Th: Jefferson returns his thanks to mr Fennel for the Dissertation on his method of making salt. the theory is certainly promising. what may be the actual result depends on so many circumstances as to require experiment to found an estimate. having no experience on the subject himself, he is entirely unable to give an opinion: but doubts not that mr Fennel has sufficiently verified his process by experiment to justify his conclusions. he sincerely wishes him success, and apprehends the circumstances of the times are likely to befriend his undertaking.