FLYING AND FLYING-MACHINES. 347 



Scotland. During the voyage to Teneriffe (where, it 

 will be remembered, his well-known Astronomer's Ex- 

 periment was carried out), he tested the power of the 

 gyroscope in giving steadiness, by causing a telescope 

 to be so mounted, that the stand could not shift in 

 position without changing the axial pose of a heavy 

 rotating disc. The disc was set in rapid rotation by 

 the sailors, and then the Professor directed the telescope 

 towards a ship on the horizon. A fresh wind was 

 blowing, so that everything on deck was swayed in 

 lively sort by the tossing vessel ; nor did the telescope 

 seem a whit steadier the motion of objects round it 

 giving to the instrument an appearance of equal 

 instability. But the officers were invited to look 

 through the tube, and to their amazement, the distant 

 ship was seen as steady in the middle of the telescopic 

 field as though, instead of being set up on a tossing and 

 rolling ship, the telescope had been mounted in an 

 observatory on terra firma. The principle of the 

 gyroscope has also been used for the purpose of so 

 steadying the stand of a photographic camera placed 

 in the car of a balloon, that photographs might be 

 taken despite the tendency of the balloon to rotate. 

 As applied to flying-machines, the gyroscope would 

 require to be so modified in form that its weight would 

 not prove an overload for the machine. This is practi- 

 cable, because a flat horizontal disc, rotating rapidly, 

 will support itself in the air if travelling horizontally 

 forward with adequate swiftness. In other words, 

 since travelling-machines must travel swiftly, the gyro- 



