120 MEMOIR OF DR. DALTON, AND 



phenomena, of any of his period. One feels, on reading his 

 works, that on another subject he might have written so as to 

 be even now and at all times read with delight, whereas, in the 

 dangerous and difficult fields of chemistry, he has only left 

 matter serving as landmarks, to shew us the way in which 

 the mind has been obliged to wander in search of truth. 



Boyle says, when treating of the " origin of form and quali- 

 ties," * " There is one universal matter common to all bodies, 

 an extended, divisible, and impenetrable substance." 



And in the " Sceptical Chemist." f " But the Aristotelian 

 hypothesis (i.e., of tlie four elements) is not comparable to the 

 mechanic doctrine of the bulk and figure of the smallest parts 

 of matter, for from these more universal and fruitful principles 

 of the elementary matter, may spring a great variety of 

 textures, upon whose account a multitude of compound bodies 

 might greatly differ from one another." In p. 282 : — " Now 

 if it be true, as 'tis probable, that compound bodies differ from 

 one another, in nothing but the various textures, resulting 

 from the magnitude, shape, motion, and arrangement of their 

 small parts, it will not be irrational to conceive that one and 

 the same particle of universal matter, may by various altera- 

 tions and contextures be brought to deserve the name some- 

 times of a sulphureous, and sometimes of a terrestrial or 

 aqueous body." 



He attacks severely the four elements, the three elements, 

 and the five elements, and justly complains of the " intolerable 

 ambiguity " of the writers on chemistry, and " their playing 

 upon words," as their mode of using salt, sulphur, and mercury 

 decidedly is. 



To continue from Boyle. " It seems probable that at the 

 first production of mixt bodies, the universal matter whereof 

 they consist was actually divided into little particles of several 



* Vol. I., p. 197. The philosophical works of the Hon. Robert Boyle, Esq. 

 Abridged, methodized, &c., by Peter Shaw, M.D. 2nd edition, 1738. 

 t Vol. III., p. 200. 



