48 Brown^s Microscopical Observations, < 



to decided minerals, and the first substance examined was a 

 minute fragment of window-glass, from which, when merely 

 bruised on the stage of the microscope, he readily and 

 copiously obtained molecules agreeing in size, form, and mo- 

 tion, with those he had already seen. Metals, volcanic ashes, 

 meteorites, rocks of all ages, granite itself, and, lastly, a frag- 

 ment of the Sphinx in the British Museum, yielded the mole- 

 cules in abundance. The dust, or soot, so miserably abundant 

 in London, is entirely composed of these molecules, possessing 

 visible, rapid, spontaneous, or inherent motion. 



In many of the substances examined, especially those of 

 a fibrous structure, such as Asbestos, along with the spherical 

 molecules other corpuscles were found, like short fibres, 

 somewhat moniliform, whose transverse diameter appeared not 

 to exceed that of the molecules, of which they seemed to be 

 primary combinations. These fibrils, when of such length as 

 to be probably composed of not more than four or five mole- 

 cules, and still more evidently when formed of two or three 

 only, were generally in motion, at least as vivid as that of the 

 simple molecule itself; and which, from the fibril often 

 changing its position in the fluid, and from its occasional 

 bending, might be said to be somewhat vermicular. 



In many instances oval particles were perceived, which 

 seemed to consist of a simple combination, perhaps of two 

 molecules, and these possessed a motion generally more vivid 

 than that of the simple molecule ; their motion consisting in 

 turning usually on their longer axis. 



, The author is disposed to beHeve that the ultimate mole- 

 cule, if we may so speak, is of uniform size in all bodies. Mr. 

 Brown does not pretend that his facts relative to the particles 

 of pollen are wholly original: but that still more curious 

 (because more elementary and remote) existence of molecules 

 in all organic and inorganic bodies, possessing an inherent 

 motion, not to say voluntary ; and, in simple combinations, a 

 motion of two kinds at the same time (the one ambulatory, 

 and the other on its own axis), is wholly, entirely, and undi- 

 videdly his own. 



No Englishman has dared to set up any claim to a fraction, 

 not even a molecule, of this extraordinary discovery ; and if 

 there be those abroad, who now insinuate that the theories 

 they have propounded to explain the motion of the particles 

 of pollen, necessarily prove that they knew of, saw, and com- 

 passed these molecules, it only shows how much more im- 

 portance they attach to theory than«to experiment, and how 

 little justice they are disposed to concede to an observer, who 

 is behind none in doing justice to them. O. 



