no REPORT OF THE PSYCHOLOGY COMMITTEE 



duced In any desired quantity at relatively small expense, 

 and without demanding the services of expert machinists for 

 construction. The graphic record was added to show the 

 pointer and his Instructor the relative adequacy of the point- 

 ing at each moment. The movements of the target, the 

 sights, and the training mechanism were designed to dupli- 

 cate actual service conditions as closely as practicable in 

 simple construction. 



"Successive records of the same recruit furnish a record 

 of his progress in acquiring the coordinations necessary for 

 gun-pointing. Gross incapacity or natural aptitude will be 

 apparent In such a series. The instrument thus serves the 

 double purpose of a shore-training device and a test by which 

 marked natural inaptitude may be discovered with a minimum 

 loss of time. 



"Since the instrument is quite robust it is practicable for 

 interested recruits to practice gun-pointing with it at odd 

 times by themselves and without supervision. Experience 

 with the instrument shows that the recruits do take an inter- 

 est in It and use it practically continuously when permitted 

 to do so. 



"The base of the apparatus consists of a rectangular pipe frame- 

 work, four feet high, six feet long, and two and one half feet wide. 

 Each corner post carries an adjustable seat for the gun-pointer, 

 and a skeleton gun. The latter is really a peep sight built Into an 

 iron pipe. This may be trained by a two-handed belt gear. At 

 its muzzle end each skeleton gun carries a light but rigid recording 

 lever, armed on its distal end with a soft lead pencil for making the 

 records. 



"The targets for the four guns are carried on a platform that 

 moves across their line of action. The device for giving the tar- 

 gets an Irregular series of harmonic wave motions corresponding to 

 the movements of a floating gun-platform consists of a motor which 

 drives a set of three wooden pulleys. The first pulley serves merely 

 as a reducing gear. The second and third pulleys carry eccentric 

 attachments to pull the target platform a greater or shorter dis- 

 tance, at greater or less velocity, according as they work together 

 or in more or less complete opposition. The slack of the eccentrics 

 is taken up by a long spring, which is attached to the target plat- 



