomena of the solar system, 
which are not represented in the original contrivance. Amon, 
the principal of these phenomena, are those which would re- 
sult from the addition of the superior planets; the inclina- 
tions of their orbits to the ecliptic, particularly that of the 
moon, with the change of its nodes; the correct relative 
distances, from the sun, of the earth and inferior planets; 
and the firmament, with the principal stars in its several con- 
stellations. The whole, it is believed, having been accom- 
the science of astronomy, more perfect, and consequently 
more valuable, than any that has heretofore been devised for 
- the same purpose. A description of the machine, in its pre- 
sent improved state, is given as follows : . 
