438 Mr. Scrymgeour's Experiments to determine the Influence 

 Set, No. 10. — With an oval leaden bob of 8 pounds weight. 



i?™„,.; m or.* Gain in Extent of 



Experiment*. 24 Hours. Vibration. 



In air -f 10'6 S 2*7° 



Ditto +10*1 2-7 



In exhaustion, 6 in. . . +9*1 3*15 



Ditto 13J . . +9-5 29 



In air + 9'0 2*7 



Ditto +9-5 



Set. No. 11. — With the pallets set so as to give the impulse 



all, or very nearly all, in the ascent. 



t^ . Gain in Extent of 



Experiments. 2 4 Hours. Vibration. 



In air + 6'6 S 2-63° 



Ditto +6*2 2-63 



Ditto +6-4 2-63 



Set, No. 12. — With the pallets set so as to give three fourths 

 of the impulse in descent. 



r, . . Gain in Extent of 



Experiments. 24 Hours. Vibration. 



In air + 7'3 S 2*8° 



Ditto +7*6 2-8 



For the experiments in Nos. 1 1 and 12, it was necessary that 

 the pallets should be of a peculiar shape. It was formerly 

 stated that they were ground hollow in the flanches for the 

 purpose of giving the impulse in descent. The pallets were 

 sufficiently broad to admit of two separate actions of the wheel; 

 one half of the thickness of each, on the same side, was ground 

 flat in the way usually done for a dead scapement. It was also 

 stated that the pallets were jointed concentrically on the axis. 

 The central brass collet or socket on which they were jointed, 

 was fixed to the arbor by a pinching screw. By this means, 

 the pallets could be moved along the arbor, and thus the ac- 

 tion of the wheel could be shifted from the one to the other 

 at pleasure, and the wheel could also be put out of action al- 

 together, if required. In order to give the whole impulse in 

 ascent, the pallets required to be pitched deeper in the wheel 

 than usual ; and in order to clear the teeth properly, they re- 

 quired to be made thinner or shorter in the flanches; this 

 caused a corresponding loss of power. 



The portion of the pallets which was employed to give the 

 impulse in descent, was a little deeper or thicker than the 

 portion used to give the impulse in ascent. By this means, a 

 greater impulse was given in the former case than in the latter ; 

 and thus the greater extent of vibration in the experiments of 



