« PreviousContinue »
nary lead line ceased to be available, or at all events convenient; and until very recently the difficulty of calling up a long line and heavy weight from considerable depths was so great that it had become the practice to leave the weight behind, simply bringing up the specimen of the bottom. The Admiralty had made great improvements in deep sea soundings, but even with the rope now used its resistance to the water when drawn up by hand at considerable speed was so dangerous as to necessitate the use of steam power. When there was great resistance to the line, and the currents carried it away to a distance, it was difficult to know when the bottom was reached. However, he believed that with so great a weight as 3 cwt. the bottom might practically be perceived within a few fathoms, and, although it must be difficult to stop the line all of a sudden, he did not think the error in the sounding could be considered to be serious. To many it had occurred that wire rope would be a great advantage, inasmuch as it would occupy much less space and, therefore, create less resistance to the water. The objections which had been raised to wire were, that it was liable to rust, that the men could not handle it as it would kink, and it would go down in a heap over the weight; but he believed all those difficulties might be overcome by proper care. It had been considered necessary to have a great deal of mechanism, but all that he deemed to be essential was a wheel which operated like a break, and around which the wire should be twined; the wire used being No. 22 gauge, of the quality known as the homogeneous steel wire, which could be manufactured in great lengths, was •03-inch in diameter, weighed 12 lbs. per statute mile, and broke with a weight of 252 lbs. To the end of the wire was attached a piece of hemp cord, which carried the weight, and by that means the wire was prevented from touching the bottom at all. He had made an experiment in mid-ocean, at a depth of 2,700 fms., experiments with the apparatus and materials he had indicated; and, it having been attended with the most perfect success, he was sanguine that, if wire were allowed to take the place of cord in deep sea soundings, it would be far more economical, and so the calculations themselves would be more accurate.
Aërial Navigation. This formed the subject of a paper read at the British Association in Brighton by Mr. C. A. Bowdler, in which he expressed the opinion that the autumn manquyres would be an excellent opportunity of trying experiments, and that aërostation would become an important element in military science. Hitherto, captive balloons only had been used, but it was by no means improbable that circumstances would occur where it would be most desirable to pass over the enemy's position, and it would then be important to have the power of severing or deflecting the balloon from the wind-course, either to right or left as required. Captive balloons could not be used in safety in high winds on account of violent rocking of the car. The writer then proceeded to review the elements of aërostation, and to show that aërial navigation was practical to a certain limit by simple mechanical means. Of the practicability of apply. steam power he had no hope, the weight of a steam engine made as light as possible, consistent with due strength, being much too great for any gas balloon to support. The power he proposed was manual, being, he believed, the only power applicable to gas balloons. But propulsion having been
secured, the question arose how the power of direction could be acquired, that being of the utmost importance in actual warfare. That was accomplished by rotating the balloon to any required position, and then, holding it from further motion, the rotation was completely under the control of the aëronaut. A rudder was the instrument to be used for that purpose, a vertical disc fixed in a line with the axis of the propellor. By turning the plane of the disc the current of air forced from the fan on the rudder caused the whole machine to rotate right or left precisely as the rudder of a ship guided the vessel.
Report on vinfall.–At the meeting of the British Association in Brighton, Mr. G. J. Symons, Secretary of the Rainfall Committee, produced the Report of that committee, which was as follows :-“Your committee hare the honour of reporting that every branch of rainfall work continues in efficient working order, and that, notwithstanding the very limited funds at our disposal, and the long illness of our secretary during the winter, all arrears have been overtaken, and, owing to the completeness of the organisation, no hitch or interruption occurred. At the meeting of the British Association in Edinburgh very strong representations were made to your committee respecting the desirability of establishing additional raingauge stations in different parts of the highlands, and as your committee bad long been aware of the necessity which existed for these stations, and, moreover, as somewhat larger funds than usual were at their disposal, they resolved on taking every means in their power to secure the efficient establishment of these stations. In addition to ordinary correspondence, our secretary took two special steps to secure the most promising distribution of the new gauges. In the first place he wrote to Mr. Buchan, the secretary to the Scottish Meteorological Society, acquainted him with the assent of the committee, and requested him to state what number of gauges he could provide good observers for. On receipt of his reply, ten gauges were sent to him, which he was kind enough to distribute as follows:-1. Springfield, Tain, Ross; 2. Kilmalcolm, Port Glasgow; 3. Arrochar, Loch Long; 4. Strahane, Brodick, Arran; 5. Strathfillan, Perthshire; 6. Samrose, Arran; 7. Kilchoman, Islay ; 8. Port Charlotte, Islay; 9. Port Ellen, Islay; 10. Glenharn Abbey, Mull of Cantire.”
