of the leading points in his system, and must bring our exposition to a close.

It will be remembered that sensitive perception (taking the expression in its widest sense) apprehends three things-first, (in sensation) the affections of our animated organism-secondly, (in the perception of our organism as material) the relations of mutual outness which these bear to one another-and thirdly, (in the perception of extra-organic objects, not revealed to consciousness as material) resistance offered to the movement of our organism in space. We have here the basis of Sir W. Hamilton's division of the qualities of bodies. Sensation reveals to us the secondaries. The perception of the organism as material, discovers to us the primaries. And the perception of extraorganic resistance makes us acquainted with the secundo-primaries. To begin with the primaries. In being conscious of the relations of our organism to itself in space, we apprehend it as an object not indivisible and unextended like the ego, but such that affections exist in it, mutually external to one another an object which is also finite, and which may hence be defined as "occupying space and contained in space." This is the definition of matter or body; and whatever properties can be evolved out of this definition, are primary qualities of matter. Thus, figure is a primary quality, because whatever occupies space and is contained in space, must possess figure. It is apparent that the primaries are only in an improper sense termed qualities (or suchnesses); for a body is not, by possessing them, constituted such a body. They do not discriminate one body from another, but belong to all bodies alike. Turn next to the secondaries. In being conscious of organic affections, we apprehend them as differing in kind or quality strictly so called. For example, one affection of the animated organism, apprehended by consciousness, gives the sensation of redness; another, the sensation of acidity -two sensations of a different kind or quality altogether. Now organic affections may be stimulated by causes either within or without the organism. To causes of the former description our attention is seldom powerfully called; but it is necessary on many accounts that the latter sort should be discriminated among themselves, and should receive distinctive names. Accordingly, when we have been led by experience to attribute a particular affection to the stimulating influence of some external body, we ascribe to that body a quality commonly denoted by the same name with the sensation produced in us. Such qualities, collected into a class, form the secondary quali

ties of bodies. Thus we say that vinegar possesses the secondary quality of acidity, and a rose that of redness, because we suppose that the stimuli which originated the organic affections, in apprehending which we felt the sensations of acidity and of redness, proceeded from the vinegar and the rose respectively. We are entirely ignorant what the secondary qualities in bodies are; we only know the affections of which they are deemed to be the stimulating causes.-As the secondaries are revealed through sensation, and the primaries through the perception of our material organism, so the secundoprimaries are discovered (we said) by the resistance offered to the movement of our organism in space. We are not conscious of this resistance as proceeding from bodies; but after we have been led by induction to believe that it is exerted by bodies, we then reckon resistance to be a quality of bodies. But is it a primary or a secondary quality? It partakes in some sort of the nature of both. As a mode of resistance felt in us, it is allied to the secondaries. As a degree of resistance opposing our locomotive energy, it resembles the primaries, being like them objectively apprehended. It cannot therefore be placed under either of the two previous divisions; but must be constituted into a class by itself, viz: the class of secundo-primaries. Every particular species of resistance or pressure which a body is capable of exerting, against the movement of our organism, or against any other body, is a secundo-primary quality of the body in question.

G. P. Y.

SCIENTIFIC AND LITERARY NOTES.

GEOLOGY AND MINERALOGY.

EARTHQUAKES IN CALIFORNIA.

In a paper by Dr. Trask, of San Francisco, published in the May number of Silliman's Journal, it is stated that the number of earthquakes experienced in California in 1856, amounted to sixteen. The shocks, with one exception, appear to have been comparatively slight; and Dr. Trask (writing from San Francisco) observes moreover, that along the coast of Mexico and Central America, to the south of California, there seems to have been a much greater exemption from these phenomena than has been usual in former years. This appears to have been the fact also, throughout the Pacific, Oceanic, and most of the continental islands along the coast of China; while, on the contrary, to the north and northwest, beyond the fifty-fifth parallel, both volcanic and earthquake phenomena appear to have been of more than average intensity. Dr. Trask cites more especially, the neighbour, hood of the Aleutian Archipelago, the north-east coast of Japan, the British and Russian possessions of North America on the Pacific, and the islands of the Sea

