The delegates of the French Chambers of Commerce who accompanied M. de Lesseps during the late survey of the Panama Canal works, have now returned with hopeful tales of the ultimate success of the grand project for uniting the Atlantic and Pacific Oceans. Briefly put, the matter stands thus: let money be supplied, and the work can be brought to a glorious termination. M. de Lesseps affirms that the canal can be opened for traffic as soon as 1889; and he points to the circumstance that all contracts expire in 1888. But contractors are but mortal, and it is believed by experts that the hard Culebra rocks, which present the most formidable obstacle to the prosecution of the work, cannot be cut through in less than five years. These rocks are more than a mile in length, and in some spots they rise to a height of more than one hundred and fifty feet above the canal level.
In a recent article on ‘The National Egg-supply,’ a contemporary gives some interesting particulars regarding the productiveness of different kinds of fowls. The laying power of each hen is said to be on an average one hundred eggs per annum. This seems a small average. Some fowls will lay as many as two hundred and twenty per annum, but the larger proportion yield not more than from sixty-five to one hundred and twenty per annum. Care and proper food have much to do with productiveness, as all keepers of fowls know well. A large portion of our egg-supply comes from Ireland, where the birds are not nearly so well tended as they are in England and Scotland. A score of Irish eggs selected at random from a large crate weighed a little under two pounds. The eggs from good Dorkings will weigh six ounces more than this. The eggs from Spanish fowls weigh two pounds fourteen ounces per score; while those from Leghorns weigh as much as three pounds for the same quantity. The total cost of our annual egg-supply is calculated to be nearly seven millions sterling.
Mr W. K. Brooks, of the John Hopkins University of America, has put forward a new observation regarding oyster spat, which may account for the failure of the fisheries in many parts of this country. He remarks that the young oyster as it settles upon the bottom of the sea is in some localities so covered with sediment that it is killed at a very early stage of existence. He holds that the tender oyster should find a resting-place which must be clean as well as free from destructive pests. He recommends the employment of floating frames furnished with a bottom of galvanised wire-netting for the reception of the fry. Under such conditions, it is found that oysters grow with wonderful rapidity.
Anglers know well that the voracious pike is a fish most tenacious of life, and that hours after he has lain in the fishing-creel apparently dead, he is quite capable of giving a snap with his sharp teeth. But few are aware how long a pike will live out of his proper element. A Paris fishmonger recently received a quantity of fish from Rotterdam which were packed in ice. Among these was a pike over two feet long, which, on unpacking, was seen slightly to move its gills. The fish was placed in fresh water, with the result that in a few hours it was fully alive and very active. This fish, as far as can be learnt, was actually out of the water for three days, during which time it travelled nearly three hundred miles. It is now in the Trocadero Aquarium, and seems to have fully recovered from its curious experience.
The Sanitary Record informs metropolitan householders that their peace is threatened with a new danger. A London resident found that each time the water was turned on to his house, a plentiful supply of coal-gas was delivered gratis at the same time and through the same pipes. The explanation of the matter is as follows: in the particular street where this strange thing happened, the soil round the water main is completely saturated with gas from leaky pipes. When the water is turned off, there is a vacuum formed in the main, and gas is sucked in through imperfect joints, to be delivered to the unfortunate residents directly the water is again turned on. The matter can of course be easily remedied; but the serious lesson taught by the incident is that gas can find its way to water-pipes, and that sewer-gas may as easily do so as coal-gas.
The last application of rock-oil is a petroleum engine, which we saw working lately in London. In general appearance, it is like a gas engine; but it has a tank fixed above the cylinder which contains a supply of petroleum. This liquid is conveyed by a small pipe and pump to the cylinder at the rate of about four drops per stroke of the piston rod. It is ignited by a spirit-lamp after having been mingled with sufficient air to form an explosive mixture. The working cost of the engine is calculated at three-halfpence per horse-power per hour for petroleum, and one-sixth of that sum for lubricating. The engine will be valuable where gas is not to be obtained and where steam is inadmissible.
Mr William Anderson lately delivered an interesting lecture before the Royal Institution ‘On New Applications of the Mechanical Properties of Cork to the Arts.’ He showed that cork was unique among solid substances in being capable of cubical compression both from forces applied in opposite directions and from pressure from all sides. This is shown when cork is immersed in water and is subjected to hydraulic pressure. The phenomenon in question is due to the peculiar cellular structure of the material, which causes it to behave more like a gas when under pressure than like a solid. Mr Anderson proposes to use cork instead of air in the air-vessels of water-raising machinery, and he showed by experiment how well fitted it was for doing this duty. He also proposes to use it in connection with gun-carriages in the following way: the carriage is to be furnished with hydraulic compressors in the customary manner, but the water in the cylinders is to be driven by the recoil of the gun into a vessel filled with cork. This will represent a store of energy which will run the gun out again when loaded, by the aid of a tap which will liberate the water from the compressed cork. The lecture certainly exhibited cork in a new character, and called attention to many ways in which it can be used with advantage.
The nebula in the Pleiades, so strangely discovered by photography, although it was quite invisible to ordinary telescopic scrutiny, has now been detected by more than one observer. It is, however, as may be guessed, an extremely faint object. MM. Perrotin and Thollon, of the observatory at Nice, say that they have seen it, but admit at the same time that this was only because they knew from the Paris photograph that it existed.
The number of valuable substances which can be extracted from coal-tar is marvellous, and would surprise gas manufacturers of a generation ago, who gladly gave away the tar to any one who would take it. The last product of the black and ill-smelling fluid is a substance which has been named Saccharin, on account of its extreme sweetness, and the discovery is due to Professor Fahlberg. Saccharin is said to be two hundred and thirty times sweeter than the best cane-sugar. It has a great interest for the medical profession, for it can be used to render palatable the food of patients suffering from diabetes, and has been already adopted for this service in one of the Berlin hospitals. At present, the new sweetener costs forty shillings per pound. It has been ascertained by experiment that saccharin is innocuous; and we may feel sure that if its price can be reduced, it will become a formidable rival to sugar.
The chief of the United States Geological Survey, Major Powell, has discovered near California what he believes to be the oldest human habitations on the American continent. The mountains in the vicinity are covered with beds of lava, in which have been excavated square rooms, lined with a kind of cement made with lava. Although these rock-dwellers were of prehistoric time, their work shows traces of an advanced civilisation. Several articles of pottery have been found in these cave-dwellings, as well as a kind of cloth made of woven hair. Wrapped in such a cloth, which tumbled into dust when touched, there was found a small image resembling a man. No fewer than sixty groups of these villages in the lava have been found.