THE COMMERCIAL GYROSCOPIC COMPASS. 213 
behavior on the first few voyages. All such maneuvers could be easily avoided 
by employing the new compass, which is totally unaffected by any magnetic con- 
ditions whatever, and which at the same time may be used to adjust all magnetic 
compasses as often as desired. 
Three standard compass equipments are supplied, the simplest of which is 
shown in Fig. 1, Plate 123, and the most complete in Fig. 2, Plate 123. As will be 
seen, the simpler equipment consists only of the master compass, motor generator, 
and a very simple switch panel, while the larger equipment contains in addition a 
pelorus stand, storage battery, two repeater compasses, and a larger switchboard, 
one panel of which is to care for the repeater compasses. These equipments are 
being installed on the secondary naval ships and the larger ships of the merchant 
marine. 
Another equipment is also provided in which the pelorus stand is omitted 
and a switchboard intermediate between the two illustrated is supplied. The 
entire master compass operates on alternating current, and in the case of the 
equipment where no repeater compasses are used, the motor generator simply 
converts a slight amount of the ship’s supply of direct current into alternating 
current of the proper voltage and frequency. The generator operates auto- 
matically. The repeater compasses, however, operate on a low voltage direct 
current, and the motor generators for these equipments are extended on one end 
and serve also to generate the slight amount of low voltage direct current required. 
In these equipments a storage battery is also provided, and arrangements are 
made so that, in case of failure of the ship’s supply, the entire compass equipment 
will be automatically transferred to the storage battery, which has sufficient capacity 
to carry the entire equipment independently for a period of two or three hours. 
The binnacle of the master compass is provided with lock and key to prevent 
meddling by unauthorized persons. In order to make the frequent removal of 
cover or bowl unnecessary, and to make it possible to inspect the compass through 
the glass cover, a lamp is provided in the pedestal for the illumination of the 
inside of the binnacle. { 
Figure 3, Plate 124, gives a sectional view of the binnacle and portion of the 
compass showing the internal arrangement and heavy glass cover. 
Figure 4, Plate 124, gives a view of the navy type of gyro-compass card show- 
ing binnacle. 
Either of the two types of repeater compasses shown in Figs. 7 and 8, Plates 
125 and 126, may be used, each being supplied with several types of mounting. As 
far as the repeaters themselves are concerned, the principal difference in the two 
types is in the size of the card, the mechanism which drives the card being the same. 
In either type the part of the card that carries the degree marks is made of trans- 
lucent material and is illuminated by means of a lamp contained within the re- 
peater casing, which may be turned on or off, or, what is most important for the 
helmsman, may be dimmed to any degree by means of a dimmer, which is weather- 
proof and forms a part of the equipment. 
