At a recent meeting of the Royal Society of Edinburgh, Dr A. B. Griffiths read a most instructive paper on ‘The Effect of Ferrous Sulphate in destroying the Spores of Parasitic Fungi.’ The value of this salt—the common ‘green vitriol’ of commerce—as a plant-food has long ago been established; but Dr Griffiths points out the important antiseptic property it possesses in destroying certain low forms of plant-life. As a preventive of potato disease, it is most effectual, although the spores of that fungus possess such vitality that they may be kept as dry dust for eight months without losing their power for mischief. Dr Griffiths also notes that in damp warm weather, the potato disease is actually encouraged by the use of potash manures. He advocates the treatment of manure with a weak solution of the iron salt before its application to the land. Wheat when treated with the sulphate is rendered proof against mildew.
A clever method of damascening metals by electrolysis is described in a French technical journal. The process consists of two distinct operations, and is based on the well-known fact, that when two copper plates are hung in a bath of sulphate of copper and connected with the opposite poles of a battery, a transfer of metal from one to the other will take place. In the case before us, a copper plate is covered with a thin layer of insulating material, as in the etching process, and this is drawn upon with an etching needle so as to lay bare the metal beneath. This is now submitted to the action of the electric current, so that the metal is eaten away to a certain depth in the exposed parts. The plate is next washed with acid, to remove all traces of oxide of copper in the bitten-in lines, and is then transferred to another bath by which metallic silver or nickel is deposited in the etched parts, with the result that the sunk lines are ultimately completely filled with the new metal. When the plate is relieved of its waxy coating and is polished, it is impossible to say whether or not the beautiful inlaid appearance has been produced by a mechanical process or by skilled handiwork.
Two remarkable finds of old coins have lately occurred—one at Milverton, a suburb of Leamington; and the other at Aberdeen. In the first case, some labourers were digging foundations, when they found a Roman amphora, which they immediately smashed to ascertain its contents. It contained nearly three hundred coins in silver and copper. These were of very early date, and in a state of excellent preservation. The Aberdeen treasure trove came to light in excavating Ross’s Court, one of the oldest parts of the city. Here the labourers found a bronze urn filled with a large number of silver coins. These coins also are well preserved. They are all English, and are mostly of the reigns of Edward I. and Edward II. Some of these coins are of extreme rarity, and the discovery has great antiquarian interest.
The largest installation of the electric light, worked from a central point, which this country has yet seen has been recently completed at the Paddington terminus of the Great Western Railway. The lights, which are equivalent to thirty thousand ordinary gas jets, are distributed between the Paddington passenger and goods stations, the ‘Royal Oak,’ and Westbourne Park Stations, the terminus hotel, and all the various offices, yards, and approaches to the railway Company’s premises. The district covers no fewer than sixty-seven acres of ground, and is one mile and a half long. The two Gordon dynamos which are used to generate the current weigh forty-five tons each, and give sufficient power to serve four thousand one hundred and fifteen Swan glow lamps, each of twenty-five candle-power; ninety-eight arc lamps, each of three thousand five hundred candle-power; and two of twelve thousand candle-power each. The current is kept on day and night, except for a few hours on Sunday morning, and each individual lamp is under separate control by a switch, so that it can be turned off and on just like a gas jet. Every detail has been well thought out, and the vast scheme is a success in every way. We understand that the contractors, the Telegraph Maintenance and Construction Company, have undertaken to supply the light at the same price as would have been charged for gas lamps giving the same light-value.
From a paper read by Mr C. Harding before the Royal Meteorological Society on ‘The Severe Weather of the Past Winter,’ we learn that the cold lately experienced has been of the most exceptional character. The persistency with which frost continued for long periods was quite remarkable. In south-west England, there was not a single week from October to the end of March in which the temperature did not fall below the freezing-point; and in one town in Hertfordshire, frost occurred on the grass on seventy-three consecutive nights. Since the formation of the London Skating Club, nearly sixty years ago, the past season has been the only one in which skating has been possible in each of the four months December to March. We therefore must note that we have just passed through an unusually severe season.
Fresh fruit from the antipodes, of which two large consignments have recently reached London, is now being daily sold to eager purchasers in the Australian fruit-market at the Indian and Colonial Exhibition. Grapes, apples, pears, and other fruits, in splendid condition, and with their flavour unaltered by their long separation from their parent stems, can now be conveyed by the shipload, packed in cool chambers, in the same way that meat is imported from the same distant lands. The success of the enterprise opens up a wide field of promise to those in temperate lands who have been dazzled by the reports of travellers as to the luscious nature of foreign fruits, which hitherto have been quite out of reach of stay-at-home Britons. We seem to be fast coming to the time when fairy tales will be considered tame and uninteresting, from being so far eclipsed by current events.
A correspondent of the Times notes a most important means of escape from suffocation by smoke, a fatality by which many lives are lost annually. He points out that if a handkerchief be placed beneath the pillow on retiring to rest so as to be within easy reach of the hand, it can, in case of an alarm of fire, be readily dipped in water and tied over the mouth and nostrils. As an amateur fireman, he has gone through the densest smoke protected in that manner, and he alleges that such a respirator will enable its wearer to breathe freely in an otherwise irrespirable atmosphere.
Professor Dewar lately exhibited at the Royal Institution, London, the apparatus he employs for the production of solid oxygen. If we refer to the physical text-books of only three or four years back, we find oxygen, hydrogen, and nitrogen described as permanent gases, for no one had ever produced either in any other form. At length all three had to give way before scientific research, and they were by special appliances reduced to the liquid state. Professor Dewar is the first experimenter who has taken the further step of producing one of these gases in a solid form. His method consists in allowing liquid oxygen to expand into a partial vacuum, when the great absorption of heat which accompanies the operation causes the liquid to assume a solid state. It is said to resemble snow in appearance, with a temperature greatly below the freezing-point of water. It is believed that a means of producing such a degree of cold will be of great service to experimental chemistry.
Mr W. Thomson, F.R.S.E., has devised a new process for determining the calorific power of fuel by direct combustion in oxygen, which promises to supersede, by reason of its greater accuracy, the methods hitherto in use. The process consists in placing a gramme of the coal or fuel to be tested in a platinum crucible covered with an inverted glass vessel. The whole arrangement is placed under water in a suitable receptacle; and the fuel, burnt in oxygen, burns away in a very few minutes, giving off much heated gas, which escapes through the water. The temperature of the water, compared with its temperature before the operation, gives the data upon which the heating power of the coal can be calculated. The question of heat-value in fuel is of course one of first importance to railway Companies and other large consumers of coal. It is, too, in a minor way of importance to householders, who often find, by painful experience, the little heat-value of the fuel which has been shot into their cellars. If coal-merchants were to furnish some guarantee based on a scientific test as above described, they would find it to their own profit, as well as to the advantage of their customers.
We do not hear very much in these days of mummy wheat and barley, but many people firmly believe that the seeds of both plants found with Egyptian mummies, and supposed to be three or four thousand years old, will sprout if put in the ground. A few years ago, such wheat was commonly sold as a curiosity; and we believe that many purchasers succeeded in raising a small crop from it. Professor Bentley, who has recently commenced a series of lectures on the Physiology of Plants, asserts most emphatically that no grains which with certainty have been identified as contemporaneous with the deposit of the mummified corpse, have ever come to life. In cases where the so-called mummy wheat has germinated, it has been introduced into the coffin shortly before, or at the time of discovery of the body. Professor Bentley does not name a limit to the time during which seeds retain their vitality, but he says that very few will germinate after being three years old.