August  i,  1892.I  THE  TROPICAL  AGRICULTURIST.  131 
the  quilt  from  his  body  at  pleasure  ; but  the  mode 
most  frequently  adopted  was  to  have  this  bamboo 
cylinder  under  the  bed-clothes  to  keep  the  quilt  off 
the  sleepers.  It  was  about  the  size  of  a human 
being  and  each  person  took  this  to  bed  with  him. 
The  Chairman,  in  closing  the  discussion,  said 
that  he  thought  some  attention  might  be  advan- 
tageously given  in  Europe  to  the  use  of  bamboo  for 
musical  instruments,  more  particularly  the  organ. 
Mr.  E.  Satow  proposed  a vote  of  tliaks  to  the 
lecturer,  which  was  seconded  by  Mr.  F.  T.  Edwards, 
and  carried  unanimously. 
Mr.  Holme,  in  acknowledging  the  compliment 
said,  with  regard  to  the  spear  in  Japan,  it  was  made 
of  a class  of  bamboo  that  was  solid  throughout.  It 
was  common  enough  in  India,  but  it  was  very  rare  in 
Japan,  and  only  occurred  in  a small  district.  That 
was  why  he  had  made  no  reference  to  the  use  of 
bamboo  as  a weapon.  -London  and  China  Express. 
SAND -WASHING  APPARATUS. 
One  of  the  most  important,  and,  at  the  same  time’ 
most  difficult  and  expensive,  operations  in  connexion 
with  waterworks  practice  is  that  of  cleansing  the 
sand  used  for  filtering  purposes.  The  sand  must  be 
removed  from  the  filter  beds,  some  of  which  have 
an  area  of  several  acres,  and  thoroughly  cleansed 
from  its  accumulation  of  impurities  before  it  can 
be  replaced  for  use,  and  this  is  a tedious  operation 
involving  a large  amount  of  manual  labour.  There 
are  various  ways  of  carrying  out  this  operation, 
but  they  are  all  open  to  the  objections  stated. 
Numerous  schemes  have  been  tried  for  improving 
and  cheapening  the  ordinary  process,  but  they  have 
hitherto  proved  only  partially  successful.  An  impor- 
tant advance,  however,  has  been  made  by  Messrs, 
Hunter,  Fraser,  and  Goodman,  who,  being  practical 
engineers,  have  worked  out  a system  in  which  the 
difficulties  of  sand-washing  are  entirely  overcome. 
This  system  has  been  put  in  operation  at  the 
Kew-bridge  Works  of  the  Grand  Junction  Water- 
works Company,  of  which  Mr.  Frazer  is  the  en- 
gineer. The  method  of  washing  sand  hitherto  adopted 
at  those  works  has  been  to  remove  it  from  the  filter 
bed  and  throw  it  into  washing-boxes  having  per- 
forated bottoms,  where  it  was  cleansed  by  an  ascend- 
ing current  of  water  under  pressure.  This  process 
was  at  once  wasteful,  slow,  and  costly.  The  new 
apparatus  consists  of  a receiver  which  is  placed  at 
the  level  of  the  filter  bed  and  into  which  the  sand 
is  tipped  by  the  barrowful.  From  this  receiver  the 
sand,  mixed  with  water,  is  carried  up  a tube  to  the 
first  of  a series  of  hoppers  on  the  bank  of  the  filter 
bed  by  means  of  an  injector  supplied  with  water 
under  pressure,  the  injector  opening  into  the  ascen- 
sional tube.  The  hoppers  are  of  cast  iron  and  are 
placed  about  7ft.  apart.  Each  hopper  is  2ft.  4in. 
square,  and  2ft.  2in.  high  over  all,  and  is  provided 
with  a jet  pipe  connected  with  a main  carrying  water- 
under  pressure  and  regulated  by  a valve.  These  hop- 
pers vary  in  number,  according  to  requirements, 
the  general  number  being  eight,  but  they  need  not 
all  be  used  at  the  same  time.  When  in  operation 
the  water  is  turned  on  and  issues  through  each  jet 
forcing  water  up  the  delivery  pipes  into  the  hopper, 
the  valves  being  so  regulated  as  to  give  an  uniform 
overflow  at  each  hopper.  The  dirty  sand  is  delivered 
into  the  first  hopper  of  the  series,  and,  gravitating 
to  the  bottom,  is  carried  forward  in  a mixed  stream 
of  water  and  sand  into  the  next  hopper.  This  pro- 
cess is  repeated  in  each  hopper  until  the  last  in 
the  series  is  reached,  which  discharges  the  clean 
sand  into  a truck  on  the  filter  bed  for  relaying  or 
at  any  other  point  where  it  is  wished  to  deliver 
it.  The  dirt  is  thoroughly  separated  from  the  sand 
and  passes  away  from  the  hopper  with  the  overflow 
water.  If  screening  is  necessary,  it  is  effected  by 
discharging  the  sand  and  water  from  the  first  hopper 
upon  an  inclined  screen  of  the  required  mesh,  and 
which  is  fixed  over  the  second  hopper.  With  a 
moderate  consumption  of  water  two  men  can  wash 
find  screen  three  cubic  yards  of  sand  per  hour,  no 
matter  how  dirty  the  sand  is.  There  are  two  sets 
of  this  apparatus  at  the  Hew  works,  where  they 
have  been  in  satisfactory  use  for  the  last  six  months. 
