RESULTS OF METEOROLOGICAL OBSERVATIONS MADE AT THE
KEW OBSERVATORY.

* To obtain the Barometric pressure at the sea-level these numbers must be increased by ⚫037 inch.

1.361

HOURLY MOVEMENT OF THE WIND (IN MILES), AS RECORDED BY ROBINSON'S ANEMOMETER.-JUNE, 1867.

8 9 10 11 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 13 14 15

558

99266

1022102724264O2

12 12 14 11 8 11 10 12 11 10

8 10 12 11 11 15 12

201 142 190 211 424 423 306 273 202 155 144 162 150 176 227 161 131 147 154 229 198 135 142 261 296 315 247 185 92121 8.6

PROGRESS OF INVENTION.

ECONOMIC PRODUCTION OF FORMIC ETHER, ON THE LARGE SCALE.— The peculiar odour of the peach, possessed by this compound, has recently given to it an importance that renders any simplification or diminution of expense during its manufacture a matter of interest. It may be very conveniently made by placing a mixture containing twenty-nine parts, by weight, peroxide of manganese, and nine parts starch in an alembic, and sprinkling it with a mixture formed with twenty-eight parts sulphuric acid, five parts water, and fifteen parts alcohol, and, after agitation, closing the alembic. Distillation takes place generally without the application of heat; the products being, first, alcohol, then nearly pure formic ether, and, finally, formic acid. Before sprinkling with the alcoholic mixture, the latter should be cooled, or the action may be far too energetic.

IMPROVEMENT IN THE MANUFACTURE OF STEEL.-In the old mode of forming steel all the carbon is removed from the cast iron, malleable iron being formed; and steel is made from this malleable iron by the addition of the proper amount of carbon. By the Bessemer process only enough carbon is removed from the cast iron to change it to steel; and the carbon is removed by the introduction of an abundance of atmospheric air into the cast iron in a state of fusion. The oxygen of the air burns the carbon. It might be supposed that any substance capable of affording oxygen, introduced into the fused cast iron, would answer instead of atmospheric air; and therefore the use of substances, such as nitrate of soda, etc., capable of furnishing large quantities of oxygen, was very soon attempted. But it was found that the very property possessed by these compounds of affording oxygen, caused them to rapidly destroy the converter-a vessel in which the change from cast iron to steel was effected. Not only was the carbon of cast iron, but the metal of which the converter was formed, burned. This was, of course, fatal to the employment of these salts as a source of oxygen. The difficulty was, however, not insuperable, and it has since been overcome. The converter is lined with a refractory material, and the nitrate is placed in pockets formed in this material. The cast iron is brought in contact with the nitrate, by means of a rapid rotation imparted to the converter: and the centrifugal force thus generated throws the fused cast iron into violent collision, and therefore complete contact with, the salt.

NEW BREECH-LOADING GUN.-A safe and very simple breechloading gun has been recently invented in France. The gases generated by the explosion are prevented from escaping at the breech by the application of the principle used by Bramah to render the pistons of hydraulic presses water-tight, however great the pressure. Attached to the screw that forms the breech of the gun, is a thimble of soft copper which protrudes into the barrel, and when the gun is fired its sides are expanded by the gases in all directions, so that no gas or vapour can escape between it and the barrel. There

is no trigger, and therefore it is impossible that the gun can go off by accident. The needle which ignites the explosive compound in front of the powder, passes into the screw which forms the breech, being kept back in its normal position by a spiral spring: it abuts against a thin elastic plate that closes the aperture in the screw, and does not project beyond the general surface. When the gun is to be discharged, the thumb of the right hand is pressed on the elastic plate. This forces in the needle, and ignites the detonating compound.

