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In Birmingham it is made from the following mixture:

cwts.

qrs.

lbs.
French sand,
Carbonate of soda,

1
3

7
Lime,

7 Nitrate of soda,

1 Arsenious acid,

2

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The best qualities of this glass are at present produced in the Siemens furnace.

CUTTING GLASS WITH STEEL.

THE MAGIC DIAMOND.

The cutting of glass with steel has been demonstrated to be possible, provided its point is ground into the form of a common glazier's diamond. But while hard steel of this form will cut glass, it is difficult to bring a steel point to the required shape, and it also soon wears out and becomes worthless, until reground. Many efforts have been made to make a tool of steel that would compete at least approximately with the real diamond for this purpose. It has been discovered that a small cylindrical point of steel, when made to rotate upon glass in such a manner that its longitudinal axis shall make an angle of 45 degrees with the sur, face of the glass, approaches in effect so nearly to that of the real diamond that it is a very cheap and effective substitute.

HEAVY MODERN MACHINERY. A mass of metal of a ton weight was unknown before the Christian era. Now those in cast iron up to 150 tons, in wrought iron to 40 tons, and in steel or bronze to 25 tons, are made in any desired form, and turned or bored with the most perfect accuracy. Two years ago I saw the largest lathe in England, which swings 22 feet, and will take in a shaft 45 feet long. Six months ago I saw one in this country which swings 30 feet, and will take in a shaft of 50 feet. There are planers which will plane iron 50 feet in length; others of 18 feet in width; others of 14 feet in height, taking off metal shavings of two and a half inches in width and a quarter thick. — W. J. McAlpine.

NEWEST COLORING MATTERS.

A lecture has been given by Mr. W. H. Perkin, at the Royal Institution, “On the Newest Coloring Matters." Among the many interesting facts then put forward was the discovery of a beautiful blue color, by a German chemist, on treating rosaline with sulphuric acid. Unfortunately, it was not a “ fast color.” A dyer made many trials therewith, in the hope of turning it to account, but all in vain. He happened to mention his difficulty to a photographer, who, knowing that hyposulphite of sodium would fix a photograph, recommended the dyer to try that. The trial was made; when mixed with the hyposulphite, the blue became a beautiful green, and, better still, a “fast color.” This was the origin of that brilliant dye commonly known as “ Night green,” because of its remaining unmistakably green in appearance when seen by artificial light. Let it be remembered that nearly all the new colors are extracted in some way from coal tar; that the first was discovered not more than 13 years ago, and that the annual value now manufactured is 1,250,000 pounds, and it will be seen that in the industry created by these new products there is an admirable example of the results of scientific investigation. The best of it is that the field is inexhaustible; for many years to come it will yield a rich harvest of discoveries.

REFINING VEGETABLE OILS.

Mr. C. Michaud, of Honfleur, has discovered a new method of refining oil, which will probably eclipse all those in general use at the present day. This method has just been communicated by M. Chevallier to the Société d'Encouragement. While sulphuric acid is introduced into the oil in minute numerous streamlets, air is blown into the oil so as to produce

a great commotion in the liquid and to fill it with air-bubbles. The mucilage contained in the crude oil, being acted on by the acid, soon forms with the air a voluminous layer of scum at the surface, which is skimmed off as it forms. This insufflation of air is repeated several times in succession, and the scums cleared off every time until the oil is clarified. At this point of the operation it still retains free sulphuric acid. It is now run into a copper vessel, and steam is forced through it until the oil has reached a temperature of 100° C. The steam is then allowed to bubble through for half an hour or an hour longer. After the oil has cooled down some 20° or 30° C., which may be done artificially, it is run through an ordinary filter. Two large refineries have lately been put up on the “ Michaud” plan, and the oil produced by them is so pure, that the wick of a lamp burning it will not carbonize after many days' usage.

