accidents happen, makes quite an appreciable difference in the cost of a war, without considering the main question of the men's lives. Many inventions arise through a man thinking of an idea and then seeking and finding some application for it. Elsewhere in this book, I give examples of such cases. Here we have an instance of the opposite, for Mr. Calthrop found his thoughts strongly directed in this direction by the death of a personal friend, the Hon. C. S. Rolls, one of the early martyrs in the cause of aviation, not to mention others who shared the same risks and in some cases the same fate. His interest thus aroused, he first studied all the records which could be found relating to parachute accidents, so as to ascertain, if possible, what were the causes of failure. Then he commenced a long series of experiments with a view to removing these causes. Improvement after improvement was tried, unexpected difficulties were discovered and grappled with, the kinematograph was called in to record the movements of the falling objects, a task for which it is far better fitted than the human eye, and after years of this there emerged the finished parachute, automatic in its action, perfectly reliable and a true safeguard, which I am about to describe. The parachute's body consists of the finest quality silk carefully cut into gussets of such a shape that when sewn together somewhat after the manner of the cover of an umbrella, they form a shallow bag, parabolic in section, of that particular shape which the material would assume naturally were it perfectly elastic when enclosing its resisting body of compressed air. At intervals round the edge are fastened twenty-four V-shaped tapes. These are only a few feet long and the lower end of each V-shaped pair is attached to a long main tape. There are twelve of these main tapes, and their lower ends unite in a metal disc from which is suspended the sling and harness by which the man is supported. [Illustration: THE "GUARDIAN ANGEL" PARACHUTE. (1) Shows the airman in the harness by which he is attached to the parachute. By means of the star-shaped buckle he can instantly release himself. (2) Shows the parachute two seconds after the airman has jumped from the aeroplane. In (3) he is seen nearing the ground. (_By permission of E. R. Calthrop, Esq._)] So the twenty-four short tapes form twelve V's to the points of which are attached the twelve long tapes which support the man. The reason why tapes are used in this particular parachute and not cords will be referred to later. In the crown of the silk body there is the usual hole for the purpose of forming the air-rudder to steady the parachute in its descent. And now we can consider the first great feature of this wonderful invention and ask ourselves these questions: "By what means is it made to open?" "What makes it more reliable than others?"