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Erratum 
Page  320,  line  22,  for  12  ounces  read  12  grains 


Tissnndier's  Photography. 


PHOTOGRAPHY 


LONDON  :    I'KINTED    BV 

SPOTTISWOODE      AND      CO.,      NEW-STKEET      SQUARE 

AND    PARLIAMENT   STREET 


/- 


HISTORY   AND    HANDBOOK 


OF 


PH  OTOGR A PH Y 

Translated  from  the  French  of 

GASTON     TISSANDIER 


EDITED    BY 

J.  THOMSON,  F.R.G.S. 

AUTHOR  OF    'ILLUSTRATIONS  OF  CHINA  AND  ITS  PEOPLE,'    'THE    STRAITS  OF 
MALACCA,  INDO-CHINA,  AND  CHINA,'  ETC. 


WITH  UPWARDS  OF  SEVENTY  ILLUSTRATIONS 


LONDON 
SAMPSON,  LOW,  MARSTON,  LOW,  &  SEA  RLE, 

CROWN    BUILDINGS,  l88    FLEET    STREET 
1876 


NEW     YORK 

S  C  O  \'  I  L  L     MANUFACTURING     COMPANY 

Nos.  419  «!y:  421   Broome.  Street 

1877 


P  R  K  FACE. 


Arago  placed  the  daguerreotype  amongst  the  most 
remarkable  conquests  of  genius,  by  the  side  of  the  tele- 
scope and  the  electric  battery.  And  indeed  to  every 
enlightened  mind,  the  fixing  of  the  image  or  picture  of 
the  *  camera  obscura '  or  dark  chamber  by  chemical  agents, 
must  appear  a  great  event  in  the  history  of  progress. 
An  art  so  novel,  capable  of  producing  at  the  very  outset 
such  strange  results,  at  once  stamped  itself  as  something 
grand,  extraordinary,  as  a  work  full  of  vitality  and 
vigour. 

Franklin's  words  with  respect  to  the  balloon,  *  It  is 
the  infant  just  beginning  to  grow,'  could  not  have  been 
applied  to  the  daguerreotype,  which  has  grown  and 
prospered  with  such  rapidity  as  to  have  had,  $o  to 
speak,  no  childhood  or  growth  at  all.  The  daguerreo- 
type is  one  of  the  latest  of  the  prodigies  of  modern 
science  ;  it  was  discovered  in  1838. 

The  daguerreotype,  as  soon  as  born,  transformed 
itself  into  the    photograph.     Hardly  forty   years    have 


iv  PREFACE. 


elapsed  and  the  new  invention  has  spread  abroad  and 
become  so  well  known,  that  it  has  penetrated  everywhere, 
in  every  civilised  country,  into  the  dwellings  of  the  poor 
as  well  as  of  the  rich.  Unhappy  indeed  is  he  who  can- 
not have  recourse,  for  the  picture  of  that  which  he  loves; 
to  photography,  that  sublime  and  beneficent  art  which 
gives  us  at  such  little  cost  the  human  visage  in  its  exacti- 
tude, which  presents  to  our  eyes  as  in  a  mirror  the  scenery 
of  distant  lands,  which  lends  its  aid  to  all  the  sciences, 
which  accompanies  the  astronomer  into  the  depths  of  the 
heavens,  the  micrographer  into  the  invisible  world,  and 
which  even  comes  to  the  assistance  of  the  besieged  city, 
reducing  its  messages  to  the  easy  burden  of  a  bird  ! 

In  studying  the  plan  of  this  work,  the  author  was 
impressed  with  the  importance  of  the  subject ;  in  writing 
it^  he  experienced  a  deep  admiration,  which  it  has  been 
his  aim  to  impart  to  the  reader.  He  has  endeavoured  to 
make  his  sketch  at  once  a  practical  guide  to  the  amateur 
photographer,  and  an  attractive  and  instructive  history, 
as  is  that  of  all  scientific  conquests  when  narrated  with 
truth  and  sincerity. 

In  this  second  edition  which  follows  so  closely  on  the 
first,  some  gaps,  which  the  development  of  the  art 
rendered  in  some  degree  inevitable,  have  been  filled  up 
from  the  large  number  of  new  facts  which  have  come 
to  light. 

G.  T. 


CONTENTS. 


PART    I. 

THE  HISTORY  OF  PHOTOGRAPHY 


CHAPTER  I. 

THE   ORIGIN   OF   PHOTOGRAPHY. 

PACK 

J.  B.  PORTA  AND  THE  DARK  ROOM — FABRICIUS  THE  ALCHEMIST — 
LUNA  CORNEA  —  PROFESSOR  CHARLES'S  SILHOUETTES  —  WEDG- 
WOOD,   HUMPHRY    DAVY,    AND  JAMES   WATT  ....  I 

CHAPTER   II. 

DAGUERRE. 

DEGOTTI  THE  SCENE  PAINTER — EARLY  LIFE  OF  DAGUERRE — IN- 
VENTION OF  THE  DIORAMA — THE  CAMERA  OR  DARK  ROOM — 
CHEVALIER  THE  OPTICIAN— THE  HISTORY  OF  AN  UNKNOWN — 
FIRST   LETTER   OF   DAGUERRE   TO   NIEPCE I4 

CHAPTER   III. 

NICfiPHORE   NIEPCE. 

THE  TWO  BROTHERS  NIEPCE — THEIR  YOUTH — THEIR  WORKS — THE 
PYRELOPHORE  — HYDRAULIC  MACHINE— NICfiPHORE'S  RESEARCHES 
IN    HELIOGRAPHY— RESULTS   OBTAINED 26 


VI  CONTENTS. 


CHAPTER  IV. 

THE   NIEPCE-DAGUERRE   PARTNERSHIP. 

PAGE 

CORRESPONDENCE  EXCHANGED  BETWEEN  THE  TWO  INVENTORS  — 
DISTRUST  AND  RESERVE  OF  NIEPCE — HIS  JOURNEY  TO  PARIS— 
HIS  INTERVIEWS  WITH  DAGUERRE — HIS  JOURNEY  TO  LONDON 
— ACT   OF   PARTNERSHIP — DEATH    OF   NIEPCE      .  .  .  .      40 

CHAPTER  V. 

THE   DAGUERREOTYPE. 

DAGUERRE'S  RESEARCHES  AND  STUDIES— HE  CEDES  HIS  INVENTION 
TO  THE  STATE — ARAGO  AND  THE  DAWN  OF  PHOTOGRAPHY — 
A  BILL  LAID  BEFORE  THE  HOUSE — REASONS  FOR  ITS  BEING 
PASSED — MEETING    OF   THE   ACADEMY   OF   SCIENCES,  AUGUST  lO, 

1839 53 

CHAPTER  VI. 

THE   PROGRESS  OF  A   NEW   ART. 

THE  DAGUERREOTYPE  PROCESS — ACCELERATING  SUBSTANCES — IM- 
PROVED LENSES — PORTRAITS — FIXING  AGENTS — DISCOVERY  OF 
PHOTOGRAPHY    ON    PAPER   BY   TALBOT — M.    BLANQUART-EVRARD      64 

CHAPTER  VII. 

PHOTOGRAPHY. 

SIR   JOHN    HERSCHEL — HYPOSULPHITE   OF   SODA— NIEPCE    DE  SAINT- 

VICTOR'S    NEGATIVE    ON    GLASS— GUN-COTTON   AND    COLLODION      79 


CONTENTS.  VU 


PART    II. 

THE   OPERATIONS  AND  PROCESSES  OF 
PHOTOGRAPHY. 


CHAPTER   I. 

THE   STUDIO  AND  APPARATUS. 

I'AGE 

ARRANGEMENT  OF  A  GOOD  STUDIO— THE  DARK  ROOM — TERRACE 
—  SITTING  ROOM — THE  INFLUENCE  OF  LIGHT — ARRANGEMENTS 
FOR  LIGHTING  THE  OBJECT  TO  BE  PHOTOGRAPHED— THE  APPA- 
RATUS— LENSES   AND    CAMERAS 89 

CHAPTER    II. 

THE    NEGATIVE. 

MANIPULATION  OF  THE  PHOTOGRAPH— CLEANING  THE  PLATE — 
COATING  THE  PLATE  WITH  COLLODION— PLACING  IT  IN  THE 
SILVER  BATH — EXPOSURE  IN  THE  CAMERA — DEVELOPMENT, 
FIXING   AND    VARNISHING I05 

CHAPTER    III. 

THE    POSITIVE   ON    PAPER. 

PRINTING  ON  PAPER— OF  THE  NATURE  AND  QUALITIES  OF  PHOTO- 
GRAPHIC PAPERS  —  VIGNETTES — EXPOSURE  TO  THE  LIGHT — 
TONING— FIXING  — ROLLING    THE    PROOFS 122 

CHAPTER    IV. 

THEORY    AND    PRACTICE. 

EXPLANATION  OF  PHOTOGRAPHIC  OPERATIONS— NECESSITY  OF  LONG 
PRACTICE — MODIFICATIONS  IN  PROCESSES  REQUIRED  BY  DIF- 
FERENT SORTS  OF  PHOTOGRAPHY— PHOTOGRAPHY  AND  TRAVEL 
—  LANDSCAPES  —  SKIES  —  PORTRAITS  —  INSTANTANEOUS  PHOTO- 
GRAPHY            .       .     132 


Vlil  CONTENTS. 


CHAPTER    V. 

RETOUCHING. 

PAGE 

ACCIDENTS  WITH  NEGATIVES  AND  PROOFS— METHOD  OF  REMEDYING 
THE  SAME — RETOUCHING  THE  NEGATIVE — IMPERFECTIONS  IN 
THE  POSITIVE— RETOUCHING  PHOTOGRAPHIC  PROOFS  WITH 
INDIAN  INK— COLOURING  PHOTOGRAPHS  —PHOTOGRAPHIC  CARI- 
CATURES            ■    .  .  .    141 

CHAPTER   VI. 

ENLARGEMENT    OF    PROOFS, 

APPARATUS  EMPLOYED  FOR  ENLARGING  NEGATIVE  PROOFS — WOOD- 
WARD'S SYSTEM — MONCKHOVEN'S  APPARATUS— UNIVERSAL  SOLAR 
CAMERA 147 

CHAPTER  VII. 

PROCESSES. 

THE  DRY  COLLODION  PROCESS — EMPLOYMENT  OF  ALBUMEN,  HONEY, 
AND  TANNIN — WAXED  PAPER  PROCESS— PERMANENT  PHOTO' 
GRAPHY  BY  THE  CARBON  PROCESS — METHODS  OF  POITEVIN, 
SWAN,     ETC .  .  •  .     153 

CHAPTER   VIII. 

PROBLEMS    TO    BE   SOLVED. 

THE  FIXING  OF  COLOURS— A  MYSTIFICATION — EDMOND  BECQUE- 
REL'S  experiments— ATTEMPTS  OF  NIEPCE  DE  SAINT-VICTOR 
AND   POITEVIN— PHOTOGRAPHIC   PRINTING  ....    169 


CONTENTS.  IX 


PART    III. 

THE  APPLICATIONS   OF  PHOTOGRAPHY. 


CHAPTER   I. 

HELIOGRAPHY. 

PAGE 

THE  DAGUERREOTYPE  PLATE  TRANSFORMED  INTO  AN  ENGRAVED 
PLATE — D0NN6 — FIZEAU — THE  PHOTOGRAPHIC  ENGRAVING  OF 
NIEPCE  DE  SAINT-VICTOR — PHOTO-LITHOGRAPHY  AND  HELIO- 
GRAPHY INVENTED  BY  A.  POITEVIN — PROCESSES  OF  BALDUS, 
GARNIER.  ETC. — THE  ALBERTYPE — OBERNETTER'S  PROCESS — 
MODERN    HELIOGRAPHY 1/9 

CHAPTER   II. 

PHOTOGLYPTY    (THE   WOODBURY    PROCESS). 

WOODBURY  —  IMPRESSION  OF  A  GELATINISED  PLATE  INTO  A 
BLOCK  OF  METAL— WORKING  OF  PHOTOGLYPTIC  METHODS  IN 
PARIS — DESCRIPTION  OF  MESSRS.  GOUPIL'S  ESTABLISHMENT — M. 
LEMERCIER I99 

CHAPTER  III. 

PHOTOSCULPTURE. 

AN  UNEXPECTED  DISCOVERY — PHOTOGRAPHY  APPLIED  TO  SCULP- 
TURE— WILLEME'S  process  IN  1861 — DESCRIPTION  OF  PHOTO- 
SCULPTURE  208 

CHAPTER   IV. 

PHOTOGRAPHIC   ENAMELS. 

VITRIFICATION  OF  A  PHOTOGRAPH — CAMARSAC'S  PROCESS— JEWELRY 
ENAMEL  —  METHOD  OF  MAKING— POITEVIN'S  METHOD — PER- 
MANENT GLAZE   PHOTOGRAPHS 2I4 


X  CONTENTS. 


CHAPTER  V. 

PHOTOMICROGRAPHY. 

PAGE 

THE  TOY  MICROSCOPES  OF  THE  PARIS  INTERNATIONAL  EXHIBITIONS 
—450  DEPUTIES  IN  THE  SPACE  OF  A  PIN's  HEAD — ARRANGE- 
MENTS OF  PHOTOMICROGRAPHIC  APPARATUS — THE  NATURAL 
SCIENCES  AND  PHOTOMICROGRAPHY  —  RESOU^RCES  BORROWED 
FROM    THE   HELIOGRAPH 220 

CHAPTER   VI. 

MICROSCOPIC   DESPATCHES   DURING  THE   SIEGE  OF    PARIS. 

APPLICATION  OF  MICROSCOPIC  PHOTOGRAPHY  TO  THE  ART  OF  WAR 
—THREE  MILLION  PRINTED  LETTERS  OF  THE  ALPHABET  ON 
THE  TAIL  OF  A  PIGEON — ENLARGEMENT  OF  THE  DESPATCHES 
— THEIR   CONVEYANCE   BY    CARRIER-PIGEONS       ....     235 

CHAPTER  VH. 

ASTRONOMICAL    PHOTOGRAPHY. 

CELESTIAL  PHOTOGRAPHY — DIFFICULTIES  OF  ASTRONOMICAL  PHO- 
TOGRAPHIC OPERATIONS— MESSRS.  WARREN  DE  LA  RUE,  RUTH- 
ERFURD,  GRUBB,  ETC.  —THE  LUNAR  MOUNTAINS — THE  SPOTS  ON 
THE  SUN,  ETC.  —  IMPORTANCE  OF  PHOTOGRAPHIC  DOCUMENTS 
FOR   THE    HISTORY    OF   THE    HEAVENS  .  •         ,    .  .  .    249 

CHAPTER  Vni. 

PHOTOGRAPHIC    REGISTERING    INSTRUMENTS. 

IMPORTANCE  OF  REGISTERING  INSTRUMENTS — PHOTOGRAPHIC  BARO- 
METERS AND  THERMOMETERS — THE  REGISTRATION  OF  THE 
VIBRATIONS  OF  THE  MAGNETIC  NEEDLE— RONALD'S  PHOTO- 
ELECTROGRAPH — PHOTOGRAPHIC  PHOTOMETRY — PHOTOGRAPHY 
OF  COLUMNS  OF  WATER  RAISED  BY  A  TORPEDO — OF  THE 
PHENOMENA  OF  THE  INTERFERENCE  OF  THE  RAYS  OF  THE 
SPECTRUM 268 

CHAPTER   IX. 

THE   STEREOSCOPE. 

A  FEW  WORDS  ON  STEREOSCOPIC  VISION— MEANS  OF  MAKING  PHO- 
TOGRAPHIC  PRINTS  APPEAR  IN  RELIEF— WHEATSTONE'S  STEREO- 


CONTENtS.  xi 


PAGE 
SCOPE — MONOSTEREOSCOPE — HOW   STEREOSCOPIC    PHOTOGRAPHS 
ARE   PRODUCED 287 

CHAPTER   X. 

PHOTOGRAPHY   AND   ART, 

IS  PHOTOGRAPHY  ART? — ITS  USES  IN  RELATION  TO  PAINTING, 
REPRODUCTION  OF  ENGRAVINGS,  VOYAGES  OF  DISCOVERY  — 
PHOTOGRAPHY  BY  THE  MAGNESIUM  LIGHT — PHOTOGRAPHIC 
PORTRAITS   CONSIDERED   AS   HISTORICAL  DOCUMENTS  .  *        .    297 

CHAPTER  XI. 

THE    FUTURE   OF    PHOTOGRAPHY. 

LAND-SURVEYING — THE  ART  OF  WAR— WORKS  OF  ART — CRIMINALS 
AND  JUDICIAL  PHOTOGRAPHY — THE  MIRACLES  OF  INSTANTA- 
NEOUS   PHOTOGRAPHY 306 


APPENDIX. 


PANORAMIC  PHOTOGRAPHY  -PANORAMIC  CAMERA— THE  HELIOTYPE 
PROCESS — THE  PHOTO-TINT  PROCESS — EPITOME  OF  THE  WET 
COLLODION  PROCESS  AND  USEFUL  FORMULAE— SENSITISING  BATH 
—  DARK  ROOM  OPERATIONS— FIXING — POSITIVE  SILVER-PRINT- 
ING FORMULA— SIMPLE  METHOD  OF  PREPARING  DRY  PLATES 
— ENGLISH    AND    FRENCH   WEIGHTS    AND    MEASURES   .  .  -313 


INDEX 323 

ADVERTISEMENTS  relating  to  photography     .  327  et  seq. 


LIST    OF    ILLUSTRATIONS. 


FULL-PAGE  ENGRAVINGS. 

PORTRAIT    FROM    LIFE   BY    THE    PHOTO-TINT    PROCESS           .  Frontispiece 

PROFESSOR    CHARLES'S    EXPERIMENT        ....  To  face  p.  ID 

DAGUERRE'S   DIORAMA ,,13 

THE   DARK    ROOM .           ,,90 

SPECIMEN  OF  A  HELIOGRAPHIC  ENGRAVING.  (After  a  Draw- 
ing by  Gustave  Dore ) .          .  .         .         .         .         ,  , ,      1 96 

THE   SOLDIER    OF    MARATHON ,,197 

FACSIMILE    OF   THE    PHOTOGRAPH  OF  A    FLEA,    OBTAINED  BY 

THE   PHOTOMICROGRAPHIC    APPARATUS  .  .  .  ,,       23O 

ENLARGING  MICROSCOPICAL  DESPATCHES  DURING  THE   SIEGE 

OF   PARIS ,,241 

DEPARTURE      OF      CARRIER-PIGEONS      FROM     THE       CHAMPS- 

^LYSfiES,    PARIS ,,       247 

SALLERON's  photographic  barometer  and  THERMO- 
METER     ,,       275 

photo-electrographic  instrument  at  kew  observa- 
tory, FOR  REGISTERING  THE  STATE  AND  VARIATIONS 
OF  THE  ELECTRICITY  OF   THE  AIR       ....  ,,       277 

IOCKYER'S  APPARATUS    FOR   ANALYSING   AN   ALLOY   OF  GOLD 

AND   SILVER    BY  THE    PHOTOGRAPHY    OF    ITS    SPECTRUM  ,,       285 


XIV  LIST   OF   ILLUSTRATIONS. 

APPARATUS     FOR     OBTAINING     THE     TWO      PROOFS    OF     THE 

STEREOSCOPE To  face  p.  295 

FAC-SIMILE  OF  A   STEREOSCOPIC   PHOTOGRAPH  .  .  .  ,,         296 

PHOTOGRAPHY  AND   EXPLORATION ,,         302 

THE   POLfiMOSCOPE ,,         307 


WOODCUTS    IN    TEXT. 

PAGE 

THE   DARK   ROOM 2 

THE    IMAGE   OF   THE   SUN    FORMED   ON    THE    SHADOW   OF   A   TREE  3 

JOSEPH    NIEPCE '44 

DAGUERRE 59 

DAGUERREOTYPE   POLISHER 6$ 

MERCURIAL   DEVELOPING    BOX 66 

GILDING   THE   DAGUERREOTYPE   PLATE 69 

PHOTOGRAPHIC    BELLOWS    CAMERA 94 

THE   LENS,    WITH    ITS    RACKWORK   AND   CAP              ....  96 

SIMPLE    PHOTOGRAPHIC   APPARATUS 97 

THE   CAMERA    STAND 99 

THE    DARK    SLIDE IOC 

TWIN-LENS    CAMERA,   SHOWING    DARK    SLIDE    AND    DIAPHRAGMS      .  lOI 

THE    HEAD-REST IO3 

PLATE-HOLDER I06 

COATING   THE   PLATE.       FIRST   POSITION    OF   THE   HANDS     .           .  IO9 

SECOND    POSITION    OF   THE   HANDS IO9 

SENSITISING   TRAY .  Ill 

SILVER   HOOK   FOR   RAISING   AND   LOWERING   THE   PLATE         .            .  Ill 


LIST   OF   ILLUSTRATIONS.  XV 

PAGE 

GLASS   BATH    IN    CASE   WITH    GLASS   DIPPER  .  .  .  .  112 

WASHING   THE   DEVELOPED    IMAGE II4 

RACK    FOR   DRYING   PLA'.'ES II 8 

PLATE   BOX     .  .  ._ 119 

fHE    PRINTING    FRAME 124 

PRINTING    FRAMES   EXPOSED   TO   THE   LIGHT  .  .  .  .  I26 

SIMPLE   PRINTING   FRAME I26 

THE    ROLLING    PRESS 1 29 

PORTABLE    PHOTOGRAPHIC    APPARATUS I36 

PHOTOGRAPHIC    CARICATURE I44 

MONCKHOVEN'S   ENLARGING    CAMERA I49 

LIEBERT'S   ENLARGING   APPARATUS I50 

THE   SOLDIER   OF   MARATHON 1 97 

PHOTOGLYPTIC    PRESS 202 

TURN-TABLE   REQUIRED    FOR   TAKING    PHOTOGLYPTIC    PROOFS      .  203 

PHOTO-ENAMEL   BROOCH 217 

DUSTING-SIEVE 2X8 

TOY    MICROSCOPE   OF   THE    EXHIBITION    OF    1 867      ....  220 

MICROSCOPE   FITTED    TO   THE   CAMERA  .....  224 

ARRANGEMENT   OF    THE    PHOTOMICROGRAPHIC    APPARATUS     ON    A 

BENCH 226 

VERTICAL    MICROSCOPE   ADAPTED   TO   THE   CAMERA    FOR    PHOTOMI- 
CROGRAPHY    228 

PHOTOMICROGRAPHIC   APPARATUS   FOR    ARTIFICIAL   LIGHT      .  .  229 

FACSIMILE   OF  THE   PHOTOGRAPH   OF   SECTIONS   OF   IHE    STEM    OF 

A   CANE 230 

SECTION   OF   THE  WOOD   OF   A   FIR-TREE 23O 

GROUP   OF   DIATOMS 23I 


XVI  LIST   OF   ILLUSTRATIONS. 

TAGE 

SECTION   OF  THE   FIN   OF   A  WHALE 232 

EPIDERMIS   OF   A   CATERPILLAR 233 

CARRIER-PIGEON   WITH   PHOTOGRAPHIC    DESPATCHES             .            .  236 

QUILL     CONTAINING     MICROSCOPIC    DESPATCHES     FASTENED   TO   A 

TAIL   FEATHER   OF   CARRIER-PIGEON 237 

STAMPS,  SHOWING   WHEN    DESPATCHES  WERE   FORWARDED    OR    RE- 
CEIVED, PRINTED   ON   THE   WING 238 

FACSIMILE  OF  A   MICROSCOPIC    DESPATCH    DURING   THE  SIEGE   OF 

PARIS 239 

CHINESE  WHISTLES   ATTACHED   TO   CARRIER-PIGEONS     .            .            .  245 

LUNAR   MOUNTAINS.     AFTER  A   PHOTOGRAPH    BY   MR.  WARREN    DE 

LA   RUE 254 

UNDULATING    LINES    TRACED  ON    THE   CARRIER   OF   THE    ELECTRO- 
GRAPH     ....  278 

BREWSTER'S    STEREOSCOPE 29O 

HEIMHOLTZ'S    STEREOSCOPE 29 1 

MONO-STEREOSCOPIC   PRINT 292 

FEVRIER'S   pillar  STEREOSCOPE 293 

PLATE    FOR     SUPPORTING    THE    CAMERA   WHEN    TAKING   STEREO- 
SCOPIC  VIEW 295 

PHOTOGRAPHY    BY   THE    MAGNESIUM    LIGHT    IN    THE    CATACOMBS  303 

PANORAMIC   CAMERA 314 


PART    I. 

THE  HISTORY  OF  PHOTOGRAPHY. 


CHAPTER   I. 

THE   ORIGIN    OF   PHOTOGRAPHY. 

J.  B.  PORTA  AND  THE  DARK  ROOM — FABRICIUS  THE  ALCHEMIST  — 
LUNA  CORNEA — PROFESSOR  CHARLES'  SILHOUETTES — WEDGWOOD, 
HUMPHRY   DAVY,    AND  JAMES   WATT. 

The  discovery  of  photography  ranks  amongst  the  most 
wonderful  applications  of  modern  science ;  we  owe  it 
almost  solely  to  the  genius  of  Niepce  and  Daguerre. 
We  shall  mention  the  obstacles  which  these  great  minds 
had  to  overcome  before  solving  a  problem  which  had  long 
been  looked  upon  as  Utopian  ;  we  shall  thus  see  with 
what  perseverance  the  inventor  must  arm  himself  to 
attain  his  ends.  But  before  relating  facts  we  think  it 
would  be  useful  to  look  a  little  farther  into  the  past  to 
seek  their  causes.  Nothing  is  more  instructive  than  the 
impartial  history  of  great  discoveries  ;  it  shows  us  how 
slow  is  the  march  of  progress,  and  how  many  beacons 

B 


THE   HISTORY   OF   PHOTOGRAPHY. 


must  shine  along  the  course  of  centuries  to  guide  the 
inventor  into  the  region  of  the  unknown.  First  appears  a 
man  who  sows  the  germ,  others  follow  and  cultivate  it, 
up  to  the  time  when  some  genius  fertilises  and  renders  it 
fruitful. 

The  germ  of  photography  is  the  dark  room  (or 
camera  obscura),  discovered  in  the  second  half  of  the 
sixteenth  century  by  J.  B.  Porta,  a  clever  Italian  philo- 

Fig.  I. 


THE   DARK    ROOM. 


sopher.  The  process  which  the  illustrious  Neapolitan 
employed  was  most  simple.  He  made  an  aperture, 
hardly  large  enough  to  admit  the  little  finger,  in  the 
shutter  of  a  window  so  perfectly  closed  as  entirely  to 
exclude  light.  The  rays  of  light  penetrating  through 
the  circular  hole  into  the  dark  room  were  projected  on 
to  a  white  screen,  on  which  they  depicted  the  reversed 


THE   ORIGIN    OF   PHOTOGRAPHY. 


image  of  exterior  objects.     (Fig.   i.)     The  simple  ob- 
servation of  Nature  might  have  led  at  once  to  this  dis- 

Fig    2. 


THE    IMAGE  OF   THE  SUN   FORMED   ON    THE   SHADOW   OF   A   TREE. 

covery.     The  foliage  of  trees  does  not  entirely  intercept 
the   sun's    light,  it  often    allows  rays   of  light  to  pass 


THE  HISTORY  OF   PHOTOGRAPHY. 


through  the  spaces  which  exist  between  the  leaves,  and 
the  images  of  the  ruler  of  the  day  appear  as  luminous 
discs  in  the  midst  of  the  well-defined  shadows  on  the 
ground.  (Fig.  2.)  It  is  easy  to  reproduce  this  pheno- 
menon by  passing  the  light  of  a  candle  across  a  small 
orifice,  and  projecting  it  on  to  a  screen,  on  which  a  re- 
versed imiage  of  the  flame  will  be  seen. 

Porta,  in  his  treatise  on  '  Natural  Magic,'  goes  into 
raptures,  and  excusably,  over  his  discovery,  of  which  he 
seems  to  have  foreseen  all  the  future  importance  ;  he 
describes  it  with  irrepressible  admiration,  and  after 
describing  it,  exclaims  with  enthusiasm,  'We  can  dis- 
cover Nature's  greatest  secrets  ! ' 

And  truly,  indeed,  must  those  have  wondered  whom 
Porta  initiated  into  the  mysteries  of  his  dark  room  ! 
With  what  bewilderment  would  they  not  contemplate 
this  sharp,  lifelike,  and  delicate  picture,  drawn  by  the 
light  on  a  screen,  which  was  thus  transformed  into  a 
faithful  mirror ! 

Soon,  by  means  of  a  convex  lens,  fixed  in  the  aper- 
ture in  his  shutter,  and  by  the  aid  of  a  glass  mirror 
which  reversed  the  image.  Porta  was  enabled  to  contem- 
plate the  representation  of  exterior  objects  no  longer 
reversed,  but  in  their  natural  positions.  Porta  lost  no 
time  in  recommending  the  use  of  the  dark  room  to  all 


THE   ORIGIN   OF   PHOTOGRAPHY.  5 

painters  desirous  of  obtaining  exact  and  minute  delinea- 
tion,  and  shortly  afterwards  Canaletto  profited  by  his 
advice  and  employed  the  invention  for  taking  his  ad 
mirable  views  of  Venice. 

What  would  the  Neapolitan  philosopher  and  the 
Venetian  painter  have  said  had  they  been  told  that  this 
image  of  the  dark  room  would  one  day  draw  itself,  not 
merely  fugitively,  but  that  it  would  print  itself  on  a  glass 
moistened  with  chemical  agents,  that  it  would  transform 
itself  into  a  durable  picture,  only  to  be  compared  for 
exactness  to  the  reflection  of  a  mirror  ?  This  wonder 
was,  indeed,  to  be  accomplished  unknown  to  Porta ;  but 
his  work  was  not  in  itself  sufficient  to  conduct  science  to 
such  a  result,  numerous  labourers  had  also  to  add  their 
stone  to  the  edifice. 

To  find  another  of  the  original  principles  of  photo- 
graphy we  must  quit  Naples  and  transport  ourselves  to 
France,  and  to  a  little  earlier  epoch,  when  alchemy 
seemed  to  have  attained  its  utmost  development.  It  was 
in  the  middle  of  the  sixteenth  century  that  the  action 
of  light  on  the  nitrates  of  silver  was  accidentally  dis- 
covered by  an  alchemist. 

The  few  isolated  observations  which  had  been  made 
up  to  this  time  were  very  incomplete  and  little  known. 
The  Greeks  knew  that  the  opal  and  amethyst  lost  their 


THE   HISTORY   OF   PHOTOGRAPHY. 


brilliance  if  exposed  to  the  lengthened  action  of  the  solar 
rays.  'Vitruvius  had  noticed  that  the  sun  altered  and 
changed  certain  colours  used  in  painting,  and  therefore 
always  placed  his  pictures  in  rooms  with  a  northern 
aspect.  But  such  observations  as  these  can  hardly  be 
considered  as  the  results  of  scientific  study. 

The  alchemists  have  often  been  the  subject  of 
calumny.  Though  it  is  true  that  amongst  the  adepts 
in  the  ^ Black  Art'  there  were  numerous  charlatans  and 
quacks,  it  must  not  be  forgotten  that  a  large  number  of 
the  philosophers  of  the  middle  ages,  men  of  indefatigable 
research,  were  possessed  with  a  real  love  of  their  art ; 
which  they  cultivated  if  not  with  method  at  least  with 
invincible  perseverance.  It  was  one  of  these  laborious 
workers  who  first'  produced  chloride  of  silver,  and 
recognised  the  important  property  possessed  by  this 
substance  of  becoming  black  under  the  action  of  light. 

This  disciple  of  Hermes  was  named  Fabricius.  One 
fine  day,  buried  probably  in  the  confusion  of  his  labo- 
ratory, after  having  conjured  up  the  devil  and  all  the 
imps  of  darkness,  after  having  in  vain  ransacked  the 
books  of  magic,  which  swarmed  in  the  middle  ages,  for 
the  formula  of  that  panacea  which  was  to  prolong  life, 
cure  all  ills,  and  transmute  the  metals,  he  threw  some 
sea  salt  into  a  solution  of  nitrate  of  silver  and  obtained 


THE   ORIGIN    OF    PHOTOGRAPHY. 


a  precipitate  (chloride  of  silver)  to  which  the  alchemists 
of  those  times  gave  the  name  of  '  Luna  cornea,'  or  'horn- 
silver,'  He  collected  it,  and  what  w^as  his  astonishment 
when  he  perceived  that  this  substance,  as  white  as  milk, 
became  suddenly  black  as  soon  as  a  ray  of  sunlight  fell 
on  its  surface  ! 

Fabricius  continued  to  study  this  remarkable  pro- 
perty, and  in  his  '  Book  of  the  Metals,'  published  in  1556, 
he  relates  that  the  image  projected  by  a  glass  lens  on  to 
a  surface  of  '  Luna  cornea '  imprinted  itself  in  black  and 
grey,  according  as  the  parts  were  completely  illuminated, 
or  touched  only  by  diffused  light.  But  here  the  alche- 
mist stopped  ;  this  fact,  so  full  of  significance,  remained 
a  dead  letter  in  his  hands.  The  science  of  those  times, 
powerless  through  want  of  method,  ignored  the  art  of 
inferring  from  observation,  and  of  confirming  by  expe- 
riments the  deductions  thus  obtained.  The  chemists  of 
this  epoch  could  not  see  because  their  eyes  had  not  been 
trained  to  look  ;  they  let  the  fact  escape  and  pursued 
the  fancy  ;  like  the  dog  in  the  fable,  they  abandoned 
the  substance  to  grasp  the  shadow.  What  did  it  signify 
to  Brandt  if  he  discovered  phosphorus,  to  Basile  Valentin 
if  antimony  issued  from  his  crucibles,  to  Albert  the 
Great  if  nitric  acid  was  distilled  in  his  retort.'*  all 
this,   to   these  preoccupied   minds,  was  not  the  philoso- 


8  THE   HISTORY   OF   PHOTOGRAPHY. 

pher's  stone.  They  did  not  deem  it  worth  while 
to  stop  at  such  inventions.  They  passed  on,  and  con- 
^demned  themselves  to  wander  in  labyrinths  without 
issues,  they  travelled  through  life  as  if  impelled  by  fate 
towards  a  chimerical  goal,  which  they  could  never  reach. 
They  groped  along  regardless  of  the  great  opportunities 
with  which  chance  strewed  their  path,  and  did  not  even 
stoop  to  lift  the  gems  which  good  fortune  threw  in  their 
way  ! 

Fabricius  missed  the  principle  of  one  of  the  most 
astonishing  arts  of  modern  times.  Why  was  he  not 
struck  with  some  sublime  presentiment,  of  which  genius 
seems  to  have  the  secret }  why  was  he  not  suddenly  seized 
with  one  of  those  fortuitous  inspirations  which  seem  to 
be  the  birthright  of  true  genius  .? 

It  was  thus  that,  in  1760,  a  fantastical  writer, 
though  not  a  Fabricius,  nevertheless  divined  photo- 
graphy. If  Cyrano  de  Bergerac,  born  two  centuries 
before  balloons,  may  be  considered  as  an  aeronaut, 
Tiphaine  de  la  Roche  may  be  equally  regarded  as  a 
photographer.  This  Tiphaine  was  a  native  of  Nor- 
mandy and  a  great  lover  of  eccentricities  ;  he  has  left 
us  a  whimsical  book  in  which  there  is  much  that  is 
astonishing,  buried  though  it  is  in  an  indescribable 
medley  of  nonsense.      In    one  of  the  chapters  of  this 


THE  ORIGIN   OF  PHOTOGRAPHY.  9 

curious  old  book  he  relates  how  he  was  caught  up  in  a 
hurricane  and  deposited  in  the  domain  of  the  genii, 
who  initiated  him  in  the  secrets  of  Nature.  'You 
know,*  said  one  of  them  to  Tiphaine,  *  that  rays  of  light 
reflected  from  different  bodies  form  pictures,  paint 
the  image  reflected  on  all  polished  surfaces — for  example, 
on  the  retina  of  the  eye,  on  water,  and  on.  glass.  The 
spirits  have  sought  to  fix  these  fleeting  images ;  ^  they 
have  made  a  subtle  matter  by  means  of  which  a  picture 
is  formed  in  the  twinkling  of  an  eye.  They  coat  a  piece 
of  canvas  with  this  matter,  and  place  it  in  front  of  the 
object  to  be  taken.  The  first  effect  of  this  cloth  is 
similar  to  that  of  the  mirror,  but  by  means  of  its  vis- 
cous nature  the  prepared  canvas,  as  is  not  the  case 
with  the  mirror,  retains  a  facsimile  of  the  image.  The 
mirror  represents  images  faithfully,  but  retains  none  ;  our 
canvas  reflects  them  no  less  faithfully,  but  retains  them 
all.  This  impression  of  the  image  is  instantaneous. 
The  canvas  is  removed   and  deposited  in  a  dark  place. 


*  This  recalls  a  Chinese  tradition  which  accords  to  the  sun  the  power 
of  photographing  a  landscape  on  a  sheet  of  ice.  An  ancient  sage,  it  is 
said,  discovered  a  picture  of  the  trees  and  shrubs  on  the  banks  of  a  stream 
engraven  on  its  frozen  surface.  It  seemed  as  if  the  reflected  image  were 
caught  and  frozen  on  the  ice.  But  this  early  example  of  photography, 
if  it  ever  existed  at  all,  may  have  been  produced  by  a  powerful  gleam 
of  the  hot  sun  of  North  China  tracing  the  outlines  of  shadows  thrown 
across  a  dark  surface  of  ice  thinly  covered  with  snow. — Ed. 


10  THE    HISTORY   OF    PHOTOGRAPHY. 

An  hour  after  the  impression  is  dry,  and  you  have  a 
picture  the  more  precious  in  that  no  art  can  imitate  its 
truthfulness.' 

In  writing  these  truly  prophetic  lines,  had  Roche  no 
knowledge  of  the  book  of  F'abricius,  or  rather  had  he 
not  himself  experimented  .with  Porta's  dark  room,  in  sup- 
posing, as  though  in  a  dream,  that  the  fleeting  reflection 
had  been  fixed  for  ever  ?  We  cannot  say.  But  however 
that  may  be,  to  find  really  serious  and  scientific  studies 
we  must  come  down  to  the  end  of  the  eighteenth  cen- 
tury— to  that  period,  the  most  surprising  perhaps  in  the 
history  of  progress,  when  the  gloom  of  the  past  dispersed, 
when  light  appeared,  when  the  savant  rubbed  his  eyes 
and  for  the  first  time  looked  around  him. 

In  1777,  Scheele,  the  great  Swedish  chemist,  dis- 
covered that  chloride  of  silver  is  much  more  sensitive  to 
blue  and  violet  rays  than  to  those  of  a  green  and  red 
colour.  About  the  year  1780,  Professor  Charles,  the 
inventor  of  the  hydrogen  gas  balloon,  made  the  first 
use  of  the  dark  room  for  attempting  to  produce  rudi- 
mentary photographs.  He  exhibited  to  the  numerous 
and  attentive  audience  at  his  course  of  lectures  on 
natural  science  a  curious,  and  at  that  time  even 
wonderful  experiment.  By  means  of  a  strong  solar  ray, 
he  projected  a  shadow  of  the  head  of  one  of  his  pupils 


THE   ORIGIN   OF   PHOTOGRAPHV.  II 

on  to  a  sheet  of  white  paper  which  had  previously  been 
soaked  in  a  solution  of  chloride  of  silver.  Under  the 
influence  of  the  light  it  was  not  long  in  becoming  black 
in  the  parts  exposed,  remaining  white  on  that  portion  of 
the  sheet  which  had  been  shaded,  and  thus  giving  a 
faithful  silhouette  of  the  person's  head  in  white  on  a 
black  ground.  (Fig.  3.^)  This  sheet  of  paper,  which 
seemed  as  though  endowed  with  magical  properties,  was 
passed  from  hand  to  hand  ;  but  soon  the  light  acting  on 
the  silhouette  till  then  white,  blackened  it  like  the  ground, 
and  the  profile  disappeared  little  by  little  as  though 
blotted  out  with  ink. 

Professor  Charles  also  reproduced,  roughly,  it  is  true, 
some  engravings  which  he  placed  on  a  sensitised  paper. 
The  details  of  this  experiment  are,  however,  for  the 
most  part  wanting  in  the  historical  documents  relating 
to  his  works. 

Wedgwood,  a  clever  English  scientist,  made  a  similar 
experiment  to  Professor  Charles' ;  he  projected  the  image 


J  Our  illustration  of  this  curious  experiment  of  the  celebrated  chemist 
is  based  on  the  rather  vague  and  incomplete  accounts  which  were  given  of 
it  at  the  time  of  its  exhibition  by  Professor  Charles.  We  suppose  in  our 
engraving  that  the  experiment  is  just  commencing  ;  the  silhouette  of  the 
person  is  in  black  ;  a  few  moments  later,  the  part  of  the  paper  represented 
as  white  will  become  black,  and,  when  the  person  retires,  it  is  his  shadow 
seen  in  black,  which  appears  in  white  because  the  light  could  not  affect 
this  part  of  the  silvered  paper. 


12  THE   HISTORY   OF   PHOTOGRAPHY. 

of  the  dark  room  on  to  a  sheet  of  paper  similarly  sen- 
sitised, and  obtained  a  rough  picture,  which  could  only 
be  preserved  in  the  dark.  In  1802  Wedgwood  and  Sir 
Humphry  Davy  published  a  remarkable  treatise  on  the 
reproduction  of  objects  by  light.' 

James  Watt,  the  celebrated  inventor  of  the  steam 
engine,  also  studied  this  singular  phenomenon ;  and  the 
problem  of  fixing  the  image  of  the  camera  occupied  his 
great  mind  for  some  time ;  but  the  results  he  obtained 
were  doubtless  insignificant,  for  he  does  not  refer  to 
them  at  all  in  his  writings.  It  was  much  the  same  with 
the  great  English  chemist,  Humphry  Davy,  who  has 
left  us  a  few  lines  on  the  subject  of  Wedgwood's  experi- 
ment. 

*  All  that  is  wanting,'  said  he,  '  is  a  means  of  pre- 
venting the  lights  of  the  picture  from  being  afterwards 
coloured  by  daylight ;  if  this  result  is  arrived  at,  the 
process  would  become  as  useful  as  it  is  simple.  Up  to 
the  present  time  it  is  necessary  to  keep  the  copy  of  the 
picture  in  the  dark,  and  it  can  only  be  examined  in  the 
shade,  and  then  but  for  a  short  time.       I  have  tried  in 

*  This  method  was  also  employed  to  delineate  profiles,  or  shadows  of 
figures,  the  woody  fibres  of  leaves,  wings  of  insects,  &c.  Chloride  of  silver 
in  a  wet  state  was  found  to  be  more  susceptible  to  the  influence  of  light 
than  nitrate  of  silver.  Pictures  produced  at  this  time  could  not  be 
fixed.  — Ed. 


THE  ORIGIN   OF   PHOTOGRAPHY.  1 3 

vain  every  possible  method  of  preventing  the  uncoloured 
parts  from  being  affected  by  the  light.  As  for  the 
images  of  the  dark  room,  they  were  doubtless  not  suffi- 
ciently illuminated  to  enable  me  to  obtain  a  visible 
picture  with  the  nitrate  of  silver.  It  is  that,  nevertheless, 
which  is  the  great  point  of  interest  in  these  experiments. 
But  all  attempts  have  been  fruitless.' 

The  problem  which  Davy  thus  clearly  describes,  and 
which  neither  Charles,  Wedgwood,  Watt,  nor  himself 
could  solve,  was  destined  to  be  overcome  by  two  French- 
men, whose  names  ought  to  be  reckoned  amongst  the 
glories  of  the  national  genius. 


14  THE   HISTORY   OF   PHOTOrxRAPHY. 


CHAPTER- II. 

DAGUERRE. 

DEGOTTI  THE  SCENE-PAINTER— EARLY  LIFE  OF  DAGUERRE— INVEN- 
TION OF  THE  DIORAMA  —  THE  CAMERA  OR  DARK  ROOM  — 
CHEVALIER  THE  OPTICIAN — THE  HISTORY  OF  AN  UNKNOWN— FIRST 
LETTER    OF    DAGUERRE   TO    NIEPCE. 

At  the  commencement  of  the  present  century  there 
was  at  Paris  a  scene-painter  of  the  name  of  Degotti,  who 
painted  the  finest  scenes  of  the  Grand  Opera.  At  his 
celebrated  studio  this  master  produced  truly  wonderful 
pictures.  He  taught  numerous  pupils  who  by  their 
natural  disposition  were  drawn  more  towards  inde- 
pendence of  colour  and  freedom  of  pencil  than  towards 
the  school  of  the  Academy.  One  of  the  followers  of 
Degotti  soon  signalised  himself  by  his  rare  talents  ; 
he  attacked  the  canvas  with  the  ardour  of  an  artist 
thoroughly  imbued  with  the  grand  effects  of  paint- 
ing. The  name  of  this  promising  debutant  was 
Daguerre. 

Daguerre  was  born  in  1787  at  Cormeilles  near  Paris. 


DAGUERRE.  1 5 


In  the  midst  of  the  political  paroxysms  and  cataclysms 
of  the  great  Revolution  his  childhood  was  singularly  neg- 
lected. Arrived  at  a  suitable  age,  his  parents  allowed 
him  to  make  his  own  choice  of  a  profession.  The  youth- 
ful Daguerre  gladly  chose  the  career  of  an  artist.  From 
his  tenderest  childhood,  as  soon,  indeed,  as  he  could 
hold  it  between  his  fingers,  he  had  exhibited  a  wonder- 
ful facility  with  the  pencil.  He  excelled  in  rendering 
with  fidelity  the  most  difficult  effects  of  the  boldest  per- 
spective, he  studied  especially  scenic  effect,  and  he  thus 
soon  found  himself  at  home  in  Degotti's  studio,  where 
he  was  not  long  in  equalling  and  then  excelling  the 
talent  of  his  master. 

Not  only  was  young  Daguerre  a  genius  at  landscape 
scene-painting,  the  specialite  of  scene-painters,  but  he 
could  readily  solve  the  mechanical  problems  relating  to 
the  mysteries  '  behind  the  scenes.'  such  as  fixing,  shift- 
ing, &c.  He  substituted  for  the  movable  frames  of  the 
side  scenes  large  canvas  backgrounds  on  which  a  whole 
vast  landscape  or  an  entire  panorama  could  be  repre^ 
sented.  But  not  content  with  producing  a  masterly 
picture,  he  conceived  the  idea  of  giving  it  a  value  until 
then  unknown,  by  having  recourse  to  the  untried  re- 
sources of  powerful  illumination.  His  first  attempts 
met  with  unexpected  success.  The  unknown  artist  of 
yesterday  had  become  the  pet  of  the  Parisian  populace. 


1 6  THE   HISTORY   OF   PHOTOGRAPHY. 

At  the  Opera,  at  the  Ambigu  Comique,  in  *  The 
Dream,'  in  '  The  Wonderful  Lamp,'  in  *  The  Vampire,' 
the  scenes  of  the  new  painter  had  an  immense  success 
every  night.  The  papers  and  theatrical  journals  spoke 
of  nothing  but  the  effects  of  the  rising  moon  and  the 
setting  sun  ;  and  the  name  of  Daguerre  flew  from  mouth 
to  mouth,  carried  by  the  eclat  so  resounding  in  Paris,  es- 
pecially when  it  celebrates  anything  which  affects  the 
pleasures  of  the  public.  ' 

But  Daguerre  did  not  rest  content  with  this  ;  he 
aimed  at  a  more  lasting  fame  ;  his  success  far  from  ele- 
vating served  only  to  stimulate  him  :  he  dreamt  of  new 
triumphs,  and  in  spite  of  the  dissipations  of  Parisian  life, 
he  never  forgot  that  work  and  perseverance  are  the  two 
levers  capable  of  raising  great  results.  He  had  doubt- 
less to  struggle  with  the  enticements  of  pleasure,  for  his 
temperament  was  ardent  and  his  spirits  lively  and  imagi- 
native. Educated  in  the  midst  of  art  studios  and 
theatres,  and  naturally  gay  and  light-hearted,  he  was  a 
very  *  gamin  de  Paris,'  as  several  well-authenticated  facts 
in  his  biography  sufficiently  show.  Unusually  agile,  he 
was  at  home  in  all  manly  sports  ;  he  excelled  in  throwing 
summersaults  and  feats  of  strength,  and  he  would  some- 
times at  social  gatherings  amuse  his  friends  by  walking 
on  his  hands  with  his  legs  in  the  air.     It  is  even  said 


DAGUERRE.  1/ 


that  he  loved  to  appear  incognito  on  the  stage  at  the 
Opera,  where  his  paintings  excited  universal  admiration. 
He  donned  the  costume  of  the  ballet  corps  and  figured 
in  chorographical  acts,  amused  at  the  applause  of  the 
public,  which  had  not  the  least  idea  that  under  the  dress 
of  this  dancer  was  hidden  an  inventor  of  genius.  But 
these  somewhat  puerile  amusements  did  not  hinder 
Daguerre  from  working,  and  dreaming  of  success 
and  fame.  His  ingenious  and  inventive  mind,  once 
entered  upon  the  road  to  celebrity,  would  follow  it,  mark- 
ing each  of  his  steps  with  a  new  conquest ;  his  inven- 
tion of  the  Diorama  excited  universal  enthusiasm, 

July  I,  1822,  saw  crowds  of  people  streaming  towards 
a  new  establishment  on  the  Boulevard.  They  were  for 
the  first  time  going  to  see  a  spectacle  which  was  to  be  for 
many  years  an  object  of  general  admiration.  Daguerre 
had  entered  into  partnership  with  the  painter  Bouton, 
and  together  they  had  conceived  the  idea  of  imitating 
nature  by  means  of  immense  sheets  of  canvas,  the  sub- 
jects on  which  were  thrown  in  relief  by  a  powerful  and 
well-arranged  system  of  lighting. 

These  Dioramic  scenes  represented  views,  interiors, 
and  landscapes  with  wonderful  fidelity,  and  with  a  truly 
surprising  finish  in  execution.  But  that  which  especially 
excited  the  admiration  of  the  spectators  was  the  gradual 

C 


1 8  THE    HISTORY   OF   PHOTOGRAPHY. 

changing  of  the  scenes,  which  appeared,  so  to  speak,  to 
dissolve  into  one  another,  one  following  another  without 
appreciable  interruption.  All  Paris  wentto  see  Daguerre's 
Diorama,  and  applauded  the  beautiful  pictures  of  the 
Valley  of  Sarnen,  of  the  Tomb  of  Charles  X.  at  Holy- 
rood,  and  of  the  Basilica  of  St.  Peter.  The  effects  pro- 
duced by  the  dioramic  canvas  were  as  beautiful  from  an 
art  point  of  view  as  they  were  curious  as  changes  of 
scene. 

One  contemplated,  for  example,  the  Valley  of  Goldau, 
where  fir-trees  crowned  as  with  a  diadem  of  verdure  the 
cottages  of  a  humble  village  sleeping  on  the  borders  of  a 
peaceful  lake ;  then  suddenly  the  sky  became  gloomy, 
dark  threatening  clouds  appeared,  a  violent  concussion 
shook  the  mountain,  the  avalanche  descended,  impetuous, 
terrible,  it  rushed  on  the  village,  burying  it  in  ruins  ;  to 
the  peaceful  picture  of  but  a  moment  before,  had  suc- 
ceeded a  dreadful  scene  of  falling  and  crashing  rocks  in 
indescribable  confusion. 

We  are  at  the  present  day  acquainted  with  the 
secrets  of  the  Diorama,  which,  however,  our  space  will  not 
permit  us  to  describe  fully ;  but  it  played  such  an  im- 
portant part  in  the  life  of  Daguerre  that  we  cannot  pass 
it  by  entirely  in  silence.  The  accompanying  engraving 
shows  the  general  aspect  of  the  apparatus.     We  may 


DAGUERRE.  1 9 


add  that  the  canvas  was  painted  on  both  sides,  and  that 
as  the  light  was  thrown  on  the  front  or  back — that  is 
to  say,  reflected  or  transmitted — the  one  or  the  other 
picture  appeared,  and  thanks  to  this  ingenious  artifice 
the  spectator  admired  the  changes  of  scenes  so  rapid  and 
surprising. 

The  success  of  the  Diorama  did  not  content  Daguerre, 
and  a  still  more  brilliant  fortune  was  in  store  for  this 
active  and  ambitious  mind. 

In  executing  his  pictures,  Daguerre  constantly  em- 
ployed the  camera  obscura  (or  dark  room)  ;  he  en- 
deavoured to  reproduce  faithfully  the  lively  picture 
which  the  light  after  passing  through  the  crystal  of  a 
lens  traced  on  the  screen  at  the  back  of  his  camera,  but 
he  felt  that  his  art  was  powerless  to  copy  such  a  model, 
that  his  genius  strove  in  vain  against  obstacles  which  no 
painter  could  overcome.  The  dark  room  gave  him 
nature  to  the  life  ;  it  was  life,  truth,  and  colour  which 
he  daily  contemplated  on  his  screen.  '  Why,'  cried  he, 
'cannot  I  retain  these  inimitable  wonders  which  the 
sun's  rays  draw  at  the  focus  of  my  lens  ?  Why  cannot  I 
fix  the  image,  engrave  it  for  ever  ? ' 

Thus  Daguerre  nourishes  this  fantastic  dream  in- 
cessantly in  his  brain.  He  has  not  knowledge  enough 
to  comprehend  all  the  difficulties  of  such  a  problem,  nor 


20  THE  HISTORY   OF   PHOTOGRAPHY. 

is  he  ignorant  enough  to  believe  that  its  solution  is  an 
impossibility.  He  is  acquainted  with  Professor  Charles' 
experiment ;  he  has  heard  talk  of  the  shadows  which  im- 
print themselves  so  clearly  on  the  sensitised  paper ;  he 
feels  that  the  first  step  has  been  taken,  that  a  supreme 
effort  might  enable  a  bold  mind  to  bridge  the  abyss 
which  separates  the  isolated  fact  from  the  grand  solu- 
tion. This  effort  it  will  be  his  aim  to  accomplish.  For 
the  future  he  will  have  no  rest  until  he  can  exclaim,  like 
Archimedes,  '  I  have  found.' 

Daguerre  used  very  often  to  go  to  the  shop  of 
Chevalier,  the  optician  on  the  Quai  de  L'Horloge,  in 
order  to  procure  all  the  apparatus  he  could  pertaining 
to  the  dark  room. 

'  It  was  very  seldom,'  says  Charles  Chevalier  himself,^ 
'  that  he  did  not  come  at  least  once  in  the  week  to 
our  studio.  As  may  be  easily  imagined,  the  subject  of 
conversation  did  not  vary  much,  and  if  now  and  then  it 
digressed  a  little,  it  was  only  to  return  with  fresh  ardour 
to  the  arrangement  of  the  dark  room,  the  form  of  lenses, 
or  the  purity  of  the  pictures  ! ' 

At  this  time  Chevalier's  shop  was  much  frequented 
by  amateurs  and  others  who  came  to  obtain  from  the 
optician  similar  information  to  that  which  Daguerre  was 

'   Guide  du  Photographe.    Paris,  1 854. 


DAGUERRE.  21 


in  quest  of.  Chevalier  mentions  a  circumstance  which 
occurred  at  his  shop  in  1825,  which  seems  to  us  so 
curious  that  we  have  felt  bound  to  relate  it,  as  one  of  the 
stirring  chapters  in  the  history  of  the  fixation  of  the 
image  of  the  camera. 

One  day  a  young  man,  poorly  dressed,  timid, 
miserable,  famished-looking,  entered  the  optician's 
shop ;  he  approached  Chevalier,  who  was  alone,  and 
said  to  him,  *  You  are  making  a  new  camera  in  which 
the  ordinary  lens  is  replaced  by  a  convergent  meniscus 
glass  :  what  is  the  price  ? ' 

The  optician's  reply  made  his  questioner  turn  yet 
paler.  The  cost  of  the  object  in  question  was  doubtless 
as  far  above  his  means  as  if  it  had  been  equal  to  the 
riches  of  Peru  or  California.  He  lowered  his  head  sadly 
without  speaking. 

'May  I  enquire,'  continued  Chevalier,  'what  you 
intend  doing  with  a  camera  ?' 

'  I  have  succeeded,'  replied  the  unknown,  '  in  fixing 
the  image  of  the  camera  on  paper.  But  I  have  only  a 
rough  apparatus,  a  deal  box  furnished  with  an  object- 
glass  ;  by  its  aid  I  can  obtain  views  from  my  window. 
I  wished  to  procure  your  improved  camera  lens  in 
order  to  continue  my  experiments  with  a  more  powerful 
and  certain  apparatus.' 


22  THE   HISTORY   OF   PHOTOGRAPHY. 

Whilst  listening  to  these  words  Chevalier  said  to 
himself,  *  Here  is  another  of  these  poor  fools  who  want 
to  fix  the  image  of  the  camera  obscura!'  He  well 
knew  that  the  problem  engaged  the  minds  of  such  men 
as  Talbot  and  Daguerre,  but  none  the  less  deemed  it  a 
Utopian  dream. 

*  I  know,'  said  he,  *  several  men  of  science  who  are 
engaged  with  this  question,  but  as  yet  they  have 
arrived  at  no  result.     Have  you  been  more  fortunate?' 

At  these  words  the  young  man  pulled  out  an  old 
pocket-book  which  was  quite  in  keeping  with  his  dress  ; 
he  opened  it  and  quietly  drew  out  a  paper  which  he 
placed  on  the  counter. 

*  That,'  said  he,  '  is  what  I  can  obtain.'  Chevalier 
looked  at  it  and  could  not  control  his  astonishment ;  he 
saw  on  this  paper  a  view  of  Paris  as  sharp  as  the  image 
of  the  camera.  It  was  not  a  drawing  nor  a  painting  ; 
one  might  have  said  it  was  the  shadow  of  the  roof, 
chimneys,  and  dome  of  the  Pantheon.  The  inventor 
had  fixed  the  view  of  Paris  as  seen  from  his  window. 

Chevalier  questioned  the  young  man  further,  and  the 
latter  then  drew  from  his  pocket  a  vial  containing  a 
blackish  fluid.  *  You  have  here,'  said  he,  '  the  liquid 
with  which  I  operate,  and  if  you  follow  my  instructions 
you  will  obtain  like  results.' 


DAGUERRE.  23 


The  unknown  explained  to  the  optician  how  he 
should  go  to  work  ;  then  he  retired,  lamenting  his  hard 
fate  which  would  not  permit  him  to  possess  that  object 
of  his  dreams,  a  new  camera !  He  promised  to  return, 
but  disappeared  for  ever. 

Chevalier  endeavoured  to  put  in  practice  the  instruc- 
tions he  had  just  received  ;  but  it  was  in  vain  that  he 
made  his  experiments,  he  obtained  absolutely  no  result 
with  the  liquid  of  his  unknown  visitor.  It  is  probable 
that  he  did  not  operate  under  good  conditions,  and  it 
is  even  possible  that  he  omitted  to  prepare  his  sensitised 
paper  in  the  dark.  He  waited  long  for  another  visit 
from  the  unknown,  feeling  somewhat  remorseful  at 
having  been  so  reserved.     He  never  saw  him  again. 

The  name  of  this  poor  inventor  is  lost.  It  was  never 
discovered  what  became  of  him.  It  may  be,  alas  !  that 
an  almshouse  bed  was  his  last  refuge. 

Chevalier  related  this  curious  episode  to  Daguerre, 
who  paid  little  attention  to  it  while  he  carelessly  ex- 
amined the  remainder  of  the  stranger's  black  liquid  ;  his 
mind  was  too  preoccupied  with  researches  of  its  own  to 
attach  much  value  to  the  work  of  another. 

It  will  thus  be  se^n  that  the  history  of  this  unknown 
person  is  worthy  of  fixing  the  attention  for  a  moment; 
for,  though  it  was  fruitless,  it  is  but  fair  to  mention  it  as 


24  THE   HISTORY  OF   PHOTOGRAPHY. 

the  work  of  a  man,  of  genius  perhaps,  whom  poverty 
has  fatally  condemned  to  oblivion  ! 

But  to  return  to  Daguerre.  We  find  him  pursuing 
his  researches  with  fresh  energy.  He  has  constructed  a 
regular  laboratory  provided  with  all  the  necessary  appa- 
ratus and  innumerable  chemicals  ;  he  studied  the  re- 
agents, he  experimented  unceasingly,  ever  anxious  to 
attain  a  result  looked  upon  as  chimerical  by  men  of 
science.  Ere  long  Daguerre  declared  that  he  had  suc- 
ceeded in  fixing  the  fugitive  image,  but,  nevertheless, 
gave  no  proof  whatever  that  he  had  done  so.  In  De- 
cember 1825  he  told  everyone  who  would  listen  to  him 
that  the  great  problem  was  at  last  solved.  '  I  have 
seized  the  light,'  he  cried  with  enthusiasm ;  '  I  have 
arrested  its  flight!  The  sun  himself  in  future  shall  draw 
my  pictures ! ' 

A  few  days  later,  in  January  1826,  he  called  on 
Chevalier  to  talk  of  his  favourite  subject.  *  Besides  the 
young  man  I  spoke  to  you  about,'  said  the  optician,  '  I 
know  a  person  in  the  country  who  flatters  himself  that 
he  has  obtained  the  same  result  as  you.  He  has  for  a 
very  long  time  occupied  himself  with  reproducing  en- 
gravings by  the  action  of  light  on  certain  chemical 
agents.  Perhaps  you  would  do  well  to  put  yourself  in 
communication  with  him.' 


DAGUERRE.  25 


*  And  what  is  the  name  of  my  fortunate  rival  ? '  de- 
manded Daguerre. 

Chevalier  wrote  a  few  words  on  a  piece  of  paper 
which  he  handed  to  Daguerre.  On  it  was  this  address — 
*  M.  Niepce,  proprietaire,  au  Gras,  pres  Chalons-sur- 
Saone.' 

'^  A  few  days  afterwards  Daguerre  addressed  a  letter 
to  this  stranger,  which  the  latter,  with  provincial  mis- 
trust, threw  into  the  fire  as  soon  as  he  had  read,  content- 
ing himself  with  murmuring  between  his  teeth,  '  There 
is  another  of  those  Parisians  who  would  like  to  pump 
me!'^  It  was  under  these  auspices  that  the  relations 
between  the  two  inventors  commenced ;  they  were, 
however,  later  on  to  unite  their  labours  to  create,  as  it 
were  in  common,  an  art  which  will  be  looked  upon 
for  centuries  to  come  as  one  of  the  prodigies  of  our 
epoch. 

^  History  of  the  Discovery  improperly  called  '■Daguerreotype,^  preceded  by  a 
Notice  of  its  real  Inventor,  the  late  M.  Joseph  Nice phore  Niepce,  by  his  Son, 
Isidore  Niepce.     Paris,  1841. 


26  THE   HISTORY  OF   PHOTOGRAPHY. 


CHAPTER   III. 

NICEPHORE     NIEPCE. 

THE  TWO  BROTHERS  NIEPCE — THEIR  YOUTH — THEIR  WORKS — THE 
PYRfiLOPHORE— HYDRAULIC  MACHINE— NIC^PHORE'S  RESEARCHES 
IN    HELIOGRAPHY — RESULTS    OBTAINED. 

JOSEPH-NlCEPHORE  NiEPCE  was  born  at  Chalons-sur- 
Saone  on  March  7,  1765.  His  life  and  works  are  so 
interwoven  with  those  of  his  elder  brother  Claude,  to 
whom  he  was  devotedly  attached,  that  their  history  is  a 
joint  one,  like  that  of  the  Brothers  Montgolfier.  We 
shall  see  them  walk  side  by  side  through  life,  mutually 
sustaining  and  helping  each  other. 

Their  father,  Claude  Niepce,  was  steward  to  the 
Duke  of  Rohan-Chabot ;  their  mother  was  the  daughter 
of  a  celebrated  barrister,  Barault  by  name. 

'Joseph  and  his  brother  Claude,'  says  one  of  their 
biographers,  '  were  brought  up  with  great  care  and  soli- 
citude by  their  father.  Their  tutor  was  the  Abbe 
Montangerand,  a  very  clever  man. 

*   .  .  .    The   brothers  made  rapid   progress   in  Ian- 


NICEPHORE  NIEPCE.  2/ 

guages,  sciences,  and  belles-lettres.  They  had  real  love 
for  learning,  and  being  of  gentle  and  tinfid  dispositions, 
were  content  in  themselves,  not  joining  in  the  games 
and  amusements  usual  to  children  of  their  age.  They 
seemed  born  for  the  contests  of  the  mind  and  intel- 
lect. Nicephore  and  Claude  employed  their  play 
time  in  constructing  little  machines  of  wood  with  cog 
wheels,  with  the  aid  of  their  knives  only.  These 
machines  worked  well,  to  the  great  joy  of  their  makers  ; 
they  imitated  the  raising  and  lowering  movements  of  the 
crane.'  ^ 

Nicephore  Niepce,  like  Daguerre,  like  all  the  men  of 
his  time,  had  to  submit  to  the  influence  of  the  great 
Revolution.  On  May  lo,  1792,  he  changed  the  clerical 
dress,  which  he  had  till  then  worn,  for  the  military  cos- 
tume, and  entered  as  sub-lieutenant  in  the  42nd  regi- 
ment of  the  line. 

Young  Niepce  was  made  lieutenant  on  the  i6th 
Floreal  of  the  year  I.  of  the  Republic  (May  6,  1793), 
and  took  part  in  the  expedition  to  Cagliari,  in  Sardinia. 

