See the preceding section.
Sec. III. Of Fuses with Dead Light.
The feu mort, or dead fire fuse, is a peculiar species of fuse. The difference, between these fuses and the ordinary kind, consists in this, that the eye, instead of being pierced and hollow, is full, and of a hemispherical shape. In both cases, however, the composition is introduced through the small end.
Composition for dead light.
| Meal-gunpowder, | 16 | parts. |
| Ashes of wood, | 9½ | —— |
The ashes must be dried, and run through a sieve. Potters' earth, or clay, will produce the same effect as the ashes.
In proceeding to charge a bomb-fuse that is made of ordinary wood, the eye, or aperture, is first closed with pipe clay, which is well beaten and pressed against the fuse in a small platter; the thin end of the fuse being held upwards. Three lines (3/12ths of an inch) of this earth will be sufficient to stop the communication of any fire. A tube, or trundle, filled with meal-powder, for the purpose of setting fire to the composition called feu mort, is thrust into the fuse, by which it is finally charged. If this charge of meal-gunpowder were to be omitted, the fuse might not be susceptible of ignition; but the quantity never ought to exceed three lines, as the fuse would split by the explosion. When the grains of gunpowder have been well pounded, a trundle or tube, filled with the aforementioned composition, must be applied, and it is finally loaded like the rest.
It must be recollected, that two inches of this composition will last as long as one of the quality, with which common fuses are charged. Before the fuse is driven into the bomb, it must be pierced through with a gimblet of one line in diameter; taking care, that the hole is made precisely through the charge of meal-powder. One end of a priming match must be forced in, and three others be tied to it, which three are to fall upon the bomb, when it lies in the mortar. The particular object to be obtained by this kind of fuse, is to prevent the least trace of fire or light being visible in its projection; so that the enemy may remain ignorant of the range, or direction of the bomb, and not be able, of course, to get out of the way when it falls, or to avoid the effects of its explosion.
These fuses were made use of at the siege of Ham in 1761. The experiments, which were made, in 1792, with this composition, by an artificer belonging to the ordnance board, at Douay, have proved, that it answers every purpose, for which it was invented.
The author of the Manuel de l'Artilleur observes, however, that the advantages to be derived from this invention, are not so great as they first appear. He remarks, that, with respect to the real utility of the fuse à feu mort, if it be considered as tending materially to the defence of any beseiged place, the argument cannot be very forcible, when we reflect, that to gain time constitutes one of the principal means of defence, and that the only way to obtain it, is by retarding the beseigers' operations. These ends are gained by various expedients. Among others, the common lighted fuse conduces not a little: since, during the whole direction of the bomb against the works of the assailants, the attention of the workmen is diverted from their immediate labour; and as long as it continues in its range, much uneasiness is created, because its ultimate explosion and concomitant destruction are unknown. Add to this, that, independent of the confusion that is occasioned among the assailants by repeated projectiles, the bombardier, by means of lighted fuses, is enabled to correct his aim during the darkest night. This kind of fuse has been known for many years, and, it is presumed from these objections to its use, the common fuse has been hitherto adopted.