144 MEMOIR OF DR. DALTON, AND 



those speculations about the constitution of bodies which in 

 former chapters have been passed over. I may indeed cite 

 here Roger Bacon's syntheses of bodies from the four elements, 

 as the earliest examples of an endeavour to shew how so many 

 bodies can be formed from few elements, and on the other 

 side, as the fullest example I know of early analysis, and 

 perhaps the very first in which numbers are used in connection 

 with elements. They are intellectual strivings after quanti- 

 tative analysis. 



" There is, therefore, one different kind where fire and air 

 are greater ; 2ndly, where fire and air are less ; 3rd, where 

 fire and water are greater ; 4th, where fire and water are less ; 

 5th, where fire and earth are greater; 6th, where fire and 

 earth are less; 7th, where air and water are greater; 8th, 

 where air and water are less; 9th, where air and earth are 

 greater; 10th, where air and earth are less; 11th, where 

 water and earth are greater; 12th, where water and earth are 

 less ; and so you have two diversities. Next you have three 

 diversities; 1st, where fire, air, and water are greater; 2nd, 

 where fire, air, and water are less ; 3rd, where air, water, and 

 earth are greater; 4th, where fire, water, and earth are 

 greater; 5th, where air, water, and earth are less; 6th, where 

 fire, water, and earth are less; and in this manner, if you 

 divide those methods, you obtain from the first 16, from the 

 second 64, from the third 47> from the fourth 18, in all 145. 

 I will now speak of the fourth diversity, fire much, air less, 

 water much, earth less ; second, air much, water less, earth 

 less, fire less, and so being ingenious, you may draw out all 

 these diversities to light." 



A manuscript copy of Dr. CuUen's lectures in 1762-3 in 

 the laboratory of Owens College, Manchester, from the late 

 Dr. Henry's library, mentions four elements, which, by 

 simple combination, could be formed into seven, but any 

 proportionate combination to account for the number in 

 nature, is not given. 



