Matthew Fontaine Maury¹ and George Manning² to Faraday   16 and 23 April 1851

National Observatory, | Washington D.C | April 16th 1851

My dear Sir,

I have recd your letter of the 24th Ulto with the Copy of the “Experimental researches in Electricity 24th 25th 26th & 27th Series”³ which you had the kindness to send, and for which I thank you most heartily[.]

I need not say how eagerly these several papers were devoured; I have studied them with profit and pleasure; and admired, step by step as I went along, the true spirit of philosophical research that pervades them.

To me, some of your results look very much like a cleu [sic] which you have placed in the hands of physicists to guide them through dark and doubtful places of research.

It may lead through many tortuous windings before it brings us to the end, but we look to you still further; You must not tire.

Will you not therefore embrace in your researches the electric or magnetic properties of Sea water at various temperatures? for it appears to me that our philosophy is as much at fault in accounting for the velocity of the Gulf Stream, as it is for the cause of magnetism.

The Mississippi river, where its fall has been computed at 2 1/2 inches to the mile, is said to have an hourly velocity of 1 1/2 miles. But, the Gulf Stream, running on a water level, maintains a velocity of 4, and reaches occasionally a velocity of 5 miles, an hour.

I am prepared to show that the Trade Winds have very little to do with giving direction and force the currents of the sea, and there is room for the conjecture that the submarine currents are as regular if not as active as those at the surface.

What is the cause of this great velocity of the Gulf stream on a water level? Not gravitation certainly[.]

The difference of Specific gravity between the hot waters of the Gulf stream and the cold waters of the poles would cause motion; but unless some other agent were concerned, not with such velocity as that of the Gulf Stream; nor can it be comprehended how, without the help of some other agent, the waters of the Gulf Stream should collect themselves together, and flow to the North in a body, as they do.

That the waters of the Gulf stream do not readily mingle with those of the ocean about them, we know; and if you will do me the favor to look at pp 15-20 “Investigations of the Winds and Currents of the Sea”⁴ several copies of which I have caused to be placed at your disposal, you will find some striking evidence of this fact.

Why is this? the very waters through which the Gulf Stream is flowing, are themselves bound down to the Trade Wind regions, to supply the air with vapor, to have their temperature raised, to enter the Gulf, to perform their circuit, and to issue thence as Gulf Stream water, invested with antagonistic principles - so to speak. Whence is this antagonism derived? meaning by Antagonism, in this place, simply the indisposition of the two waters - those flowing from the Gulf and those through which they flow, to commingle.

The reluctance of the waters of any two streams when they meet, to mingle is often manifested, and perhaps the display of this propensity by those of the Gulf Stream may not be considered remarkable, except as to distance and extent.

If you will look at the shape of the Gulf Stream you will be struck with its cuniform proportions; From the Straits of Bemini to the Grand Banks it is like a wedge, with its apex cleaving the Straits[.]

What has this form and pressure of the cold and therefore heavier waters which make the bed and banks of the Gulf Stream, to do with its velocity? Striking analogies might be pointed out in this connexion.

You will observe too, that according to the Storm tracks which meteorologists assign to the West India Hurricanes, those storms manifest by their course, a tendency towards the waters of the Gulf Stream, conforming with it in their general direction[.]

Can therefore the waters of this Stream, and the air above them, be more or less paramagnetic or diamagnetic, than the sea waters generally?

Why may not the oxygen of the water be paramagnetic, as well as the oxygen of the air? or are the gasses and salts of sea water capable of any magnetic influences? If the oxygen of the water be magnetic will not that of its vapor be magnetic also? If an affirmative reply be given to these interrogations, would it not be suggestive of the agency through which, or by which, the Gulf Stream rules the course of the Storm, and preserves its own peculiarities?

You will, I hope, understand me in making the above remarks, and in propounding the above interrogatories.

I make the remarks with the hope of interesting you, and of engaging your thoughts upon these captivating subjects; and I ask the questions, in the true spirit of philosophical inquiry, so well described in your 2702 et seq⁵, as moving you to your beautiful train of researches.

Will you not therefore - or is it your intention to do so, or would it be useless - to extend your “Researches in Electricity” to the sea, its gasses, & its salts, and its vapors, and determine as to the degree and nature of “Aqueous Magnetism” if there be such a thing.

Reading your remarks as to the great “Magnetic lense”⁶ which follows the sun through the atmosphere and studying the diagrams of magnetic declination at Toronto & St. Petersburg I was led to ask myself the question, What have the Gulf Stream and the mantle of warmth which it spreads over the extra tropical North and places between St. Petersburg and Toronto to do with the time and period of the great “sun swing”⁷ of the needle at the two places. One place has a great extent of land surface to the East - the other to the West and the two are separated by the warm waters of the Gulf Stream.

I hope you will pardon me for trying so earnestly to tempt you out to sea. I am there, and often find myself bewildered, and shall be most happy to come within your hail, and get fresh points of departure from you now and then[.]

Respectfully &c | M.F. Maury

To | M. Faraday Esq | Royal Institution | London

The charts &c referred to by Lieut Maury, will be forwarded to you in a package to John W. Parker⁸, Bookseller, if possible by next London Packet sailing of 24 inst -or 1st Prox.

Very truly &c &c | Geo Manning

New York April 23 / 51