
          Philada [Philadelphia] 5 mo.9th 1827

Respected Friend
Dr John Torrey

Thy letter of the 10th ulti.
was duly recd [received] & I have only delayed
answering it from the expectation of being
able to inform thee respecting the [crossed out Endro?] [added: Electro]meter
which is not yet sent. Soon after I wrote
last. Wm. [William] Mason was attacked with sever
rheumatism in his hands & legs which
disabled him from work during the
[?] winters & which has till within a
short time afflicted him. The graduation
of the ELectrometer was to be done by
him and I learn thatthe isntrument is now in his hands & will be finsihed
in a few days. I will send it when
ready to Stacy B Collins with instructions
to forward it to West Point. I have
never had any bill of the cost of
the 6 glasses which were sent to me.
The maker of the dry pile says that
he is often troubled with the columns
in the way those had been; & that he
finds that wiping them with a wet
rag to take off grease & dust & then very
carefully with a dry cloth will almost
always restore the vibration of the pendulum
        