348 
On  the  Power  of  Soils  to  absorb  Manure. 
that  the  results  would  be  made  much  more  accurate  if  the  un- 
avoidable errors  of  experiment  were  distributed  over  a larger 
quantity  of  the  soil.  Thus,  for  instance,  in  the  last  experiments 
an  error  of  T7rroth  in  the  determination  of  the  ammonia,  is  mag- 
nified ten  times,  or  becomes  an  error  of  on  the  per-centage 
absorption  of  the  soil.  Those  who  are  acquainted  with  chemical 
operations  will  understand  how  difficult  it  is  in  such  a case  as  the 
distillation  of  ammonia  to  guard  against  so  small  a deviation,  and 
will  appreciate  the  accuracy  with  which  it  was  necessary  to 
conduct  the  experiments  if  results  of  any  value  were  to  be 
obtained.  To  diminish  as  far  as  possible  the  sources  of  error,  it 
seemed  advisable  to  increase  the  quantity  of  soil  in  relation  to 
the  liquid,  and  the  following  experiments  were  made  principally 
with  this  view  : — 
Experiment  71. — Pipe-clay  and  muriate  of  ammonia  : — 
Standard  Solution  of  Muriate  of  • 
Ammonia 4000  grains 
Pipe-clay  (passed  through  a sieve 
of  40  holes  to  the  inch)  . . 1000  , , 
1st  Distillation  of  the  resulting  Liquid — 
Grains.  Platinum  Salt.  Ammonia.  Per  Cent. 
168-19  gave  5-60  = -42686  or  *2538 
2nd  Distillation — 
170-01  gave  5-61  = *42770  or  *2543 
1st  Experiment  ....  *2538  per  Cent. 
2nd  ,,  ....  *2543  ,, 
Mean  of  the  2 Experiments  -25405  ,, 
100  grains  of  the  original  Liquid  contained  . *30600  grains  of  Ammonia. 
100  grains  of  the  resulting  Liquid  contained  *25405  , , ,, 
Loss  by  100  grains  of  liquid  ....  -05195  ,,  , , 
The  loss  by  the  whole  liquid  (4000  grains)  will  therefore  be  2-0/80 
grains,  which  being  absorbed  by  1000  grains  of  clay,  makes  the  absorption 
*2078  per  cent. 
In  the  next  experiment  the  relative  proportion  of  clay  is  still 
further  increased  : — 
Experiment  72. — Pipe-clay  and  muriate  of  ammonia: — 
Standard  Solution  of  Muriate  4000 
Pipe-clay  ...  . . 2000 
grains  ) p)igested  for  two  hours. 
9 3 ) 
1st  Distillation  of  the  resulting  Liquid— 
Grains. 
Platinum  Salt. 
Ammonia.' 
Per  Cent. 
176-42 
gave  4-65 
= *35452  or 
•20095 
2nd  Distillation — 
178*17 
gave  4-91 
= *37434  or 
•2101 
1st  Experiment  . . 
•20095  per  cent. 
2nd  ,,  . . *21010  ,, 
) ) 
| Digested  together  for  two  hours. 
Mean 
. *20552 
