SCIENCE NOTES.

Otago Witness, 5 December 1900, Page 62

SCIENCE NOTES.

— Arrangements have been made in Hamburg for the employment of electric power in the loading and discharging of cargoes by means of a simple and newly-invented apparatus which is small in dimensions and can be hung directly upon the loading or unloading boom. The application of this new method will, it is claimed, considerably reduce the time now taken for the discharge or shipment of cargoes (which for large vessels may amount to 12 or even 15 days), and in the case of grain cargoes it is reckoned that the time will be reduced by at least one-half, and the operation will be almost automatic. It is estimated, indeed, that in case of necessity as much as 400 tons of grain per hour may be shifted, and that a vessel loading 5000 tons of grain will get despatch in less than 48 hours. It has already been tested, and has yielded, according to information from Hamburg, the most satisfactory results. If this new departure justifies the hopes reposed in it, the saying in the working of large steamers will be immense.

— In the course of his presidential address to the British Association at Bradford, Sir William Turner dealt with the subject of bacteria, and said the observations of Cohn, made about 30 year 3 ago, and those of De Bary shortly afterwards, brought into notice a grovip of organisms to which the name "bacterium" or "microbe" is given. They were seen to vary in shape ; some were rounded specks called cocci, othei'3 were straight rods called bacilli, others were curved or spiral rods, vibrios or spirilla*. All were characterised by their extreme minuteness, and required for their examination the highest powers of the best microscopes. Many bacteria measure in their least diameter not more than one-twenty-iive thousandth of an inch, one-tenth the diameter of a human white blood corpuscle. Through the researches of Pasteur, Lord Lister, Koch, and other observers, bacteria have been shown to play an irrportant part in Nature. They exercise a very remarkable power over organic substances, especially those which are complex in chemical constitution, And can resolve them into simpler combinations. Owing to this property, some bacteria are of great economic value, and without their agency many of our industries could not be pursued ; others, again, and these are the most talked of, exercise a' malign influence in the production of the most deadly diseases which afflict man and the domestic animals. Great attention has been given to the structure of bacteria and to their mode of propagation. When examined in .the living state and magnified about 2000 times, a bacterium appears as a homogeneous particle, with a sharp definite outline, though a membranous envelope or wall, distinct from the body of the bacterium, cannot^ at first be recognised ; but when treated with reagents a membranous envelope appears, the presence of which, without doubt, gives precision of form to the bacterium. The substance within the membrane contains granules which can be dyed with colouring agents. Owing to their extreme minuteness it is difficult to pronounce an opinion on the nature of the chromatine granules and the substance in which they lie. Some observers regard then as nuclear material, invested by only a thin, layer of protoplasm, on which view a bacterium would be a nucleated cell. Others consider the bacterium as formed of protoplasm containing granules capable of being coloured, which are a part of the protoplasm itself, and not a nuclear substance. On the latter view, bacteria would consist of cell plasm enclo&ed in a membrane and destitute of a nucleus. Whatever be the nature of the granule-containing material, each bacterium is regarded as a cell, the minutest and simplest living particle capable of an independent existence that has yet been covered.

— Xt is a matter of common knowledge that the cuckoo deposits its egg in the nest of some bird which it selects to play the role of foster-mother; but hitherto it has been a moot question how the cuckoo conveys the egg to the nest. It has been generally supposed that the bird carries it in its beak, and several observers have stated that they have seen the egg so carried. In the June number of the Zoologist, Mr A. H. Meiklejohn states how he was fortunate enough to be a witness ot the entire transaction, and he is of opinion that the throat of the bird carries the egg. He states that the cuckoo which formed the subject of his observation, was constantly opening her mouth during a preliminary encounter with the robins whose nest she assailed. He is certain that the egg could not have been laid in the ordinary way in the ne3t, and that the throat of the cuckoo presented a slightly distended appearance, which might well have been due to the presence of the egg. — Mr Acting-consul Kestell Cornish, in his report from Zanzibar, tells of an interesting discovery which has recently been made, that the fruit of a tree which grows principally at Dunga will, on being tapped with a knife, produce a white fluid, which, when placed in boiling water, coagulates into a substance closely resembling gutta percha ; this in the process of cooling becomes hard, but can in its previous soft state be moulded into any required shape. It was intended that samples of this produce should be taken to London, and doubtless by this time expert opinion has decided whether it is actually gutta percha or not. It is not improbable that it will prove to be an inferior order of that article. Should it be found to be worth anything, however, a large source of revenue may be derived from it, particularly if, as is quite likely to be the case, it is discovered in the sister island and upon the mainland.

