The hot weather last summer affected even the herring fishery. The fishermen off the Scotch coast had been supplied with sea thermometers by the Scottish Meteorological Society, and they found that during one week, when the sea water showed a temperature of 58 deg. to 59 deg., no fish were caught. But when the temperature fell to 55 deg. the herring were caught in great abundance. Indeed, they flocked to the land in such numbers that many nets were taken to the bottom with their weight, and the fishermen lost considerable sums from this odd mishap. The action of the Meteorological has produced important results. The entirely new discovery has been made that the herring love cold water, and in seasons when the temperature of the sea water rises, they keep away from the land, in deeper water, between the fifteen to eighteen fathoms for which the nets are calculated. The colder the weather the greater is the take of fish; 1875, a year when the water was considerably and continuously warmer than 1874, having been a poor year, while the latter was a better one. This action of the fish makes it probable that it likes a given range of temperature, neither too high nor too low. In cold water this belt of agreeable temperature is found nearer the sun-warmed surface, and the fish creep inshore. Many singular facts relating to this fishery are known. If a thunderstorm occurs, the fishermen expect a good catch on that day, but the next day they will get none except in deep water, and the supposition is that the fish are leaving the land. The herring has a strong sense of locality, always returning to the same ground. Experienced dealers can tell by inspection in just what sea or loch a given lot of fish were caught.
NATURAL GAS IN FURNACES.
A paper describing the use of natural gas in the puddling furnaces at Leechburg, Pa., was presented by Mr. A. L. Holley to the American Institute of Mining Engineers. This well is about twenty miles northeast of Pittsburg, on one of the side tributaries of the Alleghany river. It had been drilled in search of oil to a depth of 1,250 feet in 1871, but none was found. A great flow of gas was developed, however, accompanied by a slight spray of salt water, and this has continued with little or no diminution to the present time. The gas in its escape has been discharged through a five-inch pipe, and at a pressure of from sixty to eighty pounds per square inch. The rolling mill of Messrs. Roger & Burchfield is on the opposite side of the river, and it has been for some years devoted to the production of fine grades of sheet iron from charcoal pig metal, by puddling and in knobbling fires. The usual weekly product of the mill has been thirty tons of No. 3 tin plates and fifty tons of No. 24 to twenty-eight sheets.
The well was bought by this firm for $1,000, and the gas is led across the river, a distance of 500 feet, through a three-inch pipe. It is distributed through half-inch pipes, and at a pressure of about forty-five pounds per square inch, to several of the furnaces. No essential alteration in any of the furnaces has been found necessary in the use of the gas fuel, except to brick up the fire bridge and to put in the gas and air pipes. The old grate used for coal is loosely covered with bricks and cinder, so that a slight percolation of air may take place through them. The gas is admitted through a half-inch pipe, and blows toward the fire-bridge through eighteen or twenty one-eighth inch jets. The air is blown in, at about 2 lbs. pressure, through two one and one-eighth-inch jets, obliquely down upon the centre of the hearth, and a very perfect combustion is obtained. A great improvement is effected in the quality of the product of the puddling furnaces by the combined action of the gas and air blast. The air is blown in during the melting, but it is then shut off until the boiling begins. It is then turned on full, and a violent boiling action is maintained without any rabbling. Many advantages result from the use of this fuel. The product of the mill has increased about thirty per cent., from sixty to seventy tons of coal are saved daily, besides the labor necessary to fire with it, and a poorer quality of iron can be used in making the tin plate. Thus the iron now used is credited to the furnace at $45 per ton, while charcoal blooms have cost $80. These are certainly enormous advantages, and though every mill cannot have a permanent gas well, it must be more economical to produce such results by making coal into gas than to continue using it in the solid form. The gas at Leechburg is used in fourteen furnaces and under seven boilers. Its composition is carbonic acid, 0.35; carbonic oxide, 0.26; illuminating hydrocarbons, 0.56; hydrogen, 4.79; marsh gas, C H4, 89.65; ethyl hydride, C2 H6, 4.39; specific gravity, 0.558. This analysis shows about 57 per cent. of carbon and 42 per cent. of hydrogen. If the well discharges one million cubic feet of gas daily, it would weigh about sixty tons, yielding thirty-nine tons of carbon. Mr. Holley calculates that it equals about 150 tons of bituminous coal, such as is found in the Pittsburg region.