*  We  borrow  these  remarks  on  the  life  of  Niepce  from  a  remarkable  and 
rare  pamphlet  by  M.  Victor  Fouque,  entitled  The  Truth  with  respect  to  the 
Invention  of  Photography.  Nicephore  Niepce^  his  Life,  Essays,  and  Works, 
fro7n  his  Correspondence  and  other  unpublished  Documents.  Paris,  1867.  The 
author  of  this  pamphlet,  which  excited  great  attention  on  its  first  appear- 
ance, has,  unhappily,  fallen  into  totally  erroneous  ideas  with  regard  to 
Daguerre,  to  whom  he  would  deny  any  part  in  the  creation  of  photography. 


28  THE  HISTORY  OF   PHOTOGRAPHY. 

The  same  year  (1793)  he  figures  in  the  ranks  of  the 
army  of  Italy,*partaking  in  its  glorious  exploits.  The 
1 8th  Ventose,  year  II.  (March  9,  1794)  he  was  appointed 
assistant  to  adjutant-general  Frottier,  shortly  after  he 
was  suddenly  attacked  by  a  severe  and  dangerous  ill- 
ness, which  obliged  him  to  leave  the  regiment  and  seek 
an  asylum  in  the  town  of  Nice.  There,  thanks  to  the 
care  of  the  mistress  of  the  house  in  which  he  lived, 
Madame  Romero,  and  the  devotion  of  her  daughter 
Mademoiselle  Marie-Agnes,  he  regained  his  health.  But 
whilst  regaining  his  health  he  had  been  losing  his  heart, 
which  he  at  last  offered  to  Miss  Marie-Agnes,  and  they 
were  married  the  17th  Thermidor  of  the  year  II. 
(August  5,  1794). 

But  the  illness  he  had  undergone  had  affected  his 
constitution,  and,  obliged  to  give  up  his  military 
career,  he  retired  to  Saint  Roch,  near  Nice,  where  he 
lived  with  his  wife  and  his  brother  Claude.  It  was 
during  their  stay  at  Saint  Roch  that  the  brothers 
conceived  the  idea  of  a  motive  power  to  propel 
ships  without  the  aid  of  sails  or  oars.  The  machine 
which  the  brothers  invented  was  put  in  motion  by  hot 
air  ;  they  gave  it  the  name  of  the  pyrdophore,  and,  as 
soon  as  they  returned  to  their  native  town  of  Chalons, 
they  fitted  up  a  boat  with  their  new  apparatus  and  ran 


NICEPHORE   NIEPCE.  29 

it  on  the  Saone.  Later  on,  when  the  Government 
of  the  First  Empire  ofifered  prizes  for  an  improved 
hydraulic  machine  to  take  the  place  of  Marly's,  the 
brothers  Niepce  sent  in  the  model  of  a  pump  which  was 
as  simple  as  it  was  ingenious,  and  for  this  new  system,  as 
also  for  their  pyrelophore,  they  were  thanked  by  the 
Institute. 

During  the  Continental  blockade,  the  Government 
called  on  men  of  science  if  possible  to  replace  the  indigo 
procured  from  abroad,  and  so  useful  in  dyeing  wools,  by 
ivoad,  the  juice  of  which  might  in  some  way  be  employed 
in  the  art  of  dyeing.  In  answer  to  the  appeal  the  brothers 
turned  their  attention  to  the  subject,  and  materially 
helped  to  lay  the  foundation  of  a  new  culture.  In  the 
years  preceding  the  fall  of  the  First  Empire  they  ren- 
dered the  greatest  services  to  France. 

But  the  two  brothers  were  soon  obliged  to  separate. 
In  181 1  Claude  quitted  the  paternal  roof  at  Chalons, 
never  to  return,  and  went  to  Paris.  His  purpose  was  to 
launch  the  pyrelophore,  and  the  great  town  seemed  to 
him  to  be  the  only  place  where  his  work  might  at  length 
be  crowned  with  success.  But  against  the  invincible 
obstacles  in  his  way  all  his  efforts  were  in  vain  ;  he 
failed  alike  in  his  trials  and  in  his  applications. 

He  left  Paris  and   France  and   settled  definitely  at 


30  THE   HISTORY   OF   PHOTOGRAPHY. 

Kew  near  London.  The  two  brothers,  thus  separated 
by  exigency  and  distance,  kept  up  an  unbroken  corre- 
spondence, which  M.  Foque  has  published  in  his  beau- 
tiful book  dedicated  to  the  memory  -of  one  of  the 
inventors  of  photography.  These  letters  are  a  rare 
example  of  mutual  affection  and  solicitude,  in  which  the 
ingenious  conceptions  of  the  laborious  minds  are  as 
numerous  as  the  marks  of  affection  of  tender  and  devoted 
hearts. 

Living  alone  in  his  country-house  at  des  Gras  near 
Chalons,  Nicephore  Niepce  devoted  himself  assiduously 
to  his  researches,  which  were  encouraged  by  the  quiet 
country  life  and  sweet  solitude  of  the  paternal  home. 

It  was  a  simple  and  modest  building,  this  cradle  of 
photography,  shaded  by  a  few  trees  and  situate  on  the 
bank  of  the  Sa6ne,  which  gave  it  a  sweet  and  vivifying 
freshness.  Under  this  humble  roof,  Niepce  devoted  ten 
years  of  his  life  to  solving  the  problem  of  the  fixing  of 
the  picture  of  the  camera  obscura. 

After  his  numerous  researches  in  the  making  of  new 
machines,  in  the  cultivation  of  woad,  &c.,  Nicephore 
turned  his  attention  into  a  new  direction,  when  litho- 
graphy made  its  appearance  in  France.  This  great  dis- 
covery of  the  German  Aloys  Senefelder  was  brought 
into   France  in   1802   by  the  Count  de  Lasteyrie-Dus- 


NIC^PHORE  NIEPCE.  3  I 

saillant,  who,  ten  years  after  his  first  attempts,  founded 
an  admirable  Lithographic  Institution  in  Paris.  This 
new  art  met  with  universal  success.  Niepce  partook 
of  the  general  enthusiasm,  became  enraptured  with 
lithography,  and  taught  himself  how  to  use  its  appliances ; 
but,  far  from  Paris,  he  could  not  procure  proper  appa- 
ratus and  stones,  he  therefore  determined  to  make  them 
for  himself. 

'In  1813,'  writes  his  son  Isidore  Niepce,  'my  father 
made  some  attempts  at  engraving  and  reproducing 
drawings,  by  lithography,  which  had  recently  been  in- 
troduced into  France,  and  which  attracted  his  admi- 
ration. Some  broken  stones,  intended  for  repairing 
the  main  road  between  Chalons  and  Lyons,  which  came 
from  the  Quarries  of  Chagny,  seemed  to  him  to  be 
suited,  from  the  fineness  of  their  grain,  to  be  usefully 
employed  in  lithography.  We  chose  some  of  the  largest 
of  these  stones,  and  my  father  had  them  polished  by  a 
marble-worker  of  Chalons  ;  I  then  made  various  drawings 
on  them,  which  my  father  coated  with  a  varnish  he  had 
prepared  ;  he  then  etched  them  by  means  of  an  acid. 

'  But  finding  that  the  grain  of  these  stones  was  not 
sufficiently  fine  and  regular,  my  father  replaced  them  by 
polished  tin  plates  ;  he  coated  these  plates  with  various 
varnishes,  then  placed  on  them  the  drawings  which  he 


32  THE   HISTORY   OF   PHOTOGRAPHY. 

had  previously  varnished  to  render  them  transparent,  and 
exposed  the  whole  to  the  action  of  light.  This  was 
the  commencement,  very  imperfect  if  you  like,  of  helio- 
graphy.' 

Once  on  the  road  to  discovery,  Niepce  continued  his 
studies  with  that  unwearying  perseverance  of  which  the 
inventor  seems  to  have  the  sole  monopoly. 

He  was  not  long  in  having  recourse  to  the  camera, 
but  he  was  alone  in  a  country  far  from  any  scientific 
centre,  and  he  had  to  tax  his  ingenuity  and  make  for 
himself  what  he  wanted  ;  he  was  his  own  cabinet-maker 
and  optician,  he  manufactured  his  cameras  and  his  ap- 
paratus, and  as  a  rest  from  his  labours  took  the  pen  and 
opened  his  heart  to  his  dear  Claude.  His  progress  in 
heliography  was  rapid,  as  is  proved  by  the  following 
letter  (a  remarkable  document  and  precious  for  the  his- 
tory of  photography),  dated  May  5,  18 18,  which  we  repro- 
duce entire  : — 

'  You  have  seen,'  he  says  to  his  brother,  *  that  I  had 
broken  the  object-glass  of  my  camera  ;  but  that  I  had 
another  which  I  hoped  to  be  able  to  make  use  of  My 
attempt  was  a  failure  ;  this  glass  has  a  shorter  focus  than 
the  diameter  of  the  box,  and  so  I  could  not  make  use  of 
it.  We  went  to  town  last  Monday  ;  I  could  only  find  at 
Scotti's  a  lens  of  longer  focus  than  the  first,  and  I  have 


nic:6phore  niepce.  33 


had  to  lengthen  the  tube  which  holds  it,  and  by  means  of 
which  the  exact  focus  is  adjusted.  We  returned  here 
Wednesday  evening  ;  but  since  then  the  weather  has 
always  been  dull,  preventing  me  from  continuing  my 
experiments ;  moreover,  I  am  too  worried  and  fatigued 
with  paying  or  receiving  visits  to  be  able  to  give  much 
attention  to  them.  I  would  prefer,  I  assure  you,  to  live 
in  a  desert. 

*  When  my  object-glass  was  broken,  no  longer 
being  able  to  make  use  of  my  camera,  I  made  an  arti- 
ficial eye  with  Isidore's  ring  box,  a  little  thing  from 
16  to  18  lines  square.  I  had,  luckily,  the  lenses  of  the 
solar  microscope,  which,  as  you  know,  belonged  to,  our 
grandfather  Barrault.  One  of  these  little  lenses  proved 
to  be  exactly  of  the  focus  wanted  ;  and  threw  a  picture 
of  objects  in  a  very  sharp  and  life-like  manner  on  to  a 
field  of  thirteen  lines  diameter. 

'  I  placed  this  little  apparatus  in  my  workroom  facing 
the  open  window  looking  on  to  the  pigeon-house.  I 
made  the  experiment  in  the  way  you  are  acquainted  with, 
my  dear  friend,  and  I  saw  on  the  white  paper  the  whole 
of  the  pigeon-house  seen  from,  the  window,  and  a  faint 
impression  of  the  window  frame  itself  which  was  not  ex- 
posed to  the  sunlight.  One  could  distinguish  the  effects 
of  the  solar  rays  in  the  picture  from  the  pigeon-house  up 

D 


34  THE   HISTORY   OF   PHOTOGRAPHY. 

to  the  window-sash.  This  is  but  a  very  imperfect  ex- 
p)eriment,  but  the  images  of  the  objects  were  extremely 
minute.  The  possibility  of  painting  by  this  means 
appears  almost  clear  to  me ;  and  if  I  am  able  to  perfect 
my  process,  I  shall  hasten  to  respond  to  the  interest 
which  I  know  you  will  take  in  it,  by  imparting  it  to  you. 
I  do  not  hide  from  myself  that  there  are  great  diffi- 
culties, especially  as  regards  fixing  the  colours,  but  with 
work  and  patience  one  can  accomplish  much.  What 
you  had  foreseen  has  proved  true.  The  ground  of 
the  picture  is  black,  and  the  objects  are  white,  that  is 
to  say  lighter  than  the  ground.' 

In  the  course  of  his  correspondence  with  his  brother, 
Nicephore  continually  mentions  his  efforts,  researches, 
and  experiments.  On  May  19,  18 16,  he  says  to  him,  *  I 
shall  occupy  myself  with  three  things ;  1st.  To  give 
more  relief  to  the  representation  of  the  objects.  2nd.  To 
transpose  the  colours  [by  this  must,  most  likely,  be 
understood,  to  reproduce  the  exact  tones  of  nature]  ;  3rd 
and  lastly  to  fix  them,  which  will  not  be  easy.'  On  the 
28th  of  the  same  month  he  sent  Claude  four  metallic 
plates  which  bore  impressions  produced  by  light.  Un- 
fortunately, it  is  impossible  to  know  what  substance 
Nicephore  used  for  sensitising  his  plates  ;  through  pru- 
dence and  from  fear  of  some  indiscretion  he  never  men- 
tions it  in  any  of  his  letters.     His  writings,  however,  show 


NIC^PHORE   NIEPCE.  35 

US  that  whatever  it  was,  h£  was  not  satisfied  with  it ;  for 
he  says  later  on,  in  a  letter  to  his  brother,  that  he  had 
been  trying  to  make  use  of  alcoholic  solutions  of  chloride 
of  iron.  In  1817,  he  had  recourse,  in  h\s  Heliographic 
studies,  as  he  already  calls  them,  to  chloride  of  silver,  and 
then  to  organic  matters  such  as  guaiacum  (a  resin),  and 
at  last  to  phosphorus,  which,  as  is  well  known,  from  white 
turns  gradually  to  a  red  colour  under  the  action  of  light. 
But  he  was  not  long  in  love  with  this  new  agent,  which 
he  very  justly  terms  a  '  dangerous  combustible.' 

On  July  2,  1 8 17,  he  declares  that  his  efforts  have 
not  yet  been  completely  successful,  but  he  adds,  with- 
out losing  hope,  '  I  have  not  varied  my  experiments 
sufficiently  to  consider  myself  as  beaten,  and  I  am  by  no 
means  discouraged.' 

Here  the  interesting  documents  relating  to  the  early 
history  of  photography  cease  for  a  time  ;  no  letter  of 
Niepce's  for  the  next  nine  years  (18 17-1826)  is  to  be 
found  ;  but  it  is  certain  that  the  illustrious  and  pains- 
taking inventor  never  abandoned  his  researches.  In  1826 
we  find  him  stopping  definitely  at  balm  of  Judcea,  a 
resinous  substance  which,  when  spread  out  thinly  and 
exposed  to  the  light,  turns  white  and  becomes  in* 
soluble  in  essence  of  lavender.  When  placed  at  the 
focus  of  the  camera  a  whitish  delineation  of  the  picture 


36  THE   HISTORY   OF   PHOTOGRAPHY. 


thrown  on  to  it  is  obtained.  In  possession  of  this  fact, 
which  he  had  so  patiently  conquered  at  the  price  of  the 
most  persevering  researches,  Niepce  was  enabled  to  re- 
produce engravings  by  the  action  of  light  and  fix  in  a 
transient  manner  the  image  of  the  camera. 

As  regards  the  first  point,  Niepce  varnished  the  back 
of  the  engraving  to  be  reproduced,  thus  rendering  it  trans- 
parent ;  then  he  placed  it  on  a  tin  plate  which  had  pre- 
viously been   covered  with  a  thin  coat  of  bitumen   of 
Judaea.  The  transparent  parts  of  the  engraving,  i.e.  those 
which  had  not  come  in  contact  with  the  ink,  allowed  the 
light  to  pass  through  and  whiten  the  bitumen  of  Judaea. 
A  tolerably  faithful  copy  of  the  engraving  placed  on  it 
was  thus  obtained  on  the  metal  plate,  which  was  then 
plunged  into  a  bath  of  essence  of  lavender  in  order  to 
dissolve  those  parts  of  the  bitumen  which  had  been  pro- 
tected from  the  light.     The  picture  thus  obtained  was 
permanent,  the  light  having  no  further  action  on  it. 

But  this  reproduction  of  engravings  could  only  be 
considered  as  a  scientific  curiosity ;  the  grand  problem 
was  the  fixing  of  the  image  of  the  camera.  Niepce  laid 
down  the  first  plans  for  its  solution. 

He  placed  at  the  focus  of  his  camera  a  tin  plate 
coated  with  bitumen  of  Judaea.  The  light  whitened  the 
resin  wherever  it  fell  on  it,  and  rendered  it  insoluble  in 


NICEPHORE   NIEPCE.  37 

essence  of  lavender.  The  exposed  plate  was  plunged 
into  a  bath  of  the  fixing  liquid,  which  dissolved  only 
those  parts  of  the  bitumen  not  affected  by  the  light ;  a 
photograph  was  thus  obtained  in  which  the  lights  corre- 
sponded to  the  lights  and  the  shadows  to  the  shadows ;  the 
former  being  produced  by  the  whitened  resin,  the  latter 
by  the  metal  laid  bare  by  the  solvent. 

These  metallic  pictures,  as  may  be  supposed,  were 
not  of  any  great  value ;  they  were  feeble,  pale,  and  dull. 
Niepce  endeavoured  to  strengthen  the  tones  by  exposing 
the  plate  to  vapours  of  iodine  or  sulphuret  of  potassium ; 
but  his  attempts  were  in  vain.  In  his  hands  the  new 
art  of  Heliography  made  no  further  progress ;  the  in- 
ventor, exhausted  by  ten  years  of  labour,  had  done  his 
part. 

Niepce's  invention,  important  though  it  was,  was  but 
the  germ  of  photography,  and  was  subject  to  some 
grave  defects.  Bitumen  of  Judaea  is  a  substance  which 
is  only  acted  upon  very  slowly  and  feebly  by  light. 
It  was  necessary  to  expose  the  metal  plate  in  the 
camera  for  more  than  ten  hours ;  the  sun  displaced  the 
lights  and  shades  during  this  long  space  of  time,  the 
picture  was  therefore  wanting  in  sharpness  and  definition. 

Niepce's  chief  aim  was  to  apply  his  discovery  to  tho 
reproduction  of  engravings ;    he  succeeded  in  etching 


38  THE   HISTORY  OF   PHOTOGRAPHY. 


with  an  acid  those  parts  of  his  plates  not  protected 
by  the  resinous  coating  which  had  been  rendered  in- 
soluble by  the  action  of  the  light,  and  was  thus  enabled 
to  produce  a  plate  for  printing  from  as  in  the  copper- 
plate press.  He  thus  invented  Heliography,  and  during 
his  lifetime  an  artist  named  Lemaitre  published  some 
truly  remarkable  prints  by  this  ingenious  process. 

But  the  apparatus  which  Niepce  had  to  work  with 
was  imperfect ;  his  cameras  were  roughly  and  badly 
made,  his  lenses  were  greatly  inferior  to  those  of  the 
present  day ;  in  spite  of  his  fertile  imagination,  in  spite 
of  his  unceasing  toil,  the  boldness  of  his  conceptions,  and 
his  indomitable  perseverance,  this  great  *  working  man '  of 
science  could  do  no  better  with  such  poor  tools.  Niepce, 
we  repeat,  went  no  farther.  Perhaps  he  did  unwisely  in 
abandoning  the  salts  of  silver  which  his  predecessor 
had  employed,  perhaps  he  occupied  himself  too  ex- 
clusively with  the  reproduction  of  drawings,  but,  how- 
ever it  may  have  been,  it  is  certain  he  had  not  the 
slightest  idea  of  the  developing  agents^  i.e.  the  substances 
used  at  the  present  time  for  the  purpose  of  making  the 
latent  picture,  which  has  been  mysteriously  printed  on 
the  photographic  plate,  gradually  appear.  Some  writers 
have,  indeed,  unjustly  endeavoured  to  deprive  Daguerre 
of  the  glory  which  is  rightly  his,  as  we  shall  see,  in  the  in- 


NICEPHORE   NIEPCE.  39 

vention  of  photography,  in  ascribing  it  solely  to  Niepce. 
Whilst  recognising  the  latter  as  a  great  mind  and  ac- 
cording him  all  the  marks  of  admiration  which  are  his 
due,  let  us  not  separate  his  name  from  that  of  his 
future  associate,  Daguerre.  The  inventor  of  the  Diorama 
would  perhaps  have  done  nothing  without  a  predecessor, 
but  he  far  surpassed  the  work  of  Niepce.  If  Daguerre 
did  not  conquer  his  America  until  another  had  pointed 
out  the  way  he  should  follow,  he  had  at  least  the  glory 
of  following  to  the  very  end  this  road  bristling  with 
barriers  and  impediments. 

The  history  of  photography  has  been  handled  by 
some  writers  with  regrettable  prejudice  ;  their  sincerity 
we  are  far  from  suspecting,  but  they  have  certainly 
allowed  themselves  to  wander  from  the  truth,  pro- 
bably because,  without  sufficient  scientific  knowledge, 
they  were  incapable  of  rightly  understanding  even  the 
principles  of  photography.  To  add  to  Niepce's  fame 
they  have  tried  entirely  to  suppress  the  name  of  Daguerre 
in  the  history  of  the  art.  We  believe  we  are  keeping 
within  the  bounds  of  strict  impartiality  in  repeating 
that  the  names  of  Niepce  and  Daguerre  should  be  placed 
together  ;  each  of  these  great  minds  has  had  its  part  in 
the  work  we  are  studying. 


40  THE  HISTORY  OF   PHOTOGRAPHY. 


CHAPTER   IV. 

'    THE     NIEPCE-DAGUERRE    PARTNERSHIP. 

CORRESPONDENCE  EXCHANGED  BETWEEN  THE  TWO  INVENTORS— DIS- 
TRUST AND  RESERVE  OF  NIEPCE — HIS  JOURNEY  TO  PARIS — HIS 
INTERVIEWS  WITH  DAGUERRE  — HIS  JOURNEY  TO  LONDON — ACT  OF 
PARTNERSHIP— DEATH    OF    NIEPCE. 

We  have  seen  with  what  mistrust  the  first  letter  from 
Daguerre  to  Niepce  was  received  by  the  latter.  The 
inventor  of  the  Diorama  allowed  almost  a  whole  year  to 
pass  without  giving  further  attention  to  the  matter,  but 
at  the  end  of  January  1827  he  again  wrote  to  Niepce, 
telling  him  explicitly  that  he  was  engaged  in  fixing  the 
image  of  the  camera,  and  that  he  had  arrived  at  im- 
portant though  very  imperfect  results.  He  solicited  a 
mutual  exchange  of  the  secrets  of  which  each  was  in 
possession.  On  receipt  of  this  request,  Niepce,  without 
abandoning  his  prudent  reserve,  and  after  making  en- 
quiries about  Daguerre  of  Lemaitre  (whom  he  had  en- 
trusted with  the  working  of  his  heliographic  plates),  and 
after  receiving  a  favourable  reply  from  that  celebrated 
engraver,  wrote  as  follows  to  the  Parisian  painter : — 


the  niepce-daguerre  partnership.         4i 

'Monsieur  Daguerre, 

'  I  received  yesterday  your  reply  to  my  letter  of  the 
25th  January,  1826.  For  the  last  four  months  I  have 
been  unable  to  work  ;  the  bad  weather  entirely  prevent- 
ing me.  I  have  perfected  in  an  important  degree  my 
process  for  engraving  on  metal,  but  the  results  obtained 
not  having  as  yet  furnished  me  with  sufficiently  correct 
proofs,  I  am  unable  to  comply  with  your  wish.  This  I 
regret  more  for  myself  than  for  you,  Sir,  as  your  process 
is  very  different,  and  promises  you  a  degree  of  supe- 
riority of  which  engraving  will  not  admit  ;  this,  however, 
does  not  hinder  me  from  wishing  you  all  imaginable 
success.' 

It  will  be  seen  that  Niepce,  strong  in  his  work, 
refuses  as  yet  to  disclose  his  secrets.  This  industrious 
and  persevering  genius  knew  the  difficulties  of  the 
problem,  and  believed  that  no  one  was  better  able  to 
solve  them  than  himself.  The  compliments  which  he 
pays  Daguerre  evidently  hide  a  little  delicate  irony  under 
their  prudent  laconicism. 

But  Daguerre  would  not  be  repulsed.  Anxious  to 
become  acquainted  with  the  processes  of  the  experimenter 
of  Chalons,  he  sent  him  a  picture  resembling  a  sepia 
drawing  done  by  a  process  of  his  own.      This  fact  is 


42  ,       THE  HISTORY  OF  PHOTOGRAPHY. 

confirmed  by  a  letter  which  M.  Foque  reproduces  in  his 
interesting  historical  work. 

*  I  forgot  to  tell  you  in  my  last  letter,'  writes  Niepce 
to  Lemaitre,  the  engraver,  under  date  of  April  3,  1827, 
*  that  M.  Daguerre  has  written  to  me  and  sent  me  a  little 
picture  very  elegantly  framed,  done  d  la  sepia^  and 
finished  by  his  process.  This  drawing  which  represents 
an  interior,  is  very  effective,  but  it  is  difficult  to  determine 
exactly  what  is  the  result  of  the  process  as  the  pencil 
has  intervened.  Perhaps  you.  Sir,  are  already  acquainted 
with  this  kind  of  drawing,  which  the  inventor  calls 
smoked  pictureSy  and  which  are  for  sale  at  Alphonse 
Giroux's. 

*  Whatever  may  have  been  Monsr.  Daguerre's  inten- 
tion, as  one  good  turn  deserves  another,  I  have  sent  him 
a  tin  plate  lightly  etched  by  my  process,  choosing  as  the 
subject  one  of  the  engravings  which  you  sent  me.  This 
communication  cannot  in  any  way  compromise  my 
discovery.' 

Shortly  afterwards  Daguerre  received  a  little  case 
from  Chalons  containing  a  tin  plate  engraved  by  Niepce's 
heliographic  process.  But  the  prudent  Nicephore  had 
taken  care  to  wash  the  proof  so  thoroughly  that  not  the 
slightest  trace  of  the  bitumen  of  Judaea  was  to  be  found 
on  it.      This  engraving  was,  however,  as  Niepce  himself 


THE   NIEPCE-DAGUERRE   PARTNERSHIP.  43 

says,  very  defective,  and  much  too  feeble.  *  I  expect, 
Sir,'  adds  the  inventor  of  hehography,  *  that  you  have 
followed  up  your  former  attempts  ;  you  were  succeeding 
too  well  not  to  go  on  !  We  areoccupied  with  the  same 
object,  we  should  find  an  equal  interest  in  our  mutual 
efforts  to  attain  the  same  end.  I  shall  hear  with  much 
pleasure  that  the  new  experiment  which  you  were  to 
make  with  your  improved  camera  has  been  successful  as 
you  expected.  In  that  case,  Sir,  and  if  it  is  a  fair  offer, 
for  my  part  I  shall  be  as  desirous  of  knowing  the  result 
as  I  shall  be  flattered  to  offer  you  such  of  my  researches 
of  a  similar  nature  as  I  am  occupied  with.' 

It  will  be  seen  that  the  two  inventors  are  being 
gradually  drawn  together  by  a  bond  of  union.  Here  is 
Niepce  making  an  offer  to  Daguerre  ;  he  consents  to 
give  him  his  secrets  in  exchange  for  those  which  the 
latter  may  have  to  impart. 

But  an  event  was  about  to  occur  which  would  bring 
these  two  geniuses  together.  In  the  month  of  August 
1827,  Nicephore  received  intelligence  that  his  brother 
Claude  was  seriously  ill,  and  that  his  life  was  in  danger. 
Nicephore,  accompanied  by  his  wife,  started  for  England ; 
he  had  to  pass  through  Paris,  and  being  unexpectedly 
detained  there  some  days,  he  took  advantage  of  his 
stay  in  the  capital  to  see  Lemaitre  and  Daguerre.     The 


44 


THE  HISTORY  OF   PHOTOGRAPHY. 


details  of  his  curious  interview  with  the  inventor  of  the 
Diorama  are  preserved  to  us  in  a  very  interesting  letter, 
which  we  do  not  hesitate  to  reproduce  entire. 


Fig.  5. 


t'j.y.o.r« 


JOSEPH    NIEPCE. 


'I  have  had,'  writes  Niepce,  on  September  4,  1827, 
to  his  son  Isidore,  'several  long  interviews  with  M. 
Daguerre.  He  came  to  see  us  yesterday,  and  stayed 
three  hours  ;  we  are  to  visit  him  again  before  we  leave, 


THE  NIEPCE-DAGUERRE   PARTNERSHIP.  45 

and  I  don't  know  how  long  we  may  stay,  as  it  will  be 
for  the  last  time,  and  we  cannot  find  enough  to  say  on 
the  interesting  subject  of  our  interviews. 

*  I  can  only  repeat  to  you,  my  dear  Isidore,  what  I 
said  to  M.  de  Champmartin.  I  have  seen  nothing  here 
which  has  given  me  more  pleasure  than  the  Diorama. 
M.  Daguerre  himself  conducted  us  there,  and  we  were 
able  to  contemplate  at  our  ease  the  most  magnificent 
views.  The  view  of  the  interior  of  St.  Peter's,  at 
Rome,  by  M.  Bouton  is  certainly  admirable  and  perfect 
in  its  illusion.  But  none  are  finer  than  the  two  scenes 
painted  by  M.  Daguerre  ;  the  one  of  Edinburgh  by 
moonlight  at  the  time  of  a  fire ;  the  other  of  a  Swiss 
village  taken  from  the  entrance  of  the  main  road  and 
opposite  a  prodigious  mountain,  covered  with  eternal 
snows.  These  representations  are  so  faithful  even  in  the 
most  insignificant  details,  that  one  seems  to  see  wild  and 
savage  nature,  with  all  the  enchantment  which  is  lent  it 
from  the  charms  of  colour  and  the  magic  of  light  and 
shade.  The  illusion  is  even  so  complete  that  one  is 
tempted  to  leave  one's  seat  and  cross  the  plain  to 
clamber  to  the  summit  of  the  mountain.  This  I  assure 
you  is  not  the  least  exaggeration  on  my  part.  The  objects 
either  were  or  appeared  to  be  of  their  natural  size.  They 
are   painted    on    a    canvas    or   taffeta    covered  with   a 


46  THE   HISTORY   OF    PHOTOGRAPHY. 

varnish  having  the  drawback  of  sticking,  which  necessi- 
tates care  when  these  species  of  decorations  have  to  be 
rolled  for  transport,  as  it  is  difficult  in  unrolling  to 
avoid  tearing. 

*  But  to  return  to  M.  Daguerre.  I  told  you,  my  dear 
Isidore,  that  he  persists  in  thinking  I  am  farther  ad- 
vanced than  he  in  the  researches  in  which  we  are  engaged. 
What  is  at  least  plain  now  is  that  his  process  and  mine 
are  totally  different.  His  has  something  marvellous 
about  it,  and  a  celerity  of  action  comparable  to  the 
electric  fluid.  M.  Daguerre  has  succeeded  in  fixing  on 
his  chemical  substance  some  of  the  colours  of  the  solar 
spectrum  ;  he  has  already  united  four  and  hopes  to 
obtain  the  other  three,  and  thus  to  have  the  complete 
spectrum.  But  the  difficulties  he  encounters  increase 
in  proportion  to  the  modifications  which  the  substance 
itself  must  undergo  in  order  to  be  able  to  retain  several 
colours  at  the  same  time ;  a  great  hindrance,  and  one 
which  foils  him  completely,  is  that  totally  opposite  effects 
are  produced  by  these  combinations.  Thus  a  blue  glass, 
which  produces  a  deeper  shade  on  the  said  substance, 
produces  a  clearer  tint  than  the  part  exposed  to  the 
direct  action  of  light.  Then  again  in  this  fixing  of  the 
primary  colours  the  results  obtained  are  so  feeble  that 
the  fugitive  tints  are  invisible  in  broad  daylight ;  they  can 


THE   NIEPCE-DAGUERRE   PARTNERSHIP.  47 

only  be  seen  in  an  obscure  light,  and  for  this  reason  : 
the  substance  in  question  is  of  the  nature  of  Bolognese 
stone  (sulphate  of  barytes)  and  pyrophorus  ;  it  is  very 
readily  acted  upon  by  light,  but  cannot  retain  the  effect, 
because  a  somewhat  prolonged  exposure  to  the  action  of 
the  sun  ends  by  decomposition.  M.  Daguerre  himself 
does  not  pretend  to  fix  the  coloured  representations  of 
objects  by  this  process;  even  if  he  succeeds  in  surmount- 
ing all  the  obstacles  in  the  way,  he  will  only  be  able  to 
make  use  of  it  as  a  sort  of  intermediary  means.  From 
what  he  has  said  to  me,  he  seems  to  have  little  hope  of 
succeeding,  and  his  researches  will  hardly  have  any 
object  but  pure  curiosity.  My  process  appears  to  him 
to  be  certainly  preferable,  and  much  more  satisfactory 
as  regards  the  results  which  I  have  obtained.  He  is 
sensible  how  interesting  it  would  be  to  obtain  pictures  by 
aid  of  a  process  equally  simple,  easy,  and  expeditious. 
He  wishes  that  I  should  make  some  experiments  with 
coloured  glass  in  order  to  see  if  the  impression  pro- 
duced on  my  substance  is  the  same  as  that  on  his.  I 
shall  procure  five  of  these  from  Chevalier,  who  has 
already  made  them  for  M.  Daguerre.  The  latter  insists 
principally  on  rapidity  of  action  in  the  fixation  of  the 
pictures  ;  a  very  essential  condition  indeed,  and  which 
must  be  the  first  object  of  my  researches.      As  regards 


48  THE   HISTORY   OF   PHOTOGRAPHY. 

the  method  of  engraving  on  metal,  he  is  far  from  de- 
preciating it ;  but  as  it  would  be  necessary  to  retouch 
and  to  deepen  the  impressions,  he  thinks  that  this  process 
would  succeed  only  very  imperfectly  for  views.  He 
thinks  that  for  this  sort  of  engraving  the  employment 
of  glass  and  hydrofluoric  acid  would  be  much  preferable. 
He  is  convinced  that  lithographic  ink,  carefully  applied 
to  the  surface  bitten  by  the  acid,  would  produce  on  a 
white  paper  the  effect  of  a  good  proof,  and  would  more- 
over have  a  certain  originality  about  it  which  would  be  still 
more  attractive.  The  chemical  composition  employed  by 
Daguerre  is  a  very  fine  powder  which  does  not  adhere  to 
the  surface  on  which  it  is  spread,  and  must  therefore  be 
kept  horizontal.  This  powder  on  the  least  contact  with 
light  becomes  so  luminous  that  the  camera  is  quite  lit  up 
by  it.  This  substance,  as  far  as  I  can  remember,  is  very 
analogous  to  sulphate  of  baryta  (cawk),  or  Bolognese 
stone,  which  also  has  the  property  of  retaining  certain 
prismatic  rays.     .     .     . 

*  Our  places  are  taken  for  Calais,  and  our  departure 
is  definitely  fixed  for  next  Saturday  at  eight  in  the  morn- 
ing. We  were  unable  to  secure  the  places  earlier,  the 
King's  journey  to  Paris  having  attracted  many  people  in 
that  direction. 

'Adieu — our  best  love  to  Jenny,  yourself,  and  the 
youngster.' 


THE   NIEPCE-DAGUERRE   PARTNERSHIP.  49 

Nicdphore,  on  arriving  in  England,  found  his  brother 
Claude  dangerously  ill,  enfeebled  by  work,  and  his  mind 
affected  through  over-study.  He  remained  some  weeks 
at  Kew,  and  made  the  acquaintance  of  a  distinguished 
Englishman,  Sir  Francis  Baur,  who  undertook  to  lay  the 
results  of  his  heliographic  researches  before  the  Royal 
Society  of  London.  But  Niepce  would  not  reveal  his 
discoveries,  and  the  learned  English  Society  accepts  no 
communication  from  an  inventor  who  keeps  his  processes 
secret. 

Nicephore  soon  returned  to  Chalons  and  kept  up  a 
lively  correspondence  with  Daguerre,  ending  by  a  pro- 
posal to  enter  into  a  partnership  with  him.  After  much 
hesitation  and  many  delays,,  the  inventor  of  the  Diorama 
at  length  visited  Niepce  at  Chalons,  and  there  they 
signed  an  agreement. 

In  accordance  with  this  agreement  Niepce  and 
Daguerre  were  mutually  to  acquaint  each  other  with  their 
processes.  They  were  to  work  out  and  improve  these 
processes  in  common,  and  together  attain  the  object  of 
their  labours,  viz.,  the  fixation  of  the  image  of  the  tamera. 
The  company  thus  formed  was  to  go  by  the  name  of  the 
Niepce-Daguerre  ;  its  place  of  business  was  at  Paris  ;  and 
the  proceeds  of  working  the  new  discovery  were  to  be 
divided  between  the  two  partners. 


50  THE   HISTORY   OF   PHOTOGRAPHY. 


After  signing  this  agreement  Niepce  acquainted 
Daguerre  with  the  processes  which  he  employed  in  pre- 
paring his  heh'ographic  plates.  Feeble  indeed  was  the 
result,  as  we  have  already  seen.  But  the  inventor  of  the 
Diorama  had  even  less  to  give  for  the  little  he  received. 
He  returned  to  Paris  after  seeing  Niepce's  apparatus  in 
action,  resolved  to  work  without  ceasing  until  success 
crowned  his  efforts. 

'  Suddenly,'  says  Charles  Chevalier,  *  Daguerre  be- 
came invisible.  Shut  up  in  a  laboratory  which  he  had 
had  constructed  in  the  Diorama  building,  where  he 
resided,  he  set  to  work  with  fresh  ardour,  studied 
chemistry,  and  for  nearly  two  years  lived  almost  con- 
tinuously in  the  midst  of  books,  assay  crucibles,  retorts, 
and  melting  pots.  I  have  caught  a  glimpse  of  this 
mysterious  laboratory,  but  neither  I  nor  anyone  else  was 
ever  allowed  to  enter  it.  Madame  Daguerre,  Messrs. 
Bonton,  Sebon,  Carpentier,  etc.  can  bear  witness  to  the 
truth  of  these  recollections.' ' 

In  the  midst  of  his  researches  and  experiments, 
Daguerre  was  at  last  favoured  with  one  of  those  accidents 
which  often  happen  to  the  persevering  worker.  He  had 
left  a  silver  spoon  on   a  metal  plate  which  had   been 

*  Guide  du  Photographe  {^Souvenirs  Historiques). 


THE  NIEPCE-DAGUERRE   PARTNERSHIP.  5 1 

treated  with  iodine,  what  was  his  surprise  to  find  on  lift- 
ing the  spoon  that  its  image  was  clearly  and  sharply 
imprinted  on  the  iodised  surface  ! 

This  observation  was  a  precious  revelation  to 
Daguerre.  He  abandoned  the  bitumen  of  Judaea,  and 
substituted  for  it  iodide  of  silver,  which  darkens  with 
wonderful  rapidity  under  the  action  of  light.  To  make  his 
preparation,  he  exposed  a  silvered  plate  to  the  influence 
of  vapours  of  iodine,  and  he  thus  obtained  a  surface 
which  impressed  itself  with  the  picture  thrown  on  it  by 
the  lens  of  the  camera.  But  the  plate  only  presented  a 
faint  shadowy  image  of  the  picture  which  existed  still  in 
a  latent  state ;  after  trying  numberless  chemical  sub- 
stances and  agents  of  every  description,  Daguerre  at 
last  discovered  that  petroleum  oil  possessed  the  property 
of  developing  the  image  on  his  plate.  This  discovery 
was  a  great  step  towards  success  ;  Daguerre  had  put  his 
hand  on  a  developing  agent.  He  did  not  rest  con- 
tent here,  but  went  on  unceasingly,  and  at  last  substituted 
for  petroleum  oil  the  vapours  of  mercury,  causing  the  in- 
visible image  which  the  light  had  printed  on  the  iodised 
silver  .plate,  to  appear  as  if  by  magic  and  with  mar- 
vellous  distinctness. 

Photography  was  henceforth  a  fact.  Daguerre  had 
not  failed  to  write  to  his  partner  :  he  told  him   of  his 


52  THE   HISTORY   OF   PHOTOGRAPHY. 

having  made  use  of  iodide  of  silver,  but  Niepce  did  not 
believe  in  the  efficacy  of  this  substance.  Before  learning 
the  almost  definite  results  which  Daguerre  had  obtained, 
he  was  seized  with  congestion  of  the  brain  and  died 
July  5,  1833. 


53 


CHAPTER   V. 

THE   DAGUERREOTYPE. 

DAGUERRE'S  researches  and  studies — HE  CEDES  HIS  INVENTION  TO 
THE  STATE— ARAGO  AND  THE  DAWN  OF  PHOTOGRAPHY— A  BILL 
LAID  BEFORE  THE  HOUSE— REASONS  FOR  ITS  BEING  PASSED — MEET- 
ING  OF  THE  ACADEMY  OF   SCIENCES,    AUGUST    ID,    1839, 

Daguerre  is  thus  left  alone  to  solve  the  problem — a 
task  which,  in  spite  of  its  many  difficulties,  he  had 
determined  to  accomplish.  The  ingenious  artist  has 
discovered  a  fact  full  of  promise ;  he  has  seen  that  the 
image,  traced  so  to  speak  in  a  latent  state  by  the  light 
on  a  plate  coated  with  iodised  silver,  gradually  reveals 
itself,  that  is  to  say  becomes  visible  and  manifest,  when 
exposed  to  the  action  of  vapour  of  mercury.  The  in- 
ventor held  in  his  hand  the  thread  which  would  conduct 
him  in  the  labyrinth  of  his  enquiries  ;  he  was  no  longer 
working  in  the  dark,  for  he  was  in  possession  of  the  guide 
which  would  lead  him  to  the  light. 

But  the  days  and  months  passed  in  continual  labours, 
and  it  was  only  at  the  price  of  two  years  entirely  devoted  to 


54  THE   HISTORY   OF   PHOTOGRAPHY. 

toil  that   Daguerre  at  last  perfected  the  beautiful   art 
which  was  to  immortalise  his  name. 

In  1835,  Daguerre  was  in  a  position  to  acquaint 
Isidore  Niepce,  son  of  Nicephore,  with  the  improvements 
which  he  had  effected.  It  was  time  to  publish  the  dis- 
covery of  heliography.  An  additional  clause  was  added 
to  the  before-mentioned  agreement.  Two  more  years 
were  passed  in  constant  toil  and  study.  At  length  in 
1837,  Daguerre  and  Isidore  Niepce  signed  a  regular  act 
of  partnership  and  endeavoured  to  start  a  company  to 
work  the  new  discovery. 

On  March  15, 1838,  the  subscription  was  opened  ;  but 
the  incredulous  public  did  not  respond  to  the  call ;  funds 
were  not  forthcoming  ;  capitalists  seemed  to  run  away 
from  the  new  art  of  photography.^ 

^  To  give  a  true  idea  of  the  impression  which  the  appearance  of  the 
Daguerreotype  produced,  we  give  almost  entire  an  article  which  appeared 
in  the  Moniteiir  [/niversel  of  ]anvia.ry  14,  1839;  at  this  time,  the  results 
obtained  by  Daguerre  were  already  known,  and  were  the  universal  theme 
in  all  the  papers. 

'The  discovery  of  M.  Daguerre,'  says  the  writer  of  the  article,  'has  been 

for  some  time  past  a  subject  of  some  wonderful  accounts After 

fourteen  years  of  research  M.  Daguerre  has  succeeded  in  fixing  the  natural 
light  on  a  solid  surface,  in  giving  a  body  to  the  impalpable  and  fugitive 
image  of  objects  reflected  in  the  retina  of  the  eye,  in  a  mirror,  in  the 
apparatus  of  the  camera  obscura.  Figure  to  yourself  a  glass  which  after 
receiving  your  image  presents  you  your  portrait,  as  indelible  as  painting, 
and  much  more  faithful. 

'  What  is  the  inventor's  secret  ?     What  is  the  substance  endowed  with 
such  astonishing  sensibility  as  not  only  to  become  penetrated  with  light,  but 


THE  DAGUERREOTYPE.  55 

Daguerre  then  decided  to  cede  his  invention  to  the 
State.  He  addressed  himself  to  several  men  of  science 
and  knocked  at  Arago's  door.  The  illustrious  astronomer 
and  man  of  science  was  thunderstruck  at  first  sight  of 
the  Daguerreotype  plate,  and  was  boundless  in  his  ex- 
pressions of  admiration.     The  inventor  had  found  his 


also  to  retain  the  impression,  thus  operating  at  the  same  time  like  the  eye 
and  like  the  optical  nerve,  like  the  material  instrument  of  the  sensation  and 
like  the  sensation  itself?  Indeed  we  cannot  say.  M.  Arago  and  M.  Biot, 
who  have  read  reports  on  the  effects  of  M.  Daguerre' s  discovery,  have 
declined  to  define  their  causes.  By  the  courtesy  of  the  inventor  we  have 
been  able  to  examine  his  chefs-d^ auvre^  in  which  Nature  herself  is  drawn. 

*  Each  picture  placed  before  us  called  forth  some  admiring  exclamation. 
What  fineness  of  touch  !  what  harmony  of  light  and  shade  !  what  delicacy  ! 
what  finish  \  .  .  ,  .  With  a  magnifying  glass  we  can  see  the  slightest  fold 
in  a  stuff,  the  lines  of  a  landscape  invisible  to  the  naked  eye,  ....  In  a 
view  of  Paris  we  can  count  the  paving  stones — we  see  the  dampness  pro- 
duced by  rain  ;  we  can  read  the  name  on  a  shop.  All  the  threads  of  the 
luminous  tissue  have  passed  from  the  object  into  the  image.' 

A  little  further  on  the  writer  indulges  in  a  singular  supposition  : — 

*  M,  Daguerre,'  he  says,  '  has  as  yet  only  made  experiments  at  Paris,  and 
these  experiments,  even  under  the  most  favourable  circumstances,  have 
always  taken  so  much  time  as  only  to  enable  him  to  obtain  complete  results 
of  nature  inanimate  or  at  rest,  movement  escapes  him  or  only  leaves  vague 
and  indefinite  traces.  It  is  presumable  that  an  Afi-ican  sun  would  give  him 
instantaneous  autographs  of  nature  in  action  and  in  life.' 

The  author  concludes  with  more  sensible  remarks: — 'The  discovery, 
as  far  as  at  present  developed,  to  judge  from  the  results  which  we  have 
seen,  promises  to  be  of  great  importance  to  art  and  science.  Some  persons 
seem  to  be  afraid  that  it  will  leave  nothing  for  draughtsmen,  and  perhaps 
even  for  painters,  to  do.  It  seems  to  us  that  it  can  only  prove  prejudicial  to 
the  copyist.  We  have  never  heard  that  the  invention  of  moulding  on  nature 
has  put  the  genius  of  the  sculptor  in  the  shade.  The  discovery  of  printing 
did  serious  injury  to  the  scribes,  but  not  to  the  writers.' 


$6  THE  HISTORY  OF   PHOTOGRAPHY. 

advocate.  Arago  sent  him  to  Duchatel,  the  then  Home 
Minister,  who  offered  Daguerre  and  Isidore  Niepce  Hfe 
pensions  (modest  enough  ! )  in  exchange  for  their  secrets. 

On  June  15,  1839,  Duchatel  laid  before  the  House  a 
bill  relating  to  the  new  discovery,  preceded  by  the  fol- 
lowing reasons  for  its  acceptance  : — 

'  You  all  know,  and  some  among  you  have  already 
been  able  to  prove  for  yourselves,  that  after  fifteen  years 
of  persevering  and  costly  research,  M.  Daguerre  has  suc- 
ceeded in  fixing  the  image  of  the  camera,  and  of  thus 
creating,  in  four  or  five  minutes  by  the  aid  of  light, 
drawings  in  which  the  objects  preserve  their  forms,  even 
to  the  slightest  detail,  in  which  linear  perspective  and  the 
degradation  of  tone  produced  by  aerial  perspective  are 
reproduced  with  a  delicacy  hitherto  unknown. 

'  It  is  not  necessary  to  dwell  upon  the  utility  of  such 
an  invention.  It  will  easily  be  understood  what  new 
facilities  it  must  offer  for  the  study  of  the  sciences  ;  and 
as  to  the  arts,  the  services  it  can  render  to  them  are 
incalculable. 

'  These  reproductions  so  true  to  nature  would  be  a 
constant  object  of  study  to  artists  and  painters,  even  the 
most  talented  ;  and  on  the  other  hand,  this  process  offers 
them  a  ready  and  easy  means  of  forming  collections  of 
studies  which,  if  they  made  themselves,  they  could  only 


THE   DAGUERREOTYPE.  57 

obtain  at  the  cost  of  much  time  and  labour  and  in  a  much 
less  perfect  manner, 

'  The  art  of  the  engraver  would  take  a  new  degree  of 
interest  and  importance,  when  employed  to  reproduce 
and  multiply  these  pictures  drawn  by  Nature  herself 

'  Finally,  to  the  traveller,  to  the  archaeologist,  as  well 
as  the  naturalist,  the  apparatus  of  M.  Daguerre  would 
become  a  continual  and  indispensable  necessity.  It  will 
enable  them  to  fix  their  impressions  without  having  re- 
course to  the  hand  of  a  stranger.  Every  author  would 
become  his  own  illustrator ;  he  would  halt  a  few  seconds 
before  the  most  extensive  view,  and  obtain  on  the  spot 
an  exact  facsimile  of  it. 

*  Unfortunately  for  the  inventors  of  this  beautiful 
discover}'-,  they  find  it  impossible  to  make  a  matter  of 
business  of  it,  and  to  indemnify  themselves  for  the  sacri- 
fices which  were  necessitated  by  such  numerous  attempts 
so  long  fruitless. 

*  Their  invention  is  not  one  which  can  be  protected 
by  a  patent.  As  soon  as  it  is  known,  anyone  can  make 
use  of  it.  The  most  awkward  person  will  be  able  to 
make  pictures  as  exact  as  a  practised  artist.  It  thus 
follows  that  this  process  must  belong  to  all  the  world  or 
remain  unknown.  And  what  just  regrets  would  not  be 
expressed  by  all  the  lovers  of  art  and  science  if  such  a 


58  THE   HISTORY   OF    PHOTOGRAPHY. 

secret  remains  impenetrable  to  the  public,  if  it  must  be 
lost  and  die  with  the  inventors  ! 

'  In  such  an  exceptional  circumstance  it  behoved  the 
Government  to  intervene.  It  is  for  it  to  put  society  in 
possession  of  the  discovery  which  it  demands  to  enjoy  in 
the  general  interest  by  giving  to  its  authors  the  price,  or 
rather  the  recompense,  of  their  invention. 

*  These  are  the  motives  which  have  led  us  to  conclude 
a  provisional  agreement  with  Messrs.  Daguerre  and 
Niepce,  for  which  the  object  of  the  bill  we  have  the 
honour  to  lay  before  you  is  to  ask  your  sanction. 

*  Before  acquainting  you  with  the  bases  of  this  treaty, 
it  will  be  necessary  to  give  a  few  more  details. 

*  The  possibility  of  transiently  fixing  the  image  of 
the  dark  room  has  been  known  for  the  last  century ;  but 
this  discovery  promised  no  useful  results  ;  the  substance 
on  which  the  solar  rays  pictured  the  image  had  not  the 
property  of  retaining  it,  and  became  completely  black  as 
soon  as  exposed  to  the  light  of  day. 

'  M.  Nicephore  Niepce  invented  a  means  of  render- 
ing these  pictures  permanent.  But,  although  he  had 
solved  this  difficult  problem,  his  invention  still  remained 
very  imperfect.  He  could  obtain  only  the  outline  of 
objects,  and  he  required  at, least  twelve  hours  to  obtain 
the  slightest  drawing. 


THE   DAGUERREOTYPE. 


59 


'  It  was  by  totally  different  means,  and  by  putting 
aside  the  traditions  of  M.  Niepce,  that  M.  Daguerre  has 
been  able  to  arrive  at  the  admirable  results  which  we 


Fig.  6. 


DAGUERKE. 


have  witnessed,  namely,  the  extreme  rapidity  of  the  ope- 
ration, the  reproduction  of  aerial  perspective,  and  all  the 
play  of  light  and  shade.  M.  Daguerre's  method  is  his 
own  ;  it  belongs  to  him  alone,  and  is  distinguished  from 


6o  THE   HISTORY  OF   PHOTOGRAPHY. 

that  of  his   predecessor  as   much   in  its  cause  as  in  its 
effects. 

'At  the  same  time,  as  before  the  death  of  M.  N. 
Niepce  an  agreement  was  made  between  him  and  M. 
Daguerre,  by  which  they  engaged  to  share  mutually  all 
the  advantages  they  might  receive  from  their  discoveries, 
and  as  this  stipulation  has  been  extended  to  M.  Isidore 
Niepce,  it  is  impossible  to  treat  alone  with  M.  Daguerre, 
even  respecting  the  process  which  he  has  not  only  per- 
fected but  invented.  It  must  not  be  forgotten,  moreover, 
that  M.  Niepce's  invention,  although  it  is  still  im- 
perfect, is  perhaps  susceptible  of  being  improved  and  of 
being  employed  usefully  under  certain  circumstances  ;  it 
is  therefore  of  importance  to  history  and  science  that  it 
should  be  published  at  the  same  time  as  that  of  M. 
Daguerre. 

'  These  explanations  will  show  you,  Gentlemen,  for 
what  reason  and  by  what  title  Messrs.  Daguerre  and 
Isidore  Niepce  are  made  parties  in  the  agreement  which 
you  will  find  annexed  to  the  bill.' 

After  reading  this  document,  which,  believing  im- 
partiality cannot  be  too  strictly  adhered  to  in  history, 
we  have  thought  it  our  duty  to  reproduce  entire,  the 
Home  Minister  read  the  bill  which  assigned  a  life  pension 
of  6,000  francs  a  year  to  M.  Daguerre,  and  to  Isidore 


THE   DAGUERREOTYPE.  6 1 

Niepce  a  life  pension  of  4,000  francs  a  year,  the  half  of 
each  pension  being  reversionary  to  the  widows  of 
Daguerre  and  Niepce. 

One  is  astounded  at  the  smallness  of  the  sums  ac- 
corded in  exchange  for  one  of  the  grandest  of  modern 
inventions,  the  importance  of  which  was  well  understood, 
and  from  which  there  was  no  doubt  great  results  would 
be  obtained.  It  is  true  something  was  added  to  the 
value  of  these  pensions  by  ornamenting  them  with  the 
name  of  National  Reward.  But  if  the  Government  was 
thus  careful  of  the  public  money,  the  nation  at  least 
was  lavish  in  bestowing  on  Daguerre  the  marks  of  its 
great  enthusiasm  and  admiration,^ 

The  bill  was  passed  with  acclamation  by  the  House 
and  also  by  the  House  of  Peers.  Arago,  as  perpetual 
secretary  of  the  Academy  of  Sciences,  was  charged  to 

'  In  oui-  historical  account  we  have  rendered  to  Daguerre  the  glory 
which  is  due  to  him  in  the  invention  of  photography,  A  distinguished 
writer,  who  has  done  us  the  honour  to  notice  our  work  in  the  press,  has 
accused  us  of  partiality  in  saying  that  Nicephore  Niepce  was  the  real  dis- 
coverer of  the  art  in  question,  Daguerre  has  been  violently  attacked  by  a  son 
of  Nicephore,  dispossessed  of  his  titles  by  M,  Victor  Fouque,  a  critic, 
evidently  sincere,  but  whose  ignorance  in  the  matter  of  chemical  reagents 
has  drawn  him  aside  from  the  truth.  We  have  endeavoured  to  judge  imparti- 
ally the  old  disputes  which  have  been  brought  forward,  and  we  make  bold  to 
say  that  we  have  retraced  the  facts  in  the  light  in  which  they  ought  to  be 
studied.  Is  it  necessary  to  add  that  in  our  work  the  researches  of  the 
illustrious  inventor  of  the  Daguerreotype  have  been  estimated  by  the  light 
of  historical  documents,  that  is  to  say  without  any  preconceived  ideas  ? 


62  THE   HISTORY   OF   PHOTOGRAPHY. 

communicate  to  that  learned  society  the  description  of 
the  Daguerreotype  process.  This  was  the  name  by 
which  the  marvellous  discovery  was  to  be  henceforth 
known. 

August    10,    1839,  was  the  day  fixed,   and  crowds 
of  people  curious  to  hear  the  secret  thronged  the  ap- 
proaches to  the  Institut.     On  this  exceptional  occasion 
the  Academy  of  the  Fine  Arts  had  assembled  at  the 
Academy    of    Sciences.     The    seats    reserved    for   the 
public  were  filled  with  those  whom   Paris  counted  her 
most  eminent  men.      Every   eye  was  fixed    upon  Da- 
guerre,  who,  in  his  modesty,  shunned  the  public  gaze, 
and    seemed   to  wish  to  divest   himself  of  a   triumph 
which  the  great  Arago  had  taken  under  his  special  care. 
It   would    not   be    necessary  to  know  the    Parisian 
public,  so  eminently  impressionable  and  easily  excited, 
to  ask  if  the  approaches  to  the  Institut  were  crowded 
with  people.     All  that  Paris  contained  in  the  shape  of 
artists,  of  young  students,  and  inquisitive   persons  were 
to  be  found  at  the  doors  of  the  Mazarin  Palace.     Arago 
had  spoken ;    his  words  were   repeated  by  a   hundred 
mouths,  they  circulated  in  the  corridors,  they  burst  forth 
on  the  quays,  where  comments  flew  about  more  or  less 
explicit.  *  It  is  the  iodide  of  silver  and  mercury,'  cried  one 
person.'  *  No,'  said  another,  '  it  is  the  bitumen  of  Judaea.' 


THE  DAGUERREOTYPE.  63 

*  It  is  nitrate  of  silver,  I  tell  you,'  replied  a  third.  Such 
exclamations  as  these  were  bandied  about,  but  none 
had  understood  anything  about  Daguerre's  secret. 

Meanwhile  the  time  passed,  the  papers  appeared 
containing  accounts  of  the  solemn  sitting  of  the 
Academy ;  they  explained  more  clearly  the  Daguerreo- 
type process.  The  opticians  made  experiments  and  ex- 
posed cameras  and  the  necessary  apparatus  for  taking 
Daguerreotypes  in  their  shop-windows  ;  these  were  at 
once  pounced  upon  and  disputed  for  by  everybody  who 
could  afford  to  buy  them,  and  all  Paris  had  caught  the 
Daguerreotype  fever.  The  artists  were  seized  with 
astonishment  and  admiration :  Paul  Delaroche  sought 
out  Daguerre,  obtained  a  Daguerreotype  plate  from 
him  and  showed  it  everywhere,  exclaiming — '  Painting  is 
dead  from  this  day !' 

The  art  of  Raphael  and  Michael  Angelo  was  not 
killed  ;  on  the  contrary,  it  was  to  find  new  resources  in 
the  inspirations  of  a  great  inventor,  and  Science  was 
about  to  give  her  hand  to  Art ! 


64  THE   HISTORY   OF   PHOTOGRAPHY. 


CHAPTER  VL     ^ 

THE   PROGRESS   OF  A   NEW   ART. 

THE  DAGUERREOTYPE  PROCESS — ACCELERATING  SUBSTANCES— IMPROVED 
LENSES— PORTRAITS— FIXING  AGENTS  —DISCOVERY  OF  PHOTOGRAPHY 
ON    PAPER    BY    TALBOT — M.    BLANQUART-EVRARD. 

Soon  after  the  memorable  sitting  of  August  lo,  the 
processes  of  Daguerre  were  known  to  all  Paris,  all 
France,  and  one  may  even  say,  for  so  rapid  was  the 
success  of  the  new  art,  to  the  entire  civilised  world. 

All  over  the  capital  cameras  were  to  be  seen, 
perched  on  the  balconies  of  houses,  on  the  boulevards, 
before  the  monuments,  everywhere.  But  these  newly- 
improvised  photographers  obtained  for  the  most  part  but 
poor  results  ;  the  pictures  they  sought  to  fix  in  their 
cameras  were  generally  indistinct,  and  showing  perhaps 
but  a  few  secondary  objects  of  the  coveted  view.  The 
method  was  simple  and  precise,  but  it  required,  never- 
theless, a  certain  amount  of  practice  in  its  delicate 
manipulations,  and  it  required  some  time  even  for  a  good 
operator  to  make  it  profitable. 


THE   PROGRESS   OF   A   NEW   ART.  65 

The  photographic  images  obtained  by  the  henceforth 
illustrious  inventor  of  the  Diorama  were  formed  on  the 
surface  of  a  plate  of  silvered  copper.  The  first  opera- 
tion was  to  iodise  the  silver.  The  silvered  plate  had  to 
be  perfectly  polished  and  clean.  First  of  all  it  had  to 
be  rubbed  with  a  pad,  or  buff  polisher  (fig.  7),  in  order 
to  give  it  the  utmost  possible  brilliancy,  and  to  remove 
from  its  surface  the  slightest  trace  of  any  foreign 
particles  which  might  have  got  attached  to  it. 

Fiff.  7- 


DAGl'ERREOTYPE    POLISHER. 


The  silvered  plate  thus  prepared  was  placed  in  the 
iodising  box,  in  which  it  was  supported  by  a  frame  over 
crystals  of  iodine. 

The  fumes  of  iodine  act  on  the  silver,  combine  with 
it,  and  form  a  yellow  coating  of  iodide  of  silver. 

The  plate  thus  sensitised  is  then  exposed  in  the 
camera,  where  it  receives  the  image  projected  on  to  the 
prepared  surface  at  the  focus  of  the  lens.  The  rays  of 
light   which    form  the  image  decompose  the  iodide  of 

F 


66 


THE    HISTORY    OF   PHOTOGRAPHY. 


silver  just  in  proportion  to  their  intensity,  the  parts  ex- 
posed to  the  high  Hghts  of  the  picture  undergoing  the 
greatest  change,  while  in  the  shadows  the  iodised  surface 
remains   unaltered.      The  most   curious  feature  in  this 


Fig.  8. 


MERCURIAL   DEVELOPING   BOX. 


preliminary  stage  of  the  process  is,  that  the  plate  when 
removed  from  the  camera  presents  no  visible  signs  of 
chemical  change,  although  there  is  a  latent  image  caught 
in  the  most  delicate  beauty  of  light  and  shadow  upon  its 
surface.     In  order  to  render  this  image  visible  it  is  neces- 


THE   PROGRESS   OF  A   NEW   ART.  6") 

sary  to  submit  the  plate  to  the  operation  of  develop- 
ment, by  placing  it  in  a  box  above  a  bath  of  mercury  gently 
heated  to  a  temperature  of  about  50°  Reaumur,  ascer- 
tained by  a  thermometer.  (See  fig.  8.)  The  mercury 
emits  fumes  which,  coming  in  contact  with  the  prepared 
surface,  have  a  liking  for  and  condense  upon  the  parts 
decomposed  by  the  light,  while  the  shadows  protected  by 
unaltered  iodide  of  silver  are  shielded  from  the  attack  of 
this  subtle  developing  agent.  Thus  gradually,  as  if  by 
magic,  the  mysterious  plate  reproduces  every  detail  of 
the  scene  before  which  the  camera  has  been  placed. 

After  the  picture  has  been  developed  it  becomes 
necessary  to  fix  it,  as,  still  susceptible  to  the  influence  of 
light,  it  would  soon  be  blotted  from  the  surface  of  the 
plate.  In  order  then  to  remove  the  unaltered  iodide  of 
silver  it  is  immersed  in  a  solution  of  hyposulphite  of 
soda,^  which  clears  the  shadows  and  leaves  the  lights  and 
half-tones  of  the  image  intact. 

The  Daguerreotype  image  is  thus  fixed  and  is  formed, 
as  we  have  seen  of  a  delicate  coating  of  mercury ;  this 
metal,  spread  over  the  silvered  surface,  appears  brilliant  in 
the  lights,  whilst  in  the  shadows  it  has  not  taken  hold  ; 

'  The  use  of  hyposulphite  of  soda  as  a  photographic  developing  agent 
was  made  known  in  a  paper  by  Sir  John  Herschel,  published  soon  after  the 
invention  of  the  Daguerreotype  process. — Ed, 

F  2 


6S  THE   HISTORY   OF   PHOTOGRAPHY. 

the  latter  are  represented  by  the  polished  surface  of  the 
metal  plate,  where  the  developer  has  laid  it  bare.  But 
the  picture  thus  obtained  offered  several  grave  drawbacks. 
Its  mirror-like  nature  was  one  of  the  worst :  in  order 
to  see  the  picture  as  fixed  on  the  plate,  it  was  necessary 
to  hold  it  at  a  certain  angle  to  the  light,  and  it  often 
appeared  to  have  more  of  the  properties  of  a  mirror 
or  stained  tin  plate  than  of  an  artistic  drawing. 

In  Daguerre's  time  the  exposure  in  the  camera  had 
to  be  prolonged  for  at  least  fifteen  minutes  ;  consequently 
to  dream  of  taking  portraits  Avas  out  of  the  question; 
whilst  if  a  landscape  was  attempted,  the  masses  of 
verdure  were  represented  by  white  silhouettes  or  monoto- 
nous blots.^ 

Besides  these  inconveniences,  the  Daguerreotype 
would  not  resist  the  slightest  touch  ;  a  finger  passed  over 
it  destroyed  the  whole  picture  ;  moreover,  it  did  not  long 
remain  intact,  a  short  time  sufficed  to  deprive  it  of  its 
sharpness. 

These  difficulties  were,  however,  overcome.  A 
method  of  protecting  the  Daguerreotype  picture  by  a  pro- 
cess called  gilding  was  discovered.  This  process  consists 
in  imparting  a  hardness  to  the  coated  surface  by  means 

•  The  process  was  subsequently  accelerated  and  rendered  available  for 
portraiture  by  Goddard's  discovery  of  the  rapid  action  of  bromine.— Ed. 


THE   PROGRESS   OF  A  NEW  ART. 


69 


of  a  liquid  containing  gold  in  solution.     Hyposulphite 
of  gold  and  soda  give  excellent  results. 

This  salt  is  dissolved  in  a  large  quantity  of  water,  the 
Daguerreotype  plate  is  immersed  in  this  solution,and  then 
gently  heated  over  a  spirit  lamp,  as  shown  in  fig.  9. 


GILDING   THE  DAGUEKKEOTVPE   PLATE, 


It  is  a  fact  in  chemistry  that  one  oxidable  metal  will 
displace  another  less  easily  oxidable  ;  for  this  reason,  the 
mercury  is  dissolved  and  replaced  by  the  gold  on  the 
silvered  surface.     As  may  be  supposed,  after  this  substi- 


70  THE   HISTORY   OF   PHOTOGRAPHY. 

tution  of  gold  for  mercury,  the  picture  has  assumed  a 
different  aspect,  but  it  has  gained  notably  by  the  ex- 
change ;  it  has  acquired  vigour,  and  become  more  pleas- 
ing in  appearance,  and,  most  important  of  all,  is  capable 
of  resisting  moderate  rubbing.  When  the  gilding  is 
completed,  the  plate,  after  being  well  washed  to  remove 
the  excess  of  salt  is  then  dried,  and  finished. 

