cies are found in every latitude and in every country. For example, such common forms as Achnanthidium lanceolatum, Achnanthes exilis, Gomphonema tenellum, G. constrictum, G. capitatum, Cocconeis Placentula, C. Pediculus, Cocconema lanceolatum, C. cymbiforme, Synedra radians, Navicula elliptica, N. rhomboides, Pinnularia viridis, P. major, P. oblonga, P. borealis, Surirella biseriata, S. ovata, Meridion circulare, M. constrictum, Cymbella maculata, C. scotica, C. cuspidata, Epithemia turgida, Ep. Argus, Himantidium Arcus, H. gracile, H. majus, Odontidium mesodon, Diatoma tenue, D. vulgare, Nitzschia linearis, N. amphioxys, Melosira varians, and many others actually occur in every part of the world from whence these soils have come; and there is absolutely no difference between the exotic and the British forms. Ehrenberg specifies two species, namely, Pinnularia borealis (P. latistriata, W. G.) and Eunolia amphioxys (Nitzschia amphioxys, W. Sm.), as having been found by him in almost every instance. My results confirm this. In no case have both of these been absent, and in at least nine-tenths of these soils both are present. They are often the predominant forms, and in a few cases almost the only forms present. Gomphonema tenellum and Achnanthidium lanceolatum are found in a large majority of these soils. I am disposed to agree in opinion with Ehrenberg, that the microscopic organisms found in soils contribute materially to the increase of the soil. This is true both of the siliceous and calcareous forms. The Diatomacea live in moist earth. They obtain silica from the water, and at their death their shells are added to the soil. Where many are present, this process of transference of silica from the rock to the soil goes on very rapidly. We have so far evidence that they live in these soils, that we find them there very often in the state of self-division, which is not observed in old accumulations of the dead shells. The peculiar capacity of the Diatomacea for resisting climatic changes, whereby the same species can live and thrive as well in the Arctic circle as under the line, corresponds well with the results of the study of the same organisms in the fossil state. In Ehrenberg's 'Mikrogeologie' will be found very fine figures of the Diatoms occurring in the different forms of Bergmehl, Tripoli or polishing slate, Kieselguhr, pumice, and other volcanic rocks, mountain limestone, amber, &c., and it will be seen that by far the greater number of the species are quite identical with recent ones. Microscopic organisms have been found so low down as the green sand of the Silurian system; but they rather belong to the Polythalamia. The earliest Diatoms, geologically speaking, as figured by Ehrenberg, agree in every point, as far as the great majority of the species is concerned, with those now living in our waters, and forming deposits which will become rock at some future time. It was supposed that most of the species in the much more recent Bergmehl were no longer to be found living; but most of them have been since found. I myself have lately found two species of the Lapland Bergmehl to be still in existence, namely, Eunotia octodon and Synedra hemicyclus; and Eunotia incisa, which occurs both in the Lapland and the Mull earths, has been found recent by me in a dozen British gatherings. Yet all these forms were supposed, not long since, to be exclusively fossil. We cannot say that there are no species exclusively fossil, but so many that have been thought so are daily found living, that it is probable the rest may be so found too, and at all events, a very large proportion of the forms in the oldest fossil deposits are absolutely identical with the forms of the present day. I have only further to mention, that although so many species are universal in their habitat, some appear to be local. Thus, Terpsinoë musica does not occur in Europe, nor has it yet been found except in America, and, I think, in Australia. Some species are decidedly Alpine; for example, Orthosira spinosa, which Professor Smith found on the Mont d'Or in Auvergne, and Professor Balfour on the Grampians. It occurs also in nearly every soil from the Andes. 5. On the Injurious Effects of an excess or want of Heat and Light on the Aquarium; by ROBERT WARINGTON, Esq., (Ann. Mag. Nat. Hist., vol. xvi p. 313.)-Temperature is a point requiring great attention in carrying out successfully the principles of a permanent aquarium. The mean temperature of the ocean is estimated to be about 56° Fahr. and this, under ordinary circumstances, does not vary more than about 12° throughout the different seasons of the year. The causes of this equilibrium will be readily understood when we take into consideration the effects that must be produced by the continued flux and reflux of the tides, and by the enormous streams of water which must be flowing from the Arctic regions from year's end to year's end in one constant current, and which, by their movement, must necessarily cause other currents to flow in and take their place, thus forcing, as it were, the heated surface-water of the tropical seas towards the colder regions of the globe. Again, the whole surface of the earth, submersed below the ocean, is