292 



SCIENTIFIC NEWS. 



[Sept. 14, li 



occurred. He pointed out that the sides of the vessels in which the 

 experiments were made involved conditions of pressure which 

 did not occur in nature. The scale of the models, too, was untrue, 

 as to represent the actual conditions the model of the Ganges Delta 

 would have to be elongated to 250 feet. He agreed that Dr. 

 Ricketts was discussing an undoubtedly real cause of contortion, 

 but limited its application, and said that the contortion of a schist, 

 Mr. Reid had produced, was on far too small a scale to have been 

 effected on the theory propounded. 



A paper, written by Mr. J. Joly, M.A., B.E., was read, on The 

 Temperature at which Beryl is Decolourised. 



Experiments on some translucent green and yellow beryls from 

 Glencullen, Co. Dublin, show that these beryls are almost entirely 

 deprived of colour when exposed for one hour to a temperature of 

 357 C, i.e., the temperature of boiling mercury at atmospheric 

 pressure. The loss of colour takes place whether the beryls are out 

 of contact with the air or not. It was found further that exposure 

 to a temperature ot 230° C, for the space of thirty hours caused a 

 marked loss of colour. In all cases the crystals retain their trans- 

 lucency. They have shown no signs of regaining colour duriDg a 

 lapse of three years since the date of the experiments. The author 

 suggests that this observation may bear on the history of the con- 

 taining granite subsequent to the formation of beryl, if the colour of 

 the latter be regarded as indicating a major limit to the changes 

 of temperature experienced by the rocks. 



A second paper prepared by Mr. Joly was read, on the Occur- 

 rence of Iolite in the Granite of the County Dublin. 



Mr. W. W. Watts gave an address on Igneous Succession in 

 Shropshire, illustrating his remarks by diagrams. The author de- 

 scribed the succession of igneous rocks in the Shelve and Corndon 

 district of Shropshire. The earliest rocks had a high percentage of 

 silica, and this diminished on each successive phase of- volcanic 

 activity, of which four stages were noted, so that the lightest rocks 

 were erupted first, and densest rocks later. The last part of the 

 paper was taken up with a discussion on the mode of occurrence of 

 these rocks, which had been intruded into spaces formed during the 

 folding and faulting of the strata. 



A brief report was presented from the Committee appointed to 

 investigate the Circulation of Underground Waters in the Permeable 

 Formation of England and Wales, and the Quantity and Character 

 of Water supplied to various Towns and Districts from these Forma- 

 tions. The drought to which the Committee drew atttntion, in its last 

 report, continued up to June of the present year, and had a very 

 marked influence in diminishing the volume of water yielded by a 

 large number of springs, and a very considerable diminution in the 

 supply afforded by the remainder over the greater portion of the 

 central area of England, an area in which underground stores give 

 the larger proportion of the daily water supply of the population. 

 Much useful information had been obtained as to the amount of 

 diminution experienced, but it had been thought desirable to com- 

 bine it with information now being collected, showing the effect of 

 the recent heavy rains in recharging the underground stores. Such 

 statistics as to the most exceptional season of the present century 

 would have a permanent value in future calculations as to the actual 

 yield likely to be obtained from a given area after successive years 

 of minimum rainfall, and this information was deferred until next 

 year. It was hoped local observers would give special attention to 

 diminution and increase in the yield of the springs. 



A list of works was presented, referring to British Mineral and 

 Thermal Waters, the Chairman remarking it was very appropriate 

 such a list should be presented in Bath. 



The Rev. Dr. Irving dealt with the Origin of Graphite in the 

 Archaean Rocks, reviewing the alleged evidence of life on the earth 

 in archaean times. He asked, is archaean graphite of organic 

 origin ? So convincing has the presence of graphite appeared to 

 some minds as evidence of the pre-existence of vegetation that in 

 the report of the Smithsonian Institution (quoted by Dr. Sterry Hunt 

 in his'" Geological Essays "), the presence of graphite, even in aerolites, 

 is said to " tell us in unmistakable language that the bodies came 

 from a region where vegetable life has performed a part not unlike 

 that which it still plays on our globe." It is well known that car- 

 bon does occur on meteorites ; graphite— identical in properties with 

 iron-graphite — was identified by Berthelot in the meteoric mass 

 which fell at Crafhbourne, near Melbourne, in 1861 ; and during last 

 year it was stated in Nature that carbon has been found between 

 the caminal of the great mass of meteoric iron which fell near 

 Cabin Creek, Johnson's County, Arkansas, in March, 1886. Mr. 

 Lockyer's recent experiments on meteorites with the electric spark 

 have given spectroscopic evidence of the presence of carbon in such 

 bodies in some cases. Dr. Sterry Hunt, in his " Chemical and 

 Geological Essays," remarks, " Graphite, which itself encloses 



apotite, is found included alike in quartz, pyroxene, and in calcite, 

 in such a manner as to lead us to conclude that the crystallisa- 

 tion was contemporaneous with that of all these minerals." 

