p.1

Princeton N. J.

May 11th 1865.

Dear Sir,

I am very much indebted
to you for your kind communication
received already nearly a month ago
& containing the levels of the [Parius?]
RR. Such documents are for me
peculiarly valuable.

I have to beg your pardon
for not having immediately returned
such information as I could furnish
you on the height of land between
the lakes & the [Thunder?]bay; but
absence from town & urgent duties
at College cut this closing period of
my lectures, paralyzed my Scientific
movement.