As  soon  as  Daguerre's  invention  was  known,  a  great 
number  of  artists  and  men  of  science  applied  themselves 
to  the  practice  and  improvement  of  it.  It  will  be  readily 
understood  that  an  essential  improvement  consisted  in 
diminishing  the  time  of  exposure  in  the  camera.  To 
arrive  at  this  result,  it  was  above  all  necessary  to  alter 
the  lens  which  produced  the  pictures.  Daguerre 
had  given  rules  which  fixed  the  dimensions  of  the  lens 
according  to  the  different  sizes  of  silvered  plates 
used.  But  these  observations  of  the  clever  experimen- 
talist referred  specially  to  the  reproduction  of  general 
views  of  landscapes  or  objects  at  a  distance.  From  all 
parts  came  anxious  enquiries  as  to  whether  the  Daguerreo- 
type would  not  produce  portraits ;  and  whether,  as  a 
writer  of  the  time  says,  the  prodigy  accomplished  in  a 
story  of  Hoffmann  was  not  soon  to  be  realised,  and,  to 
quote  the  words  of  the  author  of  the  '  Contes  fantas- 


THE  PROGRESS  OF  A   NEW  ART.  7 1 

tiques,' '  the  lover  would  present  his  mistress  with  a  mirror 
in  which  she  would  see  his  image.' 

To  solve  this  problem  it  was  indispensable  that  the 
focus  of  the  lens  should  be  shortened,  and  a  greater  quan- 
tity of  light  condensed  on  the  plate  in  order  to  illumi- 
nate more  vigorously,  and  thus  more  rapidly  impress 
the  sensitised  surface.  Charles  Chevalier  constructed 
a  camera  with  two  achromatised  object-glasses,  which 
gave  a  very  sharp  and  brilliantly  lighted  image. ^ 
With  this  improvement  the  time  of  exposure  was  reduced 
to  a  few  minutes. 

'  However,'  says  M.  L.  Figuier  in  his  excellent  essay 
on  photography,  *  this  most  important  problem  of  lessen- 
ing the  exposure  to  the  light  was  not  completely  solved 
till  1 84 1,  and  then,  thanks  to  a  discovery  of  great  value. 
Claudet,  a  French  artist,  who  had  bought  of  Daguerre 
the  exclusive  right  to  introduce  the  photographic  pro- 
cesses in  England,  discovered  the  properties  of  accelerat- 
ing substances.* 

In  photography  the  name  accelerator  is  given  to 
certain  substances  which,  when  applied  to  a  plate 
previously  iodised,  increase  in  an  extraordinary  degree 

'  The  double  combination  achromatic  portrait  lens  was  invented  by  Prof. 
Petzral  of  Vienna,  and  brought  to  a  high  degree  of  perfection  by  M. 
Voglander,  whose  lenses,  some  twenty  years  ago,  were  eagerly  sought  after, 
and  are  prized  by  photographers  at  the  present  day. — Ed. 


72  THE    HISTORY   OF   PHOTOGRAPHY. 

its  sensitiveness  to  light.  Alone,  these  substances  are 
non-photogenic  J  that  is  to  say  they  are  not  in  themselves 
capable  of  producing  a  combination  which  would  be 
chemically  influenced  by  light,  but  if  applied  to  a  plate 
already  iodised  they  give  it  the  property  of  receiving  the 
impress  of  an  object  in  a  few  seconds. 

The  substances  capable  of  thus  stimulating  the 
iodised  silver  are  numerous.  The  first,  introduced  by 
Claudet,  is  chloride  of  iodine ;  but  it  yields  considerably 
in  sensibility  to  substances  which  were  afterwards  dis- 
covered. The  fumes  of  bromine,  bromide  of  iodine, 
bromide  of  lime,  chloride  of  sulphur,  bromoform, 
chloric  acid,  Hungarian  liquid,  Resier's  liquid,  and 
Thierry's  liquid,  are  the  quickest-acting  accelerators: 
with  chloric  acid  perfect  pictures  have  been  obtained  in 
half  a  second. 

By  the  discovery  of  these  accelerating  substances 
Daguerreotypes  could  now  be  taken  of  animate  objects, 
and  thus  the  long-desired  portraits  were  at  length  attain- 
able. Already  in  1840,  attempts  had  been  made  to 
obtain  portraits  with  the  Daguerreotype ;  but  the  long 
exposure  necessarily  rendered  them  fruitless.  These 
attempts  were  made  with  the  long-focus  lens,  which  only 
admitted  a  light  of  feeble  intensity  into  the  camera  ;  it 
was  also  necessary  to  place  the  person  in  full  sun-light. 


THE   PROGRESS  OF  A   NEW  ART.  73 

and  prolong  the  exposure  for  a  quarter  of  an  hour  As 
it  is  impossible  to  keep  the  eyes  open  so  long  a  time  to 
the  effect  of  the  solar  rays,  the  sitter  was  obliged  to 
close  them.  Many  bold  amateurs  made  martyrs  of 
themselves  in  this  way,  but  the  result  was  not  what  their 
courage  merited.  In  1840  at  Lusset's  shop  in  the  Place 
de  la  Bourse,  might  have  been  seen  a  row  of  sad 
Belisaires,  labelled  '  photographic  portraits '  !  ^ 

The  invention  of  short -focus  object-glasses  allowed — 
in  the  execution  of  portraits — the  torment  of  the  patient 
condemned  to  absolute  immobility  to  be  reduced  to 
four  or  five  minutes.  But  it  was  still  necessary  to  sit  in 
full  sun-light.  The  model  took  a  graceful  attitude,  rest- 
ing one  hand  on  the  back  of  a  chair,  and  looking  as 
amiable  as  possible.  But  the  sun  fell  full  in  his  eyes  ! 
The  operator  gives  the  final  warning  to  keep  perfectly 
still  !  The  seconds  pass,  succeed  each  other,  and  seem 
to  expand  into  centuries ;  the  sitter,  in  spite  of  all  his 
efforts,  is  overpowered  by  the  solar  rays,  the  eyelids 
open  and  close,  his  face  contracts,  the  immobility  to 
which  he  is  constrained  becomes  a  torture.  His  features 
shrivel  up,  tears  fall  from  his  eyes,  perspiration  beads  on 
his  forehead,  he  pants  for  breath,  his  entire  body  shakes 
like  that  of  an  epileptic  who  wants  to  keep  still,  and  the 

L.  FiguUr^  les  Merveilles  de  la  Science. 


74  THE   HISTORY  OF   PHOTOGRAPHY. 

Daguerreotype  plate  represents  the  image  of  a  poor 
wretch  undergoing  all  the  tortures  of  the  ordeal  by  fire. 
Shortly  afterwards  the  discovery  of  the  accelerating  sub- 
stances permitted  Daguerreotype  portraits  to  be  taken 
with  something  of  artistic  feeling. 

It  is  not  our  purpose  to  describe  minutely  the  dif- 
ferent Daguerreotype  operations,  and  the  various  im- 
provements effected  ;  we  shall  content  ourselves  with 
noticing  only  the  discoveries  made  by  M.  Fizeau,  a 
French  experimentalist.  This  clever  operator  discovered 
the  means  of  fixing  the  Daguerreotype  picture  by  cover- 
ing it  with  a  slight  coating  of  gold.  He  arrived  at  this 
result,  as  we  have  seen,  by  pouring  a  solution  of  chloride 
of  gold  and  hyposulphite  of  soda  on  to  the  plate  and  then 
gently  heating  it.  With  this  discovery  the  complement 
of  the  processes  used  in  photography  was  completed  ;  the 
image  of  the  camera  fixed  in  a  latent  state  on  a  sensi- 
tive substance  was  made  to  appear  by  developing 
agents,  the  time  of  exposure  was  lessened,  and  the 
picture  could,  by  the  action  of  chemical  agents,  be  fixed, 
that  is  to  say,  rendered  indelible. 

Soon,  other  new  discoveries  were  to  transform,  in 
every  way,  the  art  of  Daguerre  ;  but  the  illustrious  in- 
ventor had  not  the  consolation  of  knowing  them.  He 
died  on  July  lo,  1851,  foreseeing  in  his  thoughts  the  new 


THE   PROGRESS  OF  A   NEW  ART.  75 

horizons  to  the  conquest  of  which  the  wondrous  art  he 
had  created  was  rapidly  marching. 

Whilst  Daguerre  was  carrying  on  his  researches  in 
France,  in  1834  Mr.  Talbot  in  England  was  also  en- 
deavouring to  fix  the  image  of  the  camera  ;  but  his  aim 
was  to  fix  it  on  paper.' 

This  modest  and  almost  unknown  inventor  subjected 
a  sheet  of  paper,  which  had  been  soaked  in  iodised  silver, 
to  the  action  of  light  in  the  camera ;  and  he  developed 
the  picture,  formed  as  in  the  Daguerreotype,  in  a  latent 
state,  with  gallic  acid.  The  employment  of  this  sub- 
stance was  another  great  help  to  photography. 

Talbot  was  in  the  midst  of  his  researches  when  he 
heard  of  the  publication  of  Daguerre's  invention.     He 


'  The  English  have  claimed,  but  wrongfully,  the  merit  of  the  invention 
of  photography.  Talbot's  method  was  not  practicable.  If  Talbot  kept 
silence  before  Daguerre  had  published  his  discovery,  it  was  because  he  was 
aware  of  the  imperfections  in  his  method.  Before  offering  it  to  the  public 
he  desired  to  give  it  the  certainty  and  facility  of  working  which  it  arrived 
at  in  the  hands  of  Blanquart-Evrard.  The  publication  of  the  results 
obtained  by  Niepce  and  Daguerre  established  their  titles  as  inventors  of 
photography. 

(While  I  am  at  one  with  the  author  in  according  to  Daguerre  the  full 
credit  of  the  beautiful  invention  which  bears  his  name,  yet  the  claims  of 
Talbot  can  hardly  with  justice  be  relegated  to  a  position  inferior  to  that  of 
the  famous  French  inventor.  Talbot  in  1834,  about  five  years  before 
Daguerre's  method  was  made  known  to  the  world,  had  solved  for  himself 
•the  problem  of  fixing  the  photographic  image  on  paper.  See  Abridgment 
of  Specifications,  printed  by  order  of  the  Commissioners  of  Patents  in 
England,  1854.— Ed.) 


76  THE   HISTORY   OF   PHOTOGRAPHY.    ,  • 

sent  the  results  of  his  experiments  to  France,  to  Biot, 
who  brought  them  before  the  Academy  of  Sciences.  But 
the  Daguerreotype  seemed  to  have  the  sole  right  to 
occupy  the  attention  of  Paris  ;  people  got  tired  of  the 
numberless  *  improvements '  which  were  continually 
announced,  for  the  most  part  merely  the  empty  dreams 
of  excited  and  inexperienced  minds.  Talbot's  discovery 
had  not  the  good  fortune  to  attract  the  attention  of  the 
learned  world.  It  was,  however,  estimated  at  its  true 
value  by  a  laborious  spirit,  Blanquart-Evrard,  who  cleverly 
profited  by  the  facts  made  known  by  the  experimentalist 
across  the  Channel,  and  who  soon  brought  out  an 
interesting  memoir  of  photography  on  paper.  Such  a 
result  was  anxiously  waited  for;  it  was  generally  ac- 
knowledged that  the  mirror-like  character  of  the 
Daguerreotype  plate  was  incompatible  with  a  really 
artistic  picture  ;  it  was  thought  with  reason  that  a  proof 
on  paper  would  be  softer  and  would  resemble  a  sepia 
drawing.  Thus,  as  soon  as  Blanquart-Evrard  of  Lille 
published  his  method,  his  communications  were  received 
with  expressions  of  joy  by  all  photographic  amateurs. 

Blanquart-Evrard  plunged  his  paper  in  a  sensitising 
solution ;  when  it  was  dry  he  fastened  it  between  two 
pieces  of  glass  and  so  exposed  it  in  the  camera.  These 
tiQw  manipulations,  it  must  be  admitted,  were  almost 


THE   PROGRESS   OF   A   NEW   ART.  77 

exactly  similar  to  those  employed  by  Talbot.  The  latter 
made  use  of  iodised  silver  as  a  sensitising  agent  for  pro- 
curing a  positive  proof  on  paper  ;  he  employed  chloride 
of  silver  on  the  negative  paper,  and  fixed  the  picture  by 
means  of  gallic  acid.^  He  had  the  first  idea  of  making 
a  negative  picture  to  be  used  in  the  production 
of  positive  proofs  ;  he  must  be  considered  as  the  inventor 
of  proofs  on  paper,  and  his  name  ought  to  be  inscribed 
in  the  annals  of  photography  directly  after  those 
of  Niepce  and  Daguerre. 

Blanquart-lEvrard,  profiting  by  the  interesting  studies 
of  Talbot,  contributed  to  the  improvement  of  the  photo- 
graphic art ;  he  studied  it  wholly  from  an  artistic  point 
of  view ;  he  asked  himself  what  were  the  rules  which 
should  be  observed  in  order  to  obtain  pictures  possessing 
true  harmony  and  worthy  of  being  considered  by  a 
painter.  He  found  out  ingenious  methods  of  gfving  force 
to  the  shadows,  and  of  colouring  the  positive  proof,  and 
that  by  mixing  certain  chemical  substances  with  the  re- 
agents already  in  use. 

Blanquart  at  length  was   able  to  produce  thirty  or 

'  Amongst  those  who  from  its  origin  have  contributed  to  popularise 
photography  must  be  mentioned  Bazard,  who  after  patient  researches  suc- 
ceeded in  producing  some,  for  his  time,  remarkable  photographic  proofs. 
They  were  exhibited  to  the  students  of  the  Sorbonne  University  of  Paris 
by  M.  Despretz  in  1846. 


78 


THE   HISTORY   OF   PHOTOGRAPHY. 


forty  positives  from  a  negative,  whilst  before,  two  or 
three  were  the  utmost  that  had  been  obtained.  It  would 
be  ungrateful  to  omit  his  name  in  the  history  of  the 
photographic  art.^ 

'  See  for  further  details  on  this  subject  the  Treatise  on  Photography  on 
Paper,  by  Blanquart-Evrard  (of  Lille),  Paris,  1851. 


A  list  of  some  of  the  processes  which  the  publication  of  the  discoveries 
of  Daguerre  &  Talbot  gave  rise  to  is  here  given.  Being  quite  out  of  date 
and  superseded  by  processes  subsequently  discovered,  a  detailed  description 
is  unnecessary. 

A?7iphitype.     A  paper  process  proposed  by  Sir  John  Herschel. 

Anthotype 

Calotype 

Chromatype 

Chrysotype 

Cyanotype 

Energiatype  ,,  ,,  ,,  Mr.  Hunt. 

In  another  process  for  producing  instantaneous  views,  galvanism  was  ap- 
plied, the  sensitised  plate  being  under  the  influence  of  the  fluid  when 
exposed. 


invented  and  perfected  by  Mr.  Talbot, 
in  which  chromatic  acid  was  used, 
discovered  by  Sir  John  Herschel. 


79 


CHAPTER  VII. 

PHOTOGRAPHY. 

SIR     JOHN     HERSCHEL — HYPOSULPHITE     OF    SODA — NIEPCE     DE     SAINT- 
VICTOR'S    negative    on    glass — GUN    COTTON    AND   COLLODION. 

It  is  a  remarkable  fact  in  the  history  of  great  discoveries 
that  the  inventor  himself  is  rarely  able  to  give  those 
finishing  touches  and  improvements  to  the  results  of  his 
genius  which  time  and  practice  are  sure  to  develop  in 
them.  The  mind  of  the  inventor,  however  ingenious  he 
may  be,  creates  only  slowly  and  painfully.  How  often 
has  it  not  been  the  case  that  after  supplying  some  new 
materials  to  the  edifice  of  science,  the  inventor  seems  to 
exhaust  himself,  and  has  had  to  give  up  his  task  to  other 
hands !  Many  examples  might  be  quoted  in  proof  of 
this.  Fulton,  for  instance,  started  to  the  conquest  of  the 
seas  on  a  steamboat,  rude  and  primitive  enough  :  with 
this  first  effort  his  mind  seemed  to  have  exhausted  itself ; 
one  might  say  that  his  faculties  had  not  the  gift  of  pro- 
ducing ;  they  had  invented  this  novelty,  they  were  in- 


8o  THE   HISTORY   OF   PHOTOGRAPHY. 

capable  of  promoting  its  growth  ;  it  was  reserved  for 
others  to  give  it  the  development  of  ripe  age.  Daguerre, 
after  fifteen  years  of  toil,  gave  the  world  the  Daguerreo- 
type plate,  the  first  rudiment  of  photography ;  but  here 
he  stops,  his  genius  can  carry  him  no  further. 

But  the  seed  sown  on  the  field  of  discoveries  is  culti- 
vated by  other  eminent  minds,  whose  labours  ensure  the 
fruits  of  harvest.  By  the  side  of  the  inventor  appear  a 
crowd  of  those  who,  whilst  capable  of  improving,  are 
often  incapable  of  inventing.  The  history  of  photography 
is  a  remarkable  example  of  this.  Fizeau,  Chevalier, 
Talbot,  Blanquart,  have  added  their  stones  to  the  monu- 
ment which  was  founded  by  Niepce  and  Daguerre  ;  other 
great  workers  arrived  from  time  to  time  to  contribute 
their  valuable  aid  to  the  work  of  building  ;  the  monu- 
ment grows  more  magnificent  and  grand  as  the  years 
pass  on. 

The  new  discovery  had  excited  the  admiration  of  all ; 
thQ  attention  of  the  whole  world  was  drawn  to  it.  Here 
is  the  great  Herschel,  the  illustrious  English  astronomer, 
taking  photographic  proofs ;  the  attention  of  such  a 
mind  could  not  be  directed  to  the  Daguerreotype  without 
exerting  a  salutary  influence  on  it.  He  fixed  the  image 
on  paper  by  the  method  of  which  he  had  read  the 
description ;    the  idea  occurred  to  him  of  substituting 


PHOTOGRAPHY.  8 1 


hyposulphite  of  soda  for  the  agents  until  then  employed. 
He  succeeded  beyond  all  expectation,  and  from  that  day 
the  hyposulphite  of  soda  has  been  counted  amongst 
the  most  valuable  substances  of  the  photographic 
laboratory. 

As  soon  as  Blanquart-Evrard  had  published  his  pro- 
cess of  photography  on  paper,  it  was  immediately  tried 
by  everybody,  and  the  use  of  the  silvered  plate  aban- 
doned. This  last,  it  must  be  owned,  certainly  offered 
the  advantage  of  being  practical  and  of  producing  very 
clear,  sharp  pictures,  with  extreme  fineness  of  execution 
in  the  details  ;  it  gave  proofs  of  great  delicacy  of  feature 
and  matchless  softness.  But  with  paper,  no  more  mirror- 
like reflection,  no  more  of  those  metallic  gleams  which 
only  permitted  the  picture  to  be  seen  after  inclining  it  in 
every  direction  towards  the  light. 

But  everything  has  its  good  and  its  bad  side  ;  and  the 
employment  of  paper,  it  must  not  be  disguised,  was  ac- 
companied with  more  than  one  inconvenience :  the  tex- 
ture of  the  paper  itself  was  not  very  smooth,  its  fibrous 
nature  produced  traces  and  unevennesses  which  prevented 
it  from  being  impressed  to  an  equal  extent  all  over  its 
.surface.  The  paper  was,  moreover,  too  porous,  it 
expanded  and  did  not  always  uniformly  absorb  the 
liquids  in  which  it  was  plunged  ;  the  photographic  proof 

G 


82  THE   HISTORY   OF   PHOTOGRAPHY. 

obtained  was  no  longer  characterised  by  the  same  abso- 
lute sharpness  of  line,  by  the  same  harmonious  degrada- 
tion of  light  and  shade.  To  alter  this  it  was  necessary 
to  improve  the  photographic  paper,  to  purify  its  pulp,  to 
get  rid  of  the  grain  and  irregularities  of  its  surface,  and 
to  make  it  homogeneous,  smooth,  and  as  clean  as  that  of 
the  Daguerreotype  plate. 

This  problem  was  carefully  studied  and  cleverly 
solved  by  an  experimentalist,  who  has  played  a  con- 
siderable part  in  the  history  of  photography,  Niepce  de 
Saint-Victor,  nephew  of  the  inventor  of  the  heliograph. 
He  conceived  the  happy  idea  of  having  recourse  to  glass,^ 
the  surface  of  which  is  as  smooth  and  level  as  that  of 
metal,  and  of  covering  it  with  a  slight  coating  of  a  vis- 
cous liquid,  which  possessed  the  property  of  solidifying 
and  in  which  the  impressionable  substances  could  be 
dissolved. 

To  obtain  his  negative,  Niepce  de  Saint-Victor  coated 
a  sheet  of  glass  thinly  with  albumen  (white  of  egg),  which 
formed  a  homogeneous,  smooth  surface,  extremely  well 
adapted  under  good  conditions  to  be  used  in  the  fixing  of 
the  image.      To  sensitise  this  coat  of  albumen,  the  in- 

'  Sir  John  Herschel  used  glass  plates  in  photography  as  a  support  for 
sensitive  films  in  1839.  It  is  a  curious  coincidence  that  Niepce  de  Saint- 
Victor,  some  years  later,  discovered,  independently,  the  use  of  glass  plates 
as  supports  for  his  albumen  pictures. — Ed. 


PHOTOGRAPHY.  8^ 


ventor  impregnated  it  with  iodide  of  silver,  in  the  follow- 
ing manner :  he  first  plunged  it  into  a  bath  of  iodide  of 
potassium,  and  then  into  a  solution  of  nitrate  of  silver  ; 
when  dry  the  sensitised  glass  was  ready  to  use  for  ob- 
taining a  negative  picture  at  the  focus  of  the  camera. 
The  negative,  when  fixed,  gave  paper  positives,  by  means 
of  the  processes  we  have  already  described. 

This  discovery  of  Saint- Victor's  was  of  immense 
importance  to  photography.  But  it  was  not  the  only 
help  the  photographic  art  was  to  receive  from  him,  his 
various  improvements  indeed  were  of  such  real  impor- 
tance that  we  think  it  our  duty  to  give  a  few  details 
respecting  the  clever  nephew  of  Nicephore  Niepce: 

Like  the  discoverer  of  heliography,  he  was  destined 
for  the  military  career ;  leaving  the  military  school  at 
Saumur  in  1827,  he  was  made  a  lieutenant  of  the  1st 
Dragoons  in  1842.  It  was  at  this  time  that  he  began  to 
devote  himself  especially  to  the  study  of  physics,  which 
had  always  attracted  his  eminently  scientific  mind. 

During  his  stay  at  Paris,  Abel  Niepce  de  Saint- 
Victor's  taste  for  scientific  studies  received  a  fresh  im- 
pulse. His  relative's  discovery  had  given  an  imperish- 
able glory  to  the  name,  and,  by  a  sort  of  family  feeling, 
he  seemed  to  be  drawn  into  the  pursuit  of  science.  He 
commenced    by  studying    physics  and    chemistry,  and 


84  THE   HISTORY   OF    PHOTOGRAPHY. 

turned  his  attention  particularly  to  the  investigation  of 
the  Daguerreotype  phenomena.  But  a  provincial  town 
offered  slender  resources  to  a  person  in  Niepce's  position. 
Convinced  that  the  capital  would  afford  him  greater  faci- 
lities to  carry  on  his  researches,  he  applied  to  enter  the 
Municipal  Guard  of  Paris. 

He  was  admitted  with  the  grade  of  lieutenant  in 
1845.  At  the  quarters  of  the  Paris  Municipal  Guard  in 
the  Saint-Martin  suburb,  was  a  room  belonging  to  the 
under  officer  of  police,  which  was  always  empty.  It  was 
in  this  strangest  of  laboratories  he  installed  himself 
The  camp  bed  formed  his  work  table,  and  the  shelves 
round  the  room  held  the  apparatus,  the  reagents,  and  all 
the  material  necessary  for  his  work.  It  was  a  curious 
spectacle,,  this  laboratory  in  the  midst  of  the  barracks, 
this  officer  perseveringly  prosecuting  his  scientific  studies 
in  spite  of  the  continual  calls  of  his  profession.  Our 
men  of  science  are,  usually,  more  at  their  ease  ;  they  can 
pursue  their  studies  under  the  most  favourable  conditions, 
everything  which  money  can  obtain  to  aid  them  is  at 
their  disposal ;  they  have  vast  well-stored  laboratories 
calculated  to  facilitate  their  work  ;  after  having  had 
masters  to  teach  them,  they  have  pupils  to  whom  they 
impart  their  learning.  When  success  crowns  their  efforts 
they  have  the  public,  which  applauds  their  discoveries,  the 


PHOTOGRAPHY.  85 


Academy  which  rewards  them,  and  finally  Fame  which 
smiles  upon  them.  Niepce  de  Saint-Victor  was  alone, 
as  he  was  without  a  master  so  he  was  also  without 
pupils  ;  his  budget  consisted  of  his  lieutenant's  pay  only, 
a  police  room  served  him  for  laboratory.  During  the 
day  surrounded  with  all  the  paraphernalia  of  the  savant, 
he  gave  himself  up  to  his  scientific  studies,  which  were 
constantly  being  interrupted  by  the  calls  of  his  office ; 
at  night,  with  helmet  on  head  and  sword  at  side,  he 
watched  in  silence  over  the  tranquillity  of  the  city  streets, 
endeavouring  to  chase  from  his  mind  the  thought  of  the 
work  which  was  dearest  to  his  heart. 

The  laboratory  of  this  clever  officer  was  burnt  down 
on  February  24,  1848,  but  afterwards  M.  Niepce  de 
Saint-Victor  was  enabled  to  continue  his  interesting 
studies  under  excellent  conditions,  and  other  facts  of  the 
highest  interest  in  photography  were  yet  to  be  discovered 
by  the  relative  of  the  illustrious  Nicephore  Niepce. 

In  1847,  M.  Chevreul  laid  before  the  Academy  the 
new  process  of  Niepce  de  Saint- Victor.  But  a  few  years 
later,  in  1850,  albumen  was  to  be  replaced  by  a  new 
substance,  which  offered  such  advantages  that  it  was  not 
long  in  coming  into  general  use  to  the  exclusion  of  all 
others  :  we  refer  to  collodion. 

Gun-cotton  was  discovered  in  1846  by  Schoenbein, 


86  THE   HISTORY   OF    PHOTOGRAPHY. 

who  published  it  to  the  world  of  science  principally  as  a 
fulminating  substance.  The  new  explosive  caused  uni- 
versal astonishment.  This  cotton,  apparently  different 
in  no  way  from  ordinary  cotton,  which  exploded  like 
gunpowder  on  contact  with  fire,  caused  a  veritable  stupe- 
faction ;  it  is  obtained  by  submitting  cellular  substances 
such  as  cotton  and  paper  to  the  action  of  a  mixture  of 
nitric  and  sulphuric  acid.  M.  Schoenbein's  method  was 
to  submit  carded  cotton  to  the  action  of  a  mixture 
of  these  acids.  As  often  happens  on  the  invention  of 
new  products,  gun-cotton,  which  was  to  change  the  whole 
art  of  war,  did  not  in  reality  bring  it  many  new  re- 
sources, but  it  was  to  prove  of  immense  importance 
to  photography. 

The  introduction  of  collodion  in  photography  is  due 
to  M.  Legray  ;  ^  a  pamphlet  published  by  this  clever  pho- 
tographer near  the  end  of  1856,  makes  mention  of  this 
substance,  which  Messrs.  Bingham  and  Cundell,  some 
months  later,  also  attempted  to  substitute  for  albumen. 
Shortly  after  these  experiments  were  made  known,  Scott 
Archer,  in  England,  made  collodion  the  basis  of  a  nega- 

'  It  is  well  known  that  M,  Legray  proposed  the  use  of  collodioh  in 
1850,  while  Mr.  Archer  was  prosecuting  his  independent  researches  in 
England,  but  it  is  to  the  latter  we  are  indebted  for  the  first  practical  details 
of  a  collodion  process  piiblished  in  i8'5i, — Ed. 

[See  also  Mr,  Archer's  letters  to  the  Athencrnin^  in  January  1852,  and 
his  Manual  of  the  Collodion  Photographic  Process,  published  March  1852.] 


PHOTOGRAPHY.  S"; 


tive  process  remarkable  for  its  clearness  and  finish.  It 
is  this  process,  improved  and  perfected  from  time  to  time, 
which  for  more  than  twenty  years  has  been  the  basis  of 
nearly  every  photographic  operation.  Its  principle  is 
simple,  thus  :  gun-cotton  is  dissolved  in  a  mixture  of 
alcohol  and  ether,  and  the  collodion  obtained,  with  the 
addition  of  iodides,  and  sometimes  of  soluble  bromides, 
is  poured  on  a  glass  plate.  As  soon  as  it  has  set 
through  evaporation,  it  is  plunged  in  a  bath  of  nitrate  of 
silver  in  order  to  impregnate  it  with  iodide  and  bromide 
of  silver.  Charged  with  these  insoluble  compositions, 
and  covered  still  with  free  nitrate  of  silver,  the  plate  is 
exposed  for  a  few  seconds  to  the  action  of  light  in  the 
camera.  It  is  then  removed  to  a  dark  room  and  sub- 
mitted to  the  action  of  reducing  agents  to  complete  the 
decomposition  which  the  light  has  commenced,  and 
transform  the  latent  image  into  a  visible  and  negative 
picture.  Sulphate  of  iron  and  pyrogallic  acid  are  chiefly 
employed  to  produce  this  effect. 

After  development  the  picture  or  image  is  Jixed, 
that  is  to  say,  deprived  of  the  unaffected  and  still  sensi- 
tive salts  by  means  of  hyposulphite  of  soda  or  cyanide 
of  potassium.  From  a  negative  thus  obtained  any 
number  of  positive  pictures  on  paper  may  be  taken  by 


88  THE    HISTORY   OF   PHOTOGRAPHY. 

exposing  paper  sensitised  with  silver — placed  under  and 
in  contact  with  the  negative — to  the  action  of  light. 

On  the  appearance  of  collodion  the  art  of  photo- 
graphy may  be  said  to  have  been  completed.  We  there- 
fore close  its  history  at  that  epoch. 


PART    II. 

THE  OPERATIONS  AND  PROCESSES  OF 
PHOTOGRAPHY. 


CHAPTER   I. 

THE   STUDIO   AND   APPARATUS. 

ARRANGEMENT  OF  A  GOOD  STUDIO— THE  DARK  ROOM — TERRACE- 
SITTING  ROOM — THE  INFLUENCE  OF  LIGHT — ARRANGEMENTS  FOR 
LIGHTING  THE  OBJECT  TO  BE  PHOTOGRAPHED— THE  APPARATUS — 
LENSES   AND   CAMERAS. 

The  photographic  studio  should  consist  of  a  room  in 
which  the  camera  and  photographic  accessories  may  be 
freely  used,  and  of  a  dark  room.     It  is  necessary  that 

[In  the  Appendix  the  reader  will  find  some  formulae  in  general  use  for 
obtaining  negatives  and  printing  positives  on  paper  by  the  ordinary  '  Wet 
Plate  Process'  as  it  is  called,  in  contradistinction  to  the  'Dry  Plate  Pro- 
cess,' which  is  referred  to  farther  on.  By  the  Dry  Process  excellent  results 
are  to  be  obtained,  but  for  general  work  the  Wet  Process  is  greatly  to  be 
preferred.  But  whichever  process  is  employed,  to  get  good  results,  it  is  a 
sine  qua  non  that  the  chemicals  used  are  of  the  best  quality.  The  beginner 
will  find  it  most  economical  to  prepare  all  the  mixtures  himself,  with  the 
exception  of  the  collodion.  Before  purchasing  the  more  expensive  pho- 
tographic tnateriel,  such  as  cameras  or  lenses,  he  would  do  well  to  get  the 
advice  of  some  friend  acquainted  with  the  subject.] 


90   OPERATIONS  AND  PROCESSES  OF  PHOTOGRAPHY. 

the  latter  should  not  be  absolutely  dark,  as  various 
manipulations  have  to  be  conducted  in  it ;  it  may  be 
lightened  by  means  of  a  window  with  yellow  glass  or  a 
yellow  blind,  or  even  by  a  lamp  with  a  yellow  shade  (the 
yellow  decomposes  the  light,  allowing  only  the  non- 
actinic  or  non-sensitive  rays  to  pass  through). 

That  part  of  the  studio  set  apart  for  work  not  re- 
quiring protection  from  daylight  needs  no  special  de- 
scription. It  should  have  shelves  arranged  around  its 
walls  for  holding  bottles  of  chemicals,  &c.  ;  a  work-table 
for  cleaning  glasses  on,  and  a  pair  of  scales  are  the  prin- 
cipal necessaries. 

The  dark  room  should  be  arranged  with  the  greatest 
care  ;  in  it  the  sensitive  plates  are  prepared,  and  the 
various  delicate  processes  which  have  to  be  guarded  from 
daylight  are  performed.  We  have  said  that  every  ray 
of  white  light  must  be  carefully  excluded.  It  should  be 
conveniently  arranged,  so  that  the  operator  has  ready 
at  hand  all  the  things  he  requires  when  manipulating, 
which  he  has  to  do  as  quickly  as  possible.  {Fig..io.)  A 
narrow  table  is  fixed  to  the  wall  for  supporting  the  sen- 
sitising baths,  which  have  to  be  placed  in  a  somewhat 
inclined  position.  There  should  be  a  row  of  shelves  for 
holding  the  bottles  of  collodion  and  other  chemicals.  It 
is  well  to  have  a  sink  near  the  table  with  a  tap  above  it 


Fig.  io 
the  dark  room. 


[Page  90 


THE  STUDIO   AND   APPARATUS.  QI 

for  washing  the  proofs  ;  this  tap  may  be  advantageously 
fitted  with  a  piece  of  indiarubber  tubing  having  a  rose 
at  the  end  so  that  the  water  may  be  quickly  and  easily 
applied  over  a  large  surface. 

A  terrace  well  exposed  to  daylight  is  also  necessary 
for  exposing  the  printing  frames  containing  the  nega- 
tives to  be  reproduced  on  paper.  If  possible,  there 
should  be  a  second  dark  room  placed  near  this  terrace 
for  the  preparation  of  the  photographic  paper  for  taking 
positives. 

The  room  in  which  the  sitter  is  placed  is  the  most 
important  part  of  a  good  photographic  establishment : 
it  should  be  constructed  in  a  position  very  accessible  to 
the  light,  and  lighted  in  a  special  manner.  The  mode 
of  distributing  the  light  in  the  posing  room  contributes 
to  give  the  pictures  produced  that  harmony  which  cha- 
racterises really  artistic  photographs. 

If  the  sitting  room  is  only  lightened  by  horizontal  win- 
dows placed  on  one  side,  or  if  it  receives  light  from  all 
sides  at  once,  the  effect  of  the  too  strong  or  too  feeble 
light  thus  obtained  is  equally  prejudicial  to  obtaining 
good  pictures. 

The  first  condition  in  a  good  posing  room  is  that  it 
should  face  the  north ;  if  it  is  placed  at  the  top  of  a 
house  it  should  be  glazed  on  one  side  and  on  the  roof  like 


92        OPERATIONS   AND    PROCESSES   OF   PHOTOGRAPHY. 

a  conservatory — glass  of  a  clear  blue,^  coloured  with  co- 
balt, should  be  chosen  in  preference  to  all  other  sorts ;  it 
has  the  property  of  sifting  the  light,  allowing  the  chemical 
rays  to  pass,  and  producing  a  soft  and  harmonious  effect. 
The  side  window  and  glass  roof  should  be  provided  with 
large  blue  blinds  capable  of  being  easily  drawn  across 
any  part  where  it  may  be  necessary  to  intercept  the  light. 
To  these  preliminary  precautions  should  be  added  others, 
which  are  particularly  recommended  by  Mr.  Liebert,  an 
expert  photographer. 

'  Cleanness  of  the  glass,'  says  this  clever  experi- 
mentalist,^ ^  is  likewise  of  great  importance  in  regard  to 
the  rapidity  of  operations.  The  windows  should  be 
cleaned  as  often  as  necessary,  so  that  the  light  may  pro- 
duce its  maximum  of  rapidity.  In  order  to  soften  and 
modify  the  effect  of  the  intense  glare  on  the  eyes,  the 
interior  walls  should  be  painted  blue  or  light  grey  ; 
green,  yellow  or  red  colours  should  be  excluded  from  the 
room  as  giving  unfavourable  reflections.' 

We  subjoin  some  further  hints  from  M.  Liebert, 
which  will  be  found  useful  in  the  employment  of  light 

'  Blue  glass  used  to  be  greatly  in  vogue,  but  the  pure  homogeneous  blue 
which  admits  only  the  most  actenic  rays  of  the  solar  spectrum  is  so  difficult  to 
obtain  that  its  use  has  been  for  the  most  part  abandoned  in  England.  A 
skilful  photographer,  with  the  aid  of  a  well-devised  set  of  blinds  and  white 
glass,  may  manipulate  the  light  so  as  to  produce  any  effect  he  may  desire. — Ed. 

2  La  Photographie  en  Amerique.    Paris,  1864. 


THE   STUDIO   AND   APPARATUS.  93 

for  photography.  *  The  chemical  action  of  light  varies 
considerably,  according  to  the  state  of  the  atmosphere  ; 
on  a  bright,  clear  day  it  is  more  rapid  than  in  dull, 
gloomy  weather.  The  light,  in  order  to  act  on  the 
chemical  substances  employed  to  form  the  photographic 
picture,  should  be  white.  Gas-light,  candle-light,  even 
the  light  of  the  sun  passed  through  a  yellow  glass,  has 
hardly  any  effect  on  the  nitrate  of  silver  The  electric 
light,  magnesium  light,  and  daylight  darken  it. 

*  All  colours  are  not  reproduced  with  equal  rapidity  ; 
thus  black,  red,  yellow,  and  green  take  much  longer  to 
impress  themselves  than  white,  blue,  lilac,  and  rose.  The 
colours  of  the  object  to  be  photographed  must  therefore 
be  taken  into  account  in  regulating  the  duration  of 
exposure.' 

For  out-of-door  views  the  most  favourable  conditions 
are  those  which  place  the  different  points  of  the  land- 
scape to  be  reproduced  in  a  light  of  a  nearly  even  in- 
tensity throughout,  when  the  sun,  approaching  the  zenith, 
projects  the  light  from  above,  because  the  shadows  are 
then  least  considerable.  The  light  of  sunrise  and  sunset, 
which  produces  such  beautiful  effects  in  Nature,  is  not 
so  well  adapted  for  photography,  by  reason  of  the  feeble 
photogenic  colours  which  are  reflected  in  red  or  yellow, 
over  the  whole  landscape.     Nevertheless,  certain  pictorial 


94   OPERATIONS  AND  PROCESSES  OF  PHOTOGRAPHY. 

effects  may  be  obtained  by  a  photographer  who  is  master 
of  his  art,  when,  soon  after  sunrise,  or  just  before  sunset, 
long  transparent  shadows  veil  the  landscape.  The  time 
should  therefore  be  chosen  by  the  amateur  when  the  sun, 
being  at  its  highest  lustre,  is  in  the  greatest  possible 
harmony  with  the  sky,  in  order  that  the  objects  in  the 


PHOTOGRAPHIC    BELLOWS   CAMERA. 


view  should  produce  an  almost  equal  impression  in  the 
camera  ;  the  effect  of  solarisation  is  thus  avoided. 

The  apparatus  with  which  photographs  are  taken, 
and  which  takes  the  place  of  the  dark  room,  is  called  the 
camera  ;  ^  it  consists  of  a  plain  or  bellows  box,  at  the 
back   of  which  is    a  movable   frame  of  ground    glass. 


•  In  the  Appendix  will  be  found  an  illustrated  description  of  a  'rotating 
camera,'  for  taking  panoramic  views,  &c. 


THE   STUDIO  AND  APPARATUS.  95 

The  front  is  furnished  with  a  brass  tube  (fig.   ii)%  con- 
taining the  lens. 

The  lens  is  the  soul  of  photography.  It  should  be 
constructed  in  the  best  manner  possible  by  means  of 
glasses  thoroughly  achromatised. 

'  Everybody  knows  that  the  lens  as  it  is  used  in  the 
ordinary  camera  is  a  convergent  glass,  giving  a  reduced 
and  an  inverted  image  of  exterior  objects.  This  image 
is  projected  on  to  the  ground  focussing  glass,  which  is 
placed  at  the  back  of  the  camera.  It  is  hardly  necessary 
to  say  that  the  size  of  the  picture  thus  formed  de- 
pends on  the  size  of  the  lens  and  the  distance  from  the 
object. 

There  are  two  sorts  of  lenses  used  in  photography  : 
the  simple  lens  and  the  compound  lens.  The  first  is  prin- 
cipally used  for  landscapes  :  it  is  constructed  in  such  a 
manner  as  to  give  to  all  parts  of  the  picture  the  same 
character  of  fineness,  sharpness,  and  exactitude.  The 
second  is  chiefly  employed  for  the  execution  of  portraits  ; 
the  greater  convexity  of  its  glasses  throws  a  very 
luminous  image  on  the  centre  of  the  plate,  though 
becoming  less  so  as  its  edges  are  approached,  thus 
enabling  the  operator  to  obtain  a  picture  almost  instan- 
taneously. 

The  single  lens  consists  of  two  glasses,  the  one  con- 


96        OPERATIONS   AND   PROCESSES   OF   PPIOTOGRAPHY. 

cave,  which  fits  into  the  convexity  of  the  other.  This 
system  of  two  glasses  thus  forms  a  single  achromatic 
lens,  the  object  of  which  is  to  destroy  the  coloured  fringe 
which  appears  round  the  edges  of  non-achromatised 
glasses,  and  to  render  the  foci  of  the  different  coloured 
rays  of  light  coincident.  The  double  or  compound  lens 
consists  of  the  single  achromatic  lens  with  the  addition 
of  two  other  glasses,  the  first  convergent,  and  the  second 


Fig.  12. 


THE   LENS,   WITH   ITS   RACKWORK   AND   CAP. 

concavo-convex.  With  the  compound  lens  on  a  bright 
day,  it  is  possible  to  obtain  a  photograph  in  one  or  two 
seconds;  it  is  therefore  employed,  as  we  have  already 
said,  for  taking  portraits.  Lenses  are  also  made  which 
can  be  used  either  for  portrait  or  landscape  work  ;  in 
every  case  the  lens-tube  is  furnished  with  a  diaphragm,^ 

'  In  Fig.  1 7  the  diaphragm  is  the  piece  of  metal  with  circular  opening 
in  the  centre  in  the  slit  of  the  lens  tube  ;  when  pushed  down  into  its  place 
between  the  glasses  the  amount  of  light  admitted  into  the  camera  is  regu- 
lated by  the  size  of  its  aperture. 


THE   STUDIO   AND   APPARATUS. 


97 


the  object  of  which  is  to  confer  sharpness  on  the 
image  which  would  otherwise  be  indistinct ;  it  is  mova- 
ble and  can  be  used  of  various  sizes,  according  to  cir- 
cumstances.    The  camera  is  also  provided  with  a  small 

Fig.  13. 


SIMPLE   PHOTOGRAPHIC    APPARATUS. 


pinion  which  works  in  a  line  of  teeth  on  the  inner 
movable  brass  tube  containing  the  lenses,  by  means 
of  which  the  focus  may  be  adjusted  wi^h  the  greatest 
nicety. 

Fig.    12    represents  the   brass   tube   containing   the 
lens ;  the  milled  head  and  rackwork  are  seen  on  the  top 

H 


98   OPERATIONS  AND  PROCESSES  OF  PHOTOGRAPHY. 


of  the  tube ;  and  the  remaining  piece  is  the  cap  for  ex- 
cluding light. 

The  lens  tube  fixes  on  to  the  camera  by  means  of  a 
screw  which  works  in  a  metal  worm  fixed  to  the  camera. 
The  body  of  the  camera  is  formed  of  two  distinct  parts, 
sliding  one  into  another  in  such  a  way  that  the  operator 
can  at  will  vary  the  distance  which  separates  the  lens 
from  the  focussing  glass.  This  mobility  of  the  focussing 
glass  has  been  realised  in  a  very  simple  practical  manner, 
on  the  bellows  principle,  combined  with  a  hinge,  by 
means  of  which  the  focussing  glass  and  the  dark  slide 
can  be  placed  in  all  the  positions  necessary  in  the  various 
conditions  of  taking  a  photographic  picture. 

Fig.  1 1  represents  a  bellows  camera  with  hinge  which 
is  light  and  very  portable,  and  can  be  shut  up  into  a 
very  small  space. 

In  the  majority  of  cases,  very  good  results  can  be 
obtained  with  a  camera  formed  as  shown  in  fig.  13,  with- 
out bellows.  The  two  parts  of 
this  camera  are  made  of  wood, 
and  represented  by  M  and  N. 
A  and  B  are  the  tubes  contain- 
ing the  lenses  movable  by 
means  of  the  pinion  V  which 
'^'  ^^'  turns  the  rackwork.      The  cap 

is  shown  a  little  above  the  lens  tube.     The  frame  con- 


THE   STUDIO   AND   APPARATUS. 


99 


taining  the  focussing  ground  glass  marked  G  works  in  a 
groove,  into  which  also  fits  the  dark  slide  (see fig.  14),  con- 
taining the  plate  to  be  exposed.     When  the  focus   has 


Fig.  15- 


THE   CAMERA   STAND. 


been  obtained  on  the  ground  glass  the  latter  is  drawn  out, 
and  the  dark  slide  containing  the  sensitised  plate  slipped 
into  its  place,   so  that  when  it  is  exposed  to  the  light 


lOO     OPERATIONS   AND    PROCESSES   OF   PHOTOGRAPHY. 

exactly  the  same  picture  is  thrown  upon  it  as  on  the 
ground  glass.  A  section  of  the  lens  arrangement  used  in 
this  camera  is  shown  in  fig.  14.  A  is  the  fixed  tube  ;  B  the 
sliding  tube  which  is  enclosed  by  the  former,  and  which 
allows  the  two  systems  of  glasses  at  E  and  D  to  be  moved. 
The  object  of  the  lens,  as  we  have  explained,  is  to 


'ig.   16. 


THE    DARK   SLIDE. 


project  a  picture  of  exterior  objects  on  to  a  screen 
placed  at  the  back  of  the  camera.  This  screen  consists 
of  a  sheet  of  ground  glass  ;  to  examine  the  picture,  which 
is  reversed,  the  operator  has  to  exclude  as  much  light  as 
possible  from  it,  and  for  this  purpose  places  a  dark  cloth 
over  his  head  and  shoulders  ;  but  this  is  a  manoeuvre  too 
well  known  to  need  description. 


THE   STUDIO   AND   APPARATUS,  lOI 

Fig.  1 5  represents  a  camera  stand,  by  means  of  which 
the  camera  can  be  raised  or  lowered  or  fixed  at  any  in- 
clination desired.  This  is  done  by  the  aid  of  a  comph- 
cated  arrangement  of  screws  as  shown  in  our  illustra- 
tion. 

To  expose   the  sensitised  plate   in  the   camera,  it  is 


TWIN-LENS    CAMERA,   SHOWING    DARK    SLIDE    AND    DIAPHRAGMS. 

fixed  in  a  frame  called  the  dark  slide,  which,  as  before 
mentioned,  fits  into  the  camera  in  the  same  plane  as  the 
focussing  glass. 

The  dark  slide  is  shown  in  fig.  i6  ;  it  is  made  up  of 
a  frame  forming  a  box.  At  the  back  of  the  frame  is  a 
door  which  opens  and  shuts.  The  sensitised  plate  on 
being  removed  from  the  bath  in  the  dark  room  is  placed 


102     OPERATIONS   AND    PROCESSES   OF   PHOTOGRAPHY. 

in  the  dark  slide,  film  side  inwards,  and  the  door  being 
shut,  a  spring,  as  shown  in  the  illustration,  presses 
against  the  uncoated  surface  of  the  glass,  and  holds  it 
firmly  in  its  place.  On  the  front  of  the  dark  slide 
is  another  door,  also  made  of  wood,  which  slides  in  a 
groove,  and  when  it  is  lifted  up  in  the  camera,  until  it 
can  be  turned  over  on  hinges  as  shown  in  the  drawing, 
the  light  of  course  falls  on  the  sensitised  surface  of  the 
plate  as  soon  as  the  lens  cap  is  removed.  On  the  other 
hand,  when  it  and  the  other  door  are  both  shut  they 
keep  the  plate  in  perfect  darkness,  and  thus  permit  the 
operator  to  carry  it  from  the  dark  room  to  the  camera 
and  vice  versa. 

Figure  17  represents  the  different  positions  of  the 
dark  slide  before  commencing  operations.  It  shows  at 
the  same  time  the  general  appearance  of  a  good  twin  lens 
camera.  The  photographer  has  examined  on  the 
ground  glass  the  picture  to  be  reproduced ;  he  has 
obtained  the  necessary  distinctness  or  sharpness  by 
moving  the  brass  tube  containing  the  lens  by  means  of 
the  pinion  ;  he  has,  in  fact,  focussed  the  picture,  that  is  to 
say 'found,  by  trial,  the  optical  focus  point,  the  only  point 
at  which  the  picture  presents  perfect  sharpness.  He  can 
now  place  the  sensitised  plate  at  this  focus.  He  carries 
it  in  its  dark  slide,  and  after  removing  the  ground  glass. 


THE   STUDIO   AND   APPARATUS. 


103 


carefully  slides  it  into  its  place. 
He  now  pulls  out  the  movable 
door,  and  the  plate  is  then  only 
protected  from  the  light  by  the 
brass  cap  on  the  lens  tube.  He 
gives  a  last  caution  to  the 
sitter  to  'keep  quite  still,'  re- 
moves the  cap,  and  instantly 
the  picture  of  the  sitter  im- 
prints itself  on  the  sensitive 
film.  The  cap  is  replaced,  the 
sliding  door  again  pushed 
down,  and  the  plate  in  its 
slide  removed  to  the  dark  room 
to  be  developed,  intensified  if 
necessary,  and  lastly  fixed,  as 
will  be  explained  farther  on. 

We  shall  have  occasion  to 
describe  a  great  variety  of 
other  apparatus  employed  in 
photography  in  the  course  of 
our  account  of  the  different 
processes  and  methods  which 
require  their  use.  We  shall, 
however,  close  this  chapter  "^^ 
with    a    short     description    of 


Fig.  18. 


THE   HEAD-REST. 


104     OPERATIONS   AND   PROCESSES   OF    PHOTOGRAPHY. 

the  head-rest  represented  in  fig.  i8,  an  instrument 
which  no  portrait  studio  should  be  without.  There 
are  very  few  persons  who  can  keep  perfectly  still,  even 
for  a  few  seconds.  Their  heads  move  without  their 
being  aware  of  it.  They  should,  therefore,  after  taking 
graceful  pose  be  supported  by  resting  the  head  in  the 
half-circle  of  the  head-rest. 

In  adjusting  the  latter  care  should  be  taken  that  the 
position  of  the  sitter  is  not  altered,  otherwise  it  will  very 
often  happen  that  a  most  objectionable  stiffness  is  im- 
parted to  the  patient,  and  a  caricature  rather  than  a  por- 
trait is  the  result. 


I05 


CHAPTER   II. 

THE   NEGATIVE. 

MANIPULATION  OF  THE  PHOTOGRAPH — CLEANING  THE  PLATE— COATING 
THE  PLATE  WITH  COLLODION— PLACING  IT  IN  THE  SILVER  BATH  — 
EXPOSURE  IN  THE  CAMERA — DEVELOPMENT,FIXING,  AND  VARNISHING. 

Having  thus  got  ready  our  studio,  and  the  most  neces- 
sary apparatus,  we  shall  proceed  to  describe  the  delicate 
manipulations  required  to  obtain  a  good  photograph. 

Cleaning  the  Plate. — After  carefully  selecting  a 
number  of  glass  plates  of  the  required  size,  free  from 
scratches,  air-bubbles,  or  stains,  and  perfectly  flat,  the 
next  process  is  to  clean  them.  This  operation  does  not 
consist,  as  might  be  supposed,  in  simply  rubbing  them 
with  a  cloth,  but  is  much  more  minute  ^nd  delicate.  The 
plate  is  placed  in  a  plate-holder  (fig.  19),  a  wooden 
frame  provided  with  a  screw  vice  by  means  of  which  the 
glass  can  be  held  firmly  without  its  being  necessary  to 
touch  it  with  the  fingers.  The  slightest  contact  with  the 
hand,  always  a  little  greasy,  is  sufficient  to  prevent  the 
perfect  adhesion  of  the  collodion.  A  plate-cleaning  paste 


I06     OPERATIONS   AND   PROCESSES   OF    PHOTOGRAPHY. 

is  now  made  by  mixing  Tripoli  powder  and  alcohol  in  a 
bottle.  After  shaking  the  bottle  well,  a  little  of  the 
mixture  is  poured  on  to  a  piece  of  flannel,  and  the  plate 
well  rubbed  with  it.  It  is  next  dried  with  filtering  paper, 
or,  better  still,  with  a  paper  of  great  delicacy  called 
Japanese  paper.  In  winter  it  is  well  to  heat  the  plates 
slightly,  to  get  rid  of  the  humidity  caused  by  the  pre- 


Fig.  19. 


ni 


PLATE-HOLDER. 


cipitation  of  moisture  from  the  warmer  atmosphere.  We 
cannot  insist  too  strongly  on  the  extreme  importance  of 
perfectly  clean  plates  ;  if  sufficient  care  is  not  taken  in 
this  respect,  the  success  of  the  operation  is  at  once  com- 
promised. 

Collodion,  its  preparation. — Collodion  is  a  thick  trans- 
parent liquid,  which  possesses  the  property  of  solidifying 
when  exposed  to  the  air.  It  is  made  by  dissolving  gun- 
cotton  in  a  mixture  of  alcohol  and  ether.     Although  it 


THE   NEGATIVE.  10/ 

is  easy  to  procure  good  collodion  ready  made,  we  think 
it  may  be  useful  if  we  give  the  method  of  making  it.^ 

Coating  the  plate  with  Collodion. — The  collodion  being 
thus  obtained  and  ready  to  our  hand  in  the  dark  room, 
we  will  proceed  to  describe  the  process  of  taking  a  pho- 
tographic negative. 

•  Mix  one  part  of  dry  pulverised  nitrate  of  potash  with  three  parts  of 
concentrated  sulphuric  acid  in  a  porcelain  capsule,  the  nitrate  of  potash  being 
put  in  first,  and  the  sulphuric  acid  slowly  added  little  by  little.  The 
mixture  must  be  constantly  stirred  with  a  glass  rod.  It  is  then  gently  warmed 
to  a  heat  of  60°  centesiviaux,  ascertained  by  the  mercurial  thennometer. 
This  may  be  done  by  adding  water  to  the  mixture,  the  quantity  depending 
on  the  specific  gravity  of  the  acid.  The  cotton,  which  should  be  of  good 
quality,  well  carded,  very  fine  and  clean,  is  now  immersed  in  the  mixture 
and  well  stiiTed  and  moved  about  with  a  glass  spoon,  so  as  to  soak  it  well 
all  through.  It  is  left  in  contact  with  the  sulphuric  acid  for  the  space  of 
two  hours,  and  is  then  well  washed.  It  only  remains  to  diy  it  and  the 
gun-cotton  is  made. 

To  test  the  quality  of  the  gun-cotton  a  little  of  it  is  ignited  ;  it  should 
burn  very  rapidly,  without  leaving  any  black  residue. 

The  gun-cotton  thus  prepared  is  now  dissolved  in  a  mixture  of  alcohol 
and  ether  in  the  following  proportions  for  plain  negative  collodion  : — 

Alcohol,  sp.  gr.  725 2\  fluid  ounces. 

Sulphuric  Ether,  sp.  gr.  -805       .         .         .          5         ,,        ,, 

Sixty  grains  of  gun-cotton  can  be  dissolved  in  the  above  quantity  of 
alcohol  and  ether.  The  alcohol  is  first  poured  into  a  large-necked  glass 
bottle  with  ground-glass  stopper.  The  gun-cotton  is  next  introduced,  and 
the  bottle  well  shaken  in  order  to  thoroughly  soak  it.  Lastly  the  sulphuric 
ether  is  added,  and  the  whole  well  shaken  again  until  all  the  cotton  is 
dissolved.  A  viscous  syrupy  liquid  is  thus  obtained  ;  it  should  be  allowed 
to  stand  for  forty-eight  hours,  and  then  decanted  into  a  clean  dry  bottle,  in 
which  it  can  be  kept  until  required  to  be  sensitised. 

To  sensitise  the  collodion  it  is  necessary  to  add  certain  chemical  agents 
which,  combined  with  the  nitrate  of  silver,  form  a  solution  sensitive  to  light. 


I08     OPERATIONS  AND   PROCESSES   OF   PHOTOGRAPHY. 

The  plate,  which  has  been  cleaned  with  the  greatest 
care,  has  now  to  be  covered  with  a  slight  coating  of  sen- 
sitised collodion.  This  operation  of  pouring  on  the 
collodion  is  a  somewhat  delicate  one,  and  requires  a  little 
skill  and  practice.  The  plate  is  held  by  one  of  the 
corners  in  a  horizontal  position  between  the  thumb  and 
forefinger  ;  taking  the  collodion  bottle  in  the  other  hand 
a  small  quantity,  sufficient  when  spread  out  to  cover  the 
plate   (fig.  20),  is  poured  gently  on  to  the  middle.      By 


Various  substances  are  employed  for  this  purpose,  but  the  iodides  and 
bromides  are  chiefly  used.  The  following  alcoholic  solution  is  recommended 
by  Mr.  A.  Liebert  for  sensitising  collodion  : — 

ns.  (Eng.) 


Iodide  of  Potassium     . 

330  grai 

Bromide  of  Potassium 

120        , 

Iodide  of  Ammonium  . 

270       , 

Bromide  of  Ammonium 

150        , 

Iodide  of  Cadmium    .         . 

300        , 

Bromide  of  Cadmium 

150        , 

Iodide  of  Zinc 

180        , 

Alcohol  of  40**  .         .         .          . 

if  Imp.  Pint  =  35  oz. 

The  recipes  for  making  sensitised  collodion  vary  to  an  almost  infinite 
extent,  and  we  cannot  pretend  to  give  a  list  of  formulas,  which  woidd  take 
us  too  far  out  of  our  way,  and  give  the  book  too  much  the  form  of  a 
treatise.  We  repeat  that  amateurs,  and  even  photographers  themselves, 
are  in  the  habit  of  procuring  their  collodion  ready  sensitised  of  good 
makers.  The  methods  we  give  are  chiefly  to  enable  the  reader  to  under- 
stand the  simple  operations  of  photography. 

[I  need  hardly  add  that  it  would  be  unwise  for  the  amateur  who  has 
not  made  himself  thoroughly  acquainted  with  the  chemistry  of  the  operation 
to  attempt  to  make  his  own  collodion,  as  he  would  encounter  a  number  of 
technical  difficulties  which  can  only  be  overcome  by  those  who  have  made 
the  manufacture  of  collodion  their  special  study.— Ei).] 


THE   NEGATIVE. 


09 


inclining  the  plate  the  liquid  is  made  to  flow  first  to  the 
corner  where  the  glass  is  held,  avoiding  contact  with  the 

Fig.  20. 


COATING  THE   PLATE.       FIRST   POSITION   OF    THE   HANDS. 


Fig.   21 


SecOKD   POSITION   OF   THE  HAND.'?, 


thumb,  then  to  the  top  left-hand  corner,  then  to  the  right 


no     OPERATIONS   AND   PROCESSES   OF   PHOTOGRAPHY. 

one,  and  lastly  the  surplus  is  poured  back  into  the  collo- 
dion bottle  from  the  remaining  corner  (fig.  21).'  Care 
must  be  taken  that  the  collodion  does  not  flow  twice  over 
the  same  spot,  or,  instead  of  being  level,  the  surface  will 
present  unevennesses  which  will  prove  injurious  to  the 
development  of  the  image.  In  order  not  to  waste  un- 
necessarily so  expensive  a  substance  as  collodion,  the 
beginner  should  get  his  hand  in  a  little  by  practising 
with  gum-water  of  a  similar  consistency.  When  the 
plate  is  coated  and  found  to  be  free  from  streaks, 
points  or  blurs  of  any  sort,  and  clear  and  trans- 
parent, it  is  allowed  a  few  seconds  to  set  by  evaporation, 
it  is  then  ready  for  immersion  in  the  silver  bath. 

The  sensitising  silver  bath  for  negatives  may  be 
made  as  follows  : — 

Recrystallised  neutral  Nitrate  of  Silver   .          .  350  grains. 

Distilled  Water 10  fluid  ounces. 

Glacial  Acetic  Acid i  drop. 

Iodide  of  Potassium i  grain. 

Dissolve  and  filter. 

The  bath  for  positives  should  be  of  40  grains  silver  to 
the  ounce  of  water. 

Immersion  in  the  sensitising  bath. — The  operation  of 
plunging  the  plate  into  the  silver  bath  must  be  performed 

^  Whilst  the  surplus  liquid  is  running  off  into  the  bottle,  and  until  it 
sets,  which  will  be  almost  directly,  the  plate  must  be  moved  backrt'ards 
and  forwards,  or  ridges  will  form  on  the  film. 


THE   NEGATIVE. 


Ill 


rapidly  without  stopping,  in  order  that  the  collodion  film 
may  be  brought  into  contact  with  the  liquid  over  its 

Fig.   22. 


SENSITISING   TRAY. 


whole  surface  at  the  same  moment.  The 
dish  containing  the  bath  is  tilted  a  little, 
so  that  the  liquid  collects  at  one  end  ;  the 
edge  of  the  plate  is  then  placed  (see  fig.  22) 
against  the  other  end,  and  by  means  of  a 
silver  hook  lowered  into  the  liquid,  the 
dish  being  brought  back  to  the  horizontal 
position  at  the  same  time  ;  by  this  means 
the  silver  is  made  to  flow  evenly  over  the 
whole  surface.     The  plate  is  allowed  to 


Fig.  23. 


SILVER  HOOK  FOR 
RAISI.NG  AND  LOW- 
ERING THE  PLATE. 


112     OPERATIONS   AND    PROCESSES    OF    PHOTOGRAPHY. 

remain  for  a  few  seconds  in  the  bath  and  then  examined 
by  raising  one  end  with  the  hook  ;  it  should  present  a 
smooth,  clear  surface  of  an  opaline  tint ;  should  this  not 
be  the  case,  and   the  plate  have  a  greasy  appearance, 

Fig.  24. 


GLASS  BATH   IN  CASE  WITH   GLASS   DIPPER. 


it  must  be  allowed  to  remain  a  little  longer  in  the 
bath.  Gently  raising  the  plate  in  and  out  of  the 
liquid  accelerates  the  action  of  the  silver. 

Fig.  24  represents  another  and  very  convenient  form 
of  bath,  usually  made  of  glass  ;  its  interior  sides  are 


THE  NEGATIVE.  II3 


concave,  so  that  when  the  plate  is  slid  in  by  means  of  a 
glass  or  other  dipper,  only  its  edges  come  in  contact  with 
the  sides  of  the  bath,  the  film  being  thus  protected  from 
scratches.  Though  this  form  of  bath  requires  a  larger 
quantity  of  the  silver  solution,  it  has  nevertheless  the 
advantage  of  being  much  more  slowly  exhausted,  and 
can  be  protected  from  dust  even  when  in  use  by  means 
of  a  cap  fitting  on  to  the  top. 

The  plate  thus  prepared  is  placed  in  the  dark  slide 
and  kept  in  a  perpendicular  position,  and  is  now  ready  for 
exposure  in  the  camera. 

Exposure  in  the  camera. — It  is  impossible  to  give 
any  definite  rule  as  to  the  time  the  plate  should  be  ex- 
posed in  the  camera  ;  the  power  of  the  lens,  amount  of 
light,  quality  of  the  collodion,  colours  of  the  object  to  be 
reproduced,  &c.,  have  all  to  be  taken  into  consideration. 
Practice  can  alone  guide  the  photographer. 

In  the  studio  the  time  of  exposure  varies  from  three 
to  thirty  seconds.  For  landscapes  the  plate  should  be 
exposed  in  accordance  with  the  nature  of  the  collodion, 
the  developer  used,  &c. 

The  amateur  should  accustom  himself  to  count  the 
seconds  mentally,  instead  of  always  having  to  rely  on  a 
watch.  As  soon  as  the  plate  has  been  sufficiently  ex- 
posed to  the  light,  the  sliding  door  is  shut  down  and  the 

I 


114     OPERATIONS  AND   PROCESSES  OF  PHOTOGRAPHY. 

plate  removed  in  its  frame  to  the  dark  room,  where  the 
picture  has  next  to  be  developed. 

Development  of  the  image. — After  carefully  exclud- 
ing all  white  light  from  the  room  the  plate  is  now  re- 
moved from  the  dark  slide  and  held  by  a  corner  between 
the  thumb  and  forefinger  in  a  horizontal  position  ;  the 
developing  solution  is  then  rapidly  poured  over  its  sur- 
face in  such  a  way  that  the  entire  film  is  covered  at 
once,  as  if  it  is  arrested  and  allowed  to  remain  for  a  second 

Fig.  25. 


