Mr Hassler, the gentleman employed in collecting Mathematical Instruments, has called on me with his plans and drawings of an Observatory proposed to be erected at this place. He has likewise pointed out the scite which he has, after much consideration, selected as the most eligible for that purpose, and explained the reasons which determined his choice. These appear satisfactory to me and indeed conclusive. He has fixed upon square No. 634, lying about 200 yards North of the Capitol, the one on which General Washington’s house stood. The whole of this square he says will be necessary for his operations, and to prevent the erection of private buildings which might intercept the horizon, and suggests the expediency of having it secured immediately.

Mr Hassler is anxious that a decision on this point may be had as soon as is convenient. It is at his particular request I now write. If my agency can be of any service in forwarding the contemplated object it will afford me pleasure, only requesting specific instructions for the regulation of my conduct. With great respect and consideration I am Sir your Obedient Servant