SPEECH OF PROF. WILLIAMSON. 38T 



taneous with the discoveries of the materials themselves ; and the 

 material and intellectual progress of organic chemistry have gone 

 on so regularly hand in hand that it is impossible to say which has 

 done most in helping the other. It is, accordingly, observed that 

 the science has been simplified by every important addition to her 

 materials; instead of isolated unmeaning substances, with formulae 

 so complex and unintelligible as to be troublesome to chemists and 

 truly distressing to learners, we have now definite and intelligible 

 families of bodies, cf which the members are most harmoniously 

 united together by some law of composition, and whose connection 

 with neighbouring families is similarly clear and satisfactory. New 

 discoveries are constantly coming in to fill up the gaps which still 

 disfigure our growing system. In mineral, or inorganic chemistry, 

 there is not the same scope for discovering at present, inasmuch as 

 the elements which belong to it do not combine in those numerous 

 proportions which occur among the chief elements of organic bodies. 

 But yet, mineral chemistry has not been standing still : for even 

 the heavy metals most remote in their properties from those volatile 

 and unstable substances of organic chemistry, have been got in 

 many instances to combine with them ; and the organo-metallic 

 bodies thus formed have not only proved most valuable and powerful 

 agents of decomposition, but they have served as a connecting link 

 between the two branches of chemical science. A system of classifi- 

 cation of elements is now coming into use, in which the heavy 

 metals arrange themselves harmoniously with the elements of 

 organic bodies, and in accordance with the principles which were 

 discovered by a study of organic compounds. It is now many years 

 since the attention of chemists was directed by a French professor 

 to some inconsistencies which had crept into our system of atomic 

 weights. Gerhardt showed that the principles which were adopted 

 in fixing the atomic weight of elementary bodies generally required 

 (Us to adopt for oxygen, carbon, and sulphur numbers twice as great 

 ;as those generally in use for those elements. The logic of his argu- 

 ments was unanswerable ; and yet Gerhardt's conclusions gained 

 but few adherents. It is to be observed that for some years Ger- 

 hardt represented chemical reactions by so-called synoptic form- 

 ulae, which took no account of the existence of organic radicles. 

 These synoptic formulae represent in the simplest terms the result 

 •of a chemical reaction ; but they give no physical image of the pro- 

 gress by which the reaction is brought about. The introduction, in 

 this country,of the water-type in connectionwith poly-atomic as well 



