1895.] 



Investigation of the Laws of Attrition. 



33 



Quartz and Plaster of Paris. 



Force. Plaster of Paris. 

 28 70 

 14 71 

 7 71 

 4 75 



Quartz less than errors of experiment. Alabaster = O0072 



Mean circumference of cylinders \ Q uartz — 



( Plaster of Paris = 16" 7 



English Plate and English Plate. 



Weight per turn 

 per unit force. 



Force. 







35 



137 



134 



35 



80 



74 



28 



82 



91 



28 



89 



84 



21 



95 



85 



21 



123 



104 



21 



95 



100 



Mean = 0'000097 



Mean circumference of cylinders { ^ rs ^ , ~~ ^ ? 



J [Second = 17*3 



English Plate and French Plate. 

 Force. English plate. French plate. 



21 



90 



171 



14 



93 



115 



14 



92 



142 



14 



97 



162 



14 



92 



142 



English plate glass = 0-000093. French plate glass = 0'000146 



Mean circumference of cylinders •[ ^ n §^h P^e 17 2 

 J I French plate = 16-9 



English Plate Glass and Serpentine. 

 Force. Serpentine. 

 28 47 

 14 38 

 14 45 

 14 45 

 4 48 



Glass (mean over all) = 0'000003. Serpentine = 0*00044 



Mean circumference of cylinders \ ^ ass ~~ ^ ? 



C berpentme = 17*5 



VOL. LIX. r> 