WASHING   THE   DEVELOPED   IMAGE. 


longer  in  one  place  than  another,  it  will  certainly  produce 
an  indelible  stain.*      After  the  liquid  has  been   made  to 


The  developer  for  collodion  negatives  is  formed  of  a  solution  of  proto- 


THE  NEGATIVE.  II5 


flow  in  all  directions  it  is  returned  to  the  glass  and  the 
operation  repeated  until  the  image  is  sufficiently  de- 
veloped. Before  the  application  of  the  developer  the 
plate  presents  an  exactly  similar  appearance  to  what  it 
did  prior  to  exposure,  and  not  the  slightest  trace  of 
any  picture  is  visible,  but  almost  the  instant  the  develop- 
ing agent  is  applied  a  change  takes  place ;  first  the 
lights  appear,  then  the  shadows,  then  the  half-tones. 
But  it  is  a  negative,  that  is  to  say  the  whites  of  the 
model  appear  in  black  on  the  glass  and  vice  versa. 

It  is  during  this  operation  that  one  may  easily  de- 
termine if  the  time  of  exposure  has  been  correctly  calcu- 
lated. If  it  has  been  too  short,  the  whites  appear  in- 
stantly almost  like  ink  blots,  whilst  in  the  shades  and 
blacks  the  collodion  remains  opaline  and  unaltered.  If, 
on  the  other  hand,  the  exposure  has  been  too  long,  the 
whole  surface  becomes  covered  with  a  greyish  cloudiness 
on  contact  with  the  developer,  and  the  picture  is  without 

sulphate  of  iron  in  distilled  water.  A  little  acetic  acid  is  usually  added 
with  a  few  dops  of  alcohol.     The  following  makes  a  good  developer : — 

Distilled  Water       ......  i  ounce. 

Protosulphate  of  Iron      .         .         .         .         •        '5  grains. 

Acetic  Acid 20  minims. 

Alcohol  .......        25  minims. 

This  solution  can  be  made  just  before  it  is  wanted  for  use.  The 
strength  and  proportions  of  the  ingredients  in  this  solution  may  be  greatly 
modified,  but  the  alcohol  should  be  added  little  by  little  until  the  developer 
flows  freely  and  evenly  over  the  plate. 

I  2 


Il6     OPERATIONS  AND   PROCESSES  OF   PHOTOGRAPHY. 

sharpness.  In  either  case  it  is  necessary  to  recommence 
the  operation. 

When  the  exposure  has  been  nicely  timed,  the  pic- 
ture appears  gradually  as  if  by  enchantment,  clear,  pure, 
sharp  ;  the  details  are  admirably  distinct ;  the  lights  are 
free  from  stains,  and  the  blacks  are  represented  by 
distinct  tones  varying  according  to  the  depths  of  the 
shadows. 

A  great  number  of  substances  are  known  at  the 
present  time  which  are  capable  of  developing  the  picture; 
bisulphate  of  iron  and  ammonia,  pyrogallic  and  formic 
acid,  have  been  recommended  by  some  operators. 

It  often  happens  that  a  negative  picture  is  perfect  as 
regards  sharpness,  but  is  wanting  in  intensity.  In  this 
case  the  vigour  necessary  to  obtain  a  positive  proof  may 
be  imparted  to  it  by  the  process  of  intensifying. 

Intensifying, — The  developed  plate  is  well  washed, 
and  is  then  subjected  to  the  action  of  the  developing 
solution,  which  must,  however,  contain  a  small  quantity 
of  the  silver  solution  (one  or  two  drops  of  the  bath  will 
do  very  well).'  An  intensifying  solution  may  also  be 
formed  of  water  to  which  pyrogallic  acid  dissolved  in 
alcohol  and  acetic  acid  has  been  added. 

•  Re-developing  solution  : — 

Pyrogallic  Acid        .         .         .         .         .2  grains. 

Citric  Acid      ......     3  grains. 

Water i  ounce. 


THE   NEGATIVE.  11/ 


After  the  operation  of  intensifying,  as  also  after  that 
of  development,  the  plate  must  be  well  washed,  to  re- 
move all  traces  of  the  iron  and  reagents  which  have  been 
used.  At  least  a  quart  of  water  should  be  poured  on 
to  the  plate,  care  being  taken  that  it  does  not  get  under 
the  collodion  film. 

Fixing  the  negative. — To  fix  the  negative  it  is  neces- 
sary to  deprive  it  of  the  iodide  of  silver,  which,  not 
having  been  affected  by  the  light,  would  darken  when 
exposed  to  it. 

Hyposulphite  of  soda  dissolves  the  unaltered  iodide 
of  silver. 

The  negative  being  developed  and  washed  is  now 
plunged  into  a  solution  of  hyposulphite  of  soda  in  water 
contained  in  a  porcelain  dish  (8  oz.  of  hypo,  to  40  oz.  of 
water),  and  allowed  to  remain  there  for  a  minute  or  two 
until  the  yellow  coating  of  iodide  of  silver  is  entirely 
dissolved.  The  plate  should  be  raised  out  of  the  bath  with 
a  hook  and  carefully  examined  and  returned  to  the 
bath  if  the  slightest  trace  of  the  silver  is  visible.  When 
perfectly  clear  it  must  be  well  washed  as  before  to  get 
rid  of  the  hyposulphite  adhering  to  its  surface. 

Cyanide  of  potassium  (a  most  deadly  poison)  is  also 
used  for  fixing  purposes ;  it  is  employed  in  the  same  way 
as  the  developing  solution,  and  is  cleaner  and  gives  per- 


Il8     OPERATIONS   AND    PROCESSES   OF   PHOTOGRAPHY. 

haps  a  more  vigorous,  sharp  picture,  with  finer  detail 
than  the  hypo.  (8  or  lo  grains  of  cyanide  of  potassium 
to  I  oz.  of  water). 

The  negative  is  now  finished  and  may  be  exposed  to 
light.  But  the  collodion  film  is  liable  to  be  scratched  on 
the  least  contact  with  a  hard  surface  or  with  the  finger 
nails  ;  it  is  therefore  necessary  to  protect  it  by  covering 
it  R\'ith  a  coat  of  varnish. 

A  special  varnish  is  sold  for  this  purpose,  which  is 


Fig.  26. 


RACK    FOR    DRYING    PLATES. 


transparent,  soon  dries,  and  becomes  very  hard.     The 
plate  should  be  gently  heated  over   a  spirit  lamp  or 


THE   NEGATIVE. 


119 


before  a  fire  (the  safer  plan),  until  it  can  be  just  borne  on 
the  back  of  the  hand,  the  varnish  is  then  poured  on 
exactly  as  if  coating  a  plate  with  collodion,  and  the 
excess  returned  to  the  bottle  ;  the  plate  is  then  again 
gently  heated  until  quite  dry,  when  the  picture  will  be 
protected  from  the  effect  of  any  accidental  abrasion. 

A  less  perfect  temporary  protection  is  afforded  by  a 
solution  of  gum  arable  (10  parts  of  gum  to  about  100  of 
water). 

Fig.  2^  represents  a  useful  form  of  box  for  containing 


Fig.  27. 


PLATE   BOX. 

glass  negatives,  which  are  held  in  grooves,  and  kept  free 
from  contact  with  each  other. 


120     OPERATIONS  ANP   PROCESSES  OF  PHOTOGRAPHY 

The  image  of  the  camera  which  has  thus  been  de- 
veloped, fixed,  and  varnished,  adheres  to  the  glass,  but 
it  presents  a  negative  picture  of  which,  viewed  by  trans- 
mitted light,  the  blacks  are  the  whites  of  the  model. 

We  shall  now  see  how  the  positive  proof  on  paper  is 
obtained  ;  but  we  think  it  would  be  well  first  to  point 
out  a  few  characteristics  by  which  a  good  negative  may 
be  known.  It  is  not  always  an  easy  matter  to  determine  ; 
to  an  unpractised  eye  a  plate  might  appear  excellent, 
in  which  a  skilful  operator  would  perceive  faults  which 
would  prevent  its  yielding  a  good  positive.  In  a  good 
negative  viewed  by  transmitted  light  the  shadows, 
draperies,  and  stuffs  should  be  highly  transparent.  The 
whites  and  high  lights  on  the  contrary  should  appear 
almost  perfectly  black  or  opaque. 

It  should  also  present  a  marked  shading  between  the 
half-tones  and  in  general  a  well-defined  gradation  of 
light  and  shade.  If  during  this  examination  pin-holes, 
stains  or  streaks  are  apparent,  or  if  the  most  minute 
details  and  smallest  objects  are  not  clearly  and  sharply 
defined,  another  photograph  should  be  taken.  The  im- 
perfections of  the  negative  are  exaggerated  in  the  print, 
and  all  one's  toil  and  trouble  thrown  away. 

It  often  happens  that  the  operator  searches  in  vain 
for  the  cause  of  imperfections  in  a  negative,  in  taking 


THE   NEGATIVE.  121 


which  he  seems  to  have  used  every  precaution  ;  it  is  im- 
possible to  lay  down  fixed  rules  to  meet  every  failure. 
But  the  beginner  should  bear  in  mind  that  unforeseen 
accidents  are  rocks  ahead,  which  he  will  frequently  meet 
with  in  his  labours. 

The  photographer,  like  the  chemist,  should  be  patient, 
persevering,  and  endowed  with  tenacity  ;  difficulties,  far 
from  discouraging,  should  serve  to  stimulate  him  ;  he 
should  not  be  disheartened  at  repeated  failure,  but  learn 
to  lean  more  and  more  on  that  great  teacher,  experience. 


122     OPERATIONS   AND   PROCESSES   OF   PHOTOGRAPHY. 


CHAPTER    III. 

THE   POSITIVE   ON    PAPER. 

PRINTING  ON  PAPER— OF  THE  NATURE  AND  QUALITIES  OF  PHOTO- 
GRAPHIC PAPERS — VIGNETTES— EXPOSURE  TO  THE  LIGHT— TONING, 
FIXING,    PRESSING   THE    PROOFS. 

Preparation  of  the  sensitised  paper. — Photographic  paper 
can  be  bought  partially  prepared  ;  it  is  formed  of  close- 
grained  pulp  and  presents  a  surface  smooth  and 
glossy. 

It  is  easily  prepared.  A  paper  of  good  quality  is 
chosen,  its  surface  must  be  free  from  stains.  It  is  neces- 
sary that  the  sizing  of  the  paper  should  be  very  care- 
fully done.  The  different  processes  of  sizing  give  diffe- 
rent colours  in  the  positive.  If  albumen  is  used,  the 
proof  will  be  slightly  red  ;  whilst  if  gelatine  is  used,  it 
will  be  of  an  orange-red  colour.^ 

The  paper  being  chosen,  the  albumenised  being 
most  generally  used,  it  is  next  plunged  into  a  solution 

•  The  colour,  as  will  be  seen,  depends  greatly  on  the  subsequent  toning 
with  gold. — Ed. 


THE    POSITIVE   ON    PAPER.  1 23 

of  salt  or  chloride  of  sodium  (450  grs.  to  2  pints  of 
water),  in  which  it  is  allowed  to  remain  for  a  few  minutes, 
and  is  then  dried  in  the  air.  To  sensitise  the  paper  thus 
prepared,  it  is  only  necessary  to  float  the  sized  surface 
on  a  bath  of  nitrate  of  silver  (60  grains  of  silver  to  i 
ounce  of  distilled  water)  contained  in  a  porcelain  dish. 
When  the  surface  is  well  saturated,  it  is  allowed  to  dry  in 
the  dark. 

The  albumenised  paper  of  commerce  contains 
chloride  of  sodium  or  ammonium,  and  to  sensitise  it  it  is 
only  necessary  to  float  it  on  the  silver  bath  ;  but  it  ought 
not  to  be  sensitised  long  before  it  is  intended  for  use,  as 
it  soon  turns  yellow  even  when  kept  in  the  dark. 

It  may  be  well  to  mention  here  that  the  silver  bath 
for  the  collodion  plate  must  be  kept  separate,  and  never 
used  for  any  other  purpose.  The  slightest  admixture  of 
any  foreign  substance  would  at  once  render  it  useless. 
It  should  be  filtered  when  necessary. 

The  bath  for  sensitising  the  paper  can  be  used  over 
and  over  again,  nitrate  of  silver  being  added  from  time 
to  time  to  strengthen  it.  The  solution  will  become  dis- 
coloured after  a  few  sheets  have  been  floated  on  it,  but 
this  colouring  matter  can  be  readily  precipitated  by 
means  of  a  little  Kaolin  powder,  when  the  cleared  portion 
of  the  liquid  may  be  gently  decanted  into  another  bottle. 


124     OPERATIONS  AND   PROCESSES  OF   PHOTOGRAPHY. 

Printing  from  the  negative. — Special  frames  called 
printing  frames  of  various  sizes  are  used  in  this  operation. 
The  printing  frame,  oblong  in  form,  is  made  of  wood  to 

Fig.  28, 


THE   PRINTING   FRAME. 


hold  the  glass  plate,  in  the  same  way  as  an  ordinary 
picture  frame,  but  the  back  is  provided  with  a  double 
door  hinged  across  the  centre,  which  can  be  fastened 
down  by  means  of  transverse  bars  of  wood  (see  fig.  28). 
The  printing  frame  is  provided  with  a  sheet  of  plate 
glass,  which  must  be  perfectly  clean  on  both  sides  ;  the 
negative  is  then  laid  down  with  its  uncoated  side  next 
the  plate  glass.  The  sensitised  surface  of  the  paper  is 
now  placed  on  the  collodion  film  and  the  whole  securely 
fastened,  and  held  in  close  contact  by  means  of  the 
wooden  back,  which  is  lined  with  black  felt.  This 
operation  having  been  conducted  in  the  dark  room,  the 
plate  is  now  ready  for  exposure  to  sun-light. 


THE   POSITIVE   ON    PAPER.  125 

If  the  negative  is  vigorous  and  intense,  it  may  be 
exposed  to  the  direct  rays  of  the  sun,  if  weak  and  not 
sufficiently  intense,  it  should  be  placed  in  the  shade. 
During  the  process  of  printing,  it  is  necessary  to  examine 
the  proof  from  time  to  time  until  the  requisite  depth  of 
colour  is  attained.  This  may  be  done,  of  course  in  the 
shade,  by  removing  one  of  the  transverse  bars  and  turn- 
ing back  the  top  half  of  the  hinged  back  ;  the  part  of 
the  paper  thus  set  free  can  then  be  seen  without  fear  of 
shifting,  which  would  of  course  spoil  the  picture.  If  not 
sufficiently  printed,  the  paper  is  again  fastened  down, 
and  the  exposure  continued  (fig.  29  represents  the  print- 
ing frame  exposed  to  the  sun). 

When  vignette  pictures  are  required,  a  vignette 
glass  is  used.^  This  is  a  glass  colourless  in  the 
centre,  but  towards  the  sides  tinted  yellow,  the  colour 
gradually  increasing  in  depth.  A  vignette  glass  may  be 
made  by  pasting  layers  of  paper  over  a  glass  plate  in 
such  a  way  that  whilst  the  desired  space  in  the  middle 

'  The  simplest  method  of  vignetting  is  to  cut  an  oval  aperture  in  a  sheet 
of  opaque  cardboard,  about  a  third  smaller  than  the  space  to  be  taken  up 
by  the  finished  picture.  The  aperture  must  then  be  covered  by  a  thin  sheet 
of  tissue  paper.  This  vignetting  screen  is  fixed  outside  the  plate-glass  of 
the  frame,  care  being  taken  to  place  the  aperture  directly  above  the  part  to 
be  vignetted.  When  the  card  is  in  position  the  frame  must  then  be  placed 
so  that  the  direct  rays  of  the  sun  passing  through  the  tissue  paper  will 
become  diffused,  and  print  a  delicately  shaded  vignette  of  the  required 
dimensions. — Ed. 


126     OPERATIONS  AND   PROCESSES  OF   PHOTOGRAPHY. 

of  the  glass  is  left  open,  it  gradually  becomes  opaque 
towards  the  edges,   the  thickest  layer  of  paper  being 

Fis:.  29. 


PRINTING   FRAMES   EXIOSED  TO   THE   LIGHT. 


farthest  from  the  transparent  centre.     The  action  of  the 
vignette  glass  will  be  easily  understood.     It  is  placed 

Fig.  30. 


SIMPLE    PRINTING    FRAME. 


over  the  negative,  and  thus  the  action   of  the  light  is 
confined  to  the  transparency  of  the  centre,  acting  only 


THE  POSITIVE  ON   PAPER.  12/ 

slightly  through  the  thinner  paper,  or  fainter  yellow  of 
the  vignette  glass  ;  the  rest  of  the  proof  being  perfectly 
protected,  a  white  background  is  thus  obtained. 

As  soon  as  the  printing  has  been  sufficiently  pro- 
longed (the  time  varies  according  to  the  intensity  of  the 
light),  and  shows  the  desired  depth  of  colour,  it  is  re- 
moved from  the  frame  in  the  dark  room,  and  subjected 
to  the  operation  of  toning  and  fixing. 

An  albumenised  print  on  being  taken  from  the  frame 
should  be  of  a  very  dark  brown  tone,  or  slightly  bronzed 
in  the  shadows  ;  it  will  lose  much  of  its  intensity  when 
fixed  ;  the  operator  therefore  always  prints  his  pictures  a 
deeper  colour  than  he  desires  the  finished  proof. 

Toning. — If  the  excess  of  silver  is  at  once  removed 
from  the  print  by  means  of  hyposulphite  of  soda,  the 
result  is  a  picture  deficient  in  depth,  and  of  a  disagreeable 
pale  red  colour.  The  print,  after  being  allowed  to  soak 
in  a  basin  of  cold  water,  is  therefore  first  plunged  in  a 
toning  solution  formed  of  5  or  6  grains  of  chloride  of 
gold  to  2  pints  of  water,  a  few  grains  of  acetate  of  soda,* 
or  about  100  grains  or  half  a  tea-spoonful  of  carbonate  of 
soda  being  added  ;  the  mixture  must  be  allowed  to  rest 

•  Acetate  of  Soda i  drachm. 

Chloride  of  Gold         .....       3  grains. 
*  Water 20  ounces. 


128     OPERATIONS   AND   PROCESSES   OF   PHOTOGRAPHY. 

for  about  fifteen  minutes  before  it  is  used.  Whilst  in  this 
solution  the  prints  will  gradually  become  of  a  vigorous 
violet  or  black  tone  according  to  the  time  they  are 
allowed  to  remain  in  it ;  which  is  usually  from  lo  to  15 
minutes,  until  indeed  they  present  the  deep  sepia  colour 
which  constitutes  the  true  beauty  of  the  photograph.^ 

Fixing. — The  print  being  properly  toned  and  sub- 
sequently well  washed  is  then  ready  for  fixing.  The 
process  of  fixing  the  positive  is  very  similar  to  that  of 
the  negative.  Hyposulphite  of  soda  neutralised  by 
the  addition  of  one  per  cent,  of  chalk  gives  very  good 
results  (6  oz.  of  hypo,  to  2  pints  of  water).  An  im- 
mersion of  fifteen  minutes  in  this  solution  will  be 
sufficient  to  remove  the  unaltered  silver,  and  after  being 
again  well  soaked  in  water  three  or  four  times  changed, 
and  dried,  the  proof  is  finished. 

To  ascertain  if  the  print  is  sufficiently  washed,  a  few 
drops  of  the  last  bath  it  is  soaked  in  are  allowed  to  drip 
from  it  into  a  glass,  a  small  quantity  of  bichloride  of 
mercury  (corrosive  sublimate)  in  solution  is  then  added. 

'  There  are  various  solutions  used  for  toning,  but  that  we  have  given 
is  perhaps  one  of  the  best.  If  acetate  of  soda  is  used  the  solution  must 
stand  for  ten  or  twelve  hours  before  any  prints  are  toned  in  it ;  but  it  will 
keep  good  for  months,  a  few  grains  of  gold  being  added  from  time  to  time 
to  keep  up  its  strength.  The  carbonate  of  soda  solution  can  be  used  almost 
as  soon  as  made,  but  will  not  keep  long. 


THE   rOSITIVE   ON    PAPER. 


129 


If  the  print  has  been  sufficiently  washed  there  will  be 
no  precipitate,  if  on  the  contrary  there  is  a  precipitate, 
then  the  washing  must  be  continued  until  such  reaction 
does  not  manifest  itself. 

Motmting  and  Rolling. — The  proof  after  being  thus 


Fig.  31- 


THE    ROLLING    PRESS. 


thoroughly  washed  is  hung  up  to  dry  by  one  of  its 
corners  to  a  cord  stretched  across  the  studio,  and  when  dry 
placed  in  a  press  or  under  a  heavy  weight  to  prevent  its 
creasing.  When  cut  to  the  right  size  it  only  remains  to 
mount  the  proof  on  cardboard  and  to  roll  it. 

K 


I30     OPERATIONS  AND   PROCESSES  OF   PHOTOGRAPHY. 

The  mounting  is  best  effected  with  a  starch  paste 
prepared  with  boihng  water.  The  rolling  is  done  by 
means  of  a  special  press  (see  fig.  31)  formed  of  a  smooth 
metal  plate  which  can  be  moved  horizontally  backwards 
and  forwards  under  a  roller  by  means  of  a  toothed 
wheel  and  pinion.  The  mounted  proofs  after  being  dried 
in  a  warm  room  are  placed  on  the  plate  (as  shown  in  the 
illustration),  and  then  subjected  to  great  pressure  by 
being  passed  under  the  roller.  This  gives  them  a 
beautiful  gloss  and  finish. 

Such  are  the  different  operations  which  have  to  be 
performed  to  obtain  a  positive  photographic  proof  by 
the  most  generally  practised  method  from  a  collodion 
negative.  We  will  only  add  that,  however  minute  the 
descriptions,  practice  is  the  operator's  best  guide.  He 
should  endeavour  to  master  the  theory  of  the  different 
processes,  but  must  not  forget  that  a  long  apprenticeship 
is  necessary,  and  that  patience  and  unwearying  applica- 
tion are  indispensable  qualities  in  the  photographer. 

To  anyone  ever  so  little  acquainted  with  chemical 
manipulations  the  different  operations  which  we  have 
just  described  are  not  very  difficult ;  but  what  protracted 
efforts,  what  a  delicate,  patient,  minute  feeling  of  the  way 
it  required  on  the  part  of  the  inventors  of  the  wonderful 
art !     What  an  abyss  of  labour  and  research  separate 


THE   POSITIVE   ON    PAPER.      •  131 

the  actual  methods  of  which  we  have  just  given  an 
outHne,  from  the  first  experiments  of  Niepce  and 
Daguerre ! 

After  these  grand  inventors,  what  numbers  of  in- 
genious and  laborious  minds  have  long  worked  at  the 
problems  of  photography,  each  adding  some  new  ele- 
ments to  the  results  obtained  before  them ! 

May  we  not  say  that  it  is  the  character  of  the  works 
of  modern  science  to  be  in  a  great  measure  the  result  of 
multiplied  efforts,  isolated  from  each  other,  but  simul- 
taneous and  all  tending  to  the  same  end  ?  Most  of  the 
discoveries  of  our  century  are  a  striking  proof  of  this  ; 
and  photography  is  certainly  one  of  those  which  has  de- 
manded the  greatest  concourse  of  intelligent  workers, 
pursuing  with  perseverance  researches  always  difficult 
and  often  unprofitable. 


K  2 


132      OPERATIONS   AND    PROCESSES   OF   PHOTOGRAPHY. 


CHAPTER    IV. 

THEORY   AND    PRACTICE. 

EXPLANATION  OF  PHOTOGRAPHIC  OPERATIONS — NECESSITY  OF  LONG 
PRACTICE — MODIFICATIONS  IN  PROCESSES  REQUIRED  BY  DIFFERENT 
SORTS  OF  PHOTOGRAPHY— PHOTOGRAPHY  AND  TRAVEL— LANDSCAPES 
— SKIES  —PORTRAITS— INSTANTANEOUS    PHOTOGRAPHY. 

We  have  described  the  different  operations  which  the 
production  of  a  photographic  proof  necessitates  ;  we  do 
not  think  it  is  necessary  to  expatiate  on  the  theory  of 
the  reactions  on  which  is  based  the  series  of  photo- 
graphic manipulations.  In  the  historical  part  w^e  have 
already  referred  to  the  scientific  groundwork  of  photo- 
graphy ;  a  few  new  details  may,  however,  help  to  better 
fix  the  reader's  ideas. 

It  is  not  known  by  what  wonderful  influence  light 
affects  certain  chemical  agents ;  science  is  almost  always 
powerless  to  explain  causes;  it  discovers  effects,  it  brings 
them  under  control  and  profits  by  their  application. 

Light  acts  on  the  nitrates  of  silver.*     Why  ?     No 

'  Light,  as  we  have  seen,  acts  also  on  a  great  number  of  other  substances. 
Here  is  a  curious  experiment  which  plainly  shows  its  action.  It  was  made 
by  Messrs.  Gamier  and  Salmon,  and  published  in  the  Bulletin  of  the  French 


THEORY  AND   PRACTICE.  1 33 

one  knows  and  perhaps  no  one  ever  will  know,  but  the 
fact  is  manifest,  and  this  action  is  the  fundamental  basis 
of  photography. 

The  glass  plate  is  covered  with  collodion,  a  viscous 
substance  which  solidifies  on  contact  with  air,  and  is 
well  adapted  as  a  base  for  the  silver  solution.  The  col- 
lodion contains  iodide  of  potassium  ;  when  the  coated 
plate  is  plunged  into  the  nitrate  of  silver  bath,  the  iodide 
of  potassium  is  transformed  into  iodide  of  silver. 

The  plate  thus  sensitised  is  exposed  in  the  camera. 
The  light  acts  on  the  iodide  of  silver  in  the  light  parts  of 
the  picture,  leaving  the  shadows  intact.  On  being  taken 
from  the  camera  the  picture  is  developed  by  means  of  a 
solution  of  proto-sulphate  of  iron  to  which  acetic  acid  has 
been  added.  The  sub-chloride  of  silver  formed  by  the 
action  of  light  being  completely  reduced,  the  metallic  silver 
is  deposited  and  soon  becomes  a  very  pronounced  and 
vigorous  dark  shade.  If  not  sufficiently  vigorous  at  first 
it  is  intensified  by  the  addition  of  a  little  nitrate  of 
silver  solution  to  the  redeveloper,  which  is  poured 
over  the  plate,  and  a  fresh  quantity  of  metal  deposits  on 
the  parts  already  reduced,  strengthening  the  picture  and 

Photographic  Society.  Sulphur  undergoes  a  singular  alteration  when  sub- 
mitted to  the  action  of  light.  If,  after  being  thus  exposed,  it  is  brought 
into  contact  with  fumes  of  mercury,  the  fumes  only  attack  those  parts  which 
have  been  acted  upon  by  the  light,  turning  them  a  brown-yellow  colour. 


134      OPERATIONS  AND   PROCESSES  OF  PHOTOGRAPHY. 

giving  it  greater  intensity.  The  fixing  is  done  by  means 
of  hyposulphite  of  soda  or  cyanide  of  potassium  ;  these 
salts  dissolve  the  iodide  of  silver  which  has  not  been 
affected  by  the  light. 

It  will  be  seen  that  these  theoretical  outlines  are  ver>^ 
simple  ;  it  is  not  necessary  to  be  versed  in  the  study  of 
chemistry  to  understand  them.  But  the  theory  of  an  art 
and  the  being  able  to  practise  it  are  very  different  things. 
The  latter  is  only  to  be  acquired  by  long  and  patient 
manipulations,  by  numerous  and  often-repeated  experi- 
ments. It  is  the  more  difficult  to  be  taught  in  a  work 
such  as  the  present,  inasmuch  as  it  varies  according  to 
the  result  desired. 

All  that  we  have  so  far  said  on  photographic  opera- 
tions refers  principally  to  experiments  made  in  a  studio 
where  the  light  can  be  controlled  at  will,  and  where  a 
dark  room  and  all  the  necessary  apparatus  are  at  hand. 
But  we  have  not  entered  into  the  particular  details  of  the 
precautions  which  are  necessary  in  taking  portraits  from 
nature;  we  have  passed  in  silence  the  accidental  causes 
which  alter  a  negative — in  one  word  the  minutiae  which 
practice  alone  can  teach.  Just  as  it  is  impossible  to  become 
a  chemist  without  studying  in  a  laboratory,  so  is  it  folly  to 
hope  to  become  a  photographer  except  with  the  col- 
lodion bottle  in  the  hand  and  the  camera  before  the  eyes. 


THEORY  AND   PRACTICE.  1 35 

Nevertheless,  as  the  inexperienced  beginner,  learning 
for  himself,  must  have  recourse  to  the  advice  which  books 
offer  him,  and  as  at  present  we  have  not  sufficiently  re- 
ferred to  the  different  applications  of  photography,  we 
shall  give  some  information  respecting  the  various  modes 
of  operation  which  are  necessary  for  photography  in 
travel,  instantaneous  photography,  and  some  special 
branches  of  the  art. 

Outdoor  PhotograpJiy. — The  travelling  apparatus 
differs  from  that  of  the  studio  ;  it  is  much  lighter  and 
more  portable.  The  camera  is  much  smaller  and  is 
furnished  with  a  bellows  which  can  be  extended  and  con- 
tracted at  the  will  of  the  operator.  It  is  supported  on 
a  tripod  stand,  the  feet  of  which  fold  up,  or  slide  in 
grooves.  It  is  furnished  with  straps  which  secure  almost 
all  the  apparatus,  including  a  tent  to  serve  as  a  dark 
room.  The  whole  can  be  easily  adapted  to  the  shoulders 
of  the  tourist,  so  that  he  may  thus  carry  his  complete 
material  without  fatigue.     (See  fig.  32.) 

The  lens^  screws  on  to  the  camera,  so  that  it  may  be 
carried  separate.  This  lens  is  simple,  that  is  to  say  it 
consists  of  but  one  achromatic  lens,  sufficient  for  photo- 

'  In  England  view  lenses  are  manufactured  in  great  variety, 
double  and  single  wide  angled,  with  short  focus,  and  others  with  a  more 
contracted  field  and  longer  focus.  Many  lenses,  such  as  those  of  Ross  and 
Dallmeyer,  are  deservedly  famed  all  over  the  world. — Ed. 


136      OPERATIONS  AND   PROCESSES   OF    PHOTOGRAPHY. 

graphs  of  views  and  monuments.     We  specially  recom- 
mend the  orthoscopic  lens  invented  at  Vienna.     It  con- 
Fig.  32. 


PORTABLE    PHOTOGRAPHIC   APPARATUS. 


sists  of  a  double  combination  of  achromatic  glasses,  the 
position  of  the  diaphragms  at  the  back  of  the  lens  tube 


THEORY  AND  PRACTICE.  I  37 

permitting  the  utilisation  of  almost  all  the  light  entering 
through  the  glasses.  Another  great  advantage  it  offers 
is  that  it  gives  more  nearly  the  true  perspective  and 
straighter  lines  in  monuments  than  other  lenses. 

As  before  mentioned,  the  photographic  tourist  must 
be  provided  with  a  dark  tent,  which  can  be  procured 
very  compact  and  which  need  only  be  large  enough  to 
take  in  the  upper  part  of  the  body.  It  can  be  readily 
set  up,  and  contains  the  silver  bath,  a  rack  for  the 
various  bottles,  and  a  reservoir  on  the  top  to  hold  a  supply 
of  water  for  washing  the  plates,  a  sink  for  getting  rid  of 
waste  ;  in  fact  everything  which  the  artist  requires. 

The  photographic  tourist,  if  he  is  a  good  operator, 
will  readily  be  able  to  produce  views  of  monuments  and 
buildings  in  general ;  but  if  he  attacks  nature,  if  he  at- 
tempts studies  of  skies,  or  tries  to  fix  on  his  collodion 
the  effects  of  the  shadows  which  adorn  the  landscape, 
he  will  encounter  difficulties  which  will  prove  insur- 
mountable, unless  his  perseverance  is  equal  to  his 
ambition. 

'  One  of  the  greatest  difficulties  of  the  landscape 
photographer,'  says  the  talented  artist,  M.  A.  Liebert,  to 
whom  we  have  already  referred,  *  is  the  production  of 
skies  with  natural  clouds,  because  the  light,  from  its 
great  strength,  destroys  all  the  cloud  shadows  by  solarisa- 


138     OPERATIONS   AND   PROCESSES   OF   PHOTOGRAPHY. 

tion  ;  the  result  is  skies  whose  uniform  whiteness  pro- 
duces a  monotony  which  deprives  the  landscape  of  its 
aerial  or  natural  perspective ;  all  the  delicate  tints  pro- 
duced by  distance  and  the  reflections  of  the  clouds  dis- 
appear ;  the  image  thus  loses  a  great  part  of  its  artistic 
value. 

*  Various  methods  may  be  employed  for  obtaining 
clouds  in  the  sky  of  a  landscape.  The  first  consists  in 
operating  instantaneously  and  then  reproducing  the 
natural  sky,  which  is  thus  in  keeping  with  the  rest  of  the 
picture  ;•  but  with  a  little  practice  in  development  of 
the  image  clouds  may  be  obtained.  The  best  way  to 
manage  the  clouds  during  the  development  of  a  picture 
which  has  been  shortly  exposed  consists  in  covering  the 
glass  with  a  very  weak  neutral  reagent,  until  the  clouds 
are  developed  ;  the  rest  of  the  picture  is  then  subjected 
to  the  ordinary  development,  care  being  taken  to  con- 
fine the  solution  as  much  as  possible  to  the  landscape 
itself 

'When  a  picture  is  to  be  printed  with  the  sky  of 
another  negative  care  must  be  taken  to  select  a  sky  ap- 
propriate to  the  subject  in  order  to  secure  harmony.  In 
such  a  case  it  is  necessary  to  bear  in  mind  the  effects  of 
light,  so  that  the  clouds  and  the  picture  may  be  alike  as 
regards  the  light.      The  horizon  lines  should  keep  their 


THEORY  AND   PRACTICE.  1 39 

character,  the  sky  which  is  less  distinct  in  the  distance 
gradually  becomes  more  definite  in  the  higher  parts  of 
the  picture.  These  delicate  operations  require  great  care 
and  taste,  and,  above  all,  artistic  feeling.' 

The  same  artist  gives  excellent  advice  to  the  land- 
scape photographer,  and  with  good  right  claims  the  title  of 
work  of  art  for  a  picture  obtained  under  good  conditions. 

*  To  give  the  true  artistic  effect  of  a  landscape,  it  is 
important  to  discover  that  view  of  it  which  presents  the 
greatest  harmony  in  its  tout-ensemble,  and  to  choose 
the  time  of  day  when  this  view  is  in  the  best  light  for 
reproducing  its  objects  in  their  true  significance  and 
character,  and  when  the  effects  of  light  and  shade  are  in 
keeping  with  form  and  distance. 

'  Thus  it  will  be  seen  that  great  taste  and  judgment 
are  required  to  produce  a  picture  really  worthy  the  name 
of  a  photograph,  and  this  applies  equally  to  portrait  as  to 
landscape  work.  Unfortunately  for  the  beautiful  art  it 
is  often  enough  disgraced  by  distorted  effects  in  black 
and  white,  which  have  as  little  right  to  the  title  of  pho- 
tographs as  their  producers  to  that  of  photographers.' 

By  repeated  improvements  in  the  lens  and  the  various 
solutions  employed,  the  time  of  exposure  has  been  re- 
duced to  the  fraction  of  a  second,  so  that  it  is  possible 
to  obtain  photographs  of  a  horse  in  full  gallop,  a  pass- 


I40      OPERATIONS   AND    PROCESSES   OF   PHOTOGRAPHY. 

ing  regiment,  a  wave  just  breaking,  or  a  flying  cloud. 
The  collodion  for  instantaneous  pictures  should  be  very- 
fluid.  This  collodion  is  sensitised  with  iodide  of  lithium 
and  bromide  of  lithium.  The  silver  bath  of  8  parts  of 
silver  to  lOO  of  water  is  saturated  with  iodide  of  silver,  a 
few  drops  of  nitric  acid  are  added,  and  the  coated  plate 
is  allowed  to  remain  in  this  bath  for  five  minutes.  By 
this  means  the  maximum  of  sensibility  is  obtained. 
The  developing  solution  is  made  of  sulphate  of  iron 
to  which  acetate  of  lead,  formic  acid,  and  nitric  ether 
have  been  added.^ 


•  It  is  impossible  in  a  work  like  this  to  give  a  detailed  account  of  the 
various  instantaneous  photographic  processes.  They  all  present  difficulties 
of  manipulation  which  can  only  be  overcome  by  the  experienced  operator. 
—Ed. 


141 


CHAPTER  V. 

RETOUCHING. 

ACCIDENTS  WITH  NEGATIVES  AND  PROOFS  — METHOD  OF  REMEDYING 
THE  SAME — RETOUCHING  THE  NEGATIVE — IMPERFECTIONS  IN  THE 
POSITIVE— RETOUCHING  PHOTOGRAPHIC  PROOFS  WITH  INDIAN  INK 
— COLOURING    PHOTOGRAPHS— PHOTOGRAPHIC   CARICATURES. 

In  spite  of  every  precaution  on  the  part  of  the  operator, 
the  photographic  negative,  as  well  as  the  positive  proof, 
are  often  imperfect.  Unforeseen  and  often  inexplicable 
accidents  frequently  mar  work  which  has  cost  much 
time  and  trouble. 

A  few  seconds'  over-exposure,  the  development  pushed 
a  little  too  far,  the  slightest  impurity  finding  its  way  into 
any  of  the  reagents  employed,  a  ray  of  light — any  one  of 
these  is  sufficient  to  spoil  the  picture,  cover  it  with  a 
cloudy  fogginess,  puncture  it  with  pin-holes,  or  mark  it 
with  lines  which  destroy  the  purity  of  the  drawing. 

Pin-holes  and  small  spots  on  the  negative  often  arise 
from  badly  cleaned  glasses.  If  there  happen  to  be  a  few 
grains  of  Tripoli  powder  or  a  few  dust  spots  on  the  plate, 
the  collodion  coating  will  make  them  apparent  however 


142      OPERATIONS   AND   PROCESSES   OF   PHOTOGRAPHY. 

minute  ;  they  will  prevent  the  developer  acting  on  the 
spot  they  cover,  and  will  form  very  visible  marks  in  the 
proof. 

Transparent  pin-holes  in  a  negative  can  be  touched 
out  with  Indian  ink  slightly  gummed. 

Imperfections  in  the  positive  proof  can  be  corrected 
by  careful  touching  with  Indian  ink  to  which  a  little 
gum  and  carmine  have  been  added. 

The  photographic  proof  can  be  used  by  the  artist  as 
a  sketch  on  which  he  can  work  with  his  pencil  or  brush, 
and  is  thus  transformed  into  a  miniature  or  crayon. 

Protests  against  the  use  of  pencil  or  brush  on  the  pho- 
tographic proof  have  not  been  wanting  ;  in  the  Third  Part 
of  this  work  we  shall  consider  the  system  of  retouching 
from  the  artistic  point  of  view  ;  for  the  present  we  shall 
only  regard  it  in  a  purely  practical  light. 

The  retouching  a  positive  proof  with  Indian  ink 
should  be  done  before  the  operation  of  rolling  ;  it  is  very 
rare,  we  repeat,  that  this  retouching  is  not  necessary, 
especially  in  portraits.  The  sitter  often  moves  his  eyes, 
which  prevents  their  appearing  sufficiently  distinct  and 
sharp  in  the  photograph  ;  the  draperies  do  not  always 
present  enough  vigour  in  shade.  A  few  delicate  touches 
with  a  brush  easily  repair  these  and  similar  imperfections. 
It  is  often  necessary  to  retouch  the  whites  of  a  picture 


^RETOUCHING.  143 


which  appear  too  much  like  pure  blots  without  shade  or 
half-tones.  A  man's  shirt  nearly  always  prints  like  a 
white  triangle,  without  folds  and  without  trace  of  studs, 
and  thus  produces  a  lamentable  result  in  the  midst  of  a 
picture  which  may  be  otherwise  perfect.  A  touch  of 
Indian  ink  or  sepia  with  a  fine  brush  will  soon  remedy 
such  defects. 

Photographs  intended  to  be  coloured  with  crayon  or 
water  colours  should  be  printed  on  plain  salted  paper. 
These  coloured  proofs  rarely  look  well  ;  and  oil-painting 
on  the  positive  also  gives  but  a  poor  result.  In  the  latter 
case  the  proof  is  printed  on  canvas.  We  shall,  however, 
see  that  the  photographic  art  is  capable  of  rendering 
great  service  to  painters  of  the  greatest  talent.  \{ painted 
photographs  are  held  in  but  little  esteem  it  is  because 
they  mostly  owe  their  origin  to  coloiirers  rather  than  to 
real  artists,  and  because  they  are  destined  for  slender 
purses  demanding  six  portraits  for  six  shillings.  But,  it 
seems  to  us,  in  a  great  many  cases  that  the  photograph 
might  very  well  serve  as  the  sketch  for  the  painter.  It 
is  to  be  regretted  that  good  artists  do  not  oftener  make 
use  of  it. 

F^g-  33  represents  a  photographic  caricature  which  is 
obtained  as  follows.  To  represent  a  large  head  on  a 
small  body  a  picture  of  the  head  alone  is  first  taken  and 


144     OPERATIONS   AND   PROCESSES   OF    PHOTOGRAPHY. 

then  a  picture  of  the  entire  body  on  a  much  smaller 
scale.  Proofs  are  taken  on  paper  from  the  two  nega- 
tives, and  then  the  large  head  is  cut  out  and  pasted   on 

Fig-  33- 


PHOTOGRAPHIC  CARICATLRE. 


to  the  shoulders  of  the  figure  on  the  smaller  scale.  If 
the  large  head  does  not  fit  very  well  on  to  the  small  body 
the  neck  is  touched  up  with  a  brush.     A  photograph  is 


RETOUCHING.  1 45 


then  taken  of  the  picture  thus  obtained,  and  the  negative 
produced  will  furnish  any  number  of  caricature  proofs. 

Similar  processes  to  that  just  described  are  often 
made  use  of  for  the  production  of  political  photographs. 
A  new  ministry  comes  in,  and  in  a  day  or  two  photo- 
graphs are  on  sale  everywhere  of  its  members  in  council. 
It  is  certain  the  august  body  has  not  devoted  one  of  its 

*  sittings  '  for  the  purpose  of  being  photographed.  How 
then  is  the  picture  obtained  ?  Nothing  more  simple. 
Some  enterprising  photographer  seats  a  number  of  his 
friends  round  a  large  table  covered  with  a  green  cloth  ; 
on  a  background  a  handsome  marble  mantelpiece  and 
a  splendid  chandelier  are  painted  to  represent  the 
ministerial  room.  He  takes  a  photograph  of  this  scene, 
obtains  a  positive  proof  on  paper,  cuts  out  the  heads  of 
the  models,  and  inserts  in  their  places  the  heads  of  the 
new  ministers  cut  from  their  carte-portraits.  After 
being  touched  where  necessary  with  the  brush,  a  new 
photograph  of  this  composition  is  taken  and  the  thing  is 
done.     The  interview  between  Bismarck  and  Thiers  was 

*  photographed  '  in  this  way. 

Photography  offers,  indeed,  a  mine  of  pleasant  diver- 
sions for  the  observer  ;  but  we  shall  not  go  into  this 
branch  of  the  art  which  we  are  studying  from  a  practical 
point  of  view. 

L 


146     OPERATIONS   AND   PROCESSES   OF    PHOTOGRAPHY. 

We  can  only  add,  to  keep  within  the  limits  of  this 
chapter,  that  careful  artistic  retouching  helps  to  improve 
the  photograph  by  giving  the  portrait  the  true  aspect  of 
the  human  face  J 

*  Madame  de  Stael,'  says  our  witty  writer  M.  Legouv^e, 
'  died  talking  ;  for  several  days  her  relatives  seeing  the 
fatal  end  approaching  endeavoured  in  vain  to  keep 
visitors  from  her  bed  of  agony  :  "  Let  them  come  in,  let 
them  come  in,"  she  cried  in  a  feverish  voice  ;  "  I  thirst  for 
the  human  face ! "  This  profound  and  almost  terrible 
saying  expresses  one  of  the  most  ardent  passions  of  our 
time ;  we  have  all  a  thirst  for  the  human  face.  Stop 
before  an  exhibition  of  photographs  or  prints,  watch  the 
crowd  which  presses  round,  and  note  its  inquisitive 
attention.  ...  Is  this  pure  curiosity  >  Simple  love  of 
diversion  ?  Frivolous  idleness  ?  No.  .  .  .  We  thirst  for 
the  human  face,  because  we  thirst  for  the  human  mind.* 

The  desire  thus  referred  to  by  M.  Legouve  is  real, 
and  certainly  no  one  would  question  its  bearing  on  pho- 
tography ;  therefore  we  say  to  the  retouchers  :  *  Give  us 
the  human  face.* 

•  This  would  almost  seem  to  be  a  left-handed  compliment  to  photography 
if  the  author  had  not  already  convinced  us  of  his  profound  admiration  of  the 
art  and  its  capabilities.  For  my  own  part  I  think  that  photography  in  the 
hands  of  a  skilled  and  artistic  operator  is  capable  of  producing  results 
which  can  never  be  improved  by  retouching. — Ed. 


147 


CHAPTER   VI. 

ENLARGEMENT   OF   PROOFS. 

APPARATUS  EMPLOYED  FOR  ENLARGING  NEGATIVE  PROOFS — WOOD- 
WARD'S SYSTEM — MONCKHOVEN'S  APPARATUS — UNIVERSAL  SOLAR 
CAMERA. 

It  often  occurs  that  photographs  of  the  natural  size  of 
objects  are  required.  But  to  obtain  a  large  negative, 
say  a  yard  square  for  example,  by  the  ordinary  process 
is  next  to  an  impossibility.  How  could  a  plate  of  such 
a  size  be  properly  cleaned,  how  coated  with  collodion, 
how  could  the  developing  liquid  be  applied  ?  ^  By  the 
usual  processes  it  may  be  said  that  such  manipulations 
would  be  completely  impossible  even  to  the  most  expert 
operator. 

'  Plates  a  yard  square  and  even  larger  are  manipulated  by  the  Auto- 
type Company  and  other  photographic  firms  in  London.  — Ed. 

L  2 


148     OPERATIONS   AND    PROCESSES   OF   PHOTOGRAPHY. 

The  best  means  of  obtaining  a  picture  approaching 
the  natural  size  of  the  object  seems  to  consist  in  the 
enlargement,  by  optical  apparatus,  of  a  small  negative 
which  has  been  obtained  as  perfect  as  possible. 

The  ordinary  method  of  enlarging  consists  in  pro- 
jecting the  image  of  a  negative  plate  by  means  of  the 
lens  of  a  megascope  on  to  sensitised  paper,  where  it  is 
fixed.  The  Image,  enlarged  like  that  of  the  magic 
lantern  slide,  is  faithfully  reproduced  on  the  photographic 
paper. 

Though  the  theory  of  this  operation  is  simple  enough, 
its  practice  is  somewhat  difficult  and  requires  a  \^xy  per- 
fect instrument.  Mr.  Woodward's  apparatus  consists  of  a 
large  wooden  case  containing  the  negative,  the  image  of 
which  is  powerfully  illuminated  and  projected  with  the 
required  degree  of  amplification  on  to  the  photographic 
paper. 

M.  Monckhoven  has  improved  this  system  by  adapt- 
ing a  second  lens  to  the  megascope  which  corrects  the 
spherical  aberration.  The  negative  is  held  in  a  frame 
(fig.  34),  the  enlarging  lens  is  contained  in  a  metal  tube, 
and  the  enlarged  image  is  thrown  on  a  screen  at  some 
yards'  distance  from  the  apparatus. 

The  illustration  (fig.  34)  shows  the  general  appear- 
ance of  the  apparatus.     On  the  right  of  the  drawing  will 


ENLARGEMENT   OF    PROOFS. 


149 


be  seen  a  thin  partition 
which  separates  the 
operating  room  from 
the  outer  air.  This 
room  should  be  ex- 
posed to  the  south.  The 
enlarging  camera  is 
fixed  to  an  opening  in 
the  partition,  through 
which  a  powerful  light 
is  thrown  by  means  of  a 
reflector  which  follows 
the  sun  outside,  and 
transmits  the  rays 
through  a  large  lens 
which  condenses  them 
on  to  the  glass  nega- 
tive to  be  enlarged ; 
after  passing  through 
the  negative  it  next 
traverses  the  enlarging 
lens,  carrying  with  it 
the  image  to  be  repro- 
duced, and  thrown  in 
the  required  size  upon 


150     OPERATIONS  AND   PROCESSES   OF   PHOTOGRAPHY. 

the  screen  fixed  at  some  yards' distance.^  This  distance 
should  be  about  three  yards  to  obtain  a  photograph 
one  yard  in  diameter. 

Fig-  35- 


LI^BERT'S   enlarging    APPARATl'S. 


M.  Liebert  has  invented  an  enlarging  apparatus 
which  has  advantages  over  the  preceding.  It  is  much 
more    economical    and    does    not  require    any   special 


'  The  size  of  the  enlarged  image   also  depends  on  the  focal  length  of 
object-glass.  — Ed. 


ENLARGEMENT  OF   PROOFS.  151 

fixed  position.  It  can  be  used  from  sunrise  to  sunset, 
which  is  not  the  case  with  the  apparatus  illuminated 
by  reflection  which  we  have  just  described.  The  illus- 
tration (fig.  35)  gives  such  a  clear  idea  of  Liebert's  appa- 
ratus that  any  description  is  unnecessary. 

Success  in  the  enlargement  of  photographs  can  only 
be  obtained  when  the  greatest  attention  has  been  paid 
to  the  preparation  of  the  small  glass  negative,  which  re- 
quires a  special  method. 

A  thin,  quite  transparent  glass  plate  should  be  chosen 
with  a  perfectly  smooth  surface.  Liquid  collodion  must 
be  used,  to  ensure  sufficient  transparency  to  the  image 
to  be  enlarged. 

The  negative  must  be  very  transparent;  therefore 
it  should  not  be  too  vigorous  or  intense.  To  arrive  at 
this  result  such  substances  are  avoided  in  the  preparation 
of  the  developer  as  tend  to  intensify.  The  sulphate  of 
iron  solution  in  alcoholised  water  is  alone  sufficient. 

The  negative  having  to  be  exposed  to  the  sun's  rays 
should  not  be  coated  with  any  varnish  which  melts  under 
the  action  of  heat. 

The  art  of  enlarging  photographs  has  been  brought 
to  great  perfection  during  the  last  four  years.'     Some 

*  The  enlargements  obtained  in  London  by  the  Autotype  process  appear 
to  me  to  leave  almost  nothing  to  be  desired.    The  method  followed  in  their 


152     OPERATIONS   AND   PROCESSES   OF   PHOTOGRAPHY. 

operators  have  arrived  at  results  worthy  of  the  highest 
praise. 

Enlargements,  it  is  true,  offer  certain  inconveniences; 
the  details  of  the  enlarged  proof  have  often  a  disagree- 
able effect  ;  they  are  exaggerated  and  seem  as  though 
seen  under  a  magnifying  glass.  It  would,  however,  be 
unjust,  in  spite  of  these  defects,  to  underrate  the  im- 
portance of  the  results  obtained. 

production  is  totally  different  from  any  of  the  processes  described  by  the 
author.  The  most  beautiful  carbon  transparencies  are  first  taken  from 
small  negatives,  and  are  used  in" the  production  of  large  negatives  on  glass 
plates  by  the  wet  collodion  process. — Ed. 


153 


CHAPTER   VII. 

PROCESSES. 

THE  DRY-COLLODION  PROCESS— EMPLOYMENT  OF  ALBUMEN,  HONEY, 
AND  TANNIN  — WAXED-PAPER  PROCESS— PERMANENT  PHOTOGRAPHY 
BY   THE   CARBON    PROCESS— METHODS   OF    POITEVIN,    SWAN,    ETC. 

The  wet-collodion  process,  which  we  have  described  at 
some  length,  gives  excellent  proofs,  very  sharp,  and  often 
of  an  astonishing  degree  of  perfection  ;  but  it  has  one 
great  drawback.  As  soon  as  the  glass  plate  is  coated 
with  collodion  it  must  be  at  once  exposed  in  the  camera. 
If  it  is  allowed  to  dry,  it  is  no  longer  so  impressionable. 
As  the  collodion  dries  very  rapidly  it  is  very  difficult  to 
make  use  of  it  in  landscape  work,  or  in  any  way  in  warm 
climates.^ 

'  My  own  experience  when  travelling  in  the  tropics  does  not  bear  out 
the  author's  views  on  this  point.  Dry  plates  as  we  find  them  now-a-days, 
nearly,  if  not  quite  equal  to  wet  plates  in  their  sensitiveness,  are  greatly  to 
be  desired  by  the  photographer  who  may  happen  to  be  exploring  a  new 
country.  Yet  I  have  found  the  old  wet  collodion  process  in  the  tropics 
always  so  ready  and  always  so  capable  of  responding  to  my  every  wish, 
that  I  esteem  it  above  all  others.  By  certain  simple  modifications,  such 
as  adding  alcohol  to  the  collodion,  a  wet  plate  may  be  freely  exposed  for 
half-an-hour  in  a  climate  where  the  temperature  is  90°  in  the  shade. —  Ed. 


154      OPERATIONS  AND   PROCESSES   OF   PHOTOGRAPHY. 

It  had  long  been  the  endeavour  of  photographers 
to  discover  a  means  by  which  plates  coated  with  collo- 
dion and  allowed  to  dry  could  still  be  made  to  retain 
their  sensibility  to  light.  The  problem  has  been  solved 
by  the  addition  to  the  collodion  of  gummy  or  resinous 
matters,  so  that  instead  of  the  film  being  impervious,  it 
should,  on  the  contrary,  remain  porous,  so  as  to  absorb 
the  sensitising  liquid  when  required  for  use,  a  few  mo- 
ments before  its  exposure  in  the  camera. 

Dry  collodion. — The  reader  will  remember  that  albu- 
men was  employed  in  photography  until  the  discovery 
of  collodion.  It  \^  still  made  use  of  by  some  ope- 
rators in  certain  cases,  and  gives  very  good  results. 

'  TJie  albumen  pi'ocess. — A  well  cleaned  glass  plate  is 
coated  with  ordinary  iodised  collodion ;  after  being 
sensitised  and  washed  to  remove  free  nitrate  of  silver 
the  collodion  is  again  coated  with  albumen  containing 
iodide  of  ammonium,  ammonia,  and  sugar  candy. 

The  plate  thus  covered  with  a  liquid  which  preserves 
the  collodion  beneath  it  is  dried  and  then  placed  in  a 
grooved  box  which  is  perfectly  air-tight.  When  the 
plate  is  required  for  use,  it  only  remains  to  sensitise  it 
in  the  silver  bath,  and  the  concluding  operations  of 
washing  and  drying  are  effected  in  the  ordinary  way. 

The  time  of  exposure  in  this  process  is  somewhat 


PROCESSES.  155 


long  ;  to  obtain  good  results  the  directions  of  its  inventor, 
M.  Taupenot,  must  be  scrupulously  followed. 

The  cleaning  of  the  glass  requires  to  be  even  more 
carefully  done  than  in  the  wet-collodion  process.  After 
spreading  the  collodion  on  the  plate,  it  is  sensitised  in  a 
neutral  nitrate  of  silver  bath.  The  plate  is  drained  and 
then  recoated  with  the  preparation  of  albumen  or  white 
of  egg.  To  prepare  the  latter  it  is  sufficient  to  pour 
some  whites  of  eggs  into  a  glass,  and  after  adding  a  few 
drops  of  ammonia  and  a  little  iodide  and  bromide  of 
ammonium,  to  beat  up  the  mixture  well.  The  addition 
of  sugar  candy  is  useful  ;  it  keeps  the  albumen  fluid,  and 
allows  of  its  being  easily  spread  over  the  plate  as*  with 
collodion.  The  plate  once  albumenised  is  dried,  away 
from  light  and  dust,  and  may  be  used  very  advan- 
tageously five  or  six  hours  after  being  prepared. 

A  number  of  plates  are  prepared  in  this  way,  and 
when  required  for  use  they  are  sensitised  in  a  nitrate  of 
silver  bath  to  which  a  little  acetic  acid  has  been  added. 
They  are  developed  with  gallic  acid,  and  fixed  with  hy- 
posulphite of  soda. 

The  albumen  process  necessitates  a  considerable  ex- 
posure in  the  camera  ;  the  development  is  not  produced 
until  the  plate  has  been  under  the  action  of  the  develop- 
ing fluid  for  about  half  an  hour.     It  cannot  be  employed 


156      OPERATIONS   AND   PROCESSES   OF    PHOTOGRAPHY. 

for  portraiture,  but  is  well  adapted  for  reproducing 
drawings,  pictures,  and  engravings,  as  the  albumen  gives 
a  very  sharp  negative  full  of  harmony  in  tone. 

TJie  tannin  process. — This  process,  which  has  been 
much  spoken  of,  is  due  to  Major  C.  Russell.  Thanks  to 
the  persevering  and  ingenious  experiments  of  this  sav^ant, 
it  is  now  possible  to  preserve  the  prepared  plates  for  a 
very  long  time  without  their  losing  any  of  their  pro- 
perties. Their  sensibility  is  certainly  much  more  con- 
siderable than  that  of  plates  coated  in  the  ordinary  way. 
Major  Russell's  discovery  consists  in  combining  tannin, 
or  tannic  acid,  with  the  coating  of  iodide  of  silver,  des- 
tined to  be  impressed  with  the  light.  The  original  pro- 
cess, which  was  published  in  1 861,  has  undergone  con- 
siderable modifications  since  that  time  ;  we  shall  describe 
it  with  the  improvements  which  have  been  successively 
made.^ 

*  The  tannin  process  is  here  singled  out  as  a  type  of  a  host  of  other 
dry-plate  processes  which  are  interesting  as  forming  links  in  the  chain  of 
photographic  progress.  An  endless  variety  of  substances  may  be  used  in 
place  of  tannin  more  or  less  successfully.  Thus  I  myself,  when  I  could 
obtain  nothing  better,  have  employed  a  solution  of  lime-juice,  orange-juice, 
and,  with  varying  success,  ordinary  bottled  beer  with  a  slight  admixture 
of  sugar.  But  the  most  modern  processes,  although  they  demand  delicate 
manipulation,  yet  in  their  rapidity  of  action  and  beautiful  results  are 
nearly  on  a  par  with  our  best  wet-collodion  processes.  As  this  work  does 
not  profess  to  furnish  exhaustive  descriptions  of  the  various  processes,  I 
need  do  no  more  than  give  an  outline  of  one  or  two  of  the  newest  methods 
of  preparing  dry  plates,  which  do  away  with  the  use  of  the  nitrate  of 
silver  bath — El). 


PROCESSES.  157 


The  plate  is  first  coated  with  a  special  collodion 
containing  small  quantities  of  iodide  of  cadmium  and 

Gelatino-bromide  process : — 

To  I  ounce  pure  gelatine  add  16  ounces  of  water.  When  the  gelatine 
has  absorbed  the  water  to  its  fullest  extent,  dissolve  by  gentle  heat,  and 
while  the  solution  is  yet  hot  add  i\  ounce  bromide  of  potassium,  stirring 
the  mixture  until  the  salt  is  thoroughly  taken  up.  Dissolve  |  ounce  nitrate 
of  silver  in  water,  sufficient  to  make  a  saturated  solution,  which  must  then 
be  next  added  to  the  bromadised  gelatine.  The  addition  of  the  nitrate  of 
silver  renders  the  solution  highly  sensitive  to  light.  This  and  the  subsequent 
operations  must  therefore  be  conducted  in  the  yellow  non  active  light  of 
the  operating  room.  This  sensitive  emulsion  which  alone  forms  the  dry- 
plate  film  must  be  subjected  to  a  process  of  washing  so  as  to  remove  the 
free  salts  of  the  metals,  which  would  otherwise  interfere  with  the  picture. 
This  may  be  done  by  allowing  the  gelatine  to  set,  cutting  it  up  in  small 
pieces  and  washing  it  in  water  kept  running  for  some  time,  until,  indeed, 
all  traces  of  the  free  salts  have  been  removed,  and  the  emulsion  carries  only 
the  quantity  with  which  it  has  formed  an  intimate  union  in  the  production 
of  bromide  of  silver.  The  sensitised  gelatine  may  now  be  dissolved  by 
gentle  heat,  and  poured  in  quantum  siifficit  on  the  centre  of  a  glass  plate 
over  which  it  is  evenly  distributed,  placed  on  a  level  stand  on  a  dark  shelf 
free  from  dust,  where  it  is  allowed  to  set  and  dry".  When  dry,  the  plate 
thus  prepared  is  ready  for  exposure  in  the  camera,  and  if  carefully  pre- 
served from  daylight  weeks  may  elapse  between  the  time  of  preparation 
and  exposure,  and  exposure  and  development.  I  have  seen  plates  taken  by 
this  method  almost  instantaneously,  but  the  nice  timing  of  the  exposure 
has  hitherto  proved  a  drawback  to  the  wide  application  of  the  process. 
After  exposure  the  plate  must  be  soaked  for  some  time  in  water,  when  the 
latent  image  may  be  brought  out  by  what  is  kno^vn  as  'alkaline  develop- 
ment,' discovered  by  the  inventor  of  the  tannin  process. 

Developer,  No  i. 

Carbonate  of  Soda 40  grains. 

Water Lpint. 

No.   2. 

Pyrogallic  Acid    .......         96  grains. 

Alcohol I  ounce. 


158     OPERATIONS   AND   PROCESSES   OF   PHOTOGRAPHY. 

iodide  and  bromide  of  ammonium.  It  is  sensitised  in  a 
bath  of  nitrate  of  silver  strongly  acid  with  acetic  arid. 
The  plate  as  soon  as  sensitised  is  well  washed,  then 
coated  with  a  solution  of  tannin  (lO  parts  of  alcohol 
and  2^  to  3  of  tannin  to  the  lOO  of  water).  This  solu- 
tion is  poured  over  the  plate  several  times,  which  is  then 
washed  and  dried  in  the  plate  rack.  It  is  hardly  neces- 
sary to  say  that  these  operations  take  place  in  the  dark 
room  ;  when  the  plate  is  dry  it  is  slightly  warmed,  and 
can  then  be  kept  for  a  very  considerable  time. 

The  time  of  exposure  of  these  tannin  plates  varies 
from  about  35  seconds  to  2  minutes.  Before  developing 
the  image,  the  plate  is  dipped  in  a  weak  solution  of 
nitrate  of  silver  till  the  tannin  coating  is  impregnated. 


No.  3, 


•Bromide  of  Potassium 
Water 


5  grams. 
I  ounce. 


No.  I  is  the  alkaline  solution  which  is  used  with  the  addition  of  a  few 
drops  of  Nos.  2  and  3,  in  quantity  sufficient  to  flood  the  plate.  The  time 
of  exposure  and  development  must  be  determined  by  the  experience  of  the 
operator. 

Collodion  Emulsion  process : — 

This  process,  while  it  offers  more  uniformity  and  certainty  in  its  results, 
is  not  so  sensitive  as  that  just  described  in  which  gelatine  takes  the  place  of 
collodion.  With  the  exception  of  collodion,  ihe  materials  used  and  the 
mode  of  manipulating  the  plates  are  almost  identical  with  those  employed  in 
the  gelatino-bromide  process.  The  reader  who  is  anxious  to  study  the 
collodion  emulsion  process  will  find  detailed  descriptions  in  the  British 
yournal  Photographic  Almanac  for  1875. — ■^^- 


PROCESSES.  159 


It  is  then  drained  and  the  picture  developed  with  a  solu- 
tion of  pyrogallic  acid  and  water,  and  a  little  alcohol 
and  glacial  acetic  acid.  If  the  image  requires  intensi- 
fying, a  weak  solution  of  citric  acid  mixed  with  a  small 
quantity  of  nitrate  of  silver  added  to  the  developer  will 
give  excellent  results.  The  plate  is  then  well  washed 
and  fixed  as  usual  with  hyposulphite  of  soda. 

M.  Legray  is  the  inventor  of  the  waxed -paper  pro- 
cess— an  interesting  and  useful  process,  of  which  the 
following  is  a  succinct  description. 

The  paper  which  is  to  be  coated  with  wax  must  be 
formed  of  a  uniform  and  homogeneous  pulp,  well-sized, 
and  must  be  thin,  as  the  proof  has  to  be  seen  by  trans- 
mitted light.  The  operation  of  waxing  is  very  delicate. 
The  paper  is  spread  out  on  a  metal  box  filled  with  boil- 
ing water,  which  is  maintained  at  100°  by  placing  it 
on  a  fire.  The  leaf  of  paper  is  protected  from  con- 
tact with  the  metal  by  intermediate  sheets  of  blotting 
paper ;  it  is  then  rubbed  with  white  wax  which  sinks  in 
as  it  is  spread.  As  soon  as  the  first  leaf  is  well  impreg- 
nated all  over  its  surface,  a  second  sheet  of  paper  is 
placed  on  it,  and  rubbed  with  wax  in  the  same  way,  then 
a  third,  a  fourth,  and  so  on  till  twelve  have  been  done. 
These  twelve  waxed  sheets  are  interleaved  with 
twelve   unwaxed  sheets,  and  then  the  whole  packet  is 


l60     OPERATIONS   AND   PROCESSES   OF   PHOTOGRAPHY. 

energetically  rubbed  first  in  one  direction,  then  in 
another.  The  excess  of  wax  in  the  twelve  sheets 
prepared  passes  into  the  other  twelve  sheets,  thus  giving 
twenty-four  sheets  saturated  with  wax.  Each  leaf  is  now 
rubbed  separately,  one  by  one,  with  a  silk  rubber,  and 
when  a  well-rubbed  leaf  is  smooth,  transparent,  and 
does  not  exhibit  white  or  brilliant  spots,  indicating  a 
want  or  excess  of  wax,  it  can  be  kept  for  an  indefinite 
time. 

The  waxed  papers  thus  obtained  are  plunged  into  a 
solution  of  iodide  of  potassium  in  rice  and  water.^  When 
removed  from  the  bath  and  dried,  they  are  placed  be- 
tween two  sheets  of  blotting  paper,  and  rubbed  warm 
with  a  hot  iron. 

