New  Improved  Tiipe  of  Chronograph. 
399 
in  our  chronograph  attained  in  the  manner  described  above 
is  best  seen  from  the  fact  that  not  the  least  sound  (except 
from  the  fly)  can  be  heard  when  the  instrument  is  working, 
while  in  instruments  of  the  older  type  of  a  similar  speed 
harsh  sounds  both  in  the  clock  and  in  other  parts  of  the 
instrument  are  heard,  indicative  of  the  irregularity  of 
motion. 
In  figure  II.  (&  PL  VIII.  fig.  2)  the  vertical  type  of  our 
chronograph  is  given.     The   principles   and  details  are   the 
same  here  as  in  the  horizontal  type  and  are  indicated  by 
the  same  letters.  Here  the  spindle  is  arranged  with  its 
driving  end  upwards,  the  weight  of  the  pen-carrying  system 
being  taken  by  the  half  nut  (8)  on  the  drum. 
A  detail  of  this  portion  is  given  in  figure   III.,  a  hinged 
