154 THE GYROSCOPE FOR MARINE PURPOSES. 



by means of which the whole gyroscope proposition is reduced to a strictly 

 mechanical basis easily within the comprehension of all and containing no 

 unknown quantities and correspondingly easily dealt with. In the cases 

 where the gyroscope is employed as a battle compass, the apparatus is 

 placed below decks, and small instruments about the size of an ordinary 

 compass are distributed in different positions on the ship, giving the exact 

 indications of the gyroscopic compass itself. 



My work has extended to the point where action of such instruments 

 can be controlled from the gyroscopic compass and distributed as desired, 

 the indications being accurate to a very small fraction of a single degree. 

 Many observations have been made indicating that they are accurate 

 to thirty-six hundredths of an entire circle. Plate 59 shows a view of 

 the battle compass as it is mounted on an artificial ship which gives all 

 changes of heading, as well as automatic continuous roll and pitch to which 

 the compass is continually subjected. Both roll and pitch may be varied 

 at will as to angle and period. 



Plate 60 shows one of the receiving instruments for the binnacle or 

 other position. It is found that this receiving instrument requires no 

 cardian mounting and is equally accurate in any position, vertical or hori- 

 zontal. Indications are held with the accuracy described following the 

 master instrument instantly, and are very much more "dead beat" than 

 an air compass for marine purposes, though they are not submerged nor 

 is any liquid used in connection with them. Among the points never before 

 realized is the automatic correction of the northerly or southerly component 

 of vessels' speed at sea, this correction being made between the gyroscopic 

 compass and its transmitting member, in such a manner that the indica- 

 tions received by the navigator and elsewhere about the ship are thus 

 absolute and maintain true geographical north. 



A settling curve taken from my gyroscopic compass while in the opera- 

 tion of being started in the east and west position and brought up to about 

 4,000 revolutions per minute only shows the instrument to reach true north 

 in 34 minutes; at normal speed the directive force is about 6,600 times 

 that of the compass needle. 



It is felt that the navigator has now at hand a most desirable aid and 

 one that greatly simplifies his work. 



It will be understood that this type of compass is not affected in the 

 slightest degree by the steel of the ship, or cargo, nor any magnetic dis- 

 turbances in either; neither should shifting cargo, turning turrets, gun-fire, 

 nor the striking of a ship by a shot disturb its accuracy or reliability, nor 

 is it aft'ected in the slightest by those disturbances technically known as 

 deviation or variation. 



