Show film speeds 3 miles I 1 e s minute camera slows down machinery to one two hun dreith of speed detroit feeding movie filin through a camera at the rate of three miles a minute to slow down rapidly mon ing machinery to about one two hundredth of its normal speed is the feat accomplished by C francis jenkins of washington N at the meet ins ing of the society of automotive I 1 en n ginders liere here mr told 0 of tit canic ra rn one of his tat lat et est luent loas anil and how it way lie be ills ai plied to tile lie study of en gines instead of tile hie 16 pictures a set ond oil taken by the ordinary ord luary movie capinera vui cai nera or the lie taken by the llie ultra rapid cai canie rii now frequently aled in lili fi lining athletic adil elic eunis the cie hikes pictures a bee ond tit sit its rule ride it if desben 11 ll inin be speeded sp ridd up even ruttier and take us binally as a second ehni il these are lit in the ardi nary at llie lie speed s of 10 ft second secand lie apparent speed til if llie lie is cot reduced when auken at 3 iw tier second the llie deduc lion of speed Is id aw linn linns s and tit at the higher speeds it Is of course greater uses new system in ali t usual type of motion picture camera the lie filin Is stopped slopped fur for each exposure so that thai it II stops and starts IG 10 limes dinies a second at such high its as those employed in the llie chri atol alne elne cattivera cat tiera tills this Is for the illin would be torn to pieces A further furi hir difficulty dilli culty Is introduced hi baube with will a single lens extremely chort exposures would to be made otherwise Othe ruise tile picture would lie blurred jut ju t as if the object itself were close to the camern camera and intong lit at such a high speed mr jenkins has folded this difficulty by provid IK ig 48 lenses bet in the periphery of a 13 luch iuli disk which litch turns at a speed of resolutions per minute the film aumea back of this disk so that tile llie linage formed by the lenses moves right ulong along walli ith the nim in tact facts the exposures overlap as tile exposure Is begun through one lens before that through the preceding lens Is completed at exposures a second each one is about oue cue twenty five hundredth of a second in length with the rapid lenses used and sensitive film this Is easily sufficient for a ful ly timed negative in bright sunlight in the ordinary movie camera at 18 10 a second each exposure Is about one thirty second of a second in duration mr jenkins calls attention to the good photographic quality to in the ale tures lures uhlon is unusual in such high speed studies tile pictures ure true photographic pictures lis having iving halftone half tone lone alues like other motion pictures not nol mere inere shadowy outlines of grayish lie says they are made out of doors as well as in the laboratory of 0 large subjects or small subjects and from a nio ing i its as readily fis as from froin a fixed platform has photographic quality the camera Is an instrument ment for the hie study of many problems in ili science and engineering soule some of which are not possible of accurate determination in ili any other way some additional applications of this instrument which immediately suggest them bliem sies s ies are a study of gun recoil shell sheh trajectories and plate impacts airplane propellers and landing gear action bursting of balloons and air hose tire action over obstructions water st streams reanis propagation of lame flame engine vale vahe rebound at high speed cam roll er jumping crankshaft blila transformer explosions and circuit breaker arcs shuttle thread knots and bobbin action brake shoe and draft gear application in fact anything that moves too fast for the eye to follow con can be slowed down and can be examined in detail at leisure and repeatedly peat edly |