34 



Dr. F. T. Trouton. An Experimental [Nov. 21, 



English Plate Glass and Marble. 

 Force 14. 



Mean of two experiments— Glass = 0-000020 ; Marble = 0'00146 



Mean circumference of cylinders \ f^ aS 1 S 1 ~~ H ? 



J (.Marble = 15*1 



English Plate Glass and Alabaster. 

 Force. Alabaster. 



28 285 

 7 255 

 7 285 



Alabaster mean = 0-00275 

 Glass less than errors of experiment. 

 Mean circumference of cylinders ^ 



Alabaster = 16"4 

 English Plate Glass and Plaster of Paris. 





Plaster 



Force. 



of Paris. 



28 



78 



28 



81 



7 



76 



7 



90 



Glass less than errors of experiment. Plaster of Paris = - 00815. 



Mean circumference of cylinders / ^ aSS „ _ . — J"^ 2' 

 J I Plaster of Pans = 16*7. 



French Plate and French Plate. 





Weight per turn 





per unit force. 



Force. 



t J > 



21 



133 176 



21 



166 166 



21 



95 143 



14 



185 192 



14 



143 135 



14 



107 100 



Mean = 0*000144. 



it cy 



cylinder = 16'5. 



Mean circumference of cylinders / ^ rs * < ^ n( J eT ' 1 



I becond cylinder = 



