OcTOCliK i, It, 08 J 



NA TURE 



591 



elcctro-analylical separation of metals with the apparatus 

 described in tlie Journal of the Chemical Society. A some- 

 what similar apparatus was briefly described by Dr. F. M. 

 Perkin. 



Interesting- results obtained with transparent silver and 

 other thin metallic films were shown by Prof. T. Turner. 

 Thin gold leaf becomes transparent when heated to about 

 550° ; the change does not depend on the nature of the 

 atmosphere. Thin silver leaf requires the presence of air 

 or oxygen for a similar change. Thin sheet copper, heated 

 to 200°, becomes transparent, and transmits yellow-green 

 light quite freely. 



A discussion on the practical utilisation of peat was 

 opened by a paper from Dr. Woltereck, dealing with the 

 production of ammonia from atmospheric nitrogen by 

 means of peat. Experiments have shown that a mixture 

 of nitrogen and hydrogen passed over reduced iron at a 

 low heat produces ammonia, and that the presence of 

 oxygen and water was of importance. Finally, the 

 hydrogen was omitted and peat substituted for the iron 

 with satisfactory results. It is claimed that atmospheric 

 nitrogen cooperates in the formation of ammonia. Sub- 

 sequent speakers included Prof. Ryan, Prof. Turner, Sir 

 James Dewar, and Mr. K. B. Eller, but the discussion 

 ■failed to bring out any new facts of importance. 



The aromatic nitroamine committee (secretary. Dr. 

 K. J. P. Orton) reported on the transformation of nitro- 

 amino-benzenes into nitro-anilines. The influence of the 

 solvent, nature of the acid catalyst, and the effect of 

 concentration of the acid and temperature have been 

 studied. 



The report of the committee for the study of hydro- 

 aromatic substances (secretary, Prof. A. VV. Crossley) con- 

 tained the usual valuable summary of recent work in this 

 field, together with new investigations on dimethyldihydro- 

 benzene. 



T^ 



GEOLOGY .4T TH£ BRITISH 

 ASSOCIATION. 



'HE geologists who were privileged to attend the meet- 

 ings of Section C at Dublin will always recall with 

 pleasure the kindly welcome and helpful assistance extended 

 to them by the home geologists. .Not only did they give 

 us a president whose brilliant address promises to be 

 historic, and arrange for our benefit a delightful series of 

 excursions in the neighbourhood of Dublin, but they com- 

 municated many papers of great interest, and took a very 

 active part in the work of the section. 



Prof. Cole's lecture on the geology of the country round 

 Dublin, which followed the president's address, sum- 

 marised the principal points of interest in the district, 

 and led us to a clearer view of the many important features 

 we were enabled to see in the afternoon excursions organ- 

 ised and led by Mr. H. J. Seymour and others. 



Prof. Cole also contributed two other papers, one dealing 

 with the examination of the stones brought up during the 

 dredging expeditions of the Fisheries Branch of the Depart- 

 ment of Agriculture and Technical Instruction for Ireland. 

 The discovery, off the coast of Kerry, of abundant flints, 

 chalk, glauconitic chalk, and Milioline limestone showed 

 that the Cretaceous and Eocene seas extended to an un- 

 known distance towards the west. 



The other paper was explanatory of an exhibit of the 

 types of rock formed during the intervals between the 

 basaltic eruptions in the north of Ireland in Eocene times. 

 It was urged that the red lateritic zone represents basalt 

 altered in situ, and is clearly connected with the climatic 

 conditions of Eocene times. The pale bauxites are con- 

 sidered to be derived from sporadic eruptions of rhyolite, 

 and a thin bauxite layer overlying the pisolitic iron-ore 

 mav in part be formed bv wind-borne material. 



Messrs. K. J. Ussher' H. J. Seymour, E. T. Newton, 

 and R. F. Scharff gave the results of their joint work in 

 the exploration of the Cave of Castlepook, near Doneraile. 

 Both the geological evidence and the characteristics of 

 the fauna collected lead towards the conclusion that the 

 cave is pre-Glacial in age, and support the opinion that 



XO. 2032, VOL. 78] 



Ireland has not been joined to England by land in Glacial 

 or post-Glacial times. 