ON THE PENETRATION OF ARMOR-PLATES BY SHELLS WITH

HEAVY BURSTING CHARGES, FIRED OBLIQUELY. BY JOSEPH WHITWORTH, LL.D., F.R.S.

At the meeting of the British Association last year, Mr. Whitworth contributed a paper “On the Proper Form of Projectiles for Penetration through Water,” wherein he claimed for the flatfronted form of projectile made of his metal three points of superiority over the Palliser projectiles. First: Its power of penetrating armor-plates even when striking at extreme angles. Secondly: Its large internal capacity as a shell. Third: Its capability of passing undeflected through water, and of penetrating armor below the water line. He illustrated the penetrative power of long projectiles, with the flat front fired at extreme angles against iron plates, by the projectiles actually fired and the plates they penetrated. The gun from which all the projectiles were fired was a 3-pounder; it weighs 315 lbs., and the maximum diameter of its bore is 1.85 inches. The charge of powder used was 10 ounces, and the weight of the 6-inch diameter projectiles is 6 lbs. He considered he had established the superiority of the flat-fronted projectiles made of his metal, and that the Palliser projectiles fail to penetrate when striking at an angle, solely on account of the form of the head. The results obtained with the small calibre of the rifle closely agree with those of the 3-pounder gun. He had always found that what he could do with the smaller calibres could be reproduced in the larger sizes, and could be repeated on a proportionate scale with his

9-inch gun, or the 11-inch guns his firm are now engaged in constructing. The 9-inch guns weigh 15 tons each, and are capable of firing powder charges of 50 lbs. A 9-inch armor shell, 5 diameters long, weighs 535 lbs., and will contain a bursting charge of 25 lbs. These projectiles would pierce the side of a ship plated with armor at a distance of 2,000 yards, and at some depth below the water line. The 11-inch guns will weigh 27 tons, and will be capable of firing 90 lbs. powder charges. The 11-inch shells, 5 diameters long, will weigh 965 lbs., and will contain bursting charges of 45 lbs., and would pierce a side of the ship “ Hercules," plated with 9-inch armor, at a distance of 2,000 yards. He had named these long projectiles the “antiwar” sheil. Four guns of 12 inches bore have lately been put on board the “Monarch;” they weigh 25 tons each, and fire charges of 50 lbs. and 67 lbs., and projectiles of 600 lbs. weight; but the weight of these guns was in proportion to their bore; and if the material were the best that could be supplied, they ought to fire 117 lbs. of powder and projectiles 1,450 Ibs. weight.

LIFE OF AMERICAN VESSELS.

At the meeting of the American Association, at Salem, Professor E. B. Elliott, of Washington, gave a Life Table of American Sea-Going Sailing Vessels, derived from the career of 26,737 vessels, of which 4,165 were known to be extant. The table shows that out of 1,000 vessels 584.4 survive 10 years, 219.5 20 years, 57.2 30 years, 11.1 40 years, and none 50 years. The average duration of ships is 13.8 years; of those which have been built 10 years, 9.3 years longer; built 20 years, 7.2; 30 years, 6.2; 40

Professor Pierce expressed his interest in the paper, and a desire that a similar table might be made for English vessels, to see if the superior education of British sea-captains would be evinced.

Professor Elliott also gave the values of the standard Monetary Units in which United States securities are quoted in the com

years, 2.7.

mercial centres of Europe. In London, the 54 pence sterling, at which a dollar is rated, are really equivalent to 1.095 dollar; the Frankfort standard, two and one-half silver gulden, to 1.0144 dollar; at Paris, 1.09645 dollar; Antwerp, 1.0226 dollar; Bremen, 1.0989 dollar; Amsterdam, 1.0065 dollar; Berlin, 1.0059 dollar; Hamburg, 1.0771 dollar.

