448 
ORGANIC  MATTER  OF  THE  AIR. 
Thames  at  City,  no  odor  perceived  after  the  warmest 
weather  of  1858    584 
Thames  at  Lambeth      .......  43-2 
"         Waterloo  Bridge   43-2 
London  in  warm  weather  (six  experiments)     .       .       .  29.2 
"      after  a  thunder-storm       .....  12*3 
In  the  fields  S.  of  Manchester   13»7 
"          N.  of  Highgate,  wind  from  London      .       .  12-3 
Fields  during  warm  weather  in  N.  Italy         .       .       .  6-6 
Moist  fields  near  Milan   18-1 
Open  sea,  calm  (German  Ocean,  60  miles  from  Yarmouth)  3-3 
Hospice  of  St.  Bernard,  in  a  fog    .       .               .       .  2-8 
N".  Lancashire        .......  about  same 
Forest  at  Chamouni       .......  2-8 
Lake  Lucerne       ........  1-4 
The  first  experiments  undertaken  were  in  Manchester,  and  the 
average  amount  obtained  was  in  the  city  about  50,  gradually 
diminishing  in  moving  towards  the  country  until  it  was  found  in 
the  fields  at  13  ;  on  passing  a  sewer  stream  about  a  mile  from 
the  outskirts,  the  amount  rose  to  83.  The  atmosphere  on  the 
Thames  was  not  measured  whilst  at  its  worst,  but  immediately 
afterwards  ;  when,  however,  it  had  ceased  to  affect  the  senses  of 
most  persons  at  least,  the  amount  was  very  high,  viz.  58.  I  was 
anxious  to  know  how  far  the  Thames  affected  the  atmosphere  of 
London,  and  tried  some  experiments  :  the  result  was  that  the  in- 
fluence appeared  to  cease  almost  immediately  ;  the  fact  of  a  block 
of  houses  standing  in  the  way  was  enough  to  prevent  the  in- 
fluence ;  when  at  the  worst  this  may  not  have  been  the  case  ;  to 
arrive  at  the  other  side  of  the  block,  the  vapor  would  generally 
require  to  rise  high,  so  that  it  would  become  mixed  with  a  great 
deal  of  air.  The  amount  obtained  in  a  few  trials  in  the  streets 
of  London  was  22  to  34 ;  going  on  to  Highgate,  the  numbers 
sank  from  33  to  24;  on  descending  the  north  side  of  Highgate 
Hill  a  distinct  change  was  perceived,  the  numbers  being  18;  the 
wind  meantime  was  blowing  from  the  city  :  the  few  experiments 
made  in  the  fields  in  summer  gave  10  to  12.  The  numbers  6  to 
18  were  obtained  in  Switzerland  and  Lombardy.  The  moist 
fields  around  Milan  gave  18 ;  when  the  water  passes  off  the  rice 
