118 
The points on which I relied when venturing to bring 
the problem under the notice of your Society were, its 
practical importance; the simplicity of my construction; 
and the fact that the same solution had not before been 
published, or if it had, was very little known. On all these 
points Mr. Raw’son has confirmed the correctness of my 
opinion. 
The solutions referred to by Mr. Rawson may, from his 
point of view, be conveniently arranged into three classes : 
(1) those which are quite different from mine ; (2) one which 
might have been the same had it been done in different 
way from what it is ; and (8) one by Waud which is the 
same with one exception. I have not yet been able to find 
the book containing this last solution, and cannot therefore 
say how nearly identical the two solutions may be ; but as 
the generating circle is the most important part of my con- 
struction, seeing it determines both the directions and 
lengths of the axes, and as Mr. Rawson says the circle is 
not introduced in Waud’s solution, I cannot but think the 
exception must be an important one. 
It is scarcely necessary to observe that I laid no claim to 
having discovered a new geometrical principle, but I did 
think that by looking at the problem from a different point 
of view from most of the writers on Geometrical Conics I 
had succeeded in obtaining a solution which was at once 
simple to execute and easy to remember, and I submit the 
proper test by which to judge it is to take the compasses 
and work the problem by the several known methods, when 
the simplicity of my method as well as its points of difier- 
ence from the others will become apparent. 
“ On Discoveries in a Cave at Thayingen, near Schaff- 
hausen,” by Arthur Wm. Waters, F.G.S. 
Last meeting our attention was drawn by Professor Boyd 
Dawkins’ interesting paper to the large number of settle- 
