23. To restore Decayed Ivory.—Mr Layard, in his explorations among the ruins of Nineveh, discovered some splendid works of art carved in ivory, which he forwarded to England. When they arrived there, it was discovered that the ivory was crumbling to pieces very rapidly. Professor Owen was consulted to know if there was any means of preventing the entire loss of these specimens of ancient art, and he came to the conclusion that the decay was owing to the loss of the albumen in the ivory, and therefore recommended that the articles be boiled in a solution of albumen. The experiment was tried, with complete success, and the ivory has been rendered as firm and solid as when it was first entombed.

24. Ivory as an Article of Manufacture.—There are several sorts of ivory, differing from each other in composition, durability, external appearance, and value. The principal sources from which ivory is derived are the western coast of Africa and Hindostan: Camaroo ivory is considered the best, on account of its colour and transparency. In some of the best tusks the transparency can be discovered even on the outside. The manufacturers have a process by which they make poor ivory transparent, but it lasts only for a short time. A third kind of ivory, called the Egyptian, has lately been introduced, which is considerably lower in price than the Indian, but in working there is much waste. By an analysis, the African ivory shows a proportion of animal to earthy matter of 101 to 100; the Indian, 76 to 100; and the Egyptians, 70 to 100. The value of ivory consumed in Sheffield, where it is much used in making handles for cutlery, is very great, and nearly 500 persons are employed in working it up. To make up the weight of 180 tons consumed in that place, there must be about 45,000 tusks, whose average weight is nine pounds each, though some weigh from 60 to 100 pounds. According to this, the number of elephants killed every year is 22,500; but allowing that some tusks are cast, and some animals die, it may be fairly estimated that 18,000 are killed every year merely for their ivory, which is contrary to the usual belief that the ivory used comes from the tusks cast by living elephants. These estimates, it will be seen, are for Sheffield merely.

25. Flexible Ivory.—M. Charriere, a manufacturer of surgical instruments in Paris, has for some time been in the habit of rendering flexible the ivory which he uses in making tubes, probes, and other instruments. He avails himself of a fact which has long been known, that when bones are subjected to the action of hydrochloric acid, the phosphate of lime, which forms one of their component parts, is extracted, and thus bones retain their original form and acquire great flexibility. M. Charriere, after giving to the pieces of ivory the required form and polish, steeps them in acid alone, or in acid partially diluted with water, and they thus become supple, flexible, elastic, and of a slightly yellowish colour. In the course of drying, the ivory becomes hard and inflexible again, but its flexibility can be at once restored by wetting it either by surrounding it with a piece of wet linen, or by placing sponge in the cavities of the pieces. Some pieces of ivory have been kept in a flexible state in the acidulated water for a week, and they were neither changed, nor injured, nor too much softened, nor had they acquired any taste or disagreeable smell.

26. Air-Whistle.—Mr C. Daboll, of New London, Connecticut, has invented a whistle that speaks with a most “miraculous organ” whenever its services are required for the purpose of alarm or warning. It is designed for the use of vessels at sea or on the coast, as on our eastern shores, where dense fogs prevail, and vessels are liable to come in collision before they are conscious of each other's approach. Its great advantage is its power of communicating sounds for a distance of from 4 to 5 miles, far exceeding the largest bells. An experimental one has been placed on Bartlett's Reef, and the pilot of the “Lawrence” states that he has heard it when about 4 miles off from Bartlett's Reef, against the wind, which was blowing quite fresh at the time. This was on a clear day, and when the whistle was blown at his request, and also by advice of the inventor, so that the distance might be marked. It is probable that, under the same circumstances, the tones of a bell could not have been heard more than from one half to three-fourths of a mile. The pilot of the steamer “Knickerbocker” reports, that he made the whistle during a dense fog, thirteen minutes' running-time of the steamer, before coming up with the station where it is located. He therefore must have been some four or five miles distant from it when he heard it.

This whistle consists of an air chamber or condenser, of boiler iron sufficiently[N33] strong to resist almost any pressure, an air-pump, and a whistle similar to the ordinary ones used on locomotives. By means of the air-pump operating into this chamber, a pressure of air is obtained in it of any required amount,—say one, two, or three hundred pounds to the square inch. When the air is so compressed, it is made to operate the whistle by simply opening a valve, and gives a distinct clear sound.

A memorial has been presented to the Treasury Department, signed by most of the commanders and pilots of the steamboats running through Long Island and Fisher's Island Sounds, setting forth the advantages to be derived to navigation from this whistle, and urging that it be introduced into the light vessels, and at all stations where the government intends to afford protection to navigation.—Annual of Scientific Discovery, p. 70.

27. Curious Electrical Phenomenon.—We learn from a letter from a gentleman connected with the Bay State Mills, at Lawrence, Massachusetts, some facts with reference to a new and curious application of electricity which has been introduced in those mills. The electricity is generated by the motion of the machinery, and is employed for lighting up the gas burners. It exists in large quantities in the card-rooms, where there are many belts running on iron pulleys, and, in the cold dry atmosphere of winter, often producing serious damage to the quality of the cording. The manner in which it was discovered that this electricity could be applied to “lighting up,” is somewhat curious. When the gas was first let into the pipes in the mills, one of the overseers discovered fire setting out from one of the pipes near a belt, and on examination it was ascertained that a small stream of gas was escaping. It was surmised that it had been ignited by the electricity, and to prove it, an experiment was tried. Near a large belt in the carding-room was a gas-burner, and on a bench between them there was placed a small quantity of wool, which is a non-conductor of electricity. If a person stood upon this wool, reaching one hand within two or three inches of the belt, and touching the gas-burner with one finger of the other, the escaping gas was at once ignited with an explosion like that of a percussion-cap,—the body of the operator thus being made the medium for conducting the electricity.

The writer adds,—“We shall be able to make a great saving of expense in the woollen manufacture, as soon as we can discover an effective method of conducting the electricity away from the cards, as we shall then be able to dispense entirely with the use of oil on the wool, we shall save at least $30,000 per annum, when the mills are in full operation.”—American Annual of Scientific Discovery p. 117.

List of Patents granted for Scotland
from 22d March to 22d June 1850.

1. To James Higgins, of Salford, in the county of Lancaster, machine maker, and Thomas Showfield Whitworth, of Salford aforesaid, “improvements in machinery for preparing, spinning, and doubling cotton, wool, flax, silk, and similar fibrous materials.”—22d March 1850.