50 



NATURE 



[Nov. i6, 1871 



The annual general meeting of the Royal Horticultural Society 

 of Ireland was held in Dublin on the 9th of November. The 

 report of the Council was most satisfactory, and the treasurer's 

 account showed a balance on the year to the credit of the society 

 of upwards of 1,060/. Of this sum 1,000/. was added to the 

 reserve fund . In addition to the usual early Spring, Summer, and 

 Autumn shows it was resolved to hold in October next a grand 

 internation.al fruit show, which we hope will be attended with 

 success. 



Mr. John Ruskin has lately presented a valuable collection 

 of minerals and fossils to the High School, Nottingham. Among 

 the former are two hundred metalliferous ores, including some 

 rare specimens from Hungary, a hundred choice silicates, the 

 principal varieties of fluor spar, calcite, and barytes, some 

 agates, and a series of fine gems. The fossils are mainly from 

 the Cretaceous Rocks of Kent and Sussex. 



On Saturday last Sir William Stirling Maxwell was elected 

 Rector of the University of Edinburgh. 



The great Aquarium at the Crystal Palace, of which we re- 

 cently gave a full description and drawing, was formally opened 

 to tlie public on Friday evening last by a soiree. 



The Se=sion of the Institution of Civil Engineers commenced 

 on the 14th inst., and the annual general meeting "to receive and 

 deliberate upon the report of the Council on the state of the In- 

 stitution, and to elect tlie officers for the ensuing year," will be 

 held on Tuesday, the 19th of December. At the same time 

 the members have been reminded of the obligation entered into 

 on election to promote the public and scientific obligations con- 

 templated in the Royal Charter of Incorporation gi-anted to the in- 

 stitution by preparing, or aiding in the preparation of, original 

 communications for reading at the meetings, by frequent attend- 

 ance at the meetings and occasionally talving part in the dis- 

 cussion, and by presenting to the library copies of reports and 

 scientific treatises not already in the collection. It has also been 

 notified that the qualifications of candidates seeking admission 

 into the institution must in all cases be set forth with the utmost 

 precision and in considerable detail, in order to enable the 

 Council, upon whom the classification involves, and the members, 

 with whom the subsequent election rests, to form a correct opinion 

 as to the nature of tlie practice, the extent of the experience, and 

 the degree of responsibility ot every candidate. The casualties 

 which have occurred among the members of this body during the 

 last three months include tlie death of Field-Marshal .Sir John 

 Burgoyne, G. C.B., &c., honorary member; of Messrs. Joseph 

 Hamilton Beattie, John George Blackbume, Robert Benson 

 Dockray, Albinus Martin, and Josiah Parkes, members : and of 

 Messrs. Arthur Field, Edward Mosely Perkins, and Henry 

 Beadon Rotton, associates. This has reduced the total number 

 of members of all classes from 2,009, ^t which it stood on the 

 1st of August last, to 2,000, comprising 14 honorary members, 

 725 members, 1,056 associates, and 205 students. During the 

 period referred to the ordinary general meetings have been 

 suspended, so that there has been no ballot for new members. 



Mk. Brothers has made a photograph eight inches in 

 diameter of one of Mr. Proctor's star maps, containing nearly 

 fifty thousand stars. The more marked constellations are just 

 distinguishable upon a background, which appears to be shaded 

 with innumerable minute points representing smaller stars. Tlie 

 increase of intensity in the shading is very evident upon certain 

 parts of the picture. The whole represents the heavens as we 

 should see them if the pupils of our eyes were a little more than 

 two inches in diameter. 



Dr. J. B. Pettigrew, F.R.S., will deliver a course of 

 twelve lectures on physiological and pathological subjects at the 

 Royal College of Surgeons, Edinburgh. 



THE GEOGNOSY OF THE APPALACHIANS 

 AND THE ORIGIN OF CRYSTALLINE 

 ROCKS* 



III. 



