TO JONATHAN WILLIAMS.

Monticello, July 3,1796.

Dear Sir,

I take shame to myself for having so long left unanswered your valuable
favor on the subject of the mountains. But in truth, I am become lazy as
to every thing except agriculture. The preparations for harvest, and
the length of the harvest itself, which is not yet finished, would have
excused the delay however, at all times and under all dispositions. I
examined, with great satisfaction, your barometrical estimate of the
heights of our mountains; and with the more, as they corroborated
conjectures on this subject which I had made before. My estimates
had made them a little higher than yours (I speak of the Blue Ridge.)
Measuring with a very nice instrument the angle subtended vertically
by the highest mountain of the Blue Ridge opposite to my own house,
a distance of about eighteen miles south westward, I made the highest
about two thousand feet, as well as I remember, for I can no longer find
the notes I made. You make the south side of the mountain near Rockfish
Gap, one thousand seven hundred and twenty-two feet above Woods. You
make the other side of the mountain seven hundred and sixty-seven feet.
Mr. Thomas Lewis, deceased, an accurate man, with a good quadrant, made
the north side of the highest mountain opposite my house something more
(I think) than one thousand feet; but the mountain estimated by him and
myself is probably higher than that next Rockfish Gap. I do not remember
from what principles I estimated the Peaks of Otter at four thousand
feet; but some late observations of Judge Tucker's coincided very nearly
with my estimate. Your measures confirm another opinion of mine that
the Blue Ridge, on its south side, is the highest ridge in our country
compared with its base. I think your observations on these mountains
well worthy of being published, and hope you will not scruple to let
them be communicated to the world.

You wish me to present to the Philosophical Society the result of my
philosophical researches since my retirement. But, my good Sir, I have
made researches into nothing but what is connected with agriculture.
In this way, I have a little matter to communicate, and will do it ere
long. It is the form of a mould-board of least resistance. I had some
years ago conceived the principles of it, and I explained them to Mr.
Rittenhouse. I have since reduced the thing to practice, and have reason
to believe the theory fully confirmed