194 



MEMOIRS NATIONAL ACADEMY OF SCIENCES. 



[Vol. XV. 



In the case of the mousetrap, by "in slot" is meant that the long arm of the spring is inserted in the slot of the 

 U-shaped band. By "Right way, " reference is made to the direction in which the U-shaped band snaps. A "weak 

 snap " is occasioned by having the spring or springs inverted. If one spring is more nearly correctly inserted than the 

 other, count best one; that is, give credit for the best spring, and for that only, except in the last case. 



Schedule of scores. 



B: 



C: 



D: 



E: 



Head inserted correctly 



Nut screwed on — 



Properly between cross bars of handle .... 



Otherwise 



Score (wrench) ( 



Complete chain of singly joined links . 



One correct joint between links 



Two correct joints 



Three correct j oints 



Four correct joints 



Score (chain) 



Thumb lever inserted in armholes — 

 Below spring, arm of lever out . . 

 Above spring wrong side forward . 

 Score (tube shut off) 



Thumb lever on pin either way 



Gear on pin right side up in mesh with lever . 



Knockers right side up in mesh with gear 



Cover screwed on 



Spring hooked 



Score (bell) 



F: 



Center stud in place. 



Springs in place 



Caps in place — 



Out of order 



In order 



Cover snapped — 



Two sides 



Three sides 



Workability 



Score (coin box)... 



Spring correctly placed on one stick. 

 Imperfect usable clothespin — 



Unsymmetrical 



Symmetrical 



Score (clothespin) 



( ) 



3 

 8 



( ) 



1 

 1 

 2 

 1 

 2 

 ( ) 



2 

 1 



1 

 3 



1 



2 

 2 



( ) 



G: 



Small lever in place 



Lock bolt in place 



Spring inserted — 



Workably 



Properly 



Top fitted on properly and screw inserted . 

 Score(lock) 



I: 



Both levers backward 



One forward clear in, other backward 



Other part way in, forward 



Both part way in, forward 



Both clear in, forward, one facing wrong. 



Both facing wrong 



Score ( paper clip) 



( 



Button properly inserted in upper ring 



Circuit-closing disk properly fitted in bottom 



ring 



Rings snapped together 



Score (electric button) ( 



U-shaped band held in proper place by pin or 



wire 



Trip lever or pin — 



Improperly 



Properly 



Wire lever hooked — 



Improperly 



Properly 



Springs on pin (count best one) — 



Weak snap, not in slot, either way 



Weak snap, in slot, either way 



Strong snap, in slot, wrong way 



Strong snap, in slot, right way, 



One spring 



Both springs 



Score (mouse trap) ( 



ABBREVIATED MECHANICAL TEST. 



The abbreviated mechanical test includes only items A, B, D, E, and G of the complete test. Time, 15 minutes. 

 Score each item according to directions given above and double their sum to secure the total score. 



Table of norms. 

 [Derived from 909 cases; 303d Engineers, Camp Dix.] 



Score. 

 0.. 

 10.. 

 20.. 

 30.. 

 40.. 

 50.. 

 60.. 

 70.. 

 80.. 

 90.. 

 98.. 



Precentile 



rank. 

 Per cent. 



.. 

 .. 1.5 

 .. 6 



.. 12 



.. 22 



.. 37 



.. 53 



.. 69 



.. 83 



.. 94 



.. 100 



Letter rating. Score. 



A 96-100 



B 80-95 



C 40-79 



D 20-39 



E 0-19 



