The tables were speedily cleared away, the piper soon discoursing stirring music from his pipes; with the satisfaction of seeing the Duke lead off his beaming child as partner in the first reel. Daylight peeped in before the pipes were quieted, or the noise and merriment of the company were hushed.
And now, before the door of a cottage that has been built within a short distance of the piper's, there are to be seen three fine boys and a 'sonsie' lassie, the eldest rejoicing in having a Duke for godfather; and a proud man is the piper as he teaches Archie the oldest boy how to extract martial music from a sheep's bladder, which the ingenious youth has converted with skill into home-made bagpipes. To this day, the piper, on whom years are beginning to tell their pathetic tale, meets his friend the game-keeper once or twice a week at Mrs MacDonald's clachan among the hills, and the toast which always furnishes an excuse for the one extra glass that the piper thinks needful to send him cheerily on his way home is—'Cott pless the Teuk!'
[THE MONTH:]
SCIENCE AND ARTS.
We often read in the newspapers that a certain ship has been taken out to the 'measured mile' for trial of her speed, which means that, in order to try the steam-engines, they must be put into the ship, and the ship into the water. Like much else in English practice, it is an uncertain way of finding out that which ought to be previously known; for it is a trial of more than the engines, seeing that it includes the merits and defects of the boilers and of the ship, and the behaviour of the steam, which exercise an important influence on the result. If, therefore, the engines only are to be tested, the trial might as well be made while the vessel is still in dock; and while still in dock there should be some means for ascertaining and accurately indicating their capabilities. This means has been invented by Mr Froude, F.R.S., who has already done so much for the science of shipbuilding; and his new dynamometer seems likely to fulfil the intended purpose. It combines some of the most recondite principles in mechanical philosophy, but may be roughly described as a turbine with its segmental divisions so constructed that, when set rotating, the water inclosed is urged into a state of resistance. This resistance varies with the speed and power of the engines; and a spring lever, communicating with the interior of the apparatus, indicates the variations on an external scale. The turbine will be temporarily fixed to the end of the screw-shaft, the engines will be set to work, and as the shaft spins round, the power of the engines will be clearly and independently demonstrated, even up to eight thousand horse-power, if required. The capabilities of the engines having been thus accurately ascertained while the ship is still in dock, it will be possible, when trying her over the measured mile, to define how far her speed is affected by other influences, in summing up the result. A working model of this ingenious invention has been exhibited to the Admiralty and at scientific gatherings in London.
Mr Cochot, 34 Avenue Lacuée, Paris, has constructed a small steam-engine of half a horse-power, for use in petty manufactures, which, as he states, will work ten hours at a cost of not more than fourteenpence for coal.
Mr Redier, clockmaker of Paris, has exhibited to the Société d'Encouragement pour l'Industrie Nationale a balance which registers variations of weight. In this ingenious instrument clockwork is so arranged in connection with a copper cylinder, suspended in a vessel of water, as to produce two antagonistic movements, one of which comes into play whenever excited by the action of the other. By this alternate movement the registration proceeds steadily, and is recorded by a pencil on a band of paper. An exceedingly light spring lever is so combined with the clockwork that it will keep a comparatively heavy weight in action; such as holding a barometer free to rise and fall while the column of mercury stands always at the same level. Many applications may be made of this instrument, especially in the sciences of observation. Its sensibility is such that it will register the loss of weight in a spirit-lamp while burning. The physiologist may employ it to ascertain the weight lost by animals during respiration and perspiration, and the botanist to determine the amount of evaporation from the leaves of a plant; and from these examples others may be imagined.
Stock-taking in science is as indispensable as in business, and there is something like stock-taking in the subject for which the University of Oxford proposes to give a ten guinea medal and about five guineas in cash: it is 'The History of the successive Stages of our Knowledge of Nebulæ, Nebulous Stars, and Star Clusters, from the time of Sir William Herschel.'
The Royal Astronomical Society have published an account of observations of Jupiter's satellites made by Mr Todd of the Observatory, Adelaide, under remarkably favourable circumstances. Sometimes the satellite, when on the point of occultation, is seen apparently through the edge of Jupiter, 'as if the planet were surrounded by a transparent atmosphere laden with clouds.' In a subsequent observation, 'the shadow of the third satellite, when in mid-transit along a high northern parallel, appeared to be visibly oval or flattened at the poles.' On several occasions, as Mr Todd states, he has been surprised at ingress of shadow by the marvellous sharpness, the minutest indentation of the limb being at once detected. One night he saw the second satellite, as it emerged from behind the planet, immediately pass into the shadow, then reappear within a few minutes of the reappearance of and close to the first satellite; and the two thus formed 'a pretty coarse double star.' This must have been a very interesting sight. And there were times when the astronomer was much impressed by the sudden and extensive changes in the cloud-belts of the planet, as though some storm were there in progress, changing the form and dimensions of the belts in an hour or two, or even less. After reading this, may we not say that the observer at Adelaide is remarkably fortunate?
The fall of exceedingly minute mineral particles in the snow and rain in regions far away from dust and smoke has been accepted as evidence that a so-called 'cosmic dust' floats in our atmosphere. Some physicists believe that this dust is always falling everywhere, that the bulk of the earth is increased, and that the phenomenon known to astronomers as acceleration of the moon's motion is thereby accounted for. Iron is found among the particles, exceedingly small and globular in form, as if they had been subjected to a high temperature. Recent spectrum analysis has led to the conclusion that the light of the aurora borealis may be due to the presence of these particles of iron in a state of incandescence. In a communication to the Vaudoise Society of Natural Sciences, Mr Yung assumes that this dust, coming to us from celestial space, will be most abundant immediately after the showers of shooting-stars in August and November; and he purposes to collect masses of air on great heights and treat them in such a way as to eliminate all the cosmic dust which they may contain. His experiments lead him to believe that the particles are in much greater quantity than hitherto supposed, and that they play an important part in the physics of the globe and in the dispersion of solar light. Dr Tyndall has shewn that a perfectly pure gas has no dispersive action. The cosmic dust floating in the upper regions of the atmosphere would account for the luminous train of meteors, and for certain phenomena observed by means of the spectroscope. A long time will of course be required for the quantitative experiments, but they will be of great interest to astronomers as well as to physicists generally.