f ) 
i758ooRevolut. tranflateit ^of a Circle in I 705 '. 43 19. 
II ^ « Q/ ^ Jl <"l -JHU 
13i8,099”j or O.lO 2«5 2,6 1 2, 5^5^ • 
117200 Revolut.tranflate it;|of a Circle in ii^ 6 . 9 ‘> 79 > 
4878,751", or 0.18' $ 6 " 57"' 28"" 36'"". 
If the Terrella’s Circumference is more than 6 
Inches, the inagnetical Poles thereof may be placed fo 
oblique to the Axis of the Cylinder, as that in turn- 
ing round they may each of them defcribe a lelTer 
Circle (or as it may be called a Parallel of Latitude) 
juft 6 Inches in Circumference, and that will caufeno 
Alteration in the Swiftnefs. of the Motion of the Ma- 
chine, which is to be moved as follows, The Per- 
fon that works it muft keep his Eye on a Pendulum 
ofcillating Seconds, and turn the Crank (or Turner) 
once round at each Ofcillation, fo (hall the Number of 
the Terrella’s Revolutions, and Celerity of the Motion 
of its Poles be as is above-mentioned. 
But if the Terrella is larger than 6 Inches in Cir- 
cumference, and its Polarity tranfverfe to the Axis of 
its Rotation, the Pendulum may be lengthened in Pro- 
portion of the Squares of their Circumferences, and 
the Crank muft then make one Turn at each Ofcilla- 
tion of the Pendulum fo lengthened •, and by that 
Means it will move- with the fame Celerity which 
was above propofed ^ but then the 703200 Revolutions 
will not be finifhed in lefs Time than 6821 Seconds 
(or rather Ofcillations) made by the lengthened Pen- 
dulum. 
If by the keeping a Terrella in Motion in fuch a 
Pofture, and with fuch Celerity as is aforefaid, the 
magnetical Poles thereof, in refpeft of the Terrella, 
remain immoveable, I think this is a plain Demon- 
ftration that the central Magnet is loofe from the 
Earth, 
