SCIENCE NOTES.

Otago Witness, Issue 2088, 1 March 1894, Page 48

SCIENCE NOTES.

— Electrical propulsion of commeroial boats on canals is no longer a theory, but a demonstrated success. The new power was successfully tested at the village of Brighton, four miles from Rochester, on the water way of the Erie Canal, on November 17. The old steamboat Ceres, now the Frank W. Hawley, was fitted with an electric motor by the Westinghouse Company instead of a boiler and engine, taking power from a trolley wire overhead. She started off without a hitch or hindrance. The electric current was taken from the Rochester street railway, and usei 500 volts power. The prinoiple is the same as that of the streetcar system, except that the return current is carried overhead the same as the supply current. The lateral movement of the boat, which allows it to pass another, is provided for by using a pliable wire for a trolley. The boat made from four to seven miles an hour. It is said it was capable of towing six other boats at a good rate of speed. If power can be obtained from Niagara, as it is suggested it can be, 50c per day will get the power for a canal boat that it takes four mules and two men to give it now. That means that 2|c will carry a bushel of grain from Buffalo to New York, and that 2£c is going to deliver it in Buffalo from Duluth. Five cents brings a bushel of wheat from the wheat fields to the metropolis.

— Mr Scott Moccrieff's method of filtering sewage from its deleterious organisms by means of a succession of " cultivation filter beds " has been examined by Dr Houston, an Edinburgh bacteriologist, at Mr Moncrieff's laboratory at Ashstead, and it is the eubjeot of an exhaustive report, which confirms the absence of microbes in the sewage thus treated, while Mr Lawford vouches for it from an engineering point of view. According to these experts sludge treated by this process passed through layers of broken flints, and along a channel of coke, emerges clear, almost inodorous, and deprived of disease-breeding microorganisms.

— A mechanical system of wood carving has been patented by the Wood Carving Company (Limited), of Birmingham, by means of which the decoration of wood in numerous designs can be accomplished cheaply and well. Electric light casings with their carved surfaces can be supplied, we are told, at a cost very little in excess of the plain casings ordinarily in use.

—In the use of the mixed gases for lantern purposes, the question sometimes arises as to whether coal gas or pure hydrogen is most readily exploded in case of a rise of temperature. An important contribution to our knowledge of the matter has recently been made by Professor Victor Meyer in conjunction with his assistant, Herr A. Miincb. It was found that with purer hydrogen and oxygen the initial temperature required to cause explosion varied between 612deg and 686deg, no difference being found whether the gases be dry or moist. The presence of platinum foil prevented explosion, quick combustion always took place even when a temperature of 715deg was reached. When hydro-carbons were used with oxygen, it was found that the temperature needed to induce explosion was lower the greater the proportion of carbon present. Thus the mean temperatures of explosions with methane, ethane, and propane were 667deg, 616deg, and 547deg respectively. It will thus be seen that, whatever the difference may amount to in practice, it is a fact that pure hydrogen and oxygen will be more difficult to explode Jtban mixtures of coal gas and oxygen. — British Journal of Photography.

— A great many new steel processes have been reported lately. One of the most recent is the Dawson process, which is said to have been tried in Cincinnati. In this process the inventor takes tcrap iron or steel and treats it with a combination of chemicals while in a state of fusion in an ordinary crucible. When melted the liquid metal is cast in sacd in any desired shape, the result being, we are told, the highest grade of steel. The rolling manipulations are' entirely omitted and it is found that the product has combined caibon, bat in quantities so small that it would be utterly valueless under the old process.

