36 
JOURNAL  OF  HORTICULTURE  AND  COTTAGE  GARDENER. 
July  13,  1899. 
flowers  are  most  acceptable  where  buttonhole  flowers  are  in  demand. 
It  is  a  good  grower,  and  thrives  well  in  the  usual  compost, 
suspended  in  small  pans,  in  a  warm  Dendrobium  house.  It  must  be 
watered  very  cautiously,  as  it  is  apt  to  decay  at  the  base  of  the 
pseudo-bulbs.  It  inherits  the  peculiar  odour  of  medicinal  Rhubarb 
that  characterises  its  parents. 
Dendrobium  Dearei. 
This  handsome  and  desirable  species  is  worth  bestowing  consider¬ 
able  pains  and  attention  upon  to  produce  it  in  the  best  possible 
manner.  It  is  not  one  of  the  easiest  to  grow — in  fact,  a  great  many 
fail  entirely  with  it;  but  when  well  done  few  Orchids  command  more 
attention.  It  is  a  heat-loving  plant  from  the  Phillipine  Islands,  where 
it  was  discovered  by  Col.  Deare  in  1882,  and  has  been  imported  in 
considerable  quantities  since,  and  at  the  present  time  is  fairly  plentiful, 
and  well  within  the  reach  of  anyone.  I  find  it  grows  well  in  small 
pans,  as  I  said  before,  in  the  warmest  house  ;  it  detests  much  compost 
about  its  roots,  and  what  is  used  must  be  of  the  very  best.  I  employ 
one-half  rough  peat,  from' which  all  the  fine  particles  have  been  taken  ; 
the  other  half  clean  live  sphagnum  moss,  in  which  a  few  broken  clean 
crocks  are  added.  It.  delights  in  an  abundant  supply  of  atmospheric 
and  root  moisture  whilst  growing,  and  when  not  in  flower  an  occasional 
syringing  will  do  no  harm  if  clean  soft  water  is  at  command.  The 
foliage  should  be  carefully  watched  for  a  small  white  scale,  which 
unless  kept  under  will  do  irremediable  damage — in  fact,  should  the 
grower  decide  to  start  with  imported  plants,  great  care  should  be 
taken  that  they  are  all  thoroughly  clean  before  they  are  allowed  to  be 
placed  in  their  pans. — J.  Barker,  Hessle. 
SILICO-FLUORIDE  OF  AMMONIUM. 
When  you  were  first  good  enough  to  allow  me  to  draw  attention 
to  the  use  of  the  silico-fluoride  of  ammonium  in  the  Journal  of  Horti¬ 
culture  (21st  October,  1897),  you  also  printed  the  opinion  of  an  expert 
in  horticultural  chemistry  as  follows : — “  I  believe  the  material 
suggested  by  your  correspondent  is  possessed  of  no  insecticidal  value 
apart  from  its  acidity,  and  consequent  danger  to  the  plant.”  As 
sufficient  time  has  now  elapsed  to  allow  of  a  complete  investigation  of 
this  matter,  perhaps  you  will  permit  me  to  state  the  conclusions  at 
which  I  have  arrived. 
The  silico-fluoride  of  ammonium,  when  prepared  by  any  process  of 
sublimation,  as  the  samples  I  sent  were,  gives  with  water  a  decidedly 
acid  solution.  A  solution  of  fluosilicic  acid  in  water  was  therefore 
completely  neutralised  with  ammonia,  filtered,  and  evaporated  to 
dryness.  The  crystals  were  redissolved  in  water,  and  the  solution 
filtered  ;  this  solution  was  quite  neutral  to  litmus. 
A  quantity  of  an  aqueous  solution  of  the  sublimed  silico-fluoride, 
which  was  strongly  acid  to  litmus,  was  then  evaporated  to  dryness. 
The  crystals  so  produced  were  redissolved  in  water  and  filtered.  The 
solution  thus  prepared  was  no  longer  acid,  but  entirely  neutral. 
