Prof. L. T. More 07i Electrostriction. 



13 



When the spark-length was altered, a considerable time 

 necessarily elapsed between readings, as the difference between 

 consecutive values indicate. Before this series of experiments, 

 the image was perfectly stationary, and it was not until the 

 tube had been charged that a continuous increase in length 

 occurred. 



The up and down deflexions were always accompanied by 

 a slight horizontal motion. The deflexion begins slowly, 

 and increases rapidly during the latter part of the charging, 

 being especially rapid just before and at the time the spark 

 passes. After the spark, the mirror oscillates rapidly and 

 then comes to rest, nearly always at the final reading ; the 

 return is slow and never to the full amount of the original 

 deflexion. 



Table V. — Tube 5. Length of Armature, 50 cms. 



Spark- 

 length. 



Initial 

 Eeading. 



Final 

 Eeading. 



Deflexion. 



Eemarks. 



12 mm. ... 



190 div. 



145 



135 



175 div. 



125 



120 



15 div. 

 20 



15(v) 



1 jar in circuit. 



Time to charge \ minute. 



Discharged and left standing 7 minutes. 



12 mm.... 62 25 37 I Time to charge 1 minute. 

 18 233 35 i 



Discharged and left standing 1 minute. 



12 mm. ...1 213 

 173 

 163 



193 

 163 

 130 



20 Time to charge 1 minute. 



lO(') 



33 



Discharged but time not measured. 



12 mm.... 



1 



43 



25 



38 1 5 i 3 jars in circuit. 

 18 ' '' j '^^^® to charge less than 

 15 seconds. 



Table VI. — Tube 5. Length of Armature, 50 cms. 



Spark-length. 



Initial 

 Eeading. 



Final 

 Eeading. 



Deflexion. 



Eemarks. 



16 mm 



50 



193 ■ 

 123 



75 



35 

 167 



82 

 57 



15 

 26 

 41 



18 



Discharged 5 min. 

 Discharged 1 min. 

 Discharged 10 min. 



The tube was ruptured when the spark was increased to 2 cms. 



