36 
[July  i,  1895. 
THE  TROPICAL  AGRICULTURIST. 
animal  and  vegetable  life  can  build  up  a thousand 
strange,  linstable  compounds  which  at  present  baffle 
the  scrutiny  of  mere  huiflan  chemistry.  Carbon  is 
peculiarly  the  element  of  the  organic  world.  Or- 
ganised material  is  almost  exclusively  made  up  of 
“carbon  compounds’’  ; but  although  the  w'orkings  of 
the  vital  force  which  moulds  them  are  still  as  great 
a mystery  as  Life  itself,  yet  we  know  that  the 
reign  of  the  law  of  chemical  combination  is  just 
as  assured  over  the  constituents  of  organised  as 
over  those  of  mineral  matter.  The  chemist  has  never 
yet  succeeded  in  forming  a single  organic  cell.  He 
is  as  far  off  as  ever  of  constructing  the  long-expected 
lifeless  protoplasm,  but  from  the  marvellous  deve- 
lopments of  the  past  40  years  he  has  the  most 
lively  hopes  of  some  day  building  up  a number  of 
those  organic  food  substances  which  at  present  have 
to  be  obtained  for  human  needs  by  the  sacrifice  of 
other  members  of  the  animal  creation.  Dr.  Arm- 
strong did  not,  however,  venture  to  forecast  the 
future  so  far  as  this.  He  contended  himself  with 
the  curious  illustrations  of  progress  offered  by  the 
wonderful  family  of  “sugars.”  While  the  Bi’itish 
house-wife  would  be  content  to  classify  the  sugars 
into  “lump,”  “moist,”  “ Demerara,”  and  so 
on,  the  British  chemist  would  surprise  her  with 
the  announcement  that  there  are  only  sixteen 
possible  sorts  of  sugar,  and  that  those  which 
she  has  enumerated  are  all  one  and  the 
same.  He  would  further  remark  that  only  eleven  out 
of  these  sixteen  have  at  present  been  met  with  in 
nature  or  prepared  in  the  laboratory — for  the  fact 
need  not  be  withheld  any  longer  that  the  artificial 
preparation  of  the  sugars  is  nowadays  one  of  the 
commonest  feats  of  commercial  chemistry.  Those 
other  five  “sugars”  the  chemist  is  as  certain  about 
as  he  is  of  his  own  existence.  They  probably  have 
never  yet  come  to  light  in  all  the  long  history  of 
the  globe  we  inhabit,  but  the  chemist  is  serenely 
certain  of  their  possibility,  and  will  undoubtedly 
amuse  himself  one  day  by  introducing  them  in  a 
concrete  form  to  the  world.  The  main  interest  of  the 
sugars  is  the  proof  they  afford  us  of  the  wonderful 
practicability  of  the  atomic  theory.  They  may  be 
all  regarded  as  composed  of  carbon  and  water,  but  the 
secret  of  their  diverse  natures  lies  in  the  fact  that 
these  materials  are  built  up  either  in  different  pro- 
portions, or,  if  in  the  same  proportions,  then  in 
different  ways.  The  atoms  of  carbon,  oxygen,  and 
hydrogen  are  like  so  many  toy  bricks,  each  fitted  with 
mortices  and  tenons,  so  that  they  can  be  built  up 
into  edifices  of  varying  shape.  The  hydi-ogen  bricks 
have  only  one  point  of  attachment,  the  oxygen  have 
two,  and  the  carbon  four.  A carbon  brick  requires 
either  four  hydrogen  bricks  or  two  oxygen  bricks  to 
satisfy  all  its  links,  or  it  may  have  two  hydrogen 
And  one  oxygen  bricks  attached.  Still  more  strangely. 
It  may  be  compelled  to  go  into  partnership  with 
only  two  hydrogen  bricks,  but  in  that  case  the 
chemist  knows  that  the  two  spare  links  of  the  carbon 
brick  are  then  joined  to  each  _ other,  for  every 
link  must  in  some  way  have  a partner.  But  the 
business  gets  still  more  complex  when  instead 
of  one  carbon  brick  we  have  six  of  such  bricks  or 
various  multiples  of  six,  as  in  the  case  of  the 
sugars.  Ur.  Arnisti'ong  illustrated  this  process  of 
“ atom  linking,”  not  by  toy  bricks,  but  with 
coloured  balls  with  holes  and  pegs.  Here  we  may 
have  a whole  line  of  carbon  atoms  strung  together 
by  two  out  of  each  of  their  four  arms,  and  pre- 
senting on  either  side  spare  arms  for  the  attach- 
ment of  oxygen  and  hydrogen  atoms  in  various  sym- 
nietrical  and  unsymmetrical  ways.  It  soon  ceases  to  be 
a case  of  combining  single  atoms,  and  passes  into  one 
of  grouping  together  special  compound  sets  called  “ radi- 
cals,” which,  owing  to  this  remarkable  handiness  of 
the  carbon  atom,  are  looked  upon  by  the  organic  che- 
mist just  in  the  same  light  as  the  inorganic  clicmisl 
looks  upon  his  simple  atoms.  Hvery  variation  in  the 
grouping  means  a new  and  probably  quite  dis- 
tinct cnemical  compound,  and  yet  not  only  are 
the  ingredients  the  same,  but  may  actually  oe  in 
precisely  identical  proportions.  Then,  fiutlicr,  wc 
have  another  strange  thing  in  tho  so-called  “law 
of  symmetry.”  These  carbon  compounds  vary 
accoroiug  as  the  house  of  bricks  built  up  is 
symmetrical  or  unsymmetrical.  You  may  have  exactly 
trie  same  number  of  each  sort  of  bricks  in  the  house, 
but  if  you  have  given  it  a lop-sided  appearance,  then 
a solution  of  the  sugar  produced  will  twist  out  of  its 
path  a ray  of  polarised  light.  Some  compounds 
possess  a right-handed,  others  a left-handed  twist, 
l^asteur  found  out  that  he  could  prepare  two  sorts 
of  tartaric  acid,  one  natural,  the  other  artificial.  Both 
seemed  practically  identical,  yet  Nature’s  tartaric 
acid  gave  a left-handed  twist  to  polarised  light  while 
Pasteur’s  gave  a right-handed.  Later  investigations 
have  shown  that  this  curious  I’ule  of  lop-sidedness 
seems  to  run  throughout  the  whole  of  organic 
chemistry,  and  that  compounds  may  exist  which  are 
the  image  of  each  other,  just  like  a right-hand  glove 
is  an  image  of  its  left.  We  have  endeavoured  to 
give  some  faint  conception  for  popular  purposes  of 
the  matter  which  Dr.  Armstrong  dealt  with.  Know'- 
ing  that  through  investigation  such  as  this  the  word 
is  indebted  to  the  discovery  of  almost  every  new 
compound  of  value  that  modern  chemistry  has  given 
us,  there  will  be  no  difficulty  in  agreeing  with  him 
as  to  its  high  value  and  importance. — Daily  Chronicle. 