 The alleged necessary phytogenic origin of graphite had, it appeared, 

 no direct evidence to support it beyond the known fact that it 

 occurred occasionally in later formations, as the result of extreme 

 carbonisation of organic matter of vegetable origin. If, therefore, 

 it could be shown that graphite could be produced in any other way 

 in the archaean rocks it was evident that we must cease to urge its 

 presence in these rocks, as evidence of contemporaneous organic 

 life. Let them consider a few demonstrable facts as bearing upon 

 the question. They knew that graphite occurred in segregated 

 minute masses in "grey" or pig iron, and that it exuded from that 

 metal in the process of cooling, to crystallise in the form of 

 hexagonal plates. It was well known and easily demonstrated in the 

 chemical laboratory that carbon could be obtained in the purest 

 form by the reducing action of metals, of the alkalies, and even 

 of magnesium, upon ordinary carbonic acid gas at high temperatures, 

 or by chlorination of hydro-carbons at red heat. They knew that 

 hydro-carbons could be formed, and were formed frequently in the 

 laboratory by direct combination of carbon with elementary hydro- 

 gen, acetylene being formed by direct synthesis of hydrogen with 

 carbon vapour at the temperature of the electric spark discharges. 

 Marsh gas, too, had been produced by the reaction of carbon 

 bisulphide upon hydrogen-sulphide, in contact with heated metals 

 such as copper. More complicated hydro-carbons were produced 

 when certain metals, such as iron united with carbon, and the 

 metallo-carbides thus formed were acted upon by mineral acids. 

 If now, it were to be admitted that the earth had developed out of a 

 portion of the original nebulous mass from which the solar system is 

 derived, it must have passed through such a condition of things that 

 hydro-carbons must have been formed synthetically by such pro- 

 cesses as had been mentioned, perhaps by others which laboratory 

 research had not yet discovered. Given, then, the existence of 

 hydro-carbons in the dense archaean gaseous envelope which en- 

 shrouded the glowing lithosphere of archaean rocks, it could easily 

 be shown that carbon would be deposited from them. During the 

 last two months the author had produced copious deposits of soft, 

 amorphous carbon by the contact-action of heated fragments of pre- 

 viously calcined pumice upon currents of ordinary coal-gas. He hed 

 also observed that the carbon deposited at an incipient red heat had 

 the steel-grey lustre of graphite, and that at higher temperatures, up 

 to the incipient fusion of the hardest Bohemian glass, the carbon de- 

 posited had a more sooty character. From such evidence they were 

 justified in inferring the deposit of graphite in the earliest crystalline 

 rocks, by the dissociation of hydro-carbons through the contact-action 

 of such rocks at high temperatures, as probable. As to animal life, 

 he could only say that any one who, with a fair command of the 

 German language and a moderate acquaintance with protozoan 

 forms, could form a judgment of ihe merits of the eozobn contro- 

 versy from an acquaintance with Mobin's splendid monograph, Der 

 Ban des Eozoon Canadense, must admit that the evidence of the 

 organic origin of that structure was very slender indeed. And in the 

 face of the overwhelming physical evidence against the possibility of 

 life on this globe, as we know it, having appeared in archaean times, 

 the evidence of such mere mineral infillings representing organic 

 forms must be made infinitely stronger than it has yet been made in 

 order to establish a case. 



A brief discussion ensued in general terms, and after the Rev. G. 

 F. Whedborne had read papers on Some Fossils of the Limestones 

 of South Devon and on Some Devonian Crustaceans, the section 

 formally brought its sitting to a close. 



Geological Department. 



W. Whitaker, Esq., presiding. 



Dr. T. Sterry Hunt, F.R.S., read a paper on Mineralogical 

 Evolution, in the course of which he said, Mr. E. A. Ridsdale, 

 who during the present year (1S88) has done good service by pub- 

 lishing a suggestive essa)', called " Notes on Inorganic Evolution," 

 spoke of the production and conservation of more stable 

 species as a gradual " selection of inert forms," and further, 

 as " a survival of the most inert." But as inertness consisted 

 in stability, and in fitness to resist alike Ihe chemical and me hanical 

 agencies which destroyed other species, it was evident that his 

 phraseology is but another statement of the formula of " the survival 

 of the fittest." 



The great principle of the change of the mineral matters which 

 existed in foimer conditions of our planet into other forms more 

 stable, under the altered conditions of later ages, is but an extension 

 to the mineral kingdom of the laws already recognised in astro- 

 nomical and biological development. As was written in 1884, " That 

 a great law presided over the development ot the crystalline rocks 



