an Electric Micrometer. 



551 



in the streets, the disturbance being visible before any sound 

 of the cart could be heard. 



In every such case a delay was required. 



The value determined for one disk unit is given at the 

 bottom of Table IV. 



Table IV. 



Calibration results for the apparatus, using the levers with the 



lowest (usual) ratio. 



Numbers are expressed in a unit which is one hundred times 



the unit of the apparatus 10 ~ 7 cm.. 



King 



No. of 



Read- 



Diff. 



Mean. 



Ring 



No. of 



Read- 



Diff. 



Mean. 



Creep. 



Rings. 



ings. 







Creep. 



Rings. 



ings. 







1 ring in 



5 



61 



11-7 





1 ring in 



10 



231 



27-2 





60s 





44-4 



144 





30s 





459 



269 



277 



contract. 





30 



161 





contract. 





19 



26-6 







139 



131 



139 







424 



30-2 



or 







08 



12-9 



or 







12-2 



25-2 



for 1 ring 







379 

 22-9 



15-0 

 150 



for 1 ring 







37-0 

 6-6 



30-4 

 263 



2-77 







7-9 



129 



2-78 







303 



29-1 









45-2 



142 









1-2 



27-5 









31-0 











23-7 







1 ring in 



5 



26 8 



15-1 







10 



44-2 



27-4 





40s 





11-7 



11-9 









16-8 



26-5 





contract. 





49-8 

 37-3 



125 



14-8 



13-74 







403 

 125 



27-8 

 27-6 



27-5 

 or 







22-5 



150 



or 







349 



289 



for 1 ring 







7-5 



11-9 



for 1 ring 







5-0 



26-3 







456 

 321 



135 

 15 



2-75 







297 

 1-9 



27-8 

 271 



275 







171 



14 









24-8 



27-9 









31 











46-9 







Mean of 5 rings= 13-82. Mean of 10 rings=27'60. 



Mean (of 270) for 1 ring=2-76. 

 Or, allowing for creep =2'84. 



.-. * =284 units. 

 2 



589 



1 unit= ^284 W= 1-037 W- 