Powerful Galvanic Battery.-Nr. Highton described, at the British Association in Brighton, a new form of battery capable of giving powerful effects without fumes or other inconveniences. Negative: Carbon packed in a porous cell, with sulphur, peroxide of manganese, and granulated carbon, filled up with dilute sulphuric acid; Positive : zinc in a solution of caustic potash or soda. The potential is nearly fifty per cent. higher than Groves. One cell will abstract magnesium from its salts.
ZOOLOGY AND COMPARATIVE ANATOMY. Supposed New Marine Animal.–At the British Association Meeting, Dr. Sclater, F.R.S., exhibited specimens of bodies having the general external shape and appearance of long, thin, tapering, white willow wands, which he
had received from Captain David Herd, of the Hudson's Bay Company's service, with the information that they had been brought by that Company's vessels from Barrand's Inlet, Washington territory, North-West America. The captain who brought them stated that they were the backbones of a gelatinous fish, shaped like a conger-eel, very common in that inlet, which swam about in shoals with the dog-figh; that in the living animal the backbones were also transparent like the rest of the animal, but became ossified when dried on the beach. Dr. Gray, of the British Museum, recently described these rods as the axis of a pennatulide animal, and referred it to his genus Osteocella under the name 0. septentrionalis ; but Dr. Sclater, supposing the facts supplied him to be correct, considered the “rods” to be the ossified notochords of some low organised fish, with the skeleton wholly cartilaginous, partially belonging to the lampreys or to the chinæroid group.
A new Asiatic Rhinoceros.—Dr. Sclater, F.R.S., read a paper on a “New Asiatic Rhinoceros," with remarks on the recent species of the genus. On the 14th of February last, he said, the Zoological Gardens of London received a female two-horned rhinoceros, which had been captured near Chittagong four years previously. This animal had been referred to Rhinoceros Sumatrensis of Cuvier by the author and other writers, that being the only species of the two-horned section of rhinoceros hitherto recognised by naturalists. The acquisition of a female of the veritable Rhinoceros Sumatrensis from Malacca had enabled the author, after comparison, to conclude that the first-mentioned specimen belonged to a different species, which he proposed to call Rhinoceros lasiotis, on account of its most obvious external peculiarity being the long hairs which fringe the ears. The existing number of rhinoceros certainly known he considered to be six, of which four belonged to the Asiatic group and two to the African group.
Rheumatism in Whales.-Professor Struthers made a communication to the British Association on the sternum and pelvic bones in the right whale and in great fin whales, showing great variations in form, even in different species. He mentioned a curious circumstance in the osteology of whales, viz., that these animals are very liable to rheumatism. He had, he said, seen many examples of rheumatic ostitis in whales of different kinds. It had been said that animals were not subject to disease until they were brought into connection with man; but the fact he had mentioned contradicted the theory. It was the more remarkable, seeing that whales were less liable than man to variations of temperature; and the cold water cure (as a witty friend had observed) did not seem to be efficacious in the cure of the disease in question. The Professor made a communication also on the occurrence of finger-muscles in the bottle-nose whale (Hyperodon bidens). A dissection of the fin of a whale of this species (a male 20 feet in length) was exhibited, showing the presence of finger-muscles corresponding to those in man, and also (according to the Professor) the biceps muscle transferred from the scapula to the head of the humerus. A piece of the gum of the lower jaw was likewise shown, in which a concealed tooth was sunk about half an inch below the surface. He asked what could be the use of teeth in such a position ? He could only infer, from the existence of such rudimentary structures, that the animal was descended from a species possessing functional teeth. Professor Flower attributed the great variations in the pelvic bones and the sternum of the whale to their rudimentary character.