The  iodised  waxed  paper  has  a  violet  tint ;  it  must 
be  preserved  from  contact  with  damp  or  air.  When 
it  is  required  to  sensitise  the  paper  before  use,  it  is 
plunged  in  a  bath  of  nitrate  of  silver  to  which  acetic  acid 
has  been  added.^ 


'  To  35  oz.  of  Water, 

i,ooo  grains  of  Rice. 
750      ,,       ,,     Sugar  of  Milk. 
225      ,,       ,,     Iodide  of  Potassium. 
75      ,,      ,,    Bromide  of  Potassium. 

2  Distilled  Water i  ounce. 

Nitrate  of  Silver 30  grains. 

Glacial  Acetic  Acid 40  minims. 


THE  CARBON    PROCESS.  l6l 

The  paper  is  exposed  in  the  camera  by  being  fixed 
between  two  glass  plates.  The  time  of  exposure  is  usually 
about  one  hour,  sometimes  more ;  it  can  only  be  de- 
termined by  experience. 

The  development  of  the  picture  is  accomplished  by  the 
aid  of  gallic  acid,  to  which  nitrate  of  silver  and  acetic 
acid  are  subsequently  added.  The  leaf  of  paper  is  com- 
pletely immersed  in  the  developing  bath  until  it  has 
acquired  the  desired  intensity. 

It  is  fixed  as  usual  with  hyposulphite  of  soda. 

When  washed  and  dried  the  paper  is  rendered  again 
transparent  by  rubbing  with  a  hot  iron,  after  being 
covered  with  a  piece  of  tissue  paper. 

Besides  M.  Legray,  Messrs.  Vigier,  Baldus,  and  others 
have  prepared  albumenised  and  gelatinised  papers  which 
give  equally  good  results,  and  as  formulae  for  obtaining 
negatives  on  waxed  paper  abound,  we  refer  the  reader 
who  may  be  curious  in  this  regard  to  the  published  works 
of  these  inventors. 

The  permanent  carbon  process.  —The  processes  we 
have  hitherto  described  furnish  prints  more  or  less 
liable  to  fade.  Whatever  the  cares  and  precautions  of 
the  operator,  however  well  it  is  washed,  the  positive 
proof   is    destined    after  a   certain    time  to  tarnish,  to 

M 


1 62     OPERATIONS   AND   PROCESSES   OF   PHOTOGRAPHY 

become  yellow,  and  even  to  disappear.  How,  indeed, 
could  it  be  otherwise,  when  it  is  formed  by  the  reduc- 
tion of  metallic  salts,  made  up  to  a  certain  extent  of 
fugitive  chemical  agents.  This  serious  drawback  gave 
rise  to  the  desire  for  some  means  of  imparting  dura- 
bility to  the  photograph,  and  to  assure  it  the  same  per- 
manency as  typographical  proofs  and  impressions  in 
general  which  are  obtained  with  an  ink  made  with  some 
permanent  basis,  such  as  carbon.  &c. 

The  term  carbon  print  is  applied  to  photographic  im- 
pressions obtained  by  the  aid  of  some  fixed  or  unalterable 
matter,  carbon  or  other  permanent  mineral  substances. 
The  various  processes  for  producing  positive  carbon 
prints  are  based  on  the  principle  indicated  by  Alphonse 
Poitevin  in  1855. 

This  learned  experimentalist,  of  whom  we  shall  have 
to  speak  further  in  our  chapter  on  Heliography,  and  to 
whom  the  photographic  art  is  indebted  for  a  great  num- 
ber of  most  important  improvements,  discovered  that  the 
action  of  light  on  gummy  or  mucilaginous  matters  mixed 
with  alkaline  or  earthy  bichromates  renders  them  in- 
soluble, even  in  warm  water  :  it  then  occurred  to  him,  for 
the  purpose  of  producing  permanent  photographs,  to  add 
some  insoluble  colouring  matters,  such  as  carbon  or  pow- 


CARBON   PRINTING.  163 


dered  enamels,  to  gelatine,  albumen,  gum  arable,  sugar, 
starch,  &c.^ 

A  fine  coating  of  bichromatised  gelatine,  mixed 
with  carbon,  is  spread  over  a  leaf  of  paper  and  exposed 
to  the  impression  of  the  light  through  a  negative.  After 
the  insolation,  the  paper  is  washed  in  tepid  water  ;  the 
parts  of  the  picture  unaffected  by  the  light  {i.e,  those 
parts  which  have  been  protected  by  the  denser  portion 
of  the  negative)  are  dissolved,  whilst  those  parts  which 
have  been  rendered  insoluble  by  the  action  of  light  re- 
main adhering  to  the  surface,  and  the  picture  ^appears, 
formed  by  the  insoluble  parts  of  the  mucilage.  Since 
this  first  indication  of  the  process  by  M.  Poitevin, 
published  more  as  a  curiosity  than  as  a  practical 
method,  a  great  number  of  operators  set  themselves  to 
study  the  new  phenomena  brought  to  light.  Laborde, 
Gamier,  and  Salmon  at  Paris,  Pouncy  at  London,  and 
others,  were  not  long  in-  conceiving  similar  processes  to 
that  of  M.  Poitevin,  all  of  them  more  or  less  perfect.  In 
1864,  Mr.  Swan  gave  a  vigorous  new  start  to  the  art  of 
permanent  carbon  photography  ;  and  shortly  afterwards, 
Mr.  A.  Marion  popularised  the  new  process  by  some 
truly  remarkable  productions. 

'  Photographic  au  charbon.  Recueil  pratique  de  divers  procedes  des 
epreuves  positives  formees  de  substances  inalterables,  par  L.  Vidal.  Paris. 
1869. 

M  2 


1 64     OPERATIONS  AND   PROCESSES  OF  PHOTOGRAPHY. 

The  following  extract  from  the  Moniteur  de  la  Pho- 
tographie  describes  Mr.  Swan's  curious  process  : — '  In  500 
cubic  centimetres  of  cold  water,  allow  1,800  grains  of 
gelatine  to  swell  for  some  hours,  then  dissolve  with  a 
gentle  heat  Add  a  white  of  ^^^  beaten  up,  stir  well 
and  heat  till  it  boils,  and  then  filter.  By  this  means  the 
albumen  is  clarified  and  becomes  brilliant  and  limpid. 
The  amount  lost  by  evaporation  is  made  up  with  water, 
and  900  grains  of  white  sugar  added.  Indian  ink  as 
colouring  matter  is  now  mixed  with  it,  after  being  pow- 
dered or  dissolved  in  water.  The  gelatine  is  kept  in  well 
stoppered  bottles.  To  sensitise  it,  a  solution  of  bichro- 
mate of  ammonia  (450  grains  to  1,350  of  water),  is  pre- 
pared and  added  to  the  coloured  gelatine  in  the  propor- 
tion of  450  grains  to  3,000  or  4,500  grains  of  gelatine.  A 
glass  plate  is  next  coated  with  non-iodised  collodion  of  a 
proper  consistency :  this,  being  evenly  spread  over,  is 
allowed  to  dry  perfectly.  The  plate  is  now  warmed  and 
coated  very  evenly  with  the  sensitised  gelatine  solution, 
which  soon  sets ;  when  quite  dry,  this  film  can  be  detached 
by  passing  a  penknife  along  the  edges,  and  presents  the 
appearance  of  a  piece  of  varnished  leather,  black  in  colour, 
and  flexible.  It  is  nevertheless  translucent,  and  by  exami- 
nation, it  is  easy  to  determine  if  it  is  of  a  proper  colour. 
This  film  must  be  kept  in  the  dark,  and  employed  within 


swan's  process.  165 

one  or  two  days.  To  print  on  it,  it  is  placed  in  contact 
with  the  negative,  the  collodion  side  next  the  film,  so  that 
by  exposure  to  the  light  the  impression  is  formed  on  the 
inner  face  of  the  sensitised  gelatine.  The  time  of  exposure 
naturally  varies  according  to  the  intensity  of  the  light, 
and  the  density  of  the  negative ;  but,  in  any  case,  it  will 
not  exceed  the  third  or  the  fourth  of  that  required  with 
the  nitrates  of  silver.  The  range  is  much  larger  than 
with  the  ordinary  processes,  and  prolonged  exposure 
does  not  materially  affect  the  picture.  The  print  is  then 
mounted  on  paper  with  starch  or  india-rubber.  When 
dry  it  is  plunged  into  water,  heated  to  40°  Centi- 
grade. The  gelatine  unaltered  by  the  light  soon  dis- 
solves, leaving  the  picture  with  all  its  gradations  of  tone 
adhering  to  the  collodion.  When  the  print  has  soaked 
for  about  two  hours  it  can  be  fastened  to  another  sheet 
of  paper,  to  straighten  it,  and  when  dry  the  first  sheet 
may  be  readily  removed.  The  print  when  finished 
possesses  great  delicacy,  and  is  of  course  glazed  with 
the  film  of  collodion  in  front'  ^ 

'  Carbon  prints  taken  by  the  above  process  are  as  fine  in  gradation, 
vigour,  and  sharpness  as  the  best  silver  prints.  There  seems,  however, 
to  be  some  risk  of  their  destruction,  in  consequence  of  the  collodion  film 
cracking.  The  process  is  patented  (No.  503,  February  29,  1864).  Some 
specimens  submitted  to  the  public  by  the  patentee  are  not  inferior  to  the 
very  finest  photographs  upon  paper  that  have  ever  been  seen.  Tht  Dictionary 
of  Photography.     Low  &  Co.  1867. 


1 66     OPERATIONS   AND    PROCESSES   OF   PHOTOGRAPHY. 

Since  Mr.  Swan's  innprovements  the  so-called  carbon 
processes  have  made  great  strides,  and  admirable  results 
have  been  arrived  at.  According  to  the  nature  of  the 
permanent  and  solid  substance  which  is  incorporated 
with  the  gelatine,  the  glazed  tissue  can  be  toned  black 
like  an  engraving,  purple,  or  sepia  colour. 

The  colouring  matter,  of  whatever  nature  it  may  be, 
is  first  ground  to  an  impalpable  powder,  and  the  gelatine, 
dissolved  in  warm  water  and  well  filtered,  is  added  in 
small  doses  (3,000  grains  of  gelatine  to  the  litre  of 
water  =  176  pint).  The  mixture  is  then  stirred  till  per- 
fectly homogeneous. 

A  sheet  of  paper  of  good  quality  is  next  damped 
and  placed  on  a  glass  plate  in  such  a  way  that  by  the 
means  of  four  small  rules  the  four  edges  of  the  paper 
can  be  turned  up  to  the  extent  of  not  more  than  three 
or  four  millimetres,  a  very  shallow  dish  being  thus 
formed,  into  which  the  gelatine  solution  is  poured  so  as 
to  flow  perfectly  horizontally.  The  solution  soon  solidi- 
fies :  the  gelatine  film  is  then  lifted  from  the  glass  and 
allowed  to  dry  spontaneously. 

The  gelatine  films  are  sensitised  by  immersion  in 
an  aqueous  solution  of  bichromate  of  potassium  (of 
5  p.  100).  To  take  an  impression,  one  of  them  is 
applied  to  the  back  of  a  photographic  plate,  and  is  then 


IMPROVEMENTS  IN   CARBON   PRINTING.  1 6/ 


exposed  to  the  light.  When  a  negative  is  used  to  print 
from,  the  picture  will  be  reversed,  and  it  is  for  this 
reason  that  a  provisory  support  should  be  employed, 
which  can  be  easily  taken  from  the  positive  picture 
when  desired.  We  refer  the  reader  who  may  wish  to 
master  all  the  details  of  this  process  to  Mr.  D.  B.  Monck- 
hoven's  work,^  only  allowing  ourselves  to  give  here  the 
principle  of  a  new  branch  of  the  art  which  we  are  study- 
ing. The  practical  details  would  take  us  too  far  from 
our  plan,  which  comprehends  all  the  numerous  chapters 
of  the  book  of  modern  photography.^ 

'  Published  by  G.  Masson.     Paris,  1873. 

"^  The  carbon  process,  in  its  most  recent  fonns,  has  attained  to  that 
degree  of  perfection,  certainty,  and  facility  of  manipulation  which  renders 
it  a  most  formidable  rival  to  silver  printing.  Photographers  have  not 
been  slow  to  acknowledge  its  superiority  over  all  other  processes  in  the 
production  of  the  most  delicately  beautiful  enlargements  from  small  nega- 
tives. But  it  is  only  within  the  past  month  or  two  that  the  carbon  process 
has  proved  capable  of  producing  small  prints  equal  in  every  way  to  the 
best  silver  prints. 

In  common  with  all  the  other  permanent  photographic  printing  processes, 
whether  the  proofs  are  obtained  by  exposure  to  sunlight  or  mechanically, 
the  carbon  process  starts  from  the  basis  supplied  in  the  insolubility  resulting 
from  the  exposure  to  solar  light  of  a  mixture  of  gelatine  and  bichromate  of 
potash.  But  in  order  to  render  this  chemical  action  available  for  the  pur- 
poses of  the  carbon  printer,  the  gelatine  and  bichromate  of  potash  must  be 
charged  with  some  permanent  colour  in  a  fine  state  of  division,  us  in  Swan's 
process.  In  place,  however,  of  employing  collodion  as  the  support  for  the 
tissue,  the  Autotype  Company  at  Ealing  Dean  simplified  the  method 
of  producing  tissue  by  using  paper  as  the  support  and  by  introducing 
machinery  into  its  manufacture.  This  company  held  various  patents  which 
have  been  transferred  to  Messrs.  Spencer,  Sawyer,  Bird  &  Co.,  to  whom 
we  are  mainly  indebted  for  rendering  the  carbon  process  of  practical 


1 68      OPERATIONS  AND   PROCESSES   OF   PHOTOGRAPHY. 


commercial  value.  They  now  manufacture  tissue  of  all  shades  of  colour, 
ready  for  the  simple  operation  of  sensitising  ty  floating  on  a  solution  of 
bichromate  of  potash.  While  confining  my  observations  to  one  or  two 
topics  relating  to  carbon  printing,  I  must  refer  the  reader  for  detailed 
information  to  the  manual  of  practical  instruction  published  by  the  above 
firm. 

A  carbon  print  may  be  taken  from  an  ordinaiy  negative  by  exposing 
the  sensitised  tissue  beneath  the  negative  as  in  ordinary  silver  printing. 
No  visible  image  will  result  from  this  exposure  :  the  image  is  nevertheless 
imprinted  in  the  tissue,  or  rather,  the  light  has  imparted  to  the  surface 
various  degrees  of  insolubility,  which,  in  their  intensity,  correspond  exactly 
with  the  shadows  and  half-tones  of  the  picture.  In  other  words,  where 
the  action  of  the  light  is  strongest,  the  sensitive  film  elects  to  form  a  close 
and  indissoluble  union  with  the  carbon.  ,  When  the  light  has  only  partially 
affected  the  tissue  the  union  is  weak,  and  it  readily,  when  treated  with 
warm  water,  yields  up  part  of  the  colouring  matter,  and  where  the  light  has 
not  exercised  its  subtle  influence  in  the  faintest  degree,  the  colouring  matter 
may  be  dissolved  out,  leaving  the  paper  white. 

The  printing  of  the  picture  must  be  timed  by  the  use  of  a  simple 
actinometer  made  for  the  purpose.  In  order  to  develop  the  print  it  is 
necessary  to  immerse  the  tissue  in  a  bath  of  water  and  to  place  it  in  intimate 
contact  with  a  sheet  of  transfer  paper.  The  tissue  and  its  new  support  are 
then  laid  in  a  bath  of  tepid  water,  when  the  original  support  will  float  off 
and  the  picture  gradually  reveal  itself.  This  simple  operation  of  washing  with 
water  removes  all  the  free  unaltered  carbon,  and  leaves  a  bright  and  beautiful 
impression  on  a  permanent  support.  In  the  case  of  negatives  which  are 
not  reversed,  a  double  transfer  must  be  effected  by  placing  the  tissue  for 
development  on  a  temporary  support  of  glass  or  zinc.  Specially  prepared 
tissue,  mounted  and  developed  on  a  glass  plate,  not  only  produces  a  trans- 
parency full  of  the  most  beautiful  gradations  of  light  and  shade,  but  so 
exceedingly  minute  in  its  details  as  to  enable  the  operator  to  take  from  it  a 
perfect  negative,  enlarged  to  three  or  four  times  the  diameter  of  the 
original.  I  know  of  no  other  transparency  to  be  compared  with  it  in  the 
making  of  large  negatives  from  small  ones. 

This  peculiar  adaptability  of  the  carbon  transparency  for  copying  or 
enlarging  negatives  has  rendered  it  of  the  greatest  value,  as  it  enables  the 
carbon  printer  to  make  a  reversed  negative  so  absolutely  identical  with  the 
original  as  to  permit  him  to  print  his  proofs  by  single  transfer.  — Ed. 


169 


CHAPTER   VIII. 

PROBLEMS   TO   BE   SOLVED. 

THE  FIXING  OF  COLOURS — A  MYSTIFICATION — EDMOND  BECQUEREL'S 
EXPERIMENTS  —  ATTEMPTS  OF  NIEPCE  DE  SAINT-VICTOR  AND 
POITEVIN— PHOTOGRAPHIC    PRINTING. 

We  have  seen  how  and  by  what  processes  th(?  photo- 
graphic art  arrived  at  fixing  the  image  of  the  camera  on 
paper :  the  results  obtained,  though  marvellous  as  they 
are,  are  susceptible  of  being  improved,  like  all  human 
work.  We  think  it  will  be  interesting  if  we  glance  at 
some  of  the  improvements  which  it  is  possible  to  hope 
for  in  a  near  future. 

Photography  reproduces  nature ;  the  picture  which  it 
furnishes  is  the  image  of  the  mirror,  but  the  image  with- 
out colour.  To  find  a  photographic  process  susceptible 
of  giving  coloured  proofs,  and  capable  of  reproducing 
the  colours  as  it  does  the  aspect  and  form  of  natural 
objects,  would  seem  to  be  the  criterion  of  photographic 
power  :  on  the  face  of  it,  the  problem  appears  insoluble. 
It  is  not  necessary  to  be  versed  in  the  study  of  physics 


170     OPERATIONS   AND   PROCESSES   OF   PHOTOGRAPHY. 


to  understand  the  difficulties  in  the  way.  It  is  necessary 
to  find  a  substance  which  should  be  influenced  in  dif- 
ferent ways  by  the  different  rays  of  the  spectrum,  and 
which  could  reproduce  the  proper  colour  of  each 
luminous  ray  ;  the  search  for  such  a  chemical  as  this 
would  seem  to  be  comparable  to  that  for  the  philoso- 
pher's stone.  However,  in  the  presence  of  certain  facts 
already  obtained  by  some  savants  of  note,  it  would  be 
imprudent  to  deny  the  possibility  of  such  a  problem  ;  its 
solution  is  perhaps  nearer  than  we  are  in  the  habit  of 
supposing.  A  few  lights  are  already  shining  in  the 
direction  of  this  goal,  hidden  in  the  bosom  of  the 
unknown.  Will  they  be  useful  or  fruitless  ?  Will  they 
open  up  a  new  road  or  remain  isolated  and  sterile } 
Until  we  have  passed  in  review  the  results  already 
obtained  we  cannot  reply. 

It  may  be  well,  before  studying  the  real  experiments 
made  by  some  of  our  most  eminent  scientific  men,  to  nar- 
rate one  or  two  facts,  interesting  from  an  historical  point 
of  view,  which  made  a  great  stir  at  the  time.  In  185 1,  the 
photographers  of  Europe  were  all  thrown  into  a  state  of 
excitement  by  an  extraordinary  announcement  which 
came  from  the  other  side  of  the  Atlantic.  The 
American  papers  affirmed  that  a  Mr.  Hill,  a  photo- 
grapher, had  discovered  the  means  of  reproducing  the 


PHOTOGRAPHS   IN   COLOUR.  171 


images  of  the  camera  with  their  natural  colours.  For  the 
time  nothing  was  spoken  of  but  this  illustrious  inventor, 
and  for  the  moment  his  name  became  as  renowned  as 
that  of  Daguerre.  This  Mr.  Hill  was  a  reverend  pastor 
who  was  no  enemy  to  puffing  :  he  had  launched  the 
news  of  his  invention  in  all  the  American  papers,  and 
had  nothing  to  complain  of  in  the  enthusiastic  epithets 
which  were  applied  to  his  discovery.  Mr.  Hill,  all  at 
once,  soared  like  a  rocket  to  the  topmost  steps  of  the 
ladder  of  fame.  The  cute  pastor  allowed  public  curiosity 
to  ferment  well.  '  When  he  saw  things  were  ripe,'  says 
Mr.  Alexander  Ken,  who  relates  the  story,  *  he  issued  a 
circular  promising  shortly  to  publish  a  work  which 
should  divulge  the  secrets  of  his  discovery.  The 
author  added  that  this  work  would  only  be  circulated  to 
the  extent  subscribed  for  by  photographers,  and  that 
it  would  be  forwarded  to  all  those  who  sent  him  their 
address  with  five  dollars.  A  testimonial,  signed  by 
several  persons,  set  forth  that  Mr.  Hill  was  a  respectable 
ecclesiastic  worthy  of  all  confidence. 

'  The  circular  produced  fifteen  thousand  dollars.  The 
volume  appeared :  it  consisted  of  about  one  hundred 
pages,  and  cost  the  author  about  twopence  a  copy.  But 
if  it  was  dear,  it  contained  nothing  but  a  few  common- 
place   descriptions    of    the   well-known  daguerreotype 


172     OPERATIONS   AND   PROCESSES   OF    PHOTOGRAPHY. 

process,  and  said  not  a  word  about  the  reproduction  of 
colours  ! '  * 

Mr.  Hill  afterwards  published  a  second  and  a 
third  brochure,  but  the  public  had  had  enough  of  Mr. 
Hill  and  his  works.  The  subscribers  swore,  but  a  little 
too  late,  that  they  would  not  take  them. 

M.  Edmond  Becquerel  was  the  first  who  reproduced 
the  image  of  coloured  rays.  He  succeeded  in  printing 
the  seven  colours  of  the  solar  spectrum  on  a  silver  plate. 
His  works  when  made  known  were  appreciated  at  their 
real  value  by  men  of  science.  M.  Becquerel  plunged  a 
plate  of  silver  in  hydrochloric  acid  diluted  with  water  ; 
he  attached  the  metal  to  the  wire  of  an  electric  battery. 
Under  the  influence  of  the  electric  current  the  silver  be- 
came coated  with  sub-chloride  of  silver,  of  a  characteristic 
rose  colour.  On  being  taken  from  the  bath,  washed  and 
dried,  it  was  sufficient  to  expose  it  to  the  rays  of  the  solar 
spectrum  :  the  seven  colours  were  then  delineated,  with 
their  corresponding  gradations.  Unfortunately,  up  to  the 
present  no  means  have  been  discovered  for  fixing  these 
colours  :  they  disappear  when  exposed  to  daylight,  and 
must  be  preserved  in  the  dark. 

'  M.  Niepce  de  Saint- Victor  also  attempted  to  solve 
this  great  problem  of  the  fixation  of  colours,  but  he-was 

'  Dissertation  on  PJwtography.     A.  Ken.    1864. 


PHOTOGRAPHS   IN   COLOUR.  1 73 

foiled  in  his  attempts.  He  succeeded,  however,  in 
obtaining  photographic  proofs  of  blue,  red,  and  green 
colour.  These  coloured  photographs  have  a  very  pretty 
effect.  Although  somewhat  more  stable  than  formerly, 
they  are  still  affected  by  prolonged  exposure  to  light : 
the  processes  are,  however,  already  much  improved,  for 
the  proof  which  M.  Niepce  obtained  at  the  commence- 
ment of  his  researches  could  not  stand  the  slightest  ex- 
posure to  daylight.  It  is  due  to  the  employment  of 
salts  of  uranium  that  it  has  been  possible  to  solve  this 
interesting  question. 

'To  obtain  a  red-coloured  proof,  for  example,  he 
prepared  the  paper  with  a  solution  of  azotate  of  uranium 
of  20  to  the  100  of  water:  this  paper  is  dried  in  the 
dark,  and  exposed  for  a  time,  varying  in  length  accord- 
ing to  the  intensity  of  the  light ;  the  proof  is  then  washed 
in  water  of  50°  or  60°  Centigrade,  and  subsequently 
dipped  into  a  solution  of  cyanoferride  of  potassium  of  2 
to  100.  After  a  few  minutes  the  print  assumes  a 
beautiful  blood-red  colour ;  it  only  remains  to  wash  it 
well  in  water  several  times  changed  and  dry  it.  The 
red  print  thus  obtained  becomes  green  if  dipped  in  a 
solution  of  azotate  of  cobalt,  and  not  washed  ;  the 
green  colour  appears  by  drying  at  a  fire  ;  it  is  fixed  by 
immersion  for  a  few  seconds  in  a  solution  of  sulphate  of 


174     OPERATIONS   AND   PROCESSES   OF   PHOTOGRAPHY. 


iron  and  sulphuric  acid,  each  in  proportion  of  4  to 
the  100  of  water ;  it  is  then  well  washed  and  dried 
at  the  fire.  A  violet  colour  may  be  obtained  by  washing 
in  warm  water  as  soon  as  taken  from  the  printing  frame, 
and  by  developing  with  chloride  of  gold  of  ^  to 
the  100  of  water.  To  obtain  blue  prints  the  paper  is 
prepared  with  a  solution  of  cyanoferride  of  potassium  of 
20  to  the  100  of  water  ;  after  exposure  under  the  nega- 
tive it  is  washed  for  ten  seconds  with  a  solution  of 
bichloride  of  mercury,  saturated  cold ;  a  solution  of 
oxalic  acid  at  60°  is  next  applied,  and  the  print  is  then 
well  washed  and  dried.' ' 

In  1866  M.  Poitevin  made  a  series  of  curious  experi- 
ments relating  to  the  grand  problem  of  fixing  colours. 
*  On  a  paper  covered  previously  with  a  coating  of  violet 
chloride  of  silver,  which  he  had  obtained  by  exposing 
white  chloride  to  the  light,  and  in  presence  of  a  reducing 
salt,  a  liquid  is  applied  formed  of  a  volume  of  saturated 
solution  of  bichromate  of  potassium,  a  volume  of  satu- 
rated solution  of  sulphate  of  copper,  and  a  volume  of 
solution  of  5  to  the  100  of  chloride  of  potassium  ;  the 
paper  thus  prepared  is  allowed  to  dry,  and  must  be  kept 
away  from  light.  The  bichromate  of  potassium  may  be 
replaced  by  chromic  acid,  or  by  azotate  of  uranium. 

'  Annuaire  scientifique  de  M.P.P.     Deherain.   Paris.    1862. 


PHOTOGRAPHS  IN   COLOUR.  I 75 

With  this  paper,  which  is,  so  to  speak,  super  sensitised,  the 
exposure  to  the  direct  action  of  the  light  is  not  more 
than  from  five  to  ten  minutes  when  it  takes  place 
through  paintings  on  glass,  and  one  can  very  well  follow 
the  appearance  of  the  image  in  colour.  This  paper  is 
not  sufficiently  impressionable  to  allow  of  its  employ- 
ment in  the  camera ;  but,  such  as  it  is,  it  gives  coloured 
reproductions  in  a  special  enlarging  apparatus,'  '  - 

These  photochromos  may  be  preserved  in  an  album, 
if  the  precaution  is  taken  of  washing  them  first  in  water 
acidulated  with  chromic  acid,  then  in  water  containing 
bichloride  of  mercur>^  again  in  water  charged  with  ni- 
trate of  lead;  and  finally  in  pure  water.  In  this  state, 
they  will  remain  unaltered  if  kept  from  the  light. 

'  The  problem  of  obtaining  polychromatic  photographs  is  still  far  from 
being  solved.  More  enthusiasts  than  one  have  imagined  that  they  have 
discovered  a  clue  to  the  mystery  in  the  beautiful  prismatic  colours  produced 
by  a  thin  film  of  air  imprisoned  beneath  the  collodion  of  an  imperfectly 
cleaned  plate.  Some  eight  or  ten  years  ago  these  aspirants  to  fame  used 
to  write  to  the  photographic  journals,  proudly  refusing  to  confide  in  the 
public  until  they  had  taken  such  steps  as  would  enable  them  to  engross  to 
themselves  the  entire  credit  of  their  discoveries. 

Monochrome  photographs  may  be  obtained  in  a  variety  of  ways,  but 
such  prints,  unfortunately,  bring  us  no  nearer  to  photography  in  natural 
colours.  M.  Vidal's  prints  were  probably  similar  to  some  I  have  seen  in 
Paris,  produced  by  an  ingenious  mechanical  trick  which  the  photographer 
was  in  no  way  careful  to  conceal. 

As  far  back  as  1810  Seebeck  discovered  that  chloride  of  silver,  when 
subjected  to  the  rays  of  the  spectrum,  partook  slightly  of  the  different 
colours.  Violet  produced  brown,  blue  a  shade  of  blue,  yellow  preserved 
the  paper  white,  and  red  imparted  a  red  tint  to  the  chloride  of  silver.  -  Ed. 


176     OPERATIONS  AND   PROCESSES  OF   PHOTOGRAPHY. 

Unfortunately,  these  new  photogenic  pictures  are 
hardly  more  stable  under  the  action  of  light  than  those 
obtained  previously  by  Messrs.  Becquerel  and  Niepce 
de  Saint- Victor.^ 

In  the  photographic  exhibition  in  the  Palais  de  I'ln- 
dustrie  in  1874,  a  number  of  polychromic  prints  were 
exhibited  by  M.  Vidal,  which  have  the  advantage  of 
being  permanent.  But  the  colours  affect  principally 
the  shadows,  and  are  almost  invisible  in  the  details.  M. 
Vidal  employs  papers  which  he  superposes  to  give  birth 
to  each  colour ;  but  the  tints  and  half-tones  are  very 
indefinite. 

The  result  of  these  curious  experiments  shows  plainly 
that  the  fixation  of  colours  by  photography  is  one  of  the 
most  difficult  problems  which  modern  science  has  to 
solve.  Though  but  a  very  short  portion  of  the  road 
towards  the  great  end  has  been  opened  up,  still  it 
would  be  wrong  to  despise  what  has  been  done  or  to 
regard  the  final  solution  as  an  altogether  Utopian  or 
chimerical  problem. 

As  M.  Niepce  de  Saint- Victor  says,*  If  the  problem  of 
the  fixation  of  colours  is  not  yet  solved,  one  may,  at 
least,  hope  that  it  will  be.' 

'  Louis  Figuier,  Les  Mcrveilles  de  la  Scietue. 


PHOTOGRAPHS  IN   COLOUR.  1 77 

This  is  evidently  one  of  the  greatest  questions  the 
art  of  Daguerre  has  to  solve.  There  is  another  of  high 
import,  namely,  the  transformation  of  the  negative  into 
an  engraving  plate  ;  we  shall  refer  to  this  in  the  first 
pages  of  our  third  part. 


N 


179 


PART    III. 

THE  APPLICATIONS  OF  PHOTOGRAPHY. 


CHAPTER    I. 

HELTOGRAPHY. 

THE  DAGUERREOTYPE  PLATE  TRANSFORMED  INTO  AN  ENGRAVING 
PLATE — DONN6 — FIZEAU  —  THE  PHOTOGRAPHIC  ENGRAVING  OF 
NIEPCE  DE  SAINT  VICTOR —PHOTO-LITHOGRAPHY  AND  HELIOGRAPHY' 
INVENTED  BY  A.  POITEVIN — PROCESSES  OF  BALDUS,  GARNIER,  ETC. — 
THE  AI.BERTYPE — OBERNETTER'S  PROCESS— MODERN  HELIOGRAPHY. 

From  the  origin  of  photography,  even  in  Daguerre's  time, 
it  had  been  a  matter  of  regret  that  the  beautiful  picture 
produced  by  Hght  at  the  focus  of  the  camera  was  con- 
demned to  remain  as  an  unique  type  ;  it  was  asked  if 
the  art  would  not  eventually  be  able  to  produce  from  the 
'negative  an  engraved  plate  capable  of  t)eing  used  for 
printing  on  paper  in  the  ordinary  way.     At  the  present 

'  Foi  a  description  of  the  modem  Hdiotype  Process^  which  is  success- 
fully worked  by  the  Heliotype  Company  of  London,  see  Appendix. 

N  2 


l8o  THE   APPLICATIONS   OF   PHOTOGRAPHY. 

day  these  hopes  have  been  in  part  realised  ;  if  it  has  not 
yet  arrived  at  the  degree  of  perfection  which  will  most 
probably  be  characteristic  of  heliography  in  a  near 
future,  it  has  yet  been  found  possible  to  change  the 
negative  into  a  metallic  plate  similar  to  that  used  by 
the  engraver  on  steel  or  wood. 

It  was  the  noted  savant  M.  Donne  who  first  enter- 
tained the  idea  of  acting  on  a  daguerreotype  plate  with 
hydrochloric  acid,  so  as  to  'bite'  the  negative  in  the 
light  parts,  and  to  leave  the  shadow  and  half-tones 
in  different  degrees  of  relief,  and  thus  to  produce  a 
plate  capable  of  giving  prints  on  paper  in  the  com- 
mon printing-press.  But  the  mercury  employed 
in  the  daguerreotype  process  is  not  always  equally 
distributed  over  the  silvered  copper-plate,  and  it  is 
often  only  of  an  extraordinary  thinness,  so  that  the 
parts  etched  by  the  acid  are  so  extremely  shallow  as 
to  give  but  very  insufficient  relief  to  the  rest ;  besides 
which,  the  parts  left  in  relief  being  formed  of  silver,  a 
very  soft  metal,  allows  but  a  limited  number  of  im- 
pressions being  taken.  The  early  heliotype  plates  were 
worn  out  and  useless  before  fifty  prints  on  paper,  and 
these  still  very  imperfect,  had  been  taken  from  them. 

Fizeau  improved  this  rudimentary  process,  but  he  so 
complicated  the  operations  as  to  make  his  method  prac- 


HELIOGRAPH  Y.  l8l 


tically  useless.  He  succeeded  in  attacking  the  shadows 
and  darker  parts  of  the  daguerreotype  plate,  whilst 
leaving  the  whites  formed  by  the  mercury  in  relief  But 
the  chief  essential  in  a  good  engraving  is  depth  in  its 
reliefs  ;  the  grooves  and  cavities  opened  by  the  acid  must 
be  deepened.  Fizeau  effected  this  in  the  following  way  : 
he  filled  the  grooves  and  hollows  with  a  greasy  oil,  which 
did  not  adhere  to  the  parts  of  the  plate  in  relief  The 
latter  he  gilded  with  a  battery,  and  then  removed  the 
oil  contained  in  the  groov^es,  and  by  aid  of  nitric  acid 
the  latter  could  now  be  made  as  deep  as  desired,  the 
salient  parts  of  the  plate  being  protected  by  their 
covering  of  gold. 

After  these  ingenious  labours  of  Fizeau,  photography 
on  paper  was  discovered,  and  heliography  seemed  likely 
to  lose  its  interest.  It  was  not  long,  however,  before  this 
problem  of  photographic  engraving  was  recognised  as 
worthy  in  all  respects  of  fixing  the  attention  of  enquirers. 
It  is  true  that  by  the  process  of  photographic  printing 
on  paper  one  has  at  once  a  negative  on  glass  which  will 
produce  any  quantity  of  proofs ;  but  how  slow  is  the 
printing !  what  numerous  obstacles  there  are  in  the  way 
of  this  process,  which  requires  sunlight  and  careful 
attention  to  minute  detail  unknown  in  the  production  of 
printing-press  proofs  !  and  besides,  photography  on  paper 


1 82  THE   APPLICATIONS   OF   PHOTOGRAPHY. 

is  not  durable ;  it  fades  with  time,  sometimes  turns 
yellow,  and  often  even  becomes  completely  effaced. 

Photographic  engraving  was  again  studied  with  ac- 
tivity. Talbot  and  Niepce  de  Saint  Victor  succeeded 
in  engraving  transparent  objects  on  steel  by  the  aid  of 
photography.  They  employed  bichromate  of  potassium 
as  their  sensitising  agent ;  but  their  results  were  coarse 
and  devoid  of  all  artistic  value. 

In  1853  M.  Niepce  de  Saint  Victor  published  a 
method  of  transferring  a  photographic  negative  on  to 
steel,  based  on  the  first  process  of  his  relative,  Nicephore 
Niepce. 

His  method  was  as  follows : — A  steel  plate  well 
cleaned  and  polished  is  covered  with  a  coating  of  bitumen 
of  Judea,  which  is  spread  on  the  metal  by  being  previously 
dissolved  in  essence  of  lavender.^ ,  This  coating  is  dried 
in  the  dark  room,  so  as  not  to  be  affected  by  light.  That 
done,  a  glass  positive  is  applied  to  the  metal  plate  thus 
sensitised,  and  the  whole  is  exposed  to  the  light,  which 
acts  on  the  bitumen  through  the  transparent  parts  of  the 
positive.  The  exposure  must  be  continued  for  about 
fifteen  minutes.     The  glass  plate  is  then  taken  off  the 

'  According  to  Mr.  Monckhoven,  the  bitumen  of  Judea  or  asphaltum 
best  for  these  operations  should  be  completely  insoluble  m  water  ;  it  should 
dissolve  in  the  proportion  of  5  to  the  100  in  alcohol,  of  70  to  the  100  in  ether, 
and  entirely  in  essence  of  turpentine,  in  pure  benzine,  and  in  chloroform. 


HELIOGRAPHY.  1 83 


steel,  and  the  latter  with  its  coating  of  bitumen  is 
washed  in  a  mixture  of  benzine  and  naphtha  oil,  which 
dissolves  only  those  parts  of  the  coating  which  were  pro- 
tected from  the  action  of  the  light  by  the  opaque  parts 
of  the  photographic  positive. 

The  parts  of  the  steel  plate  laid  bare  by  the  solvent 
can  be  bitten  in  with  nitric  acid,  and  the  rest  being  thus 
left  in  relief,  the  plate  may  be  used  for  printing  with  ink 
on  paper,  and  produces  an  exact  copy  of  the  photograph. 
These  engravings  of  Niepce  de  Saint  Victor  were  not 
without  a  certain  merit,  but,  on  the  other  hand,  they  pos- 
sessed grave  defects ;  the  shadows,  particularly,  present  no 
gradation  or  detail,  being  mere  uniform  blots  which  con- 
verted the  engraving  into  little  more  than  a  coarse  out- 
line. It  was  in  vain  that  M.  de  Saint  Victor  endeavoured 
to  improve  his  process ;  he  shortened  the  exposure  and 
took  impressions  direct  on  to  the  steel  plate  by  means  of 
the  camera,  but  all  to  no  purpose,  and  after  years  of 
persevering  research  he  was  unable  entirely  to  overcome 
the  difficulties  in  his  way. 

Whilst  M.  Niepce  de  Saint  Victor  was  thus  attempt- 
ing the  solution  of  his  difficult  problem,  M.  Poitevin,  an 
engineer  of  note,  of  whom  we  have  already  spoken, 
opened  up  new  and  unexpected  horizons  in  the  domain  of 
photographic  engraving.      Since  1839,  Poitevin,  struck 


1 84  THE   APPLICATIONS   OF   PHOTOGRAPHY. 

with  the  report  read  by  Arago  on  the  fixation  of  the  image 
of  the  camera,  had  been  an  ardent  disciple  of  Daguerre  ; 
but  his  work  as  an  engineer  prevented  him  from  imme- 
diately occupying  himself  with  the  study  of  the  interest- 
ing problems  which  he  hoped  ultimately  to  solve.  *  In 
1842,'  says  Poitevin,  'whilst  experimenting  with  elec- 
trotypy  for  reproducing  the  images  formed  on  the  silver 
plates,  I  had  observed  that  the  daguerreotype  plate,  on 
being  taken  from  the  mercury  fuming  box,  and  bearing 
on  its  surface  the  representation  or  image  of  which  the 
whites  were  formed  by  the  amalgam  of  silver,  and  the 
blacks  by  the  iodide  of  silver  unaltered  by  the  light,  re- 
ceived a  deposit  of  copper  on  the  white  parts  only,  with- 
out the  blacks  or  shadows  being  affected,  when  plunged 
in  the  electrotyping  bath  ;  of  this,  which  was  my  first 
discovery,  I  made  repeated  trials,  all  of  which  succeeded  ; 
but,  forced  to  suspend  these  distractions  (for  at  that 
period  they  were  nothing  more  to  me),  and  devote  my- 
self to  my  career  of  engineer,  it  was  not  until  1847  that 
I  was  enabled  to  take  them  up  again  as  serious  studies. 
I  applied  my  observations  on  engraving  with  acids  to  the 
transferring  on  metal  of  the  ioduretted  designs  of  M. 
Niepce  de  Saint  Victor,  then  to  daguerreotype  images  on 
double  silvered  plates,  and  soon  after  to  the  transforma- 
tion of  daguerreotypes  into  negatives  capable  of  being 


HELIOGRAPHY.  1 85 


used  for  printing  in  the  ordinary  way  on  papers  sensi- 
tised with  nitrate  of  silver. 

During  twenty  years  Poitevin  laid  the  first  founda- 
tions of  several  distinct  methods,  all  of  which  have  their 
originalities  and  applications.  These  processes  were  for 
a  long  time  very  little  known,  but,  happily  for  science, 
the  inventor  at  the  end  of  his  career  decided  to  pub- 
lish all  the  methods  which  he  employed  in  a  brochure, 
which  is  now  very  rare,  entitled  '  Treatise  on  Photo- 
graphic Impression  Without  Nitrate  of  Silver.'  *  This 
brochure,'  as  one  of  his  biographers  truly  says,  '  is  not  a 
manual,  nor  a  treatise,  nor  a  book  ;  it  is  more  than  all 
this  :  it  is  the  resume  of  the  persevering  studies  of  a  man 
who,  knowing  many  things,  for  twenty  years  applied  all 
his  knowledge  to  the  realisation  of  a  single  object — the 
progress  of  an  art  which  he  loved  passionately,  and  of 
which  from  the  commencement  he  understood  the  true 
destiny.' 

The  first  method  worked  out  by  the  clever  operator, 
which  may  be  called  the  galvanoplastic  or  electrotype 
method,  is  as  follows. 

A  photograph  is  taken  by  the  daguerreotype  process. 
When  the  picture  has  been  developed  with  the  mercury 
fumes,  without  removing  the  unaltered  iodide  of  silver, 
the  plate  is  attached  to  the  negative  pole  of  an  electric 


1 86  THE   APPLICATIONS   OF   PHOTOGRAPHY. 

battery,  and  plunged  in  the  electrotype  bath.  The  de- 
posit of  copper  takes  place  only  on  those  parts  of  the 
plate  which  are  not  protected  by  the  non-conducting 
coating  of  iodide  of  silver. 

This  operation  finished,  the  plate  is  next  washed  in  a 
solution  of  hyposulphite  of  soda,  which  removes  the 
iodide  of  silver,  and  lays  bare  the  metallic  silver  beneath. 
In  the  electro  thus  obtained  the  lights  of  the  picture 
are  covered  with  copper,  the  shades  are  formed  by  the 
silver  of  the  plate.  The  plate  is  then  gently  heated  to 
oxidise  the  copper,  and  quicksilver  is  spread  over  it. 
The  liquid  metal  amalgamates  only  with  the  silver,  leav- 
ing the  oxide  of  copper  bare.  Next  the  plate  is  covered 
with  gold  leaf,  and  the  same  phenomenon  is  reproduced  ; 
the  gold  adheres  only  to  the  amalgamated  parts,  which,  it 
must  be  remembered,  represent  the  shades  of  the  picture. 
The  lights  still  remain  indicated  by  the  oxide  of  copper. 
This  partial  gilding  of  the  plate  being  accomplished,  it 
only  remains  to  subject  the  plate  to  nitric  acid  or  aquafor- 
tis ;  the  acid  attacks  the  plate  wherever  it  is  unprotected 
by  the  gold  coating.  By  this  means  the  shades  of  the 
picture,  represented  by  the  gold-coated  parts,  are  left  in 
relief,  and  thus  a  plate  is  produced  capable  of  being  used 
for  typographic  printing. 

After  the  first  attempts  Poitevin   directed   his  ex- 


HELIOGRAPH  Y.  1 8/ 


periments  in  quite  a  new  direction  ;  he  transferred  the 
photographic  proofs  not  now  to  metal  but  to  stone,  and 
his  ingenious  method  was  invented  under  the  name  of 
photo-lithography. 

Photo-lithography. — On  a  stone  of  good  grain 
and  quahty,  Poitevin  spread  a  mixture  of  albumen  and 
bichromate  of  potassium.  He  placed  on  this  surface  a 
photographic  glass  negative,  and  then  exposed  the  whole 
to  the  light.  The  light,  as  we  have  already  explained, 
only  acts  through  the  transparent  parts  of  the  negative. 
By  this  means,  that  is,  by  the  mysterious  influence  ex- 
erted by  the  light  on  the  gelatinous  or  gummy  bichromate 
coating,  the  stone  is  made  capable  of  retaining  printing 
ink.  As  soon  as  the  glass  negative  is  removed,  the 
surface  is  moistened  with  water,  an  inking  roller  is 
passed  over  the  stone,  and  the  ink  only  adheres  to  those 
parts  of  the  coating  on  its  surface  which  have  been 
acted  upon  by  the  light.  The  original  photograph  thus 
becomes  a  lithographic  stone. ^ 

'  See  Poitevin's  work,  '  Photographic  Impression  Without  Nitrate  of 
Silver.'    Paris  1862, 

\Ve  will  complete  this  summary  description  with  the  following  passage, 
extracted  from  the  report  of  the  photographic  commission  charged  to  exa- 
mine the  photo-lithographic  process  : — 

'  If  an  ordinary  lithographic  stone  is  covered  with  an  albuminous  solu- 
tion mixed  with  bichromate  of  potash,  and  if  this  liquid  is  allowed  to  dry 
spontaneously,  the  albumen,  however  much  it  may  be  altered  in  its  nature, 
is  not  in  its  solubility,  and  a  simple  washing  in  ^^•arm  water  is  sufficient  to 


1 88  THE   APPLICATIONS   OF   PHOTOGRAPHY. 


The  discovery  of  this  singular  fact,  which  established 
photo-lithography,  is  certainly  one  of  the  most  remark- 
able made  by  Poitevin,  but  this  clever  experimentalist 
did  not  rest  content  at  this  point.  He  soon  discovered 
that  his  gelatinous  bichromate  of  potash  coating  loses  its 
properties  of  swelling  when  it  has  been  submitted  to  the 
action  of  light.  The  impressioned  film,  treated  with  water, 
under  special  conditions  swells  slightly  in  the  parts  which 
the  light  has  not  acted  on  ;  while  it  remains  unaltered  in 
those  parts  where  the  light  has  acted.    Here  then  was  a 

remove  from  the  stone  the  greater  part  of  the  unaltered  matter  which  has 
been  unable  to  penetrate  it.  But  if  the  surface  thus  prepared  is  exposed  to 
the  action  of  light  through  the  unequally  transparent  parts  of  a  negative, 
a  change  takes  place  which  is  certainly  not  an  ordinary  coagulation,  and  to 
which  the  oxidation  of  the  chromic  acid  doubtless  contributes,  by  rendering 
the  albumen  insoluble,  and  causing  it  to  remain  on  the  stone  in  quantities  the 
larger  the  more  intense  the  exposure  to  the  light  has  been.  Thus  changed, 
the  albumen  resists  water  as  if  it  were  a  greasy  or  fatty  substance.  In  this 
state  it  readily  absorbs  an  ordinary  greasy  ink,  which  does  not  adhere  to 
the  portions  of  the  stone  where  the  light  has  not  acted,  so  that,  if  a  roller 
charged  witji  an  ink  containing  soap,  which  lithographers  call  transfer  or  re- 
printing ink,  is  parsed  over  the  stone  the  ink  adheres  only  to  the  albumenised 
parts  of  the  surface,  and  the  latter  is  thus  coated  with  a  greasy  ink  distri- 
buted in  varying  proportions  of  an  ordinary  drawing.  The  excess  of  ink  is 
removed  by  acidulation  and  damping  with  a  sponge.  The  drawing  is  made 
level  by  being  submitted  to  the  ordinary  lithographic  operations,  that  is  to 
say,  the  removing  of  the  colour  with  essence  of  volatile  oil  and  the  re-inking 
with  the  roller ;  and  nothing  further  remains  but  to  cover  the  stone  thus 
prepared  with  a  coating  of  gum  which  only  adheres  where  there  is  no  ink,  and 
to  submit  it  to  ordinary  inking  and  to  acidulation,  to  be  enabled  to  obtain 
from  it  as  many  copies  as  if  the  drawing,  which  has  been  entirely  made  by 
the  light,  had  been  made  in  the  ordinary  lithographic  manner.  Such  is 
M.  Poitevin's  method.' 


HELIOGRAPHY.  1 89 


substance  which  offered  an  unequal  surface,  the  reHefs 
and  depressions  of  which  corresponded  to  the  h'ghts  and 
shades  of  the  photograph ;  there  was  therefore  nothing 
to  hinder  an  electrotype  being  cast  in  copper  from  it,  and 
the  result  would  be  an  engraved  plate  capable  of  being 
printed  from  in  the  usual  way.  It  is  hardly  necessary 
to  say  that  we  give  here  only  the  principle  of  Poite- 
vin's  process,  which,  in  practice,  requires  extreme  care. 
This  principle  was  essentially  ingenious,  and  capable 
of  giving  results  which,  if  not  perfect,  were  at  least 
satisfactory.  Poitevin  must  be  regarded  as  the  founder 
of  modern  heliography,  his  work  being  the  germ 
of  almost  all  the  mechanical  printing  processes  now 
known. 

Photo-lithography  has  long  been  used  with  advan- 
tage ;  we  shall  see  that  it  was  the  basis  of  photoglypty, 
the  actual  results  of  which  are  so  remarkable.  It  gained 
for  its  inventor  the  celebrated  grand  prize  founded  by  M. 
le  Due  de  Luynes. 

Since  1857,  M.  Lemercier,  an  artist  and  savaiit  oi 
great  merit,  has  utilised  M.  Poitevin's  processes  with  ex- 
cellent results  ;  and  Poitevin  himself  has  also  produced 
some  beautiful  collections,  among  which  we  may  men- 
tion an  album  of  forty-five  terracottas,  photographed  in 
the  galleries  of  the  Viscount  de  Janze,  a  photographic 


1 90  THE  APPLICATIONS  OF   PHOTOGRAPHY., 

reproduction  of  the  engraved  stones  of  the  Egyptian 
museum  of  the  Louvre  ;  and  in  the  galleries  containing 
the  most  remarkable  products  of  our  national  industry 
in  the  Museum  of  Art  and  Industry,  may  be  seen  a 
beautiful  photo-lithographic  stone. 

The  Processes  of  Baldiis,  Gamier  and  Salmon. 
In  measure  as  we  get  nearer  to  our  own  time  we  find 
progress  became  more  rapid.  In  1854  M.  Baldus  pro- 
duced proofs  of  photographic  engraving  which  justly  ex- 
cited public  admiration.  M.  Louis  Figuier  thus  de- 
scribes this  process  : — 

'  A  coating  of  bitumen  of  Judea  is  spread  on  a  cop- 
per plate.  On  the  plate  thus  prepared  with  the  impres- 
sionable resin  is  placed  a  photographic  proof  of  the 
object  to  be  engraved  on  transparent  paper.  This  proof 
is  a  positive,  and  must  in  consequence  produce,  by  the 
action  of  the  light,  a  negative  on  the  metal.  About  a 
quarter  of  an  hour's  exposure  suffices  to  imprint  the  ob- 
ject on  the  resin,  though  it  is  not  visible.  It  is  developed 
by  washing  the  plate  with  a  solvent  which  clears  away 
the  parts  unaffected  by  the  light,  and  leaves  a  negative 
picture  formed  by  the  parts  of  the  bitumen  rendered 
soluble  by  the  solar  rays. 

'  But  this  picture  is  formed  of  a  film  so  delicate  and  fine 
that  it  soon  begins  to  partly  disappear  from  the  effects  of 


HELIOGRAPH  Y.  191 


immersion  in  the  liquid.  To  give  it  the  necessary  soli- 
dity and  resisting  power,  it  is  left  for  two  days  to  the 
action  of  diffused  light.  After  the  picture  has  been  thus 
consolidated,  the  metal  plate  is  plunged  into  an  electro- 
typing  bath  of  sulphate  of  copper,  and  now  comes  the 
most  wonderful  part  of  this  process.  Attach  the  plate 
to  the  negative  pole  of  the  battery,  and  on  all  the  parts 
of  the  metal  unprotected  by  the  bitumen  a  coating 
of  copper  in  relief  will  be  deposited  ;  attach  it  to  the 
positive  pole,  and  the  parts  which  are  unprotected  will  be 
attacked  and  hollowed,  or,  technically  speaking,  bitten  out. 
Thus  can  one  obtain  at  will  from  the  negative  pole  an 
engraved  plate,  which  can  be  used  for  printing  from  like 
a  wood  engraving,  and  from  the  positive  pole  a  plate  as 
used  in  copper-plate  printing.'  ^ 

Since  this  time,  M.  Baldus  has  quite  dispensed  with 
electrotypy.  A  few  minutes  suffice  him  to  make  the 
plates  fit  for  the  copper-plate  engraving  process. 

It  is  by  means  of  a  chromic  salt  without  using 
the  bitumen  of  Judea,  that  M.  Baldus  sensitises  the 
copper  plate.  On  a  plate  thus  sensitised  is  placed  the 
glass  negative  or  positive  which  is  to  be  reproduced, 
and  the  whole  is   exposed  to  the   action  of  the  light. 

'   It  will  be  seen  that  this  process  is  very  similar  to  the  electrotypin'g 
method  of  Poitevin. 


192  THE   APPLICATIONS   OF   PHOTOGRAPHY. 

After  exposure  the  plate  is  placed  in  a  solution  of  per- 
chloride  of  iron,  which  attacks  it  in  all  the  parts 
where  the  salt  has  not  been  acted  upon  by  the  light  ;  a 
first  relief  is  thus  obtained. 

As  this  first  relief  is  not  sufficient,  it  is  augmented  by 
replacing  the  plate  in  the  perchloride  of  iron  solution, 
after  having  passed  over  it  a  printing-ink  roller.  The 
ink  attaches  itself  to  the  parts  of  the  plate  in  relief,  and 
protects  them  from  the  action  of  the  mordant.  By  re- 
peating this  treatment  the  lines  of  the  picture  may  be 
deepened  to  the  required  extent. 

If  a  photographic  negative  is  employed,  a  plate  is 
produced  for  use  as  in  the  copper-plate  process  ;  if  a 
positive,  then  the  lines  formed  are  in  relief,  and  the  plate 
can  be  used  for  typographic  printing. 

A  little  later  on,  in  1855,  a  new  and  extremely  in- 
genious process  was  brought  out  by  MM.  Garnier  and 
Salmon,  of  which  the  following  is  a  description  : — 

'  A  brass  plate  is  exposed,  in  the  dark,  to  vapours  of 
iodine,  then  submitted  to  the  action  of  light  behind  a 
negative,  and  rubbed  with  a  cotton  polisher  soaked  in 
mercury,  which  only  attacks  the  parts  unaltered  by  the 
light.  An  inking  roller  being  now  passed  over  this  plate 
the  ink  is  repelled  by  the  parts  where  the  mercury  has 
acted,  and  adheres  in  the  free  parts.     The  latter  there- 


HELIOGRAPH  Y.  1 93 


fore,  form  the  shadows,  and  when  treated  with  nitrate 
of  silver  give  a  plate  capable  of  use  as  in  copper- 
plate printing.  But  if  the  ink  is  not  removed,  and, 
after  the  first  corrosion  with  the  nitrate  of  silver,  a 
coat  of  galvanised  iron  deposited  on  the  plate,  the 
iron  adheres  only  to  the  parts  where  the  mercury- 
acted,  and  the  ink  being  now  removed  leaves  bare 
the  iodised  brass.  Mercury  is  again  applied  to  the 
plate,  and  does  not  adhere  to  the  iron.  Passed  under 
the  inking  roller  the  ink  only  adheres  to  the  iron.  If  a 
typographic  plate  is  required,  instead  of  iron,  gold  is 
used  to  form  the  deposit,  and  the  parts  unprotected  by 
the  latter  are  bitten  with  an  acid  to  the  required  depth.'  ^ 

By  an  analogous  process  M.  Garnier  obtained  helio- 
graphic  engravings  made  from  negatives  of  views  of 
monuments,  landscapes,  &c.,  of  very  remarkable  quality. 
This  operator  received  the  grand  prize  for  photography 
at  the  Exhibition. 

In  the  last  few  years  the  processes  which  we  have 
been  describing  have  undergone  many  most  important 
improvements.  We  shall  glance  at  the  methods  as 
actually  used  by  some  celebrated  operators. 

Albertype. — M.  Albert  is  a  photographer  of  Munich. 

•  Traite  general  de  Photographic,  par  Monckhoven,   sixi^me  edition. 
G.  Masson.   1875. 

O 


194  THE  APPLICATIONS  OF  PHOTOGRAPHY. 

well  known  from  his  remarkable  works  ;  his  name  has 
with  justice  been  given  to  some  photo-lithographic  pro- 
cesses based  on  Poitevin's  method.  Heliographic  en- 
gravings for  the  production  of  portrait-cartes  are  daily- 
made  in  M.  Albert's  studios  at  Munich,  and  200  engrav- 
ings can  be  easily  furnished  from  a  plate  in  12  hours. 

A  thick  glass  well  polished  is  covered  on  its  polished 
side  when  placed  in  a  horizontal  position  with  a  solution 
of  gelatine  and  bichromate  of  ammonium  and  albumen 
previously  heated.  This  first  slight  coating  is  exposed 
to  the  light  to  render  it  insoluble  in  water.  "When  this 
operation,  which  requires  great  delicacy  and  care,  is 
finished,  the  first  coating  of  gelatine  is  covered  with 
another  of  gelatine  isinglass,  bichromate  of  potash,  and  a 
mixture  of  resinous  matters  (benzoin,  tolu)  in  alcohol. 
When  dry,  the  plate  thus  prepared  is  placed  in  a  print- 
ing frame  under  the  negative  to  be  reproduced.  When 
the  exposure  has  been  sufficiently  long,  the  plate  is 
plunged  into  tepid  water,  which  dissolves  the  soluble  parts 
unaltered  by  the  light,  and  leaves  slightly  in  relief  the 
parts  where  the  light  has  acted.  This  operation  finished, 
the  plate,  when  dried  and  rubbed  with  an  oiled  flannel,  is 
ready  for  inking,  which  is  done  with  an  inking  roller  in 
the  lithographic  press ;  and  *  this,'  says  M.  Monckhoven, 
who  has  seen  the  clever  experimentalist  at  work,  '  is  the 


HFXIOGRAPHY.  1 95 


most  delicate  and  difficult  part  of  the  process,  and  re- 
quires a  clever  workman  to  do  it  well.  If  the  ink  is 
sticky  or  pasty  it  is  removed  with  turpentine  and  a  sponge. 
The  plate  must  be  placed  with  care  on  to  a  sheet  of 
india-rubber  or  a  coating  of  plaster,  with  papers  super- 
posed, &c.  The  greasy  ink  with  which  the  rollers  are 
coated  should  be  of  superior  quality.  Purple  is  often 
added  to  it  to  give  the  proof  the  same  appearance  as 
photographic  proof,  and  those  obtained  by  M.  Albert,  in 
point  of  exactitude,  delicacy,  and  tone,  leave  nothing  to 
be  desired.' 

Obernetter's  Process. — In  this  process,  which  gives 
very  good  results,  and  is  very  successful  in  Germany,  the 
gelatine  coating,  exposed  behind  a  negative,  is  covered 
with  an  impalpable,  metallic,  zinc  powder.  The  plate, 
after  this  operation,  is  heated  to  a  temperature  of  200° 
centigrade.  It  is  submitted  to  the  action  of  a  very 
weak  solution  of  hydrochloric  acid,  and  then  well  washed 
The  parts  of  the  gelatine  covered  with  the  metallic 
powder  can  be  more  or  less  damped  and  therefore  refuse 
the  greasy  ink,  whilst  those  free  from  the  zinc  receive  it. 

Modern  Heliography. — There  is  a  considerable  num- 
ber of  methods  of  photo-engraving.  At  Paris  some 
operators  have  arrived  at  very  satisfactory  results,  but 
the  greater  part  of  them  have  processes  based  on  secret 

o  2 


ig6  THE  APPLICATIONS  OF   PHOTOGRAPHY. 


operations,  and  minutiae,  analogous  to  Poitevin's  methods. 
To  show  what  may  be  done  by  these  processes  the  reader 
is  referred  to  the  opposite  engraving  which  has  been 
printed  With  the  text,  and  is  a  reproduction  of  a  sketch 
by  Gustave  Dore,  photographed  and  engraved  by  pro- 
cesses similar  to  those  which  are  here  described  in  this 
chapter. 

We  take  it  for  granted  the  reader  can  distinguish  the 
copper-plate  engraving,  which  is  formed  by  grooves  in 
the  metal,  from  the  typographic  plate,  in  which  the  lines 
forming  the  picture,  instead  of  being  sunk  in,  stand  out 
in  relief  from  the  metal.  Heliography  thus  furnishes, 
first,  plates  in  which  the  lines  forming  the  picture  are 
hollow  and  must  therefore  be  printed  as  by  the  copper- 
plate process,  and  cannot  be  used  for  printing  with 
type  ;  and  secondly,  the  plate  in  relief,  similar  to  a  wood- 
cut, and  very  easily  printed  with  type,  as  that  has  been 
done  for  our  fig.  38.  This  last  process  of  heliography 
is  especially  useful  for  illustrating  scientific  and  other 
books.  Photoglypty  (Woodbury  process),  which  we 
shall  describe  in  the  next  chapter,  admirable  though  it 
is,  as  yet  only  produces  plates,  which  must  be  printed 
without  text  in  a  special  press. 

Amongst  the  most  noted  French  operators  we  may 
mention  M.  Rousselon  and   Messrs.  Dujardin  Brothers. 


Fig.  36 


SPF.CIMEN    OF    A    HELIOGRAPHIC    ENGRAVING. 

(After  a  Drawing  by  Gustave  Dore. ) 


Ce  n'etait  qu'un  soldat  obscur  entre  dix  mille. 

guand  on  eut  la  victoire,  il  voulut,  le  premier, 
n  porter  la  nouvelle  a  sa  lointaine  ville. 
Et  partit,  fier  coureur,  agitant  un  laurier. 

Epuise  par  sa  course  effrayaate  et  sans  treve, 
II  mourut,  des  qu'il  fut  au  terme  du  chemin. 
Heureux  qui  pent  de  meme,  ayant  atteint  son  revt 
Mourir,  la  flamme  au  coeur  et  la  palme  a  la  main. 

A.  R. 


A  PAQUieifon. 


CQKTOTs. 

Fig.  37 

the  soldier  of  mauathon. 


[Page  197 


HELIOGRAPHY. 


197 


The  former  gentleman  manages  Messrs.  Goupil  and  Co.'s 
heliographic  establishment,  and  has  succeeded  not  only 
in  copying  old  engravings,  but  in  reproducing  Nature. 
Landscapes,  monuments,  and  even  portraits  are  now 
made  by  heliographic  processes.    Messrs.  Dujardin  apply 

Fig.  38. 


THE  SOLDIER   OF   MARATHON. 

(Heliographic  reduction  of  the  opposite  wood-engraving. 


themselves  principally  to  scientific,  engineering,  geogra- 
phical, and  cartographical  reproductions,  and  the  repro- 
duction of  old  manuscripts.  They  produce  by  heliography 
steel  plates,  which  have  great  merit,  both  from  the  num- 
ber  of  copies   they   will  furnish  and  the    cheapness  of 


I93  THE   APPLICATIONS   OF   PHOTOGRAPHY. 


their  production.  These  heliographic  processes  have 
already  found  numerous  applications,  nor  will  they  be 
wanting  in  the  future.  They  are  used  by  VEcole  des 
C//artes  for  the  reproduction  of  manuscripts,^  by  engineers 
and  architects  for  reducing  or  enlarging  their  designs, 
by  the  Bank  of  Belgium  and  the  Bank  of  France  for  the 
manufacture  of  notes. 

To  give  an  idea  of  the  utility  of  the  new  methods  for 
reducing  or  enlarging,  we  have  reproduced  on  the  preced- 
ing page  an  engraving  on  wood  representing  the  Soldier 
of  Marathon,  and  facing  it  is  a  reduction  of  it  which 
has  been  made  by  heliography.     (See  figs.  37  and  ^8.) 

'  The  photographic  reproduction  of  manuscripts  becomes  daily  of  more 
importance  ;  by  its  aid,  texts  which  have  become  almost  effaced,  and  which 
it  is  impossible  for  the  eye  to  read,  are  made  again  legible. 


199 


CHAPTER   II. 

PHOTOGLYPTY.      (THE   WOODBURY   PROCESS.) 

WOODBURY— IMPRESSION  OF  A  GELATINISED  PLATE  INTO  A  BLOCK  OF 
METAL  — WORKING  OF  PHOTOGLYPTIC  METHODS  IN  PARIS  — DE- 
SCRIPTION   OF    MESSRS.    GOUPIL'S    ESTABLISHMENT— M.    LEMERCIER. 

Thanks  to  the  improvements  of  the  English  scientist 
Woodbury,  the  wonderful  operations  which  we  have  just 
been  describing  have  been  greatly  perfected.  The  im- 
portance of  photoglypty,  an  art  born  but  yesterday  and 
hardly  known  to  the  public,  has  seemed  so  great  to  us 
that  we  have  thought  well  to  reserve  it  for  a  special 
description. 

