SCIENTIFIC NOTES.

Otago Witness, Issue 1191, 26 September 1874, Page 20

SCIENTIFIC NOTES.

The British Museum was started by Sir Hans Sloane, in 1753. At Burton-on-Trent, contrary to the usual practice, the brewers use hard instead of soft water. Britannia was first put on coins by the Romans. Charles 11. revived the practice, and took Barbara Villiers as his copy for the effigy. The cats-eye is a stone of yellow-green tint, a species of the sapphire. It has threads of white asbestos within it, and the light is reflected from these in an intense manner. When this stone is properly cut, a white band of light is seen floating in its interior, that changes position as the gem is moved before the eye, which peculiarity probably suggested | the name by which it iB generally known. How much a Fly Eats. — A curious calculation has been made by an eccentric individual, well known in Paris for his peculiar antipathy to the fly. He collected 3000 flies in a room measuring 70 cubic feet. On the floor he spread a pounded loaf of sugar. At the end of four days he went to investigate the result of his experi- | ment. There remained but a spoonful of sugar. This statistician thereupon calculates that, sugar being at the rate of 4d. a pound, a fly costs the country Bd. from its birth to its demise. A Mechanical Puzzle. — There is now exhibiting in Cheapside a mechanical mystery, consisting of a large transparent ! circle, on which are sinply engraved figures and a pair of silvered hands ; and suspended without connection with any stand or visible means of setting the hands in motion, this clock gives the time accurately. Admirers of mechanical ingenuity will feel interested in this curiosity. More air can be passed through the Hoxise of Commons without draughts than through any similar building in Europe. The whole atmosphere of the House can be renewed in little more than ten minutes, and more air passes through the House when the windows are shut, than when they are open, although such is the force of habit, that members insist in hot weather on having the windows opened, and profess themselves sensibly cooler, notwithstanding that the thermometers throughout the House immediately rise one or two degrees. Such is the force of imagination, even over the minds of states- ■ men, and such the power of mind over matter. Bullock's Blood as a Medicine. — In the practice of medicine, as in other worldly matters, certain things are in fashion for a certain time. Bleeding and mercury have had their day ; cod-liver oil and chloral hydrate are already on the wane ; alcohol and bullock's blood are now in vogue among the Parisians— the former for fever and all inflammatory affections, and the latter for ancemia and pulmonary phthisis. It is said to be a curious sight in Paris to see the number of patients of both sexes and of all ranks

