we know from pre1849 maps that the depa arc was originally tangent to
demd at modern demdpa
or at least it appears to have been so
&
we understand that the wedge was created in 1849 as a prolongation of
the demd arc
which had a smaller radius than the depa arc as well as a different
center
&
we know that the western part of the depa arc was shaved back at that
time
in order to feather these 2 or 3 slightly different arcs together
into a single continuous curve from the delaware river to the m&d
tangent point
etc

but how was it possible that the original 1701 depa arc & the
original 1764 m&d north line from the demd tangent point could both
have struck the m&d west line at precisely the same point
modern demdpa

or at least how can they appear to have done so

for it seems to me one or the other of these 2 chance intersections
would have produced & become the definitive demdpa
while the other would have had to miss the mark

the intersections were independently conceived & generated
one being supposedly 12 miles from the horse dike at new castle
& the other 15 miles south of the southernmost point of philly as
well as due north of the more famous tangent point

neither position was derivative of the other
yet both apparently agree

so i am thinking
m&d
or at least someone prior to graham in 1849
might already have done some fudging of the westernmost end of the
depa arc here just to make everything line up

of course in 1849
whatever slight previous fudging may also have been done was
completely obliterated by the much greater fudging produced by graham

so this is a question only for ghost pointing
& perhaps only to be answered in some dusty archive if at all

but it titillates my sense of & desire for precision