150 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[April, 



wlietber placeil at the mouths of the separate glens or at more distant 

 points. He does not, however, propose the alternative that the 

 beaches, if not deposited, hy lakes, must of necessity have been formed by 

 channels of the sea, because he deems it more satisfactory to prove, from 

 independent phenomena, that a sheet of water, gradually subsiding from the 

 height of the upper shelves to the present level of the sea, occupied for long 

 periods, not only the Glens of Lochabar, but the greater number, if not all, 

 the valleys of tliat part of Scotland, and that this water must have been that 

 of the sea. It is argued by the author, that the fluctuating element must 

 have been the land, from the ascertained fact of the land rising in one part, 

 and at the same time sinking in another ; and therefore, that this change of 

 level in Scotland, attested as it is by marine remains being found at con 

 siderable heights both on the eastern and western coasts, implies the elevation 

 of the laud, and not the subsidence of the surrounding waters. The author 

 nest shows that in all prolonged upward movements of this kind, it might 

 bo predicted, both from the analogy of volcanic action and from the occur- 

 rence of lines of escarpment, rising one above the other in certain regions, 

 that, in the action of the subterranean impulses, there would be intervals of 

 rest. On the hypothesis that the land was subjected to these conditions, it 

 appears that its surface would have been modelled in a manner exactly 

 similar, even in its minute details, to the existing structure of the valleys in 

 I/Ochabar. Considering that he has thus established his theory, the author 

 proceeds to remove the objections which might be urged against its truth, 

 derived from the non-extension of the shelves, and the absence of organic 

 remains at great altitudes. He then shows how various details respecting 

 the structure of the Glens of Lochabar, such as the extent of corrosion of 

 the solid rock, the quantity of shingle, the numerous levels at which water 

 must have remained, the forms of the heads of the valley, where the streams 

 divide, and especially their relation with the shelves, and the succession of 

 teiTaces near the mouth of Glen Spean, are all explicable on the supposition 

 that the valleys had become occupied by arms of a sea which had been 

 subject to tides, and which had gradually subsided during the rising of the 

 land; two conditions which could not be fulfilled in any lake. From the 

 attentive consideration bestowed by the author on these several and inde- 

 pendent steps of the argument, he regards the truth of the theory of the 

 marine origin of the parallel roads of Lochabar — a theory of which the 

 foundation-stone may be said to have been laid by the important geological 

 researches of Mr. I^yell, establishing the facts of continents having slowly 

 emerged from beneath the sea — as being sufficiently demonstrated. Tlie 

 author states, in the concluding part of his paper, the following as being the 

 chief points which receive illustration from the examination of the district 

 of Lochabar by Sir Thomas Dick Lauder, Dr. M't'ulloch, and himself. It 

 appears that nearly the whole of the water-worn materials in the valleys of 

 this part of Scotland were left, as they now exist, by the slowly retiring wa- 

 ters of the sea ; and the principal action of the rivers since that period has 

 been to remove such deposits; and, when this had been effected, to excavate 

 a wall-sided gorge in the solid rock. Throughout this entire district, every 

 main, and most of the lesser inequalities of surface are due, primarily, to the 

 elevating forces, and, secondarily, to the modelling power of successive beach- 

 lines. The ordinary alluvial action has been exceedingly insignificant, and 

 even moderately sized streams have worn much less deeply into the solid 

 rock than might have been anticipated, during the vast period which must 

 have elapsed since the sea was on a level with the upper shelves : even the 

 steep slopes of turf over large spaces, and the bare surface of certain rocks, 

 having been perfectly preserved during the same lapse of time. The ele- 

 vation of this part of Scotland, to the amount of at least 1,278 feet, was ex- 

 tremely gradual, and was interrupted by long intervals of rest. It took 

 place either during the so-called " erratic block period," or afterwards; and 

 it is probable that the erratic blocks were transported during the quiet for- 

 mation of the shelves. One of these was found at an altitude of 2,200 feet 

 above the present level of the sea. The most extraordinary fact is, that a 

 large tract of country was elevated to a great height, so equably, that the 

 ancient beach-lines retain the same curvature, or nearly so, which they had 

 when forming the margin of the convex surface of the ancient waters. The 

 inferences drawn by the author from these facts, and which he corroborates 

 by other evidence, are, that a large area must have been upliftid, and that 

 its rise was effected by a slight change in the convex form of the fluid matter 

 on which the crust of the earth rests : and therefore that the fluidity of the 

 former is sufficiently perfect to allow of the atoms moving in obedience to 

 the law of gravitation, and consequently of the operation of that law modi- 

 fied by the centrifugal force : and lastly, that even the disturbing forces do 

 not tend to give to the eai'th a figure widely different from that of a spheroid 

 in equilibrium. 



March 7. — The Marquis of Northampton, President, in the chair. 



George Gulliver, Esq., and George Godwin, junior, Escp, were elected 

 Tellows. 



The following papers were read : — 

 1. Researches in Physical (Jeologtj, Third Series, ' On the Phciwmaiu of fje- 



cession and Nutation, assinnimi 'tha interior of the earth to be a hcterogeneons 

 fluid,' byW.HoPKiNS, Esq. M.A. 