The  question  then  arose,  To  what  is  the  acidity  due  ?  I  placed 
about  a  pint  of  the  acid  solution  in  a  glass  bottle;  after  standing  for 
six  months  there  was  no  sign  of  the  bottle  being  corroded,  which  would 
have  been  the  case  if  the  acidity  were  caused  by  free  fluoric  acid. 
The  only  other  acid  capable  of  existing  in  such  a  solution  is  silicic 
(H4Si04).  Such  an  acid  is  immediately  precipitated  by  adding 
excess  of  ammonia  to  the  silico-fluoride  of  ammonium,  fluoride  of 
ammonium  being  simultaneously  produced.  It. is  easy,  therefore,  to 
understand  how  the  process  of  sublimation  produces  an  acid  salt. 
The  slightest  irregularity  in  the  dissociation  by  heat  of  the  substance, 
or  in  the  reassociation  of  those  constituents  during  condensation,  may 
well  give  rise  to  a  temporary  excess  of  ammonia,  with  the  immediate 
formation  of  soluble  silica.  This  silica  would  give  an  acid  reaction 
with  litmus. 
Soluble  silica  is  not,  however,  “  dangerous  to  plants,”  acid  though 
it  may  bo.  Probably  all  of  your  readers  will  agree  that,  within  reason¬ 
able  limits,  the  more  soluble  silica  a  plant  comes  in  contact  with,  the 
better  for  the  plant.  And  I  cannot  help  thinking  that,  from  a 
mammal  point  of  view,  one  great  advantage  in  using  silico-fluoride  of 
ammonium  is  this — viz.,  that  on  decomposing  in  soils  it  gives  rise  not 
only  to  ammonia  (very  possibly  in  the  form  of  a  carbonate),  but  also 
to  a  large  per-centage  of  soluble  silica. 
In  order  to  test  the  matter  fully  I  have  sent  considerable  quantities 
(up  to  7  lbs.)  of  both  the  acid  and  the  neutral  salt  to  correspondents 
in  this  country  and  abroad.  As  far  as  I  can  judge  there  does  not 
appear  to  be  any  practical  difference  in  the  behaviour  of  either 
substance,  and  this  was  to  be  expected,  for  after  all  the  acidity  was 
bound  to  be  very  trifling. 
I  cannot  help  concluding,  therefore,  with  submission  to  the  wider 
practical  knowledge  of  more  experienced  horticultural  observers  than 
myself,  that  the  beneficial  action  of  the  silico-fluoride  of  ammonium 
as  a  manure  is  due  to  the  highly  nutritious  products  of  its  decomposi¬ 
tion  in  soils ;  as  an  insecticide,  to  the  fact  that  it  directly  attacks  and 
combines  with  the  substances  out  of  which  insects  are  formed. — W.  M. 
SHOWS. 
IIITCHIN. — July  5th. 
The  annual  show  was  held  in  glorious  weather,  and,  as  usual  here, 
the  Roses  were  the  mainstay  of  the  exhibition.  The  entries  in  the  large 
classes  were  hardly  as  numerous  as  last  year,  but  the  local  competitors 
were  much  keener  than  usual. 
