Determining the Elastic Constants of Glass. 



56a 



Table IV. 



Glass 3 b. 



Width of beam = 3*25 cm. Thickness = -409 cm. 

 Bending rnoment = 207kg. cm. 



This glass exhibits initially similar characteristics in the cross- 

 bending to those observed in Glass 1 a. The mean curvature is 

 shown in column 1 to be greater at the centre than at the edges, 

 while column 2 indicates a region of minimum curvature near 

 fringes 9 to 12, and an increase toward the edge. 



After 50 minutes the curvature on the whole has increased and 

 become much more uniform. 



The longitudinal curvature again shows an increase. 



Table IV.— Glass 3 b. 



Transverse Fringes. 



N. 



After 1 Minute. 



After 50 Minutes. 





$(A n+8 a -A n *). 



MA n+2 2 -K 2 )- 



l(A?i + 8 2— A„ 2 ). 



1/ A " 



-A, 2 ). 



1 



2 



•406 



•407 



..A 



^•404 



•404 



•105 



y-40i 





3 



•411 





-407 





4 



•413 

 •412 

 •413 





407 

 •407 

 •406 







5 

 6 



^408 



•'V 



" [-403 





7 



•413 



•407 





8 



•412 





•405 







9-12 



Mean Value 



... -425 



Mean Value 



... -411 





13-16 



■411 



... -410 



■406 



... -400 





Lc 



ngitudinal Fringes. 





-A w 2). 





N. 

 1 



&A n+i *-A n *). 



*(^«+4" 



•093 



•090 





2 



•089 



•091 





3 



•091 



■089 





4 



•089 



•089 







Mean Value 



Mean Value 







•OS 



>05 



■08 



97 





