The preparations for the International Health Exhibition to be opened in London in May next, proceed very rapidly. The eight water-companies which supply London, and which just now are being so roundly abused on the score of overcharges, will exhibit the various apparatus employed by them for the supply, filtration, &c., of water. They will also combine in erecting an immense fountain in the grounds, the jets of which will be brilliantly illuminated at night by electricity.
An American paper gives an interesting account of the manufacture of ‘Yankee sardines,’ which may be explained to the uninitiated to mean small herrings preserved in oil and flavoured with spices, to imitate the sardines of French preparation. To begin with, the fish are laid in heaps on long tables, where they are rapidly cleaned and decapitated by children. The herrings are then pickled for one hour, to remove a certain tell-tale flavour which they possess, after which they are dried. The next operation is to thoroughly cook them in boiling oil; and finally, they are packed in the familiar square tins, and duly furnished with a French label, such as, ‘Sardines à la Francaise,’ or, ‘A l’huile d’olive.’ The free, or rather the true translation of this latter inscription would be, ‘cotton-seed oil,’ and, sad to say, not always of the first quality.
A paper dealing with an outbreak in a German town of that terrible disease known as trichinosis was recently read before the French Academy of Medicine. It is worthy of attention as going far to prove that this disease, usually contracted by the consumption of unwholesome pork, is avoidable, if the ordinary precaution of thoroughly cooking the food be resorted to. In the case in question, more than three hundred persons were attacked with the disease, and of these nearly one-sixth died. It was proved beyond question that all the victims ate the meat absolutely raw, it being the custom to chop it fine and to spread it like butter on slices of bread. One single family, which consumed some of the same meat in the form of cooked sausages, exhibited no trace of the disease. It may be mentioned that a certain dose of alcohol exercised a most favourable effect in diminishing the virulence of the complaint.
A new system of railway signals which is worked by electricity, instead of by mechanical leverage, has lately been experimented upon with great success, but like most other things of an electrical kind, its ready adoption must depend upon its expense as compared with that of the older-fashioned plant. Hitherto, the ordinary electric magnet has been found unequal to this class of work, principally because its power of attraction is only great when very near the object to be attracted, and also because its impact on its armature is so violent as to lead to risk of deranging the apparatus employed. By use of what is known as the long-pull electro-magnet, recently invented by Mr Stanley Currie, these difficulties have been obviated, and signals of every kind can be worked most perfectly through the medium of conducting wires. The system has been at work for the past two months at Gloucester, and is being adopted experimentally in other directions.
The volcano at Krakatoa will long be remembered, if only on account of the wide area over which its products have been distributed. To say nothing of the dust particles which are supposed to have found their origin there, and which are credited with having been the active cause of our late gorgeous sunsets, undoubted volcanic particles have lately been found at Philadelphia. By melting and evaporating the snow upon which these tiny fragments were found, a residue of solid particles was apparent, which the microscope at once pronounced to be of a volcanic nature. It seems difficult to believe that solid matter could thus be carried in the air for four months, during which it must, if it came from Krakatoa, have covered the enormous distance of ten thousand miles. Another supposition is that the volcanic particles found at Philadelphia may have been wafted thither from Alaska, in the north-west corner of North America, where a great eruption has occurred. According to our authority, a submarine volcano shot up there last summer, and has already formed an island in the Behring Sea, from eight hundred to twelve hundred feet high. It is therefore possible that volcanic dust may have found its way, from this source, to the southern states of America, and even to Great Britain. The enormous distances traversed by these glassy particles may be thus accounted for: when steam is forced through a mass of glassy lava, the molten material is shot up with it in the form of thin filaments, just like spun glass. These, like so many pieces of spider web, would be borne aloft by the air for a very long period.
It seems only yesterday that iron furnace slag was looked upon as a waste product, for which no possible use could be found. It is now made into bricks, into cement, into wool-packing for steam-boilers, and more recently it has been found a most effective material for making all kinds of vases and other things of an ornamental nature. For this purpose, the slag is freed of its coarser particles, mixed with a certain quantity of glass and colouring matter, and when in a molten condition, is stirred about so as to present a veined appearance. It is then moulded into various forms, and is ready for sale.
We lately had an opportunity of visiting the Fine Art Loan Exhibition at Cardiff, which has been opened for three months, for the purpose of collecting funds in aid of the projected Cambrian Academy. The Exhibition includes works by some of our most eminent artists, both living and deceased, as well as a collection of such articles as can be grouped under the head of Art. But a novel feature of the Exhibition is its complete array of telephonic and telegraphic apparatus. By the co-operation of the telegraphic authorities, communication has been opened up by telephone between the Exhibition and Swansea, a distance of fifty-two miles. Not only is speech quite easy over this distance, but the voices of those acquainted with one another are readily recognised. At the time of our visit, the apparatus was connected with the theatre at Swansea, and we had the curious experience of listening to chorus, band, and solo voices, which were rendering a popular opera more than half a hundred miles away.
Mr J. C. Robinson, in the course of an interesting article contributed to the Times on the conservation of Sir Joshua Reynolds’s pictures, concludes with a recommendation which all owners of valuable oil-paintings should take note of. He strongly advocates the use of glass as a covering for such pictures, and is glad to see that the practice of thus framing them is on the increase. ‘This plan,’ he says, ‘almost entirely obviates the necessity for the periodical rubbing up and cleaning the surface of pictures with the silk handkerchief or cotton-wool, inasmuch as the protecting glass, and not the painted surface of the picture, receives the rapidly accumulating deposit of dust and dirt.’ But even this he considers to be only a half-measure. The back of the picture should be stretched over with a damp-resisting sheet of india-rubber or American cloth, for it requires protection only second to the painted face of the canvas.
In presenting the gold medal of the Royal Astronomical Society to Mr A. Common for his wonderful photographs of celestial objects, the President of that honourable body gave a most interesting history of the medallist’s gradual progress in the difficult work in which he so much excels. Mr Common commenced work with a modest reflecting telescope of five and a half inches; but he was not satisfied until he had obtained one measuring no less than three feet across its mirror. He has also turned his earnest attention to the clockwork for driving the instrument, so that as the busy world turns on its axis, the objects focused remain stationary. This is highly necessary, when it is remembered that sometimes a star photograph occupies as much as an hour and a half in the taking, even with the most sensitive plates. This long duration of the action of the feeble light from stars so remote that they cannot be seen by the naked eye, has the effect of impressing the chemical surface so that the invisible is pictured! It is evident that a new field of research is thus opened out; and the President did well in pointing out what great services can be rendered to knowledge by the amateur worker who, like Mr Common, has the means and the ability to employ his time so well.
In these days of oleomargarine, bosch butter, and other mixtures which are supposed to furnish excellent substitutes for the genuine article, it becomes highly necessary to have some means of distinguishing the true from the false. A contribution to microscopical science towards this end is a test discovered by Dr Belfield of Chicago, which will at once identify a fat if it consist either of lard or tallow. Pure lard crystals exhibit thin rhomboidal plates, while those of tallow are quite different, and are of a curved form somewhat resembling the italic letter f.