TKANSACTIONS OF SECTION B. 709 



reserve material for subsequent use of the plant; or of Cross, Bevan, and Beadle, 

 on the interaction of alkali-cellulose and carbon bisulphide, in the course of which 

 they have proved that a cellulose residue can act like an alcohol radical in the 

 formation of thiocarbonates, and thus have added another to the authors' valuable 

 contributions to our knowledge of members of the complex group of celluloses. 



But it is now an idle task for a President of this Section to attempt a slight 

 sketch of the works of chemical philosophers even during the short space of tM'elve 

 months; they are too numerous and generally too important to be lightly treated, 

 hence we can but apply to them a paraphrase of the ancient formula — Are they 

 not written in the books of the chronicles we term ' Jahresberichte,' ' Annales,' or 

 'Transactions and Abstracts,' according to our nationality? 



I would, however, in this connection ask your consideration for a question re- 

 lating to the utilisation of the vast stores of facts laid up — some might even 

 say buried — in the records to which reference has just been made. The need exists, 

 and almost daily becomes greater, for facile reference to this accumulated wealth, 

 and of such a kind that an investigator, commencing a line of inquiry with whose 

 previous history he is not familiar, can be certain to learn all the facts known on 

 the subject up to a particular d ate, instead of having only the partial record to be 

 found in even the best edited of the dictionaries now available. The best and 

 most obvious method of attaining this end is the publication of a subject-matter 

 index of an ideally complete character. I am glad to know that the Chemical Society 

 of London will probably provide us in the years to come with a compilation which 

 will doubtless aim at a high standard of value as a work of reference to memoirs, 

 and in some degree to their contents, so far as the existing indexes of the volumes 

 of the Society's Journal supply the information. Whether this subject-matter 

 index is published or not, the time has certainly arrived for adopting the imme- 

 diately useful course of publishing monographs, analogous to those now usual in 

 Natural Science, which shall contain all the information gained up to a particular 

 date in the branch of chemistry' with which the author is specially familiar by 

 reason of his own work in the subject. Such monographs should include much 

 more than any mere compilation, and would form the best material from which a 

 complete subject-matter index might ultimately be evolved. 



ily attention was forcibly drawn to the need of such special records by noting 

 the comparatively numerous cases of re-discovery and imperfect identification of 

 derivatives of thiourea. In my laboratory, where this substance was isolated, we 

 naturally follow with interest all work connected with it, and therefore readily 

 detect lapses of the kind just mentioned. But when it is remembered that the 

 distinct derivatives of thiourea now known number considerably over six hundred 

 substances, and that their descriptions are scattered through numerous British and 

 foreign journals, considerable excuse can be found for workers overlooking former 

 results. The difficulty which exists in this one small department of the science I 

 hope shortly to remove, and trust that others may be induced to provide similar 

 works of reference to the particular branches of chemistry with which they are 

 personally most familiar. 



When we consider the drift of investigation in recent years, it is easy to recog- 

 nise a distinct reaction from extreme specialisation in the promineTice now given 

 to general phj'sico-chemical problems, and to those broad questions concerning the 

 relations of the elements which I would venture to group under the head of ' Com- 

 parative Chemistry.' Together these lines of inquiry aftbrd promise of definite in- 

 formation about the real nature of the seventy or more entities we term ' elements,' 

 and about the mechanism of that mysterious yet definite change in matter 

 which we call ' chemical action.' Now and again one or other class of investiga- 

 tion enables us to get some glimpse beyond the known which stimulates the 

 imaginative faculty. 



For example, a curious side-light seems to be thrown on the nature of the 

 elements by the chemico-physical discussion of the connection existing between 

 the constitution of certain organic compounds and the colours they exhibit. 

 Without attempting to intervene in theinterestingcontroversy in which Armstrong 

 jiod Hartley are engaged as to the nature of the connection, we may take it as an 



