I recieved last night your favor of the 19th. and am sorry you have paid so much respect to my dimensions as to puzzle yourself with them, and still more to alter the writing machinery. they were meant to be entirely subject to your correction, & they are still so. I made1 the drawing from memory, & have seen since I returned here and have had a polygraph under my eye that I had not left room enough for the horizontal rhombuses to move on. whether they will perform their functions equally well if made only rhomboidal you will be able to judge, and to yourself I leave it entirely. as soon as the desk is ready I shall be glad to recieve it, because, after trial, I shall wish a second and perhaps a third to be sent to Monticello in time to meet me there by the latter end of July. the danger of dislocating the machinery by the jolting of the stage will render a conveyance hither by water safest. accept my friendly salutations.