Front Page Titles (by Subject) XXXV: TO CADWALLADER COLDEN - The Works of Benjamin Franklin, Vol. II Letters and Misc. Writings 1735-1753
Return to Title Page for The Works of Benjamin Franklin, Vol. II Letters and Misc. Writings 1735-1753
The Online Library of Liberty
A project of Liberty Fund, Inc.
XXXV: TO CADWALLADER COLDEN - Benjamin Franklin, The Works of Benjamin Franklin, Vol. II Letters and Misc. Writings 1735-1753 
The Works of Benjamin Franklin, including the Private as well as the Official and Scientific Correspondence, together with the Unmutilated and Correct Version of the Autobiography, compiled and edited by John Bigelow (New York: G.P. Putnam’s Sons, 1904). The Federal Edition in 12 volumes. Vol. II (Letters and Misc. Writings 1735-1753).
About Liberty Fund:
Liberty Fund, Inc. is a private, educational foundation established to encourage the study of the ideal of a society of free and responsible individuals.
The text is in the public domain.
Fair use statement:
This material is put online to further the educational goals of Liberty Fund, Inc. Unless otherwise stated in the Copyright Information section above, this material may be used freely for educational and academic purposes. It may not be used in any way for profit.
TO CADWALLADER COLDEN
I received yours with others enclosed for Mr. Bartram and Mr. Armit, to which I suppose the enclosed are answers. The person who brought yours said he would call for answers, but did not; or if he did, I did not see him.
I understand Parker1 has begun upon your piece. A long sitting of our Assembly has hitherto hindered me from beginning the Miscellany. I shall write to Dr. Gronovius as you desire.
I wish I had mathematics enough to satisfy myself whether the much shorter voyages made by ships bound hence to England, than by those from England hither, are not in some degree owing to the diurnal motion of the earth, and if so, in what degree. It is a notion that has lately entered my mind; I know not if ever any other’s. Ships in a calm at the equator move with the sea fifteen miles per minute; at our Cape suppose twelve miles per minute; in the British Channel suppose ten miles per minute. Here is a difference of two miles’ velocity per minute between Cape Henlopen and the Lizard. No small matter in so weighty a body as a laden ship swimming in a fluid. How is this velocity lost in the voyage thither, if not by the resistance of the water? And if so, then the water, which resisted in part, must have given way in part to the ship, from time to time, as she proceeded continually out of parallels of latitude where the earth’s motion or rotation was quicker, into others where it was slower. And thus, as her velocity tends eastward with the earth’s motion, she perhaps makes her easting sooner. Suppose a vessel lying still in a calm at our Cape could be taken up, and the same instant set down in an equal calm in the English Channel, would not the difference of velocity between her and the sea she was placed in appear plainly by a violent motion of the ship through the water eastward?
I have not time to explain myself farther, the post waiting; but I believe I have said enough for you to comprehend my meaning. If the reasons hinted at should incline you to think there is any thing in this notion, I should be glad of an answer to this question, if it be capable of a precise answer, viz.
Suppose a ship sails in a northeast line from latitude 39 to latitude 52, in thirty days, how long will she be returning on the same line, winds, currents, etc., being equal? Just so much as the eastern motion of the earth helps her easting, I suppose it will hinder her westing. Perhaps the weight and dimensions or shape of the vessel should be taken into consideration, as the water resists bodies of different shapes differently.
I must beg you to excuse the incorrectness of this scrawl, as I have not time to transcribe. I am, Sir,
Your most humble servant,
[1 ]A printer in New York.