below the mean point would largely make up the discrepancies in distribution and density.

On account of errors of gun and fuse the dispersion of several rounds is also a little greater. Experiments have shown that volley fire, two or more rounds per gun, will cover a beaten zone about 250 yards deep at 3,000 yards range, and 150 yards deep at 4,500 yards.

While it is possible, then, to deliver an accurate fire at a range of 7,000 yards, the effectiveness of shrapnel fire diminishes with the increase of the range from 3,000 yards on. At extreme ranges the possibility of putting permanently out of action an opposing battery, concealed from view and having its personnel protected by shields, is very remote.

The battery may be temporarily silenced or forced to slacken its fire, but during the calm after the squall its power will be found little impaired, for at such ranges the shrapnel has very little sweeping power and consequently the danger space is small. It must almost light on an object to injure it.

Experimental Tests.-Experimental firing in 1906 established the following facts concerning accurately adjusted shrapnel fire (3 mils height of burst) at a range of 3,000 yards:

19% of the shrapnel will burst on graze.

20% will burst less than 9 yards in front of the target, all of which distance is danger space for men standing.

50% will burst less than 66 yards from the target; danger space, 45 yards.

75% will burst less than 111 yards from the target; danger space, 84 yards.

95% will burst less than 163 yards from the target; danger space, 103 yards.

95% will burst less than 190 yards from the target; danger space, 118 yards

99% will burst less than 242 yards from the target; danger space, 149 yards.

From these figures it may be determined what area in front of an objective point is searched by well-directed shrapnel fire. There will be premature bursts much further from the target than shown by the foregoing figures which would endanger the advance of troops being supported by the fire.

The interval between the point of burst of a shrapnel and the target is called the interval of burst. It is plus (+) or minus (-) according as the shot is over or short. The distance of the normal burst from the target is the mean interval of burst, and depends upon the range, and, therefore, the height of the mean burst.

The following facts have also been ascertained by experiment.

The time fuse acts with a considerable degree of uniformity. The error of the fuse is, however, much too great. At mid-ranges about 20% of the shrapnel fired will burst on graze even though the fire has been well adjusted. They are then, as a rule, quite ineffective. Moreover, about 10% to 15% will burst so high as to be almost ineffective. Thus, due to the error of the fuse, about 30% of the fire is practically ineffective at favorable ranges and 30% of the ammunition is wasted by reason of a defect in one part of the projectile.

Artillery efficiency is measured by its ability to burst effective shrapnel at the target, and for this purpose the whole expensive plant in men, animals and material is maintained. Assuming that the personnel is capable of performing its part perfectly, the measure of efficiency would still depend upon the accuracy of the fuse. The fuse is the weak point in the present system. The "hooded-vent" fuse, with a reducer error, has been adopted since the tests of 1906; but the error is not much less than that of the earlier type, and the foregoing figures are practically live.

About 5% of the shrapnel cases burst in air.

Shrapnel seldom break up in the gun or burst at the muzzle. About of the pellets are ineffective at all ranges.

The normal height of 3 mils gives the most favorable distribution of effect, when targets of all kinds are considered, that is, the density of fire approaches most nearly to one hit per unit of surface.

A lower burst gives very dense effect over a restricted area, but the bullets are not used economically; two or three being expended to do the work of one.

A greater height of burst increases the width and depth of the bullet pattern, and permits utilizing the full effective range of the bullets; but the density of fire decreases, and the proportion of ineffective hits increases very rapidly with the height of burst. Hence, the area is not effectively searched. It is to be noted, however, that against deep, broad targets it is preferable to have the mean height of burst a little high rather than too low, as the former gives a better distribution of the effect.

Bursts on graze are practically ineffective unless within 10 yards of the target.

The projectile will ricochet up to 3,700 yards and burst after graze is obtained. At longer ranges the projectile does not seem to ricochet, but enters the ground and bursts after penetrating several feet, creating a large crater. There were instances in the Russo-Japanese War of shrapnel penetrating 9 inches of masonry before bursting.

High Explosive Shrapnel.-A more powerful shrapnel than the one now in general use in our service is being perfected. It is known as a single-type projectile, that is, it is designed to be used either as a shrapnel or as a high explosive shell. This is accomplished in the following way: The matrix in which the pellets are imbedded, instead of being an inert substance, or merely a smoke-producing material as in the common shrapnel, is, in itself, a high explosive. This high explosive, however, is very insensitive, so that, when the shrapnel is discharged in the air by the burning of the small black powder charge in its base,

the high explosive is not detonated or exploded. In order to cause the detonation of the matrix when the projectile bursts on percussion, the head of the projectile has a chamber containing a charge of high explosive. When the projectile strikes a resisting object, the percussion element of the combination fuse detonates the charge of high explosive, which, in turn, detonates the high explosive matrix. If the projectile bursts in air the head is blown off, and on striking acts as though it were a small high explosive shell.

This projectile, if perfected, will possess many advantages, as the difficulties growing out of several types of ammunition would be eliminated and the vexing question of the relative proportions of shell and shrapnel would no longer present itself.

High Explosive Shell.-At present, shrapnel and shell are both issued, the former for animate and the latter for inanimate objects. The present shrapnel bullet has not sufficient power to destroy material; and on account of the flatness of the trajectory and the small angle of the cone of dispersion, it cannot reach troops in any but the lightest entrenchments. Hence, the other type of ammunition, or the steel shell, is issued, holding about two pounds of the service high explosive. This is burst by a detonating percussion fuze.

On detonation of the filler, the shell breaks up into 500 to 600 fragments, and it has been proposed to use it instead of shrapnel against troops in entrenchments, for if it bursts at the proper point, by means of a time fuse, the fragments fly in all directions and search cover in a manner impossible to shrapnel. No satisfactory results of this nature have been obtained, however, and so no time-shell is issued in our service.

The explosive used in the H. E. shell is a secret compound, and combines extreme safety in transportation with extreme certainty and force of action. The shell complete weighs the same as the shrapnel, 18.75 pounds. The projectile in each case weighs 15 pounds; the high explosive power of the shell compensating for its lightness in metal.