The produce of gold for the month of February, 1870, being according to the Mineral Inspector's Report, as follows:

Mr. R. Brough Smith reports that the total quantity of gold raised in Victoria in 1869 was 1,544,757 ounces, and of this there were exported 1,340,838 ounces. The total imports into England of Australasian gold in 1869 were of the value of 7,892,7577. Since 1858 the imports have been as follows:

The increased returns of the last three years were due to the opening of new gold-fields in Queensland, South Australia, and New Zealand.

METALLURGY.

Mr. Spence, of Newton Heath, Manchester, has patented a new process of separating copper from ores. He takes the solution of chloride of copper as now obtained in extracting copper from ores (by the wet process) which contains iron in variable proportions, and generally contains free hydrochloric acid. This solution he places in large open vats, and in another vessel of cast iron, fitted with a revolving stirrer, he places a considerable quantity of the vat waste of the alkali manufacture, or the spent lime from the gas purifiers, and to this is added a solution of sulphate of ammonia, or chloride of ammonium. The vessel or still being closed, a jet of steam of from 20 to 30 lbs. pressure is blown into the mixture. Sulphide of ammonium distils over, and is conveyed by a pipe into the vat containing the metallic solution of copper and iron, by which sulphide of copper is precipitated, and the ammonia combines with the

liberated hydrochloric acid. The process is continued until all the copper is thrown down, which point is at once observed by sulphuretted hydrogen being evolved, when the process is stopped; for if continued, the ammonia would now neutralize the free acid, and the iron would then be precipitated. The sulphide of copper thus obtained is very nearly pure; it is washed and dried, and smelted into copper by any of the usual methods employed.

A new process of calcining tin and other ores has been adopted by Messrs. Oxland, F.C.S., and John Hocking. The ores are introduced into a revolving iron cylinder, 4 feet in diameter and 30 feet long, lined with fire bricks, and supported at an inclination of about inch per foot on three pairs of rollers, on which it is kept constantly revolving at a slow rate. The fire passes from the fireplace over a chamber into and through the tube. The ore having been first dried on iron plates in suitable flues, at the back of the calciner, is admitted in a steady stream into the higher end of the cylinder, and the slow revolving motion imparted to it causes the advance of the ore by its own gravitation, and it is discharged in a continuous stream into a chamber between the fire-place and the front of the tube. Great economy of fuel is said to be effected by this furnace. The heat from the fuel has to traverse more than double the distance over which it passes in Brunton's calciner before it escapes into the flues, and the tube presents nearly double the amount of heating surface. None of the working parts are exposed to the action of the fire. In working it is found to be economical both as regards fuel and labour.

Several patents have been taken out of late relating to the manufacture of iron and steel. Mr. Cowper, of Westminster, patents improvements in treating cast iron for the production of wrought iron and steel therefrom. By this process the purification of the cast iron is accomplished by a jet of superheated steam applied to a stream of the liquid iron as it flows from the blast furnace, so as to divide it up into small particles, and act upon them; the iron is received into a hot box, and transferred to a calcining furnace, in which it is kept hot whilst still exposed to an atmosphere of hot steam; such purified iron is mixed either hot or cold with liquid cast iron, and afterwards used as cast iron, or made into steel or wrought iron.

In the manufacture of steel Mr. Julius Baur, of New York, patents a process of alloying or combining metallic chromium with metallic iron, so that chromium in a metallic state shall be present in the finished product, which is said to impart valuable properties to it. This process is distinguishable from that secured by Mr. Robert Mushett for mixing oxide of chromium in the manufacture of steel.

Letters patent have also been granted to Mr. J. M. Stanley, of Sheffield, for improved modes of utilizing the heat given off during

the decarbonizing or converting process, the object of which is to economize the consumption of fuel, and reduce the cost of the metals.

There is also an invention whereby very superior iron and steel are said to be obtained by smelting titanic iron ore, Ilmenite, in a blast furnace, without the addition of any other metalliferous body; the alloy of iron thus obtained possesses a large percentage of carbon. Various methods are adopted to carry out this process. The inventor is Mr. T. S. Webb, of the Norton Iron Works.

11. PHYSICS.

LIGHT.-Spectrum analysis has been applied by Vogelsang and Geissler to the difficult question of determining the chemical nature of the fluid found enclosed, in minute quantity, in the cavities of certain quartz-crystals. Fragments of quartz were placed in a small retort, which was connected with an air-pump and exhausted; then, by the application of heat, the quartz decrepitated, and the evolved vapour was examined in a Geissler-tube. The presence of carbonic acid was thus abundantly proved, and this was confirmed by the turbidity which it produced in lime-water.

