monly peaty and mossy, not being absorbed, flows so slowly as barely to keep the surface wet; and also the rocks on the shores of the lakes and mountain tarns, more or less washed and kept wet by the waves breaking on them, or by drifting spray, and likewise the rocks in the beds, or on the sides of streams which, from fluctuations of level, are rarely long under water, and yet seldom perfectly dry. In these latter situations, it may be remarked, the remains of aquatic plants and of infusoria are to be detected in the colouring matter, as well as soot-like granules. The source of the soot-like matter is not so obvious. In a former number of this Journal, that for July 1844, I have given an account of "a carbonaceous deposit or film, on the Lakes of Westmoreland." That deposit was shewn to be of the nature of soot, and was inferred to be derived from the adjoining manufacturing districts, wafted here by the wind, and falling with mist or gentle rain with a lull of wind. The observations which I have since made, have been confirmatory of this inference, and tending to prove that such precipitation of soot is an ordinary, rather than an uncommon or accidental occurrence here, and adequate therefore to the effect supposed. One confirmatory instance may suffice,—it is that of the discolouration of the sheep of the country, especially after exposure for weeks or months on the higher fells. Seen on their mountain pastures, or when driven into the lower meadows in the early spring, their coats are of so dark a hue as to resemble closely those of their fellows fed in the most smoky precincts of our great towns; and, on examination, the colouring matter staining the fleece, is found to be similar to that of the black film of the lakes and tarns; and in brief, essentially soot. What I have described, may seem disparaging to the lake district," the staple" of which has been poetically defined to be "its beauty." This I can hardly admit; contrast conduces to pleasing effects; dark rocks, and bright verdure are not incongruous on the mountain fell, no more than are the black shores and blue waters of the mountain tarns, or the pure white of the new born lamb by the side of its dark mother. The contrast almost surprises, and surprise com monly pleases; moreover, it ought not to pass unobserved, that the discolouring effects described, however prevalent, are not universal, and that they are often intermixed with brighter hues, tints of red, orange, and white, derived from the lichens which spread over the rocks of drier surfaces, and enhance the variety and beauty of the colouring. In another point of view, in relation to the influence of atmosphere, it may be a question, whether the salubrity of air of this district may not be impaired by the cause adverted to. If it be, it is probably in so small a degree, as not to be appreciable. The good to the town or crowded district from which the fuliginous vapours are removed no doubt preponderates greatly over any possible evil to the country. Benefit may even result to the latter, from the precipitation of the matter of these vapours, in their fertilizing effects on the upland pastures. Thus considered may they not be viewed as an example of the equalizing, moderating tendencies, which belong to the economy of nature, in which, when sufficiently scrutinized no real waste of means can be detected, nor loss of substance? LESKETH HOW, AMBLESIDE, Some views respecting the Source of Light, &c. By JAMES NASMYTH, Esq., F.R.A.S. Impressed with the conviction that the progress of science has often been most importantly advanced by the setting forth of hypothetical views as to the nature of those causes which result in great phenomena, I am, for these reasons, induced to hazard and venture forth with some views on the subject of the nature of the solar light, more especially in reference to the well known but most remarkable phenomena occurring in the case of stars of variable and transitory brightness, as also in reference to those wonderful results of geological research, namely, the unquestionable evidence of the existence of an arctic or glacial climate in regions where such cannot now naturally exist; thus giving evidence of the existence of a condition of climate, VOL. LII. NO. CIII.-JANUARY 1852. E for the explanation of which we look in vain to any at present known cause. I must plead the fact of the existence of such wonderful phenomena as those alluded to, as my apology for thus attempting to come forth with what, although they may appear crude, theoretical notions, yet may, as tending to direct increased attention to important phenomena, so lead in due time to the development of truth, and extend the present bounds of our knowledge to those mighty laws which are so mysteriously indicated by the existence of the phenomena in question, and with the evidences of which we are yet surrounded. A course of observations on the solar spots and on the remarkable features which from time to time appear on the sun's surface, which I have examined with considerable assiduity for several years, had in the first place led me to entertain the following conclusion, namely, that whatever be the nature of solar light, its main source appears to result from an action induced on the exterior surface of the solar sphere, a conclusion in which I doubt not all who have attentively pursued observations on the structure of the sun's surface, will agree. Impressed with the correctness of this conclusion, I was led to consider whether we might not reasonably consider the true source of the latent element of light to reside, not in the solar orb, but in space itself; and that the grand function and