342 An Astronomical Machine, the Tellurium. 
round the sun. The wheel A contains 293 teeth, and the pin- 
ion which belongs to the wheel B contains 8 leaves, consequently 
B must make 363 turns during one turn of the wheel A. The 
wheel B contains 80 teeth, and the pinion C contains 8 leaves; 
consequently C must make ten turns during one turn of the wheel 
B, and ten times 36% or 3664 turns during one revolution of the 
wheel A, that is, in one year. he little wheel upon the upper 
end of the axis of the pinion C contains the same number of 
teeth as the pinion 0, therefore the earth must turn on its axis in 
the same time as the pinion C; it must make 3664 diurnal rota- 
tions ina year, each rotation being performed in a sidereal day or 
23h. 56m. 4s. The wheel E contains 167 teeth, and the wheel 
O contains 25 teeth. Consequently O, and also the wheel P, 
must make 612 turns during one turn of E. The wheel P con- 
tains 72 teeth, and the wheel D contains 36 teeth, consequently 
D must make two turns during one turn of P, and twice 612 or 
13,2; turns during one turn of the wheel E, or in one year. As 
the circular. brass plate c is fixed upon the socket of the wheel 
D, this plate must turn with the wheel and carry the moon V 
13.°. times round the earth U ina year, which is equal to the 
number of the moon’s sidereal revolutions in this time. The 
teeth of the wheel G act upon the teeth of the wheel F. The 
wheel G contains 20 teeth, and the wheel F contains 372 teeth, 
consequently G must make 18,°, turns, while F turns once round, 
As the wheel G makes but one turn on its axis ina year, the 
wheel F must require 18,°, years to perform a revolution. The 
oblique plate d, to which the moon’s orbit is parallel, being fixed 
upon the socket of the wheel F, the plate must turn with this 
wheel and carry the moon’s nodes round contrary to the order of 
the signs, so as to perform a sidereal revolution in 18,5 years. 
The teeth of the wheel I act upon the teeth of the wheel r, 
which, as before stated, transmits motion to the wheel H. The 
wheel I contains 20 teeth, and the wheel H contains 177 teeth, 
consequently I must make 817 turns in order to turn F* round 
once. As the wheel I makes only one turn in a year, the wheel 
H must be 837 years in performing a revolution. ‘The index ¢, 
which is fixed upon the socket of H, must turn with this wheel 
and also perform a revolution in 812 years, which is the time in 
which the moon’s apogee performs a sidereal revolution ; there- 
fore, this index will show the proper motion of the apogee. 
See 