IMPROVEMENTS IN GALVANIC BATTERIES.-If the nitric acid in the Bunsen battery is replaced by an aqueous solution of picric acid, the evolution of disagreeable and unwholesome gases will be prevented, while the efficiency of the battery will not be injuriously impaired. The dilute sulphuric acid may be replaced by a solution of sea salt. The addition of picric acid also to a battery containing but one fluid greatly improves its action. The resistance to the current caused by the porous vessel of a Daniels battery is removed by a slight modification of its details. Within the outer vessel, which may be made of glass or porcelain, is placed a cylinder of copper much smaller than the outer vessel, but having attached to its lower end a disc of copper that just fits on the bottom of the onter vessel. Between the latter and the copper cylinder is the diaphragm, a cylinder of glass or ordinary porcelain, having on the outside, at the distance of one-third of its height from its lower extremity, small projections for supporting a cylinder of zinc. This battery is charged by placing siliceous sand in the interior of the diaphragm, and on this sand crystals of sulphate of copper; then pouring a solution containing about five per cent. sulphuric acid gradually into the outer vessel, until it reaches the crystals of sulphate. The electricity passes directly from the zinc to the copper disc, without being retarded by passing through a porous vessel. If the exterior vessel is glass, any deposit of copper on the zinc can be perceived at once and prevented. The greater the number of times per day the battery is to be used, the more permeable ought to be the sand, that the sulphate may be supplied with sufficient rapidity. The stratum of dissolved sulphate must never be allowed to rise high enough to come in contact with the zinc; if it is becoming too high, sand is to be added, or some of the liquid within the diaphragm is to be removed with a syphon--which will cause the sulphate to be driven back, on account of the greater height of the liquid in the external vessel.

IMPROVEMENTS IN PLATING AND GILDING.-The danger to the workman from contact with mercury is entirely prevented in gilding and plating, by dipping the article to be gilt or plated in the solution of a basic salt of mercury while in connection with the positive pole of a galvanic battery, and, when it is covered with mercury, immersing it in a strong solution of the gold or silver salt; then plunging it a second time in the mercurial solution, and afterwards evaporating the mercury in a furnace. Or the article which is to be gilt may be dipped into sodium amalgam, the surface of which has been covered with a little water, the portions which are not to be

gilt having been protected with varnish; after which an amalgam of gold is to be applied, and the mercury is to be evaporated by heat. Amalgam containing only the one two-hundredth part sodium will be sufficiently active to amalgamate tarnished metals, or iron and platinum, which, in ordinary circumstances, have no tendency to become wetted with mercury.

IMPROVEMENT IN HOROLOGICAL MACHINES.-It is scarcely too much to assert that the rate of a well-constructed clock or watch would be invariable, but for alterations of temperature. With an increase of temperature the pendulum is lengthened, and consequently its vibration is rendered slower; with a decrease, the contrary takes place. Analogous effects are produced by changes of temperature on watches and chronometers: and as, during summer and winter, night and day, the temperature of the air is perpetually changing, it may well be supposed that without the adoption of some means for counteracting the effects of changes of temperature, the rate of clocks, watches, and chronometers would be subject to perpetual alteration; and such is the case with ordinary horological instruments. But ingenious means have been devised for compensating the changes produced by temperature. These means, however, are subject to two considerable drawbacks: they are more or less complicated and therefore expensive, and they are rarely as perfect in their action as might reasonably be desired. A new mode of compensation for clocks, watches, and chronometers has been invented by M. Menon, which is extremely simple, and therefore inexpensive; and very effective, because calculated exactly to counterbalance the effect of changes of temperature, by bringing into opposite actions two precisely equal forces. In the compensations hitherto in use, the expansions and contractions of different substances are made to counteract each other; and thus, from the difficulty of making them exactly equal in their operations, a serious source of error is introduced. With the gridiron pendulum, for example, the rods which raise the bob of the pendulum may not expand to the same degree as the rods of a different metal which lower it and the raising and lowering may thus not be equal-that is, the length of the pendulum may vary. With the mercurial pendulum, the centre of gravity of the mercury may not be altered in position so as exactly to counterbalance the alteration in the length of the pendulum rod produced by change of temperature. In M. Menon's contrivance, the two portions of the compensation are exactly the same in every respect, and therefore when their expansions or contractions are made to neutralize each other, the effect must be zero-that is, the length of the pendulum must remain unchanged. In the construction of a compensation pendulum on this principle, two rods of the same metal, and of the same dimensions, are used; the pendulum is attached to one, and the other is coiled up-merely for convenience, the alterations produced by change of temperature being exactly the same whether the rod is in the form of a right or curved line. The rod, in the form of a spiral, is used to suspend the bob of the pendulum, or the pendulum itself. For this purpose, one end of it is fixed to the bob, which