SCIENCE NOTES.

Otago Witness, Issue 2295, 24 February 1898, Page 48

SCIENCE NOTES.

• . • The longest distance encompassed by : the humEn vision, so far as the records go, is j 183 miles, between the Uncompahgre Peak, in Colorado, and Mount Ellen, Utah. This I feat was accomplished by the surveyors of the United States Coast and Geodatic Survey, i who ara now engaged in conjunction with representatives of other nations in making a i-ew measurement of the earth. The observers on the Pacific Coast have been able to signal from Mount Shasta to Mount Helena, a distance of 100 miles, bub have never been able to get a response. Between the other two peaks communication has been continuous for an hour or more on several occasions. The Uccompabgre Peak is 14,300 ft high, while Mount Ellen iB 13,40Ufr. The longest distance that the human eye ever reaohsd until this record was made was between Algiers and Spain, a distance of 168 crilae. The measuring of the earth, which is now going on, is no simple task. Toe width of the ocean can only be ascertained by astronomical observations. The observers at Greenwich and Washington note each night the exact moment of the rjsiDg of certain etarß, and then by mathematical calculations turn this d.Serence in time into distance. The result is corrected and corroborated by further observations upon other stars and by a series of experiments which furnish an average which is approximately accurate. Tiie difference is seldom more than a small fraction of a second, and is attributed to atmospheric phenomena. The Pacific Oceaa is measured in a similar manner by joint observations with the Lick teletc«po, in California, and that of the Imperial University at Tokio, Japan. — Railway and Engineering Review. • . • The announcement that the limits of the universe have been reached by human vision is startling. Professor Newcomb, reccgGised as one of the greatest of living astronomers, says evidence is accumulating which points to a probability that the small stars which our powerful modern telescopes have brought into view do not look small because they are further away, but by reason of their inferior size. There are no more beyond. In other words, we are actually able to ccc ths boußdaiies of our universe. Of this universe we know the gsneral form. It has the shape of an enorraoua disc, the solar system being not far from the centre. We may &ay that this disc, so inoonceivably huge, has a diameter four or five times its thickness. As to the length of the diameter we cannot speak with great accuracy, because we are not acquainted with the precise distance of many o£ the stars. ITsfty years hence we shall know a great deal more on that subject than we do at present. We may say that the distance across the disc, trom one side of the universe to the other, is 20,000, or may be 30,000, light years. There is a wide margin of guess in the estimate. A light year is the distance which a ray of light will travel in one year. One c^n figure that out himself, the rate being 186,000 miles a second. Ifc takes a little over eight minutes for light to come to us from the sun, which is 93,000,000 miles away. The light by which we are able to see a very distant star through a telescope may have started from that star 25,000 years ago. Assuming that to be the case, ifc is 25,000 light years away from us. We can see about 5000 stars with the naked eye. With the most powerful telescope we can see perhaps 50,000,000. There is no telling how many millions more there are unobserved. One may got a notion of measurements from the fact that the radios of the earth's orbit, a line 90,000,000 miles in length, not only vanishes from sight before we reach the distance of the great mass of stars, but from that distance becomes such a mere point that the most delicate appliances fail to make ifc measurable. — San Francisco Minicg and Scientific Press. • . • The terms " energy " and " power " are often carelessly used the one for the other. Energy is the ability to perform a certain amount of mechanical woik, and power is the ability to perform it at a certain rate. A trolley wire conveys energy, not power, from the power house to the motor of an electric car. When it reaches the motor it is converted into power, which is expended in the performance of work. The boiler of a locomotive transmits that form of energy known as heat from the furnace to the water in the boiler. The boiler doss no work. It is a figure of speech to say ■ that it works well or ill, or that it transmits power. The steam pips leading from the boiler to the steam chest of an engice cylinder transmits | the heat energy generated in the boiler. When the steam reaches the cylindor, and the piston moves, energy is converted into | work, which, when quantitatively expressed in units of works performed in a specified time, lis power ; but rope- or belt transmissions are I examples of power transmission. • . • Recently the Duke of Argyll delivered a lecture at Inverary on the subject " Wbat is Science 1 " Ha said the question commonly put to the public and dealt with in public speeches was not "what is science 1" but " what has science done 1 " Assuming chat all knew what science was and what j science had done for us, especially during j the laßt century, there followed almost j always the long r-ongs of triumph with which j we recorded the progress of invention, and j showed the immense advantages which it had conferred on human life. He was not going to enter on that at all. He thought it was possible to gat a little tired of these songs of triumph, progress, and invention ; they werß infinite, or at least indefinite, and no doubt j great discoveries remained before us. He | wished to put the question, " What was science itself 1 Wbat were its ends 1 " He wished fco consider science in relation to higher thoughts and interests of men. That | was a fresh subject, and it was one of enormous extant. Science meant systematic knowledge, and there were many questions in science which we could not answer. At the conclusion of his lecture the Duke alluded to the discovery of light as one of the most wonderful things of modern times. • . • Under the heading of " The Annus Medicus, 1897," a general review of the progress of medical science for the year, the Lancet says that an account of the surgery for the past year would be incomplete vfitli-

