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ceftlve, will exhibit a rotatory regreJTive Motion, 
quite contrary to what the Tube had when fupported 
near its Extremities: And when a Tingle Tube lies 
inclining oppofite to the Fire, either to the Right- 
hand or the Left, out of a Piane perpendicular to the 
Surface of the Fire, Gravity will not permit the 
curved Part to reft, but pull it down till it co incides 
with a Plane perpendicular to the Horizon ; and, con- 
fequently, as new Curves are generated, new Motions 
will be fo too; that is, the Tube will be made to 
move about its Axis ; but with this Difference, when 
the Tube inclines to the Right hand, the Motion about 
the Axis will be from Eaft to Weft; when to the 
Left-hand, from Weft to Eaft. The Juftnefs of this 
Reafoning is made manifeft with a very little Trou- 
ble; only bending a Wire, and fupporting it firft near 
its Extremities, then near its Centre on each Side, 
afterwards inclining it to the Right, and then to the 
Left ; the Bending in every Cafe reprefenting the 
curved Part of the Tube next the Fire. And that 
this Solution is the true one, Teems farther probable 
from hence, that when four Supporters were made 
ufe of, one at each Extremity, and two near the 
Middle, there was no Motion at all either backward 
and forward : Nor is it of any Service to objed here, 
that the Increafe of Contact hinders the Motion j 
becaufc, upon the Plane of Glafs, mentioned in my 
former Paper, fo large as to have a much greater 
Contad with the Tube, both a rotatory and regref 
five Motion was manifeft. I am, worthy Sir, with 
a high Regard, 
Tour moft obedient humble Servant, 
London, April 1745 . 
Granv. Wheler. 
IL 
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