lens and a 50-candképower bulb; the spotlight is more suitable, however, be- 
cause it has a stem that can be used in mounting the light. The beacon should 
be so constructed that the beam may be raised or lowered. This adjustment is 
necessary to accommodate the beam of light to undulations of the terrain. 
The electric current is delivered to the revolving light by means of 
two brushes made of spring brass (fig. 1, D). The lower brush connects with 
the central post of the spotlight and the upper one with an insulated copper 
ring to which has been soldered the spotlight wire leading from the bulb. 
It is powered with a 6-volt phonograph motor making 78 revolutions a 
minute, and the speed is reduced by a set of V-belt pulleys so that the 
beacon revolves three times a minute. By using a different type of moter, 
the beacon can be made to operate on a 115-volt alternating current. Low- 
speed motors adapted te the 115-volt current are also used in electric pho- 
nographs and may be salvaged from such machines, A 6-volt storage battery 
will eperate the beacon 20 to 30 hours on one charging. During very cold 
weather it may be necessary to bury the battery to prevent its freezing as 
the charge runs low, 
The flashing light.is produced by connecting in the circuit near the 
spotlight a "flasher" ef the type used in automobile tail lights (fig. 1, G), 
This causes the beam of light to go on and off about 70 times a minute. The 
. frequency lowers to less than 60 times a minute as the battery becomes wea- 
ker. A continuous beam can readily be produced by shorting the "flsher" from 
the circuit. ; 
An ordinary alarm clock equipped to turn off the battery current about 
8 minutes out of each quarter hour is illustrated in figure 2. The copper 
plate is insulated from the clock by rubber, The beacon operates only when 
the current is turned on by the minute hand of the clock making contact with 
the inside projections of this copper plate. The original minute hand of the 
clock was replaced with a piece of spring brass and the hour hand removed, 
The case protecting the motor and other parts of the beacon is weather-= 
proofed with a single piece of galvanized. metal, which extends down about 1 
inch over each side. A small rim is soldered around the hole through which 
the beacon shaft revolves. A "skirt", which is fastened to the shaft, pro- 
jects downward over the soldered rim and prevents rain and snow from enter- 
ing the case (fig. 1, B), Thus equipped, the beacon operates successfully 
in both rain and snow, 
The battery will have to recharged every second day if the beacon is 
operated continuously each night. If the beacon is used during the evening 
and the morning "flight periods" only, the battery will function for a week 
on one charging. This would necessitate two additional trins into the field 
each night: one to turn the beacon off when the evening duck flight is over 