Three  competitors  staged  for  the  premier  Rose  cla9s,  which  consisted 
of  forty-eight  trusses,  distinct.  Messrs.  Harkness  &  Son,  Bedale  and 
Ilitchin,  were  first  with  good  fresh  boxes.  The  varieties  wore — back 
row  :  Etienne  Levet,  Caroline  Testout,  Camille  Bernardin,  Mons.  Soman, 
Ulrich  Brunner.  Koiserin  Augusta  Victoria,  Gustave  Piganeau,  Her 
Majesty,  Captain  Hayward,  Madame  Montet,  Comtcsse  d’Oxford, 
Souvenir  d’Elise  Vardon,  Francois  Michelon,  Pride  of  Waltham,  John 
Pawle,  and  Mrs.  J.  Laing.  Middle  row  :  Merveille  do  Lyon,  Earl 
Dufferin,  Madame  Hoste,  Annie  Laxton,  Medea,  Duchesse  de  Morny, 
Catherine  Mermet,  Heinrich  Schultheis.  Mrs.  Sandford,  Marie  Baumann, 
The  Bride,  Louis  Van  Houttc,  Marechal  Niel,  S.  M.  Rodocanachi, 
Madame  Cusin,  and  La  France  ;  while  the  front  row  was  represented  by 
Souvenir  d’un  Ami,  Viscountess  Folkestone,  Charles  Darwin,  Mar¬ 
chioness  of  Londonderry,  Mrs.  W.  .T.  Grant,  Rubens.  Madame  G.  Luizet, 
Marie  Van  Houtte,  Madame  E.  Verdier,  Innocente  Pirola  Duke  of  Fife, 
Hon.  E.  Gifford,  Alfred  Colomb,  Maman  Cochet,  Dupuy  Jamain,  and 
Anna  Ollivier.  Messrs.  Burrell  &  Co.,  Cambridge,  were  second  with 
good  flowers  of  Ladv  Mary  Fitzwilliam,  Her  Majesty,  La  France, 
Madame  E.  Verdier,  Caroline  Testout,  Robert,  Duncan.  Mrs.  J.  Laing, 
Gustave  Piganeau,  Souvenir  d’Elise  Vardon.  Kaiserin  Augusta  Victoria, 
and  Helen  Keller,  while  Messrs.  G.  &  W.  H.  Burch,  Peterborough, 
were  third. 
The  same  number  of  entries  were  staged  for  twelve  blooms,  six  dark 
and  six  light,  Messrs.  Harkness  &  Son  were  well  ahead  with  good 
Captain  Hayward  and  Mrs.  John  Laing.  Messrs.  G.  &  W.  H.  Burch 
were  s  cond  with  Ulrich  Brunner  and  good  Kaiserin  Augusta  Victoria ; 
and  the  Rev.  W.  II.  Jackson,  Stagsden  Vicarage,  Bedford,  third  with 
Captain  Ha3’ward  and  Caroline  Testout. 
Coming  to  the  Tea  and  Noisette  classes  we  found  stronger  competition, 
bu»  Messrs.  Harkness  &  Son  were  still  to  the  fore,  with  a  bright,  clean 
exhibit.  The  varieties  were  Madame  Iloste,  Maman  Cochet,  Marie  Van 
Houtte.  Niphetos,  Souvenir  d’Elise,  Madame  de  Watteville,  Souvenir  d’un 
Ami,  Hon.  E.  Gifford,  Catherine  Mermet,  Mardchal  Niel,  Cleopatra,  The 
Bride,  Etoile  de  Lyon,  Anna  Ollivier,  Jules  Finger,  Madame  II.  Jamain, 
Caroline  Kuster,  and  Corinna.  Messrs.  Burrell  &  Co.  obtained  the 
second  prize  with  rather  smaller  blooms.  The  best  were  Bridesmaid, 
Madame  Cusin,  Niphetos,  Madame  Hoste,  and  Catherine  Mermet  ;  while 
the  Rev.  W.  H.  Jackson  was  third  with  clean  fresh  flowers. 
In  the  class  for  eighteen  single  trusses  the  entries  dropped  to  two, 
but  both  were  pood.  Mr.  E.  B.  Lindsell,  Bearton,  Ilitchin,  secured  the 
first  position  with  an  even  display.  The  varieties  were  La  France, 
Gustave  Piganeau.  White  Lady,  FranQois  Michelon.  Mrs.  S.  Crawford, 
Ulrich  Brunner.  Prince  Arthur,  Her  Majesty,  Earl  Dufferin,  Madame 
Hoste,  Marie  Baumann,  Marchioness  of  Londonderry,  S.  M.  Rodo¬ 
canachi,  Louis  Van  Houtte,  Viscountess  Folkestone,  Due  d’Orleans, 
Merveille  de  Lyon,  and  Helen  Keller  ;  the  Rev.  W.  H.  Jackson  proved 
a  good  second.  His  best  blooms  were  La  France.  Kaiserin  Augusta 
Victoria.  Her  Majesty,  Corinna,  and  Madame  Gabriel  Luizet. 