— Air Ernest A. Faller, a German residing in San Francisco, lias secured a patent on multiplex telephony, the idea of which consists broadly in causing the instruments which are to be used in transmitting the conversation to sympathise or agree as to their electrical conditions when the same are brought from their condition of rest or inactivity into use, and at the same time causing certain adjustments to take place in all the instruments which are not wanted, so that upon the next pair of instruments being brought into use their electrical conditions, while mutually haimonising, will differ from those of the pair already in upe, and this same action takes place in respect to the idle instruments whenever another new pair of instruments is brought into use.' Hence any idle instrument at one end ot the line can establish communication with any idle instrument at the other end of the line while a conversation is being carried on' between the active instruments. This he accomplished by providing tlia several branches leading from the terminals of the line with condensers whose individual capacities may be varied or adjusted, induction coils, the electric condition _ of whose secondaries may be changed by bringing in more or less turns, and receivers provided with double windings capable of being worked in series or in multiple. By means of a special switch he connects the independent windings of the said receivei in multiple or in series, the said switch simultaneously Kfidlicing 91 M-Qi'easiasi the cajja-

city of the condenser and the number of turns of the secondary coil in the inductorium in the ratio of, say, one to two or one to three, and thus changing the condition of the instrument both as to capacity and resistance, so that said instrument may be used in the transmission of articulate speech with another instrument in which like conditions exist as to capacity and resistance ; but with no other. The active surface of the condenser, the number of turns in the secondary coil of the indnctorium, and the windings of the receiver are proportioned in such a way as to cause the receiver to respond only to a current of a certain tension and amperage. For instance, if the switch is in such a position as to connect the windings of the receiver in series and the entire surface of condenser and winding of the secondary in curcuit, a current, coming from a station in whose instruments like connections and conditions exist, will cause the receiver to respond, while a current emanating from a station in whose instruments different connections and conditions exist, will -leave the said receiver silent, or practically so. — Electrical World. — The occurrence of a solar eclipse has once more called attention to that strange appearance which is known as "the, shadowbands." These are ripple-like b(_J lr » which are seen to chase one another across sAc surface of the earth a few minutes Tjefore and just after totality. The appearance has' always aroused much interest ; but no definite explanation of the phenomenon has" as yet been formulated. One of the best theories which we have noted is that of a correspondent of the Scientific American, who paid special attention to this question when observing the recent eclipse, and was able to' watch the shadow-bands as they traversed a broad level path of white sand. He says that the bands — or "shadow-lines," as he prefers to call them — are similar to the shadows which would appear on the bottom of a shallow pool of water when the wind ruffled its surface. They were six or eight inches apart; and he attributes their appearance to the passage of the moon's shadow causing an undulating^ motion in the atmosphere close to the earth's surface— that is, "to the undulations of a stratum of heated air passing directly over our heads." He further notes that the cold at the time was distinctly perceptible, and that his party had to resort to wraps. — It has not hitherto been suspected that oui great metallurgical establishments were manufacturing precious stones without intention. Its possibility, however, might have ueen anticipated when M. Moissan made his experiments, ending with the artificial production of the diamond. He obtained this gem by suddenly cooling under high pressure the cast metal saturated with carbon. The same conditions are realised to a greater or less extent in the blast furnaces for manufacturing special steels, by sudden cooling of the fused metal under high pressure. In this class of steels there must be diamonds, microscopic wiihout doubt, and Professor A. Eoseel, of the University of Berne, has been conducting experiments in the laboratory of inorganic chemistry for the purpose of ascertaining whether such diamonds really exist. A considerable number of steels of various production have been examined and treated in the same manner. From a piece of compact steel a portion of about three hundred grammes was cut of? and treated with nitric acid. The insoluble residue .consisted principally of carbon, especially in the state of graphite, combinations of silicum, etc. It was washed with water and then boiled three times with fuming nitric acid, which partially dissolved it. They even obtained a dilution of the density of 1.8 by washing and successive additions of fluor-hydric acid ; then' of fuming sulphuric acid. There remained only graphite- which was washed, dried, and dissolved with potassium chlorate. This long series of operations was commenced again, for it was deemed necessary to pass the residue through the whole series of treatment that has been explained. At last the chemist |iad the satisfaction, after a treatment of boiling sulphuric acid, of finding a deposit that could be attacked. The residue finally obtained with so much trouble fell to the bottom of the vessel filled with a heavy liquid as methyliodide. With the aid of a strong microscope, minute transparent octahedrons were descovered, which burned on a leaf of platina and in a current of oxygen, disengaging cai'bon, and "almost without leaving ash. M. Rossel had really discovered diamonds in steel. — La Diamante.