( 788 ) 
to profecute the Inquiry, thefe Experiments may prove 
not altogether ufclefi hints, and fo ought not to be for- 
gotten. 
A Linoen Cloth being firft wet in fair Water, and then 
laid on a Concave Cylinder, as the Verge of a Seive, 
Keeler, or the like, its central Parts will defcend fo as 
to form a very regular Concave Superficies, which I ful- 
pefted to be Parabolical, well known to be the beft of 
Figures, could it be obtained for Burning Glafles,- in 
which I was not greatly deceived. 
A Thread being firft wet in common Water, and then 
fufpended with its Two Ends, or any Two Points near- 
er than their utmoft extent; fo as it might touch the 
Center of the fufpended Cloth and its Two oppofite 
Points on the the Ring was found to have the fame 
Curvature, as indeed could fcarce be doubted, fince the 
Clodi is but a number of Threads fufpended in the Po- 
flure of this fingle one. My Bufinefs then was to exa- 
mine the'Figure of a Line fufpended with its Two Ends 
nearer than their utmoft Extent, which I did in manner 
following: 
On the Side of a Wall I defcribed Parabolas of feve- 
ra! Species, whofe Axes w-ere Perpendicular and Peri- 
meter Horizontal, to which the Line being applied fbas 
it might touch the Vertex, paft very nearly through all 
the intermediate Points of the Paraboh, much nearer 
than the Portion cf a Circle which pafl through the Ex- 
tremity of the Perimeter, and Latus Return would do. 
But to make what I have faid more intelligible, fee 
Figure x, where A B is the Perimiter C D the Axis 
C the Focus and D the Vertex i,x, 3,4, 5, thefeveral 
' Points in the Parabola A FD B G, the form of the fuC 
pended Line, A H D I B, a portion of a Circle, which 
though it pafs through the Points A D B, is more remote 
from 
