The lances have a long cylindrical case, loaded individually with a number of charges, which produce fires of various colors. Such pieces are adapted for purposes of illumination in the representation of temples, palaces, and the like, for elaborate pyrotechnic displays. The cases for these are made from paper of light weight, and since its strength is not sufficient to withstand the pressure of a rammer in loading, it is customary to use a sort of funnel, which extends its tube within the length of the case, closely fitting it. The charges are poured into the funnel and duly tamped, and, after the loading has been completed, the tubing is withdrawn. These lances may be of any desired size. There is nothing in the construction of them that requires explanation, beyond the one distinctive feature concerning the use of the funnel in charging.

Bengal lights are usually of the same character as the lances in the matter of the charge, but they lack the length of the latter. They are made with a diameter of two centimeters or more.

The difference in height between the lances and the Bengal lights requires a corresponding difference in the mixtures employed for loading them. It is necessary that the composition for the lances should be somewhat lively, that for the Bengal lights somewhat slow. It is required also that the composition for the lances should be of a sort leaving the smallest possible residuum from combustion, since an accumulation would choke the orifice of the tube, and the resulting flame would be rendered uneven and lacking in brilliancy.

Care must be taken in loading both the fire lances and the Bengal lights to observe a definite order in placing the successive charges within the case. The preference is to give first place to the composition producing a white flame. This should be followed in order by red and then green. After the green may come violet or blue or yellow. The green should not be next to the white, and it should never follow the red, because in such case the effect of the green would be changed to a light-blue tint. The order of charging may take any one of the three following forms, or it may be varied as desired within the limitations already suggested concerning the green light:

White, violet, green, red, white. White, blue, green, red, white. White, yellow, green, red, white.

The compositions for the colored lights displayed by fire lances are illustrated by the formulas that follow:

White

Niter........................

33

Sulphur.......................

11

Powder.......................

2

Antimony...... .......

5

Yellow

Chlorate of potash,.................

4

Sulphur.................

2

Bicarbonate of soda...............

1

Nitrate of barium...........................

1/2

An alternate formula is:

Nitrate of sodium....................

12

Sulphur......................

5

Charcoal...........................

2

Green

Chlorate of barium..........................

3

Shellac..........................

3 1/2

Nitrate of barium..............................

4

Black smoke..........................

1/2

Blue

Chlorate of potash ......................

8

Sulphur................

3

Ammonium sulphate of copper .......................

2

An alternate formula is:

Chlorate of potash..................

5

Oxychlorlde of copper....................

2

Shellac............................

1

Red

Chlorate of Potash.................

6

Sulphur......................

2 1/2

Nitrate of strontium................

9

Black smoke....................

1/2

Shellac.......................

2

Violet

Chlorate of potash.................

10

Shellac........................

3 1/2

Gilder's chalk..........................

2

Verde purgato.................

1/2

Chloride of mercury ......................

1/2

The compositions for the various colors in Bengal lights are illustrated by the formulas that follow:

White

Niter...................

33

Sulphur.............

11

Powder.................

2

Antimony......................

4

An alternate formula is:

Niter......................

12

Sulphur.....................

4

Realgar................................

1

Yellow

The formula for yellow is identical for both the lances and the Bengal lights.

Blue

Chlorate of copper.......................

4

Shellac.....................

1

But the formula of the blue composition for lances may be followed for Bengal lights.

Red

Chlorate of potash..........................

6

Nitrate of strontium...........................

12

Shellac..............................

4 1/2

Black smoke................................

1/2

An alternate formula for the red is:

Chlorate of potash............................

3

Carbonate of strontium ....................

3

Shellac..............................

1

Green

Chlorate of barium..................

13

Milk sugar (zucchero di latte).......................

3

Shellac.................................

1

But the formula given for the green composition in lances may be used also for Bengal lights.

The violet fire for Bengal lights may be obtained from the formula already given for lances.

A variety of the Bengal lights is made of a larger size, reaching sometimes a length of two decimeters. The compositions for these are different, in some instances, from those for the smaller size of lights. The special mixtures for the white and red are here given:

White

Niter.......................

33

Sulphur..........................

8

Powder..........................

1 1/2

Antimony............................

5

Red

Chlorate of potash..................

8

Sulphur.......................

6

Nitrate of strontium...........................

18

Black smoke ........................

1/4

One of the most popular forms of fireworks is the Roman candle, the effect of which is universally pleasing to all observers. It consists simply of a long cylindrical case of especial strength, which is loaded with a lively composition. At regular intervals between the charges of this composition, stars are placed, each resting on a small charge of powder. In loading such a candle, a charge of grain powder is introduced into the case, and duly rammed. On this a star is laid lightly. The star should be of cylindrical shape and of such a diameter that it passes easily within the case. Above the star a charge of composition is poured in, and this is tamped very carefully in order not to explode the star underneath. Then a second charge of powder is poured on the composition, with another star following upon it, then more of the composition, and so on. The loading is completed with a charge of the composition, which reaches to about 2 inches below the orifice of the tube. A small quantity of powder paste is spread over the top of the charge. Some measure of practical experience is necessary for the proper loading of these cases. The quantity of grain powder that should be placed beneath each star varies. The amount is largest near the orifice, and it is smallest at the bottom of the tube. This is due to the fact that the case does not burn along with the composition, but much more slowly. Therefore, the first stars have a limited length of tube through which to issue, and require a larger charge to launch them, while the lower stars have a greater length of unburned tube, and so require a lighter charge, of which the force is augmented by the cylinder's length.