ESSENTIAL  OII.S  IN  THEIR  RELATION 
TO  THE  BRITISH  I’HARMA('OP(EIA 
AND  TRADE. 
By  John  C.  Umney. 
Cinnanion  Oil. — In  regard  to  this,  Mr.  Umney  sub- 
mitted a table  of  results  of  analysis  of  bark  and  leaf 
oils,  showing  that  the  former  are  always  under  s.g. 
1030,  audpure  leaf  oil  above  s'g,  1-050,  so  that  the  ad- 
dition of  the  latter  to  the  former  raises  the  density, 
which  is  the  condition  that  obtains  in  regard  to  Ceylon 
cinnamon-bark  oil.  The  bark  oil  is  further  distinguished 
by  having  cinnamic  aldehyde  as  the  principal  constitu- 
ent (38  to  70  per  cent  in  samples  examined),  while  the 
leaf  oil  contains  chiefly  eugenol  (80  to  85  per  cent.), 
of  which  the  bark  oil  contains  only  4 to  8 per  cent. 
The  optical  rotation  of  the  pure  oils  is  practically 
7iil  but  leaf  oils  are  dextro-rotatory.  The  following 
characters  and  tests  seem  those  suitable  for  a new 
British  Pharmacopojia : — Sp.  gr.  at  15°  C.,  1-024  to 
1-030.  Optically  inactive.  One  drop  of  the  oil  in  5 
drops  of  rectified  spirit  should  not  give  more  than 
a pale-green  coloration  with  fen-ic  chloride.  The  oil 
should  not  solidify  with  a solution  of  caustic  potash. 
When  treated  with  solution  of  bisulphite  of  soda  so- 
lution, it  should  not  yield  more  than  45  per  cent, 
of  non-aldehydes,  equal  to  65  per  cent  of  cinnamic 
aldehyde. 
Citronella  Oil. — No  opinion  was  expressed  as  to  the 
officialising  of  this  oil,  but  the  following  were  men- 
tioned as  the  factors  for  the  pure  oil  ; — Specific 
gravity  not  less  than  -887,  and  the  oil  is  soluble  in 
10  parts  of  80-per  cent,  alcohol.  — Chemist  and  Dnujyist. 
A TALK  ABOUT  TEA  AND  TEA 
PLANTING. 
Mr.  Ghristison,  late  of  Darjeeling,  gave  a very  in- 
teresting lecture  at  St.  James’s  Hall  (Church 
of  Scotland),  East  Dulwich  Green,  on  Indian  tea 
aud  tea  planting  in  Darjeeling,  to  a large  audience. 
The  room  was  tastefully  decorated  with  the  D.ar- 
jeeling  planters’  and  the  Nepaulese  flags,  and  tho 
lecture  was  illustrated  by  a number  of  lantern  slides 
descriptive  of  all  phases  of  planter  life  in  Darjeel- 
ing. Mr.  Ghristison,  whose  knowledge  of  all  that  con- 
cerns tea  cultivation  is  founded  on  the  experience  of  a 
lifetime  spent  as  a tea  planter,  gave  a most  inter- 
esting account  of  the  origin,  history,  and  cultiva- 
tion of  tea. 
Tl'.A  J'L.\N-riNO  AS  AN  OCCL’l’ATION. 
The  latter  portion  of  his  lecture  Mr.  Ghristison 
devoted  to  tlie  question  of  tea  planting  as  an  occu- 
pation for  our  young  men,  and  on  this  point  he 
spoke  with  his  usual  candour.  In  tho  course  of  his 
remarks  ho  said  : There  is  one  tO))ic  more  I feel  I 
ought  to  toucdi  upon  beloro  leaving  this  branch  of 
my  subject.  1 have  very  often  boon  aiipoiiled  to 
for  advice  by  young  men,  aud  the  friends  of  young 