SOUTH CAROLINA PHOSPHATES.
In England the favorite source of phosphates of lime is the "Cambridge coprolites." These are small, hard, gray nodules, obtained by washing a stratum, of about one foot in thickness, lying in the upper greensand formation in Cambridgeshire. Similar coprolites are found and mined in other districts of England, but they are of inferior quality, containing more oxide of iron and alumina. These give the tribasic phosphate of lime, which results from the application of sulphuric acid to the nodules, a tendency to "go back" to the insoluble condition. French nodules are of inferior quality from another cause. They contain very much silica, sometimes even forty per cent. The Cambridge coprolites are so much esteemed that buyers of artificial manure often stipulate that it shall be made from them. As a consequence the privilege of mining the ground is costly, sometimes as much as $1,500 an acre being paid. The yield is about three hundred tons to the acre. An English chemist reports that the South Carolina phosphate, made in factories situated in and near Charleston, ranks next in value to this Cambridge product. It contains 54 per cent. of tribasic phosphate of lime, 14 per cent. of carbonate of lime, 3-1/2 per cent. of iron oxide and alumina, 2-1/2 per cent. of fluoride of calcium, and 15 per cent. of silica. It consists of bone fragments derived from animal species which are now extinct. These bones have accumulated in old river beds, and the mining operations are compelled to follow the sinuosities of these streams. Though a supply derived from such sources is necessarily limited, the quantity known to be available is very great, and has been estimated to last a century with a yearly extraction of 50,000 tons. In addition to the river phosphate is a lighter deposit, occurring in a stratum of sand and clay about two feet thick; but this is not so valuable, though it is softer and easier ground. The river deposit is nearly black, and when ground makes a very dark powder. It is a great favorite, and in some respects the finest natural source of phosphatic manure in the world.
RARE METALS FROM OLD COINS.
The operations of the Government assay office in Frankfort during the last year have developed the fact that gold, platinum, palladium, and selenium are found in old silver coins and also in ores which were formerly supposed to be nearly pure sulphides and oxides of lead and silver. From 400,000 pounds of silver and 5,000 pounds of gold were obtained twelve pounds of platinum, two pounds of palladium, and several pounds of selenium. To obtain these the gold is first precipitated from the solution by ferrous chloride, all the other metals by iron turnings. The precipitate is first submitted to the action of ferric chloride to dissolve the copper, and the residue is fused with charcoal and soda to separate the selenium. The regulus from this operation is dissolved, and a compound of selenium and palladium, or of these with platinum, is obtained. They are composed of equal atoms of the two metals and form hard brilliant plates. The presence of these metals in coins is less remarkable than in such ores as those of Commern and Mechernich on the west bank of the Rhine. These ores occur as small granules of galena in a soft sandstone, their origin being still a mooted point. The ore yields a very soft and pure lead, though the presence of pyrite prevents the manufacture of the virgin lead used in making the best brands of white paint.
A FRENCH MOUNTAIN WEATHER STATION.
The French government has placed on the top of the Puy de Dome a meteorological observatory, which, as that is the highest land in France, answers to our stations on Mt. Washington and Pike's Peak. It is, however, constructed in a style very different from those somewhat forbidding abodes. At the top is an observatory tower, placed on a platform, and upon this is placed the anemometer, especially constructed to withstand the force of the storms. Within the tower is a well hole fifty feet deep, which leads to a tunnel more than a hundred feet long, at the end of which is placed the keeper's house. This is a massive building, situated a short distance from the top, where it is partly protected by rocks. The whole work cost $45,000, and $20,000 more will be spent in supplying it with apparatus.