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small price, and replace the clumsy and objectionable "live-box." In size and shape the Cheap Compressorium resembles two ordinary glass slides, one overlying the other. It is made of two pieces of brass—one carrying the cover, and the other the glass bed. It is raised by springs, and depressed by two screws easily worked. We have tried it with various objects, and can recommend it. As soon as an approximation to contact is obtained, the screws must be worked alternately, and very gently. Mr. Curteis' slide-cells are modifications of a plan introduced by Mr. Richard Beck. The cell is formed in an ordinary slide, with or without a back, according to its depth. The cover turns upon a pivot. They work well, provided the cover is quite free from grease ; and this condition is easily obtained by washing it with a little caustic soda.
DAY VIEW OF VENUS WITH SMALL TELESCOPE.-Mr. Levander, of Canon. bury, writes to us, that on the 20th of October, 2h. 50m., he saw Venus when only about 25m. 56s. east of the sun, and 9":6 in diameter, with an inch and a half telescope, mounted equatorially by himself, and a power of about 90. A cloud obscured the sun at the time.
TEST FOR OZONE.-During a recent discussion at the French Academy on the difficulties of Ozonoscopy, M. Le Verrier stated that, when the subject was discussed last May at Metz, M. Schönbein pointed out that a colourless solution of the protoxide of thallium became yellow under the influence of ozone, and was not, like the iodine test, affected by nitrous compounds ; but, unfortunately, the subject was not yet brought to a practical state.
FREE SULPHURIC ACID IN MOLLUSK3.-In addition to the Dolium galea, MM. St. Lucca and Panceri inform the French Academy that they have disa covered free sulphuric acid in the glands of Tritonium corrugatum, T. cutaceum, and T. hirsutum, Cassis sulcosa, Cassidaria echinophora, Murex trunculus, M. brandaris, Aplysia cornatus, and others (not named). They observe—“Free sulphuric acid is thus found to be an element necessary to the organic functions of a numerous class of mollusks, living in stony localities, and carrying a shell formed almost exclusively of carbonate of lime, accompanied by traces of carbonate of magnesia. The strong acid is found in company with a weak acidcarbonic."
ELECTRICITY AND VEGETATION.-M. Ch. Blondeau states (“Comptes Rendus," Nov. 4, 1867), that subjecting fruits-apples, pears, and peaches-to the action of an induced electric current hastens their maturity. Having rendered seeds good conductors by moistening them, he affirms that electrizing them by induced currents causes them to germinate earlier than similar seeds not subjected to such action. He says, “Some haricot beans which were electrized exhibited a singular peculiarity. They germinated head downwards, and root upwards, in the air. That is to say, the gemmule, surrounded by its cotyledons, remained in the ground, while the root, separated by a little stem from the gemmule, erected itself in the air. This fact appears important, as explaining the reason why plants push their roots into the earth, and their stems into the air. This tendency is so strong, that efforts to cause them to act otherwise are fruitless; but it may be overcome by the electric shock, in the same way as the poles of a magnet may be reversed. We are tempted to liken the embryo to a small magnet with opposite
HYBRID COTTON.-M. J. E. Balsamo states (“Comptes Rendus") that, by artificial fecundation, he succeeded in obtaining hybrids between the Nankin cotton-plant and the Gossypium barbadense, and vice versa. In both cases the cotton obtained was of a character intermediate between the two types.
LIGHT AND VEGETATION.—The same observer planted cotton-seeds in a glass vessel at various depths of garden mould, and in contact with the glass side. Some were protected by yellow paper gummed to the glass, and others left exposed to the light. The former began to grow in nine days, while the latter were found to be slightly decayed at the end of ten days.
NEw MUD-FISH FROM NEW ZEALAND.-In" Annals Nat. Hist.” for November Dr. Günther describes a new mud-fish sent to the British Museum by direction of Sir G. Grey. It is about 51 inches long, possesses the general characters of Galaxias--scaleless fresh-water fishes, of which five out of twelve known species belong to New Zealand, New South Wales having three, and Van Dieman's Land two. “Eastwards the same genus is met again in the southernmost parts of America (Falkland Islands, Patagonia, Terra del Fuego), and a minute form occurs in Chili." Dr. Günther names the new fish Neochana apoda. It has a broad, obtusely-rounded snont, mouth-cleft moderately wide, the maxillary extending below the eye, which is very small. Anterior nostril prolonged into a minute tube; several wide pores at the upper part of the head. A rather deep groove from the head along the middle of the back and abdomen. Dorsal and anal fins about as high as the tail between them, and both continuous at the base with the rudimentary rays of caudal fin. Caudal fin rounded, as long as head without snout; pectoral somewhat shorter. Brown, with irregular, blackish, transverse spots. Dr. Hector states that it was found four feet from the surface, in a stiff clay, embedding roots of trees, in a locality thirty-seven feet above the Hokitika River, three miles from the sea, which was at one time a backwater of the river during floods. Two years ago it was a swamp, but the miners pierced through the clay to a bed of gravel, and drained it. Dr. Hector adds, “Mr. Schaw, the Warden of the District, has examined seven or eight specimens of this fish, and assures me they occur in hollows of the clay, and that although when first extracted they moved freely, if placed in water they get sluggish, and soon die.” He further states that the early settlers in Zealand were frequently astonished at digging up fish as well as potatoes. All these fish are very fat, and Dr. Günther found this one quite greasy.
THE NEWTON FORGERIES.—There seems now every reason to believe that the extraordinary mass of forged correspondence in the possession of M. Chasles, and which he has defended with such remarkable and ill-judged pertinacity, was fabricated by Desmaiseau between the years 1732 and 1745. He was a collector and dealer in autographs. Sir. D. Brewster says that the celebrated deist, Anthony Collins, the friend of Locke, left him his MSS, to be published after his death; but he sold them for fifty pounds to Mrs. Collins, by whom it appears they were destroyed.” Internal evidence at once showed that Sir Isaac Newton could not have written the letters ascribed to him ; and the more the correspondence has been examined, the stronger has been the proof that the whole collection was fictitious.
ELECTRO-CAPILLARY CURRENTS IN PLANTS.—M. Becquerel eleucidates this subject in “ Comptes Rendus." He says that he makes a transverse section of the stem of a young poplar, oak, or maple in full sap, and introduces two nonpolarized platina needles, in connection with a very sensitive galvanometerone in contact with the central pith, and the other with one of the ligneous layers. An electric current is immediately manifest, and by its direction indicates that the pith is always positive, relative to the other parts. The maximum of effect is produced when the second needle is placed between the woody layer and the bark. The positive condition of the layers augments towards the pith. From this state of things it follows that the liquid which moistens the pith, and the cellular tissue in general, is more oxygenated than what is found in other parts of the plant. In leaves the cellular tissue is positive, with relation to other parts. The earth is found positive in relation to the roots of plants, and their stem and leaves; that is to say, in relation to the liquids which moisten them.
THE WALRUS AT TIE ZOOLOGICAL GARDENS.-We recommend all our readers who have not already done so to go and see the young walrus at the Zoological Gardens. He answers to the name of “Jemmy," and seems both tame and good-natured. He has improved much in appearance since his arrival, and thrives upon a diet of fish and porridge. A few days ago Mr. F. Buckland tried to tempt him with some shrimps, as “Land and Water" tells us, but he did not condescend to eat them, though fond of whelks and mussels. He does not walk as well as the sea-bear, nor manifest as much agility ; but he is only a youngster, and has not had much pains taken with his education. He is now in the large pond with the seals.