or Worked out by the late Br Front. 99 



attainments can now, after a few months' training, complete 

 an analysis, which may be appealed to with confidence, and 

 received as the basis of further research ; whereas before, 

 only adepts in chemistry were capable of bringing out results 

 upon which any reliance could be placed. 



Yet the greater part of Dr Prout's analyses were made 

 with an apparatus of his own, which, however ingenious it 

 might be, was far more difficult to use, and required for its 

 success many more precautions than that at present in the 

 hands of chemists, and hence the precision to which he at- 

 tained is the greater subject for commendation. Add to 

 which, that these delicate investigations were carried on by 

 him, unassisted, amid constant interruptions, at intervals 

 snatched from the daily demands made upon his time by pro- 

 fessional engagements. 



The second characteristic of his genius was that power of 

 generalisation, that aptitude of combining into an harmonious 

 whole, a number of isolated and independent facts, which led 

 him to seize upon the remote consequences deducible from 

 the results of his own observations, as well as those of others, 

 and at the same time to shape his inquiries in such directions 

 as might lead to the development of great principles in 

 science. Thus, for instance, so far back as the year 1815, 

 he published that remarkable paper, " On the relation be- 

 tween the Specific Gravity of Bodies in their Gaseous State, 

 and their Atomic Weights," in which he pointed out, within 

 a few years after the promulgation of the Daltonian theory, 

 that the atomic weights of all other bodies may be regarded 

 as multiples of that of hydrogen, — a position which, after 

 being disputed by Berzelius and other great authorities, came 

 at length to be confirmed with respect to three of the most 

 important elements — carbon, oxygen, and azote — by the re- 

 searches of Dumas and others. 



Thus, at a later period, his delicate method of weighing 

 the air enabled him to suggest a cause for the prevalence of 

 the cholera then raging in London — namely, the addition of 

 an ingredient to the ordinary constituents of the atmosphere, 

 which increased the specific gravity of its lower strata over 

 that locality. 



g2 