SEA-GOING SHIPS. Mr. C. W. Merrifield, F.R.S., at the meeting of the British Association, read extracts from the report of the committee on the state of knowledge of stability and sea-going qualities of ships. The report treated at considerable length on the rolling of ships in still water, followed by an account of the mechanism of waves and an abridgment of what is known on the subject of the rolling of ships in wave water. The report itself being, in reality, a very condensed abstract of our existing knowledge, it would be difficult to make a useful selection for reading. Meanwhile, it may be stated in general terms that the rolling of a ship in still water, and her behavior in a seaway, although interdependent, involve very divergent conditions. It seems that the chief point to attend to, to secure easy rolling, is that the natural period of the ship’s oscillation should not coincide, or nearly coincide, with the period of the waves; and there seems reason to suppose that we already know how, in a rough way, to influence the natural periodic time of the ship, so as to be able to predict nearly in what waves she will and in what waves she will not roll through excessive angles and with excessive quickness. But our knowledge is exceedingly crude and deficient in detail, and even our known means of observation of the height and form of waves are very unsatisfactory.

SHIPS' LIGHTS. M. Tronsens has made a communication to the Paris Academy of Sciences, in which he suggests a new arrangement of ships' lights to prevent collision at sea. He proposes the use of 3 lights, arranged in the form of a right-angled triangle, one side of which is vertical, and another parallel, with the medial line of the vessel, and towards the head, and placed in the highest possible position. The light of the summit is to be of a different color from the other two, and the distance between the lights to be about 18 feet. Observation of the two lights in a vertical line will, says the author, furnish the approximate distance from the approaching ship, and by comparing the apparent distance of the two lights on the horizontal side with that of the two on the vertical side, an idea of the ships' route may be obtained; at any rate the relative distances will show whether that course is to the right or left of the line of observation, which is the main fact to be ascertained, and that without any instrument. — Mech. Mag., July 2, 1869.

BRONZES.

The production of a fine patina on our bronze statues, instead of a coating of dust and soot, is, especially in our large cities, a thing to be desired. In Poggendorff's Annalen for April, we find the report of a series of experiments which were made by the direction of the Berlin Verein zur Reforderung des Gerwerbfleisses, to examine into the causes determining the formation of this vert antique patina on bronze statues.

The experiments while in progress led the observers to suppose that grease had much to do with the formation of the finest patina. Four busts were therefore placed in a part of the town which was very unfavorable. One of them was rinsed every day, with the exception of rainy days, and was painted once a month with bone oil, which was rubbed off with woollen cloths at once. Another bust was washed daily, but not oiled. A third was cleaned daily, but oiled only twice a year. The fourth was not touched at all. These experiments have been continued for 4 or 5 years, the result is that the bust which has been oiled once a month possesses a dark-green patina, which is considered very beautiful by connoisseurs; the bust which has been rubbed twice a year does not look so well; the others have no patina. The bust which has been washed regularly is the usual dark bronze color; the other is: quite dull and black. The final result of those who have been engaged in the experiments is: this use of oil justifies the hope that for the future we may retain beautifully patinated monuments, even in large towns. Where coal is the only combustible they will not be bright, but dark-green, and perhaps black; but they will have the other beautiful condition of the patina, the peculiar transparent property of the surface. - Quarterly Journal of Science, July.

ELECTRIC ORGAN.

A new electric organ action has been patented by Mr. Hillborne L. Roosevelt, of New York. The object of this new electric action, as well as the means employed, are very simple. In the first place it is necessary to mention, for the benefit of those who are not familiar with the usual mode of building a large churchorgan, that, as a general rule, it is a great advantage for the organist to be placed at a considerable distance from the sounding body of the instrument. To accomplish this purpose, the keyboard, at which the performer sits, is often placed on the floor of the church, while the organ itself is aloft in the gallery; and this arrangement enables the organist to form a better judgment of the effect of his performance, and also accommodate the choir. But, of course, it is indispensable to connect the key-board with the main body of the organ, in order that the keys under the touch of the player may promptly open the valves or pallets under the distant organ-pipes; and this formerly required a complicated system of wooden rods, wires, and squares, running under the floor from the key-board up to the gallery. The machinery,

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