A second way is to drill a hole through the beam, through which the thread or elastic that binds it to the rod can pass. The best way perhaps is to make the hole in the beam large enough for rod P Q to pass through, and then bind it to the rod with elastic or thread or, if a large model is being made, catgut. (A jeweller is generally ready to give away a small quantity of this.) A barrel, R, can be filed or cut from a small piece of wood or cork, or it may be a small reel.
To work the machine pull the beam down by means of a piece of thread looped on to the hook M and wound around the windlass. When the beam head is down, place the barrel on the fork and keep it in position by rope, S. When the beam head is released, it flies up and the barrel is shot forward.
This trapget or war engine was used for casting Greek fire, with which the barrel was filled. It may interest the maker of this toy to know its composition. In the words of an old writer: "You make Greek fire thus: Take quick-sulphur, dregs of wine, Persian gum, 'baked salt,' pitch, petroleum, and common oil. Boil these together. Then whatever is placed therein and lighted, whether wood or iron, cannot be extinguished except with vinegar or salt."
Fig. 326
Generally this engine had a kind of wooden hood in front to protect those working the machine (Fig. 326). This hood is easily made of stripwood or an old cigar-box. Notice that the stripwood that forms the sides, A B C D, must be longer (extended in diagram to S T), so that strips of wood, 1, 2, 3, 4, 5, can be nailed and glued as in diagram.
The Mangonel, Fig. 327 (an instrument for casting great stones to beat down walls and to slay the enemy), makes an interesting toy.
Fig. 327