HI8T0EY OF THE ATOMIC THEORY. 175 



they deserve only a part. As far as our subject is concerned 

 Dr. Higgins has small claims. His opinions on atoms might 

 have been held by the ancients: whilst standing on their 

 shoulders, it would have required much less sagacity to 

 discover than was needed for them. He speaks of the sums 

 of the forces of atoms measuring the attraction of matter, but 

 does not suppose that if matter be atomic, the number of 

 atoms might also, in this way, be got comparatively. 



We might say, however, that Di|^ Higgins began the study 

 of atomic chemistry, properly so called, although he made 

 little advance in it. 



The next person worthy of note is of the same name and 

 family. The following extracts contain what is of greatest 

 importance in connection with our subject. The title page of 

 the volume quoted from is, "A Comparative View of the 

 Phlogistic and Antiphlogistic Theories, with Inductions, &c., 

 by William Higgins, of Pembroke College, Oxford. The 

 Second Edition. 



" Est quoddam prodire tenus, si non datur ultra. 



" London : Printed for J. Murray, No. 32, Fleet Street. 

 1791." The first edition was in 1789. 



Page 14. " It is generally allowed, and justly, that nitrous 

 air consists of dephlogisticated air and phlogistic, in the pro- 

 portion of two of the former to one of the latter. The 

 supposition of its containing phlogiston, I Bope, will hereafter 

 appear to be erroneous ; therefore, every ultimate particle of 

 phlogisticated air must be united to two of dephlogisticated 

 air; and these molicules, combined with fire, constitute nitrous 

 air. Now, if every (one) of these molicules were surrounded 

 with an atmosphere of fire equal in size only to those of 

 dephlogisticated air, 100 cubic inches of nitrous air should 

 weigh 98,535 grains; whereas, according to Kirwan, they 

 weigh but 37 grains. Hence, we may justly conclude that 

 the gravitating particles of nitrous air are thrice the distance 

 from each other that the ultimate particles of dephlogisticated 