What  principally  excites  admiration  in  this  new 
process  is  that  the  proofs  obtained  by  it  are  almost 
exactly  similar  to  those  produced  by  ordinary  photo- 
graphic processes  ;  they  have  the  same  colour,  the  same 
appearance,  and  the  same  fineness  of  quality.  Another 
almost  inestimable  advantage  which  this  process  offers 
is  that  the  proofs  maybe  multiplied  indefinitely  and  very 
rapidly. 


^200  THE  APPLICATIONS   OF   PHOTOGRAPHY. 

How  is  this  prodigy  performed  ?  This  is  what  we 
shall  try  and  teach  the  reader,  presuming  in  advance 
that  he  has  already  seen  these  photoglyptic  pic- 
tures at  the  printsellers'  and  booksellers',  and  perhaps 
bought  some  of  them,  thinking  that  he  was  getting 
ordinary  photographs.  We  were  for  a  long  time  under 
a  like  delusion.  Now  that  we  are  undeceived  we  think 
it  useful  and  interesting  to  undeceive  others,  by  thus 
describing  an  invention  which  is  assuredly  destined  to  a 
great  future. 

M.  Goupil,  the  publisher,  well  known  to  the  Parisian 
public,  has  acquired  the  right  to  work  the  Woodbury 
processes.  He  has  organised  a  fine  establishment  at 
Asnieres  under  the  intelligent  direction  of  M.  Rousselon, 
who  willingly  initiated  us  into  the  mysteries  of  the  new 
operations. 

We  shall  describe  faithfully  what  we  have  seen  and 
admired.  The  first  part  of  the  method  is  based  on  the 
properties  of  bichromatised  gelatine.  A  sheet  of  gelatine 
is  prepared  with  a  slight  admixture  of  Indian  ink,  or 
other  suitable  colouring  matter,  and  sensitised  with  an 
aqueous  solution  of  bichromate  of  potash.  This  leaf  of 
gelatine  is  placed  in  an  ordinary  printing  frame,  in  con- 
tact with  the  negative  exposed  to  light,  and  treated  as  in 
the  printing  and  developing  of  an  ordinary  carbon  proof. 


PHOTOGLYPTY.  20I 


The  latent  image  is  registered  in  the  gelatine  in  degrees 
of  solubility  or  insolubility,  just  as  in  the  carbon  print, 
the  degrees  corresponding  with  every  detail  of  the 
picture.  The  leaf  is  carefully  removed  from  the  printing 
frame  in  a  dark  room,  placed  on  a  glass  plate  covered 
with  india-rubber  varnish,  and  the  whole  is  then  placed 
for  twenty-four  hours  in  a  receptacle  containing  tepid 
water  constantly  renewed  in  order  to  dissolve  those  por- 
tions of  the  gelatine  which  were  protected  from  the 
action  of  the  light,  and  thus  render  the  leaf  very  much 
thinner.  On  being  removed  from  its  glass  support,  dried, 
and  held  up  to  the  light,  a  faithful  copy  of  the  negative 
picture  is  seen ;  the  lights  are  hollowed  out  and  the 
shadows  in  relief.  In  one  word,  the  photograph  is  repro- 
duced in  relief. 

It  will  be  seen  that  up  to  this  point  the  process  is 
very  similar  to  Poitevin's,  of  which  we  have  spoken  in 
the  previous  chapter.  But  the  miracle  now  commences. 
The  gelatine  leaf  is  next  placed  between  a  plate 
of  perfectly  level  steel  bound  with  iron,  and  a  sheet 
of  lead  mixed  with  antimony.  The  gelatine  film  with 
its  design  in  relief  and  engraving  thus  lies  between 
two  metal  surfaces,  the  one  of  steel  to  serve  as 
support,  the  other  of  lead  much  softer.  In  this  position 
it  is  submitted  to  great  hydraulic    pressure,   equal    to 


202 


THE  APPLICATIONS  OF   PHOTOGRAPHY. 


more  than  700,000  lbs.,  and  the  leaf  of  gelatine,  you  will 
say,  will  be  crushed  to  powder  beneath  such  pressure. 

Not  at  all ;  it  acts  like  the  die  when  striking  out  a 
coin  or  medal ;  although  friable  it  is  hard  and  unyielding, 

Fig.  39- 


PHOTOGLYPTIC   PRESS. 


harder  than  the  lead  into  which  it  penetrates.  In  fact, 
on  being  taken  from  the  press  the  lead  is  found  to  have 
received  the  exact  impression  of  the  gelatine  leaf,  and 
the  astonished  spectator  sees  every  detail  of  the  photo- 
graph reproduced  in  the  metal,  while  the  gelatine  relief 
leaves  the  press  quite  uninjured  and  may  be  used  again. 


PHOTOGLYPTY. 


203 


The  lead  plate  is  next  placed  in  a  special  press  (see 
fig.  39),  and  supplied  with  a  semi-transparent  ink  formed 
of  gelatine  and  Indian  ink  coloured  with  sepia ;  a  sheet 
of  paper  is  placed  over  this,  the  lever  is  pressed  down  ; 


Fig.  40. 


TURN-TABLE   REQUIRED    FOR    TAKING    PHOTOGLYPTIC    PROOFS. 


and  on  being  raised  a  few  moments  after,  to  anyone  who 
has  not  seen  the  details  of  this  astonishing  process,  the 
paper  seems  to  have  been  converted  into  an  ordinary- 
photograph.  The  press  once  set  going  10,000  facsimile 
prints  can  be  obtained  in  a  week. 


204  THE  APPLICATIONS   OF   PHOTOGRAPHY. 

The  photoglyptic  presses  are  placed  on  a  rotatory 
table  in  such  a  way  that  the  workman  can  keep  them 
constantly  supplied  with  the  thick  jelly-like  ink.  (Fig. 
40.)  The  ink  can  be  coloured  to  any  shade,  but  sepia  is 
the  most  generally  used,  as  it  gives  the  appearance  of 
the  photograph. 

It  is  possible  to  use  glass  instead  of  paper  for  printing 
on.  Photoglyptic  proofs  on  being  taken  from  the  press 
are  washed  in  an  alum  bath,  which  makes  the  print 
insoluble  and  so  fixes  it  ;  they  are  then  dried,  trimmed, 
and  mounted  on  cardboard,  and  are  now  ready  for  sale. 
It  is  hardly  necessar}^  to  say  that  in  this  description  we 
have  had  to  confine  ourselves  to  giving  our  readers  the 
principles  of  the  photoglyptic  process,  without  being  able 
to  enter  into  the  detail  of  the  delicate  manipulations 
which  require  great  skill  on  the  part  of  the  operator.  It 
will  be  patent  to  everyone  that  the  photographic  nega- 
tive  from  which  the  photoglyptic  proofs  are  to  be  formed 
must  be  made  under  the  best  conditions  of  sharpness 
and  clearness  ;  the  lights  and  shades  should  be  distinctly 
defined,  so  that  the  gelatine  film  receives  the  action  of 
the  light  freely. 

M.  Goupil  is  not  the  only  one  who  makes  use  of  this 
processs.    M.  Lemercier  has  also  organised  a  fine  pho- 


PHOTOGLYPTV.  205 


toglyptic  studio,  and  copies   have  been  printed  to  the 
extent  of  5,500  by  this  clever  artist.^ 

Photoglyphy  is  completely  successful  in  the  repro- 
duction of  portraits  from  nature,  but  it  is  especially 
suitable  for  reproducing  pictures,  engravings,  &c.,  which 
are  rendered  with  great  delicacy.  The  new  invention  has 
already  placed  an  innumerable  quantity  of  prints  in  the 

'  In  order  to  understand  the  principle  of  this  beautiful  process,  the 
reader  must  bear  in  mind  that  the  gelatine  relief  when  subjected  to  pressure 
is  first  laid  upon  a  perfectly  flat  and  true  plate  of  hard  steel,  the  leaden 
plate  is  then  placed  upon  the  relief,  and  the  whole  pressed  between  the 
parallel  jaws  of  the  hydraulic  engine.  The  direct  result  of  the  pressure  is 
that  the  soft  leaden  plate  has  taken  the  tnie  level  surface  of  the  steel,  and 
the  only  divergence  from  this  perfectly  level  surface  is  caused  by  the  gelatine 
relief,  which  has  impressed  into  the  lead  a  complete  intaglio  picture  in 
which  the  deepest  shadows  recede  farthest  from  the  level,  while  the  high 
lights  rise  to  the  true  level  of  the  plate.  The  success  of  the  process  depends 
entirely  upon  the  true  level  of  the  steel  plate  employed  in  the  press.  It 
will  therefore  be  readily  understood  that  in  pulling  the  impressions  the 
second  press  must  also  be  supplied  with  a  perfectly  level  plate  of  glass  or 
steel.  The  intaglio  slightly  greased  is  placed  in  position  and  charged  with 
a  warm  solution  of  semi-transparent  ink,  the  paper  placed  in  contact  with 
the  ink  ;  the  level  cover  of  the  press  is  then  brought  down  and  locked. 
The  superfluous  material  thus  pressed  out,  the  gelatinous  ink  sets  in  an 
instant,  and  the  resulting  proof  is  a  pictorial  relief  in  permanent  ink  ;  the 
high  lights  have  been  pressed  out,  leaving  the  white  paper  exposed,  and 
the  semi-transparent  ink  rises  in  beautiful  gradations  through  the  delicate 
shades  and  half-tones,  attaining  its  highest  relief,  and  therefore  its  greatest 
opacity,  in  the  deep  shadows.  But  when  the  proof  is  thoroughly  dry,  it 
presents  a  flat  surface  which  none  but  an  expert  could  distinguish  from  an 
ordinary  silver  print,  worked  by  the  Woodbury  Co.  of  London. 

The  Woodbury  process,  worked  by  the  Woodbury  Co.  of  London,  is 
largely  used  for  book  illustration  on  account  of  the  delicacy  and  beauty  of 
its  proofs.  It  has,  however,  one  great  defect  in  the  eyes  of  publishers,  and 
that  is,  that  the  proofs  require  to  be  cut  and  mounted. — Ed. 


206  THE  APPLICATIONS   OF   PHOTOGRAPHY. 


market,  amongst  which  we  may  mention  a  great  number 
of  reproductions  of  pictures  ;  some  of  the  latter  having 
been  produced  to  the  extent  of  30,000  copies  and  more. 
Photography,  years  ago,  would  have  been  powerless  to 
furnish  so  large  a  number.  Thus  these  photographic 
processes  will  henceforth  rank  among  the  industries.  A 
theatrical  journal  has  recently  made  use  of  photography 
for  reproducing  each  week  the  portraits  of  four  most 
noted  dramatic  artists.  The  prints  are  pulled  in  the 
Lemercier  presses  and  mounted  on  the  journal  itself  on 
a  space  reserved  for  each.^  This  curious  art  must  un- 
doubtedly prove  of  most  valuable  assistance  for  illus- 
trating books  of  fine  art,  travel,  &c.,  by  furnishing  proofs 
which  offer  all  the  advantages  of  photography  without 
its  drawbacks. 

It  is  hardly  necessary  to  insist  further  on  the  impor- 
tance of  the  new  invention  ;  it  will  be  plain  to  everyone 
that  it  must  be  considered  as  the  solution  of  a  great 
problem  destined  to  be  an  epoch  in  the  history  of  in- 
vention. The  only  objection  which  can  be  raised  to 
photoglypty  is  this :  Are  the  gelatine  prints  permanent  ? 
Will  they  be  as  little  affected  by  time  as  typographic 
prints  ?  It  is  probable,  for  it  is  not  easy  to  see  how 
gelatine  and  Indian  ink  can  alter ;  nevertheless,  time 
alone  can  solve  the  question  with  certainty. 

'  There  are  several  photo-illustrated  periodicals  in  London. — Ed. 


PHOTOGLYPTY.  207 


Another  but  less  important  objection  might  perhaps 
be  taken  to  the  somewhat  uncouth  name  of  the  new 
discovery  ;  but  this  name  is  very  appropriate  to  the  pro- 
cess, being  derived  from  two  Greek  words — photos,  Hght, 
and  gluptem,  to  engrave — to  the  union  of  which  one  will 
soon  get  accustomed. 


208  THE  APPLICATIONS   OF   PHOTOGRAPHY. 


CHAPTER  III. 

PHOTOSCULPTURE. 

AN    UNEXPECTED  DISCOVERY — PHOTOGRAPHY  APPLIED  TO  SCULPTURE — 
WILLfeME'S   PROCESS   IN    1861  — DESCRIPTION    OF   PHOTOSCULPTURE. 

We  have  just  seen  that  photography  has  furnished  the 
engraver  with  appliances  as  valuable  as  they  were  un- 
expected ;  but  the  art  created  by  Daguerre  can  do  yet 
more. 

Not  only  does  it  engrave  the  copper  plate  as  done 
by  the  hand  of  the  artist,  but  it  comes  to  the  aid  of 
the  sculptor,  and  relieves  him  in  his  work. 

In  the  course  of  the  year  1861,  the  Parisian  press 
announced  that  a  well-known  inventor  had  discovered 
the  means  of  reproducing  statues  by  photography,  not 
merely  to  represent  them  in  picture,  which  would  hav^e 
been  nothing  wonderful,  but  to  make  diminutive  fac- 
similes of  them.  If  an  object,  animate  or  inanimate, 
whether  marble  statue  or  living  man  or  woman,  were 
placed  in  the  midst  of  M.  Willeme's  (such  was  the  name 
of  the  ingenious  inventor)  studio,  a  few  days  after  a 


PHOTOSCULPTURE.  209 


little  statue  of  clay  would  be  modelled.  It  would  be 
done  by  photography,  and  the  statuary  image  would  be 
the  exact  representation  of  the  living  model. 

Such  a  result  appeared  incredible,  and  the  public, 
accustomed  to  being  hoaxed  by  the  press,  looked  on  it 
with  great  distrust.  But  facts  must  be  believed  ;  and  as 
soon  as  the  mystery  was  explained,  it  was  seen  that  there 
was  nothing  fantastic  or  incomprehensible  in  Willeme's 
process,  and  it  was  soon  proved  that  work,  perseverance, 
and  ingenuity  alone  composed  the  miracle. 

The  new  discovery  was  at  once  christened  with  the 
name  of  photosculptiire.  This  curious  art  is  designed, 
not  to  transform  a  photograph  on  paper  into  a  sculptural 
relief,  but  by  the  aid  of  photographs  to  imitate  in  a 
certain  way  a  statue  or  living  person. 

To  explain  the  processes  of  photosculpture,  we  quote 
a  passage  from  the  Aitnuaire  Scientifique  for  1861,  in 
which  Willeme's  invention  is  described:  *A  model  is 
placed  in  the  centre  of  a  circular  platform  the  circum- 
ference of  which  can  be  included  in  the  field  of  a  single 
camera,  by  which  several  photographs  of  the  objec 
from  different  points  of  view  are  to  be  obtained.  To 
simplify  matters,  suppose  these  photographs  be  restricted 
to  four — first,  A  of  the  face,  the  2nd  B  of  the  back,  the 

P 


210  THE   APPLICATIONS   OF   PHOTOGRAPHY. 

3rd  C  of  the  right  profile,  and  4th  D  of  the  left  profile 
— of  the  object ;  these  obtained,  it  is  necessary  to  use 
them  for  reproducing  the  model  in  relief.  To  effect  this 
the  plaster  or  clay  to  be  sculptured  is  placed  on  a  level 
plate,  the  circumference  of  which  is  divided  into  as  many 
equal  parts  as  there  are  photographs  to  be  taken,  in  this 
case,  therefore,  four.  Two  upright  tablets  are  fastened 
vertically  and  at  right  angles  to  each  other  to  the  plate 
on  which  the  plaster  is  placed.  These  tablets  are  made  to 
slide  to  or  from  the  plate,  and  are  for  the  purpose  of 
holding  two  of  the  photographs  which  must  be  those 
of  views  at  right  angles  to  each  other,  such  as  the 
front  A,  and  the  profile  C.  In  order  that  the  photo- 
graphs may  be  exactly  even,  both  they  and  the  tablets 
are  marked  with  a  double  system  of  horizontal  and 
vertical  lines,  which  greatly  facilitate  the  placing  in  true 
position. 

*  The  two  points  of  a  pantograph,  an  instrument  for 
counter-drawing,  are  applied  ;  the  one  to  the  photograph 
A,  of  which  it  follows  all  the  outline,  the  other  to  the 
soft  or  hard  mass  on  which  it  traces  a  silhouette,  an 
exact  copy  of  the  silhouette  of  the  photograph.  Another 
pantograph  at  right  angles  to  the  first  acts  in  a  similar 
manner  in  reproducing  the  silhouette  of  the  profile  C. 
In  the  same  way,  the  second  points  of  the  two  other 


PHOTOSCULPTURE.  211 


pantographs,  the  first  points  of  which  are  guided  in  the 
same  way  over  the  photographs  B  and  D,  reproduce  on 
the  block  the  silhouettes  of  the  back  and  of  the  profile 
D.  Simply  with  four  operations  the  mass  to  be  sculp- 
tured would  be  but  very  imperfectly  manipulated  ;  but 
nothing  prevents  that  instead  of  four,  eight,  twelve,  or 
twenty-four  views  should  be  taken  ....  in  fact,  the 
number  suflficient  for  obtaining  the  requisite  continuity 
of  the  exterior  outlines  so  that  there  would  be  but  an 
edge  or  two  to  correct  by  hand.  In  any  case  the  number 
of  the  pictures  must  be  one  divisible  by  four  ;  twenty- 
four  is  a  very  convenient  and  sufficient  number. 

'The  photographs  are  numbered  in  order  from  one 
to  twenty-four  ;  the  turning  plate  holding  the  clay  to  be 
modelled  is  also  divided  into  twenty-four  equal  parts. 
The  photographs  on  which  the  two  pantographs  act 
simultaneously  are  those  taken  at  an  angle  of  90  degrees 
from  each  other,  viz.,  one  and  seven,  two  and  eight,  three 
and  nine,  up  to  twenty-four  and  six,  and  each  time  the 
tablets  receive  fresh  photos,  the  plate  is  turned  one 
division. 

'  But  this  series  of  twenty-four  operations  will  only 
give  the  exterior  outlines,  and  the  statue  will  be  incom-> 
plete  until  such   indentations   as  the   nostrils,  ears,  &c. 


212  THE   APPLICATIONS   OF   PHOTOGRAPHY. 

have  been  brought  out.  These  M.  Will^me  obtains  by 
following  with  the  pantograph  not  only  the  profiles,  but 
also  the  lines  of  light  and  shade  which  represent  parts 
in  depression  and  relief.' 

In  1861,  M.  Willeme  constructed  a  photosculpture 
studio  at  the  top  of  the  Champs-Elysees.  He  has  suc- 
ceeded in  reproducing  some  statues,  and,  not  content 
with  this,  boldly  attempted  to  produce  the  statue  of  a 
living  person  just  as  his  portrait  is  taken  in  a  photo- 
graphic studio. 

For  some  time  past  Messrs.  Giroux  have  exhibited 
some  of  these  curious  productions  ;  amongst  others 
diminutive  figures  of  the  Duke  de  la  Rochefoucauld  and 
Madame  Galiffet  may  be  seen  ;  but  exact  as  are  the 
copies  of  these  personages,  from  an  art  point  of  view, 
they  present  nothing  more  than  common  and  mediocre 
statues.  How  can  a  gentleman  in  a  double-breasted 
coat,  or  a  lady  fortified  with  crinolines,  compete  with  the 
Apollo  Belvidere,  or  the  Venus  de  Medicis  ?  nudity  is 
imperiously  exacted  by  the  art  of  Praxiteles.  In 
spite  of  his  attempts  M.  Willeme  failed,  but  he  has  none 
the  less  created  a  new  application  of  photography  worthy 
in  all  respects  to  be  noted  and  taken  up  by  some  bold 
spirit 

Though,  from  an  art  point  of  view,  sculpture  after 


PHOTOSCULPTURE.  213 

nature  by  photography  seems  impossible,  there  is  reason 
to  hope  that  the  first  attempts  of  M.  Willeme  will  be 
one  day  perfected,  and  that  his  process  may  then  be  em- 
ployed in  reproducing,  with  precision  and  exactitude,  the 
works  of  old  and  modern  masters. 


214  THE  APPLICATIONS   OF    PHOTOGRAPHY. 


CHAPTER   IV. 

PHOTOGRAPHIC   ENAMELS. 

VITRIFICATION  OF  A  PHOTOGRAPH— CAMARSAC'S  PROCESS — ^JEWELLERY 
ENAMEL — METHOD  OF  MAKING — POITEVIN'S  METHOD— PERMANENT 
GLAZE  PHOTOGRAPHS. 

We  have  seen  that  the  image  of  the  camera  can  be  fixed 
on  paper,  on  metals,  and  on  glass. ^  It  can  also  be  so  burnt 
into  porcelain  by  a  certain  process  that  once  annealed  it  is 
as  indelible  as  ceramic  painting,  and  resists  time  and  all 
other  deteriorating  agents.  Many  manufacturers  have 
employed  photography  for  decorating  porcelain  vases  ; 
and  some  of  these  productions  are  really  works  of  art 
and  good  taste. 

M.  Lafon  de  Camarsac  was  the  first  who  conceived 
the  idea  of  employing  photography  in  this  curious  and 
unexpected  manner.  It  occurred  to  him  that  it  might 
be  possible  to   transfer   to  porcelain  a  positive   image 

'  Transferred  direct  to  the  surface  of  a  block,  it  dispenses  with  the 
Avork  of  the  artist  on  wood,  affording  the  engraver  an  exact  and  delicate 
guide  for  his  gi'aving  tool. 


PHOTOGRAPHIC   ENAMELS.  21  5 

formed  of  substances  vitrifiable  by  fire,  to  submit  this  to 
a  high  temperature,  and  thus  to  obtain  an  enamel  which 
reproduced  the  original  photographic  design.  With  this 
object  in  view  the  inventor  set  patiently  to  work,  and 
in  1854  photographic  enamels  were  invented. 

To  transform  the  heliograph  into  an  indelible  painting, 
Camarsac  made  a  sensitive  coating  capable  of  receiving 
the  impression  from  a  glass  photograph  without  adhering 
to  the  latter.  After  exposure  to  light  the  picture  is 
formed  clear  and  distinct.  The  inventor  now  substituted 
ceramic  colours  for  the  parts  which.^  should  be  destroyed 
by  the  action  of  heat. 

By  means  of  a  fine  sieve  the  inventor  deposited  the 
metallic  oxide  colours  delicately  on  the  surface  of  the 
coating ;  he  spread  these  powders  either  with  a  brush  or 
by  imparting  a  rapid  movement  to  the  plate.  In  pro- 
portion as  the  powder  is  spread  over  the  coating,  the  heat 
should  be  gradually  increased.  The  enamel  powders 
follow  most  delicately  all  the  features  of  the  drawing, 
which  they  partly  penetrate,  and  the  vigour  and  delicacy 
of  which  they  faithfully  render.  After  cooling,  the  proof 
must  be  dusted  to  remove  any  particles  of  colour  which 
may  adhere  to  the  whites  of  the  picture. 

The  piece  is  now  ready  for  the  buniing-in  process 
which  is  done  in  the  same  way  as  usual  in  ceramic-paste 


2l6  THE   APPLICATIONS   OF   PHOTOGRAPHY. 

colouring,    a    more    or    less    hot   fire    being    employed 
according  to  the  nature  of  the  colours  to  be  produced. 

The  fire  destroys  the  organic  substances,  and  fixes 
the  picture  formed  by  the  indestructible  colours  as  soon 
as  they  are  vitrified. 

'  One  of  the  remarkable  properties  of  these  pictures,' 
says  Camarsac,  *  is  the  appearance  of  fine  enamel  which 
they  present,  and  which  no  other  painting  could 
furnish  with  a  like  degree  of  delicacy.  This  cir- 
cumstance proves  fully  that  the  powder  enamel  has 
taken  exactly  the  pl^ace  of  the  organic  matter,  and  it 
must  be  seen  that  this  appearance  is  due  to  the  remark- 
able delicacy  of  the  photographic  deposit,  which  is  formed 
in  degradations  of  thickness  inappreciable  to  the  eye 
....  There  is  no  colour  which  cannot  be  applied  to  the 
heliographic  surface  ;  gold  and  silver  are  as  easily  used 
as  blue  or  purple.'  ^ 

It  will  be  seen  that  the  inventor  of  photographic 
enamels  describes  his  process  with  great  reserve,  wishing 
doubtless  t<9  keep  it  secret.  But  we  are  now  acquainted 
with  Poitevin's  method,  the  details  of  which  we  will 
briefly  describe. 

To  produce  a  portrait  on  enamel  for  mounting,  as 
they  are  often  done,  in  a  brooch  (fig.  41),  a  pin,  &c.,  a 

*  Lafon  de  Camarsac's  Patents,  1874. 


PHOTOGRAPHIC  ENAMELS. 


217 


Fig.  41. 


positive  on  glass  is  first  made  of  the  object  to  be  repre- 
sented. 

This  positive  is  applied  to  a  glass  coated  with  a 
sensitised  surface  formed  of  a  mixture  of  gum  and 
bichromate  of  potash.  The  light  traverses  the  trans- 
parent parts  of  the  positive,  and  acts  on  the  bichromate 
of  potash  in  a  manner  which,  though  invisible  to  the 
naked  eye,  modifies  it  in  such  a  way  as  to  give  only  to 
those  parts  the  curious  property  of  retaining  the  charcoal 
dust  or  powder.  As  soon 
as  the  exposure  to  the  light 
is  finished,  the  bichroma- 
tised  plate  is  removed,  and, 
though  appearing  totally 
unaltered  to  the  eye,  if  a 
fine  charcoal  dust  issprinkled 
over  it  by  means  of  a  sieve 
(fig.  42),  the  charcoal  only  ad- 
heres to  the  parts  where  the 
light  has  acted  and  nowhere 
else.    Thus  this  fine  charcoal 

shower  brings  to  view,  as  if  by  enchantment,  a  portrait 
both  delicate  and  faithful,  in  which  the  distinctions  of 
light  and  shade  are  well  preserved. 

The  photographic  proof  is  thus  developed,  a  coating 


PHOTO-ENAMEL     BROOCH. 


2l8 


THE   APPLICATIONS   OF   PHOTOGRAPHY. 


of  charcoal  showing  the  design  ;  but  this  coating  is  not 
permanent.  By  means  of  a  brush  a  coat  of  collodion 
{fiormal)  is  spread  over  it,  which  soon  dries. 

The  next  operation  is  one  requiring  very  great  dex- 
terity of  hand.     The  fine  coating  of  collodion  has  to  be 


Fig.  42. 


DUSTING    SIEVE. 


separated  by  the  aid  of  pointed  instruments  from  the 
glass  plate,  and  brings  away  with  nt  the  charcoal  proof. 
The  film  of  collodion  is  then  placed  on  the  convex  plate 
formed  of  white  enamelled  copper  ;  a  fixing  paste  similar 
to  that  used  by  ceramic  painters  is  spread  over  the  enamel 
with  a  brush,  and  the  fixing  agent  becomes  incorporated 


PHOTOGRAPHIC   ENAMELS.  219 


with  the  carbonised  parts  of  the  proof,  of  which  it  retains 
the  image  or  design. 

When  subjected  to  a  red  heat  in  an  enameUing  fur- 
nace the  fixing  paste  adheres  to  the  charcoal  powder, 
vitrification  takes  place,  and  all  the  organic  matters  are 
destroyed  ;  and  the  vitrified  carbon  alone  is  fixed  in  an 
indelible  manner. 

If  a  coloured  proof  is  required,  the  design  in  black  is 
traced  over  by  an  artist  with  colouring  pastes  used  for 
decorating  ceramics,  not  always,  of  course,  without  some 
slight  damage  to  the  beauty  of  outline  and  tone  of  the 
photograph. 

Messrs.  Desroche,  Henderson,  Lochard,  Gongenheim, 
Forest,  Berthand,and  others,  are  justly  celebrated  for  their 
photographic  enamels,  which  are  much  used  in  jewellery, 
and  we  have  seen  portraits  made  by  this  last  artist  which 
have  the  quality  of  ancient  miniatures,  with  the  lifelike 
resemblance  which  photography  alone  can  assure. 

Similar  processes  have  been  used  by  some  operators 
to  obtain  the  vitreous  or  glazed  photographs  of  which 
some  remarkable  specimens  were  exhibited  at  the  Exhibi- 
tion of  1867. 


220  THE   APPLICATIONS   OF   PHOTOGRAPHY. 


CHAPTER   V. 

PHOTOMICROGRAPHY. 

THE  TOY  MICROSCOPES  OF  THE  PARIS  INTERNATIONAL  EXHIBI- 
TIONS—450  DEPUTIES  IN  THE  SPACE  OF  A  PIN'S  HEAD— ARRANGE- 
MENTS OF  PHOTOMICROGRAPHIC  APPARATUS  —  THE  NATURAL 
SCIENCES  AND  PHOTOMICROGRAPHY — RESOURCES  BORROWED  FROM 
THE    HELIOGRAPH. 

The  reader  who  may  have  visited  the  International 
Exhibitions  in  Paris  in  the  years  1859  ^^^  ^^^7  cannot 
have  forgotten  the  wonderful  productions  of  microscopic 

photography    which    appeared 
^1 ''-  there.     At   the   Palace  of    In- 

dustry thousands  of  objects 
were  sold,  giving  some  idea 
of  the  minuteness  to  which  pho- 

TOY   MICROSCOPE   OF   THE   EXHI- 

BiTioN  OK  X867.  tographic  prints  could  attain. 

There  were  small  microscopes  (fig.  43)  containing 
photographs  the  surface  of  which  did  not  exceed  the  size 
of  the  head  of  a  pin,  where  were  to  be  seen  through  a  magni- 
fying glass  the  portraits  of  the  450  deputies  of  the  Empire. 


PHOTOMICROGRAPHY.  221 

Photography  succeeds  in  taking  the  impression  of  a 
diminished  image,  but  it  is  also  capable  of  rendering 
permanent  the  images  magnified  by  the  microscope. 
Before  studying  Lilliputian  photographs  we  shall  pass  in 
review  those  which  able  operators  now  obtain  from 
images  enlarged  by  the  microscope.  We  shall  examine 
the  results  of  the  process  called  photomicrography. 

Photomicrography  has  rendered  and  still  renders 
every  day  the  greatest  services  to  the  Natural  Sciences. 
Microscopic  study  is  fatiguing,  and  the  eye  cannot  observe 
for  long  an  object  through  the  magnifying  glasses  of  this 
instrument  without  feeling  wearied.  Thanks  to  photo- 
micrography, the  naturalist  can  have  in  his  hands  prints 
representing  under  a  considerable  enlargement  the  infu- 
soria, grains  of  pollen,  and  the  most  delicate  organs  of 
vegetables  or  animals.  On  this  account  this  art,  the 
birth  of  yesterday,  must  already  be  considered  as  a 
valuable  assistant  to  scientific  investigation. 

We  shall  chiefly  examine  microscopic  photography  in 
relation  to  its  application  to  the  natural  sciences.  We 
shall  do  so  by  the  aid  of  a  distinguished  amateur,  as 
skilful  a  photographer  as  he  is  a  good  microscopist,  M. 
Jules  Girard,  who  has  kindly  authorised  us  to  make  ex- 
tracts from  his  interesting  works. 

The  arrangement  of  a  photomicrographic   apparatus 


222  THE   APPLICATIONS   OF   PHOTOGRAPHY. 

requires  peculiar  care.  *  However  well  arranged  a  camera 
may  be/  says  M.  Girard,  'it  is  indispensable  that  it  should 
satisfy  numerous  conditions  in  ordinary  photography, 
which  it  is  more  rational  to  avoid  in  photomicrography 
by  simplifying  and  reducing  the  number  of  its  parts. 
In  adapting  a  microscope  to  the  end  of  a  camera  such 
as  every  photographer  possesses,  there  is  no  need  of  any 
particular  arrangement,  because  any  one  of  these  instru- 
ments, of  whatever  kind  it  may  be,  is  suitable  for  the  pro- 
duction of  a  picture.  Let  it  be  a  bellows  camera  which 
will  draw  out  to  about  a  yard,  and  of  such  dimensions 
as  will  take  in  a  glass  plate  of  8  x  lO  inches  ;  this  size 
will  be  more  than  sufficient.  The  shape  of  the  glass  plates 
usually  sold,  which  are  longer  than  they  are  broad,  is  not 
very  suitable  to  receive  an  image  which,  being  circular, 
is  always  inscribed  in  a  square,  when  the  whole  field  of 
projection  is  made  use  of:  the  circle  is  also  more  charac- 
teristic of  microscopic  impressions.' 

In  order  not  to  change  anything  in  the  arrangement 
of  the  camera  there  must  be  a  plate-holder  or  series  of 
plate-holders,  which  fit  one  within  the  other,  and  also 
fitting  the  slide  which  is  used  in  ordinary  photography. 
The  glass  plates  must  also  be  specially  cut  in  squares  of 
two  or  three  sizes.  The  sensitive  surface  is  thus  more 
cleanly  and   regularly  covered,  and   there  will  be   also 


PHOTOMICROGRAPHY.  223 

more  economy  in  the  use  of  the  chemicals.  With  certain 
glass  plates,  such  as  those  used  for  the  stereoscope,  it 
would  be  advantageous  to  employ  a  double  slide  giving 
two  impressions  at  the  same  time. 

The  front  of  the  camera  is  usually  made  moveable, 
so  that  lenses  of  various  sizes  can  be  used. 

The  ordinary  lens-holder  being  removed  from  the 
front  of  the  camera,  there  should  be  fixed  over  the  aper- 
ture, in  such  a  manner  as  to  prevent  any  light  being  ad- 
mitted at  the  junction,  a  truncated  cone  of  india-rubber, 
strong  black  cloth,  or  other  perfectly  opaque  flexible 
material,  the  tube  of  the  microscope  being  irtserted  into 
the  narrow  end  of  the  cone. 

It  is  absolutely  necessary  that  the  junction  should 
be  made  by  a  simple  contrivance  in  order  to  give  flexi- 
bility to  every  movement.  A  mere  opening  in  the 
flange  allowing  the  tube  of  the  microscope  to  be  in- 
serted into  the  camera  would  make  the  combination  too 
rigid,  for  the  two  instruments  must  be  so  united  as  to 
preserve  to  each  a  perfectly  independent  motion  (fig. 
44),  so  that  that  of  the  one  may  not  interfere  with  that 
of  the  other.  The  microscope  is  thus  withdrawn  from 
the  inevitable  shakes  given  to  the  camera ;  in  regulating 
the  focus,  or  in  withdrawing,  even  with  all  possible  pre- 
caution, the   dark  slide  containing  the  sensitised  glass 


224  THE   APPLICATIONS   OF   PHOTOGRAPHY. 

plate,  the  slightest  shake  would  cause  a  disturbance  of 
the  position  of  the  image.^ 

As  an  ordinary  camera  cannot  generally  be  sufficiently 


Fig.  44 


MICROSCOPE   FITTED   TO   THE  CAMERA. 


drawn  out,  there  may  be  fixed  to  the  flange  a  metallic  or 
wooden  cone,  to  the  other  end  of  which  is  fastened  the 
india-rubber  or  black  cloth  junction. 

^  This  independent  action  of  the  camera  and  microscope  containing 
the  object-glass,  confers  a  decided  advantage  in  the  hands  of  a  skilled 
operator.  But  the  amateur  would  probably  be  safer  in  using  the  microscope, 
cone,  and  camera  rigidly  united,  as  it  is  of  great  importance  to  obtain  a  direct 
light  thrown  from  the  mirror  of  the  microscope  through  the  axis  of  the 
instruments ;  and,  moreover,  the  stage  of  the  microscope  which  carries 
the  object  to  be  photographed  and  the  prepared  plate  ought  to  be  perfectly 
parallel  to  each  other. — Ed. 


PHOTOMICROGRAPHY.  225 

In  place  of  the  ordinary  camera  a  simple  oblong 
box  provided  with  a  slide  may  be  used,  but  then  the 
focal  distance  would  be  invariably  the  same.  Though 
an  ordinary  microscope  may  be  used,  it  will  be  found 
better  to  have  the  tube  made  as  short  as  the  mechanism 
will  admit  of,  as  a  tube  of  the  usual  length  would  pre- 
vent the  expansion  of  the  pencil  of  light  thrown  upon  the 
sensitive  plate.  The  interior  should  be  coated  with  a  dull 
black,  or  still  better  with  very  fine  black  velvet,  in  order 
to  avoid  any  reflections  from  a  polished  surface. 

The  microscope  should  be  attached  to  a  heavy  metal 
stand  so  as  to  make  it  as  steady  as  possible.  The  height 
of  the  support  should  be  such  that  the  optical  axis  of 
the  microscope  is  exactly  in  a  line  with  the  centre  of  the 
ground-glass  back  of  the  camera.  The  apparatus  could 
then  be  put  on  an  ordinary  table  very  firmly  placed  ;  but 
the  height  of  ordinary  tables  is  not  adapted  to  the  con- 
venience of  the  operator,  and  want  of  sufficient  height  is 
a  cause  of  constraint  and  fatigue.  The  best  manner,  in 
our  opinion,  to  place  it  in  a  position  suitable  to  work  at 
one's  ease  is  to  let  it  rest  on  a  bench,  of  the  breadth  of 
the  camera  and  about  a  yard  and  a  half  long,  mounted 
on  solid  legs  having  an  outward  inclination  to  give  it 
more  firmness  (fig.  45).     In  order  to  compensate  for  the 

Q 


226  THE  APPLICATIONS  OF   PHOTOGRAPHY. 

inequalities  which  are  often  found  in  flooring,  it  would  be 
well  to  furnish  it  with  levelling  screws. 

Near  the  bottom  of  the  legs  another  board  might  be 
fixed,  which  would  increase  their  firmness  and  also  be 
very  convenient  for  placing  any  small  articles  upon 
while  working,  should  there  be  no  other  table  at  hand. 
The  height  would  be  regulated,  so  that  when  standing, 
the  centre  of  the  ground  glass  would  be  on  a  level  with 

Fig.  45- 


ARRANGEMENT   OF   THE   PHOTOMICROGRAPHIC  APPARATUS   ON   A   BENCH. 

the  eyes.  To  stand  upright  is  perhaps  a  little  more 
fatiguing  than  to  make  the  trials  of  focussing  seated  on 
the  edge  of  a  lower  table,  but,  by  standing,  one  gains 
considerably  in  ease  and  quickness  of  movement*     In 

'  The  bench  ought  to  be  made  iong  enough  to  support  the  camera  when 
fully  expanded. — Ed. 


PHOTOMICROGRAPHY.  22/ 

case  the  camera,  when  expanded,  should  be  much  longer 
than  the  bench  which  supports  it,  it  would  be  necessary 
to  add  metal  brackets,  or  in  some  other  way  support  the 
extreme  end  of  the  camera  to  prevent  any  rocking  mo- 
tion when  the  movable  back  is  inserted  or  taken  out. 

As  this  apparatus  does  not  admit  of  the  focussing 
of  the  image  so  readily  as  in  the  ordinary  photographic 
camera,  a  bench  like  the  one  described — which  may  be 
readily  moved  to  suit  the  light—  will  prove  of  great  service. 
By  not  having  the  camera  too  much  expanded  the  awk- 
wardness of  stretching  the  arm  to  reach  the  focussing 
screw,  when  the  head  is  under  the  focussing  cloth,  is 
avoided.  In  case  of  need  recourse  might  be  had  to  an 
assistant  who  would  turn  the  screw  according  to  direc- 
tions given.  Wishing  to  avoid  this  inconvenience,  M.  de 
Brebisson  has  made  use  of  a  mirror  placed  at  the  bottom 
of  the  camera.  The  operator  then  leans  over  the  appa- 
ratus placed  upon  a  table  of  suitable  height,  the  head 
under  the  focussing  cloth,  and  the  hand  free  to  hold  the 
screw.  A  system  of  screws  and  connecting  rods  has  also 
been  devised  ;  but  a  position  even  a  little  inconvenient 
to  which  one  soon  gets  accustomed  is  preferable  to 
having  recourse  to  pieces  of  mechanism  which  act  at  a 
distance,  and  for  that  reason  are  often  defective.  The  sen- 
sitiveness of  a  micrographic  screw  does  not  suit  such  ar- 

Q2 


228 


THE   APPLICATIONS   OF   PHOTOGRAPHY. 


rangements  well,  for,  however  correct  their  action  may  be, 
it  can  never  equal  the  free  and  direct  motion  of  the  hand. 
The  microscope  may  also  be  placed  vertically,  as  re- 
presented by  fig.  46. 


VERTICAL    MICROSCOPE   ADAPTED    TO    THE   CAMERA    FOR    PHOTOMICROGRAVHY. 

V  is  the  focussing  screw.  O  represents  the  slide 
which  carries  the  object  to  be  magnified,  placed  above 
the  object-glass  A.  But  the  arrangement  we  have  pre- 
viously described  is  to  be  preferred. 


PHOTOMICROGRAPHY. 


229 


The  photomicrographic  apparatus  being  properly 
placed,  it  is  necessary  to  give  every  possible  attention  to 
lighting  the  object  effectually.  This  is  of  very  great  im- 
portance in  such  operations.  Under  certain  conditions 
the  light  of  the  sun  may  be  replaced  by  an  artificial 
light  produced  by  the  combustion  of  magnesium  or  the 
electro-magnetic  light,  or  oxy-hydrogen  light  as  in  fig.  47. 

Fig.   47- 


PHOTOMICROGRAPHIC   APPARATUS   FOR   ARTIFICIAL    LIGHT. 

We  shall  not  enter  into  matters  of  practical  detail 
analogous  to  those  we  have  described  in  the  Second  Part 
of  this  work  ;  we  shall  confine  ourselves  to  speaking  of 
the  results  due  to  this  branch  of  the  photographic  art. 
The  tissues  of  plants,  insects,  the  marvels  of  the  invisible 
world,  which  fatigue  the  eye  when  examining  them 
through  the  microscope,  are  fixed  on  the  collodion  with  a 
precision  unknown  to  the  most  scrupulous  draughtsman. 


230 


THE  APPLICATIONS  OF   PHOTOGRAPHY. 


Fig.  48  gives  the  portrait  of  a  flea  photographed  after 
being  enlarged  by  a  miscroscopic  object-glass.  The  en- 
graving has  been  done  in  such  a  manner  as  to  reproduce 
faithfully  the  photograph,  which  was  taken  by  the  pro- 
cesses described  in  this  chapter. 


Fig.  49. 


Fig.  50. 


FACSIMILE   OF   THE   PHOTOGRArH    OF   SECTIONS 
OF   THE   STEM    OF   A   CANE. 


SECTION   OF   THE  WOOD   OF   A 


Fig.  49  is  the  reproduction  of  a  photograph  of  thin 
sections  of  a  cane.  At  a  is  seen  the  transverse  section 
o(  the  stem,  and  at  b  the  longitudinal  section.  Beside 
it  we  place  the  section  of  a  piece  of  fir  represented  in  the 
same  manner  (fig.  50). 

By  uniting  the  processes  of  heliography  and  photo- 
micrography, the  photograph  obtained  directly  from  the 


PHOTOMICROGRAPHY. 


231 


magnified  object  has  been  converted  into  a  heliographic 
plate. 

Fig.   51  is  printed  from  a  heliographic  plate  which 


Fig-  51 


CROUP    OF    DIATOMS. 


was  taken  from  a  photograph  of  diatomaceae  representing 
these  infinitely  small  objects  magnified  450  diameters. 
This  engraving  is  the  mathematically  exact  copy  of  the 


232 


THE  APPLICATIONS   OF   PHOTOGRAPHY. 


image  given  by  the  microscope.  These  astonishing 
organisms,  which  are  met  with  in  incalculable  numbers 
on  the  surface  of  sea-weeds  or  pebbles  which  have  been 
exposed  to  the  action  of  mineral  water,  and  which  in 

Fig.  52. 


SECTION   OF    THE    FIN    OF   A   WHALE. 

reality  are  smaller  than  the  smallest  prick  given  by  the 
finest  needle,  are  here  figured  by  the  heliograph  just  as 
Nature  has  created  them. 

Photography  has  fixed  their  images  magnified  by  the 
microscope  on  collodion  ;  it  has  then  formed  the  en- 


PHOTOMICROGRAPHY.  233 

graved  plate,  and  enabled  us  to  insert  it  in  this  book. 
This  plate  was  produced  by  heliography  from  a  very  fine 
photomicroscopic  negative  by  M.  Jules  Girard.  The 
other  two  designs  (figs.  52  and  53)  were  produced  in  the 
same  manner. 

Fig.  53- 


El'IDERMIS   OF    A    CATKRPILLAR. 


The  first  (fig.  52)  represents  the  section  of  the  fin  of  a 
whale. 

And  the  second  (fig.  53)  the  epidermis  of  a  cater- 
pillar. 

We  think  these  examples  are  sufficient  to  prove  the 


234  THE  APPLICATIONS  OF  PHOTOGRAPHY. 

immense  resources  which  the  Natural  Sciences  may  find 
in  the  processes  of  photomicrography.  But  if  the  operator 
is  now  able  to  fix  the  image  of  an  almost  imperceptible 
object  magnified  by  the  microscope,  he  can  also,  as  we 
shall  see,  perform  the  inverse  operation  ;  that  is  to  say, 
he  can  photograph  the  image  of  an  object  reduced  to 
Lilliputian  dimensions.  The  toy  microscopes,  which  we 
have  already  mentioned,  afforded  a  trifling  specimen  of 
this  last  application  of  an  art  which  subsequently  pro- 
duced the  photographic  despatches  of  the  siege  of  Paris. 


235 


CHAPTER  VI. 

MICROSCOPIC   DESPATCHES  DURING  THE  SIEGE   OF 
PARIS. 

APPLICATION  OF  MICROSCOPIC  PHOTOGRAPHY  TO  THE  ART  OF  WAR — 
THREE  MILLION  PRINTED  LETTERS  OF  THE  ALPHABET  ON  THE  TAIL 
OF  A  PIGEON — ENLARGEMENT  OF  THE  DESPATCHES — THEIR  CON- 
VEYANCE   BY   CARRIER-PIGEONS. 

During  the  war  of  1870-71,  when  Paris  was  invested 
by  the  enemy,  photography  succeeded  in  reducing  the 
size  of  the  messages  sent  by  carrier-pigeons,  so  as  to 
render  them  almost  invisible  to  the  naked  eye.  No 
philosopher  could  have  imagined  this  use  of  photography, 
called  forth  by  the  dire  necessities  of  war. 

No  one  can  have  forgotten  the  service  rendered  by 
balloons  during  the  siege  of  Paris,  nor  the  wonderful  part 
played  by  carrier-pigeons,  which  brought  to  the  besieged 
city  news  from  the  outer  world.  But  these  birds,  how- 
ever strong  they  might  be,  could  only  carry  with  them 
very  light  burdens  through  the  air.  A  thin  sheet  of 
paper  two  or  three  inches  square  was  all  the  load  that 
could  be  entrusted  to  these  winged  messengers.     But 


2^6  THE  APPLICATIONS  OF   PHOTOGRAPHY. 

how  write  orders,  send  despatches,  give  precise  instruc- 
tions in  such  a  minute  letter  ?  the  most  able  caligrapher 
could  hardly  make  it  contain  the  letters  in  a  single 
page  of  a  printed  volume. 

Microscopic  photography  came  to  the  assistance  of 

Fig-  54- 


CARRIER-PIGEON    WITH    PHOTOGRAPHIC    DESPATCHES. 

the  besieged  ;  it  solved  the  difficulty  as  no  other  art  could 
have  done  ;  it  reproduced  on  a  film  of  collodion  weighing 
less  than  a  grain,  more  than  three  thousand  despatches, 
that  is  to  say,  the  amount  of  sixteen  pages  of  folio 
printed  matter. 

We  shall  recall  briefly  these    memorials  of   micro- 
scopic photography  utilised  by  the  aid  of  carrier-pigeons. 


MICROSCOPIC  DESPATCHES.  237 

At  Tours,  all  public  or  private  despatches  were 
printed  on  a  large  sheet  of  paper,  which  could  contain 
about  300,000  letters.  M.  Dagron,  who  left  Paris  in  a 
balloon,  reduced  this  big  poster  to  a  small  negative 
scarcely  one  quarter  the  size  of  a  playing  card. 

These  were  at  first  printed  on  a  thin  sheet  of  paper. 


Fig.  55- 


QflLL   CONTAINING    MICROSCOPIC    DESPATCHES    FASTENED    TO   A    TAlL- 
FEATHER    OF    CARRIER-PIGEON. 

but  afterwards  on  a  film  of  collodion,  which,  though 
weighing  less  than  one  grain,  contained  the  matter  of 
several  newspapers. 

Several  of  these  films  representing  a  considerable 
number  of  despatches  were  rolled  up  and  enclosed  in  a 
quill  about  the  size  of  a  tooth-pick.  This  light  and 
novel  letter-box  was  attached  to  the  tail  of  the  pigeon  as 
represented  in  figs.  54  and  55.  The  bird-messenger  only 
carried  this  light  burden.  Care  was  taken  on  his  arrival 
and  at  his  departure  to  put  a  stamp  on  his  wing  to  prove 


238  THE  APPLICATIONS   OF   PHOTOGRAPPIY. 

the   date   of  the   receipt,  or  despatch  of  the  messages 
(fig.  56). 

A  very  considerable  number  of  printed  pages  were 
reproduced  by  the  processes  of  M.  Dagron  and  his 
assistant,  M.  Fernique.  Each  page  contained  about  5,000 
letters,  say  about  300  despatches.    Sixteen  of  these  pages 

Fig,  56. 


STAMPS,   SHOWING  WHEN   DESPATCHES   WERE  FORWARDED  OR   RECEIVED,   PRINTED 
ON    THE   WING.  * 

were  contained  on  a  film  about  two  inches  long  and  one 
inch  broad,  and  weighing  less  than  one  grain.  We  have 
endeavoured  to  give  the  exact  appearance  of  one  of  these 
despatches  in  our  figure  57.  The  reduction  was  made  to 
the  eight-hundredth  part  of  the  size  of  the  original.  Each 
pigeon  could  carry  twenty  of  these  films  in  a  quill,  the 
whole  not  weighing  more  than  fifteen  grains.  These  de- 
spatches united  could  easily  form  a  total  of  two  to  three 


MICROSCOPIC  DESPATCHES. 


239 


Fig.  57- 


627- 


"6V2 


millions  of  letters — that  is   to  say,  the  matter  of  ten 
such  volumes  as  this. 

To  produce  these  very  minute  specimens  of  photo- 
graphy, recourse  was  had  to  the  process  already  utilised 
before  the  war  in  the  construc- 
tion of  the  little  photographic 
toy  microscopes,  and  of  which 
the  following  is  a  description.. 
The  albumen  process  was  used, 
which  gives  the  greatest  pos- 
sible delicacy  to  the  negative 
image.  This  small  image, 
further  reduced  by  the  aid  of 
lenses,  is  reproduced  in  the  focus 
cf  a  camera,  and  fixed  on  a 
plate  of  collodionised  glass,  on 
which  several  microscopic  photo- 
graphs are  received  at  the  same 
time.  This  plate  will  be  a  positive  ;  the  plate  from 
which  it  was  produced  being  a  negative.  It  is  then 
cut  into  small  fragments  each  containing  a  picture. 
M.  Dagron  fixed  his  little  microscopic  photographs  in 
1867  into  various  articles,  such  as  the  toy  microscopes 
already  spoken  of,  into  rings,  penholders,  &c. 


FACSIMILK  OF  A  MICROSCOPIC 
DESPATCH  DURING  THE  SIEGE 
OF  PARI*. 


One  of  the  practical  difficulties  at  this  time  was  the 


240  THE   APPLICATIONS   OF   PHOTOGRAPHY. 

magnifying  the  little  glass  plates  sufficiently.  M.  Dagron 
succeeded  in  doing  so  by  employing  the  Stanhope 
lens.^ 

It  is  a  miniature  microscope  with  considerable  magni- 
fying powers.  The  image  seen  through  it  is  magnified 
about  three  hundred  times.^ 

'  The  lens  used  for  toy  micropliotographs  resembles  the  Stanhope  lens, 
but  is  not  cut  down  in  the  centre  to  form  a  diaphragm.  It  consists  simply  of 
a  cylinder  of  flint  glass,  or  long  plano-convex  lens  whose  focus  is  its  ovm. 
plain  surface,  to  which  the  photograph  is  attached  with  Canada  balsam. 

2  As  the  author  has  given  a  full  description  of  one  of  the  most  inte- 
resting and  important  applications  of  microphotography,  I  venture  to  append 
a  brief  supplementary  account  of  my  personal  experience  in  the  production 
of  minute  photographs. 

It  is  now  nearly  seventeen  years  since — after  a  series  of  experiments 
which  extended  over  twelve  months — I  found  out  a  method  by  which  the 
finest  results  could  *be  readily  obtained.  The  instrument  used  was  a  long 
camera  set  up  in  an  inclined  position,  in  a  dark  room,  with  its  upper  end 
projecting  through  an  aperture  in  the  window  so  as  to  command  a  clear 
northern  light.  The  negative  to  be  copied  was  placed  in  a  frame  at  the 
end  of  the  camera.  While  the  lower  extremity  of  the  camera  supported 
the  object-glass  of  a  microscope  fixed  in  a  sliding  tube  supplied  with  a 
coarse  and  fine  adjustment,  a  glass  stage  with  spring  clamp  was  also  added 
for  the  support  of  the  collodionised  plate.  Above  the  stage  there  was 
placed  an  ordinary  microscope  set  so  as  to  correspond  with  the  optical  axis 
of  the  instrument. 

The  first  great  difficulty  to  be  overcome  was  focussing.  To  use  any 
ordinary  semi-opaque  focussing  screen  would  have  been  labour  thrown  away, 
as  the  image  to  be  formed  was  not  larger  than  a  pin's  head  ;  I  therefore 
adapted  a  microscopic  glass  slip,  and  first  brought  the  specks  of  dust  on 
the-inner  side  of  the  glass  into  the  focus  of  the  microscope ;  it  was  then 
necessary  to  focus  the  image  cast  by  the  object-glass  on  the  same  dusty 
plane.  This  method,  however,  turned  out  to  be  useless.  As  I  was 
very  young  and  inexperienced  at  the  time,  I  was  completely  puzzled 
until  I    discovered    that    the  refraction    of    the   glass   slip  prevented  me 


MICROSCOPIC   DESPATCHES.  24 1 

The  production  of  microscopic  prints  requires  great 
ability  on  the  part  of  the  operator,  and  great  delicacy  in 
the  various  manipulations. 

from  finding  the  actual  focus.  The  focussing  slip  was  at  length  thrown 
aside,  and  I  determined  to  focus  the  tiny  image  in  air  without  a  screen, 
but  with  the  silken  hair  from  a  spiders  web  stretched  across  the  field  on 
the  glass  rim  of  the  stage,  and  on  the  same  plane  as  that  to  be  occupied 
by  the  sensitive  plate.  It  was  then  necessary  to  focus  the  microscope  to  the 
silken  thread,  and  afterwards  to  bring  the  tiny  image  to  the  corresponding 
plane.  This,  I  need  hardly  say,  proved  absolutely  satisfactory,  and,  more- 
over, when  the  focus  had  been  once  determined,  it  remained  unaltered 
for  an  indefinite  length  of  time.  The  ultimate  success  of  micro-photography 
(with  collodion)  depends,  greatly,  on  the  accuracy  of  focussing,  as  the 
1,000th  part  of  an  inch  of  variation  in  the  position  of  the  object-glass  throws 
the  instrument  out  of  adjustment.  One  object  in  using  a  glass  stage  and 
glass  supports  was  to  do  away  with  the  alteration  of  focus  caused  by  the 
expansion  and  contraction  of  brass  or  other  metal. 

The  mode  of  operating  which  I  followed  in  taking  the  photograph 
was  nearly  identical  with  that  of  taking  an  ordinary  wet  collodion  positive, 
with  one  or  two  modifications  very  simple  in  themselves,  but  at  first 
extremely  difficult  to  find  out.  By  using  an  ordinary  collodion  and  an  iron 
developer,  the  resulting  picture,  when  placed  under  the  microscope,  would  be 
so  coarse  in  texture  as  to  appear  nothing  more  than  a  patch  of  gravelly  soil. 

The  nitrate  of  silver  bath  was  of  the  common  strength,  first  rendered 
neutral,  and  then  slightly  acid  with  glacial  acetic  acid.  The  developer  was  a 
weak  aqueous  solution  of  pyrogallic  acid  with  glacial  acetic  acid,  but  no 
alcohol.  As  to  the  collodion,  1  could  use  almost  any  of  the  commercial 
samples,  provided  they  gave  a  tenacious  parchment-like  film.  But  one  of 
the  great  secrets  of  success  lay  in  the  time  which  the  sensitised  plate  was 
kept  in  the  silver  bath.  The  duration  of  dipping  was  suited  to  the  collodion 
for  certain  chemical  reasons,  which  I  have  not  space  in  this  note  to  discuss, 
nor  can  I  do  more  than  give  this  simple  outline  of  the  micro-photogiaphic 
instrument  and  its  manipulation. 

There  is  another  application  of  micro-photography  of  great  value  to 
the  microscopist.  It  consists  in  the  photographing  of  '  finders '  on  a  square 
space  of  one  inch  divided  into  squares  of  one  hundredth  of  an  inch.  Each 
square  contains  two  sets  of  numbers  from  the  unit  up  to  one  hundred 
running  in  opposite  directions  across  the  surface.    These  '  finders  '  are  all 

R 


242  THE   APPLICATIONS   OF   PHOTOGRAPHY. 

The  focussing,  which  is  easily  effected  with  impressions 
of  the  ordinary  size,  requires  the  employment  of  a  micro- 
scope when  the  image  thrown  on  the  surface  of  the 
ground  glass  is  of  such  a  very  small  size. 

The  usual  dark  slide  of  the  camera  is  replaced  by  a 
support  which  keeps  in  a  horizontal  position  a  plate  of 
collodionised  glass,  and  carries  besides  twenty  little 
object-glasses  intended  to  produce  as  many  microscopic 
reductions  of  the  negative.  Afterwards,  by  the  aid  of  a 
diamond  this  glass  plate  is  cut  into  twenty  pieces,  each 
containing  a  picture.  We  shall  confine  ourselves  to 
mentioning  these  difficulties  without  entering  into  full 
technical  details. 

During  the  war  the  processes  were  different,  especially 
in  magnifying  the  photographs  for  the  purpose  of  being 
read  in  the  besieged  capital. 

taken  in  a  mathematically  accurate  uniform  position  on  glass  slips  of  perfectly 
uniform  size.  Each  slip  fits  into  its  allotted  position  on  the  stage  of  all" 
well-formed  microscopes,  and  puts  it  in  the  power  of  the  microscopist 
to  determine,  so  to  speak,  the  longitude  and  latitude  of  a  single  diatom, 
or  group  of  diatomacese,  or  any  minute  object  that  may  come  within  the 
field  of  his  instalment.  But  this  is  not  all.  Should  the  microscopist 
make  a  discovery,  the  finder  enables  him  to  verify  it.  Let  us  suppose  that 
some  new  diatom  occupies  the  field  of  his  microscope.  It  is  a  minute 
object  quite  invisible  to  the  naked  eye,  and  most  difficult  to  find  among 
the  countless  groups  of  its  fellows.  But  the  student,  in  order  to  fix  its  posi- 
tion, removes  the  slip  from  the  stage  and  replaces  it  by  the  finder,  when  he 
at  on.ce  reads  its  number.  This  number  he  registers,  and  thus  places  it  in 
the  power  of  any  savant  to  whom  the  slip  may  be  sent,  to  hit  upon  the 
position  of  the  diatom  at  once,  by  using  his  finder,  bringing  the  number 
into  the  field  and  replacing  the  finder  by  the  microscopic  slip, — Ed. 


MICROSCOPIC   DESPATCHES.  243 


Thirty  or  forty  copies  of  the  microscopic  despatches 
were  usually  printed  and  sent  by  as  many  pigeons.  More 
than  one  hundred  thousand  of  them  were  thus  sent  to 
Paris  during  the  siege. 

As  soon  as  the  small  tube  was  received  at  the  telegraph 
office,  MM.  Cornu  &  Mercadier  proceeded  to  open  it  with 
a  knife.  The  photographic  films  were  carefully  placed  in 
a  small  basin  of  water  in  which  were  put  a  few  drops  of  am- 
monia. In  this  liquid  the  despatches  unrolled  themselves. 
They  were  then  dried  and  placed  between  two  plates  of 
glass.  It  only  then  remained  to  lay  them  on  the  stage  plate 
of  a  photo-electric  microscope.  The  preceding  engraving 
(fig.  58)  represents  one  of  these  interesting  meetings  for 
the  purpose  of  transcribing  the  microscopic  despatches. 

The  image  on  the  film  of  collodion  is  there  thrown 
upon  a  screen  by  means  of  a  photo-electric  apparatus, 
which  is,  in  fact,  a  very  powerful  magic  lantern.  The 
almost  invisible  letters  are  sufficiently  magnified  to  enable 
the  copyists  to  reproduce  them  on  paper. 

When  the  despatches  were  numerous  the  reading  of 
them  was  a  somewhat  slow  process,  but  as  each  film 
contained  a  great  number  of  pages  or  little  squares, 
they  could  be  divided  and  read  at  the  same  time  by 
the  use  of  several  microscopes. 

Messieurs  Cornu  and  Mercadier  carried  the  process  of 
R  2 


244  THE   APPLICATIONS   OF   PHOTOGRAPHY. 

reading  the  despatches  by  means  of  the  microscope  to 
great  perfection.  The  film  of  collodion  pressed  between 
two  glass  plates  was  placed  upon  the  stage  of  the  micro- 
scope to  which  a  mechanical  arrangement  gave  both  a 
horizontal  and  a  vertical  movement.  Each  part  of  the 
despatch  passed  slowly  over  the  field  of  the  microscope. 
The  characters  displayed  themselves  upon  the  screen 
sufficiently  magnified  to  be  read  and  copied.  The 
arrangement  and  process  of  reading  the  despatches 
lasted  about  four  hours  ;  it  required  besides  several  hours 
to  copy  them.  Messieurs  Cornu  and  Mercadier  tried  to 
photograph  the  characters  directly  as  enlarged  and 
thrown  upon  the  screen,  but  did  not  succeed  in  doing  so 
in  their  first  attempts. 

It  is  certain  that  improvements  in  the  process  would 
have  progressed  rapidly  had  not  the  severe  cold  of  the 
winter  caused  the  arrival  of  the  pigeons  to  become  more 
and  more  rare  during  the  siege. 

Though  details  concerning  these  birds  lie  beyond 
our  subject,  which  is  essentially  photographic,  we  do  not 
think  we  can  omit  making  a  few  remarks  about  them  ; 
for  having  described  the  letters,  it  is  only  right  to  say  a 
few  words  about  the  postmen. 

The  severity  of  the  season  is  not  the  sole  obstacle 
which  prevents  the  duties  of  the  messenger  birds  from 


MICROSCOPIC   DESPATCHES. 


245 


being  properly  performed  ;  they  are  exposed  to  other 
dangers  on  their  passages,  birds  of  prey  being  their  most 
formidable  enemies. 

Doubtless  among  the  many  carrier-pigeons  which  never 
.return  to  their  home,  there  are  a  certain  number  which 


Fig  59. 


CHINESE  WHISTLES   ATTACHED   TO  CARRIER-PIGEONS. 

have  been  the  victims  of  those  aerial  pirates,  the  hawks. 
The  Chinese,'  who  often  show  considerable  ingenuity  in 


^  When  in  Pekin  I  was  for  some  time  puzzled  by  the  musical  tones 
which  came  from  a  number  of  birds  whirling  in  circles  over  the  city.  The 
mystic  sounds  were  at  length  explained  to  me  by  a  Chinaman  who  owned 
pigeons  and  who  armed  them  with  the  bamboo  pipes  used  to  scare  awny 
birds  of  prey. — Ed. 


246  THE   APPLICATIONS   OF   PHOTOGRAPHY. 

the  plans  which  they  adopt,  have  invented  a  very  in- 
genious system  to  protect  the  carrier-pigeons,  which  are 
much  employed  in  the  Celestial  Empire,  from  the  birds 
of  prey.  They  attach  to  the  root  of  the  tail  of  the 
messenger  birds  a  set  of  very  light  bamboo  whistles,  as 
represented  by  fig.  59.  When  the  pigeon  flies,  the  air 
rushes  into  these  little  tubes  ;  this  produces  vibrations, 
causing  a  sharp  and  continued  sound.  If  the  birds 
travel  in  companies,  the  sets  of  whistles  with  which  they 
are  provided  produce  a  noisy  concert.  People  who  have 
lived  for  some  time  in  China,  and  especially  at  Pekin, 
report  that  in  the  country  they  have  often  heard  the 
whistling  and  booming  produced  by  these  little  tubes 
of  bamboo  belonging  to  the  carrier-pigeons,  without  at 
first  being  able  to  account  for  the  unexpected  sound 
which  seemed  to  descend  from  the  skies. 

It  seems  to  us  that  this  process  deserves  attention. 
Everything  should  be  done  to  perfect  the  organisation  of 
the  aerial  post,  which  at  present  occupies  the  attention 
of  many.  We  hope  that  this  organisation  may  soon  be 
ready  to  work,  and  that  the  history  of  the  pigeons  of 
the  siege  may  be  an  encouragement  to  future  breeders  of 
these  interesting  and  useful  birds. 

We  should  not  forget  that  in  the  fatal  hour  when 
France  was  invaded  by  her  enemies,  photography  com- 


KiG.  60  I  I'a^'c  247 

DEPARTURE    OF   CARRIER    PIGEONS    FROM    THE    CHAMPS-ELVS^ES,    PARIS. 


MICROSCOPIC  DESPATCHES.  24/ 

pleting  the  wonderful  services  rendered  by  the  pigeons, 
was  of  great  advantage  to  thousands  of  the  besieged, 
imprisoned  during  five  months  by  the  German  armies. 