duty of the sun was to act as an agent for the bringing forth into vivid existence its due portion of the illuminating or luciferous element, which element I suppose to be diffused throughout the boundless regions of space, and which, in that case, must be perfectly exhaustless. Assuming, therefore, that the sun's light is the result of some peculiar action by which it brings forth into visible existence the element of light, which I conceive to be latent in, and diffused throughout, space, we have but to imagine the existence of a very probable condition, namely, the unequal diffusion of this light-yielding element, to catch a glimpse of a reason why our sun may, in common with his solar brotherhood, in some portions of his vast stellar orbit, have passed, and may yet have to pass, through regions of space in which the light-yielding element may either abound or be deficient, and so cause him to beam forth with increased splendour, or fade in brilliancy, just in proportion to the richness or poverty of this supposed light-yielding element as may occur in those regions of space through which our sun, in common with every stellar orb, has passed, is now passing, or is destined to pass, in following up their mighty orbits. Once admit that this light-yielding element resides in space, and that it is not equally diffused, we may then catch a glimpse of the cause of the variable and transitory brightness of stars, and more especially of those which have been known to beam forth with such extraordinary splendour, and have again so mysteriously faded away; many instances of which abound in historical record. Finally, in reference to such a state of change having come over our sun, as indicated by the existence of a glacial period as is now placed beyond doubt by geological research, it appears to me no very wild stretch of analogy to suppose, that in such former periods of the earth's history, our sun may have passed through portions of his stellar orbit in which the light-yielding element was deficient, and in which case his brilliancy would have suffered the while, and an arctic climate in consequence spread from the poles towards the equator, and leave the record of such a condition in glacial handwriting on the everlasting walls of our mountain ravines, of which there is such abundant and unquestionable evidence. As before said, it is the existence of such facts as we have in stars of transitory brightness, and the abovenamed evidence of an arctic climate existing in what are now genial climates, that renders some adequate cause to be looked for. I have accordingly hazarded the preceding remarks as suggestive of a cause, in the hope that the subject may receive that attention which its deep interest entitles it to obtain. This view of the source of light, as respects the existence of the luciferous element throughout space, accords with the Mosaic account of creation, in so far as that light is described as having been created in the first instance before the sun was called forth. Report on the Investigation of British Marine Zoology by means of the Dredge. Part I. The Infra-littoral Distribution of Marine Invertebrata on the Southern, Western, and Northern Coasts of Great Britain. By Professor EDWARD FORBES. (Continued from page 391 of Vol. LI. of Philosophical Journal.) Gregarious and prolific species.-Many of our littoral mollusca, as the shore-living species of Littorina, Purpura, Trochus, Cardium, Donax, Mya, Pholas, &c., are truly gregarious, and the individuals of each are constantly found assembled together in considerable numbers. This is not so commonly the habit among sub-littoral species; among them, however, there are some habitually gregarious (as Ostrea edulis, &c., and among radiata, Ophiura rosula, Uraster rubens, Comatula europea, Echenus sphæra), though with this difference as compared with the most littoral gregarious forms, that whereas the individuals of the latter are always assembled together, the sub-littoral species are gregarious in some zones of depth and under certain conditions of sea-bottom, while they are at the same time diffused in small numbers, or even as solitary individuals in situations where the conditions do not seem so favourable to fecundity. Many species also, not at all gregarious in the true sense of the word, having a very wide range in depth, are not equally prolific throughout that range, but are developed in much greater numbers in one region than in another, or in different parts of the same region, according to the conditions of the sea-bed. Climatal differences also have a considerable effect in determining the prolific or non-prolific character of a species, and this may be observed clearly, even in such a limited area as that under review. Hence, when we state of many species that they are diffused throughout all the provinces of that area, it is not to be understood that they are equally abundant, so far as their individuals are concerned, in all. Thus, for example, Dentalium entalis is distributed throughout the British seas; but whilst it is so abundant as to be almost gregarious in the northern provinces, it becomes scarce and solitary in the southern. Many examples of this may be seen by consulting the analysis of dredging papers in the preceding tables, and afterwards comparing them with the tables of enumeration of localities of species. In the Littoral region, as mentioned already, the species of Littorina, Trochus, Patella, and Purpura are most abundant, and among bivalves, Mytilus edulis, Cardium edule, and Kellia rubra. These with many other animals, and with peculiar marine plants, give a character to the sea-belt between the tide-mark. |