Sir John Lubbock's Tame Wasp.-Sir J. Lubbock exhibited a tame wasp which he had brought with him from the Pyrenees, and which had been in his possession for about three months. The wasp was of a social kind, and he took it in its nest formed of twenty-seven cells, in which there were fifteen eggs; and, had the wasp been allowed to remain there, by this time there would have been quite a little colony of wasps. None of the eggs, howerer, came to maturity, and the wasp bad laid no eggs since it had been in his possession. The wasp was now quite tame, though at first it was rather too ready with its sting. It now ate sugar from his hand and allowed him to stroke it. The wasp had every appearance of health and happiness; and, although it enjoyed an outing occasionally, it readily returned to its bottles, which it seemed to regard as a home. This was the first tame wasp kept by itself he had ever heard of.
Norwal and Abnormal Growth of Lymnæus.—Professor Carl Semper read a paper at the British Association, in which he stated that numerous experiments made during the last few years have shown that, by separating individuals of the same generation, and by rearing them under the same conditions, the separated individuals grow more rapidly than those remaining and reared in company together. Through these experiments it became possible to draw certain curves of growth which show that, under the most favourable conditions, the growth may be divided into three distinct phases - the first being of slow growth, the second of very rapid, and the third of a very slow one again. The fact, that isolated individuals brought up under the same conditions-namely, the same quantities of water, the same surplus of food in the same temperature and isolation-acquire a greater length in the same time than those brought up in numbers together under the same conditions, is not a new one. But the explanation given, for instance in the case of fresh-water fishes, that this difference of growth depended entirely on the influence of the greater or lesser quantity of food, may be correct for the fishes, but is entirely wrong for the lymnæus. It is neither the quantity or quality of food, nor temperature, carbonate of lime, or other known influences, which determine the growth of the animal. From known experiments, it may be inferred that there will be found, in pursuing these investigations, that there may exist in the water a substance, the presence of which, at a certain low percentage, will determine the growth of the animal. This substance, which probably will be choloride of calcium, will act in the organism like the oil does in the steain-engine, viz. without its being there the animal will be unable to digest its food, while, being there in an almost imperceptible quantity, it renders growth possible. Thereby it is shown that the forces of molecular activity play an important part in the growth and formation of animals and animal tissues. The important part of physical science called molecular science must now always be taken into consideration in studying the development and growth of animals in general.
The White Coffee-Leaf Miner. -An American naturalist bas given an interesting paper on this subject in the “American Naturalist” (June). The
VOL. XI.—NO. XLV.
habitation of the larva is a mine, which is made in the leaf by eating out the soft green substance (parenchyma) between the upper skin (epidermis) and the framework of the leaf, laying the framework bare, but leaving the epidermis intact, except at the point where (he supposes) the larva enters the leaf. At this point the wound heals up and forms a lenticular scar twentyfive hundredths of a millimeter in length, and fifteen hundredths of a millimeter in breadth, raised a little above the general surface of the leaf. The epidermis which covers the mine becomes rusty brown, sometimes almost
surface. Sometimes a portion of the under surface of the leaf opposite the mine also turns brown. When the eggs are laid in sets, the mines of the separate larvæ usually become united, and even the mines of two sets may be united into one. One mine, fifteen millimeters long and ten millimeters broad, contained seven larvæ, the scars arranged in two groups of four and three respectively. Another scur was near. As many as five mines, all inhabited, have been found on one leaf, and even eight mines made by ten larvæ, though in this case some of the larvæ had escaped.
Association by M. Georges Pouchet on the mechanism of the changes of colour in fishes and crustacea. The author referred to the fact that fishes often change in colour according to the colour of the objects by which they are surrounded : but he explained that this does not take place when the fish is deprived of the nerves that preside over the peculiar corpuscles to which the colour is due. The change does not take place in blind turbots; and in the seeing turbot, if the nerves are divided which communicate between the eye and the skin, the change does not occur. If the fifth nerve is divided, the change takes place all over the body except the part to which that nerve is distributed. These experiments, M. Pouchet said, show that the change of colour is dependent upon impressions received by the nervous system through the organs of vision.