DIFFICULTIES CAUSED BY UNRIPENESS OF CONDITIONS. 217 



is not until the fullest proof is obtained that we become in 

 a very high degree certain. When Newton, in 1666, first 

 attempted to test his assumed law of action of gravity, he 

 only obtained an approximate result, because his only 

 available data were not sufficiently accurate. 



Discovery by synthesis is more difficult than that by 

 analysis. It is more difficult to build up than to pull 

 down. The former is a more systematic procedure, and 

 requires more preparation and a more intelligent mind. 

 We accordingly find that in the early stages of knowledge 

 of chemistry new discoveries were chiefly made by de- 

 composing bodies by means of heat, &c. ; but in later 

 periods we have acquired a gradual insight into various 

 methods by which compound substances may be formed, 

 and we have at length succeeded in constructing from their 

 elementary constituents many substances, such as urea, 

 uric acid, alizarine, and others, which were formerly be- 

 lieved to be formed in plants and animals alone, and to be 

 obtainable only by the analysis or decomposition of animal 

 and vegetable products. It may also be remarked, that 

 whilst we have numerous treatises on chemical analysis we 

 have scarcely any on chemical synthesis only; we have 

 constructed a more complete system of the former than of 

 the latter. 



A circumstance which has added amazingly to the diffi- 

 culty of original scientific research, has been the entire 

 absence of remuneration for the very large amount of time 

 and labour expended upon it, and the imperfect provision 

 for repayment of money expended upon apparatus and 

 materials. M. Fremy, speaking of the deficiency of en- 

 couragement of original scientific research, says : ' The evil 

 will not be eradicated until scientific careers are regularly 

 organised and properly recruited. It must not be forgotten 

 that at the present day, more than ever, every career with- 



