Table rockets are so-called because for firing them a table, or some other plane surface, is used. (PL VI., fig. 8.)
A case of 15 lines is commonly employed. This is placed upon a base without a spindle, and a plug is driven to the bottom. The case is then loaded with the composition hereinafter described. Twenty blows of the mallet are struck for each charge. The case is closed at the top with another plug. To give greater facility for choking, about half the length of the empty case above this plug is pushed inward over it, and crushed down upon it by blows of the mallet. The case is then choked and tied just above the plug. The excess length above the choke is cut off with scissors. The circumference of the rocket is divided into four equal parts by drawing four parallel lines from one end of the case to the other. One of these lines is called the superior, and that opposite it is called the inferior. The other two lines are called the laterals. A hole is pierced in each of these laterals near the plug that closes the throat of the rocket. Four other holes are pierced on the inferior line at equal distances, by which means the length of the case is divided into five equal parts. The six holes should be made with a gimlet having a diameter one-quarter that of the interior of the rocket. The holes should reach to the composition, without penetrating it. They are filled loosely with powder. A match is then placed along the line of the four inferior holes, and another match extends between the two lateral holes. Both these matches are held in position at each of the holes by a bit of wet priming, and they are covered with strips of pasted paper.
When the paper has dried, a groove is made in the middle of a small stick, having the length of the rocket, and this stick is attached crosswise over the middle of the inferior line. The notch serves to contain the match, which otherwise would prevent the stick from proper contact with the case. The stick is held firmly in position by winding with wire. String can not be used, since it would be burned during the discharge. The purpose of this stick is to maintain the rocket in its proper position.
The rocket is fired by a small piece of match, which is pasted to the fuse that communicates with the two lateral holes.
The effect of this rocket is first a rotation, so that it forms a revolving sun on the table where it is placed for firing. This continues until the fire, which has begun with the lateral holes, is communicated to the four holes underneath. The rocket is then raised in the air, but the gases, forcing their passage through the lateral holes, continue to give a rotary movement. Thus, there is shown a sun which both revolves in the air and also raises itself to a horizontal position. The result is especially pleasing when the rocket is charged with Chinese fire.
A similar method is employed with four rockets. These are fastened on a wooden cross, each pierced with one lateral hole and two inferior holes, or even three, following the length. The cross fulfills the function of the stick placed at right angles as above described.
Such rockets may be made either large or small as desired. Care must be taken, however, to diminish somewhat the force of the composition used, as the size of the rocket increases, or to increase its force correspondingly as the diameter of the case diminishes.