Serpents not exceeding two inches in length, and a quarter of au inch in diameter, may also be made of powder alone ; but it must be rationed hard, in a wooden mould. The case requires no choke in this instance, so that it may be filled at the mouth. The Chinese serpents are made in this manner; and if furnished with a verrslender and straight splinter of bamboo, or fir, they will ascend like sky rockets, vertically. As they occupy very little room, even with the sticks, flights of them may be easily introduced into such or namental fireworks as are not to be viewed From a great distance.
But serpents may be made of a much larger size than this \viten large sky rockets are used, or whets they are to be discharged from powerful. mortars, or exploded out of air balloons. They may also be used of large size for the most common purposes, as for small pots on the ground, or for being attached to gerbes, or to line rockets, or to be used as water rockets. There is in fact no limit to them, except the com fort and safety of the spectators, among whom they are apt to fall when the crowd is too near the place of exhibition. The operator will of course be guided by this circumstance; as accidents by which persons may be injured are in every way blamable and discreditable to the operator.
For such large sizes the cases may go as far as eight inches it length, or to the size of a quarter of a pound sky rocket. These must be filled with a sky rmIct composition, and boared in the saute manner, and they must in fact be considered as sky rockets without sticks. When of large size, they are very violent in their mo tions, and hence the caution which we have just given against using them in crowds, or near to spectators.
Whenever serpents become large, their flight is very much improved by adding a stick to them. This need not exceed one or two lengths of the rocket, but the longer it is, the more nearly will the serpent become a sky rocket in its flight. The effect of those with sticks is good, when used on the ground, as by this means they ascend to a conisderable height before they begin to serpentize. They are not difficult to manage, as the firing case may easily be made long enough to imbed the sticks, as far as to the mouths of the serpents. But in this case a quick match from each must be let down upon the exploding charge; and the whole of the ser pents may then be collected above, by means of a slight piece of pasted paper, into a cylinder and cone, so as to protect them from all injury till the time of using them is arrived.
Having thus finished with the simplest class of fire works, we shall proceed to wheels, as first in the order of complication.
Of ivkeels.
These, in all their varieties, form the most showy and atnusing kind of firework in the whole catalogue, and one which is in many respects much cheaper than others of less brilliancy. All of them depend upon the principle of recoil, until they become much complicat ed and intermixed with other works, so as to be required to carry additional weight ; when the assistance of re volving machinery becomes necessary, as we formerly suggested. In their next simple state they admit of considerable variety, depending on their dimensions, their velocity, and the quality of their fires. But they also admit of so many modifications, by which they pass gradually into the second class of complicated fire works, that we must treat of each variety under separate beads.
It will be necessary here to repeat some of the gene ral remarks formerly made, with the addition of others, for the artist's government. Where they are to move by their own force the cases require to be choked and driven just as for rockets. But it is not often neces sary to bore them, unless a very great velocity or force is wanted ; in which case they must be driven on the spindle in the usual manner. Supposing that a wheel, formed of cases an inch or more in diameter, is wanted, as there is a considerable weight to be brought into motion from a state of rest, it may be necessary to make the case, which is first intended for lighting, with a long bore, or to make it, in fact, a sky rocket. Thus, there will be gained so great a velocity at the begin ning, that a very small additional force in the succes sive cases will he sufficient to maintain the motion to the end. The second and third cases may, therefore, pass without boring, or even the whole ; or else a short bore, varying from one diameter to two or more in length, may be used ; or, lastly, the cases may alternately be bored or left solid; but on all these points it is only necessary to give the general principles, as the artist must after all be guided by his own discretion, and by the nature of his particular views.