Some months ago we mentioned the little torpedo boat Lightning, and her swift steaming, nineteen knots an hour. Her length is eighty-four feet, her width ten feet ten inches: and now we hear that fifteen similar vessels are to be built, and that the builders promise a speed of twenty-five knots. Experiments have been made which prove that swiftness is an element of safety, for on firing a rifle-bullet through the bottom it was found that the water did not enter. In future it is thought that torpedoes will play an important part in naval warfare; and as has already been mentioned in recent papers in this Journal, a School has been established at Portsmouth in which their use is taught theoretically and practically. A further improvement is whispered in certain quarters—a torpedo boat which shall carry on her evolutions under water, and hook on torpedoes to the bottom of an enemy’s ship without being discovered. Are we about to see in this a realisation of what has long been a dream among speculative inventors? Is naval warfare, from its hopelessly fatal nature to those engaged, to become an impossibility?
Communications addressed to the Société d’Encouragement pour l’Industrie Nationale, Paris, describe a method for preventing the deposit of soot in chimneys; but as yet no details are published: also an apparatus for stopping runaway horses (in harness), by completely closing the winkers; and a way to deaden the blows of a hammer moved by machinery. In this case, the anvil is supported on a float in a reservoir of water. Another subject is a tramway car in which compressed air is the motive-power, as proved during some months on the line between Courbevoie and Puteaux, and the Round Point in the Champs-Elysées. This car has room for thirty passengers, is served by a conductor, and a mechanician who has entire charge of the machinery, which with a number of iron tubes is all placed between the wheels, under the floor, where it occasions no inconvenience to any one. A powerful air-pump at the starting station, forces air enough into the iron tubes for the journey to and fro, and the car travels smoothly and without noise or smoke, and can be stopped and started more readily than a horse-car. Mr Mékarski, the inventor of this car, has been thanked by the Société for having solved the problem of a locomotive which can be used with safety in crowded streets. Of course there are appliances for regulating the pressure of the air, and for preventing the deposit of hoar-frost in the tubes, consequent on rapid expansion of air; but for a description of these and other particulars we must refer to the Bulletin published by the Society.
Mr Coret has invented what he calls a self-acting thermo-signal which by ringing a bell makes known to all within hearing when an axle or any other part of an engine is over-heated. It is a small brass cylinder, containing a system of flexible metal disks, and a dilatable liquid, which is to be fixed to the part liable to over-heating. While all goes well the instrument makes no sign; but as the temperature rises the liquid dilates, forces out a small metal pin at the end of the cylinder, which, as the wheel revolves, strikes a bell, and thereby warns the attendants. Thus the necessity for constantly watching an indicator is avoided.
Other subjects brought before the same Society are—A description of a chimney which does not occasion loss of heat, by Mr Toulet, 38 Avenue de l’Observatoire, Paris—Specimens of harmless colours which may be used with varnish, oil, or water, and are described as durable and remarkably brilliant. They are available for many purposes of decoration, but are specially intended, as they contain no poisonous element, for the colouring of children’s toys. These new colours are derived from the substances known to chemists as eosin and fluorescin—And certain manufacturers who have carefully studied the material give an account of the capabilities of jute, from which we gather that by proper preparation of the yarns, remarkable effects of colour, of mottling, of light and shade, and also a velvety appearance can be produced. The process is described as very simple and moderate in cost; so that applications of jute to decorative purposes hitherto not thought of may ere long become available.
It has been found by experiment that aniline black can be made to yield different colours: treated in one way it is a light violet, in another way it is a bluish pink, and in a third way it becomes blue.
Pure butter, as is stated in the Journal of the Chemical Society, contains from ninety to ninety-eight per cent. of pure butter fat and a small quantity of water. Its colour should be from yellowish white to reddish yellow, but this depends on the kind of fodder given to the cows, and may be produced by means of beetroot or other plants possessed of colouring properties. The colouring matter may be detected by treating the butter with strong alcohol. The melting-point of pure butter is from thirty to thirty-seven degrees, while artificial butter melts at from twenty-seven to thirty-one degrees. Substances used to increase the bulk and weight of butter are chalk, gypsum, oxide of zinc, starch, and so forth. These neither improve its flavour nor its wholesomeness. The agreeable smell of pure butter, with a slight suggestion of milk, is not easy to imitate by artificial means.
Now that chemists can avail themselves of the spectroscope in their researches, falsifications have but little chance of escaping detection. We learn from the same Journal that the colouring matters generally used in the adulteration of wine are—fuchsine, the preparations termed caramels, ammoniacal cochineal, sulphindigotic acid, logwood, the lichen reds, rosaniline, bilberries, cherries, mallows, and the berries of the privet. Most if not all of these matters can be precipitated by chemical treatment, or they may be detected by dialysis. If a cube of gelatine less than an inch square be placed in the wine under experiment, it will be found, after twenty-four or forty-eight hours, stained all through, if artificial colouring matters are present; but if the wine is quite pure, then the natural colouring matter will not have penetrated deeper into the gelatine than one-eighth of an inch. It is worth notice that the natural colour soaks in slowly; the artificial colour quickly.
The Comptes Rendus of the Académie des Sciences, Paris, give an account of a patient who, through entire closure of the esophagus or gullet, could get neither food nor liquid into his stomach, and had to undergo the operation of gastrotomy. Through the opening thus made the operator passed different substances and took note of the time they remained in the stomach. Starch, fat, and flesh disappear in from three to four hours; milk is digested in an hour and a half or two hours, and alcohol and water are absorbed in from thirty-five to forty-five minutes. One day a small quantity of pure gastric juice was taken from the stomach for experiment: it is described as colourless, viscid, yet easily filterable, having little odour, and not putrefying spontaneously. The acidity of the gastric juice varies but slightly whether mixed with food or not, the mean being 1.7 gram of hydrochloric acid to one thousand grams of liquid. ‘The quantity of liquid,’ we are informed, ‘found in the stomach has no influence on its acidity; the latter is almost invariable whether the stomach be nearly empty or very full. Wine and alcohol increase the acidity, while cane-sugar diminishes it. If acid or alkaline liquids are injected into the stomach, the gastric juice reassumes its normal acidity in about one hour. It is more acid during digestion than when digestion is not going on, and the acidity increases towards the end of the process. Since the stomach is generally empty at the end of four hours, and hunger does not supervene till about six hours after a meal, it would seem that hunger does not result solely from emptiness of the stomach.’ This last remark is not in accordance with the opinions of other physiologists; but we venture to suggest that in common with the limbs, the stomach needs rest, and finds it in the two hours of quiet above mentioned. We would further remark, that the theory that sugar does not create acid in the stomach is contrary to all ordinary medical teaching, and even of daily experience.
A surgeon in a provincial town in Scotland has achieved a remarkable operation. He cut out from the neck of a patient a diseased portion of the larynx, and inserted an artificial larynx through which the man can speak articulately. This is one of the triumphs of surgery.
We mentioned some time ago that certain practitioners in the United States had succeeded in removing tumours by the application of a current of electricity. Recently the same method has been employed, and with the same success, for the removal of those blemishes from the skin popularly described as ‘port-wine stains,’ and other excrescences. Care is required in regulating the strength and duration of the current according to the nature of the case; if this be insured, the operation can hardly fail of a successful result. Particulars of cases and their treatment are published in the New York Medical Journal.