of Ochotsk. A submarine eruption in the Straits of Ourinack (lat. 54° 36′ N., longitude 135′ W.) is reported by Captain Newell, of the "Alice Frazer.". A column of water was projected upwards to a height of several hundred feet, and immediately following this, immense masses of lava were thrown into the air whilst the sea for miles around, and for many days after, was covered with floating fragments of pumice. The principal earthquake experienced in San Francisco itself, during the year 1856, occurred on the 15th February, at about half past five in the morning. Several buildings were injured; and the shock appears to have extended over an area of about one hundred and forty-three miles in length, by sixty-six in breadth.

ROCK METAMORPHISM.

Professor T. Sterry Hunt, of the Geological Survey of Canada, has lately made known a very interesting illustration of metamorphic phenomena arising from the action of alkaline silicates on carbonate of magnesia or of iron, or earthy carbonates generally. His experiments shew that when a mixture of silica and carbonate of magnesia is boiled with carbonate of soda, the silicate of soda, at first formed, is decomposed by the magnesian carbonate; and secondly, that the regenerated -carbonate of soda is enabled to take up a new portion of silica: the result being a continued silification of the magnesia through the agency of the alkaline carbonate. Mr. Hunt finds that, if pulverized quartz be boiled for several hours with corbonate of soda and carbonate of magnesia, a large amount of magnesian silicate is formed; and that, if we suppose a solution of alkaline silicate (which will never be wanting among sediments in which feldspar exists) to be diffused through a mixture of siliceous matter and earthy carbonate, we shall have, with a temperature of 112 Faht. or perhaps with less, all the conditions necessary for the conversion of the sedimentary mass into pyroxenite, diallage, serpentine, tale, rhodonite, &c., all of which constitute beds in our metamorphic strata. If, also, aluminous matter be added to the above, the elements of chlorite, garnet and epidote will be present.

WATERS OF THE ST. LAWRENCE AND OTTAWA.,

Professor Hunt has also communicated to the Philosophical Magazine for April, 1857, analyses of the waters of the St. Lawrence and Ottawa rivers, accompanied by some interesting observations, the concluding portion of which we give below. The subject will be found more fully discussed in the Report of the Geological Survey for 1854, now on the eve of publication.

"The comparison of the two river-waters whose analysis we have just given, shews the following differences:-The water of the Ottawa, containing little more than one-third as much solid matter as the St. Lawrence, is impregnated with a much larger proportion of organic matter derived from vegetable decomposition, and a larger amount of alkalies uncombined with chlorine or sulphuric acid. Of the alkalies in the state of chlorides, the potassium salt in the Ottawa constitutes 32 per cent,, and in the St. Lawrence only 15 per cent.; while in the former the silica equals 34, and in the latter 23 per cent. of the ignited residue. The Ottawa drains a region of crystaline rocks, and the alkalies liberated by the decomposition of the feldspar of these rocks give their character to its waters; the extensive vegetable decomposition evidenced by the organic matters in solution, must also contribute a portion of potash; while the basins of the great lakes through which the St. Lawrence flows are excavated in paleozoic strata which abound in limestone, rich in salt and gypsum, and have given to the water of this river that predominance of soda, sulphuric acid and chlorine, which distinguishes it from the Ottawa. The presence of large amounts of silica in river-waters is a fact but recently established. Until the analysis by Deville of the rivers of France (1848), the silica in water had generally been wholly or in great part overlooked; and, as he suggests, had, from the mode of analysis been confounded with gypsum. The importance in an agricultural point of view of this large amount of dissolved silica, where river-waters are employed for the irrigation of land, is very great; and geologically, the fact is not less significant, as it marks a decomposition of the siliceous rocks by the action of waters holding in solution carbonic acid, and the organic acids arising from the decay of vegetable matter, which, dissolving the lime, alkalies, and magnesia, from the native silicates, liberate the silicic acid in a soluble form.* Silica is never wanting in natural waters, whether neutral or alkaline, altnough proportionably less abundant in neutral waters which contain large amounts of earthy ingredients. The alumina, whose presence is not less constant, although in much smaller quantity, appears equally to belong to the soluble constituents of the waters. The amount of dissolved silica annually carried to the sea by the rivers must be very great; yet sea-water, according to Forchhammer, does not contain any considerable quantity in solution; it doubtless goes to form the

