OF SOLIDS AND LIOUID&. 241 



pressure upwards, or levity, is the natural test 

 of the rarity of their composition, with relation 

 to the density of the medium which they have 

 displaced. Matter is not dense, because it is 

 heavy ; nor rare, because it is light ; it is not 

 expansible, because it is motive; nor motive, be- 

 cause it excites illumination. Those who form 

 these notions, have viewed the subject in an 

 improper manner ; they ascribe to effects the 

 power of cause they mistake the shadow for 

 the substance the secondary and accidental 

 property of matter, for that which is primary 

 and essential. 



It ought, on the contrary, to be stated, that 

 matter is heavy, because it is dense ; that it is 



a quantity of base metal, or alloy, ordered Archimedes, to 

 verify the fact, without mutilating the crown. After much 

 deliberation on the subject, it occurred to him, at the time 

 he was in a bath, that his body was much lighter in water, 

 than it was in air ; and that the cause of this difference, must 

 arise from the difference between the density of the medium of 

 water, and of air; he, therefore, ordered a crown of pure 

 gold to be made, which balanced the other in the air : but 

 upon weighing them both together in water, he found that 

 the first was much lighter than the second; consequently, 

 that that difference must have arisen from its containing mat- 

 ter in it, less dense than gold. It is added, that Archimedes 

 was so enraptured with the discovery which he had made, 

 that he forgot that he was naked at the time ; and had the 

 indecency to run through the city in that condition, crying out, 

 I have found it, I have found it ! ! ! 



R 