In  the  class  for  twelve  Teas  or  Noisettes,  the  Rev.  W.  H.  Jackson  was 
able  to  turn  the  tables  on  Mr.  E.  B.  Lindsell  with  a  good  even  twelve. 
The  varieties  were  Bridesmaid,  Souvenir  d  Elise,  Maman  Cochet, 
Souvenir  de  S.  A.  Prince,  Elise  Fugier,  Comtesse  de  Nadaillac,  The 
Bride,  Ethel  Brownlow,  Catherine  Mermet,  Madame  Hoste,  Madame 
Cusin,  and  Ernest  Metz.  In  Mr.  Lindsell  s  box  there  were  good 
representative  flowers  of  The  Bride,  Anna  Ollivier,  Caroline  Kuster,  and 
Madame  Hoste. 
The  growers  of  less  than  1000  plants  staged  three  boxes  in  the 
class  for  twelve  blooms,  distinct.  Mr.  W.  0.  Times,  Ilitchin,  was 
placed  first  with  a  good  stand.  The  varieties  were  Marie  Baumann, 
Mrs.  J.  Laing,  Captain  Hayward,  Francois  Michelon,  Mrs.  S.  Crawford, 
Dr.  Andrv,  Marchioness  of  Londonderry,  Alfred  Colomb,  Gustave 
Piganeau,  Innocente  Pirola,  Tom  Wood,  and  Madame  Cusin.  Mr.  W. 
Kingston,  Bedford,  was  a  close  second  with  typical  flowers  of  Ulrich 
Brunne'-,  Mrs.  J.  Laing,  Francois  Michelon.  and  Madame  Hoste  ;  while 
Mr.  G.  Moules,  Hitchin,  brought  up  the  rear. 
The  class  for  six  Teas  or  Noisettes  proved  to  be  the  most  popular  as 
far  as  the  competitors  were  concerned,  but  Mr.  A.  F.  Albon.  Hitchin, 
outdistanced  the  others  with  a  fine  exhibit.  Hi9  blooms  were  Catherine 
Mermet,  The  Bride,  Anna  Olbvier,  Madame  Hoste,  Caroline  Kuster, 
and  Marie  Van  Houtte.  Mr.  W.  O.  Times  followed  with  good  flowers 
of  Franeisca  Kruger,  Souvenir  de  S.  A.  Prince,  and  The  Bride  ;  and  Mr. 
J.  T.  Hunt  third. 
There  were  eleven  ompetitors  for  six  trusses,  distinct,  Mr.  Moules 
being  first  with  a  grand  six.  The  varieties  were  Mrs.  J.  Laing, 
Marie  Baumann,  Caroline  Testout,  Madame  Hoste,  Catherine  Mermet, 
and  The  Bride.  Mr.  J.  T.  Hunt  was  second  with  good  blooms 
of  The  Bride  and  Mrs.  J.  Laing  ;  while  Mr.  H.  Hunt  was  third.  For 
six  trusses,  one  variety.  Mr.  W.  Kingston  was  first  with  goM  blooms  of 
Francois  Michelon.  Mr.  G.  Moules  was  second  with  Mrs.  J.  Laing;  and 
Rev.  W.  H.  Jackson  third.  For  six  Teas  or  Noisettes,  one  variety,  the 
Rev.  W.  H.  Jackson  was  first  with  Souvenir  de  S.  A.  Prince  ;  Mrs. 
Moulden  followed  with  the  Hon.  Edith  Gifford  ;  and  Mr.  W.  Kingston 
third  with  Caroline  Kuster.  The  medal  for  the  best  Hybrid  Perpetual 
