The Chinese and Japanese sometimes have little messengers that are released when a punk burns down so as to burn off a supporting thread. This might be applied to parachutes too. Another good device but which is not self-propelling on the upward trip is the trolley car, Fig. 144. The car is pulled up the kite line to a trip, when it is released and returns by gravity. The pulley block is tied into the kite line, Fig. 145. The line below the block passes thru the car under a little roller on the inside of the car at each end. The car can be made up of any light material, but need not be as light as self propelled devices, the weight being an advantage on the downward run. The line that pulls the car up passes around the grooved pulley, thru the guides in the pulley block and one end goes to the car while the other goes to the operator. A release is necessary, and perhaps a little sharp blade like a safety razor blade will be as effective as any, Fig. 146. In Fig. 147 another trip is shown in which a wire is bent, as at _a_. This wire passes up thru the upper portion of the roof at _b_, and passes thru screw-eyes _c_ and _d_; _d_ is bent forward. The lower portion of the wire as represented is much longer than the upper, and when it touches the pulley block is pushed back, and the shorter portion is pushed back of screw-eye _d_, which releases the small ring, _e_, to which the pulling line to the operator is attached, and also sets free the car to run down the kite line. This last is not a difficult attachment and seems a little more scientifically mechanical. [Illustration: FIG. 146.] [Illustration: FIG. 147.] There are other ways of effecting the release. A good pulling kite is necessary, as in the excitement of pulling up the car, more strain is put on the kite than one would realize. If a race is on, a fishing reel would be an advantage. This last messenger is not limited to the street car, but the form might be a locomotive and train, an automobile or an air ship. The latter might have adjustable wings so as to be open to the breeze on the up trip and so be self propelling as in the yacht, and by releasing that which holds the wings open, they will close up, and the messenger would be ready for the down trip. In the messenger races, it is necessary to measure the string. At a tournament it is necessary to do this beforehand. It is not necessary, but more interesting, to have all the contestants operating at the same time. In case all cannot operate together, each can be timed. Some very comical devices might be devised as messengers, not so much for speed as for amusement. Certain motions might be developed that would add much to the entertainment of all. CHAPTER IX. MOVING DEVICES.