Messrs. H. B. Muff and R. Carruthers described the 

 structure of the Leenane district, co. Galway, and Prof. 

 S. H. Reynolds and Mr. C. I. Gardiner dealt with rocks 

 along the same strike in the Tourmakeady district, co. 

 Mayo. 



The veteran geologist Mr. G. H. Kinahan, although 

 prevented from attending the meeting through illness, 

 sent a paper on the raised beaches of the Lift'ey Valley, 

 and Mr. H. Bolton reported the details of a boring in 

 the Lower Coal-measures at the Emerald Pit, Dun- 

 gannon. 



The igneous rocks of the seldom visited outer Blasket 

 Islands were described by the president. 



Besides the above papers dealing with Irish geology, a 

 fine collection of photographs of geological interest, and 

 a typical set of Irish rocks, were exhibited by Mr. R. 

 Welch and other local workers. 



Desert phenomena, which have played so important a 

 part in the proceedings of the section for some years 

 past, were again discussed in several important papers. 

 Dr. W. F. Hume contributed notes on the petrography of 

 Egypt, Mr. G. \V. Grabham dealt with the well-water 

 supply of the north-east Sudan, Dr. A. Hutchinson gave the 

 results of a chemical and physical examination of some 

 remarkable crystals of dolomite obtained from Algeria, 

 while fossil deserts were referred to in the report of the 

 Trias Committee, ^^'ith the view of obtaining further data 

 regarding the conditions under which the Triassic rocks 

 of Britain were laid down, a new research committee was 

 appointed to conduct investigations in the marginal parts 

 of the Sahara about Biskra, in Algeria, and Mr. J. Lomas 

 will shortly proceed to .Africa to make observations bearmg 

 on the point. 



In glacial geology two papers were presented. Dr. 

 Dwerryhouse, in reading the report of the Erratic Blocks 

 Committee, showed that there is still much useful work to 

 be done, despite the long time the committee has been at 

 work. Prof. \V. M. Davis, of Harvard University, in 

 dealing with the glacial erosion in north Wales, confined 

 his remarks to the Snowdonian district. He demonstrated 

 that in Tertiary time the mountains existed as a group of 

 monadnocks surmounting a peneplain which extended far 

 into mid-Wales. During the Glacial epoch the intervening 

 valleys were deepened, and cwms were formed which 

 showed that glacial erosion in certain valleys amounted 

 to 400, 600, or 800 feet. 



In mineralogy and petrography eight important papers 

 were read. The president, in the course of an examination 

 of the Deccan basalt, found them to contain native iron and 

 gold. Dr. A. Hutchinson described a new method of 

 drawing stereographic projections of crystals, and exhibited 

 a protractor designed for the use of students of crystallo- 

 graphv. Dr. H. A. Bemrose showed and described a 

 number of slides illustrating the microstructure of Derby- 

 shire limestones, and Mr. H. Brodrick contributed a note 

 on the structure and occurrence of cave pearls. Dr. 

 Tempest Anderson's paper on the changes in the 

 Soufri^re of St. Vincent was a continuation of the work 

 done by Dr. Flett and himself on the remarkable volcanic 

 eruptions which occurred in the West Indies a few year' 

 ago. 



Dr. J. Milne, in discoursing on the duration and direc- 

 tion of large earthquakes, showed that while small earth- 

 quakes have a duration of a few seconds near their 

 origin, and at a distance of fifty to 100 miles they may 

 not be recordable, large earthquakes suffer no appreciable 

 decay during transmission, and their duration appears to 

 increase rather than decrease, .\nother observation in con- 

 nection with recent seismological observations is that large 

 earthquakes travel farthest in particular directions. 



Other papers on earth movements were contributed by 

 Prof. W. H. Hobbs and Dr. Woolacott. The former dealt 

 with the recent earth movements within the basin of the 

 Laurentian lakes, and by methods of precise levelling he 

 was able to demonstrate that the recent tilting of 

 the province proceeded at vari.able rates at different 

 points. 



Dr. Woolacott, in describing a case of thrust and crush 



