Here, again, we see an invention of the highest order in each of the three essentials--conception, development and production. No invention exists of a higher order. As to their use and usefulness, we are most familiar with them in moving pictures. Whether it is for the public good to produce so many shows for idly disposed men and women to spend their time in looking at, is perhaps a possible subject for enlightening discussion. But the moving picture is used for many purposes, especially for purposes of education and research, besides that of mere amusement, and will unquestionably be so used, more and more as time goes on. One of its most obvious spheres of usefulness is in making photographs of movements that are very rapid, and then analyzing and inspecting those photographs when presented very slowly, and when stopped. Another is in taking photographs of successive situations that have occurred at considerable intervals of time, and then presenting the pictures quickly, and thus showing a connected story. By dealing in this way with historical incidents, we can get a realization of the interdependence of those incidents that we cannot get in any other way, and see how cause has produced effects, and effects have come from causes. Similarly, the work of building any large structure can be shown by presenting rapidly a series of photographs taken at different stages; and so can the growth of a plant or animal, and almost any kind of progress. Let us impress on our minds the fact that if we read any book, or witness any occurrence, or listen to any argument, or receive any instruction of any kind, the only value comes to us from the pictures made on our mental retinas and the permanence and clearness of the records impressed. Thus, any means that can impress us quickly with the most important pictures must be of the highest practical value, both in prosecuting studies of events, and in gathering conclusions from them. In fact, the kinetograph and the kinetoscope are simply Edison's imitation of the operations carried on inside the skull of each of us; for we are continually taking moving pictures of what we see and hear and read and feel; recording them on our own moving sensitized films, and bringing them before our mental gaze at our own volition and sometimes in spite of it. In 1890, the author of this book patented "A Method of Pointing Guns at Sea" that has been adopted in all the great navies, under the name "Gun Director System." In 1891 he patented a modification under the name "Telescopic Sight for Ships Guns." These two inventions are used in every navy in the world, have increased the effectiveness of naval gunnery immeasurably, and have, therefore, been important contributions to the self-protectiveness of the Machine.