p.2

[Left page]
plane which is Lake Erie, which I take at
568 ft above sea.

In order, however, to assist at your
arriving at appropriate [illegible] I give
you altitudes of the [nearest?] points on the
intersecting Railroads, which with the distances
may help. Unfortunately, I have
never been able to get a list of the
altitudes on the St Louis, Alton and
Chicago RRd - and fear that, as in
many similar cases my desiderata
are precisely those of correspondent's:
One of the principal railroad [illegible]
having failed to return replies, though
carefully and [illegible] & repeated.

Your queries, however, induce me to make
a fuller attempt upon the last named
railroad, as well as other - the
continuation of the [illegible] & Peoria
being one of them.

Notwithstanding this mishap of delay,
please address me for any further enquiries
which I shall [illegible] attend to.

[Right page]
The heights are above near level of sea.
[pen sketches]

Note. The Illinois Central levels are reduced to sea level
from the [Engineers'?] returns, which are referred to Low water
in Ohio River at [illegible], which I assume at 276 feet
above sea level, from the Mobile & Ohio RRd [Engineers'?] levels.

Yours respectfully
Walter L Nicholson
Topographer to P.O. Dept

I. A. Lapham Esq
Milwaukee
Wis.