Ben Franklin writes Vattel's Law of Nations was frequently consulted. It defines natural born: US born of citizen parents

Benjamin Franklin to To: Charles William Frederic Dumas

Dear Sir,
Philadelphia, 9 December, 1775.

I received your several favors, of May 18th, June 30th, and July 8th, by Messrs. Vaillant and Pochard;(1) whom if I could serve upon your recommendation, it would give me great pleasure. Their total want of English is at present an obstruction to their getting any employment among us; but I hope they will soon obtain some knowledge of it. This is a good country for artificers or farmers; but gentlemen of mere science in les belles lettres cannot so easily subsist here, there being little demand for their assistance among an industrious people, who, as yet, have not much leisure for studies of that kind.

I am much obliged by the kind present you have made us of your edition of Vattel. It came to us in good season, when the circumstances of a rising state make it necessary frequently to consult the law of nations. Accordingly that copy, which I kept, (after depositing one in our own public library here, and sending the other to the College of Massachusetts Bay, as you directed,) has been continually in the hands of the members of our Congress, now sitting, who are much pleased with your notes and preface, and have entertained a high and just esteem for their author. Your manuscript "Idee sur le Gouvernement et la Royaute" is also well relished, and may, in time, have its effect. I thank you, likewise, for the other smaller pieces, which accompanied Vattel. "Le court Expose de ce qui s'est passe entre la Cour Britannique et les Colonies," bc. being a very concise and clear statement of facts, will be reprinted here for the use of our new friends in Canada. The translations of the proceedings of our Congress are very acceptable. I send you herewith what of them has been farther published here, together with a few newspapers, containing accounts of some of the successes Providence has favored us with. We are threatened from England with a very powerful force, to come next year against us.(2) We are making all the provision in our power here to oppose that force, and we hope we shall be able to defend ourselves. But, as the events of war are always uncertain, possibly,

http://etext.lib.virginia.edu/etcbin/toccer-new2?id=DelVol02...

http://constitutionallyspeaking.wordpress.com/bho-the-stubbo...

Def of natural born in Vattel's Law of Nations:
http://www.obamacitizenshipfacts.org/