No. 11.—Stratagemata, by Hilary of Neapolis.

IN THE ANNALS of lost books, a special interest attaches to those that were deliberately suppressed rather than simply lost to the ravages of time. Such a one was Hilary’s Stratagemata, which dealt with various stratagems that could be used to defeat an enemy. It was suppressed by order of the emperor Vespasian because he considered the stratagems contained in it to be too inhuman for civilized Romans to practice against their enemies. Our only knowledge of this book comes from a few notices in Pliny’s letters, in one of which he describes several of Hilary’s stratagems:

A bladder, which, filled with water, may be hurled or tossed at the enemy general by a skillful ball-player. The sudden drenching will throw him into confusion.

A set of disembodied teeth, which, by a clever mechanism first devised by Hero of Alexandria, are made to chatter with a great deal of noise. They may be placed along the road to strike panic into the enemy’s infantry.

A kind of ink that becomes completely invisible some time after it has been applied to papyrus. It may be used in the writing of treaties which one has no intention of honoring.

An arrow which, by a clever contrivance, is fitted over the head in such a way that the wearer appears to have been shot through the skull. It will terrify enemy soldiers with the belief that the men they are facing are immortal.

A cushion may be made with a concealed bladder, inflated in such a way that, when pressure is applied, the breath escapes with a sound indistinguishable from that of a severe attack of flatulence. The demoralizing effect of several such cushions placed on the chairs of the enemy generals cannot be overestimated.

A jar or small amphora which, when the lid is removed, releases a number of artfully made snakes in such a way that they appear to leap toward the holder of the jar. It has been known to cause attacks of apoplexy in enemy officers.