July  i,  1892. .1 
THE  TRDP1CM.  AtmromTUmST. 
63 
stituted  for  another.  The  Pacific  mail  steamers 
gather  also  different  varieties  at  Panama  with  the 
same  confusion.  That  which  comes  from  Nicaragua 
is  called  Nicaragua  “sheet”  and  “scrap.”  The 
latter  comes  in  pieces  about  2£  feet  long,  weighing 
from  10  to  40  pounds.  In  the  gathering  of  rubber 
in  the  forest,  around  the  cuts  in  the  tree  a residuum 
is  left,  which  is  given  to  the  man  as  a perquisite, 
and  this  forms  “scrap,”  As  in  the  peculiar  mode 
of  gathering,  it  is  very  dry,  there  is  little  loss  in 
shrinkage,  and  this  quality  makes  it  a favourite  with 
manufacturers.  It  contains  some  bark,  but  not  so 
much  as  the  “ sheet."  The  sheet,  after  it  is  milled 
and  washed,  is  the  same  rubber  as  the  “scrap.” 
Both  are  cured  by  the  use  of  a vine  from  which 
a soapy  [?  alkaline]  substances  is  formed. 
There  is  another  grade  which  comes  from  Central 
America,  containing  a considerable  amount  of  ashes, 
due  to  its  being  smoked  over  the  latter.  It  comes 
in  thin  sheets  § to  f inch  thick.  It  is  a dry  rubber, 
there  not  being  so  much  loss  in  shrinkage ; but  it 
is  not  so  firm  as  the  other  grades,  and  it  is  diffi- 
cult to  work.  There  also  comes  from  Central  American 
ports  a rubber  which  is  chiefly  grown  in  New  Gra- 
nada, and  is  called  “ Carthagena  strip.”  It  is  from 
If  to  2 inches  thick,  and  there  is  a great  deal  of 
Band  and  d rt  in  it.  It  is  a black,  tough  rubber. 
Honduras  furnishes  a great  deal  of  rubber  of  the 
Tuno  sort,  which  is  found  in  many  other  sections 
of  Central  America.  Guatemala  ranks  low  in  the 
American  varieties,  containing  a resinous  substance 
which  gives  it  a tarry  appearance.  It  comes  in 
sheets  pressed  together.  There  is  a rubber  which 
comes  from  Angostura  as  good  as  Para.  When  cut 
it  is  found  to  contain  little  spots  of  white  as  large 
as  a pea.  Tuxpan,  Mexico,  once  sent  a fine  grade 
of  strip  rubber ; but  as  the  trees  have  been  destroyed 
by  cutting  them  down  instead  of  tapping  for  rubber, 
the  imports  from  there  are  now  very  small.  The 
rubber  is  gathered  by  scraping  from  the  bark. 
Guayaquil  comes  in  large  flakes  or  lumps  of  a 
whitish  colour  in  the  best  sorts,  the  inferior  sorts 
being  porous,  and  exuding  a black  liquid  which 
stains  the  knife  and  hands.  As  in  a great  many 
“ Centrals  ” the  name  is  often  confounded  with  the 
sorts. 
Esmeralda  comes  from  Guiana,  is  a strip  rubber, 
and  is  also  made  into  “ sausages.”  Some  brokers 
are  of  the  opinion  that  very  little  of  the  real  Es- 
meralda finds  its  way  to  America,  it  being  almost 
indistinguishable  from  other  grades.  It  brings  a 
high  price.  Certainly  little  of  it  finds  its  way  to 
Europe,  brokers  not  quoting  it  there.  A great  deal 
of  the  rubber  gathered  in  Columbia  finds  its  way 
to  the  Amazon  and  Para. 
In  rubber  from  Asia  the  Assams  probably  take  the 
lead,  and  are  rated  above  coarse  Para  in  price. 
There  are  three  or  four  grades,  the  lower  ones  being 
very  dirty  and  all  of  them  requiring  much  washing. 
There  are  two  grades  of  rubber  coming  from  Bor- 
neo. The  rubber  from  that  source  was  first  called 
a gutta,  on  account  of  its  geographical  location,  but 
this  error  was  a palpable  one,  and  soon  corrected. 
It  is  a white,  soft,  porous  or  spongy  rubber,  the 
ores  being  filled  with  salt  water  or  whey.  The 
_ etter  grade  is  a fair  rubber,  but  the  second  grade 
is  often  when  cut  almost  as  soft  as  putty  and  practi- 
cally worthless. 
Of  Africans  there  are  many  varieties.  The  favourite 
sorts  come  from  Madagascar.  The  pinky  sort  comes 
in  the  shape  of  round  balls,  weighing  1|  to  4 pounds. 
It  is  not  so  strong  as  fine  Para.  There  is  always 
a good  demand  for  it,  and  it  is  rarely  found  in  store, 
being  sold  “to  arrive.”  This  sort  comes  from  Tama- 
tave.  There  are  two  or  three  variations  in  quality 
of  Madagascars,  but  the  grade  called  “black”  comes 
from  Majunga,  is  exported  in  small  balls,  and  has 
a dark  colour  when  cut. 
From  the  West  Coast  of  Africa  there  are  many 
varieties,  the  best  coming  iu  the  shape  called  “ thim- 
bles,” which  are  square  pieces  one  inch  each  way. 
