Fixed fires are those retained in their original position on the ground during the period of their discharge, but within the limits of their own place they may be given a considerable variety of movements. Jets used for such fixed fires are made in a variety of ways, according to the preference of the manufacturer. One method employs sections of cane, which is wound very closely with tarred string to within an inch of the top. Such a jet is loaded solidly with a rammer and mallet, which vary in size according to the caliber of the cane. Each sucessive charge is struck 14 or 15 blows with the mallet for the larger jets. A jet 3 inches in length contains three or four charges, one 4 inches in length has four or five charges, and so on. The cane is pierced to permit the introduction of the fuse, and loose powder is added in the space left for it above the charge. When such a jet is fired, a long tongue of flame darts from the mouth with vehemence. The force with which the fire issues is such that when the jet is mounted on a movable axis, it causes this axis to turn, with a speed proportioned to the liveliness of the composition. On this account, for revolving jets a quick-burning mixture is employed, while a slow composition is used in loading those jets that are to remain immovable. For the same reason in connection with the movement, the revolving jets are fashioned with a smaller orifice at the top than are the fixed pieces.

The different effects for such jets are controlled easily by the method of mounting and the arrangement of the fuses so as to control the combustion and to direct the energy of the burning gases in any required direction. The number of diverse forms in which such jets are attached is, in fact, only limited by the ingenuity of the artificer, and the special sorts are listed by manufacturers under many different names. Among the compositions used for loading fir© fountains of small size are the following:

Common Fire

1st

2d.

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

100

16

Charcoal (hard wood) .................................

---

3

Sparkling Fire

1st

2d.

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

16

16

Iron filings........................

2

-

Steel filings................................

----

3

1st.

2d.

3d.

4th.

5th.

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

16

16

16

18

16

Iron wire............................

4

3

---

- -

---

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

---

1

l

2

4

Steel filings......................

----

- -

3

5

3 1/2

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

---

--

1

1

2