
          U.S. Patent Office 13 Sept 1853


 My Dear Sir


 I learned a day or two ago [inserted: from Mr. Schaeffer] that you were
 engaged to analyze the waters of the Potomac in regard to the
 supply of our City with water, and that you would be glad
 to have a quantity of the water evaporated in my [crossed out: furnaces]
 Sand bath, but that you did not like to give me
 the trouble to do it. I take this opportunity to offer you
 the use of my Laboratory in any way you choose for your
 purposes, or what may perhaps be preferable to collect the
 amount of water you may designate [inserted: from the river above Geo-town] and evaporate it
 to such a point as you may desire and send it to you
 by express or in any other way  you may suggest.
 It will give me great pleasure to serve you in this matter,
 and I hope & trust you will not again hesitate to allow
 me the pleasure of requiting some of the obligations of 
 my former days.


 Since I have had the pleasure of seeing you I have
 had the good fortune to find what I believe to be the
 real Bartram oak within a couple of miles of the 
 Capitol & on the borders of the forest. It is a tree some
        