Washington Nov. 16. 08.
I am extremely satisfied with Dr. Franklin’s method of fixing the spectacles, by composing each glass of two half glasses of different magnifying powers, and those you made for me answer perfectly except that the frames being circular, the glasses are always twisting round & bringing the seam between the two halfglasses in the way of the eye. to prevent this the frame should be oval. I send you therefore the oval frame you last made for me, being much approved in their size, and I pray you to furnish a set of half glasses for them, from the magnifying power of the glasses now in them up to the greatest. those now in them suit the present state of my vision. I think the larger of the two magnifiers put into the same frame should differ but a single number from each other, the largest magnifier being uppermost. altho these glasses are very small, & consequently the half glasses uncommonly so, I am not afraid but that they will present full space enough for reading, writing &c as I am satisfied that the pencil of rays in these cases occupies little more than a speck on the glass. the spectacles may be safely returned by post, if done up in the way they now are. be so good as to send with them a note of the cost, of which I will direct paiment to be made. I salute you with esteem.
DLC: Papers of Thomas Jefferson.