Congress having referred to me a petition from a person of the name of Isaacs, setting forth that he has discovered an easy method of rendering sea-water potable, I have had a cask of sea-water procured, and the petitioner has erected a small apparatus in my office, in order to exhibit his process. Monday morning 10. aclock is fixed on as the time for doing it. It would give me great satisfaction to be assisted on the occasion by your chemical knowlege, and the object of the letter I now take the liberty of writing is to ask whether it would be convenient for you to be present at the time and place beforementioned; which, besides contributing to a public good, will much oblige Sir Your most obedt. & most humble servt,