THE STUDY OF HYDRO-AROMATIC SUBSTANCES. 125 
necessitates the wandering of a methyl group into an ortho position, and 
several instances of similar reactions have already been recorded. A 
closer investigation of the reaction shows that apparently derivatives 
of 1: 3-xylenol-4 are also formed and at first sight this would appear 
to mean that a methyl group had wandered into a meta position. There 
is, however, another possibility. If one methyl group can wander into 
an ortho position why, under certain conditions, should not both methyl 
groups wander into ortho positions, thus giving rise to a 1: 3-xylenol? 
The reaction is very complicated and not easy to work out, owing 
to the difficulty of separating the mixture of bromoxylenols produced. 
At the present time attention is being particularly directed to the 
synthetic formation of those bromoxylenols which appear likely to be 
produced in the reaction, as very few of these substances are described 
in the literature. 
Composition and Origin of the Crystalline Rocks of Anglesey.— 
Seventh Report of the Committee, consisting of Mr. A. 
Harker (Chairman), Mr. E. Greenty (Secretary), Dr. J. 
Horne, Dr. C. A. Mattey, and Professor K. J. P. Orton. 
In presenting this, their final Report, the Committee desire to sum- 
marise briefly the work that has been done since their appointment. 
Work was begun in the summer of 1905, and has been proceeding ever 
since, but the time that Mr. J. O. Hughes’ duties as demonstrator in 
the University College of North Wales has allowed has never been very 
great, and progress has consequently been slow, the more so as modern 
methods of silicate analysis make very heavy demands upon time. 
Altogether about 80 rocks have been analysed, 12 qualitatively, 68 
quantitatively. Of the quantitative analyses, 43 have been complete, 
the others partial. As a certain number of older analyses are also 
available, it is probably safe to say that the rocks of hardly any other, 
perhaps no other, district of the same size will have received so much 
attention from the chemical point of view as those of Anglesey. 
The Committee also desire to express their very great obligations to 
Mr. Hughes, without whom the work would have been quite impossible. 
Indeed, it is not too much to say that the work of the Committee is the 
work of Mr. Hughes. (That of the, Secretary has been confined to 
selecting the subjects for analysis and collecting the material in the 
field.) Of the analyses enumerated, all but a few have been made by 
him, and all the complete ones are his work. The total number of 
estimations that have been made is about 730, and of these 39 are by 
other hands, so that Mr. Hughes has made for the Committee 691 
estimations. Only those who have had some experience of the analysis 
of rocks, especially of silicates, will be able to appreciate the patient 
care involved in such work, carried on unremittingly through seven 
years. Nor will any but those who have had occasion to deal with 
the baffling problems presented by the crystalline schists be wholly 
able to appreciate the value of Mr. Hughes’ contribution to petrological 
science in general and to our knowledge of the rocks of the British 
islands in particular. 
The thanks of the Committee are also due to the University College 
