G08 
On  Irrigation  in  Switzerland. 
formant,  M.  Jean  Herzog  of  Aarau,  told  me  that  the  water  they 
apply  possesses  the  most  fertilizing  qualities — that  it  is  of  a pecu- 
liarly soft  nature — and  that  he  has  at  times  observed  a kind  of 
soapy  or  oily  ( savoneuse ) substance  floating  over  the  meadows 
when  they  are  in  water.  When  the  streams  are  increased  by  the 
melting  of  the  winter  snows,  the  water  loses  its  efficacy,  but  when 
thickened  with  rain  their  efficacy  is  increased.  Also  when  the 
water  is  suffered  to  flow  over  too  large  an  extent  of  land  its  virtue  is 
invariably  diminished.  M.  Herzog  also  informed  me  that  he  never 
irrigated  during  the  full  moon,  as  he  had  always  observed  that  when 
the  meadows  were  allowed  to  remain  in  water  during  the  clear 
moonlight  nights  that  the  grass  was  perceptibly  weakened,  and 
that  its  very  colour  was  affected.  He  had  applied  water  to  dif- 
ferent parts  of  the  same  meadow  during  the  full  and  new  moon, 
and  had  experimentally  verified  this  fact. 
During  the  extreme  heat  of  the  summer  the  water  is  not  left  on 
the  meadows  by  day,  but  is  turned  on  during  the  night. 
The  water  is  supposed  to  act  as  a species  of  manure.  The  tests 
of  that  description  of  water  which  may  be  applied  with  advantage 
to  the  purposes  of  irrigation  are — 
1.  The  power  of  dissolving  soap. 
2.  The  good  quality  of  the  trout  that  inhabit  the  stream. 
3.  The  growth  of  the  water-cress  and  weed  at  the  bottom  of  the 
water. 
Spring  water  from  a source  warm  in  winter  and  cool  in  summer 
is  by  some  persons  considered  more  productive  than  the  water  of 
streams. 
Streams  that  leave  calcareous  deposits  on  their  banks,  or  that 
form  petrifactions,  are  always  injurious,  and  those  inhabited  by 
coarse  fish  alone  tire  generally  bad. 
M.  Herzog’s  method  of  treatment  of  his  water-meadows  is  as 
follows : — After  the  last  crop  of  grass  is  cut,  which  generally 
takes  place  in  the  beginning  of  October,  the  water-courses  are 
cleared  out,  the  hollows  are  thus  filled  up,  and  the  meadows  are 
irrigated  during  the  months  of  October,  November,  and  December, 
till  the  hard  frosts  commence  and  the  winter  snows  fall.  Should 
there  be  snow  and  the  weather  not  very  severe,  the  water  is  still 
kept  flowing  over  the  meadows  in  order  to  melt  the  snow  ; but  as 
soon  as  there  is  any  fear  of  the  water  freezing  irrigation  is  discon- 
tinued. 
The  water  is  made  to  flow  over  the  land  for  two  or  three  days. 
It  is  then  turned  off  and  employed  in  irrigation  elsewhere;  and 
after  the  interval  of  a week  or  a fortnight,  according  to  the  ap- 
pearance of  the  grass,  it  is  again  made  to  flow  over  the  same  land 
for  a similar  period.  This  system  is  continued  till  the  irrigation 
is  stopped  by  the  frost  and  snow,  and  the  irrigation  during  the 
