Professor Cohn, writing from Breslau to Nature, calls attention to the circumstance that just two hundred years ago there was made in the Netherlands a scientific discovery of the greatest importance. In the year 1683, Leeuwenhoek gave notice to our Royal Society that by the aid of his microscope he had detected in the white substance adhering to his teeth ‘very little animals moving in a very lively fashion.’ ‘These,’ says Professor Cohn, ‘were the first bacteria which the human eye ever saw.’ The descriptions and drawings given by this first observer are so correct, that even in these days, when the Germ theory of disease has brought forward so many workers in the same field, armed with much improved appliances, the organisms drawn by the hand of Leeuwenhoek can be easily recognised and compared with their fellows of to-day. These drawings have indeed never been surpassed till within the last ten years, a fact which speaks volumes for their accuracy and value.
The buildings occupied by the International Fisheries Exhibition at South Kensington are, in 1884, to be devoted to a no less important object, albeit it is not likely to be so popular with the masses. This Exhibition will deal with matters relating to Health and Education. It will include the food-resources of the world; the best means of cooking that food; the costumes of the world, and their bearing upon health; the sanitary construction of dwellings; and many other things that every one ought to know about, but which very few study. With the Prince of Wales as President, assisted by a Council including the names of Sir Cunliffe Owen and Mr Birkbeck, the success of the scheme ought to be assured.
In Cannon Street, London, an experimental section of roadway of a novel kind has lately been laid down. It is the invention of Mr H. F. Williams, an engineer of San Francisco, where the system has been most successfully employed for the past seven years. Indeed, the roads so prepared are said to be as good as when first laid down, allowing for a reasonable amount of wear and tear. The process is as follows. First of all is provided a good dry concrete foundation; upon this are laid blocks of wood, grain-end uppermost, measuring eight inches by four, with a thickness of an inch and a half. Each block, before being placed in position, is dipped halfway into a boiling mixture of asphalt and Trinidad bitumen; this glues the blocks to the foundation and to one another, at the same time leaving a narrow space all round the upper half of each piece of wood. This space is afterwards filled in with boiling asphalt. Above all is spread a half-inch coating of asphalt mixed with coarse grit, the object of which is to prevent that dangerous slipperiness that is common to asphalt roadways in moist states of the atmosphere.
At Brooklyn, the sanitary authorities seem to have a very sensible method of dealing with milk-dealers in the matter of adulteration. They invited the dealers to meet in the Common Council Chamber, when it was explained to them by an expert how they could determine by various tests whether the milk purchased from the farms is of the required standard. At the conclusion of this conference, it was hinted that the licenses of such dealers as were thenceforward detected in selling adulterated milk would be peremptorily revoked.
At the end of December last, the first of four large silos on Lord Tollemache’s estate in Cheshire was opened in the presence of a large number of farmers and scientific agriculturists. It had been filled with dry grass, chopped into inch-lengths by a chaff-cutter, and pressed down with a weight equal to fifty-six pounds on the square foot. The appearance of the ensilage was that of dark-brown moss, having a pleasant aroma; but, as in other experiments of the kind, the top layer was mouldy and spoiled. Lord Tollemache stated that he found that animals did not seem to care for the fodder when first offered them, but that they afterwards ate it with evident relish. Several samples of ensilage were exhibited at the late Cattle-show in London, and it is noteworthy that almost without exception the pampered show-animals, when a handful was offered them by way of experiment, took the food greedily. On Mr C. Mackenzie’s farm of Portmore, in Peeblesshire, a silo was opened in December, the contents of which—pressed down while in a moist condition—were found to be excellently suited for feeding purposes.
It is worthy of notice that the past year brought with it the fiftieth anniversary of the lucifer-match, which was first made in this kingdom by John Walker of Stockton-on-Tees in 1833. The same year, a factory was started at Vienna; and very soon works of a similar character sprang up all over the world. In 1847, a most important improvement was made in substituting the red amorphous phosphorus for the more common variety. This modification put an end to that terrible disease, phosphorus necrosis, which attacked the unfortunate matchmakers. The strong agitation which this disease gave rise to against the employment of phosphorus, naturally directed the attention of experimenters to other means of striking a light; and although phosphorus in its harmless amorphous form still holds its own, it is probable that its presence in lucifer-matches will some day be dispensed with. We need hardly remind our readers that the universal adoption of the electric light would greatly curtail the use of matches, for that form of illumination does not require an initial spark to set it aglow.
Some artillery officers in Switzerland have been putting their snow-clad mountain flanks to a curious experimental use, for they have been employing one of them as a gigantic target for their missiles. A space on this snow-covered ground measuring two hundred and thirty feet by ninety-eight feet—which would represent the area occupied by a battalion of infantry in double column—was carefully marked out, its centre being occupied by flags. At a distance of about a mile, the artillery opened fire upon this mapped-out space until they had expended three hundred shots. The ground was then examined; and the pits in the snow when counted showed that seventy-eight per cent. of the shots had entered the inclosure. Had a veritable battalion occupied the ground, there would have been few, if any survivors.
In another experiment, snow was employed as a means of defence against artillery. A wall sixteen and a half feet long, and five feet high, was built of snow having various thicknesses, but backed by half-inch wooden planking. This wall was divided into three sections, having a thickness respectively of four and a half feet, three feet, and twenty inches. Against the thickest section, twelve shots were fired from various distances; but in no case was penetration effected. In the three-foot section, shots pierced the snow as far as the woodwork, where they were stopped. In the twenty-inch section, all the shots fired went completely through the wall. It would seem from these experiments that snow, when available, can be made a valuable means of defence. But, unfortunately, in the published account of the experiments, the calibre of the guns employed is not given; we should, however, assume them to be field-artillery of a very light type.
A new use for the ubiquitous dynamo-electric machine is reported from Saxony, and one which seems to fulfil a most useful purpose—namely, the ventilation of mines. At the Carola pits, Messrs Siemens and Halske, the German electricians, have inaugurated this new system. At the pit bank, a dynamo is stationed, which is coupled up by shafting with the engine. By means of copper conductors, this machine is connected with another dynamo, two thousand five hundred feet away in the depths of the mine. This latter is connected with a powerful centrifugal fan. The cost of working these combined machines is six shillings and threepence per day, which means threepence for every million cubic feet of air delivered.
A new employment for the electric light has been found in Bavaria, where a Committee has reported upon its use as a head-light for locomotive engines. The colour and form of signals can be distinguished by the engine-driver on a cloudy night at a distance of eight hundred feet. The light burns steadily, and is not affected by the motion of the engine; but a special form of arc-lamp is employed, the invention of H. Sedlaczek of Vienna. The lamp is so constructed that it moves automatically when the engine traverses a curve, so as to light the track far in advance. The dynamo is placed just behind the funnel, and is easily connected with the moving parts of the machinery by suitable gearing.