A great improvement in the spectroscope has been made by Mr. Browning, who calls his instrument the automatic spectroscope. It is furnished with a battery of six equilateral prisms of dense flint glass; all the prisms are joined together like a chain by their respective corners, the bases being in this manner linked together. This chain of prisms is then bent round so as to form a circle with the apices outwards; the centre of the base of each prism is attached to a radial rod. All these rods pass through a common centre. The prism nearest the collimator, i. e. the first prism of the train, is a fixture. The movement of the other prisms is then in the proportion of 1, 2, 3, 4, and 5, the last or 6th prism moving five times the amount of the second. All these motions are communicated by the revolution of the micrometer screw, which is used for measuring the position of the lines in the spectrum; and the amount of motion of each, and of the telescope, is so arranged that the prisms are automatically adjusted to the minimum angle of deviation for the ray under examination. It is easy to test the efficiency of the instrument in this respect. On taking the lens out of the eye-piece of the telescope, the whole field of view is found to be filled with the light of the colour of that portion of the spectrum which the observer wishes to examine; while in a spectroscope of the usual construction, at the extreme ends of the spectrum, just where the light is most required, only a lens-shaped line of light would be

found in the field of view. As a consequence of this peculiarity, the violet and deep-red ends of the spectrum are greatly elongated, or rather, much more of them can be seen than in an ordinary spectroscope, and the H lines, which are generally seen only with difficulty, come out in a marked manner.

Drs. Roscoe and Thorpe have recently communicated to the Royal Society the results of a series of determinations of the chemical intensity of total daylight, made in the autumn of 1867, on the flat plateau of the river Tagus, about 8 miles south-east of Lisbon, under a cloudless sky, with the object of ascertaining the relation existing between the solar altitude and the chemical intensity of the light. The experiments were made as follows:-1. The chemical action of total daylight was observed in the ordinary manner; 2. The chemical action of the diffused daylight was then observed, by throwing on to the exposed paper the shadow of a small, blackened, brass ball, placed at such a distance that its apparent diameter, seen from the position of the paper, was slightly larger than that of the sun's disk; 3. Observation No. 1 repeated; 4. Observation No. 2 repeated. Next, the means of observations 1 to 4 were taken. The sun's altitude was determined by a sextant and artificial horizon. One of the sets of 134 observations was made as nearly as possible every hour. It has been already pointed out, and proved by experiments made at Kew, that the mean chemical intensity of total daylight, for the hours equidistant from noon, is constant. The results of the present series of experiments prove that this conclusion holds good generally. One of the chief results arrived at is that, although the chemical intensity for the same altitude, at different places and at different times of the year, varies according to the varying transparency of the atmosphere, yet the relation, at the same place, between altitude and intensity, is always represented by a straight line.

A new and very ingenious graduating diaphragm for the microscope has been contrived by Mr. J. Zentmayer. This exceedingly ingenious arrangement is shown in the accompanying cuts, which are taken from photographs; Fig. 1 showing the apparatus with

gradually by a continuous change, and yet be made of rigid and unchangeable material, might seem at first sight to be an impossibility; but, after all, when the result is accomplished, as in this apparatus, we are surprised as much by the simplicity as by the ingenuity of the means employed. The woodcuts almost explain the apparatus of themselves; but we may say, in addition, that it consists of two cylinders or rollers with parallel axes and surfaces in contact, having similar conical grooves on their surfaces, and fine teeth cut at one end of each, which, gearing together, cause them to rotate in unison. There is, theoretically, an objection to a diaphragm of this construction, from the fact that its opening will not always be in the same plane-that is, the smallest cross-section of the space between the rollers will not always be equidistant from a plane at right angles to the line of sight and passing through the axes of the rollers. With the larger opening, this cross-section will be nearest to, and with the smaller, farther from, such a plane. In practice, however, this difference is so small as to be entirely unimportant, and may even, in some cases, be turned to advantage.

Experiments have been made at Toulon by M. F. Silvas to try to attach to life-buoys another floating body provided with phosphide of calcium, which, on becoming wet, gives off spontaneously combustible phosphuretted hydrogen, thus emitting light to guide the man, who might have fallen overboard and be in search of the life-buoy.

HEAT. Dr. Guy has arranged in series the different poisonous substances according to their melting and sublimation temperatures. The arrangement is as follows:-(1) Sublimates formed without any previous change of state of aggregation, and giving white vapours; under this head are brought bichloride of mercury, calomel, arsenious acid, and cantharidine. (2) Sublimates after previous fusion, and without leaving any residue-viz. oxalic acid. (3) Sublimates after previous fusion, leaving a carbonaceous residue -morphine and strychnine. (4) Fusion, change of colour, sublimation and deposition of carbonaceous residue, aconitine, atropine, delphine, veratrine, brucine, digitaline, picrotoxine, solanine. (5) Decrepitation; slow and partial sublimation; tartar emetic.

Professor Morren has instituted some experiments on the combustibility of diamonds, and the effect of a high temperature on these gems. The author, in a letter, first relates the following facts as having given rise to his experiments. A jeweller at Marseilles was requested to enamel afresh the gold bearings of two large diamonds of great value, used as shirt buttons. Instead of taking off the diamonds, always a delicate operation, the jeweller, who had frequently executed such work previously, decided to enamel the gold while the diamonds were left on their bearings. Not having