THE MONTH:SCIENCE AND ARTS.
Thelate meeting of the British Association at Birmingham has proved a success with regard both to the attendance of members and to the importance of the various papers read in the several sections. Next year the Association will meet at Manchester, and the year after at Bath. The suggestion from Sydney, that the Association should in 1888 visit New South Wales and hold its meeting there in the January of that year, cannot, on account of many difficulties which are foreseen, be accepted in its entirety. But it is intended that about fifty members shall form a representative delegation to our Australian colony, their expenses being liberally defrayed by the government of New South Wales. It is very pleasing to record this little sign of the good-fellowship which exists between far-off Australia and the mother-country.
We expressed a hope some months ago that an institution of a permanent nature might grow out of the splendid Indian and Colonial Exhibition at South Kensington, which in a few days will close its prosperous career. It has now been proposed by the Prince of Wales that the Jubilee of Queen Victoria’s reign shall be commemorated by an Institute which should represent the Arts, Manufactures, and Commerce of Her Majesty’s Colonial and Indian Empire, and which should be at once a Museum, an Exhibition, and the proper locality for the discussion of Colonial and Indian subjects.
Very little is heard now of tempered or toughened glass for domestic purposes, although, a year or two back, such glass was much advertised and its praises constantly sung. We understand that the reason why it has at present disappeared from public notice is that its efficiency does not last. When fresh from the factory, it can be dropped from a height on to the floor and knocked about with impunity. But some gradual and not understood change occurs in its constitution, for after a short time it will fly to pieces without any apparent cause. It is said, too, that unscrupulous traders who have a stock of the faulty material are selling it as ordinary glass. Those, therefore, who experience unaccountable breakages, will know to what cause to attribute them. A really unbreakable glass would be such a boon, that it is to be hoped that further experiment will soon show how it can be manufactured.
From some recent experiments in New York, it would seem that the danger of using dynamite as a charge for explosive projectiles has been obviated. The weapon used was a four and a half inch rifled gun, with a charge of three and a quarter pounds of gunpowder, the experimental shells holding each more than one pound of dynamite. To avoid any risk from concussion, and premature explosion of the shell in the bore of the gun, the cartridge and shell were separated by wads made of asbestos. Twenty-seven shells were fired with such safety to the gunners, that the extraordinary precautions observed during the first rounds were ignored during the later ones.
The boat which the other day twice crossed the Channel between Dover and Calais affords an example of the rapid progress which has lately been made in the science of electricity. This little craft, which is only thirty-seven feet in length, glided over the water with no visible means of propulsion. The voyage was an experimental one, and was designed to show that this plan of electrical propulsion was as practicable on the sea as before it had been proved to be on inland waters. Such a boat could, say her promoters, be carried hanging to the davits of a ship, and be ready for immediate use. The required electrical current is derived from accumulators, or secondary batteries, stored and acting as ballast beneath the deck floor of the little vessel. These require to be charged by a dynamo machine at intervals, and such a charge this Channel trip amply proves will suffice for a run of between forty and fifty miles. Supposing that the system were adopted for torpedo vessels, it is obvious that this amount of storage capacity would be far more than sufficient for ordinary needs.
Another vessel which obtains its motive-power from a very different source, but which must also be looked upon as an experimental boat, has been invented and built by Messrs Secor of Brooklyn. Unlike the electric boat, it possesses no screw propeller or other moving parts. But it is furnished on each side with open ports below the water-level, which are in communication with an ‘exploding chamber.’ This chamber is constructed of steel, and is capable of sustaining an enormous internal pressure. It is filled with charges of petroleum vapour and air under pressure, and this explosive mixture is ignited by electricity. It will therefore be seen that the propelling apparatus of this boat may be compared to a gas-engine; but the explosions, which occur several times in a minute, instead of forcing forward a piston to act upon a fly-wheel, impinge upon the water at the stern of the vessel, and so push the boat forward. Should this method of driving a vessel through the water prove efficient, it will certainly be economical, for little more than half a barrel of petroleum will suffice for a twenty-four hours’ run.