Having, in his last memoir, completed the investigation of the amount 

 of precession and nutation, on the hypothesis of the earth's consisting of a 

 homogeneous fluid mass contained in a homogeneous solid shell, the 

 author here extends the inquiry to the case in which Ijoth the in- 

 terior fluid and external shell are considered as heterogeneous. After 

 givnig the details of his analytical investigation, he remarks that he 

 commenced tho juijuiry ju the cxpectatiou that the solution of this 



problem would lead to results different from those previously obtained, on 

 llio hypothesis of the earth's entire solidity. This expectation was founded 

 on the great difference existing between the direct action of a force on a solid, 

 and that on a fluid mass, in its tendency to produce a rotatory motion ; for, 

 in fact, the disturbing forces of the sun and moon do not tend to produce 

 directly any motion in the interior fluid, in which the rotatory motion causing 

 precession and nutation is produced indirectly by the effect of the same 

 forces on the position of the solid shell. K modification is thus produced in 

 the effects of the centrifugal force, which exactly compensates for the want 

 of any direct effect from the aclion of the disturbing forces; a compensation 

 which the author considers as scarcely less curious than many others already 

 recognized in the solar system, and by which, amidst many conflicting 

 causes, its harmony and permanence are so beautifully and wonderfully 

 preserved. The solution of the problem obtained by the author destroys the 

 force of an argument, which might have been urged against the hypothesis 

 of central fluidity, founded lui the presumed improbability of our being able 

 to account for the phenomena of precession and nutation on this hypothesis, as 

 satisfactorily as on that of internal solidity. The object, however, of physical 

 researches of this kind, is not merely to determine the actual state of the globe, 

 but also to trace its past history, through that succession of ages in which the 

 matter composing it lias probably passed gradually tlirougb all the stages be- 

 ti\eeu a simple elementary state to that in which it has become adapted to the 

 habitation of man. In tliis point of view the author cimceives the problem 

 he i)roposes is not without value, as demonstrating an important fact in the 

 history of the earth, presuming its solidification to have begun at the surface 

 — namely, the permanence of the inclination of its axis of rotation, from the 

 epoch of the first formation of an exterior crust. This permanence has fre- 

 <iuent]y been insisted on, and is highly important as connected with the 

 speculations of the author on the causes of that change of temperature which 

 has probably taken place in the higher latitudes; all previous proofs of this 

 fact having rested on the assunqilion of the earth's entire solidity, an as- 

 sumption which, whatever may be the actual state of our planet, can never 

 be admitted as applicable to it at all past epochs of time, at which it may 

 have been the habitation of animate beings. The author concludes by ex- 

 pressing a hope that he may be enabled to prosecute the inquiry still further, 

 and to bring before the Royal Society, at a future time, the matured results 

 of his speculations. 



2. ' On the Male Orqaiis of some of the Cartilaginous Fishes,' by John 

 Davy, M.D. 



In this paper, which is wholly occupied with anatomical details, the author 

 refers to his paper on the torpedo, which was published in the Philosophical 

 Transactions for 1834; and also to MuUer's work, * De Glandularum Secer- 

 nentium Structura Penitiori,' whose descriptions and views are not in ac- 

 cordance witli those given in that paper. In the present memoir he adduces 

 evidence of the accmacy of his former statements, and offers some con- 

 jectures respecting the functitms of several oi'gans found in cartilaginous 

 fishes, but does not pretend to attach inidue importance to his speculations. 

 March 1 4. — J. \V. Li'Udock, Es(i., V.P. and Treas., in the chair. 



<.;. W. Featberstonhaugh, Esq. was re-elected ; and Clement Tudway 

 Swanstou, Esq. was elected a Fellow. 



The follow ing papers were read ; — 



1. ' An Experimental Inqniri/ into the Fornia/ion of Alkaline and Earthj 

 Bodies, with reference to their Presence in Plants, the influence of Carbonic 

 Acid in their Generation, and the eqnilibrinniofthis Gas in the Atmosphere ^' 

 by Robert Rigg, Esq. Communicated by the Rev. .T. B. Reade. 



The object of the author in the present memoir is to show, that the solid 

 materials which ci^mpose the residual matter in the analysis of vegetable sub- 

 stances, and which consist of alkaline and earthy bodies, are actually formed 

 during the process of fermentation : whetlier tliat process be excited arti- 

 ficially by the addition of a small quantity of yeast to fermentable mixtures, 

 or take place naturally in the course of vegetation, or of spontaneous de- 

 composition. His experiments also tend to show, that this formation of 

 alkaline and earthy bodies is always preceded by the absorption of carbonic 

 acid, whether that acid be naturally formed, or artificially sujiplied. He 

 finds, al«o, that different kinds of garden mould, some being calcareous, 

 others siliceous, and others aluminous, exposed in retorts to atmosjdieres 

 consisting of a mixture of carbonic acid gas and common air, absorbed large 

 quantities of the former, combining with it in such a manner as not to afford 

 any traces of this carbonic acid being disengaged by the action of other acids. 

 He considers the result of this combination to be the formation of an alka- 

 line body, and also of a colotning matter. This combination takes place 

 to a greater extent during the night than during the day ; and in general, 

 the absorption of carbonic acid by the soil is greatest in proportion as it is 

 more abimdantly produced by the processes of vegetation ; and conversely, 

 that it is least at the time when plants decompose tliis gas, appropriating its 

 basis to the purposes of their own .system. Hence, he conceives, that there 

 is established in nature, a remarkable compensating provision, which regu- 

 lates the quantity of carbonic acid in the atmosphere, and renders its pro- 

 portion constant. 



2. ' Note oil the Art of Photor/raphy, or the Application of the Chemical Kays 

 of Light to the Purposes of Pictorial Representation,' by Sir JoiiN F. W. 

 Herschel, Bart. 



The author states, that his attention was first called to the subject of M. 

 Daguerre's concealed photographic processes, by a note from Capt. Beaufort, 

 dated the 22nd of January last, at which time he was ignorant that it had 

 been considered by Mr. Talbot, or by any one in this country. As an 

 enigma to be solved, a variety of processes at once presented themselves, 

 of which the most promising are tho foUoiring :.»i'irst, the so-called de- 



