To Cadwallader Colden
[Enclosure] Answer to the foregoing Observations

I agree with you, that it seems absurd to suppose that a Body can act where it is not. I have no Idea of Bodies at a Distance attracting or repelling one another without the Assistance of some Medium, tho’ I know not what that Medium is, or how it operates. When I speak of Attraction or Repulsion I make use of those Words for want of others more proper, and intend only to express Effects, which I see, and not Causes, of which I am ignorant. When I press a blown Bladder between my Knees, I find I cannot bring its Sides together, but my Knees feel a Springy Matter pushing them back to a greater Distance, or repelling them. conclude that the Air it contains is the Cause. And when I operate on the Air, and find I cannot by Pressure force its Particles into Contact, but they still spring back against the Pressure, I conceive there must be some Medium between its Particles that prevents their Closing, tho’ I cannot tell what it is. And if I were acquainted with that Medium, and found its Particles to approach and recede from each other according to the Pressure they suffer’d, I should imagine there must be some finer Medium between them by which these Operations were performed.

I allow that increase of the Surface of a Body may occasion it to descend slower in Air, Water, or any other Fluid; but do not conceive therefore that it lessens its Weight. Where the increas’d Surface is so dispos’d as that in its falling a greater Quantity of the Fluid it sinks in must be moved out of its Way, a greater Time is required for such Removal. Four square Feet of sheet Lead sinking in Water broadways, cannot descend near so fast as it would edgeways, yet its Weight on the Hydrostatic Ballance would I imagine be the same, whether suspended by the Middle or by a Corner.

I make no doubt but that Ridges of high Mountains do often interrupt, stop, reverberate or turn the Winds that blow against them, according to the different degrees of Strength of the Winds, and the Angles of Incidence. I suppose too, that the cold upper Parts of Mountains may condense the warmer Air that comes near them, and so by making it specifically heavier, cause it to descend on one or both sides of the Ridge into the warmer Valleys, which will seem a Wind blowing from the Mountain.

Damp Winds tho’ not colder by the Thermometer, give a more uneasy sensation of Cold than dry ones. Because (to speak like an Electrician), they conduct better, that is, are better fitted to convey away the Heat from our Bodies; The Body cannot feel without itself; Our Sensation of Cold is not in the Air without the Body, but in those Parts of the Body which have been depriv’d of their Heat by the Air. My Desk and its Lock are, I suppose of the same temperament when they have long been expos’d to the same Air; but now, if I lay my Hand on the Wood, it does not seem so cold to me as the Lock; because (as I imagine) Wood is not so good a Conductor to receive and convey away the Heat from my Skin and the adjacent Flesh, as Metal is. Take a Piece of Wood of the Size and Shape of a Dollar between the Thumb and Fingers of one Hand, and a Dollar in like manner with the other Hand; place the Edges of both at the same time in the Flame of a Candle; and tho’ the Edge of the wooden Piece takes Flame and the metal Piece does not, yet you will be oblig’d to drop the latter before the former, it conducting the Heat more suddenly to your Fingers. Thus we can without Pain handle Glass and China Cups fill’d with hot Liquors, as Tea, &c. but not silver ones. A Silver Teapot must have a Wooden Handle. Perhapts it is for the same Reason that woolen Garments keep the Body warmer than Linen ones equally thick. Woolen keeping the Natural Heat in, or, in other Words, not conducting it out to Air.

In Regard to Waterspouts, having in a long Letter to [a] Gentleman of the same Sentiment with you as to their Direction said all that I have to say in support of my Opinion, I need not repeat the Arguments therein contain’d, as I intend to send you a Copy of it, by some other Opportunity for your Perusal. I imagine you will find all the Appearances you saw, accounted for by my Hypothesis. I thank you for communicating this Account of them. At present I would only say, that the Opinion of Winds being generated in Clouds by Fermentation, is new to me, and I am unacquainted with the Facts on which it is founded: I likewise find it difficult to conceive of Winds confin’d in the Bodys of Clouds, which I imagine have little more solidity than the Fogs on the Earth’s Surface. The Objection from the Freshness of Rain Water is a strong one, but I think I have answered it in the Letter above mentioned, to which I must beg Leave at present to refer you.

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