Over-all diameter

Over-all height

This device consists of a dry-cell battery and an electrical clock with adjustable dial that can be set up to fifty days. By means of a solenoid, the clock is re-wound every five mi-nutes instead of being a constant darin on the battery. This accounts for the relatively long life of the battery, which will stay active an entire fifty-day period and still produce enough current to fire the detonator.

At the end of the set period, the setting dial closes the main switch which puts the de-tonator in series with the battery. A block of approximately one-quarter pound of Italian explosive T-4 is hollowed out to house the detonator, and the block is inserted in the main charge in the space provided.

The main charge consists of approximately fifteen pounds of T-4 in a steel container which is bolted to the clock case. This entire unit is the attached to the sabotage charge.

Figure 248
50-Day Clock