Your Polygraph was nearly finished before I received your favor of the 21st. Instant, and your improvement to command the pull of the spiral Spring shall be made to it.

The Machine appears on a short tryal of it, to perform with great accuracy & considerable freedom. The joints are made to fit close without being stiff, and I have thought it best, not to use a single drop of oil in puting it togather, under the Idea, that oil may make the moovements easy at first, yet when it becomes thickened by the friction of the metals, that, it is then a disadvantage. The question is, whether smooth steel & brass well fitted togather, by use, shall acquire so high a polish as not to require the aid of oil? The experiment is deserving of tryal. Oil may be put at any time to the points with a feather, & if limpid, will flow through every part, without the machinery being taken to pieces.

I am anxious you should receive this Polyraph as early as possible, and therefore I will endeavor to get it sent by the mail Stage. taking care to put it up in such a manner as it shall not be injured by the jolting of the Cariage.

I now write with it, will make further tryal tomorrow, and then complete all the appendages. I shall try to find some Passenger who will be so obliging as to take charge of it & will write again to make further remarks on the construction of it.

I wish Philada. had greater charms, that we might have the pleasure of seeing you; all the members of the Philosophical Society would rejoice,

but none more than your friend