GLOBES AND BALLS. 235 



entirely inverted, so that its head begins to point downwards, in 

 order to fall, they will represent a kiinl of fiery fountain. 



If the barrels of several quills, filled with the composition of 

 flying rockets, as above described, be placed on a lar_,e rocket ; 

 when thrse quills catch fire, they will represent, to an eye placed 

 below them, a beautiful shower of fire, or of half frizzled hair, if the 

 eye be placed on one side. 



If several serpents be attached to the rocket with a piece of 

 pack-thread, by the ends that do not catch fire; and if the pack- 

 thread be suffered to hang down two or three inches, between 

 every two, this arrangement will produce a variety of agreeable and, 

 amusing figures, 



SECTION V. 



A Rocket zchich ascends in the Form of a Screw. 



A STRAIGHT rod, as experience shews, makes a rocket ascend 

 perpendicularly, and in a -traight line : it may be compared to the 

 rudder of a ship, or the tail of a bird, the effect of which is to make 

 the vessel or bird turn towards that side to which it is inclined: 

 if a bent rod therefore be attached to a rocket, its first effect will 

 be to make the rocket incl ne towards that side to which it is bent; 

 but its centre of gravity bringing it afterwards into a vertical situ, 

 ation, the result of these two opposite efforts will be that the rocket 

 will ascend in a zig.z g or spiral form. In this case indeed, as it 

 displaces a greater volume of air, and describes a longer line, it 

 will not ascend so high, as if it had been impelled in a straight di. 

 rection ; but, on account of the singularity of this motion, it will 

 produce an agreeable effect. 



CHAP. VII. 



OF GLOBES AND FIRE BALLS. 



W E have hitherto spoken only of rockets, and the different kindi 

 of works which can be constructed by their means. But there are 

 a great many other fireworks, the most remarkable of which we 



