Your favor of Jan. 23. was recd yesterday only. the facts mentioned in it had never fallen under my observn, and consequently had never been the subject of my considn. were I better acqd with the structure of light houses or of the lanterns used in them, of both of which I am entirely ignorant, yet I have been too long unfamiliarised with speculns of that nature and am too heavily pressed by the hand of age to hazard any hypothesis explanatory the facts.  your idea of keeping the oil pilloried by the warmth of the lamp itself is ingenious plausible & valble and I wish success to the process you propose as well on your own account as that of the benighted mariner with assurances of my esteem & respect