EXTRACTS FROM " MICROGRAPHIA." 1 79 



melt a body. Now that I do not speak of this altogether 

 groundless, I must refer the Reader to the Observations I 

 have made on the shining sparks of Steel, for there he shall 

 find that the same effects are produced upon small chips 

 or parcels of Steel by the flame and by a quick and violent 

 motion ; and if the body of Steel may thus be melted (as I 

 there show it may) I think we have little reason to doubt 

 that almost any other may not also. Every Smith can inform 

 one how quick both his File and the Iron grow hot with 

 filing y and if you rub almost any two hard bodies together 

 they will do the same, and we know that a sufficient degree 

 of heat causes fluidity in some bodies much sooner and in 

 others later ; that is the parts of some are so loose from one 

 another and are so unapt to coJiere, and so minute and little, 

 that a very small degree of agitation keeps them always in 

 a state of fluidity. Of this kind, I suppose the yEther, that 

 is the medium or fluid body in which all other bodies do as 

 it were swim and move, and particularly the air."— (7£. 

 p. 16.) " Now that the parts of all bodies, though never so 

 solid, do yet vibrate, I think we need go no further for proof 

 than that all bodies have some degree of heat in them, and 

 that there has not been yet found anything perfectly cold. 

 Nor can I believe indeed that there is any such thing in 

 Nature as a body, whose particles are at rest or lazy and 

 unactive in the great Theatre of the World, it being quite 

 contrary to the grand (Economy of the Universe." 



Extract from " Micrographia," p. 44. : — 



"It is a very common Experiment, by striking with a 

 Flint against a Steel, to make certain fiery and shining 

 sparks to fly out from between those two compressing 

 Bodies. 