Another invention from Brooklyn is of far greater importance than the one just recorded, for it is of a life-saving character, and is designed to prevent those collisions at sea which seem to be so greatly on the increase. It consists of a marine brake, and is the contrivance of Mr John M‘Adams. The experimental vessel,The Florence, which is fitted with the brake, has been reported upon officially, and the behaviour of the apparatus is highly commended. The brake consists of two wings made of steel, one on each side of the vessel and below water-level. These have the appearance of flat boards about eight feet square, hinged to the stern-post, and which when not in action fold forwards, secured by hidden chains, close to and touching the vessel’s sides. In case of danger of collision, the touch of a button by the captain on the bridge will loosen these chains, and cause some springs to act upon the wings, so that they fly out at right angles to the sides of the ship. In this position they are held by the now lengthened chains, and form an obstacle to the water, which checks the motion of the vessel immediately, even if the engines continue to work. If the engines are stopped at the moment the brake is put into action, the ship is brought to a standstill in twenty-two seconds. If, again, the engine be stopped and reversed at the moment of working the brake, the vessel commences to go astern in the remarkably short space of twelve seconds. It will be seen from these results that the invention gives every promise of being of great use. Besides being efficient, it is simple in character, and, from its nature, cannot be a very expensive additional fitting to a ship.
The lamentable accident at the Crarae Quarries, by which seven persons lost their lives, is happily a most unusual one, although in character it is closely allied with those fatalities from ‘choke-damp’ by which so many poor colliers have been killed. The explosion of gas underground, or of gunpowder above ground, leads to the evolution of a quantity of carbonic acid gas, or, to call it by its proper name, carbon dioxide, the principal product of combustion in either case. In the workings of a mine, this gas fills every available space, and has no outlet. In the quarry, on the occasion referred to, much the same condition of affairs existed, for there was no wind to carry off the deadly vapour, and its natural heaviness made it cling to the place of its creation. The surviving relatives of the victims of this accident have our heartfelt sympathy. They will be comforted by knowing that death under such conditions is supposed to be painless. It is a sending to sleep, but a sleep, unfortunately, from which there is no awakening in this world.
The little town of East Moulsey is now lighted, so far as its public lamps are concerned, by paraffin instead of gas, as heretofore. The reason of this apparent retrogression is found in the excessive demands of the Gas Company, who required the local board to pay at the rate of four guineas per annum for each lamp. This the local board refused to do, and provided the district under their care with paraffin lamps. They are rewarded for their pluck by finding that the cost of the oil-lamps is but one half of the charge demanded by the Gas Company, and by hearing the generally expressed opinion of the people that the place had never before been so well lighted.
The recent earthquakes, which have caused such fearful havoc and loss of life both in Southern Europe and in America, remind us that our knowledge of the causes of such terrible phenomena is very meagre, and that science has not yet discovered any means by which their occurrence may be predicted. But, in spite of these admitted facts, there are not wanting on occasions of earthquake self-styled prophets, who will boldly declare what the morrow will bring forth. Such mischievous charlatans do much harm, for they terrify the ignorant at a time when men’s nerves have been already unstrung by recent calamities. In the year 1750, when London felt a sharp earthquake shock, a prophet announced the immediate coming of the judgment day. Another predicted a terrible earthquake for a certain night, with the result that the people encamped in thousands in Hyde Park. Coming nearer to present times, we may note the destructive earthquake in 1881 in the island of Ischia. Here, again, there was a prophecy that there would not be another visitation of the kind for eighty years. But only two years after this the beautiful island was shaken to its foundations, and many lives were lost. During the late disaster at Charleston, a prediction was made that upon the 29th of September a fearful catastrophe was to take place. The originator of this mischievous statement should be severely punished.
We have lately received from Messrs Burton Brothers of Dunedin, New Zealand, a set of most interesting photographs, taken in the neighbourhood of Tarawera and Rotomahana, immediately after the late volcanic eruption. Were we not aware of the terrible facts, we should suppose that these were winter scenes, for the trees are stripped of their foliage, and everything is covered with a white ash, which in the photographs looks likes snow. The ruins of M‘Rae’s hotel at Wairoa, of which there are front and back views, exhibit such a mass of broken masonry and twisted iron-work, that one can hardly believe that the place has not been bombarded.