protected by this fluid coating from the eflects of the cooling influences of radiation on the one hand, and from contact with the currents of the atmosphere on the other; and hence we perceive an always existent cause for the maintenance of a steady, equable temperature by the waters of the ocean throughout the year. Many of the inhabitants of the sea are very sensitive to changes of temperature, and we find that a few degrees of variation will cause them rapidly to move their position and seek some cooler or warmer spot as the case may be. In the ocean it will be evident that the creatures have the power readily to effect this under ordinary circumstances, by seeking deeper water not liable to be affected by atmospheric influ ences, by partially or entirely burying themselves in the sand or shingle, or by shielding their bodies under the protecting shadow of the rocks or growing vegetation. In arranging the rock-work in the interior of the aquarium, therefore, great care should be taken to keep these points in view, and to afford as much protection as possible to the creatures from the cooling influences of radiation on the one hand, and from the heat of the sun's rays on the other. From my own experience I find that the range of temperature should not be below 50° Fahr., nor above 70°; within these limits all appears to progress healthily, but beyond these points many of the creatures are rapidly affected. During the last long-continued and severe winter, it was found very difficult, in an ordinary sitting-room having a south aspect and a good fire maintained throughout the day--the tanks being also screened at night by a blind,-to prevent the powerful cooling effects from radiation on a clear frosty night; and on three several occasions, marking exactly the three severest frosts that we experienced during the winter, the thermometer immersed in an aquarium containing about thirty gallons of water, fell as low as 45° Fahr. The Shrimp and Crab tribes, and the Crustaceans generally, are especially affected by these changes, and on each of the three occasions alluded to, one or two individuals perished; the larger-sized Prawns, as Palemon serratus, appeared to suffer more readily than the P. squilla, although this might arise from the smaller ones being able to find a shelter from the radiation by concealing themselves more completely among the rock-work or vegetation. Anthea cereus is also very sensitive to considerable variations of temperature, falling from its foot-hold to the bottom of the tank apparently dead. Excess of heat and also strong sunlight are likewise to be as carefully guarded against, and I may state as an evidence of this, that on a particularly hot day during the summer of 1854, being absent from home, the servant omitted to screen a small case from the sun's rays during the hottest period of the day, and on my return I found every creature dead. It contained an Anthea cereus, Actinia dianthus, two specimens of Athanas nitescens, and several others. Too much light has also the effect of rapidly propagating several of the minute animalcules of a green color, as the Euglena and its congeners, which under this influence multiply so rapidly as to render the whole water of a grass-green hue; this will at times subside to the lower part of the tank as evening approaches and disappear in the shingle bottom, but immediately the morning light shines strong upon the aquarium it will rise like a thin green cloud and diffuse itself throughout the whole of the water. Although this animalcular growth is not unhealthy, yet it causes the aquarium to present a very unsightly appearance, and prevents all observation on the habits of the inmates. The want of light, I need hardly observe, causes the rapid decay of the vegetation, and the products arising from this change are highly poisonous to animal life, the whole contents of the aquarium becoming of a black color, and very soon of an offensive odor. IV. ASTRONOMY. 1. Variable Star, (Compt. Rend., 41: 950.)-Mr. Luther at Bilk has discovered a new variable star called T. Piscium. Its variation in magnitude is from 9-10 to 11. Its position for the equinox of 1800 was R. A. Oh 20m 26s and Dec. 13° 26'. 2. New Comets, (Astron. Journ., 90.)-Mr. C. Bruhns at Berlin discovered a comet on the 12th of November, appearing like a feeble nebula. Its position at 17h 22m of that day was R. A. 149° 1′ 26′′, and Dec. +2° 7' 15", with a daily motion in R. A. of about 20′ of arc and in Dec. almost nothing. On the 12th of Dec., William Mitchell of Nantucket reported the discovery, at eight o'clock on the preceding evening, of a telescopic comet in the neck of Cetus. 3. Two New Planets.-M. Chacornac, at Paris, discovered January 12, 1856, a new planet, (38) fainter than a star of the 10th magnitude. On the 8th February, he discovered another planet (39) having a brightness of a star of the 8th or 9th magnitude. In announcing these discoveries to the Academy, M. Leverrier remarked that he was more and more convinced that a large number of small planets exists between Mars and Jupiter, and that before 1860 probably as many as a hundred will have been detected. 4. Elements of Fides (36) or (37), (Astron. Journ., 90.)