one of the last injunctions of our excellent & ever to be cherished friend Mr Corrêa, was, that I should send a small quantity of the ashes of Salsola kali to Dr Cooper, that he might learn whether it contain as much Soda when growing remote from the sea, as when contiguous to it. The season being rather far advanced for a fair experiment even when I returned to Richmond, I lost little time in preparing the ashes. I have been able however to think of no opportunity for conveying them to Dr C. so safe, as that afforded by your grand-son who goes to Columbia; may I therefore ask of you the favor to forward it by him. Your esteem for Mr. Correa, as well as your love of the Sciences, I am sure will interest you in the experiment.