* Although this may be true enough to a certain extent, yet, undoubtedly, a large portion of the silica present in the waters of rivers, more especially of such as flow through uncleared districts, is derived from the constant decomposition of the wood of fallen trees, of ferns and other vegetable matters. In the ashes of most ferns, the silica is over 70 per cent., and in those of equiseti, over 50; whilst it averages about 10 or 12 per cent, in the ashes of the bark, wood, and leaves (taken together) of our common pines. E. J. C.

shields of Infusoria, and may play an important part in the consolidation of the ocean sediments and the silification of organic remains."*

AZOIC ROCKS OF CANADA.

Professor Whitney in an article in the May number of Silliman's Journal, takes exception to Sir William Logan's subdivisions of our Azoic rocks. He contends that the so-called Huronian Formation belongs in part to the Potsdam sandstone, and in part to the underlying Laurentian group; aud, further, that the latter should simply be called " Azoic," to the exclusion of the term "Laurentian"this term having been already bestowed by Desor on the local, post-tertiary beds of Beauport, and other places, in the valley of the St. Lawrence and elsewhere. Without attempting, in the present place, to discuss the claims of the Huronian rocks to be considered a distinct formation, we may reasonably call in question the justness of that view, which, by collecting all of our unfossiliferous strata into a single group, would represent them as the products of a single epoch or period. Surely, if the Paleozoic age be looked upon as typical of at least four periods in the history of the Earth, a subdivision of some kind may be equally conceded to the formations of the great Azoic age: although from the absence of fossils, the snbdivision of these formations may be a work of more difficult attainment. That such will some day be effected however, and to a greater extent than many geologists may at present be willing to allow, we are fully confident. With regard to the term Laurentian as applied to some of these Canadian rocks, we would observe, that, even if the same term were previously applied to the patches of post-tertiary strata alluded to above, its peculiar fitness for the gneissoid rocks of the Laurentian Range and connected country, would fully warrant its retention. On the other hand, we quite agree with Professor Whitney respecting the use of the term "Cambrian." If this term cannot be applied in accordance with the views of Sedgwick to the whole of the lower Silurians (a conclusion becoming more and more apparent every day,) let it be abandoned altogether. Its application to the Huronian formation, or to the Potsdam sandstone as proposed by Sir Charles Lyell, answers no object whatever, and is but little likely, moreover, to be generally adopted.

SUPPOSED EMERALDS FROM ALGIERS.

The pale green crystals from the Upper Valley of the Harrach in Algiers, announced as emeralds by M. Ville, have proved to be tourmalines, analogous to the somewhat rare variety met with at St. Gothard, and in Elba. They were first discovered in 1855, in a crystalline limestone associated with gypsum and diorite, about ten miles east of Blidah. (Bulletin de la Société Géologique de France: tome XIII, page 416.) Most tourmalines when treated with salt-of-phosphorus before the blow-pipe, effervesce and dissolve readily; but this pale green variety, curiously enough, behaves just like the emerald: exhibiting a scarcely perceptible effervescence, and dissolving very slowly.

CYSTIDEANS.

Mr. Billings, palæontologist to the Geological Survey of Canada, has discovered in the Chazy limestone near Montreal, a new Cystidean, more or less allied to Cryptocrinus by its three basal or pelvic plates, but differing from that genus by

Some, although probably but a small portion, may be taken up by marine vegetation, as seven per cent. of silica appears to have been detected in the ashes of fucus vesiculosus. The ashes of most sea-weeds, however, contain no more than one or one-and-a-half per cent. of silica. E J. C.