One  set  is  at  present  in  operation  cleaning  the 
whole  of  the  sand  of  a filter  bed  nearly  two  acres 
in  area,  while  another  set  is  at  work  cleaning  the 
surface  sand  of  another  filter  bed  three-quarters  of 
an  acre  in  extent.  These  operations  were  witnessed 
on  Friday  afternoon  by  a party  of  engineers  and 
other  gentlemen  interested  in  waterworks  practice, 
and  after  careful  inspection  it  was  the  opinion  of  those 
present  that  the  claims  of  efficiency  and  economy  made 
for  the  system  were  fully  established.  Mr.  Fraser  stated 
that  under  the  old  system  the  thorough  cleansing  of  the 
sand  of  the  larger  filter  had  cost  about  £2,000,  whilst,  by 
the  new  system,  it  was  more  quickly  effected  for  about 
£1,000. — London  Times , June  6. 
— . 
ECHOES  OF  SCIENCE. 
The  Sargasso  Sea  or  floating  masses  of  gulf  weed 
in  mid- Atlantic  which  impeded  the  ships  of  Columbus 
four  hundred  years  ago,  has  been  the  subject  of  careful 
study  by  Dr.  KrUmmel,  a German  mareographer,  who 
takes  a different  view  of  its  origin  from  that  com- 
mon y accepted.  He  shows,  to  begin  with,  that  the 
Sea  is  much  more  extensive  than  Humboldt  supposed. 
The  middle  or  thickest  part  is  elliptical  in  form,  the 
great  axis  lying  along  the  tropic  of  Cancer  and  the 
foci  at  45deg.  and  70deg.  west  longitude.  Around  this 
are  other  more  extensive  but  thinner  accumulations 
of  the  weed,  which  vary  with  the  prevailing  winds. 
The  gulf  weed  (fucus  natans ),  which,  with  its  little 
round  “ berries  ” is  not  unlike  the  mistletoe  in  form, 
but  of  a brownish-yellow  co  our,  has  been  thought  to 
have  lost  its  property  of  rooting  on  rocks,  and  to  have 
acquired  the  power  of  living  afloat.  It  has  even  been 
suggested  that  the  sea  marks  the  site  of  a submerged 
continent,  apparently  the  lost  Atlantis.  Dr.  Kriimmel 
holds  that  the  weed  has  simply  been  drifted  to  its 
present  position  by  the  Gulf  Stream  and  its  affluents 
from  the  West  Indian  Islands  and  the  Gulf  of  Mexico 
It  is  now  proved  that  the  Gulf  Stream  is  not  a single 
narrow  “river  of  the  ocean,''  as  Maury  poetically 
described  it ; but  consists  of  a number  of  currents,  not 
only  from  the  Mexican  Gulf,  but  the  Antilles.  The 
weed,  according  to  Dr.  Kriimmel,  would  take  fifteen 
days  to  float  as  far  north  as  the  latitude  of  Cape 
Hatteras,  and  five-and-a-half  months  to  reach  the 
Azores.  In  the  Sargasso  Sea  it  becomes  heavy  and 
sinks;  but  the  supply  is  kept  up  by  the  Gulf  Stream. 
Dr.  Kriimmel  is  certainly  right  in  giving  the  Sargasso 
Sea  a much  wider  area  than  Humboldt  did  and  than 
our  maps  usually  portray.  It  has  been  encountered 
some  two  oi  three  hundred  miles  north-east  of  Barba- 
does  ; but  whether  the  weed  is  solely  carried  from  the 
West  Indies  and  the  Gulf  is  perhaps  open  to  doubt. 
The  latest  results  of  meteoro'ogical  science  concerning 
the  general  circulation  of  the  atmosphere  are  thus 
summarised  by  Dr.  J.  M.  Pertner  in  a lecture  to  the 
Scientific  Club  of  Berlin.  In  consequence  of  the 
unequal  heating  of  the  globe  at  the  poles  and  the  equator 
winds  or  air  currents  are  set  up.  These  are  easterly 
in  the  zone  between  35deg.  north  and  35deg.  south 
latitude  ; and  westerly  outside  of  it.  In  the  northern 
hemisphere  the  easterly  currents  at  the  earth’s  surface 
become  more  northerly,  and  in  the  higher  strata  of 
the  atmosphere  more  southerly,  in  approaching  the 
latitude  35deg.  At  the  equator  there  is  a zone  of 
calms  near  the  surface  with  ascending  currents,  and 
a strong  east  wind  higher  up.  Again,  at  latitudes 
35deg.  north  and  south  there  are  surface  calms,  but 
with  descending  currents  and  a wind  towards  the  poles 
high  up.  North  and  south  of  these  belts  westerly 
winds  prevail  at  the  surface,  and  north-westerly  or 
south-westerly  trades  higher  up;  a'l  becoming  more 
westerly  with  increasing  latitude. — Globe. 
FRUIT  AS  FOOD. 
Now,  I will  tell  you  what  I claim  for  fruit  as  food; 
that  is,  for  fruit  as  a complement  of  one's  daily  diet. 
1 — That  it  is  exceeding  y palatable.  2 — That  it  causes, 
owing  to  this  very  palatableness,  an  increased  flow  of 
saliva.  3 — That  it  thus  assists  us  in  digesting  other 
