of the Descent of Glaciers by their Weight only. 147 

 Deflection of a Rod of Ice. 









Modulus of elasticity 



Index- 

 number of 

 experiment. 



Load, in ounces. 



Deflection, in 

 inches. 



on the supposition 

 that the elasticity of 

 the rod remained per- 

 fect throughout its 

 deflection. 



]. 







•04 



4956300 



2. 



4 



•06 



5109200 



3. 



8 



•08 



5185800 



4. 



12 



•10 



5231600 



5. 



16 



•12 



5262300 



0. 



20 



•14 



5284400 



7. 



24 



♦16 



5301000 



8. 



28 



•18 



5313600 



9. 



32 



•20 



5323700 



10. 



36 



•22 



5332000 



11. 



40 



•24 





12. 



44 



-26 





13. 



48 



•28 





The weights were here taken off 

 the rod was found to be "10 inch. 



, and the perman 



ent deflection or set of 



14. 



54 



•30 





15. 



58 



•32 





16. 



62 



•34 





17. 



64 



•36 





Permanent set *12 inch. 







18. 



G6 



-M 





19. 



70 



•38 





20. 



74 



•40 





21. 



78 



•41 





22. 



82 



•44 





2,3. 



86 



•46 





24. 



90 



•48 





25. 



94 



•50 





Permanent se 



t -IS inch. 









The rod finally broke with a load of 7 lbs. As eacli addi- 

 tional load was placed on it, it vibrated, showing its elasticity 

 (within the narrow limits of vibration) to remain nearly perfect. 

 Each additional weight gave it, however, eventually an additional 

 set. The following seem, from these and other experiments, to 

 be physical properties characteristic of ice : — ■ 



1. The preservation of the continuity of its substance when 

 it is made to shear. I will venture to call this readhesion. 



2. Its extreme brittleness. 



3. Its elasticity at low temperatures. 



4. Its tendency when deflected easily to take a set. 



I have calculated the modulus of the ice-rod as shown in the 

 first ten of the experiments, of which the results are given in 

 the preceding Table, on the supposition that the elasticity of the 



L2 