I and age who flock to the slaughter-house every morning to drink of the still fuming blood of the oxen slaughtered for the table. According to M. Boussingault, of all nutritive substances the blood of animals contains the greatest quantity of iron, and it is this which gives value to the new medicine. Ascent of Sap in the Bark op Trees. — M. Faivre has recently performed, says Scientific America, a series of experiments on the mulberry, hazel nut, and cherry laurel, which he considers goes far to prove the fact that the substances which supply the food of plants have an ascending motion in the bark. For this purpose, he made perfect or imperfect annular incisions, through the bark, or detached pieces of the bark, to which buds were attached, or removed entire cylinders of bark from the trunk. The result of the experiments was that the buds always continued to develop when the communication remained uninterrupted with the lower portion of the trunk ; while when this communication was completely destroyed, the buds invariably withered away. If the bud was separated by a perfect annular incision, it withered the more slowly the greater its distance from the incision ; and in these cases the starch disappeared entirely from the portions of the wood above the incision between it and j the bud. When entire cylinders of bark j with buds on them were removed, the buds continued to develop, and even pro- j duced branches bearing leaves. An Oyster Patent. — One of the great troubles, says the Scientific American, which oystermen have to contend with is the starfish. This rapacious enemy destroys thousands of bushels of oysters every year, and no device has heretofore proved effective as a protection. But the ingenuity of a Connecticut Yankee has at last triumphed. Mr. Oliver Cook, of Darien, Connecticut, has lately obtained a patent on the subject. His invention consists of spreading a net, under water, on the ground composing the oyster bed. Mr. Starfish puckers his fingers together, squeezes himself up through the meshes of the net, and then extends his digits again. Being now upon the upper side of the net, he will be infallibly captured whenever the oysterman raises the net to the surface. This is to be frequently done until the enemy ia cleared from the coast, when the oysters at once begin to laugh and grow fat. j Speech Made Self-Recording. — If a speech or discourse could be made to record itself, there would be economy of time and labour. Mr. W. H. Barlow, F.R.S., has invented a little apparatus which shows that this is possible. A mouth-piece is fitted in one side of a small chamber ; on the other side is a small delicate drum of goldbeater's skin ; a light steel spring rests on the drum, and is connected with a glass pen. On speaking or whispering into the mouth-piece, the drum is set in vibration, the spring moves in obedience thereto, and the pen records the ups and downs on a strip of paper moved by clockwork. These ups and downs vary with the spoken words, being most marked where consonants prevail ; and thus whatever is uttered by the speaker is accurately recorded on a continuous strip of paper, and can be read off by any one acquainted with the signs. This is not the first time that an attempt has been made to record the sounds of the voice by mechanical contrivance, and it will not, as yet, supersede the shorthand writer ; but uses may be found for Mr. Barlow's instrument which its inventor never contemplated. The Purity of Gold. — The purity of gold is still denoted by the use of the term carat. This word, which like the Troy grain, and the Latin siliqua, is thought originally to have denoted a seed or pod, taken for the unit of weight, appears to have been the basis of the ancient Chaldean system of weights. As a positive dimension, it is not only commonly used by the diamond merchant (four diamond grains go to one diamond carat, which is the equivalent of 32 grains Troy), but the term is still employed to denote the purity of gold. Absolutely pure gold is said to be 24 carats fine. It is a curious fact that this weight of 24 carats, if taken as a positive quantity, of 76 - 8 grains Troy, is exactly the fifth part of the Sela, or silver unit, which was introduced into Palestine after the conquest of Babylon by the Persians. This coin was one fifth part heavier than the shekel, the silver unit which prevailed • from the earliest known times down to those of the Persian empire. And the Daric, or gold coin of the Persians, specimens of which exist in our museums, has a distinct relation of weight and of value to the Sela of 384 Troy grains of silver. Dr. Dullo gives an account in the Journal d'lndustrie, of the method adopted in Germany for covering cast iron objects with copper. He says the surfaces are cleaned with a brush and hydrochloric acid, and the objects are then left in water slightly acidified ; they are afterwards placed in a bath composed of 25 grammes of oxide of copper, 107 grammes of hydrochloric acid, a quarter of a litre of water, and half a litre of alcohol. A regular deposit of copper takes place on the surface of the iron, the rapidity depending upon the proportion of the alcohol, which is the active agent to the other ingredients. The iron may be coated with the aid of pure alcohol only, but in this case the deposit is very thin, and in the form of chloride of copper, which is converted in the end into metallic copper. The chloride which adheres to the surface should be carefully brushed off after the operation, and the surface dried. If iron thus coated with copper is placed in a bath consisting of 10 grammes of chloride of iron and if litre of alcohol, in contact with metallic

zinc, the surface is, covered with a fine silvery deposit, which adheres firmly to the copper. Copper may also be covered with a layer of antimony by the following process. Dissolve chloride of antimony in alcohol, and add hydrochloric acid until the mixture becomes clear ; clean the copper well, and leave it in the bath for three quarters of an hour. The effect of the alcohol in the preceding process is thus explained : it moderates the precipitation of one metal from its solution by another metal and causes the precipitate to fall in an extremely divided state ; when alcohol is used alone, without water, the coating of copper thrown down is reduced to the last degree of tenuity. It is recommended that when the work is finished it should be well washed, first in water, and afterwards several times successively with a solution of carbonate of soda, and with weak hydrochloric acid, and finally carefully dried in a warm place. Origin of Ambergris.— The true origin of ambergris, which is highly valued in perfumery, was a matter of great dispute in former times. It is found floating in the sea or cast upon the sea-shore in the neighbourhood of Madagascar, Jamaica, Bermudas, Maldives, Brazil, Molucca, Japan, China, the coast of Africa, and it is said to have been also found on the west coast of Ireland, the coast of Norfolk, and near the Orkneys. The greatest supply now coming into the market is from the Bahamas and Morocco. Formerly several theories as to its nature existed. The inhabitants of Madagascar said it was a kind of bird guano ; secondly, it was said to be a kind of bitumen from springs ; thirdly, aseamushroom ; fourthly, a vegetable wax or gum. The real fact, however, is that it is simply a secretion from the intestines of the sperm whale. It is generally met with floating in the sea, but it is also met in the intestines of sperm whales — healthy whales do not carry it, but it is found in dead or sickly whales. It is always in one place inside the whale — namely, at from two to seven feet from the termination of the intestinal canal. One writer, therefore, thinks that it is a secretion which collects in the csecum of the whale, and, from the fact that it is found only in dead or dying whales, he conjectures that it may be the cause of the death of the whale. There can, however, be no doubt whatever that ambergris is the refuse of the whale's food collected in a morbid form. On looking at it very closely, we find that it is deposited in regular layers. By delicate manipulation, we find that ambergris will split oft* in layers as one splits up the pasteboard cover of an old book.