-±40  Mr.  E.  F.  Burton  on  the  Properties  of 
Table  III. — Silver  Solutions. 
No. 
Voltage. 
Current. 
Time  of          Velocity  in  cm./sec.    ' 
Sparking.           per  volt  per  cm. 
1 
2 
o 
u 
SO  volts. 
60     „ 
40     „ 
8 "5  amperes. 
7'5        „ 
6-5 
10  minutes.               19-7xl0~5 
20        „                     19-6  Xl0~5 
30       „                   19  3xl0-5 
Since  there  is  no  a  priori  reason  for  assuming  that  all  the 
particles  are  of  a  uniform  size,  these  results  would  confirm 
Lamb's  theory. 
We  are  here  dealing  with  the  motion  of  small  charged 
particles  through  a  liquid,  so  that,  other  things  being  equal, 
the  velocities  of  those  particles  should  depend  upon  the 
viscosity  of  the  liquid,  and  therefore  to  a  large  extent  upon 
the  temperature  of  the  liquid.  A  neglect  of  this  influence 
soon  leads  to  bewildering  results.  That  the  dependence  on 
the  temperature  is  quite  direct  is  shown  by  placing  side  by 
side  the  results  given  in  Table  I.,  and  the  velocity  found  for 
the  same  solution  at  a  different  temperature  (Table  IV.).- 
Table  IV. 
Metal. 
Temp. 
Coefficient  of      \     v  ,     ■>„ 
Viscosity  of  Water.      Vel°f?- 
U0 
Vfx  X  10~5. 
Silver j 
11°  C. 
21°  C. 
•012822             19-6  Xl0~5 
•009922          I  25-2xl0~5 
1 
•251 
•250 
VII.  Remarks  on  Velocities  in  Table  II. 
It  will  be  noticed  that  while  the  velocities  recorded  above 
are  distinctly  lower  than  those  given  by  Whitney  and  Blake, 
they  are  in  close  agreement  with  those  found  by  Hardy  *  for 
solutions  of  a  similar  nature.  Although  they  are  of  the  same 
order  as  the  velocity  of  the  metallic  ions,  still  the  slowest 
moving  ion  travels  more  quickly  than  the  fastest  colloidal 
particle. 
In  considering  the  results  given  in  Table  II.,  one  is  struck 
with  the  fact  that  the  particles  of  the  more  electro-positive, 
oxidizable  metals  are  all  positively  charged,  while  the  more 
*  Journ.  of  Physiol,  vol.  xxxiii.  (Dec.  1905)  p.  291. 