'T^HE direct formation of the crystalline schists from an aqueous 

 magma is a notion which belongs to an early period in 

 geological theory. De la Beche, in 1834,+ conceived that they 

 were thrown down as chemical deposits from the waters of the 

 heated ocean, after its reaction on tlie crust of the cooling globe, 

 and before tlie appearance of organic life. This view was re- 

 vived by Daubree in i860. Having sought to explain the 

 alteration of paln?ozoic strata of mechanical origin, by the 

 action of heated waters, he proceeds to discuss the origin of the 

 still more ancient crystalline schists. The first precipitated 

 waters, according to him, acting on the anhydrous silicates of 

 the earth's crust, at a very elevated temperature, and at a great 

 pressure, whicli he estimated at two hundred and fifty atmo- 

 spheres, formed a magma, from which, as it cooled, were succes- 

 sively deposited the various strata of the crystalline schists.J This 

 hypothesis, violating, as it does, all the notions which sound 

 theory teaches with regard to the chemistry of a cooling globe, • 

 has, moreover, to encounter grave geognostical difficulties. Tlie 

 pre-Silurian crystalline rocks belong to two or more distinct 

 systems of different ages, succeeding each other in discordant 

 stratification. The whole history of tliese rocks, moreover, 

 shows that their various alternating strata were deposited, not as 

 precipitates from a seething solution, but under conditions of 

 sedimentation very like those of more recent times. In the 

 oldest known of them, the Laurentian system, great limestone 

 formations are interstratified with gneisses, quartzites, and even 

 with conglomerates. All analogy, moreover, leads us to conclude 

 that even at this early period life existed at the surface of the 

 planet. Great accumulations of iron-oxyd, beds of metallic 

 sulphids, and of graphite, exist in these oldest strata, and we 

 know of no other agency than that of organic matter capable of 

 generating these products. 



Bischof had already arrived at the conclusion, which in the 

 present state of our knowledge seems inevitable, that "all the 

 carbon yet known to occur in a free state can only be regarded 

 as a product of the decomposition of carbonic acid, and as de- 

 rived from the vegetable kingdom." He further adds, "living 

 plants decompose carbonic acid ; dead organic matters decom- 

 pose sulphates, so that, like carbon, sulphur appears to owe its 

 e.xistence in a free state to the organic kingdom. "§ As a decom- 

 position (deoxidation) of sulphates is necessary to the production 

 of metallic sulphids, the presence of the latter, not less than that 

 of free sulphur and free carbon, depends on organic bodies ; 

 the part "which these play in reducing and rendering soluble the 

 peroxyd of iron, and in the production of iron ores, is, moreover, 

 well known. It was, therefore, that, after a careful study of 

 these ancient rocks, I declared in May, 1S5S, that a great mass 

 of evidence "points to the existence of organic life, even during 

 the Laurentian or so-called azoic period. '"|| 



This prediction w.-is soon verified in the discovery of the Eo- 

 zoijn Canadense of Dawson, the organic character of which is 

 now- admitted by all zoologists and geologists of authority. But 

 with this discovery appeared another fact, which afforded a signal 

 verification of my theory as to the origin and mode of deposition 

 of serpentine and pyroxene. The microscopic and chemical re- 

 searches of Danson and myself showed that the calcareous skel- 

 eton of this foraminiferal organism ^^•as filled «ith the one or the 

 other of these; silicates in such a manner as to make it evident 

 that they had replaced the sarcode of the animal, precisely as 

 glauconite and similar silicates have, from the Silurian times to 

 the present, filled and injected more recent foraminiferal skeletons. 

 I recalled, in connection with this discovery, the observations of 

 Ehrenberg, Mantell, and Bailey, and the more recent ones of 

 Pourtales, to the effect that glauconite or some similar substance 

 occasionally fills the spines of Echini, the cavities of corals and 

 millepores, the canals in the shells of Balanus, and even forms 

 casts of the holes made by burrowing sponges (Clionia) and 



* Address of Prof. T. Sterry Hunt on retiring from the ofBce of President 

 of the American Association for the Advancement of Science : abridged 

 from the " American Naturalist," concluded from p. 34. 



t Researches in Theoretical Geology, pp. 297-300. 



I Etudes et experiences synthfetiques sur le Metamorphisme, pp. 119-121. 

 § Biscliof, Lehrbuch, ist ed. II. 95. English ed. I. 252, 344. 



II Amer. Jour. Science, II. xxv. 436. 



