When we come thus to consider the gyrocar as a vehicle in which all of us may soon have an opportunity to ride, there is one practical question that is sure to present itself to the mind of almost every reader. What will be the effect should the electrical power that drives the gyroscopes give out at a critical moment, as, for instance, when the car is just crossing a gorge or river on a cable? Mr. Brennan's ingenuity has anticipated this emergency. The gyroscopes that balance his cars operate in a vacuum, and all the bearings are so well devised as to give very little friction. The wheels will continue running for a considerable time after the power is shut off. The large gyroscopes of the commercial car, it is estimated, will perhaps require two hours to attain the highest rate of rotation, but they will then continue revolving at an effective speed for some hours, even if no further power is applied to them.
It may be said, too, that the gyrocar is provided with lateral legs that may be let down in case of emergency or when the car is not in use, to avoid waste of energy in needless running of the gyroscope. All in all, it would appear that the dangers of travel in a gyrocar should be fewer than those that attend an ordinary double-track car; and Mr. Brennan believes that it will be possible, with the aid of the new mechanism, to attain a speed of one hundred and fifty, perhaps even two hundred miles an hour with safety.
TWO VIEWS OF MR. LOUIS BRENNAN'S MONO-RAIL GYRO-CAR.
The gyroscopic mechanism for automatically balancing the car is contained in the cab-like anterior portion. The platform of the car maintains its equilibrium even when the forty passengers are crowded on one side, as shown in the upper picture.
VIII
THE GYROSCOPE AND OCEAN TRAVEL
IT must not be supposed that Mr. Louis Brennan's remarkable monorail car affords the first illustration of an attempt to make practical use of the principles of gyroscopic action. The fact is quite otherwise. The idea of giving steadiness to such instruments as telescopes and compasses on shipboard with the aid of gyroscopes originated half a century ago, and was put into fairly successful operation by Professor Piazzi Smyth (in 1856). More than a century earlier than that (in 1744), an effort was made to aid the navigator, by the use of a spinning-top with a polished upper surface, to give an artificial horizon at sea, that observations might be made when the actual horizon was hidden by clouds or fog. The inventor himself, Serson by name, was sent out by the British Admiralty to test the apparatus, and was lost in the wreck of the ship Victory. His top seemed not to have commended itself to his compatriots, but it has been in use more or less ever since, particularly among French navigators.