| Show scientific miscellany in his tests of the Tur binia the ahe first vessel using the compound steam turbine the honorable charles A parsons has experienced the not wholly unforeseen difficulty ot oi excessive speed of the screws the effect of this was shown by an ingenious experiment model screws were revolved in a bath ot of hot water a revolving mirror 0 oh n the screw shaft reflecting the light of an electric arc to the screw at one point only and thus causing the shape and growth of the cavities to appear as plainly as it stationary A cavity or blister first formed a little behind behin the leading edge and near the tip of the blade As the spee speed d of revolution increased this cavity enlarged in all directions until at a speed corresponding to that ot of the Tur binias propeller it covered a sector of the screws disc of goo 90 and at a little higher speed nearly the w whole hole energy ot of the screw was expended in maintaining a vacuous space the turbine ultimately used idof is of the three stage compound order each expansion having its separate motor working its own propeller shaft the vessel which is loo feet long 9 feet beam and 44 tons displacement has exceeded 31 knots the energy developed being 1576 indicated horse power with a steam consumption of 1586 pounds per horse power hour the total weight ot of machinery etc is 22 tons the results seem to be unprecedented for a vessel of the size although it is recognized that improvement of motor and deduc reduction tion of revolutions are necessary to make the system practicable in his early experiments with the electrified high vacuum tubes which the X rays have brought so conspicuously to notice crookes observed a singular blackening of diamonds under the molecular bombardment in the tubes doissan has lately investigated the black layer it brov s to be graphite and for it its s P production ro from the diamond must have required a temperature of C fatty acids doubtless of beef or mut ton have been found in the egyptian tombs of dating from before the first dy nasty together with a cosmetic of lead sulphide and fat highly magnetic spots apparently having no connection with the general magnetization of the earth are found at daffe different rent places in the rocks it has been suggested that these points may have been magnetized by lightning this theory has been singularly barly confirmed by the researches of doc doctor t or G Folge who has found precisely similar magnetic points and zones in the remains of ancient walls and buildings in the roman campagna the tact fact that the magnetic spots extent over aJ adjacent jacent stones and even to the mortar disproves di proves the idea that they may have existed in the stone before use for building cracks down the walls moreover are visible marks that the lightning seems to have left in some cases right handedness so long a scientific puzzle is believed by doctor G V to be a result of the distribution of the weight of the viscera in the thorax and to have had its origin with our four limbed ancestors long before they began to stand on their hind legs i for oratorical or other purposes much the greater weight of the viscera i h oa i the left side this causes the stab stability clity i of the anima animals ls body to be more upset 1 by lifting its left paw than its right and the right paw therefore is the one usually selected selected for independent use A v creeping child would for the same reason use the right arm for purposes independent of locomotion the system ot of accumulators designed for street railway use by herr paul ribble of berlin has for its essential feat feature carrying plates of celluloid inclosing the lead plates and provided with a number of openings the edges of which form the supports for the active material in the form of a special paste this form of construction is claimed to ensure great durability in spite of great varia eions of load A streetcar street car bat battery tery on i this system consists of cells bavine having a total weight of about ax 2 tons and w supplying an equivalent of 40 40 horse pow er fur a run ol of twe twenty nty hours without re charging sp for protecting the eyes from J sp sparks arks flying aplin splinters and the like arel are 1 made by doctor of berlin berli 0 itom from rings gs gelat oid an elas elastic tic i transparent material which can be hard 4 ened in amyl acetate if broken the substance does not splinter like glass it does not dot con condense dense moisture on its sur I 1 1 face does not become so hot as glass near a fire and is uninflammable I 1 the mhd latest determination of the limite limits of audition according to lord R rayleigh aylein gives 24 complete vibrations a second for the lower limit and about tot to r the upper both limits however are ill defined depending largely on the 1 vi vigor 9 or ot the vibration and the individual experiments seem to s show how that a bibra tion having an amplitude of only 8 aioo 3 ot of a centimeter can still effect til the ear such a vibration being times smaller than the smallest object visible blek 1 in any possible microscope or stated in another way the ear is so sensitive that it distinguishes differences of pressure I 1 times less leis than the residual pressure J of the best vacuums which is measured 1 in in millionths 0 or r less of an atmosphere the propagation of strong sounds is doubtless greatly hindered by atmos I 1 pharic refraction this would seem to explain why some 63 horsepower horse power trinity house sirens can scarcely be heard two miles away although calculi cal cula tion from the law in inverse squares would seem to prove that the sound k should travel 1500 miles in the 1 tion of pitch a good observer can distinguish a difference of only a third of a vibration per second this is when the notes are sounded consecutively if sounded simultaneously there is scarcely sc arcey any limit to the minuteness of difference revealed by the beats the feeblest grave sound with a remarkable power of obliterating and masking a high one is able to make itself heard very verv strikingly in spite of high ones the ordinary electric spark in a lengthened torm form a synonym for inconceivable cei vable rapidity is too slow for modern requirements in his bis attempts to photograph flying bullets by the light of the spark protessor professor C vernon boys found that the double flash produced lasted somewhat iless less than the of a second giving only blurred pictures he therefore shortened the spark instead of wire terminals he be used two very thick broad bands of copper not more than two inches long which reached round opposite edges of the photographic plate in such a manner that a spark resulted when electric junction was effected by the passage of the bullet the spark was thus shortened to about i 11 booth of a second inthis in this time a bullet from an ordinary magazine rifle could not travel more etian one five hundred eth of an inch and good and sharp pictures were obtained the curious conclusion has been reached by fournier in a london electrical journal that only experiments peri ments in physics are possible and over 2000 have been already performed |
