ME.  HOENEE  ON  THE  ALLUVIAL  LAND  OE  EGYPT. 
81 
quantity  of  water  coming  from  Abyssinia  is  different  now  from  what  it  was  then.  An 
inscription  in  Greek  characters  traced  in  the  wall  of  the  Nilometer  has  the  date  of  the 
reign  of  Septimius  Severus,  and  the  object  of  it  seems  to  have  been  to  mark  an  inunda- 
tion that  had  risen  several  palms  above  the  twenty-fourth  cubit.  It  is  probable  that  the 
inundation  referred  to  was  not  an  extraordinary  one,  but  that  the  Romans  who  formed 
the  garrison  at  Syene  in  that  reign,  ignorant  of  the  effect  of  the  natural  rise  of  the  bed 
of  the  river,  noted  it  as  a remarkable  event,  supposing  that  the  highest  point  of  the 
twenty-fourth  cubit  was  a fixed  point,  beyond  which  the  annual  flood  of  the  river  could 
never  rise.  Now  admitting  the  highest  inundations  to  have  reached  the  mark  traced 
above  the  twenty-fourth  cubit,  that  is  to  say,  that  they  had  risen  above  it  about  0‘31  metre 
(12‘205  inches)  at  the  date  of  the  inscription,  it  will  be  easy  for  us  to  fix  the  amount  by 
which  the  bed  of  the  Nile  at  Elephantina  has  been  raised  between  that  epoch  and  the 
present  day.  Thus,  Septimius  Severus  became  Emperor  in  a.d.  193,  and  died  in  211, 
and  supposing  the  inscription  to  have  been  cut  on  the  stone  in  the  middle  of  his  reign, 
the  bed  of  the  Nile  will  have  risen  2T1  metres  (6  feet  11  inches)  in  1600  years,  which 
gives  0T32  metre  (5T92  inches  in  a century).” 
M.  Girard  then  gives  the  observations  he  made,  with  the  same  object,  at  the  Nilo- 
meter on  the  island  of  Rhoda  near  Cairo,  which  he  states  to  have  been  reconstructed 
about  A.D.  847.  “There  can  be  no  doubt,”  he  says*,  “that  at  the  time  when  this 
Nilometer  was  erected,  its  16th  cubit  by  which  it  is  terminated  indicated  a year  of 
plenty,  for  it  has  always  been  of  importance  for  the  government  to  know  the  extent  of 
the  rise  of  the  inundations,  by  which  they  could  levy  the  largest  amount  of  duty.  If 
therefore  the  inundation  had  risen  higher  than  the  existing  Nilometer,  it  is  evident  that 
they  must  have  added  to  the  height  of  the  column,  in  order  that  it  might  show  the 
inundations  the  mo^t  favourable  to  the  exchequer.  Now,  in  the  present  day,  if  the  Nile 
does  not  rise  above  the  16th  cubit  of  the  Mekyas  (Nilometer),  it  is  considered  unfavour- 
able. That  of  1799,  for  example,  was  considered  to  be  one  of  the  least  favourable,  and 
yet  it  rose  to  16  cubits  2 digits.  But  the  following  year  was  one  of  plenty,  and  the 
water  had  risen  to  18  cubits  and  3 digits,  thus  making  a difference  of  2 cubits  and 
3 digits  between  the  highest  rise  at  the  time  of  the  erection  of  the  Nilometer,  and  that 
to  which  it  had  risen  in  1800,  or  1T49  metre  (45‘237  inches)  in  953  years,  which  is 
equal  to  0T20  metre  (4‘742  inches)  in  a century.”  The  difference  between  0T32  at  Ele- 
phantina and  0T20  at  Rhoda  may,  he  considers,  be  accounted  for  by  possible  changes  in 
that  distance,  in  the  inclination  of  the  bed,  the  amount  and  velocity  of  the  stream,  and 
its  wearing  power  on  the  banks ; but  that  it  is  so  slight,  that  the  secular  rise  of  the  bed 
of  the  river  may  be  very  nearly  represented  by  the  mean  of  the  above  sums,  that  is  0T26 
metre,  or  4-960  inches. 
He  then  comes  to  a conclusion  which  I shall  give  in  his  own  words : — “ Quant  a 
I’exhaussement  moyen  du  sol  de  la  vallee  d’Egypte,  il  suffit  d’une  legere  attention  pour 
reconnaitre,  qu’il  doit  etre  exactement  le  memo  que  I’exhaussement  moyen  du  lit  du  Nil.” 
* Loc.  cit.  p.  264. 
