In 1890, Krag-Jorgensen invented the famous rifle of that name. In the following year, Branly invented the coherer mentioned on page 305, and Parsons invented his rotary steam turbine. The steam turbine was an improvement over the reciprocating steam engine for many classes of work, great and small. The first steam engine invented by Hero was a rotary engine, but it was of course, most uneconomical of steam. The first steam engine that was really efficient was the reciprocating engine produced by Watt. The greatest single defect of rotary engines has always been the loss of steam in going by the rotating parts without doing any work, a defect existing in only a small degree with the closely fitting pistons of reciprocating engines. In the turbines invented by Parsons and others about the same time, wastage of steam was prevented by various means that need not be detailed here, and smooth motion of the rotary engine at the same time secured. The greatest benefit accrued probably to ocean steamships, in which the absence of vibration, and the saving in weight, space and number of attendants required were features of great practical importance. About 1890, Edison invented the kinetograph and kinetoscope, after a long series of investigations and experiments. These followed the experiments made by Dr. Muybridge some years before, in which he had taken many successive pictures of horses at very short intervals, by means of as many separate cameras, (twelve pictures in one stride for instance), and afterwards reproduced them in such a way as to show horses in rapid motion. They came also after Eastman's kodak, in which pictures could be taken successively, on a traveling film. In the kinetograph, only one object glass was used; and the film was drawn along behind it in such a way that, at predetermined intervals, the film was stopped and a shutter behind the object glass or lens was moved away, and a picture taken. The moving mechanism (at first the human hand) continuing in motion, the shutter was closed and the film was moved along a short distance, so as to bring another part behind the object glass. Then the same operation was repeated--and so on. In the kinetoscope, the operation was reversed, in the sense that the pictures taken were presented successively to the eye of the observer. In the first form, the observer looked at them through a peep-hole: but in the latter forms, the pictures have been thrown upon a screen--somewhat as from a magic lantern, and become the "movie" of today.