New york, July 1. 1805
I beg you, Sir, to inform our friend T. M. Randolph that I have made a number of experiments upon the saline Substance which you forwarded to me. He is right in his judgment that the mass is a mixture of different salts. The trials I have made warrant the conclusion that there are three compound salts, to wit, Sulphate of Magnesia, Sulphate of Soda, and Muriate of Soda.
The first, which is the Epsom Salt of the English, or the bitter cathartic Salt of the shops, is the irredominating Article. The second, which is the Sal mirabilis or Glauber’s Salt is the next in quantity. The proportion of the third or common Kitchen salt seems to be very inconsiderable. The present hot Season being unfavourable to chrystallization, I have not made any attempt to determine the proportions of the several ingredients; tho there can be no doubt that the first is by a great difference the most abundant: and that the last is very trifling.
I do not find any more than the faintest Vestiges of Lime. Nor are the evidences any stronger in favour of the acid of Salt-petre.
It does not appear to me from the Sample that it contains any Saltpetre, and if the proprietor continues to work it, he must do so for the sake of the Epsom Salt.
I am sure to be pardoned for these details by him whose love of general Science, and whose labours to illustrate the History of Virginia, have rendered him famous not only in his own Country, but throughout the civilized world abroad.
I have seen Mr. R. R. Livingston since his arrival; and think he looks remarkably well.
Respectfully & truly yours
Sam L Mitchill
DLC: Papers of Thomas Jefferson.