The  rubber  is  very  dry,  and  is  in  good  demand  by 
mechanical  goods  manufacturers.  It  is  very  strong 
rubber,  and  naturally  has  little  shrinkage.  Tongues 
are  shaped  as  their  names  indicate.  There  is  con- 
siderable shrinkage,  but  it  is  a very  good  rubber. 
There  is  also  a small  ball  rubber  about  lj  inches 
in  diameter.  It  cuts  white,  and  is  fairly  firm. 
Congo  ball  is  made  from  small  strips  of  rubber 
and  rolled  into  balls,  from  1 to  2£  inches  in  dia- 
meter. It  is  a firm  and  very  elastic  rubber,  but 
there  is  more  or  less  bark  in  it,  and  as  manufacturers 
do  not  always  have  proper  machinery  to  exclude  it, 
they  do  not  buy  readily. 
Sierra  Leone  comes  in  balls  3 to  4 inches  in  dia- 
meter, and  is  a very  fair  grade  of  rubber.  It  has 
a considerable  demand  from  boot  and  shoe  and 
mechanical  goods  men.  Like  all  West  Coast  rubbers 
it  reaches  us  by  way  of  Hamburg  or  Liverpool. 
The  finer  grade  of  Mozambique  is  called  “ white 
ball.”  It  resembles  Congo  ball  in  appearance,  and 
comes  in  about  the  same  shape.  The  “red  ball” 
is  mixed  with  a reddish  bark,  and  gets  its  name 
for  that  reason.  Oftentimes  both  varieties  of  “ball” 
will  be  found  filled  in  the  centre  with  bark.  The 
rubber  is  then  called  “ unripe  Mozambique,”  and 
sells  for  10  cents  less  per  pound. 
From  Liberia  comes  a lump  rubber.  There  are 
three  rivers  in  Liberia  from  which  rubber  is  gathered, 
but  it  is  all  assembled  at  the  common  mouth  and 
the  grades  are  not  kept  separately,  making  a class 
of  rubber  which  is  very  variable,  and  therefore  dis- 
liked by  manufacturers. 
There  is,  on  the  whole,  a growing  tendency  to- 
ward the  use  of  Africans,  and  in  this  is  a true  check 
on  the  price  of  Para.  In  Centrals  there  seems  to 
be  a falling  off  in  the  production  consequent  upon 
a scarcity  of  labour,  which  has  been  from  time  to 
time  drawn  into  internal  enterprises.  In  Europe  the 
stocks  of  Africans  are  always  larger  than  of  Para, 
and  a steady  growth  is  very  noticeable.— Keio  Bulletin. 
- -e- — 
SCIENCE  NOTES. 
It  is  generally  known  that  in  prehistoric  days 
Egypt  was  a wooded  country,  visited  by  great  deluges 
of  rain,  which  made  the  Lower  Nile  Valley  a broad 
estuary,  fed  by  streams  which  thundered  over  cliffs 
now  dry  and  solitary  amid  the  desert  sands.  The 
sequences  of  these  changes— which  resulted  in  the 
Nile  being,  except  at  the  period  of  the  annual  rise, 
when  it  covers  its  old  bed,  now  the  only  tillable 
part  of  the  country,  confined  to  the  comparatively 
narrow  channel  it  has  worn  for  itself — have  now 
been  worked  out  by  Mr.  Flinders  Petrie,  who  has 
done  so  much  for  the  archeology  of  Egypt.  By 
means  of  the  gravels,  river  mud,  and  other  remains 
he  has  traced  these  slow  revolutions,  which  the 
remains  of  man  in  places  where  man  could  no 
longer  live  prove,  in  some  cases  at  least,  to  have 
been  effected  since  man  inhabited  the  country, 
though,  as  the  weapons  found  are  rudely  chipped 
flints,  this  age  must  have  been  incalculably  remote. 
All  through  the  historic  period  complete  desiccation 
has  prevailed.  The  roads  marked  out  with  stones 
on  the  plains  at  Tel-el-Amara  in  1400  b.  c.  are  only 
destroyed  in  the  very  lowest  lines  of  the  water-courses. 
The  ancient  Egyptian  buildings  only  show  the 
effect  of  rare  storms  and  not  of  continued  rain, 
while  the  mud  deposits  throughout  this  age  are  at 
an  average  rate  of  four  inches  per  century.  What 
has  caused  this  desiccation  is  not  known.  There 
has  evidently  been  some  elevation  of  the  country. 
But  this  alone  will  not  account  for  the  absence 
of  rain.  As  Egypt  lives  by  the  Nile,  any  similar 
desiccation  in  the  mountains  of  Abyssinia  or  in 
Central  Africa  would  mean  absolute  ruin  to  the 
Delta  and  desertion  of  the  up-river  country. 
The  growth  of  the  trees  was  largely  dependent 
on  the  rainfall;  but,  at  the  same  time,  the  rainfall 
was  greatly  affected  by  the  trees.  By  aiding,  as  we 
know  they  do,  passing  clouds  to  discharge  their 
load,  and  by  protecting  springs,  they  kept  up  a 
supply,  and,  moreover,  pevented  the  showers  sweeping 
off  instead  of  sinking  into  the  soil.  Wherever  the 
timber  has  been  recklessly  destroyed  desiccation 
and  other  mischief  have  followed  in  its  train.  When 
the  Arab  conquerors  came  to  North  Africa  they 
