_B._ As for oil I never saw any inflamed by itself, how much soever heated, therefore I do not think they are the parts of the oil, but of the combustible body oiled that shine; but the parts of wine and strong drinks have partly a strong motion of themselves, and may be made to shine, but not with boiling, but by adding to them as they rise the flame of some other body. _A._ How can it be known that the particles of wine have such a motion as you suppose? _B._ Have you ever been so much distempered with drinking wine, as to think the windows and table move? _A._ I confess, though you be not my confessor, I have; but very seldom; and I remember the window seemed to go and come in a kind of circling motion, such as you have described. But what of that? _B._ Nothing, but that it was the wine that caused it; which having a good degree of that motion before, did, when it was heated in the veins, give that concussion, which you thought was in the window, to the veins themselves, and, by the continuation of the parts of man’s body, to the brain; and that was it which made the window seem to move. _A._ What is flame? For I have often thought the flame that comes out of a small heap of straw to be more, before it hath done flaming, than a hundred times the straw itself. _B._ It was but your fancy. If you take a stick in your hand by one end, the other end burning, and move it swiftly, the burning end, if the motion be circular, shall seem a circle; if straight, a straight line of fire, longer or shorter, according to the swiftness of the motion, or the space it moves in. You know the cause of that. _A._ I think it is, because the impression of that visible object, which was made at the first instant of the motion, did last till it was ended. For then it will follow that it must be visible all the way, the impressions in all points of the time being equal. _B._ The cause can be no other. The smallest spark of fire flying up seems a line drawn upward; and again by that swift circular motion which we have supposed for the cause of light, seems also broader than it is. And consequently the flame of every thing must needs seem much greater than it is. _A._ What are those sparks that fly out of the fire? _B._ They are small pieces of the wood or coals, or other fuel loosened and carried away with the air that cometh up with them. And being extinguished before their parts be quite dissipated into others, are so much soot, and black, and may be fired again. _A._ A spark of fire may be stricken out of a cold stone. It is not therefore heat that makes this shining. _B._ No it is the motion that makes both the heat and shining; and the stroke makes the motion. For every of those sparks, is a little parcel of the stone, which swiftly moved, imprinteth the same motion into the matter prepared, or fit to receive it.