oat some account of the present usa of the Rontgen rays. Though it Ib still doubtful what their exact nature may be, yet we can obtain them with more ease and certainty than before. An adjustable vacuum tube has proved very useful. Dr J. Mackenzie Davidson has devised a very ingenious ap- | paratup, by which the exact position ;of an object photographed by the aid of the Rontgen rays can be determined within a faw minutes after the Degative is taken. It has been fully tested on the living subject, and has proved very accurate. It has become almost a routine practice to use the X rays in cases of fracture or dislocation in which any doubt exists as to the exact lesion present, and skiagraphy has also been used to some extent. Dr W. S. Hedley has shown that if paper or other flexible sensitised surface is used to obtain the skiagram it must be kept quite flat and not benfc round the limb, or distortions will be shown which do not exist. The Rontgen Ray Society, which wss formed a few months ago, should, says the Lancet, advance our knowledge of the scientific and practical aspects of the rays. • . • Ifc looks as if we were gradually but surely passing to a lower general temperature in these latitudes. Observation does not, it is true, show that the mean temperature is lower than it was a century ago ; but the disappearance of many plantß which formerly flourished on this island and ia Central Europe seems to indicate that such a change i» in progress. A writer in "La Semaine Horticole " draws attention to certain changes which have occurred aail are occurring in France at the present time, which favour the idea that the climate is becoming cooler. Many trees that, formerly flourished in the north of France are no longer found there, and can only be met; with in the extreme south, while several have entirely disappeared from the country. The lemon, once so general and prevalent in Languedoc, no longer grows there, and an orange tree oannot be found in Roussillon, where orange 'groves existed long ago. The Italian poplar, bo common asd so picturesque in anoient French etchiegs, is now rarely found on French soil, and only in the southern part of the Republic. France was of old the frnifc garden of Europe, but the changes of temperature have greatly limited the number and variety of fruits which can be grown in that country, and considerably restiicted the area in which they nourished. ' . • Nirrogradeky if, on account of his extendad and thorough studies of microoiganisms, well known in connection with the subject of nitrification. He has now given the result of bis studies on the above topic. In isolating these organisms, he used what is by him termed the "elective" method of isolation. In this special case a culture medium was employed that was free from all combined nitrogen. It was mads up as follows : — Distilled water, lOOOcc ; 20 - 40gr dextrose, Igr potassium phosphate, 0 sgr magnesium sulphate, 0 01-0 02gr potassium chlorate, sulphate of iron, sulphate of manganese. This culture medium was then inoculated with garden earth. Most of the cultures soon showed evidence of butyric ecid fermentation, gas-bubbles appearing in the immediate vicinity, small masses floating in the medium. These masses somewhat resembled kephir grains. This fermentation continued till all of the 6ugar was used up. After this fermentation mould developed on these white grain-like masses, followed by algas. It appears that this medium, at first wholly unsuited for higher plants because of the absence of nitrogen, was made suitablg when appropriation of nitrogen by bacteria had taken place. The kephir-like masses consisted of a species of Cloetridium, to which he bas given the name of O. pasteurianum, and two kinds of bacteriaforming threads. The interesting details cannot be given here. Suffice it to say that this Olostridium is capable of obtaining nitrogen from the atmosphere, which is found in the medium in part as soluble inorganic nitrogen, but mostly as insoluble organic combined nitrogen. — " Archives dcs Sciences Biologiques," St. Petersburg.