We are glad to learn, from theNew Zealand Herald, that the layer of ashes which covers so many miles of the country, will not, as was at first feared, choke and kill every blade of grass, but will probably in time act as a valuable fertilising agent. Already the grass is in many places growing up through the dust; but the ash has been submitted to experiment, and is found to be really nourishing to plants grown in it. Mr Pond, a resident analytical chemist, obtained several samples of the volcanic dust, and sowed in it grass and clover seeds, and kept them moistened with distilled water. In each case, we are told, the seedling plants have come up well and are growing vigorously; it is therefore hoped that those districts which have received only a light covering of this dreaded dust will find that the visitation will in the end prove beneficial to their crops.
As we stated last month, the armour-plated shipResistancehas lately formed a target for various experiments with different types of guns. The unfortunate old ship is now being subjectedto attacks by torpedoes, the object being to determine the nearness at which one of those submarine mines can be exploded without injury to a vessel when protected by wire-netting. It is proved that if the defensive netting is supported on booms thirty feet from the ship, it forms a good protection from torpedoes, and that though a torpedo should explode on touching the netting, as it will do if fitted with the new form of pistol trigger, which is very sensitive, the explosion will do no great harm. The distance of the netting from the ship will be gradually reduced until theResistancecan resist no longer, and must be destroyed.
A strange sight was lately witnessed at Salzburg, in the shape of a vast procession of butterflies, which passed over the city in a south-westerly direction. They seemed to fly in groups, and while preserving one line of direction in flight, the groups revolved round that line. This aërial insect army must have numbered millions of individual butterflies. From those which fell to the ground, it was seen that they were of the kind known as willow-spinners.
Photographic tourists—and their name now is legion—will all admit that their greatest drawback is represented by the weight of the glass plates which they must carry from place to place in addition to their other apparatus. This difficulty has just been obviated by the introduction of a material as a support for the photographic image which is as light as paper, so that in the compass of an ordinary two-shilling railway novel, the tourist can carry with him the sensitised material for a couple of hundred pictures. This material is known as Woodbury tissue, and was the last invention of the late eminent experimenter who gave his name to the beautiful Woodburytype process of photography. His successors have brought the tissue to marketable perfection, and produce a material as translucent as glass and one-twentieth part of its weight. The tissue is used in a singularly ingenious form of dark slide or double back, which can be readily adjusted to existing forms of cameras.
In theCameramagazine, a very curious phenomenon in connection with photography is recorded by the person who observed it. He took a portrait of a child apparently in full health and with a clear skin. The negative picture showed the face to be thickly covered with an eruption. Three days afterwards, the child was covered with spots due to prickly heat. ‘The camera had seen and photographed the eruption three days before it was visible to the eye.’ Another case of a somewhat similar kind is also recorded where a child showed spots on his portrait which were invisible on his face a fortnight previous to an attack of smallpox. It is suggested that these cases might point to a new method of medical diagnosis.
The Severn tunnel, one of the greatest engineering undertakings of modern times, is at last finished, and will be shortly open for passenger traffic, as it has been some weeks for the conveyance of goods. The total cost of this great work is estimated at two millions sterling. The cost has been greatly augmented by the unlooked-for difficulties which have cropped up during the progress of the works. Commencing in 1873, the contractor had made steady progress for the following six years, when a land spring was accidentally tapped, and the partially constructed tunnel was flooded. Again, in 1881 the seawater found out a weak place on the Gloucestershire side of the works, and poured in in torrents. Once more, in 1883 the old land spring again filled the works with water, which had to be pumped out; and finally, about the same time, a tidal wave brought about a great amount of destruction to the works; so we may look upon the completed tunnel not only as a great monument of engineering skill, but as an example of unusual difficulties well grappled with, and finally overcome.