Mar. 30, 1888.] 



SCIENTIFIC NEVSAS. 



307 



Orthochromatic Photography ; " he considered that the 

 dye on the plate is reduced by the action of light, and 

 subsequently acts as a developer. Mr. Lyonel Clarke, 

 in a paper on " The Metamorphoses of the Silver Image," 

 gave an account of some experiments he had made on 

 reducing and redeveloping silver prints. Mr. W. F. 

 Donkin described a new form of sensitometer, based on 

 the principle of the pin-hole camera. In the last paper 

 Mr. Andrew Pringle explained the " Application of 

 Centrifu£;al Force to Washing Emulsions." 



ROYAL SOCIETY OF EDINBURGH. 

 At the meeting on March 5th Mr. J. Murray communicated 

 the report of Dr. A. Giinther, keeper of the Zoological 

 Department of the British Museum, on the fishes obtained 

 by Mr. John Murray in deep water on the north-west coast 

 of Scotland between April, 1887, and February, 1888, dur- 

 ing which time he was on board the Medusa. The number 

 of species collected in this way, and dealt with in Dr. 

 GUnther's report, was thirty-one — three of which had 

 been found for the first time in British waters. Details 

 were given concerning each of the fish so collected, and 

 as to the localities in which they had been obtained — 

 remarks by the reporter upon each specimen being 

 added. Two communications by Professor Tait were 

 read — one on the mean free path and the number of 

 collisions per particle per second in a group of equal 

 spheres, and a second on the compressibility of glass at 

 different temperatures. Professor Haycraft communi- 

 cated a paper by Dr. E. W. Carlier and himself on the 

 morphological changes which take place in blood during 

 coagulation. The professor explained that the first set 

 of experiments conducted in connection with the research 

 had been in oil, on the lines shown at a former meeting 

 of the Society. The general conclusion arrived at from 

 them had been that glass (the solid substance in this 

 case) acted simply as a mechanical stimulus on white 

 blood corpuscles. The results of the second set of 

 experiments conducted on the same lines, but with the 

 substitution of vaseline for oil, the authors considered as 

 going to prove — notwithstanding the opinion held by 

 some observers that many blood corpuscles break down 

 as soon as the blood is shed — that, in this case, none 

 were visibly breaking down before coagulation occurred. 

 Some had become transparent, but most had retained 

 their vital powers of producing movement. 



GEOLOGICAL SOCIETY. 



At the meeting held on March 14th, 1888, Mr. W. T. 

 Blandford, LL.D., F.R.S., president, in the chair, the fol- 

 lowing communications were read : — 



(i.) "On the Gneissic Rocks off the Lizard." By 

 Howard Fox, Esq., F.G.S., wi'th Notes on Specimens by 

 J. J. H. Teall, Esq., F.G.S. 



The rocks may be classed under three heads :— (i.) the 

 coarse gneisses of Men Hyr type, (ii.) the light-banded 

 granulitic gneisses or Wiltshire type, and (iii.) the tran- 

 sition micaceous rocks of " Labham Reefs," type inter- 

 mediate between (ii.) and the mainland schists. 



The first are seen in Mulvin, Taylor's Rock, Man-of- 

 war rocks, the Stags, Men Par, Clidgas, Men Hyr, and 

 Vasiler; the second in Sanspareil, the Quadrant, and 

 adjoining reefs, Labham Rocks, etc., and the third in the 

 Labham reefs. 



The gneisses and granutites of several of the islands 

 are traversed by numerous dykes of porphyritic basic 



rock, seen in Taylor's Rock, Man-of-war Rocks, Sans- 

 pareil, Quadrant Rock and Shoals, and Clidgas. These 

 dykes have been disturbed by movements subsequent to 

 their intrusion. They sometimes strike across the folia- 

 tion-planes of the gneiss and send veins into the latter 

 rock ; at other times the strike is parallel to that of the 

 foliation-planes. 



The dykes vary in width from 18 inches to several 

 feet. 



In his notes on the specimens Mr. Teall says that the 

 rocks may be arranged in four groups : — 



1, principally occurring in the outer islands, are of the 

 Men Hyr type, consisting of felspar, quartz, dark mica, 

 and hornblende. The rocks possess the mineralogical 

 composition of quartz diorite, and may be termed 

 tonalite-gneisses. 



2, occurring chiefly in the inner islands, are of the 

 nature of granulitic gneisses and granulites, confining 

 the latter term to rocks in which the quartz and felspar 

 are present wholly in the form of a micro-crystalline 

 mosaic of fairly uniform grain. 



3. Rocks showing a passage from the granulitic rocks 

 to the mica-schists of the mainland, as the brown 

 schistose rocks of Labham Reefs. The Enoch rock, a 

 coarse quartzless hornblende schist, also has affinities 

 with the mainland schists. 



4. Dykes traversing the gneisses, consisting of por- 

 phyritic felspars lying in a ground-mass of hornblende 

 and granulitic felspar. The hornblende is probably 

 secondary after augite, and the rocks epidiorites. The 

 period of dynamic metamorphism, of which the most 

 striking results are seen in the schists of the south-wes- 

 tern portion of the Lizard peninsula, was posterior to 

 to the formation of the basic dykes. There is no evi- 

 dence of igneous action in this district since the period ot 

 metamorphism. 



(2.) "TheMonian System." By the Rev. J. F. Blake, 

 M.A., F.G.S. 



The object of the author was to show that the whole 

 of the rocks, which, under various names, had been 

 described as Pre-Cambrian in Anglesey constitute a 

 single well-characterised system, of which the various 

 divisions hitherto described are integral and inseparable 

 parts. 



The evidence of these rocks being Pre-Cambrian was 

 first discussed, and it was shown that the greater part of 

 it went no further than to prove them Pre-Ordovician, 

 the basal conglomerates being associated with rocks of 

 Arenig age, though from the occurrence of these con- 

 glomerates on Holyhead Island it was inferred that the 

 previous denudation had been great. The rocks of the 

 eastern district, however, are proved to be Pre-Cambrian 

 from the basal Cambrian rocks of Bangor type lying on 

 them unconformably near Beaumaris and near Redwharf 

 Bay. The rocks described are found in six distinct 

 districts in Anglesey. 



YORKSHIRE COLLEGE ENGINEERING SOCIETY. 

 Mr. a. H. Meysey-Thompson, on March 12th, read a 

 paper on " Pumping Machinery," before the Society. By 

 means of drawings and photographs the author traced 

 the progress of the steam-pumping engine from Savery's 

 engine (patented 1698, and which still survives in the 

 " Pulsometer " ) to Newcomen's and Watt's engines, 

 which were unable to be worked with a high range ot 

 expansion of steam. From these developed the Cornish 

 engine, and considering that it was a single-cylindei 



