39^ 
Dr. R. Hey’s Propositions, &c. 
As to the cases of AO being 'AF and greater, and that of 
mean points within the circle LOR with the centre A ; it seems 
unnecessary to add to what was said in concluding that part, 
of this proposition, in which the mean points were supposed 
to be in a right line. 
Since the axes of the hyperbola are given in length and 
position, it could be described. And its intersections with the 
diameters ST would give all the mean points. Whether this 
would aid the perspective operations so much as to compen- 
sate for the labour of constructing the curve, I leave to others 
to examine. 
RICHARD HEY. 
March 1814. Hertingfordbury, near Hertford, 
