612 
Report  on  Implements  at  York. 
They  are  thus  allowed  to  “ wobble  ” on  the  shaft,  which  causes 
the  wires  of  the  screen  always  to  be  closer  together  at  the 
bottom  than  at  the  top.  The  appearance  of  the  screen,  and 
the  peculiar  arrangement  of  the  upper  and  under  surface,  will 
be  understood  by  the  drawing  on  p.  611. 
The  difference  of  length  above  and  below  is  about  four  or  five 
inches.  A trial  was  made  with  a mixture  of  grain  and  weed- 
seeds,  which  was  quite  satisfactory  as  to  efficiency.  The  price 
of  screen  and  frame  for  hand-power  is  15 1. 
Priestman  Brothers’  Dredrjer  (No.  5962). — Messrs.  Priestman 
Brothers,  of  Hull,  have  exhibited  their  well-known  Dredging, 
Excavating,  and  Elevating  Machines  in  the  Showyard  of  the 
Royal  Agricultural  Society  for  many  years,  but  this  is  the  first 
occasion  on  which  they  have  shown  a machine  which,  both  on 
account  of  its  capacity  and  price,  could  be  properly  regarded  as 
Fig.  12. — Side  view  of  Priestman’ s Dredger. 
adapted  to  agricultural  work  : the  larger  machines  hitherto 
shown  being  suitable  for  contractors’  works,  and  not  for  private 
enterprise.  The  cleansing  and  deepening  of  narrow  water-ways, 
drains,  dykes,  and  small  streams,  is  work  of  such  vital  import- 
ance in  flat  outfall  districts,  that  the  value  of  any  invention 
which  expedites  and  cheapens  such  operations  cannot  easily  be 