—An ingenious * little instrument has (writes a B.Sc. in the Adelaide Observer) been devised to enable doctors to measure the amount of trembling of patients who are affected with tremor. A metal plate is fixed vertically with a number of holes of different sizes bored in it, and the patient is requested to hold a needle at the centre of any one hole. If his tremor is so great that the needle knocks against the side of the hole it causes an electric bell to ring at each contact, and he has then to try a larger hole till he finds the wze at which he can just avoid ringiDg the bell. The diameter of the hole is the size of his tremor. With such an instrument a marksman can ascertain whether he is in good form for shooting, and how much different things put him out of form. The surgeon who is going to perform a very delicate operation — say on the eye— can assure himself whether his hand is steady enough or not. A patient who has been drinking too much tea -or coffee can have proved to himself in a visible manner

the benefits resulting from a course of milk and water ; while the poor trembling victim of excessive nobblers and nips can be got to see before his very eyes that teetotalism is for him the way towards better things if he can only be got to practise it for a little. In a general way the instrument will indicate whether a person is steady in more senses than one, although it is to be remembered that some tremor is constitutional, and not the fault of the individual, as, for instance, in old age and in nervous subjects.

— Professor Barnard, of the Lick Observatory, recently gave an interesting lecture on comets. " Comets," said the speaker, " are bodies of gaseous matter, a little drier toward the middle than at the outsides. As this middle descends toward the Bun i grows brighter, and a little star-like body appears and emits jets of brilliant matter, which streams oat as a nebulous body and forms the tail. What before was small in dimensions extends to enormous sizes, stretching out 200,000,000 of miles. What this matter is we know not. It is supposed the tail is composed of vapour. This we are not sure of. The spectroscope does not reveal correctly or satisfactorily what they are. Hydrocarbons are found in them. When a comet passes between the earth and a star you can see the star through the comet. You think the star is in front, when it is known positively that the star is farther away than the comet. What the nucleus is composed of we know not. No astronomer has positively seen a nucleus of a comet pass between the earth and a star. So it is not certain whether this centre spot is transparent or opaque. It is supposed that the nucleus is composed of meteoric stone."

— A tendency may remain dormant, and perhaps unsuspected, not merely for one but sometimes for many generations, becoming at last manifest again in a remote descendant. And this is as true of mental and moral tendencies as of physical. In short, the observed facts would seem to warrant the conclusion that the organism never relinquishes any tendency it has once acquired, bnt holds it in stock, if need be, generation after generation, awaiting a favourable opportunity to herald it forth. Only by such a supposition can we explain the commonly observed fact of inheritance from remote ancestors, or, as Darwin termed it, atavism.

— The contagiousness of cancer is hard to demonstrate. It haß been reported to the Paris Academy of Sciences that out of a number of attempts made to communioate human cancer to animals, only one had been successful ; still one really good positive result would be a demonstration of the parasitic nature of the disease. A parasite has been demonstrated in cancer, but the question to decide is whether it is cause or accompaniment only.

— Dr Orranos, of San Luis Polosi, Mexico, read an interesting paper before the recent Pan-American Congress, Washington. His subject was " Pneumonia : its Dangers as an Infectious Disease." He referred to the three oljmates of Mexico, Tierra Fria, Ternplado, Caliente, or its cold, temperate, and coast or tropical climate. He dwelt on the distribution of pneumonia from Zacatecas, in its highlands, to Campeachyj on the Gulf of Mexico. March and April, at the close of the Mexican winter, gave the heaviest death rate. In some places it was more fatal than others. He cited much of general interest regarding infected houses, citing case after case in the same house, visitors to pneumonics having contracted the disease and taken it to others — in other words, its propagation by individuals and air. Malaria and pneumonia had a rdle frequently observed in Mexico. He deems the disease highly infectious. He cited a case of a man who died of pneumonia. A month later bis clot hi r.g vas sent to a family. Soon after two children in that house were ill with the disease. Another illustration was that of a woman who nursed a pneumonic — sleeping in the game room ; she likewise contracted the disease. An examination of records of cases of pneumonia in given localities bad proved very instructive. In two years 31 cases had been traced to infected houses, case after case in the same house. The germ of the disease, the pneamococcus, he deemed almost indestructible in Mexico.

— The first iron ship was launched about 60 years ago ; now the carrying power of the world's iron shipping exceeds 36,000,000 tons.

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