-These elements were computed by Mr. George Rümker from the observations at Bilk Oct. 6, Berlin Oct. 23, Hamburg Nov. 2 and 13. 5. Elements of Comet 1855, III, (Ibid.,)-Mr. George Rümker has computed the following elements from the observations of Berlin Nov. 12, Bilk Nov. 15, and Hamburg Nov. 20. Perihelion passage Nov. 25, 66041, 1855, M. T. Greenwich. Long. perihelion, 85° 21' 41" Apparent equinox, 52 2 47 10 16 29 V. MISCELLANEOUS INTELLIGence. Nov. 15. 1. Postscript to Prof. Rogers's Paper on Binocular Vision; by the Author. Since the last page of this article was put to press I have seen in an elaborate memoir of Czermak, entitled "Physiologische Studien," the first clear recognition I have met with of the fact that in stereoscope vision there is necessarily an interruption of the usual relation between the axial and refractive adjustments of the eyes. Lest my illustration of this subject, in Part I . . 4 and 5, should be supposed to have been suggested by the remarks of this able observer, I deem it proper to state that this and the other chief points of Parts I and II of my memoir, having been for some time familiar to my thoughts, were communicated to the Warren Club in December, 1854, and to the American Academy, on the 31st of January, 1855. Czermak's memoir forms part of the Sitzungsberichte der K. Ac. der Wissenschaften for March, 1855. This number was issued on the 23d of May following, more than a week after my MS. was in the hands of the printer, and did not reach the Boston Nat. Hist. Soc., where I have just met with it, until the 16th of the present month, nearly eight months after my ideas on this subject were in print. I may add that it has given me much pleasure to find the views of so philosophical an observer coincident in this particular with my own. Boston, Feb. 26, 1856. W. B. R. 2. On a modern Submerged Forest at Fort Lawrence, Nova Scotia ; by J. W. DAWSON, Esq., F.G.S., (Quart. Journ. Geol. Soc., vol. xi, p. 119.) The extraordinary tides of the Bay of Fundy, and its wide marshes and mud-flats, are well known to geologists as affording some of the best modern instances of rapid tidal deposition, and of the preservation of impressions of footsteps, rain-drops and sun-cracks. Attention had not, however, been called to the fact which I propose to notice in this paper, that much, if not the whole, of the marine alluvium of the Bay of Fundy rests on a submerged terrestrial surface, distinct indications of which may be observed in the mud-flats laid bare at low tide, and in the deep ditches dug for drainage. In their natural state, the alluvial soils of the Bay of Fundy are mud-flats overflowed by the high tide, and either quite bare or covered in part with salt-grass. Large tracts have, however, been reclaimed from the sea, and are distinguished by the name of "dyked marsh,” or more shortly "dyke." There are in Nova Scotia 40,000 acres of dyked marsh, and in New Brunswick perhaps 10,000 acres. The soil of the marshes is everywhere a fine marine mud, deposited in thin layers by the tides, and of a brownish-red color; except in the subsoil and in the lower parts of the surface where the color has been changed to gray by the action of sulphuretted hydrogen on the ferruginous coloring matter. Though remarkably productive of grasses and cereals, no part of the marsh-land supports forest trees. Dyked and salt marshes occur in nearly every creek and inlet of the upper part of the Bay of Fundy, more especially in Minas Basin, Cobequid Bay, and Cumberland Basin; and it is in this latter that the submarine forest to which this paper refers is found to underlie the marine alluvium. Fort Lawrence is a low point of upland, resting on Lower Carboniferous rocks, and separating the estuaries of two small streams, the La Planche and Missequash; the latter forming at this place the boundary between Nova Scotia and New Brunswick. Both of these rivers, as well as the other streams emptying themselves into Cumberland Basin, have at their mouths extensive tracts of marsh, and in this instance the marsh-land extends beyond and overlaps the upland point separating the rivers. At the extremity of the point the upland slopes gently down to the dyked marsh, beyond which there is a narrow margin of salt-marsh, scantily clothed with coarse grasses and Salicornia. This margin of marsh without the dyke is overflowed by the highest tides, and may therefore be taken as the high-water level. Owing to the toughness of the upper layer matted with roots, and the action of the neap tides, it presents at the outer edge a perpendicular front about five feet in height. Below this there is a sloping expanse of red mud, cut into many inequalities by the tidal currents, which appear here to be removing the old deposit rather than adding new material. On the surface of this mud I saw impressions of rain-drops and sun-cracks, tracks of sandpipers and crows, and abundance of the shells of Sanguinolaria fusca.* There were also a few long straight furrows, which I was told had been produced by the ice in spring. Owing to the firmness of the mud, they remained (in August) quite sharply marked, though in places filled up with new mud. * Probably identical with Tellina Balthica, Linn. |