Caduceus Rockets.
4. CADUCEUS[13] ROCKETS.
If two Rockets be fixed obliquely on the opposite sides of a rod, they will form in their flight two spiral lines; they must exactly balance each other on the opposite side of the rod, or they will not rise in a vertical direction. Both ends of the Rockets must be choaked close, without either head or bounce, for a weight attached to them would obstruct their ascent. The rod proper for these Rockets should be square, and at top equal to the breadth of a rod for a common single Rocket, of the same weight as those you intend to use, and long enough to be in equilibrium, when suspended one length of the Rocket from the cross piece A, [fig. 24], whose length should be equal to about seven diameters of the Rocket, and placed about six diameters from the top of the large rod; so that when fixed, they will form with the perpendiculars an angle of about 55 or 60 degrees.
The heads of the Rockets should be placed on the opposite sides of the cross piece, and their ends on the same of the large rod; then their mouths must be connected by a leader, which, when they are fired, must be burned through the middle, and then they will exert their ascending forces at the same time.