TRANSACTIONS OF THE SECTIONS. 



183 



from the cylinder, in consequence of the evaporation of the water absorbed, was in 

 these experiments noted, and it was found the specimens decreased in weight be- 

 low their original weight when dry. 



In the whole of these experiments the pressure was 20,000 per square inch, area 

 of specimens 8 square inches, and thickness about |-th of an inch. 



Table V. 



Summary of Results, showing approximately the time required iu the case of each 

 Cable for a loss of charge equivalent to a fall of the Electrometer Needle of 50°. 



o i> 



Description of core. 



1,2. 



3. 

 4,5. 



1, 2, 3. 



4. 



5,6. 



7. 



8,9. 



10. 



11, 12, 13. 



[ I. Gibraltar core cured J 

 by Mackintosh . . j 



II. Core impregnated 

 with insulating li-^ 

 quid [ 



0j M 





* 



10,000 

 10,000 

 10,000 







10,000 

 10,000 

 10,000 

 10,000 

 10,000 

 10,000 



1,2. 



2 

 3,4. 



1, 



2,3. 



5. 



6. 



1. 

 2. 



1 ° 

 3. 



4, 5, 6. 



7,8. 



1. 



9 



1. 

 2. 



3. 



III. Wray's core . 



IV. Wray's core 



f V. Core impregnated^ 

 J with insulating li- \- 

 quid J 



VI. Core of 20 alter- ] 

 nate coats of gutta ( 

 perch a and Chat- f 

 terton's compound , 



VII. Core of pure in- { 

 dia-rubber I 



Vffl. Gutta percha core 



[ IX. India-rubber core < 







10,000 

 10,000 







10,000 

 10,000 

 10,000 





 10,000 



c is 



111 



4-363 

 4-363 

 4-363 







4-363 



4-363 



4-363 

 4-363 

 4-363 

 4-363 







4-363 

 4-363 



3 2 



m O 



282 

 328 

 405 





 24 

 48 

 56 

 77 

 120 

 170 







4 

 10i 







4-363 

 4-363 

 4-363 





 4-363 







10,000 

 10,000 

 10,000 



X. Silver's india-rub 



■'{ 







3977 





 

 







4-363 

 4-363 

 4-363 





 1-72 





 121 



150 

 170 



.EJ o 



<* o 



H«2 



136 20 



100 



32 30 



6 20 

 11 40 

 27 35 

 13 

 62 

 97 

 105 



1300 



411 



68 30 

 44 15 





 80 





 264 

 480 

 576 





 390 



95 30 



42 45 



118 



100 50 



443 

 18 



Comparing the numbers in this Table with those in the first series, it becomes 

 evident that temperature has a considerable effect on the amount of water absorbed. 

 Thus gutta percha at 45° F. absorbed 0-044 grain, at 75°, 0-27 grain, or six times 