Let  us  hope  that  the  teachings  of  the  past  will 
be  fruitful  in  the  future,  and  that  if  France  is  again 
engaged  in  one  of  these  bloody  conflicts,  the  carrier- 
pigeons  will  play  their  modest  part  and  give  new  assis- 
tance. This  time  we  would  fain  believe  they  will  only  be 
the  messengers  of  victory  and  good  news. 

Breeding  and  training  pigeons  is  the  necessary  com- 
plement to  microscopic  photography,  as  employed  in 
making  up  and  forwarding  despatches  during  time  of 
war. 

At  present  these  useful  winged  messengers  are  not 
neglected,  and  quite  recently  an  attempt  has  been  made 
to  encourage  the  breeding  of  them  by  valuable  prizes 
offered  for  competition.  During  the  year  1873,  the 
people  of  Paris  have  shown  their  approval  of  these  en- 
couragements by  attending  the  departures  of  the  pigeons 
which  take  place  before  the  Palace  of  Industry  from 
time  to  time  (fig.  60).  Such  experiments  cannot  be  too 
much  encouraged.  Carrier-pigeons  are  the  safest  bearers 
of  these  microscopic  despatches,  which  convey  to  the 
besieged  detailed  news  and  explicit  orders. 

In  certain  cases  very  remarkable  results  were  attained 


248  THE   APPLICATIONS   OF    PHOTOGRAPHY. 

by  means  of  the  aerial  post.  Here  is  an  example  men- 
tioned by  M.  Dagron  : — *  When  nothing  interfered  with 
the  flight  of  the  pigeons,'  says  this  talented  operator,  *  the 
rapidity  of  the  photographic  correspondence  was  truly 
marvellous.  I  can  myself  give  an  example.  Wanting 
some  chemicals,  especially  gun  cotton,  which  I  could  not 
procure  at  Bordeaux,  I  ordered  them  by  pigeon  despatch 
from  Messrs.  Poulenc  and  Wittmann,  of  Paris,  on  January 
18,  1871,  begging  them  to  forward  them  by  first  balloon. 
On  January  24th  the  articles  were  delivered  to  me 
in  Bordeaux.  The  pigeon  had  only  taken  twelve  hours 
to  pass  from  Poitiers  to  Paris.'  The  electric  telegraph 
and  railway  could  not  have  done  better. 

This  admirable  use  of  microscopic  photography, 
bringing  to  the  aerial  post  by  balloons  and  pigeons  the 
indispensable  complement  of  light  messages,  is  a  fine 
example  of  the  close  correlation  which  unites  the 
different  branches  of  modern  science,  and  which  enables 
them  at  a  given  moment  to  co-operate  towards  the  same 
result. 


249 


CHAPTER  VII. 

ASTRONOMICAL  PHOTOGRAPHY. 

CELESTIAL  PHOTOGRAPHY — DIFFICULTIES  OF  ASTRONOMICAL  PHOTO 
GRAPHIC  OPERATIONS — MESSRS.  WARREN  DE  LA  RUE,  RUTHERFURD, 
GRUBB,  ETC.—  THE  LUNAR  MOUNTAINS-  THE  SPOTS  ON  THE  SUN, 
ETC. — IMPORTANCE  OF  PHOTOGRAPHIC  DOCUMENTS  FOR  THE  HISTORY 
OF    THE    HEAVENS. 

Photography  furnishes  inestimable  resources  to  all 
the  sciences.  We  have  seen  that  it  places  under  the  eyes 
of  the  naturalist  the  enlarged  images  of  the  grains  of  the 
pollen  of  a  flower,  infusoria,  and  of  forms  of  vegetable 
and  animal  life  invisible  to  the  naked  eye. 

Meteorology,  as  we  shall  show  in  the  sequel,  makes 
use  of  it  to  register  with  mathematical  precision,  with  a 
constancy  which  nothing  interrupts,  all  the  variations  of 
the  barometer,  of  the  thermometer,  and  of  the  magnetic 
needle.  Geology  finds  it  a  useful  assistant  in  repro- 
ducing, with  an  exactness  which  nothing  can  approach, 
the  inclinations  of  the  various  strata  it  would  study.  The 
engineer  employs  it  like  a  mirror,  in  which  he  sees  from 
day  to  day  the  state  of  the  works  he  is  employed  in 
executing. 


250  THE   APPLICATIONS   OF    PHOTOGRAPH^. 

The  applications  of  photography  to  astronomy  in  the 
study  of  the  heavens  are  not  less  valuable.  They 
furnish  a  remarkable  assistance  to  those  who  devote 
themselves  to  the  task  of  sounding  the  depths  of  the 
firmament. 

Though  it  is  true  that  these  applications  are  new 
and  recent,  it  may  be  remembered  that  they  were 
foreseen  by  Arago  from  the  time  of  Daguerre.  In  his 
notice  of  the  Daguerreotype,  the  illustrious  Perpetual 
Secretary  of  the  Academy  of  Sciences  reports  with 
admiration  that  the  inveiitor  of  the  diorama,  at  his 
request,  had  obtained  an  image  of  the  moon  on  the 
sensitive  silver  plate. 

To  reproduce  at  the  present  day  the  images  of  the 
celestial  orbs  by  photography,  the  operator  may  employ 
one  of  the  powerful  telescopes  which  are  to  be  found  in 
all  the  principal  observatories  of  the  civilised  world. 

It  is  indispensable  to  make  use  of  a  reflecting  tele- 
scope having  a  speculum  formed  of  glass,  silvered 
according  to  Foucault's  process.  This  instrument  is 
achromatic,  that  is,  its  optical  coincides  with  its  chemical 
focus.    The  focussing  of  it  therefore  presents  no  difficulty. 

The  telescope  thus  constructed  should  be  mounted 
equatorially,  as  astronomers  say,  i.e.  supplied  with  a 
moving  power  which  during  the  operation  follows  exactly 


ASTRONOMICAL  PHOTOGRAPHY.       251 

the  motion  of  the  celestial  body  the  image  of  which  is 
being  taken.  This  movement,  also,  must  be  in  the 
plane  of  the  celestial  equator— the  same  as  that  in  which 
the  star  or  planet  moves. 

When  an  astronomer  wishes  to  obtain  the  photograph 
of  celestial  bodies  by  means  of  Foucault's  reflecting 
telescope,  he  removes  from  the  instrument  the  eye-piece 
generally  used  and  replaces  it  by  a  double  ring,  in  the 
central  part  of  which  is  fixed  the  collodionised  glass- 
plate  intended  to  receive  the  luminous  impression.  In 
order  to  focus  the  instrument  the  collodionised  glass  is 
replaced  by  a  piece  of  ground  glass  and  moved  back- 
ward and  forward  until  the  image  is  sharply  defined.  At 
this  moment  the  movable  screen  is  quickly  withdrawn  ; 
the  sensitive  surface  is  exposed  ;  it  receives  directly  the 
luminous  rays  v/hich  reproduce  faithfully  the  image  of 
the  celestial  body  millions  of  miles  distant  from  our 
humble  planet.  The  negative  is  fixed  by  the  ordinary 
means,  and  will  print  an  unlimited  number  of  positive 
impressions  on  photographic  paper. 

Mr.  Warrren  de  la  Rue  is  one  of  the  astronomers  who 
first  attained  the  most  perfect  results  of  photographic 
astronomy.  He  managed  to  take  an  impression  of  the 
constellation  of  the  Pleiades  of  remarkable  sharpness,  but 
he  did  not  succeed  in  getting  an  impression  of  any  of  the 


2  52  THE   APPLICATIONS   OF   PHOTOGRAPHY. 

nebulae.  These  clouds  of  suns  are  scattered  through 
the  heavens  at  such  distances  from  our  humble  spheroid 
that  the  human  mind,  staggered  when  it  would  regard 
them,  feels  itself  almost  powerless  to  comprehend  these 
measures  of  immensity. 

When  the  sky  is  clear,  when  no  cloud  mars  the 
purity  of  the  vault  of  heaven,  the  photographic  im- 
pressions of  the  planets  give  fairly  satisfactory  results ; 
but  the  image  is  never  perfectly  sharp  and  distinct. 
These  orbs,  endowed  with  a  weak  actinic  power,  only  leave 
an  uncertain  trace  on  the  negative  ;  the  fixed  stars,  true 
luminous  points  placed  in  the  heavens  at  enormous 
distances  from  the  earth  and  from  our  observatories, 
leave  upon  the  coUodionised  glass  the  trace  of  an 
excessively  thin  line,  and  sometimes  it  is  very  irregular  if 
the  atmosphere  of  the  earth  is  overcharged  with  vapour. 
After  having  fixed  on  a  photographic  plate  the  trace 
of  these  stars,  it  is  necessary  to  assist  the  eye  with  a 
good  microscope  to  discover  it.  Our  eye  is  as  power- 
less to  perceive  it  without  the  help  of  an  instrument  as 
we  are  to  appreciate  the  greatness  or  the  real  distance  of 
these  suns  lost  in  the  depth  of  the  heavens. 

In  spite  of  the  difficulties  which  the  photography  of 
the  planets  offers,  Mr.  Warren  de  la  Rue,  thanks  to 
persevering    labours   and    ingenious   combinations,   has 


ASTRONOMICAL   PHOTOGRAPHY.  253 


succeeded  to  a  certain  extent.  This  learned  astronomer 
succeeded,  by  the  aid  of  an  equatorial  mechanism  ad- 
mirably regulated,  in  keeping  the  image  of  the  moving 
star  for  several  minutes  in  the  centre  of  the  field  of 
view  of  the  telescope  which  moved  along  with  it,  and  his 
efforts  were  crowned  with  legitimate  success. 

He  was  able  to  take  the  photograph  of  Jupiter  with 
his  parallel  zones.  Nor  has  it  been  beyond  the  powers  of 
this  talented  operator  to  fix  upon  the  collodion  the 
rough  surface  of  the  planet  Mars  and  the  mysterious  ring 
of  Saturn. 

If  the  photography  of  planets  offers  serious  difficulties, 
that  of  the  moon,  which  alters  its  place  in  the  heavens 
much  more  rapidly,  presents  obstacles  still  greater ;  but 
great  though  they  be,  they  have  been  surmounted  by 
Secchi,  De  la  Rue,  Rutherfurd,  Grubb,  and  some  other 
distinguished  astronomers,  as  skilled  in  the  manage- 
ment of  photographic  apparatus  as  in  their  knowledge 
of  the  heavens. 

We  place  before  the  eyes  of  our  readers  the  facsimile  of 
the  photograph  of  a  very  interesting  region  of  our  satellite. 
Our  engraving  has  the  merit  of  reproducing  exactly  the 
appearance  of  the  impression  obtained  by  the  English 
astronomer  (fig.  61). 

Some  years  ago  Mr.  Grubb  succeeded  in  photograph- 


254  THE   APPLICATIONS   OF    PHOTOGRAPHY. 

ing  the  moon  as  correctly  as  if  she  had  been  sitting  for  her 
portrait  in  his  own  studio.  Only  as  the  Dublin  astrono- 
mer could  not  utter  the  usual  caution — Don't  move — it 
was  necessary  that  the  telescope  at  the  focus  of  which 
the  image  w^as  to  be  fixed  should  move  at  exactly  the 

Fig.  6 1. 


LUNAR    MOUNTAINS.       AFTER    A    PHOTOGRAPH    BY    MR.  WARREN    DE   LA    Rl  E. 

same  rate  as  the  sitter.     Mechanically  such  a  result  is 
not  easy  to  attain  with  rigorous  correctness. 


ASTRONOMICAL   PHOTOGRAPHY.  255 

The  great  telescope  constructed  by  Mr.  Grubb 
for  the  Government  observatory  at  Melbourne  is  a 
marvel  of  mechanism.  The  speculum  is  about  46 
inches  in  diameter,  with  a  focal  length  of  30  feet, 
and  its  weight,  including  all  its  mountings,  is  about  two 
tons.  The  tube  is  surrounded  by  a  trellis-work  of 
flat  iron,  but  it  is  chiefly  composed  of  bars  of  steel  firmly 
fixed  to  solid  rings  of  iron,  the  whole  weighing  about 
ten  tons.  To  render  the  movement  as  easy  as 
possible,  all  the  bearings  are  supported  by  an  ap- 
paratus to  prevent  friction.  This  telescope  is  so  easy 
to  manage,  notwithstanding  its  enormous  dimensions,  that 
two  persons  can  turn  it  round  either  vertically  or  hori- 
zontally in  forty-five  seconds. 

This  instrument,  which  takes  in  the  whole  hemisphere, 
is  put  in  motion  by  an  excellent  clock.  In  the  course  of 
the  year  1869  Mr.  Grubb  presented  to  the  French  Photo- 
graphic Society  photographs  of  the  moon  taken  by  the 
aid  of  this  huge  telescope,  in  a  camera  mounted  at  the 
end  of  the  trellis-work  tube.  The  time  of  exposure 
varied  from  half  a  second  to  two  seconds,  the  brilliantly- 
lighted  part  of  the  moon  requiring  a  shorter  exposure 
than  the  parts  in  the  neighbourhood  of  the  dark  side. 

Up  to  this  time,  as  we  have  said,  Mr.  de  la  Rue  in 
England    and   Secchi    in    Rome   had  alone  succeeded 


256  THE   APrLICATIONS   OF    PHOTOGRAPHY. 

in  producing  photographs  of  the  moon  worthy  of  the 
attention  of  natural  philosophers  or  of  astronomers. 

The  impressions  obtained  by  these  gigantic  instru- 
ments r.f  Mr.  Grubb  in  the  serene  atmosphere  of  Australia 
have  greatly  surpassed  the  highest  efforts  of  European 
art. 

It  is  impossible  to  avoid  a  certain  emotion  in  con- 
templating the  negative  of  a  lunar  photograph,  in  admiring 
the  raised  appearance  of  the  mountains  of  our  satellite, 
and  tracing  upon  the  collodion  the  dark  obscurities 
formed  by  its  valleys.  It  is  quite  certain  that  it  is 
mathematically  correct,  for  it  is  the  light  from  its  surface 
that  has  winged  its  flight  to  our  globe  to  print  the 
picture  of  the  rugged  peaks,  the  craters,  the  strange 
hollows  which  appear  on  the  surface  of  the  orb  of  night. 

Marvellous  result  of  science,  which  takes  the  minute 
counterpart  of  the  silvery  and  mysterious  disc  suspended 
so  far  from  us  in  the  dark  azure  of  the  firmament ! 

There  has  been  rapid  and  important  progress  in  this 
fertile  field.  Mr.  Rutherfurd  has  lately  obtained  photo- 
graphs of  the  moon  of  the  greatest  merit.  Some  impres- 
sions were  presented  to  the  Academy  of  Sciences  in 
November  1872,  by  M.  Faye,  who,  in  offering  these 
remarkable  specimens,  gave  some  details  of  the  highest 
interest,  which  we  are  happy  to  borrow  from  him  : — 


ASTRONOMICAL  PHOTOGRAPHY.  257 

*  These  impressions,  striking  marks  of  the  progress 
which  astronomical  photography  has  made  in  the 
United  States,  have  been  obtained  by  means  of  a 
lens  of  13  inches'  aperture,  specially  achromatised. 
From  the  negative,  which  was  about  four  inches  in 
diameter,  a  positive  was  taken  of  the  same  size,  and  this 
was  then  magnified  by  a  powerful  solar  microscope.  The 
exposure  of  the  original  negatives  varied  from  one 
quarter  of  a  second  at  full  moon  to  two  seconds  at  the 
first  and  last  quarters. 

*  The  photographic  lens  was  m.oved  during  the  time  of 
exposure  at  the  same  rate  as  the  apparent  motion  of  the 
moon,  by  clockwork  of  great  accuracy. 

'A  glance  at  these  magnificent  impressions  is  sufficient 
to  make  the  service  they  may  render  to  lunar  geology 
appreciated. 

'  The  luminous  lines,  like  cracks  forming  parts  ot 
a  great  circle,  intersect  one  another  at  angles  which 
it  is  possible  to  measure  with  a  certain  amount  of  exact- 
ness. By  the  aid  of  an  outline  map  on  which  are  marked 
the  lines  of  latitude  and  longitude,  calculated  pre- 
viously so  as  to  correspond  with  the  particular  phase  of 
the  moon,  and  drawn  upon  a  sheet  of  transparent  paper, 
and  then  applied  to  these  beautiful  maps,  the  geome- 
trical elements  of  these    arcs  in  relation  to  the    lunai^ 

S 


258  THE   APPLICATIONS   OF   PHOTOGRAPHY. 

equator  can  be  obtained.  The  circles,  the  craters,  and 
even  the  smallest  circular  hollows  which  the  surface 
of  the  moon  exhibits  in  great  numbers,  are  there 
represented  on  a  large  scale  with  a  startling  fidelity 
which  no  printed  chart  could  equal.  One  can  there  study 
at  leisure  the  numerous  varieties  of  these  different  objects 
so  similar  at  first  sight  to  our  extinct  volcanoes,  and  yet 
so  different  in  some  respects  from  their  terrestrial  repre- 
sentatives. Photography  shows  the  heights  of  these 
mountains  by  showing  the  length  of  their  shadows  as 
well  as  their  horizontal  dimensions. 

Among  the  lunar  formations  best  represented  by 
photography  are  what  are  called  seas,  the  want  of 
light  or  rather  the  dull  colour  of  which  strikingly  con- 
trasts with  the  brightness  of  the  mountainous  parts.  One 
is  struck  by  their  aspect  quite  as  vividly  as  by  the  direct 
inspection  of  the  moon,  with  the  idea  that  there  are  before 
you  vast  discharges  of  fluid  matter,  which  have  covered  up 
the  previous  inequalities  of  the  surface,  leaving  here  and 
there  on  its  coasts  some  vestiges  of  primitive  cycles. 

If  photographs  of  the  moon  are  fruitful  in  informa- 
tion, those  of  the  sun  are  not  less  rich  in  their  teachings  ; 
and  the  spots  which  sully  the  purity  of  the  orb  of  day 
have  been  imprinted  on  the  glass  plate  of  the  camera. 

Celestial  photography  has  recently  been  applied   at 


ASTRONOMICAL   PHOTOGRAPHY.  259 

Harvard  College  in  the  United  States  to  the  double  stars, 
in  order  to  determine  by  micrometric  measurement  their 
relative  angle  of  position  and  distance. 

In  the  photographic  reproduction  of  the  stars  recently 
undertaken  by  Mr.  Rutherfurd,  it  has  been  found  neces- 
sary to  take  special  precautions  with  the  sensitive  plate, 
so  as  to  distinguish  these  impressions  from  accidental 
markings  on  the  film  of  collodion.  To  prevent  any  chance 
of  error,  Mr.  Rutherfurd  takes  a  double  image  of  each 
luminous  body  by  stopping  the  motion  of  the  telescope 
for  about  half  a  minute  between  the  first  and  second  ex- 
posure, so  that  each  star  is  represented  by  two  con- 
tiguous points  on  the  negative,  a  peculiarity  which  dis- 
tinguishes them  from  any  spot  formed  accidentally  on  the 
film.  By  this  means  a  very  correct  though  very  delicate 
map  of  the  heavens  is  obtained,  from  which  trustworthy 
measurements  may  be  made.  Professor  Peirce  says  with 
justice  this  addition  to  astronomical  research  is  a  step 
which  leaves  far  behind  it  all  that  has  been  previously  ac- 
complished. Photographs  preserve  for  comparison  with 
future  researches  the  exact  relative  positions  of  the  stars 
at  the  present  time.  The  photographs  once  taken  con- 
stitute indisputable  facts  beyond  the  influence  of  any 
personal  defect  of  observation,  and  provide  for  future 
ages  the  present  actual  position  of  the  stars. 


26o  THE   APPLICATIONS   OF    PHOTOGRAPH  V. 

Mr.  Asaph  Hall,  who  has  taken  part  with  Professor 
Bond  in  measuring  the  photographic  images  as  well  as  in 
the  calculations  of  these  measurements,  has  quite  recently 
submitted  the  photographic  method  to  severe  tests 
in  order  to  determine  its  value  in  its  application  to  the 
observation  of  the  transit  of  Venus.  He  seems  not  to 
approve  of  photography  as  applied  to  observations 
of  the  stars  from  its  want  of  rapidity;  but  he  admits 
that  in  the  case  of  an  eclipse  of  the  sun,  or  of  the 
passage  of  a  planet  across  the  sun's  disc,  it  possesses  very 
great  advantages,  especially  for  the  observation  of  the 
exterior  or  interior  contacts  of  the  planet  with  the  sun's 
limb,  and  that  any  error  to  which  it  may  be  liable  is 
worthy  of  the  most  serious  investigation.  The  observa- 
tion of  the  contact  is  uncertain  in  consequence  of  the 
irradiation  ;  it  only  lasts  for  an  instant,  and  should 
the  observer  fail  to  notice  it,  the  registration  of  the 
phenomenon  is  irredeemably  lost  at  that  particular 
station,  and  all  the  long  and  expensive  preparations  are 
rendered  useless. 

On  the  other  hand,  when  the  sky  is  clear  a  photo- 
graphic image  can  be  obtained  in  an  instant,  and  can  be 
repeated  during  the  whole  course  of  the  transit;  and 
when  even  the  contacts  have  not  been  caught,  results  not 
less  valuable  may  be  obtained  if  the  data  collected  on 


ASTRONOMICAL  PHOTOGRAPHY.  26 1 


the  photographic  plates  can  be  correctly  calculated.  Of 
this  we  shall  shortly  show  the  perfect  practicability.  We 
may  announce  for  certain  that  the  transit  of  Venus  will  be 
depicted  by  photography,  for  in  England,  in  France,  in 
Russia,  and  in  America,  much  activity  is  displayed  in 
making  preparations  to  obtain  photographic  pictures  of  it.' 

Nothing  can  more  solidly  establish  the  right  of  photo- 
graphic observations  to  be  considered  one  of  the  most 
important  aids  of  scientific  research  than  the  accounts 
of  the  last  eclipses  of  the  sun.  It  will  be  recol- 
lected that  in  i860  for  the  first  time  the  solar  origin  of 
the  protuberances  was  put  beyond  doubt  solely  by  photo- 
graphy, which  preserved  a  faithful  representation  of  the 
movement  of  the  moon  in  relation  to  these  protuber- 
ances. 

The  photographs  of  Tennant  at  Guntoor,  and  of 
Vogel  at  Aden  in  1868,  and  those  also  of  the  American 
astronomers  at  Burlington  and  at  Ottumwa,  Iowa,  in  1869, 
under  the  superintendence  of  Professors  Morton  and 
Mayer,  have  fully  confirmed  these  conclusions. 

It  was  also  in  the  same  manner  that  the  great  pro- 
blem of  the  solar  origin  of  that  part  of  the  corona  which 

•  As  the  reader  is  doubtless  well  aware,,  the  attempts  to  photograph 
the  Transit  were  eminently  successful,  especially  with  the  daguerreotype 
-process. 


262  THE   APPLICATIONS   OF   PHOTOGRAPHY. 

extends  more  than  a  million  of  miles  beyond  the  body  of 
the  sun  was  definitively  solved  by  the  photographic 
observations  of  Colonel  Tennant  and  Lord  Lindsay  in 
1 87 1,  after  having  for  many  years  furnished  matter  for 
numerous  discussions. 

If  photography,  as  will  be  seen  by  these  striking  facts, 
now  renders  great  services  to  astronomy,  it  will  in  all  pro- 
bability render  yet  greater  in  the  immediate  future,  for  it 
is  still  unable  to  depict  all  the  celestial  bodies. 

*  The  nebulae  and  the  comets,'  says  Mr.  Warren  de 
la  Rue,  'have  not  fallen  into  the  domain  of  this  art, 
though  perhaps  no  branch  of  astronomy  would  have  more 
to  gain  if  we  could  succeed  in  extending  this  mode  of 
observation  to  these  bodies.  In  theory,  and  even  in 
practice,  there  is  no  limit  to  the  sensitiveness  of  a  photo- 
graphic plate.  At  the  same  time,  there  still  exist  great 
difficulties  in  photographing  the  planets,  which  it  is 
necessary  to  overcome  before  photography  can  for  any 
special  purpose  reproduce  their  phases  and  their  physical 
characteristics,  but  even  in  this  also  there  is  great  hope  of 
final  success.  The  chief  obstacle  to  success  arises  from 
atmospheric  currents  which  continually  change  the  posi- 
tion of  the  image  on  the  sensitive  plate.  The  structure 
of  the  sensitive  film  is  also  a  cause  of  trouble  with  very 
small  objects,  though  a  photograph  taken  at  Cranford  some 


ASTRONOMICAL  PHOTOGRAPHV.       26^ 

time  ago  of  the  occultation  of  Saturn  by  the  moon,  shows 
the  ring  of  the  planet  in  such  a  manner  as  to  afford  great 
hopes  for  the  future.' 

No  doubt  science  will  succeed  in  triumphing  over 
these  obstacles,  and  photography  applied  to  the  whole 
heavens  will  crown  the  edifice  of  modern  astronomy. 

Some  astronomers,  however,  are  not  of  this  opinion, 
and  we  believe  it  may  be  useful  to  state  the  opinions  ot 
the  venerable  Maedler,  formerly  director  of  the  Obser- 
vatory of  Dorpat,  on  the  subject  of  photographic 
astronomy : — '  The  greater  number  of  those  who  hear 
me,'  said  the  great  astronomer,  in  a  lecture  given  in  1868, 
*  may  still  remember  that  immediately  after  the  discovery 
of  photography  we  heard  hopes  expressed  which  re- 
sembled nothing  so  much  as  those  of  Descartes  and  his 
contemporaries  after  the  discovery  of  the  astronomical 
telescope.  They  compassionated  the  unfortunate  philo- 
sophers who  had  passed  all  their  lives  without  interrup- 
tion in  observing,  in  measuring,  and  in  drawing. 

*  Not  only  would  the  same  thing,  they  said,  be  done 
without  trouble  and  in  much  less  time,  but  the  results 
obtained  would  be  much  superior,  much  more  exact,  and 
much  more  detailed  than  formerly.  What  has  taken  me 
seven  years,  the  determination  of  the  extent  of  the  sur- 
face of  the  moon,  would  be  better  done  in  seven  seconds. 


264  THE  APPLICATIONS   OF   PHOTOGRAPHY. 

Now  thirty  years  have  elapsed  since  the  discovery  of 
Daguerre,  how  many  of  these  ambitious  hopes  have  been 
fulfilled  ? 

'  Warren  de  la  Rue,  in  England,  and  William  Cranch 
Bond,  in  America,  have  courageously  put  their  hands  to 
the  work.  They  have  adapted  powerful  astronomical 
telescopes  to  photographic  apparatus,  they  have  also 
succeeded  in  giving  to  their  instruments  a  motion  corre- 
sponding to  that  of  the  celestial  bodies,  of  which  they 
propose  to  produce  the  image  during  the  short  time 
necessary  for  the  production  of  the  impression. 

'  Thus  the  moon  has  been  photographed  in  her 
different  phases,  but  the  details  are  still  inferior  to  those 
which  an  able  observer  can  determine.  Bond  has  been 
engaged  with  the  fixed  stars  ;  he  made  use  of  an  astro- 
nomical telescope  which  enabled  him  to  perceive  the  stars 
of  the  fourteenth  magnitude,  but  he  was  only  able  to 
obtain  weak  and  scarcely  visible  images  of  those  of  the 
fifth  magnitude, 

'  We  could  mention,  it  is  true,  very  valuable  pictures 
which  we  owe  to  astronomical  photography  ;  but  it  is  not 
the  details  of  the  starry  heavens  which  can  be  acquired 
and  preserved  in  this  manner,  but  the  phenomena  con- 
nected with  objects  long  known  and  giving  a  powerful 
light. 


ASTRONOMICAL   PHOTOGRAPHY.  265 


*  I  shall  mention  in  the  first  place  the  spots  on  the 
sun,  the  representation  of  which  only  requires  the  smallest 
fraction  of  a  second,  and  which  have  been  produced 
with  great  exactness.  But,  even  in  this^case,  details  have 
not  been  obtained,  such  as  good  observers,  accustomed  to 
these  phenomena,  have  been  able  to  produce,  but  there 
is  obtained,  what  is  very  important  in  this  case,  an  image 
of  the  sun  at  a  specified  moment,  and,  if  we  may  be  per- 
mitted to  use  an  expression  of  Sir  John  Herschel,  we 
compel  the  sun  to  write  its  own  history. 

*  These  experiments  will  be,  or,  to  speak  more  cor- 
rectly, have  already  been,  very  useful  in  total  eclipses  of 
the  sun.  There  is  no  draughtsman,  however  expeditious 
he  might  be,  who  could,  during  two  or  three  minutes, 
the  ordinary  duration  of  the  phenomenon,  do  what  Warren 
de  la  Rue  did  in  Spain  at  the  last  eclipse  of  the  sun, 
because,  if  everything  has  been  prepared,  there  can  be 
obtained  not  only  three  but  twelve  or  fifteen  images  of 
a  phenomenon  which  passes  away  so  rapidly. 

*  As  for  the  planets,  even  the  larger  ones,  photography 
is  of  little  use,  and  will  teach  us  very  little  that  is  new. 
It  will  be  of  still  less  use  when  applied  to  the  fixed 
stars.  The  groups  of  the  Pleiades  and  of  Orion  have 
been  photographed,  and  these  constellations  may  cer- 
tainly be  recognised  in  the  images  obtained,  but  a  good 


266  THE   APPLICATIONS   OF   PHOTOGRAPHY. 

eye,  even  without  the  aid  of  lenses,  will  see  more  in  the 
heavens  than  is  shown  by  photography.' 

We  have  considered  it  right  to  repeat  these  severe 
criticisms  of  Maedler  without  altogether  admitting  their 
correctness.  We  think,  on  the  contrary,  that  photography 
is  one  of  the  great  resources  of  modern  astronomy. 

There  is  nothing  so  hurtful  or  so  fatal  to  progress, 
says  Mr.  Warren  de  la  Rue,  as  false  data,  because  they 
are  sometimes  perpetuated  for  ages.^ 

The  prodigies  accomplished  by  modern  opticians 
will  be  continued  by  our  descendants,  and  the  magnifi- 
cent telescopes  of  our  observatories,  which  diminish  the 
apparent  distance  of  the  moon  to  such  an  extent  that 
we  can  now  study  the  constitution  of  our  satellite  as  if  it 
were  at  a  less  distance  than  three  hundred  miles,  are 
only  as  yet,  we  cannot  doubt,  specimens  of  the  infancy 

*  It  cannot  be  denied  that  a  photographic  impression  of  any  object  is 
infinitely  inferior  to  the  object  as  we  see  it  with  the  naked  eye,  whether 
the  object  be  celestial  or  terrestrial.  Nevertheless,  photography  has  already 
done  much,  and  is  full  of  the  highest  promise  of  future  achievements  as 
the  only  known  means  by  which  may  be  preserved  an  absolutely  trustworthy 
register  of  many  of  the  most  important  phenomena  of  the  heavens.  It 
has  furnished  the  astronomer  with  charts  of  the  moon  ;  the  phenomena 
connected  with  solar  eclipses  ;  the  positions  of  the  spots  on  the  sun's  disc 
at  certain  fixed  dates  ;  the  spectra  of  heavenly  bodies,  showing  in  unerring 
lines  the  presence,  in  their  luminous  envelopes,  of  certain  elements  which 
are  known  to  us.  Without  the  aid  of  photography,  the  lines  in  the  solar 
spectrum  could  not  have  been  fully  observed,  as  the  photograph  reveals 
many  lines  which  are  invisible  to  the  naked  eye. — Ed. 


ASTRONOMICAL   PHOTOGRAPHY.  26/ 

of  an  art  which  reckons  among  its  founders  GaHleo  and 
Newton 

When  the  science  of  astronomical  optics  has  accom- 
plished still  more,  photography,  closely  following  its 
footsteps,  will  produce  marvels  of  which  the  boldest 
imagination  can  hardly  have  a  suspicion.  *  There  is  no 
limit  to  the  sensitiveness  of  a  photographic  plate,' 
we  may  say  at  present  with  an  eminent  astronomer ; 
consequently  the  images  of  the  orbs  of  heaven  fixed  in 
the  focus  of  the  camera  will,  perhaps,  permit  us  to  study 
the  most  minute  details  of  the  geology  of  the  planetary 
bodies. 

If  it  be  true,  as  Leibnitz  says,  that  the  present  is  big 
with  the  fate  of  the  future,  we  shall  comprehend,  by  the 
importance  of  results  already  obtained,  what  we  have  a 
right  to  expect  may  be  attained  by  the  astronomers  of 
the  future. 


268  THE  APPLICATIONS  OF  PHOTOGRAPHY. 


CHAPTER  VIII. 
PHOTOGRAPHIC  REGISTERING  INSTRUMENTS. 

IMPORTANCE  OF  REGISTERING  INSTRUMENTS — PHOTOGRAPHIC  BARO- 
METERS AND  THERMOMETERS — THE  REGISTRATION  OF  THE  VIBRA- 
TIONS OF  THE  MAGNETIC  NEEDLE — RONALD's  PHOTO-ELECTROGRAPH 
— PHOTOGRAPHIC  PHOTOMETRY — PHOTOGRAPHY  OF  COLUMNS  OF 
WATER  RAISED  BY  A  TORPEDO — OF  THE  PHENOMENA  OF  THE 
INTERFERENCE   OF   THE    RAYS    OF   THE    SPECTRUM. 

Among  the  physical  sciences  there  are  some,  of  which 
the  progress  is,  so  to  say,  intermittent,  which  burst  out 
into  veritable  revolutions  which  suddenly  transform  them; 
there  are  others,  where  great  events  are  rare,  where  the 
long-continued  patience  of  the  observer  is,  to  a  certain 
extent,  a  substitute  for  the  inspiration  originating  ac- 
cidentally in  the  brain  of  an  inventive  genius. 

Chemistry  has  had  its  Lavoisier,  who,  by  the  theory 
of  combustion,  by  the  analysis  of  the  atmosphere,  sud- 
denly marked  a  new  era  in  this  fertile  branch  of  human 
knowledge. 

Physical  science  has  had  its  Volta,  who  opened 
to  it  a  new  horizon  by  originating  the  electric  pile.      But 


PHOTOGRAPHIC   REGISTERING  INSTRUMENTS.      269 

there  are  other  sciences  where  such  progress  cannot  be 
suddenly  manifested. 

Meteorology,  for  example,  which  has  for  its  object  to 
study  the  laws  of  the  mechanism  of  the  atmosphere, 
ought  to  determine  every  day  the  temperature,  the 
humidity  of  the  air ;  note  the  variations  of  the  baro- 
meter, the  oscillations  of  the  magnetic  needle  ;  the  domain 
in  which  it  acts  is  not  that  of  rapid  conquests ;  a  science 
of  observation,  it  cannot  expect  anything  from  the  for- 
tunate accidents  which  sometimes  occur  when  making 
experiments. 

The  work  of  those  who  devote  themselves  to  it  con- 
sists essentially  in  gathering  up  each  day  and  every  hour 
rigorously  exact  lists  of  figures  ;  the  hope  which  animates 
them  is  to  see  stations  of  observation  multiplied  over 
every  continent.  They  will  leave  to  their  successors  the 
patient  investigations  made  during  their  lives — happy  if 
correlation  and  comparison  of  their  results  lead  to  the 
discovery  of  some  of  the  fundamental  laws  which  pre- 
side over  the  movements  of  the  atmosphere. 

In  presence  of  the  necessity  of  consulting,  as  fre- 
quently as  possible,  and  at  an  increased  number  of 
meteorological  stations,  the  various  instruments  by  which 
the  atmosphere  is  questioned,  it  was  soon  observed 
that  there  would  be  a  very  great  advantage  in  substituting 
for  the  labour  of  man  that  of  machines. 


2/0  THE   APPLICATIONS   OF    PHOTOGRAPHY. 

How  can  we  conderrin  an  5bser\*er,  however  con- 
scientious he  may  be,  to  read  off  several  times  every 
hour  and  for  entire  days  together  the  degree  of  the 
thermometer,  the  height  of  the  barometer,  to  take  a  note 
of  the  movements  of  the  magnetic  needle  and  the  rota- 
tions of  the  weathercock  ?  But  it  is  of  importance  to 
the  progress  of  meteorology  that  these  daily  observa- 
tions be  executed  with  the  precision  which  ought  to 
characterise  every  truly  scientific  document. 

What  man  cannot  do  is  accomplished  by  a  machine. 
To  obtain  this  ingenious  mechanism  capable  of  leaving 
on  paper  traces  of  the  movement  of  the  mercury  in  the 
barometer  and  the  thermometer  at  every  hour  of  the 
day  and  of  the  night,  of  indicating  the  slightest  disturb- 
ance which  may  occur  in  the  most  delicate  parts  of 
the  most  exact  instruments,  recourse  has  been  had 
to  the  valuable  aid  of  photography.  The  art  has 
been  applied  to  those  meteorological  instruments 
which  write  down  their  own  variations  at  every  moment, 
and  which  are  called  self-registering. 

The  idea  of  employing  for  the  study  of  meteoro- 
logical phenomena  apparatus  so  arranged  that  they  may 
themselves  mark  the  traces  of  the  influences  to  which 
they  are  subjected  is  not  new.  It  goes  as  far  back  as 
Magellan,  who,  in  1782,  had   constructed  thermometers 


PHOTOGRAPHIC  REGISTERING  INSTRUMENTS.      27 1 

and  barometers  which  registered  all  the  changes  caused 
by  the  variations  of  the  state  of  the  atmosphere. 

Registration  by  photography,  such  as  is  now  accom- 
plished in  a  great  number  of  observatories,  offers  the 
advantage  of  doing  away  with  the  complicated  mechan- 
ism which  every  other  method  required,  whether  me- 
chanical or  by  electro-magnetism.  This  mode  of 
registering  is  chiefly  utilised  for  the  variations  of  the 
barometer  and  the  thermometer,  and  the  oscillations  of 
the  magnetic  needle. 

It  is  well  known  that  at  the  upper  surface  of  the 
column  of  mercury  in  the  barometer  there  is  an 
empty  space  known  as  the  Torricellian  Vacuum.  If  a 
light  be  placed — that  of  gas  or  of  a  petroleum  lamp  for 
example — before  the  barometer  and  a  convex  lens  between 
them  to  converge  the  rays  of  light  on  the  upper  part  of 
the  tube  of  the  barometer,  an  image  of  the  lighted 
space  immediately  above  the  mercury  would  be  thrown 
upon  a  piece  of  sensitised  paper  placed  behind  it,  and 
this  image  would  vary  at  each  instant  with  the  varia- 
tions of  the  level  of  the  mercury  of  the  barometer. 

The  registering  thermometer  or  thermograph  is 
arranged  almost  in  the  same  manner,  only  it  is  necessary 
that  the  lamp  should  be  placed  at  some  distance  from 
the  apparatus  in  order  that  the  heat  emitted  by  it  may 


272  THE  APPLICATIONS  OF   PHOTOGRAPHY. 

not  act  upon  the  instrument ;  besides  this  the  light  does 
not  pass  through  the  empty  space  above  the  mercury, 
but  through  a  small  bubble  of  air  which  has  been  pre- 
viously introduced  into  the  thin  mercurial  column.  The 
light  thus  transmitted  produces  a  mark  like  a  point  on 
the  paper. 

In  these  instruments  the  sensitised  paper  is  stretched 
on  a  drum  which  regularly  revolves  by  means  of  clock- 
work, and  the  traces  of  the  variations  of  the  height  of 
the  mercury  in  the  barometer  and  the  thermometer  are 
found  marked  by  a  continuous  line,  when  the  paper  is 
withdrawn  and  submitted  to  the  operations  necessary  to 
fix  the  image. 

The  arrangement  of  the  mechanism  varies  according 
to  the  mode  of  registering  applied  to  different  instru- 
ments. In  order  to  adapt  photography  to  the  registra- 
tion of  the  variations  of  the  barometer,  Mr.  Ronalds, 
and  afterwards  Mr.  Salleron,  have  adopted  the  ingenious 
arrangements  which  we  shall  describe. 

This  self-registering  barometer  has  been  called  the 
photographic  barometrograph. 

An  ordinary  cistern  barometer  is  suspended  ver- 
tically by  an  iron  collar.  Before  this  instrument  is  a 
convex  lens  which  concentrates  the  light  of  an  argand 
lamp  or  a  jet  of  gas  on  its  upper  part.     The  upper  part 


PHOTOGRAPHIC   REGISTERING  INSTRUMENTS.      273 

of  the  tube  of  the  barometer  is  provided  with  a 
transparent  scale  of  glass  divided  into  fiftieths  of  an 
inch. 

The  luminous  ray  passes  through  this  scale  and 
above  the  surface  of  the  mercurial  column,  and  then 
through  an  achromatic  object-glass,  projecting  on  to  a 
sheet  of  sensitised  paper  the  image  of  the  graduated 
scale,  and  also  of  the  movable  surface  of  the  mercury. 

The  photographic  paper  is  fixed  to  a  frame  which 
moves  upon  a  carrier  in  a  plane  at  right  angles  to  the 
axis  of  the  object-glass.  Clockwork  is  applied  to  the 
frame  so  that  it  moves  its  own  length  in  twenty-four 
hours. 

It  results  from  the  whole  of  these  arrangements,  says 
M.  Pouriau,  to  whom  we  owe  an  excellent  work  on  self- 
registering  instruments,  that  the  light  thrown  on  the 
tube  of  the  barometer  is  arrested  by  the  mercurial 
column  forming  a  screen  the  image  of  which,  pass- 
ing through  a  lens,  falls  upon  the  sensitised  paper. 
The  representation  of  the  convex  or  concave  surface 
of  the  mercury,  and  the  divisions  of  the  scale  as  marked 
upon  the  tube  of  the  barometer,  are  at  the  same  time 
thrown  upon  the  sheet  of  paper  which  receives  their 
images  through  the  opening  admitting  the  rays  of  light 
from  the  lamp.     This  sheet  of  paper  fixed  to  the  carrier 

T 


274  THE  APPLICATIONS   OF    PHOTOGRAPHY. 

partakes  of  its  movement,  and  from  this  it  follows  that 
each  part  of  it  comes  in  succession  before  the  opening 
and  is  impressed  with  the  image. 

At  the  close  of  each  day  the  sheet  of  paper  is  taken 
out  of  the  frame ;  the  impression  is  then  fixed  by  the 
ordinary  photographic  process  ;  the  part  affected  by  the 
luminous  rays  forms  an  undulating  line  drawn  by  the 
upper  surface  of  the  mercurial  column,  the  height  of 
which  is  easily  measured  by  the  divisions  of  the  scale 
printed  upon  it  at  the  same  time. 

After  the  impression  has  been  fixed  on  the  paper 
a  sheet  of  glass  is  applied  to  it  divided  by  lines  into 
twenty-four  equal  parts,  and  if  the  hour  is  known  at 
which  the  operation  commenced,  it  is  easy  to  determine 
with  the  most  perfect  exactness  the  hour  corresponding 
to  all  the  points  of  the  line. 

When  a  photographic  registering  thermometer  is 
required,  in  place  of  the  tube  of  the  barometer  of  which 
we  have  been  speaking,  a  thermometer  having  the 
divisions  of  the  scale  cut  upon  glass  is  used.  The 
upper  surface  of  the  mercury  and  the  divisions  of 
the  scale  are  again  photographed  at  the  same  time. 
The  thermometer  is  curved  in  such  a  manner  as  to 
allow  the  bulb  being  passed  through  an  opening  in  the 
wall    of  the  room,  and   thus  exposed  to  the  influence 


o      < 

a 


PHOTOGRAPHIC   REGISTERING  INSTRUMENTS.      275 

of  the   external   temperature  which    it   is  intended  to 
measure. 

M.  Salleron  has  recently  constructed,  for  the  Obser- 
vatory at  Kew,  a  very  fine  photographic  self-registering 
apparatus  for  the  variations  both  of  the  barometer  and 
the  thermometer  at  the  same  time ;  after  what  we 
have  just  said,  a  description  of  it  will  be  easily  under- 
stood. 

The  arrangements  of  this  apparatus  are  represented 
on  the  right  and  left  of  the  engraving,  fig,  62. 

The  mercurial  barometer  is  at  the  middle  of  the 
table,  its  upper  part  being  represented  at  I.  O  is  the 
object-glass  of  the  photographic  camera.  H  is  the  clock- 
work which  moves  the  slide  carrying  the  photographic 
paper  by  means  of  the  rod  P. 

This  magnificent  apparatus  leaves  far  behind  it  all 
previous  arrangements  ;  for  not  only  does  it  act  as  a 
barometrograph,  but  it  also  registers  the  temperature 
and  the  hygrometrical  variations. 

The  thermometrograph  is  shown  to  the  right  of  our 
engraving.  It  is  upon  a  different  plan  to  that  of 
which  we  have  just  spoken.  The  metallic  reservoir  of 
air,  a,  is  sunk  into  the  earth,  and  remains  at  a  constant 
temperature ;  it  is  hollow  and  communicates  by  a  tube 
with  one  of  the  branches  of  a  tube  which  is  filled  with 


2/6  THE   APPLICATIONS   OF    PHOTOGRAPHY. 

mercury,  and  rises  between  the  light  and  the  object- 
glass,  O.  The  other  branch  of  the  tube  is  in  connection 
with  a  second  reservoir  of  air,  b,  which  remains  in  the 
surrounding  atmosphere.  The  difference  of  the  tem- 
peratures of  the  two  reservoirs  of  air  is  shown  by  a 
movement  of  the  mercury  in  the  glass  tube,  the  light 
passes  over  the  surface  of  the  fluid  metal  and  impresses 
the  photographic  paper  after  passing  through  the  object- 
glass  O.  It  traces  upon  the  moving  photographic  paper 
an  undulating  line  which  represents  the  variations  of  the 
mercury  in  the  tube,  and  consequently  the  temperature 
of  the  air. 

Another  similar  arrangement,  a'  and  b\  acts  as  a 
registering  psychrometer  or  measurer  of  the  am.ount  of 
watery  vapour  in  the  atmosphere.  The  reservoir  of  air,  a! , 
is  sunk  in  the  earth,  the  other  reservoir,  b\  which  is  kept 
moist,  remains  exposed  to  the  atmosphere  ;  both  again 
communicate  by  means  of  a  tube  with  two  branches  of 
a  glass  tube  containing  mercury,  over  the  surface  of 
which  the  luminous  rays  pass. 

Photography  is  not  only  applied  to  the  registration 
of  the  variations  of  the  barometer  and  thermometer, 
it  may  also  be  made  use  of  to  register  the  declination  of 
the  magnetic  needle,  as  Dr.  Brooke  has  proved  by 
the  construction  of  an  apparatus  equally  ingenious  as 


Fig.  63 


[Page  277 


PHOTO-ELECTROGRAPHIC    IIjf.STRUMENT   AT   KEW  OBSERVATORY,   FOR  REGISTERING 
THE   STATE    AND    VARIATIONS    OF   THE   EUKCTRICITV   OF    THE    A'R. 


PHOTOGRAPHIC  REGISTERING  INSTRUMENTS.      277 

correct,  and  which  is  constantly  in  use  at  the  Observatory 
at  Greenwich. 

The  magnetic  needle  carries  at  its  extremity  a  very 
small  mirror  on  which  the  light  of  a  lamp  falls.  The  re- 
flected ray  is  thrown  upon  a  piece  of  sensitised  paper 
placed  in  a  camera,  and  it  there  traces  an  arc  greater  or 
less  in  proportion  to  its  distance  from  the  photographic 
paper.  If  the  magnetic  needle  makes  the  slightest  move- 
ment, the  mark  of  the  reflected  ray  changes  its  place 
upon  the  screen — it  follows  faithfully  the  motion  of  the 
needle,  and  does  not  fail  to  note  its  least  oscillation. 

The  sensitive  paper  is  not  fixed,  but  is  attached  to  a 
cylinder  which  performs  one  revolution  upon  its  axis  in 
twenty-four  hours.  At  each  moment  the  reflection  of 
the  mirror  is  traced  upon  the  photographic  sheet,  which 
at  the  end  of  the  day  is  developed  and  fixed  by  the  or- 
dinary processes. 

Thus,  there  is  obtained  a  continuous  line  which  in- 
dicates the  movements  of  the  luminous  ray  reflected  by 
the  mirror  attached  to  the  magnetic  needle,  and  which 
shows  its  slightest  motion  during  the  course  of  the 
twenty-four  hours. 

At  the  Observatory  at  Kew,  an  analogous  system  is 
made  use  of  to  register  the  variations  of  the  electrical 
condition  of  the  atmosphere.     The  photo- electrograph 


2/8 


THE   APPLICATIONS   OF   PHOTOGRAPHY. 


Fig.  64. 


(fig.  63)  consists  of  a  lightning  conductor  in  connection 
with  an  ordinary  electroscope,  the  gold  leaves  of  which, 
as  is  well  known,  are  separated  more  or  less  from  one 
another  according  to  the  greater  or  less  quantity  of  free 
electricity  in  the  air. 

The  leaves  of  gold  illuminated  by  a  lamp  as  seen  in 
our  engraving  intercept  the  light  and 
throw  the  shadows  on  the  sensitive 
paper,  which  has  a  regular  down- 
ward motion,  produced  by  clock- 
work. Thus  are  obtained  two  un- 
dulating lines  which  .approach  or 
separate  at  eveiy  hour  of  the  day, 
and  show  with  absolute  correctness 
the  electric  state  of  the  atmosphere 
at  every  moment  (fig.  64). 

It  is  to  Francis  Ronalds  that  the 
honour  of  having  invented  this  ad- 
mirable system  of  registering  be- 
longs ;  this  photo-electrograph,  as  we 
have    said,    is    used   at    Kew,    and 


"oN^T^BCAR^rE'rorTHK  marks     down    night    and    day,    and 

ELECTROGRAPH.  _  ^  ^1  1  •      1    i.        ^ 

from     year    to    year,   the    slightest 
changes  in  the  electrical  state  of  the  atmosphere. 


PHOTOGRAPHIC  REGISTERING  INSTRUMENTS.      279 

Photometry  is  another  branch  of  physical  science 
which  has  found  a  powerful  assistant  in  the  operations 
of  the  photographer. 

When  it  is  desired  to  measure  the  intensity  of  two 
sources  of  light,  they  are  made  both  to  shine  at  the 
same  time,  and  the  strength  of  the  lights  measured 
by  the  comparative  depth  of  their  shadows.  But 
how  can  such  a  measurement  be  accomplished  if 
the  two  lights  cannot  be  got  to  shine  at  the  same 
time  .'* 

Though  the  comparison  is  easy  between  the  light  of  a 
candle  and  that  of  a  lamp  which  may  both  be  made  to 
burn  at  the  same  time,  how  is  the  student  to  act  if  he 
would  measure  the  relative  power  of  the  light  of  the 
sun  and  that  of  the  stars  oi  of  the  moon  }  The*  only 
means  of  solving  a  problem  so  delicate  is  by  photo- 
graphy. 

If  a  piece  of  sensitised  paper  be  exposed  to  the  in- 
fluence of  the  image  formed  at  the  focus  of  a  lens  by 
any  source  of  light,  will  not  the  amount  of  alteration 
produced  on  the  sensitive  surface  serve  to  measure  the 
intensity   of  the    light    emitted  .-* '       The  traces  of  the 

*  '  Intensity  of  light '  is  a  relative  phrase  which  may  refer  indefinitely, 
either  to  the  illuminating  power  or  to  the  photogenically  actinic  power 
of  rays  of  light.     Photography  supplies  an  accurate  test  for  the  illuminating 


28o  THE   APPLICATIONS   OF   PHOTOGRAPHY. 

luminous  source  are  no  longer  fugitive  like  the  shadows 
thrown  on  the  scale  of  the  ordinary  photo-meter ;  it  is 
durable  and  permanent,  and  can  be  compared  with 
that  produced  by  another  light  shining  at  a  different 
time. 

Photographic  photometry  has  enabled  science  to  com- 
pare the  luminous  intensity  of  the  solar  rays  with  that  of 
the  moon.  The  orb  of  day  gives  a  light  three  hundred 
times  greater  than  that  of  the  orb  of  night.  Thanks  to 
these  processes  physical  science  has  been  enabled  to 
trace  out  a  new  course  in  domains  considered  inac- 
cessible before  the  advent  of  photography. 

Herschel  and  Edmund  Becquerel  have  been  able  to 
study  effectually  the  peculiarities  of  the  solar  rays  at 
different  hours  of  the  day;  and  thanks  to  the  employment 
of  photographic  paper,  the  study  of  the  chemical  action 
of  light  to  which  these  distinguished  philosophers  have 


power  of  white  light  ;  but  when  a  ray  of  white  light  is  broken  up  and  the 
photographer  attempts  to  test  any  of  the  resulting  primary  or  secondary 
colours  of  the  spectrum,  his  observations  will  afford  him  no  guide  to  the 
illuminating  power  of  the  light.  Thus,  for  example,  a  luminous  homo- 
geneous yellow  light  will  have  no  more  effect  on  the  sensitive  plate  than 
if  he  had  attempted  to  photograph  an  object  in  pitchy  darkness;  whereas  the 
presence  of  blue  or  violet  rays,  however  feeble  or  imperceptible  to  the 
naked  eye,  may  at  once  be  detected  by  their  action  on  the  photographic 
plate. — Ed. 


PHOTOGRAPHIC  REGISTERING  INSTRUMENTS.      28 1 

devoted  their  attention  has  assumed  a  place  among  the 
most  interesting  chapters  of  modern  science. 

It  may  be  seen  by  the  brief  description  we  have 
given  of  the  admirable  instruments  which  are  employed 
at  some  of  our  observatories  how  valuable  registration 
by  means  of  photography  is,  since  it  enables  us  to  obtain 
exact  and  continuous  observations ;  but  these  instruments 
are  only  the  birth  of  yesterday — their  use  is  not  very 
extended,  and  they  will  certainly  be  soon  modified 
and  give  place  to  arrangements  still  more  complete  and 
ingenious. 

Besides  these  purposes,  photographic  registration 
may  be  applied  to  other  instruments  of  observation. 
For  example,  there  is  nothing  to  prevent  the  rain-gauge 
being  furnished  with  an  arrangement  which  would  show 
the  variations  of  its  level  by  means  of  a  tube  in  connec- 
tion with  the  receiving  vessel. 

The  future  will  prove  that  registration  is  the  funda- 
mental base  of  meteorological  science,  which  can  never 
establish  its  laws  unless  they  are  supported  by  continuous 
observation.  The  luminous  ray  will  write  in  silence  the 
movements  and  the  variations  of  all  the  apparatus  ;  the 
observer  will  only  have  to  come  once  each  day  to  con- 
sult the  sensitised  registers,  where  Nature  will,  so  to  say, 
have  marked  with  its  own  seal  the  periodical  or  inter- 


282  THE   APPLICATIONS   OF   PHOTOGRAPHY. 

mittent  changes  to  whose  mysterious  influences  it  is  un- 
ceasingly subject. 

It  must  not  be  supposed,  after  what  we  have  said,  that 
the  photographic  system  is  the  only  one  that  can  be  em- 
ployed for  the  registration  of  atmospherical  phenomena  : 
we  have  only  spoken  of  it  because  it  is  in  more  im- 
mediate connection  with  our  subject ;  and  besides,  it 
abounds,  as  will  have  been  seen,  in  new  and  curious 
appliances. 

It  may  be  necessary  to  add,  in  order  to  give  the 
reader  a  more  complete  idea  of  meteorological  registra- 
tion, that  in  addition  to  the  photographic  system,  science 
has  often  recourse  to  two  other  methods  ;  one  being  based 
upon  mechanical,  and  the  other  upon  electro-magnetic 
arrangements. 

The  first  consists  in  finding  in  the  variations  which 
the  instruments  experience,  the  power  required  to  put 
the  registering  pencils  in  motion  in  such  a  manner 
as  to  enable  them  to  leave  their  marks.  This  system 
is  the  most  ancient,  but  it  is  applied  with  diffi- 
culty in  consequence  of  the  small  amount  of  force 
which  is  at  command.  The  second,  as  its  name 
implies,  is  based  on  the  employment  of  dynamic 
electricity. 

The   employment   of  registration    by   photography 


PHOTOGRAPHIC   REGISTERING  INSTRUMENTS.      283 

offers,  in  a  great  number  of  cases,  very  decided  advan- 
tages ;  but  in  France  there  has  been  considerable  opposi- 
tion shown  to  this  system,  which  is  not  represented  in 
our  country  as  it  deserves. 

The  example  given  by  the  directors  of  the  Kew 
Observatory,  who  have  multiplied  photographic  regis- 
tering apparatus,  and  daily  use  with  success  and 
advantage  these  valuable  instruments,  should  cause 
our  philosophers  to  have  recourse  to  them  more  fre- 
quently. 

Photography  is  also  capable  of  furnishing  to  science 
means  of  measurement  quite  new  and  unexpected. 
The  'Journal  of  St.  Petersburg'  quite  recently  in- 
formed us  that  instantaneous  photography  has  been 
utilised  by  Lieutenant  Abnet  in  some  military  experi- 
ments, where  it  was  wished  to  calculate  the  projective 
force  obtained  from  explosive  substances  of  different 
natures  which  are  used  to  fill  the  torpedo  and  submarine 
bombs.  In  these  experiments  the  torpedo  was  buried 
in  the  sand  at  low  water,  and  exploded  by  an  electrical 
current  at  high  water.  By  means  of  photography  an 
observation  was  taken  of  the  height  of  the  column  of 
water  thrown  into  the  air,  and  then  at  low  water  again 
they  observed  the  extent  of  the  crater  formed  by  each 


284  THE  APPLICATIONS   OF   PHOTOGRAPHY. 

explosion  in  the  sand.  In  each  experiment  the  photo- 
graphic camera  did  its  duty  in  a  most  satisfactory- 
manner. 

Even  the  delicate  optical  phenomena  of  the  inter- 
ference and  the  diffraction  of  light  have  been  depicted 
by  photography.  Not  long  ago  Professor  Clinton 
showed  to  his  students  at  the  Clarendon  laboratory 
at  Oxford  a  fine  series  of  photographic  impressions  of 
the  phenomena  of  interference  and  diffraction. 

These  photographs  were  obtained  by  receiving  the 
rays  of  interference  on  prepared  plates  instead  of  the  or- 
dinary screen,  and  then  the  image  was  thrown  upon  a 
screen  in  the  lecture  room  by  means  of  the  oxyhydrogen 
light.  The  impression  produced  on  the  sensitive  plate  was 
sometimes  magnified  2,500  diameters.  The  subjects  thus 
photographed  and  thrown  upon  the  screen  comprised  the 
phenomena  of  interference  produced  by  Fresnel's  prism, 
the  rays  of  diffraction  by  thin  edges,  the  shadows  of  a 
straight  edge  and  of  an  angular  aperture,  the  rays  of  in- 
ternal interference  in  the  shadow  of  a  thin  wire  and  of  a 
needle  in  a  small  circular  disc  of  light,  and  the  pheno- 
mena presented  by  light  when  passing  through  a  small 
circular  hole.  The  professor  expressed  his  conviction 
that  it  was  the  first  time  photography  had  been  taken 
advantage  of  for  such  public  demonstrations. 


PHOTOGRAPHIC   REGISTERING   INSTRUMENTS.      285 


Photography  also  offers  great  advantages  to  the 
chemist  and  to  the  natural  philosopher  in  studying  the 
rays  of  the  spectrum. 

An  American,  Mr.  H.  Draper,  has  recently  applied 
photography  to  the  examination  of  the  violet  rays, 
and  also  to  the  space  beyond  them  ;  he  has  been 
able  to  reveal  some  new  rays  until  now  unknown.  He 
has  besides  shown  that  several  rays  which  were  consi- 
dered to  be  simple  are  in  reality  double  or  triple. 

But  the  English  scientist,  Mr.  Norman  Lockyer, 
has  gone  still  farther ;  he  has  made  use  of  the  photo- 
graphy of  the  rays  of  the  spectrum  to  create  the 
new  method  of  analysis,  as  ingenious  as  it  is  practical, 
now  made  use  of  at  the  London  Mint  to  examine  the 
alloys  of  gold  and  silver. 

The  alloy  of  gold  and  silver  is  placed  in  a  cavity 
made  in  the  lower  piece  of  charcoal  of  an  electric  lamp 

(fig.  65). 

It  is  then  volatilised  when  the  Voltaic  current  is  put  in 
motion ;  the  luminous  pencil  of  rays  passes  through  an 
opening,  O,  which  is  seen  enlarged  at  o',  and  the  rays 
from  the  gold  and  silver  thrown  upon  a  plate  in  a 
camera  are  photographed  directly  as  indicated  in  our  en- 
graving. The  photographs  obtained,  compared  with 
those  previously  produced  by  rays  of  light  from  alloys  of 


286         THE  APPLICATIONS  OF   PHOTOGRAPHY. 

known  composition,  serve  to  determine  the  proportion  of 
gold  and  silver  combined  in  the  alloy  examined,  it  being 
well  known  that  the  breadth  and  length  of  the  image 
varies  in  proportion  to  the  number  of  substances 
entering  into  the  composition  of  the  alloy. 


28/ 


CHAPTER   IX. 

THE   STEREOSCOPE. 

A  FEW  WORDS  ON  STEREOSCOPIC  VISION — MEANS  OF  MAKING  PHOTO- 
GRAPHIC PRINTS  APPEAR  IN  RELIEF— WHEATSTONE'S  STEREOSCOPE 
—  MONOSTEREOSCOPE — HOW  STEREOSCOPIC  PHOTOGRAPHS  ARE 
PRODUCED. 

Our  intention  is  not  to  describe  the  stereoscope  here  in 
its  relation  to  optics ;  we  shall  merely  refer  to  it  as  con- 
nected with  photography. 

We  consider  it  right,  however,  to  give  some  short 
account  of  an  instrument  which  enables  us  to  see  a 
design  drawn  upon  a  flat  surface  appear  as  if  it  were  in 
relief. 

Our  eyes  show  us  objects  as  they  are  in  relief ;  they 
are  not  seen  by  us  as  if  traced  on  a  plane  surface,  they 
appear  solid  and  raised. 

The  study  of  the  laws  of  vision  shows  that  this  effect 
is  produced  by  two  images  seen  simultaneously,  one 
being  perceived  by  each  eye.  Here  is  an  experiment 
easily  made  which  will  show  this  at  once.  Place  before 
your  eyes  a  book  in  a  vertical  position  so  that  the  back 


288  THE   APPLICATIONS   OF    PHOTOGRAPHY. 

of  it  is  visible.  Shut  the  right  eye  and  open  the  left, 
and  you  will  see  the  left  side  of  the  book.  After  this, 
if  you  shut  the  left  eye  and  open  the  right,  then  the 
back  and  the  right  side  of  the  book  only  will  be  seen. 
In  order  to  make  the  experiment  more  striking,  if  a 
sheet  of  white  paper  be  stuck  on  one  side  of  a  book 
bound  in  red  or  any  other  colour,  the  white  or  the  coloured 
side  will  be  seen  alternately,  according  as  the  right  or 
left  eye  is  opened  ;  when  both  eyes  are  open,  both  sides 
will  be  seen.  The  experiment  may,  in  the  same  way, 
be  made  with  a  cube  or  a  quadrangular  pyramid  (fig.  66). 
Both  the  right  and  left  faces  are  seen  when  both  eyes 
are  open,  and  according  as  the  right  or  the  left  eye  is 
shut  the  cube  or  the  pyramid  assumes  the  appearance  of 
our  figures  on  the  right  and  left.  Our  minds  by  the 
force  of  habit  combine  the  two  pictures,  and  this  gives 
the  impression  of  relief  or  of  being  raised  or  solid. 

To  make  use  of  a  stereoscope,  that  is  an  instrument 
which  gives  to  a  picture  on  a  flat  surface  the  appearance 
of  being  in  relief,  it  is  necessary  to  take  two  impressions 
of  the  picture  so  that  each  impression  represents  the 
object  to  each  eye  as  the  solid  object  itself  would. 

One  of  the  first  stereoscopes  given  to  the  public  was 
that  invented  by  Wheatstone.  This  instrument  is  con- 
tained in  a  rectangular  box.  Two  views  of  the  same  object, 


THE  STEREOSCOPE. 


289 


represented  according  to  the  principles  of  stereoscopic 
vision,  are  placed  in  grooved  slides,  one  at  each  side  of 
the  box  ;*  two  small  mirrors  are  fixed  at  right  angles  to 
one  another  in  the  centre  of  the  box  ;  the  eyes  of  the 

Fij?.  66. 


®  : 


observer,  being  situated  a  little  in  front  of  the  mirrors, 
will  see  the  pictures  at  the  sides  reflected  from  them, 
and  when  the  eyes  are  at  the  proper  distance,    the  two 

'  It  is  not  generally  known  that  in  taking  a  photo-micrograph  of 
minute  invisible  crystals,  or  of  any  microscopic  preparation  standing  out 
in  relief,  in  order  to  obtain  a  perfect  stereoscopic  photograph  of  the  object, 
neither  the  camera  nor  the  preparation  need  be  moved.  The  stereoscopic 
relief  may  be  obtained  by  first  taking  a  picture  with  the  light  on  one  side, 
and  then  taking  a  second  picture  with  the  light  on  the  other  side  of  the 
object. — Ed. 

U 


290 


THE  APPUCATIONS  OF   PHOTOGRAPHY. 


pictures  as  reflected   and  viewed  through  lenses  will  ap- 
pear as  one,  and  in  relief. 

Brewster's  stereoscope  (fig.  67),  and  that  of  Heimholtz 
(fig.  68),  are  on  somewhat  different  principles,  and  are 
considered  to  be  improvements  on  Wheatstone's.    Every 


BREWSTER  S   STEREOSCOPE. 


one  has  looked  at  photographs  through  such  instruments  ; 
their  management  is  too  simple  and  their  use  too  com- 
mon to  require  us  to  spend  any  time  in  describing  them. 
The  stereoscope  was  invented  at  about  the  same 
time  as  the  daguerreotype.  At  first  it  was  used  for  the 
purpose  of  viewing  pictures  drawn  by  the  hand,  but  on 


TIIK   STEREOSCOPE. 


