MECHANICS AND USEFUL AKTS. 21 



facilities in the methods of analysis which were introduced by Liebig. Before 

 his time the determination of the component elements of an organic substance 

 was a task of so much skill as well as labor, that only the most accomplished 

 analysts such men, for instance, as Dr. Prout, or the great Berzelius 

 could be depended upon for such a work ; and hence the data upon which we 

 could rely for deducing any general conclusions went on accumulating with 

 extreme slowness. But the new methods of analysis invented by Liebig 

 have so simplified and so facilitated the process, that a student, after a few 

 months' practical instruction in a laboratory, can, in many instances, arrive at 

 results sufficiently precise to be made the basis of calculation, and thus to 

 enable the master mind, which is capable of availing itself of the facts before 

 it. to breathe life into these dry numerical details. And as the established 

 laws and institutions of the Old World have been modified may I not say in 

 some instances rectified ? by the insensible influence of those of the New, so 

 have the principles that had been deduced from the phenomena of the mineral 

 kingdom undergone in many instances a correction from the new discoveries 

 made in the chemistry of the animal and vegetable creation. It was a great 

 step indeed in the progress of the science, when Lavoisier set the example of 

 an appeal to the balance in all our experimental researches, and the Atomic 

 Theory of Dalton may be regarded as the necessary, although somewhat tardy, 

 result of the greater numerical precision thus introduced. But no less impor- 

 tant was the advance achieved, when structure and polarity were recognised 

 as influencing the condition of matter, and when the nature of a body was felt 

 to be determined, not only by the condition of its component elements, but 

 also by their mutual arrangement and collocation a principle which, first 

 illustrated amongst the products of organic life, has since been found to extend 

 alike to ah 1 chemical substances whatever. 



Formerly it had been the rule to set down the bodies which form the con- 

 stituents of the substances we analysed, and which had never yet under our 

 hands undergone decomposition, as elementary ; but the discovery of cyano- 

 gen in the first instance, and the recognition of several other compound 

 radicals in organic chemistry more lately, naturally suggest the idea that 

 many of the so-called elements of inorganic matter may likewise be compounds, 

 differing from the organic radicals above mentioned merely hi then' consti- 

 tuents being bound together by a closer affinity. And this conjecture is 

 confirmed by the curious numerical relations subsisting between the atomic 

 weights of several of these supposed elements ; as, for example, between 

 chlorine, bromine, and iodine ; an extension of the grand generalization of 

 Dalton. which, although it might very possibly have been repudiated by him, 

 had it been proposed for his acceptance, will be regarded by others as esta- 

 blishing, in a manner more conclusive than before, the soundness of his ante- 

 cedent deductions. 



"What, indeed, can be a greater triumph for the theorist, than to find that a 

 law of nature winch he has had the glory of establishing by a long process of 

 induction, not only accommodates itself to all the new facts which the progress 

 of discovery has since brought to light, but is itself the consequence of a still 

 more general and comprehensive principle, which philosophers, even at this 



