Another no small proof of this, is what Mr. _Freke_ has mentioned, viz. that in the year 1703, in the night of the great hurricane and high wind, in the strongest part of the tempest, great quantities of fire were seen passing swiftly over the hills in the neighbourhood of _Warham_ in _Dorsetshire_. The cause of which fire seems very easily accounted for, according to the above theory, which might otherwise perhaps, elude the searches of our greatest philosophers: for in this phænomenon it is plain, that the attrition of the particles of the air was so great by the motion of the wind, as to produce fire or light. Mr. _Freke_ has some other observations, which much strengthen the above theory, viz. that in tempestuous weather, at sea, great flakes of fire are frequently seen passing, not only in the air, but on the water. The like is also observed, in the night time, when the surface of the water is disturbed with the feathering of oars, or by a vessel or boat passing swiftly through it. This light or fire _in storms_ is no new observation; for Mr. _Boyle_ says, it is common in storms for the fire called _Helena_, _Castor_, and _Pollux_, to hover about the masts of ships. And, indeed, To shew that fire or heat are produced in any place, or thing, where there is a sufficient motion, seems not to be very difficult; for water is the opposite to fire; and yet, by mixing water and spirit of wine _suddenly_ together, a heat ensues; and this will happen if they have been separated ever so often; but this heat vanishes again after they are mixed, or as soon as the _motion_ of their parts ceases. The like will happen by mixing salt of tartar and water. This phænomenon seems to proceed from the disposition and texture of the salt; whose pores are made of such a proper size, that, on receiving the water by the pressure of the atmosphere into them, the texture of the salt may be thereby broken, and its parts put _into motion_; which _motion_ causes an _attrition_ of the air, and so produces a sensible heat.