291 


the  discovery  of  photography  the  two  new  arts  lent  each 
other  mutual  support  ;  they  became  so  intimately  con- 


HEIMHOLTZS    STEREOSCOPE. 


nected  that  now  the  stereoscope  and  the   photograph 
appear  to  be  almost  two  parts  of  the  same  instrument. 


u  2 


292  THE   APPLICATIONS   OF    PHOTOGRAPHY. 


In  1858  an  able  operator,  M.  Claudet,  invented  a 
very  curious  kind  of  stereoscope  which  can  be  seen  by 
several  people  at  the  same  time.  This  instrument  con- 
sists of  a  dark  screen  the  centre  of  which  has  been  cut 
out  and  the  space  occupied  by  a  piece  of  ground  glass  ; 
by   means  of  two   magic  lanterns,   two    images   of   the 

Fig.  69. 


MONO-STEREOSCOPIC    PRINT. 


same  object  are  thrown  upon  this,  and  are  so  combined 
as  to  give  the  impression  of  the  picture  being  in  relief, 
without  the  necessity  of  viewing  it  through  any  optical 
instrument  (fig.  69).^ 

'  This  method  of  combining  stereoscopic  pictures  is  not  so  successful 
as  to  command  extensive  application.  — Ed. 


THE   STEREOSCOPE. 


293 


The  facility  of  procuring  by  means  of  photography 
views  so  delicately  printed  by  Nature  herself  has 
singularly   contributed  to   the  perfecting  of  the  stereo- 


Fig.  70. 


FEVRIERS    PILLAR    STEREOSCOPE, 


scope,  which   is   now  manufactured  with  admirable  cor- 
rectness. 

After  Brewster's  stereoscope,  the   Pillar  Stereoscope 
(fig.  70),  invented  by  M.  Fevrier,  gives  to  photographs 


294  THE   APPLICATIONS   OF    PHOTOGRAPHY. 


such  an  appearance  of  relief,  and  so  enlarges  them,  that 
nothing  can  better  represent  natural  objects. 

In  this  apparatus,  with  the  eyes  fixed  upon  the  lenses, 
by  turning  a  small  button  causing  the  rotation  of  an 
axis,  around  which  the  stereoscopic  photographs  are 
arranged,  Switzerland,  the  Pyrenees,  China,  Japan, 
come  one  after  the  other  under  the  view  of  the  observer, 
who  can  admire,  without  stirring  from  his  chair,  distant 
places,  even  those  most  inaccessible  to  the  traveller. 

We  now  come  to  the  processes  employed  in  producing 
photographic  impressions  suitable  for  being  viewed 
through  the  lenses  of  the  stereoscope. 

The  photographic  picture  should  be  double,  that  is 
to  say,  it  is  necessary  to  take  two  views  of  the  same 
subject  ;  these  two  views  ought  to  be  identical  in  their 
central  parts,  but  differ  a  little  at  their  sides.  To  attain 
this  result  a  first  view  is  taken  of  the  object  by  placing 
the  photographic  camera  towards  the  right,  and  then  a 
second  view  is  taken  after  moving  it  a  little  to  the  left. 

To  give  greater  correctness  to  the  impressions  two 
views  are  generally  taken  at  the  same  time  by  two  dis- 
tinct cameras,  having  lenses  of  uniform  focus,  fastened 
together  by  a  movable  slide  fixed  on  the  top  of  a 
tripod. 

If  it  be  wished  to  take  two  stereoscopic  pictures  of 


U'age  295 


APPARATUS    FOR   OBTAINING   THE   TWO   PROOFS   OF   THE 
STEREOSCOPE. 


THE   STEREOSCOPE.  295 

an  object,  such  as  a  picture  or  a  statue,  the  two  cameras 
are  placed  at  about  the  distance  of  ten  feet  from  the 
model,  and  are  separated  from  each  other  by  about  six 
inches.  Care  must  be  taken  before  introducing  the 
collodionised  glass  into  the  cameras  that  the  inclination 
of  the  two  images  in  the  foci  of  the  cameras  is  such 
as  will  produce  the  desired  effect.  For  this  purpose 
it  must  be  ascertained  that  the  point  of  the  object  which 
is  in  the  centre  of  the  ground  glass  of  the  camera  to  the 
right  be  also  exactly  in  the  centre  of  the  ground  glass 
of  that  to  the  left.  This  fundamental  observation  being 
once  made,  the  photographs  are  taken  in  the  ordinary 
manner.  The  apparatus  ready  for  use  is  represented  in 
figure  71.  Figure  73  gives  the  facsimile  of  a  stereo- 
scopic slide   formed  of  two  photographic  views  placed 

Fig.  72, 


PLATE   FOR    SUPPORTING    THE   CAMERA    WHEN    TAKING    STEREOSCOPIC   VIEW. 

beside  one   another  under  the  conditions   suitable    tor 
stereoscopic  vision. 

It  is  a  good  plan  to  print  the  positives  for  the  stereo- 
scope upon  glass  ;  the  transparency  of  the  glass  lights 


296  THE   APPLICATIONS   OF   PHOTOGRAPHY. 

up  the  picture  better  and  helps  to  give  it  relief  and 
solidity.* 

When  it  is  wished  to  take  stereoscopic  views  of  land- 
scapes, buildings,  or  of  distant  objects  in  general,  only  one 
view  is  taken  at  a  time  with  one  camera.  This  camera 
rests  upon  a  plate  on  which  it  moves  easily  from  right  to 
left  guided  by  two  squares  which  move  in  a  groove  as 
seen  in  fig.  'J2.  A  first  view  of  the  subject  is  taken  by 
placing  the  camera  at  the  right  side  of  the  plate,  care- 
fully observing  the  object  which  is  in  the  centre  of  the 
ground  glass  of  the  camera.  This  view  having  been 
taken,  the  camera  is  moved  to  the  left  of  the  plate  and 
carefully  adjusted  so  that  the  same  object  is  again  in 
the  centre  of  the  ground  glass,  though  the  lens  has 
changed  its  position  ;  a  second  view  is  then  taken.  The 
two  positions  occupied  by  the  camera  are  separated  by 
about  three  inches,  a  distance  which  nearly  corresponds 
with  that  of  the  pupils  of  the  human  eyes. 

'  The  position  of  the  two  pictures  taken  in  this  way  must  be  reversed 
when  printed  and  mounted  on  card.  — Ed. 


297 


CHAPTER  X. 

PHOTOGRAPHY   AND   ART. 

IS  PHOTOGRAPHY  ART  ?— ITS  USES  IN  RELATION  TO  PAINTING 
REPRODUCTION  OF  ENGRAVINGS  — VOYAGES  OF  DISCOVERY— PHO- 
TOGRAPHY BY  THE  MAGNESIUM  LIGHT— PHOTOGRAPHIC  PORTRAITS 
CONSIDERED  AS   HISTORICAL   DOCUMENTS. 

Painters  are  not  generally  carried  away  by  their  ad- 
miration of  photography;  its  physico-chemical  processes 
seem  incompatible  with  the  sentiments  which  animate 
them  ;  they  feel  repugnance  in  placing  collodion  beside 
a  palette  of  oil  colours.  Many,  indeed,  are  very  severe 
upon  the  art  of  Daguerre  ;  there  are  some  who  cannot 
hear  a  photographic  print  praised  without  feeling  much 
annoyed. 

Photography,  they  say,  composes  -nothing ;  it  only 
gives  a  copy,  a  mere  imitation,  brutal  in  its  truth.  It 
wants  sentiment,  no  flame  of  genius  gives  it  life.  It  is 
awkward,  it  gives  an  equal  value  to  important  parts  and 
to  accidental  details. 

If  it  takes  a  portrait  it  copies  its  model  unskilfully  ; 
it  represents  the  ornaments  of  a  dress  better  than  it  can 


298  THE   APPLICATIONS    OF    PHOTOGRAPHY. 

give  the  expression  of  a  face  ;  the  eye  of  the  sitter  is  not 
given  better  than  the  button  of  his  sleeves  ;  photography 
is  mere  mechanism,  it  is  not  art. 

To  produce  a  good  negative,  say  the  photographers, 
on  the  other  hand,  it  is  necessary  to  study  the  subject  as 
well  as  to  select  and  combine  the  effects  of  light ;  and 
this  needs  the  intervention  of  artistic  sentiment.  The 
first  negative  obtained,  says  a  distinguished  practitioner 
of  the  art,  the  work  is  only  sketched  out.  Light  is  an 
uncertain  instrument  which  is  never  under  complete  con- 
trol. It  is  necessary  that  the  photographer,  appreciating 
its  defects  and  its  merits,  should  palliate  the  one  and 
bring  out  the  other  more  prominently.  It  is  then,  adds 
our  apologist,  that  the  photographer  shows  himself  to  be 
an  artist  in  the  full  acceptation  of  the  word  ;  that  he 
causes  his  mind  and  his  genius,  if  he  have  genius,  to 
pass  into  the  print ;  that  he  gives  it  colour  and  that 
admirable  completeness,  as  well  as  those  effects  which 
impress  and  take  hold  of  the  mind  in  as  lively  a  manner 
when  admiring  certain  photographic  portraits  or  land- 
scapes as  when  in  presence  of  a  canvas  of  Ruysdael  or 
of  Titian. 

In  a  series  of  photographs,  says  an  eminent  scientific 
writer,  we  meet  by  turns  a  Van  Dyk  and  a  Delaroche, 
a  Reynolds   and    a   Turner,    a  Titian  and  a   Scheffer,  a 


PHOTOGRAPHY  AND  ART.  299 


Ruysdael    and    a    Corot,    a    Claude    Lorraine    and    a 
Marilhat. 

These  views  are  evidently  exaggerated  on  both 
sides.  Let  us  try  and  give  a  just  and  reasonable  opinion, 
avoiding  the  two  rocks  of  systematic  disparagement  and 
of  too  enthusiastic  admiration. 

Certainly  photography  has  serious  disadvantages. 
The  instrument  which  acts  has  not  the  powers  of  the  artis- 
tic hand,  which  is  guided  by  the  love  of  the  beautiful  and 
just  impressions  of  the  effects  of  nature.  It  often  injures 
the  linear  as  well  as  the  aerial  perspective  ;  the  process  of 
developing  the  image  not  unfrequently  reproduces  the 
distances  as  distinctly  as  the  foregrounds  ;  while  the 
shadows  in  some  photographs  form  dark  blots,  flat  and 
heavy  tones,  which  deprive  the  picture  of  all  grace  and 
"harmony.  Especially  is  this  the  case  if  the  instrument 
is  guided  by  an  inexperienced  hand. 

But  it  cannot  be  denied  that  the  photographic  ap- 
paratus, if  managed  by  the  hand  of  an  operator  having 
at  the  same  time  the  skill  of  a  proficient  and  the  taste 
of  the  painter,  produces  pictures  marked  with  the  seal  of 
art. 

We  see  every  day  issue  from  the  studios  of  the 
masters  of  the  art  a  great  number  of  admirable  photo- 
graphs :    they  have  colour,  relief,  delicacy,  and    truth  ; 


300  THE   APPLICATIONS   OF   PHOTOGRAPHY 


some  of  them  even  can  rival  the  most  beautiful  sepia 
drawings,  or  the  finest  miniatures.  If,  on  the  other  hand, 
there  are  bad  photographs,  it  must  be  admitted  that 
some  shocking  bad  pictures  exist. 

We  shall  not  enter  further  into  this  order  of  ideas 
and  discussions.  It  is  dangerous,  in  our  opinion,  to  wish 
to  establish  a  parallel  between  painting  and  photo- 
graphy, which  differ  essentially  in  their  processes  and 
mode  of  production.  At  the  same  time  it  appears  to  us 
to  be  exceedingly  unjust  to  deny  to  photography  the 
rank  of  one  of  the  fine  arts. 

It  constitutes,  doubtless,  a  true  and  a  great  art ;  but 
we  shall  quit  this  slippe^ry  ground  for  the  purpose  of 
broaching  a  much  more  interesting  question,  that  of  the 
services  which  photography  is  capable  of  rendering  to 
all  artists  -to  the  painter,  to  the  sculptor,  to  the  archi- 
tect 

The  illustrious  Paul  Delaroche,  soon  after  the  in- 
vention of  the  daguerreotype,  did  not  fear  to  say,  in  pre- 
sence of  the  members  of  the  Academy  of  Science,  the 
daguerreotype  carries  to  such  perfection  certain  essential 
points  of  art  that  it  must  become  an  object  of  study 
and  observation  to  the  greatest  painters.  Paul  Dela- 
roche spoke  the  truth.  A  collection  of  photographs  is 
indeed  an  inexhaustible  source  of  useful  information  for 


PHOTOGRAPHY  AND  ART.  301 


the  artist.  It  is  certain  that  no  painter  at  this  day, 
whatever  may  be  his  talent,  will  attempt  to  paint  a  por- 
trait without  having  good  photographic  likenesses  of  his 
sitter.  It  is  also  evident  that  a  landscape  painter  cannot 
be  too  well  acquainted  with  those  admirable  studies  of 
nature  which  true  artists  have  placed  upon  the  collodion- 
ised  glass.  The  student  will  also  find  valuable  examples 
in  those  fine  photographs  which  reproduce  the  magni- 
ficent cartoons  of  the  Louvre — unique  sketches,  the 
produce  of  the  magic  crayon  of  Raphael,  or  the 
pencil  of  Michael  Angelo.  No  one  would  be  bold 
enough  to  attempt  to  reproduce  the  designs  of  these 
great  masters  by  the  burin  of  the  engraver,  or  by  the 
pen  of  the  lithographer.  Photography  performs  the 
miracle  of  multiplying  to  infin'ty  an  etching  of  Correggio 
or  of  Titian. 

Again,  what  resources  in  the  hands  of  an  architect, 
or  an  archaeologist,  are  the  views  of  buildings  in  distant 
countries  !  The  marvels  of  Athens  and  of  Rome,  the 
inimitable  richness  of  the  monuments  of  India,  the  bold 
architecture  of  Egyptian  temples,  can  be  kept  in  his 
portfolio,  not  modified  and  disfigured  by  an  untrust- 
worthy pencil,  but  such  as  they  are  in  reality  with  their 
beauties,  their  imperfections,  and  the  marks  of  destruc- 
tion which  time  has  engraved  upon  them.    Photographic 


302  THE   APPLICATIONS   OF    PHOTOGRAPHY. 


prints  are  mirrors  from  which  are  reflected  the  banks  of 
the  Nile  and  of  the  Indus — the  buildings  and  the  land- 
scapes of  all  the  countries  through  which  the  camera  has 
passed. 

The  explorer  furnished  with  his  photographic  ap- 
paratus, which  is  now  constructed  in  such  a  manner  that 
it  can  be  used  with  ease  in  any  part  of  the  world  (fig.  74), 
brings  back  with  him  from  his  travels  documents  in- 
valuable, because  no  one  can  deny  their  accuracy.  A 
photograph  represents  an  object  just  as  it  is — the  land- 
scape as  nature  has  formed  it — the  building  as  it  has 
been  seen,  a  broken  column,  a  mark  upon  a  stone.  No- 
thing is  deficient  in  the  print.  A  painting  or  a  water- 
colour  can  never  have  such  rigorous  precision.  The 
artist  is  often  tempted  to  omit  some  object  which  appears 
to  injure  the  efi"ect  of  the  whole,  or  to  add  some  orna- 
ment to  his  work. 

Finally,  in  certain  cases,  photography  is  able  to  repro- 
duce by  the  aid  of  artificial  light  the  representation  of 
masterpieces  of  art  or  of  natural  beauties  which  may  be 
buried  in  darkness.  In  a  great  number  of  subterranean 
chambers,  hollowed  out  under  the  ancient  temples  of 
Egypt,  the  walls  are  covered  with  paintings  and  hiero- 
glyphs which  the  savant  cannot  study  with  advantage 
during  a  short  visit.  The  photographer,  by  means  of  the 
magnesium  light,  takes  the  exact  transcript  of  these  in- 


PHOTOGRAPHY   AND   ART. 


303 


scriptions,  or  of  these  figures  ;  he  puts  in  the  hands  of  the 
archaeologist  a  faithful  copy  on  which  he  can  study,  by  the 
aid  of  a  magnifying  glass,  the  most  minute  details.  The 
mode  of  operating  most  frequently  practised  in  Egypt  is 


Fie:.  7= 


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fe>  .-.. 

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a:«C 

•"■■■'^ffi^  ^ 

--.'^m,-  k' 

a^^ 

^-^^ 

W       . 

m 

c    --^^ 

.  -^f  ^ ,/ -    • 

^  "^c* 

■*  f     '  ^ 

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Sr?  r>^^^^ 

^^^^ 

^^^^                                 r^:v 

rHOTOGRAl'HY    BY    THE   MAGNESIUM    LIGHT    IN    THK   CATACOMBS. 


identical  with  that  employed  in  taking  photographic  views 
of  certain  curious  parts  of  the  catacombs  of  Paris% 
(Fig.  75.) 

The  applications  of  photography  to  art  are  in- 
numerable, and  the  future  will  produce  many  results  of 
the  extent  of  which  we  cannot  now  give,  an  idea. 


304  THE  APPLICATIONS   OF   PHOTOGRAPHY 


The  carbon  process  of  photographic  printing,  only 
recently  discovered,  will  soon  produce,  if  it  has  not 
already  succeeded  in  producing,  unchangeable  prints  as 
durable  as  the  impressions  of  typography  ;  it  will  thus 
perpetuate  in  history  the  appearance  of  the  great  men  who 
have  played  their  part  in  the  cjianges  of  modern  society. 
What  incomparable  value  would  now  be  attached  to 
photographs  of  the  great  writers  of  the  age  of  Louis 
XIV.,  or  of  the  philosophers  of  the  eighteenth  century! 
What  profound  emotion  would  not  one  feel  in  contem- 
plating the  truthful  images  of  the  men  of  genius  who 
have  enlightened  humanity ! 

Our  descendants  will  assuredly  enjoy  such  surprises 
and  many  more,  which  the  most  clear-sighted  cannot 
foresee. 

All  that  we  can  affirm  is,  that  if  the  uses  of  photo- 
graphy are  now  almost  innumerable,  they  will  certainly 
still  go  on  increasing  to  an  unknown  extent.  How- 
ever marvellous  the  results  already  obtained  may  be, 
they  will  be  improved  so  as  to  reach  such  a  summit  of 
perfection  as  our  mental  eye  cannot  perceive  through 
the  dense  mist  which  veils  from  us  the  image  of 
the  future.  We  have  seen  the  efforts  made  by  Becquerel 
and  Niepce  de  Saint-Victor  to  obtain  photographs  with 
the  colours  of  nature.     The  problem  of  coloured  photo- 


PHOTOGRAPHY  AND  ART.  305 

graphy  is  not  insoluble.  It  will  be  solved  one  day. 
Then  the  art  will  march  along  a  new  course  wonderfully 
fruitful  in  such  results. 

It  is  often  imprudent,  and  even  undesirable,  to  attempt 
to  look  too  closely  into  the  future,  but  in  some  cases  it  is 
possible  to  do  so  without  exceeding  too  much  the  limits 
of  reason.  In  such  cases  it  is  necessary  to  rest  upon 
facts,  and  not  give  too  much  play  to  the  imagination. 
We  have  studied  the  past  of  photography  ;  we  have  ad- 
mired the  marvels  we  owe  to  it  in  the  present ;  will  the 
reader  pardon  us  if  we  now  endeavour  to  dive  a  little 
into  the  future  t 


306  THE   APPLICATIONS   OF   PHOTOGRAPHY. 


CHAPTER   XL 

THE   FUTURE   OF   PHOTOGRAPHY. 

LAND-SURVEYING — THE  ART  OF  WAR— WORKS  OF  ART— CRIMINALS 
AND  JUDICIAL  PHOTOGRAPHY-  THE  MIRACLES  OF  INSTANTANEOUS 
PHOTOGRAPHY. 

If  we  would  fathom  the  depths  of  the  future  while  re- 
straining ourselves  at  the  same  time  within  the  limits  of 
common  sense,  we  must  carefully  examine  the  ground 
over  which  we  would  extend  our  view.  We  shall  first 
examine  what  has  been  done  up  to  this  time  in  utilising 
photography  in  the  art  of  taking  plans,  and  then  we 
shall  be  able  to  perceive  the  resources  it  will  afford 
during  war. 

A  retired  military  surgeon,  M.  Auguste  Chevalier,  has 
already  considered  it  possible  to  combine  surveying  with 
photography.  He  places  a  camera  on  a  land-surveyor's 
stand,  fixing  it  upon  an  axis  so  that  it  can  be  turned 
round  in  any  direction.  By  directing  the  lens  of  the 
camera  to  the  different  points  of  the  horizon  pictures  of 
each  part  are  obtained,  the  whole  forming  a  complete 


THE  FUTURE  OF  PHOTOGRAPHY.       3O7 

panorama  which  must  be  absolutely  correct ;  from  this  a 
plan  or  map  of  the  country  can  be  drawn  by  means  of 
certain  operations,  the  details  of  which  are  too  technical 
for  us  to  enter  into. 

In  1859,  during  the  war  in  Italy,  some  military  en- 
gineer officers,  no  doubt  thinking  of  the  polemoscope 
reflecting  images  by  means  of  mirrors  (fig.  ^6),  a  kind  of 
forerunner  of  the  employment  of  the  camera,  made  use 
of  the  photographic  plate.  The  experiments  they  made 
allowed  them  to  form  some  idea  of  the  advantages  of 
this  new  branch  of  photography,  though  they  did  not 
thoroughly  master  it.  No  doubt  in  the  future,  the 
camera  will  supply  valuable  assistance  to  the  military  art. 

The  application  of  photography  to  taking  military 
plans  and  panoramic  views,  in  the  opinion  of  competent 
judges,  is  on  the  eve  of  being  completely  realised.  When 
this  new  application  is  perfected,  science  will  again  be 
distinguished  by  considerable  progress.  We  cannot 
over-estimate  the  great  services  the  camera  ought  to 
render  in  this  kind  of  work. 

No  longer  any  want  of  correctness  in  producing  the 
plan,  no  minute  calculation,  no  difficulty,  no  annoy- 
ance. The  picture  of  the  country  will  be  taken,  the  map 
will  be  completed,  without,  so  to  say,  giving  it  a  thought. 
In  time  of  war,  a  general  will  have  photographs  of  the 


308  THE  APPLICATIONS   OF   PHOTOGRAPHY. 

field  of  battle — of  the  fortresses  he  would  besiege,  and 
should  any  point  of  the  horizon  be  concealed  from  him, 
the  camera  thrown  into  the  car  of  a  balloon  held  captive 
by  a  cord,  and  thus  rising  above  woods  and  hills,  will 
take  a  faithful  impression  of  all  within  its  view. 

Narrators  of  fairy  tales  and  other  extravagant  stories 
have  often  put  into  the  hands  of  their  heroes  magic  mir- 
rors, wonderful  talismans,  which  suddenly  reflect  the 
images  of  distant  objects.  Photography  realises  the  con- 
ceptions of  the  imagination  of  the  poet.  We  remember 
being  present  at  a  singular  scene,  which  we  shall  en- 
deavour to  describe. 

One  of  our  friends,  a  military  engineer,  engaged  in 
superintending  some  railway  works,  was  addressing  some 
words  of  blame  to  the  contractor  who  was  employed  in 
building  a  bridge.  He  complained  of  certain  faults  of 
construction,  and  especially  at  the  slow  progress  of  the 
work. 

'  But  I  beg  your  pardon,'  replied  the  contractor. 
*  Are  you  quite  sure  your  information  is  correct,  for  you 
have  not  personally  visited  the  works  } ' 

'  I  have  not  stirred  from  home,  it  is  true,'  replied  the 
engineer;  'but  here  is  a  mirror  which  is  sent  to  me 
regularly,  and  which  tells  me  every  week  what  quantity 
of  stones  you  have  collected,  what  number  of  bars  of 


THE   FUTURE   OF   PHOTOGRAPHY.  309 


iron  you  have  got  together.'     He  then  took  from  his 
drawer  some  photographs. 

*  I  employ  a  photographer,'  he  continued, '  who  sends 
me  every  morning  a  picture  of  your  work  taken  on 
the  spot.  Here  is  the  complete  series.  The  moving 
crane,  which  a  fortnight  ago  was  three  yards  from  the 
second  pile  and  which  advanced  five  yards  the  preceding 
week,  has  moved  very  slowly  for  the  last  eight  days.  It 
is  necessary,  I  tell  you,  to  be  more  active.  All  that  you 
do  there,  I  see  here  ;  the  photographs  which  are  sent  to 
me  give  me  even  the  appearance  of  your  workmen,  and 
if  one  of  them  has  been  idling  while  the  picture  was 
being  taken,  I  can  take  him  to  task  from  my  office  here.' 

I  listened  to  this  singular  conversation,  and  I  said  to 
myself,  that  the  future  would  work  out  more  perfectly 
this  system  already  made  use  of  The  day  may  perhaps 
come  when  the  negative  will  be  taken  at  a  distance  by 
means  of  the  electric  wire  ;  and  if  some  reader  exclaims. 
Impossible  !  I  shall  refer  him  to  certain  telegraphic  sys- 
tems lately  discovered,  which  allow  us  to  anticipate  this 
new  miracle.^ 

Not   less   wonderful    is    the   arrest  of    criminals  by 

'  I  believe  that  there  is  nothing  Utopian  in  the  notion  that,  ere  long, 
means  will  be  discovered  of  telegraphing  a  photograph  from  one  end  of 
the  earth  to  the  other  ;  a  most  desirable  consummation  for  the  Metropolitan 
Police,  and  for  the  •  Illustrated  London  News  '  and  *  Graphic' — Ed. 


3IO  THE   APPLICATIONS   OF    PHOTOGRAPHY. 

means  of  their  photographs.  Here  are  some  accounts  of 
what  has  been. done  in  England,  of  a  nature  to  show  us 
the  resources  of  judicial  photography. 

It  appears  from  a  report  on  photographing  criminals 
in  London  that  from  the  20th  November  1871,  to  the 
31st  December  1872,  375  arrests  took  place  in  England 
in  consequence  of  the  identity  of  criminals  having  been 
proved  by  means  of  their  photographic  portraits.  Dur- 
ing this  time  there  had  been  received  from  county  and 
borough  prisons  at  the  Habitual  Criminals  Office  30,463 
portraits  of  criminals.  This  shows  that  the  practice  of 
taking  the  portraits  of  malefactors  by  means  of  photo- 
graphy is  useful,  and  at  the  same  time  we  may  mention 
it  does  not  cost  much,  since  the  portraits  of  all  the  pri- 
soners of  the  1 1 5  prisons  of  England  and  Wales,  from  the 
time  that  the  Act  of  1870  came  into  operation  to  the  3  ist 
December  1873,  only  cost  2,948/.  18.$'.  3</.  Perhaps  it 
might  be  desired,  in  order  to  make  the  services  it  ren- 
ders more  practical,  that  the  criminal  portrait  gallery 
should  be  open  to  the  public.  It  would  thus  be  possible 
to  make  the  arrest  of  malefactors,  upon  whom  the  police 
are  unable  to  lay  their  hands,  more  easy.  It  would  be 
the  same  with  dead  bodies  which  had  not  been  claimed 
by  anyone.     We  do  not  doubt  that  means  would  thus  be 


THE  FUTURE  OF  PHOTOGRAPHY.       311 

found  for  the  arrest  of  murderers,  whose  names,  as  well 
as  those  of  their  victims,  remain  unknown. 

It  is  again  from  the  foreigner,  and  this  time  from  the 
United  States,  that  we  take  some  accounts,  still  more 
singular  perhaps,  of  the  uses  to  which  the  art  of  Daguerre 
may  be  put. 

An  eye-witness  from  the  other  side  of  the  Atlantic, 
who  was  present  at  some  of  the  riotous  scenes  of  the 
last  elections,  assured  us  that  an  American  photo- 
grapher had  succeeded  in  taking  an  instantaneous  picture 
of  a  public  meeting  in  the  open  air.  He  had  suddenly 
fixed  in  the  focus  of  the  camera  the  orator  who  was 
gesticulating  from  the  top  of  a  temporary  husting's,  the 
group  of  listeners  who  were  raising  and  waving  their 
arms,  some  showing  marks  of  approbation  and  approval, 
others  with  signs  of  impatience  and  anger.  This  photo- 
graph was  immediately  taken  to  his  studio,  for  the 
purpose  of  converting  the  negative  into  a  plate  to  be 
printed  from  by  the  heliographic  process.  If  he  had  suc- 
ceeded, that  very  evening  there  might  have  been  distri- 
buted 100,000  copies  of  the  photograph,  printed  in  an 
ordinary  printing  press.  He  failed,  but  others  will 
accomplish  this  wonder  of  producing  upon  collodion 
such  animated  scenes,  in  depicting  in  a  permanent 
form    man   in    action,    an    agitated    crowd,    an    army 


312  THE  APPLICATIONS   OF   PHOTOGRAPHY. 

in  battle,  the  orator  as  he  speaks,  the  wave  as  it 
foams,  or  the  meteor  which  traces  its  luminous  track 
through  the  azure  of  heaven. 

We  could  still  recount  the  resources  which  the  art  of 
the  land-surveyor — geography,  history,  every  branch  of 
science  as  well  as  all  the  conceptions  of  human  learning 
—  will  one  day  find  in  photography  ;  but  the  reader,  after 
having  acquired  the  knowledge  of  the  actual  powers  of 
the  wonderful  invention  of  modern  times  which  is  the 
subject  of  this  volume,  will  himself  know  how  to  look  for 
the  future  applications  which  are  logically  derived  from 
those  actually  practised.  Instantaneous  photography, 
the  heliograph,  photography  naturally  coloured  by  the 
light  itself,  will  be  the  most  fruitful  branches  of  the  tree 
planted  by  Niepce  and  Daguerre  —  their  buds  have 
scarcely  yet  burst  from  the  stem,  but  they  already 
appear,  and  no  one  can  say  to  what  heights  they  may 
reach. 


^*^  In  the  Appendix  the  reader  will  find  some  for mulcB  of 
the  various  solutions  6^^.  einployed  in  the  Wet  Plate  and  Dry  Plate 
Processes  and  for  obtaming  paper  proofs.  Also  some  other  matters 
of  interest  which  it  was  difficult  to  give  in  the  body  of  the  work. 


313 


APPENDIX. 


PANORAMIC  Ph  0  TO  GRAPHY. 

If  a  photographic  camera  is  turned  round  upon  its  optical  centre  the 
image  of  an  object  will  appear  to  move  to  one  side  on  the  ground  glass.  In 
reality  the  image  remains  stationary  while  the  ground  glass  is  in  motion. 
Rotating  cameras  based  on  this  principle  have  been  constructed  at  various 
times.  One  of  the  best  was  that  invented  by  Mr.  Johnson,  and  called  the 
Pantas5opic  Camera ;  but  this  instrument  was  only  fitted  with  a  single  lens 
of  short  focus,  so  that  the  horizontal  lines  of  the  picture  were  always  slightly 
curved.  For  large  apparatus  of  this  kind  the  clockwork  by  means  of  which 
the  horizontal  motion  is  obtained  cannot  be  made  cheaply  and  accurately, 
and  at  best  it  is  easily  deranged,  and  can  only  be  repaired  by  a  skilhil 
mechanician,  and  such  would  certainly  not  be  found  in  regions  where  the 
finest  scenery  abounds.  The  large  angle  of  view  obtainable  by  the  rotating 
camera,  only  limited  by  the  length  of  the  dark  slide,  rendered  it  desirable 
to  introduce  a  simple  instrument,  not  easily  deranged,  that  could  be  adapted 
to  any  single,  double,  or  triple  lens,  suitable  alike  for  groups  and  landscapes, 
and  capable  of  producing  negatives  equal  to  those  taken  with  the  best 
stationary  cameras  now  in  use. 

It  appears  that  M.  Liesegang,  of  Diisseldorf  on  the  Rhine,  has  constructed 
a  simple  rotating  camera  which  was  employed  by  M.  Schultz,  of  Dorpat, 
in  taking  the  beautiful  groups  awarded  a  prize  medal  at  last  year's  Paris 
Exhibition.  The  bridges  and  views  taken  by  M.  Schoenscheidt,  of  Cologne, 
as  well  as  the  work  of  many  English,  Italian,  and  Indian  photographers, 
prove  the  success  of  the  invention.  M.  Liesegang  uses  a  stand  nearly  of 
the  common  tripod  form,  but  stronger  and  more  stable.  This  stand  carries 
a  large  polished  table  supplied  with  a  pivot  or  axis  on  which  the  camera 
turns.  The  pivot  is  so  adjusted  as  to  fall  into  the  same  plane  as  the  optical 
centre  of  the  lens. 


314 


APPENDIX. 


The  camera  is  half  as  broad  as  it  is  high,  and  has  a  slit  through  which  the 
rays  of  light  pass  which  form  the  image,  the  opening  of  the  slit  being  not  more 
than  a  quarter  of  an  inch  wide,  a  little  wider  only  where  the  near  fore- 
ground falls,  in  order  to  secure  a  longer  exposure  for  that  portion  of  the 
picture,  and  thus  impart  greater  uniformity  to  the  tone  of  the  negative. 
The  dark  slide  when  in  the  camera  is  closed  around  by  a  flexible  band,  the 
slit  only  being  left  open. 


PANORAMIC   CAMERA. 


The  two  motions  of  the  instrument,  viz.  that  of  the  frame  containing 
the  prepared  plate,  from  right  to  left,  and  the  motion  of  the  camera  on  its 
axis,  are  managed  by  a  simple  arrangement  of  horizontal  cords  and  pulleys. 
The  operator,  after  focussing,  has  only  to  turn  a  handle  to  take  in  the  wide 
scope  of  the  horizon,  or  a  group  of  friends  ranged  in  a  semicircle  round 
the  instrument.  The  other  operations  are  the  same  as  in  the  ordinary 
camera. 


APPENDIX.  3  I  5 


THE  HRLIOTYPE  PROCESS. 

The  Heliotype  process,  as  worked  by  the  Licensees  of  the  Heliotype 
Company  at  their  works  at  Kilburn,  is  based  upon  another  method  of 
utilising  the  action  of  light  upon  gelatine  rendered  sensitive  by  the  admix- 
ture of  bichromate  of  potash.  It  is  in  effect  a  development  of  the  Albert- 
type  process,  wherein  the  gelatine  itself  forms  no  part  of  the  picture,  as  in 
the  Woodburj'-type,  but  is  simply  used  as  a  printing  surface.  In  the 
Heliotype  process  the  gelatine  is  dissolved  in  warm  water,  and  a  sufficient 
quantity  of  bichromate  of  potash  is  added  to  make  it  sensitive  to  light, 
together  with  a  certain  proportion  of  chrome  alum,  to  render  it  very  hard 
and  durable.  This  solution  is  poured,  while  hot,  upon  a  glass  plate  pre- 
viously waxed  ;  the  film,  when  dry,  is  stripped  off,  and  exposed  to  light 
under  a  reversed  negative.  Having  thus  received  the  photographic  image, 
the  film  is  -made  to  adhere  to  a  metal  plate,  the  superfluous  chemicals  are 
soaked  out  in  water,  and  the  plate,  bearing  the  printed  surface  of  gelatine, 
is  placed  on  an  ordinary  printing  press,  inked  with  lithographic  ink,  and 
the  proofs  are  pulled,  on  either  plain  or  enamelled  paper,  in  the  ordinary 
way,  the  plate  being  damped  with  water  after  each  impression.  The  greasy 
ink  readily  adheres  to  the  deep  shadows,  which,  being  hard,  insoluble,  and 
non-absorbent,  have  repelled  the  water  altogether;  the  'high  lights,'  on 
the  contrary,  having  freely  absorbed  the  water,  repel  the  ink,  and  are  left 
perfectly,  white  ;  while  the  parts  representing  intermediate  gradations  of 
tone  retain  the  ink  in  such  degree  as  they  have  repelled  the  water.  This 
graduated  or  discriminative  power  of  absorption  renders  the  mechanically- 
printed  image  a  perfect  transcript  of  the  negative.  The  ink  used  may 
either  be  of  a  photographic  tone,  in  which  case  the  impressions  when  var- 
nished bear  a  close  resemblance  to  silver-prints ;  or  it  may  be  of  any  colour 
or  tint  desired,  to  ensure  a  close  resemblance  to  any  work  of  art  that  is 
being  copied.  Clean  margins  are  obtained  by  the  use  of  a  *  mask '  of  thin 
paper,  and  thus  the  necessity  of  'mounting' — so  objectionable  when  the 
prints  are  to  be  used  as  book  illus'^rations — is  avoided.  Surprise  has  often 
been  expressed  at  the  possibility  of  an  organic  substance  such  as  gelatine 
being  made  to  withstand  the  wear  and  tear  of  mechanical  printing.  But 
by  the  addition  of  chrome  alum  it  is  converted  into  a  substance  resembling 
horn,  and  as  a  matter  of  fact  several  thousand  impressions  have  been 
obtained  from  a  single  film.  The  effect  of  an  India  or  other  coloured  tint 
is  obtained  by  using,  instead  of  clear  water  for  damping  the  plate,  water 
with  a  small  quantity  of  some  dye  in  it.  The  Heliotype  process,  though 
for  some  purposes  inferior  to  the  Woodbury-type,  offers  special  advantages 
for  book-illustration,  and   has  been  adopted  with  success  in  many  artistic 


3l6  APPENDIX. 


and  scientific  works  of  importance.  One  of  the  strong  points  of  this 
process  is  the  fidelity  with  which  the  character  of  the  original  is  preserved, 
the  appearance  of  'glaze,'  common  to  all  silver  prints  on  albumenised 
paper,  and  inevitable  also  in  Woodbury-type  prints,  being  entirely  absent 
in  the  Heliotype. 


THE  PHOTO-TINT  PROCESS. 

This  process,  recently  perfected  by  Mr.  B.  J.  Edwards,  is  also  in  use  at 
the  same  works  as  the  above.  It  is  more  simple  than  the  Heliotype,  and 
while  adding  to  the  rapidity  and  certainty  with  which  the  prints  are  pro- 
duced, it  gives  finer  and  more  delicate  results.  The  frontispiece  to  this 
work  is  printed  by  the  photo  tint  process. 


EPITOME   OF  THE    WET   COLLODION  PROCESS  AND 
USEFUL  FORMULA. 

Negatives  should  be  taken  either  on  polished  flat  crown  glass,  free  from 
specks  and  scratches,  or  on  patent  plate  glass.  It  is  false  economy  to 
employ  glass  of  inferior  quality,  as  what  might  at  first  appear  only  a 
trifling  imperfection  in  the  plate  is  apt  to  spoil  the  finest  negative,  or  to 
cause  breakage  in  the  printing  frame. 

The  glass  plate  ought  to  be  chemically  clean '  when  prepared  to  receive 
the  collodion.     It  must  indeed  be  borne  in  mind  as  a  sort  of  maxim  that 

'  As  it  is  often  necessary  to  make  use  of  old  plates  which  it  is  a  difficult  matter  to 
get  perfectly  clean,  and  unless  they  are  clean  a  prolonged  development  of  the  image  will 
often  bring  up  stains  on  them,  the  following  simple  plan  may  be  adopted  :  First,  well 
wash  the  plates  in  water  containing  a  very  small  quantity  of  muriatic  acid  ;  rinse  in  plain 
water  ;  now  coat  the  plates  (which  after  drying  must  be  carefully  brushed  wtih  a  badger- 
hair  brush  to  remove  any  particles  of  dust)  with  a  quantity  sufficient  to  cover  the  plate 
of  a  mixture  made  as  follows,  and  used  fresh  : — 

To  2  quarts  of  water  add  7  drops  of  ammonia 
7  drops  of  acetic  acid 
The  white  of  one  egg 
Well  shake  and  filter. 

This  mixture  is  used  exactly  as  when  coating  the  plate  with  collodion,  except  that  any 
surplus  is  not  returned  to  the  bottle,  but  thrown  away.  The  plates  thus  coated  are  dried 
in  a  drying  rack  away  from  dust,  and  when  dry  may  be  used  at  any  time  for  receiving  the 
collodion  in  the  ordinary  way.  Plates  thus  prepared  do  not  readily  develop  stains  or 
show  scratches,  and  are  said  to  keep  longer  without  drying  in  hot  weather ;  a  great  aid  to 
the  landscape  photographer. 


APPENDIX.  317 


cleanliness  of  manipulation  and  methodical  care  are  the  chief  attributes  of 
the  successful  photographer. 

The  plate  is  first  coated  with  iodised  collodion  (see  p.  109).  Suitable  nega- 
tive collodion  and  iodising  solution  may  be  procured  in  separate  bottles, 
supplied  with  printed  directions,  from  any  photographic  dealer. 


SENSITISnVG  BATH. 


The  nitrate  of  silver  bath  is  next  used  for  immersing  the  collodionised 
plate,  and  may  be  prepared  in  the  following  proportions  : — 

Nitrate  of  Silver         .          .         .          .  i  ounce. 

Distilled  Water  .          .         .  •        ^5  ounces. 

Before  using  the  bath  (ioat  a' plate  with  iodised  collodion,  and  allow  it 
to  remain  in  the  solution  for  four  or  five  hours.  After  this  plate  has  been 
withdrawn  test  the  bath  with  a  piece  of  blue  litmus  paper ;  should  the 
paper  slowly  change  its  colour  to  red,  the  solution  may  be  filtered  through 
blotting  paper  and  used.  But  should'  the  test  paper  remain  unaltered  m 
colour,  add  one  or  two  drops  of  nitric  acid  to  the  bath,  so  as  to  render  the 
solution  slightly  acid  before  use. 


DARK  ROOM  OPERATIONS. 

When  a  collodionised  plate  has  been  immersed  in  the  sensitising  bath 
long  enough  to  get  quit  of  the  greasy  appearance  on  its  surface,  it  may  be 
removed,  placed  in  the  dark  slide  and  exposed  in  the  camera.  The 
operator  must  use  his  own  judgment  in  determining  the  duration  of  exposure. 
With  a  good  portrait  lens  in  a  favourable  light  it  will  vary  from  one  to  ten 
seconds.  The  plate  after  exposure  in  the  camera  must  be  brought  back  to 
the  dark  room  and  developed. 

1st  Developing  solution: — 

Protosulphite  of  Iron      ...  20  grains. 

Glacial  Acetic  Acid          ...  20  minims  (or  drops). 

Alcohol 30  minims. 

Water i  ounce. 


3l8  APPENDIX. 


Or, 

Ammonio-sulphite  of  Iron       .          .  20  grains. 

Glacial  Acetic  Acid         .         .         .  20  minims. 

Alcohol 30  minims. 

Water I  ounce. 

Either  of  the  above  solutions  may  be  employed  successfully  by  the 
beginner,  but  the  proportions  may  be  varied  to  such  an  extent  as  to  enable 
almost  every  photographer  to  use  his  own  favourite  developer. 

When  the  first  solution  has  been  washed  off,  the  re-developing  or 
intensifying  mixture  may  be  applied  in  quantity  sufficient  to  flood  the 
plate : — 

Pyrogallic  Acid  ....  3  grains. 
Citric  Acid  .....  3  grains. 
Water      ......         i  ounce. 

To  this  must  be  added,  just  before  using,  two  or  three  drops  of  a 
solution  of  nitrate  of  silver: — 

Nitrate  of  Silver  ....  30  grains. 
Water    ......  1   ounce. 

The  action  of  the  re-developer  must  be  carefully  watched  by  the  light 
of  the  yellow  window  in  the  dark  room,  and  arrested  when  the  high  lights 
of  the  picture  have  acquired  the  proper  intensity. 


FIXING. 

Wash  off  the  intensifier  and  consign  the  plate  either  to  a  bath  containing 
a  nearly  saturated  solution  of  hyposulphite  of  soda,  or  pour  over  its  surface 
a  weak  solution  of  cyanide  of  potassium  (100  grains  to  10  ounces  of  water). 
In  any  case  the  negative,  after  it  has  been  cleared  of  the  yellow  iodide  of 
silver,  must  be  thoroughly  washed  to  remove  all  trace  of  the  fixing  agent. 
It  is  then  dried  and  varnished. 

The  negative  varnish,  which  may  be  had  from  any  photographic 
chemist,  is  applied  in  the  same  way  as  collodion,  but  the  plate  must  be 
first  slightly  heated.  The  operator  cannot  go  far  wrong  in  following  the 
printed  directions  on  the  bottle. 


APPENDIX.  319 


POSITIVE  SILVER-PRINTING  FORMULA. 

As  the  various  operations  connected  with  positive  printing  are  described 
in  these  pages,  it  is  needless  to  do  more  here  than  to  supply  useful  formulae 
for  ready  reference. 

Sensitising  bath  for  albumenised  paper  : — 

Nitrate  of  Silver     ....         60  grains. 
Water i  ounce. 

Toning  solution : — 

Chloride  of  Gold     ....  I  grain. 

Bicarbonate  of  Soda        ...  4  grains. 

Water   ......  6  ounces. 

The  toning  solution  may  be  used  two  or  three  minutes  after  it  has  been 
made. 

Fixing  solution: — 

Hyposulphate  of  Soda     ...         4  ounces. 
Water     ......  i  pint. 

The  toned  prints,  after  they  have  remained  from  fifteen  to  twenty 
minutes  in  the  fixing  solution,  may  be  removed  and  thoroughly  washed  in 
repeated  changes  of  water,  and  allowed  to  soak  for  twelve  hours,  when 
they  may  be  dried,  cut,  and  mounted. 

Sago,  well  boiled  and  strained  through  muslin,  makes  an  excellent 
mounting  paste. 


SIMPLE   METHOD    OF  PREPARING  DRY  PLATES. 


By  the  kind  perjuissicn  of  Canon  Beechy  and  the  Editor  we  are  able  to 
print  the  following  interesting  and  useful  extract  from  *  The  British 
Journal  of  Photography,'  No.  804,  Vol.  XXII.,  October  i,  1875. 


1.  Always  have  in  stock  the  following  articles  : — 

Absolute  Ether 1  pint. 

Absolute  Alcohol i      ,, 

Alcohol    820 I      ,, 

Hydrochloric  Acid i      ,, 

(Tlie  latter  is  as  useful  in  cleaning  the  plates  for  albumenising  as  for  the  emulsion.) 
Gun  Cotton  of  suitable  quality,  at  least         .         .         i  ounce. 

Bromide  of  Cadmium 1      ,. 

Pyrogallic  Acid       .......         1      „ 

Fused  Nitrate  of  Silver  in  powder         ,         .         .         1      „ 
The  above  constitute  all  the  chemicals  employed  in  the  manufacture  of  these  plates. 


320  APPENDIX. 


2.  Have  also  in  stoc'-,  ready  for  use  at  any  moment  (a),  at  least  two  dozen  properly 
albumenised  plates,  and  {i)  a  stock  bottle— say  eight  ounces — of  the  following  bromide 
solution  : — In  eight  ouncesof  absolute  alcohol  dissolve  five  drachms  of  anhydrous  bromide 
of  cadmium.  The  solution  will  be  milky.  Let  it  stand  at  least  twenty-four  hours,  or 
until  perfectly  clear.  It  will  deposit  a  white  powder.  Decant  it  carefully  into  an  eight- 
ounce  vial,  and  add  to  it  one  drachm  of  strong  hydrochloric  acid.  Label  it  'bromide 
solution."  It  is  as  well  to  add  on  the  label  the  constituents,  which  will  now  be  found  to  be 
nearly — 

Alcohol         .• I  ounce. 

Bromide  of  Cadmium 32  grains. 

Hydrochloric  Acid 8  drops. 

This  solution  will  keep  for  ever,  and  be  sufficient  to  last  the  amateur  two  or  three  years. 
With  it  at  hand  he  is  now  able  in  two  days  to  prepare  a  batch  of  plates  at  any  time.  In 
doing  so  he  wi  1  proceed  thus  : — 

3  Settle  how  many  plates  you  mean  to  make  and  take  of  the  above  accordingly.  For 
two  dozen  half-plates  (6^  x  4J)  {a)  dissolve  by  heat  over  (but  not  too  near)  a  spirit  lamp, 
and  by  a  yellow  light,',  forty  grains  of  nitrate  of  silver  in  one  ounce  of  alcohol  820. 
Whilst  this  is  dissolving  in  a  little  Florence  flask,  on  a  retort  stand  at  a  safe  distance  from 
the  lamp  (which  it  will  do  in  about  five  minutes),  take  of  the— 

ijj)  Bromised  Solution \  ounce. 

Absolute  Ether i      ,. 

Gun  Cotton 12  ^jt\^ 

Put  these  into  a  clean  bottle,  shake  once  or  twice,  and  the  gim  cotton,  if  good,  will 
entirely  dissolve.  As  soon  as  the  silver  is  all  dissolved,  and  whilst  quite  hot,  pour  out  the 
above  bromised  collodion  into  a  clean  four-ounce  measure,  having  ready  in  it  a  clean  slip 
of  glass.  Pour  into  it  the  hot  solution  of  nitrate  of  silver  in  a  continuous  stream,  stirring 
rapidly  all  the  while  with  the  glass  rod.  The  result  will  be  a  perfectly  smooth  emulsion 
without  lumps  or  deposit,  containing,  with  sufficient  exactitude  for  all  practical  purposes, 
eight  grains  of  bromide,  sixteen  grains  of  nitrate  of  silver,  and  two  drops  of  hydrochloric 
acid  per  ounce.  Put  this  into  your  stock  emulsion  bottle  and  keep  it  in  a  dark  place  at 
least  twenty-four  hours.  When  first  put  in  it  will  be  tuilky  ;  when  taken  out  it  will  be 
creamy.  It  is  well  to  shake  it  once  or  twice  in  the  course  of  the  twenty-four  hours  ;  but 
do  not  always  do  so. 
4.  At  the  end  of  twenty-four  hours  you  can  make  your  two  dozen  half-plates  in  little 
more  than  an  hour.  Proceed  as  follows  : — Have  two  porcelain  dishes  large  enough  to  hold 
six  (or  four,  at  least)  of  your  plates.  Into  one  put  sufficient  clean,  filtered  rain  water  to 
nearly  fill  it.  Into  the  other  put  thirty  ounces  (a  pint  and  a-half )  of  clear,  flat  (not  acid) 
table  beer,  in  which  you  have  dissolved  thirty  grains  of  pyrogallic  acid.  I  rea  ly  do  not 
know  a  simpler  or  more  satisfactory  preservative  than  the  above.  I  like  to  use  bitter 
beer  at  one  shilling  per  gallon.  The  pyro.  dissolves  in  it  at  once.  Pour  it  through  a 
filter  into  the  dish,  the  neck  of  the  funnel  being  within  half-an-inch  of  the  bottom,  to  avoid 
bubbles.  If  allowed  to  let  stand  an  hour  any  beer  will  be  flat  enough.  If  the  beer  be  at 
all  brisk  it  will  be  difficult  to  avoid  little  bubbles  on  the  plates.  At  all  events,  let  your 
preservative  stand  whilst  you  filter  your  emu'sion.  This  must  be  done  through  cotton- 
wool into  a  perfectly  clean  collodion  bottle.  Give  the  emulsion  a  good  shaking,  and  when 
all  bubbles  have  subsided  pour  it  into  the  funnel  and  it  will  all  go  through  in  five  minutes. 
The  filtered  emulsion  will  be  found  to  be  a  soft,  smooth,  creamy  fluid,  flowing  easily 
and  equally  over  the  plates.  Coat  with  it  six  plates  in  succession  (if  your  dishes  will  hold 
six),  and  place  each  as  you  coat  it  in  the  water.  By  the  time  the  sixth  is  in  the  first  will 
be  ready  to  come  out.  Take  it  out,  see  that  all.greasiness  is  gone,  and  place  it  in  the 
preservative.  Coat  another  plate  and  put  it  in  the  water  where  the  first  came  out.  Remove 
your  second  plate  from  the  water  into  th'e  preservative,  and  in  its  place  lay  another  freshly 
coated  plate,  and  so  on  until  the  first  six  are  all  in  the  preservative  and  six  more  in  the 
water.  You  now  take  the  first  plate  out  of  the  preservative  into  your  drying-box,  and 
again  remove  the  first  out  of  the  water  into  the  vacant  place  in  the  preservative.  Coat 
another  and  put  it  into  the  vacant  place  in  the  water.  Take  your  second  plate  out  of  the 
preservative  into  the  drying-box  and  the  second  out  of  the  w^er  into  the  preservative, 

'  If  ordinary  bromide  be  used,  thirty-two  grains  of  silver  will  be  sufficient. 


APPENDIX.  32 


and  so  on  till  all  your  plates  are  through  the  process  and  locked  up  safely  in  the  drying- 
box.  By  proceeding  as  above  not  a  moment  of  time  is  lost,  and  yet  each  plate  soaks 
sufficiently  in  the  water  and  in  the  preservative.  You  will  find  an  hour,  if  you  are  dex- 
terous, sufficient  time  for  two  dozen  plates. 

As  it  is  my  wish  to  render  this  process  so  practical  and  simple  that  amateurs  may 
make  their  own  plates,  the  following  particulars  as  to  material,  exposure,  and  development 
will  not  be  de  trap : — 

1.  As  to  materials  :  I  recommend  all  to  be  got  from  some  eminent  photographic  che- 
mist. There  are  many  such  :  in  every  large  town  at  least  one.  I  obtained  my  pyroxyline 
from  Mr.  Ronch,  of  Norfolk-street,  who  also  made  my  dr>'ing-box  from  my  instructions, 
than  which  nothing  can  work  better.  It  holds  twenty-four  half-plates,  has  a  sheet-iron 
bottom,  with  air-tubes  supplying  hot,  fresh  air  between  every  two  plates.  I  generally 
make  my  plates  at  night,  and  when  they  are  all  in  the  rack  and  locked  up  I  light  a  spirit 
lamp  containing  one  ounce  of  methylated  spirit,  under  the  drying-box,  and  go  to  bed.  In 
the  morning  I  may  pack  up  my  plates  and  set  out  on  my  expedition,  confident  that  I  have 
two  dozen  reliable  dry  plates. 

2.  As  to  exposure  :  these  plates  do  not  profess  to  be  zvry  rapid,  but  they  are  sufli- 
ciently  so  for  every  ordinary  purpose.  From  thirty  to  sixty  seconds  according  to  light  will 
be  enough,  but  they  will  do  with  less  and  bear  strong  ammonia  development  without 
fogging  :  or  they  will  do  with  more,  the  development  being  stopped  sooner.  Unless  you 
take  with  you  the  means  of  developing  it  is  better  to  tiy  a  plate  before  j-ou  start.  In 
spite  of  every  precaution  there  will  somehow  be  a  difference  in  a  batch  of  plates  now  and 
then.  I  may  mention,  also,  that  I  never  back  my  plates,  for  the  reason  that  I  never 
find  they  require  it.  They  will  not  blur  with  any  light  that  will  not  also  blur  backed 
plates. 

3.  For  developing  I  use  Colonel  Wortley's  strong  developer.  I  mean  the  one  published 
with  his  excellent  rapid  uranium  plates,  which  I  copy  : — 

A.  Pyrogallic  Acid 96  grains. 

Alcohol I  ounce. 

B.  Bromide  of  Potash 12  grains. 

Water i  ounce. 

C.  Carbonate  of  Ammonia 64  grains. 

Hot  Water i  ounce. 

By  all  means  use  carbonate  of  ammonia.  The  liquid  ammonia  often  destroys  a  good 
negative,  and  always  gives  a  more  inky  picture.  For  a  half-plate  take  of  A  thirtj'  drops, 
of  B  sixty  drops,  of  C  two  drachms,  or  even  three  if  the  exposure  be  short.  I  never  use 
any  alcohol,  but  simply  wet  the  plate  well  under  the  tap,  thereby  washing  off"  the  beer, 
and  pour  on  the  developer.  The  picture  will  come  out  in  a  few  seconds.  On  its  first 
appearance  pour  back  the  developer  into  the  measure  and  let  the  picture  come  out  of  itself. 
You  will  be  surprised  to  see  how  it  7£////come  out.  You  can  then  judge  as  to  exposure 
and  proceed  according'y,  adding  bromide  if  too  rapid,  or  pouring  on  the  developer  as  it 
was  if  all  right,  or  with  an  extra  thirty  drops  of  C  if  under-exposed.  These  plates  seldom 
require  to  be  intensified.  If  they  do  the  ordinary  acid  silver  and  pyro.  redeveloper  will 
bring  them  up  easily  and  at  once.  Clear  with  either  hypo,  or  cyanide  as  you  please,  and 
if  you  intensify  do  it  after  clearing  ;  but  the  beer  gives  these  plates  a  bottle-green  tint, 
which  is  more  impervious  to  actinic  light  than  from  its  transparency  you  wou'd  suppose. 

These  p'ates  are  more  rapid  if  placed  at  once  in  the  preservative  without  washing  ; 
but  they  require  to  stay  in  till  all  greasiness  has  disappeared,  and  I  doubt  if  they  keep  as 
well  or  are  so  certain.     To  wash  first  is  safest  for  amateurs. 

In  conclusion  :  I  am  glad  you  have  asked  me  for  the  above  formulae,  since  I  have  had 
more  letters  enquiring  for  them  than  I  could  find  time  to  answer.  I  claim  nothing  new 
in  the  process  but  the  beer  and  pyro.  preservative.  You  know  I  am  a  pupil  of  Colonel 
Wort  ley,  and  my  process  is  essentially  his  applied  to  a  humbler  and  more  domestic  class 
of  plates.  I  have  tried  to  simplify  their  preparation  for  amateurs,  and  I  am  quite  sure 
ninety-nine  out  of  a  hundred  will  pre'er  them  to  the  host  of  complications  which  from 
time  to  time  'go  up  like  a  rocket  and  come  down  like  a  stick.' 


322  APPENDIX. 


WEIGHTS    AND    MEASURES, 

ENGLISH. 

Troy    Weight. 
20  Grains       =   i  Scruple.   9. 

3  Scruples   =   i   Drachm.   3. 

8  Drachms  =   i  Ounce.   % 
12  Ounces      =  i  Pound,    lb. 

480*0  Grains  Troy  =  i  Oz.  Troy. 

437*5       ,,         ,,  =1  Oz.  Avoirdupois. 

yooo'O       ,,         ,,  =  I  Pound       ,, 

5760*0       ,,         ,,  =1  Pound  Troy. 

I   Minim  (or  drop)  =  I  Minim. 

60  Minims  =   I  Fluid  Drachm,  f  5. 

8  Fluid  Drachms  =   i  Fluid  Oz.  f  5. 

20  Fluid  Ounces  =   i  Pint,  octarms. 

8  Pints  =•   I  Gallon,  congius. 

FRENCH. 

The  French  Kilogramme  (=  to  about  2  lbs.  3  oz.  4^  drachpis  Avoirdu 
pois)  is  the  weight  of  a  cubic  decimetre  of  distilled  water  at  the  temperature 
of  maximum  density,  39°  '2  Fahrenheit. 

One  kilogramme  =  10  hectogrammes  =  100  decagi-ammes  =  1,000 
grammes  =  10,000  decigrammes  =  100,000  centigrammes  =  1,000,000 
milligrammes. 

(The  French  gramme  =  15*4325  English  grains.) 

The  Kilolitre  is  a  cubic  decimetre. 

I  kilolitre  (^  10  hectolitre  @,  10  decalitre  @  10  litre  @,  10  decilitre  @ 
10  centilitre  @  10  millilitre. 

(The  French  litre  =  1*76  Imperial  pint,  i.e.  about  35  oz.) 

The  Metre,  the  unit  of  the  entire  system  of  weights  and  measures 
known  as  the  metrical  system,  is  assumed  to  be  the  0*000010  part  of  the 
quadrant,  or  the  0*000040  of  the  whole  globe  measured  over  the  poles. 

I  metre  (=  3*2808  feet  or  about  39  inches)  =  10  decimetres  =  100 
centimetres  =  1,000  millimetres. 

I  metre  =  0*1  decametre  =  O'Oi  hectometre  =  0*001  kilometre. 
I  kilometre  =  1093*633  yards. 

I  Parisian  foot  =  i  *o658  English  foot. 


INDEX. 


negatives, 


79 


ACC 

A  CCIDENTS     with 
-^     141 

Albertype,  t^e,  193 
Albumenised  paper,  123 
Alchemists  (the),  6 
Applications  of  photography, 
Arago,  55,  184 
Archer  (Scott),  86 
Arrangements  for  lighting,  89 
Astronomical  photography,  249 
Autotype  Co.,  147 

t)  ALDUS,  161,  190 
■'-'     Balm  of  Judaea,  35 
Barometrograph,  272 
Becquerel,  M.  E.,  169 
Beechey's  (Canon)  dry  plate  process, 

319 

Bellows  camera,  98 
Bichloride  of  mercury,  128 
Bisulphate  of  iron,  116 
Blanquart-Evrard,  64 
Bouton,  17 

r^AMARSAC'S  process,  214 
Camera  obscura,  2 


DAR 

Camera  (simple),  97 

—  (twin-lens),  loi 

—  stand,  99 
Cameras  and  lenses,  89 
Carbon  print,  162 
Carrier-pigeon  post,  235 
Catacombs,  the,  303 
Celestial  photography,  249 
Charles  (Professor),  10 
Chevalier,  20 

Chinese  tradition,  9 
Chloride  of  silver,  6 
Cleaning  the  plate,  105 
Clouds,  methods  of  obtaining, 
Coating  the  plate,  109 
Collodion,  79,  86 
Coloured  proofs,  143 
Cyanide  of  potassium,  1 1 7 

■pjAGUERRE,  14 

Dagiierreotype,  53 
Dark  room,  the,  2,  89 

—  operations,  317 

—  slide,  100 

—  tent,  137 


i38 


Y  2 


234 


INDEX. 


DAV 

Davy  (Sir  H.).  12 

Degotti,  14 

Delaroche  (Paul),  63 

Dc  la  Rue,  253 

Developer  for  negatives,  114,  317 

Developing  agent,  5 1 

—  of  the  picture,  105 
Development  of  image,  1 1 3 
Diorama  (the),  17 
Dipping  bath,  112 
Donne,  M.,  180 

Dry  process,  154,  1 5  7,  319 

pARLY  heliotypes,  180 

Electrograph,  photo-,  277 
Enamelled  Photographs,  214 
English  weights  and  measures,  320 
Epitome  of  wet  Collodion   process, 

316 
Enlarging,  147 
Exposure  in  camera,  113 

pABRICI.US,  6 

Fixing  of  colours,  169 

—  of  the  picture,  105 

—  the  negative,  1 17,  318 

—  the  print,  128,  318 
Fizeau,  180 
Focussing  glass,  98 
Formic  acid,  116 

French  weights  and  measures,  320 
Future  of  photography,  the,  306 

/^ALLIC  acid,  161 

Gamier  and  Salmon,  192 
Gelatino-bromide  process,  157 
Goupil,  M.,  200 
Greeks,  the,  5 
Grubb,  253 
Gun  cotton,  79,  85 


MIC 

"LTALL  (Mr.  Asaph),  260 
Harvard  College,  259 
Flead  rest,  103 
Heliography,  38,  179 
Heliotype  process,  the,  315 
Herschel  (Sir  John),  78,  80 
Hill,  Mr.,  171 
'  Horn-silver,'  7 

Hyposulphite  of  soda,  67,  79,  117, 
318 

TMAGE,  development  of,  105 
—  intensifying  of,  105 

—  fixing  of,  105 

—  varnishing  of,  105 
Instantaneous  photography,  140,  283 
Intensifying,  116,  318 

Intensity  of  light,  279 
Iodide  of  potassium,  133 
Is  photography  art?  297 

T   ANDSCAPE  photography,  93, 

^     113 

Land  surveying,  306 

Lasteyrie-Dussaillant  (Count  de),  30 

Legray,  M.,  161 

Lemercier,  M.,  189 

Lenses  and  cameras,  89 

Liebert's  enlarging  apparatus,  150 

Light,  the  influence  of,  89 

Lithography,  30 

'  Luna  cornea,'  7 

TV/TADAME  de  Stael,»i46 

Magnetic  needle,  the,  276 
Magnesium  light,  the,  302 
Manipulation,  105 
Megascope,  the,  148 
Meteorology,  269 
Microscopic  despatches,  235 


INDEX. 


325 


Microscopic  photography,  220 
Modern  heliography,  195 
Monckhoven's  enlarging  camera,  149 
*  Moniteur  Universel '  (the),  54 
Monostereoscope,  287 
Mounting  the  print,  129 

TSJATIONAL  reward,  61 
Negative  (the),  105 

—  characteristics  of  a  good,  1 20 
Niepce  (Isidore),  31 

—  Joseph  Nicephore,  25,  26 

—  de  Saint- Victor,  182 


/^BERNETTER'S  process,  195 

Oil-coloured  proofs,  143 
Orthoscopic  lens,  136 
Out-door  photography,  93,  135 
Over-exposure,  effect  of,  115 

pAINTED  photographs,  143 
Panoramic  photographs,  307, 

313' 

Panoramic  photography,  313 
Pantascopic  camera,  313 
Paper  proof,  122 
Permanent  carbon  process,  167 
Pin  holes  in  negative,  1 20 

—  and  spots,  141 
Phosphorus,  35 
Photocromos,  175 
Photo-electrograph,  277 
Photoglypty  (or  the  Woodbury  pro- 
cess), 199 

Photographic  astronomy,  249 

—  caricatures,  143 

—  despatches,  235 

—  enamels,  214 

—  operations,  &c.,  89 


REG 

Photographic  processes,  89 

—  printing,  169 

—  registering  instruments,  2C9 
Photography  and  art,  297 

—  in  war,  306 

—  and  crime,  310 

—  discovery  of,  i 
Photography,  landscape,  94 

—  on  paper,  64 

—  on  glass,  79 
Photolithography,  187 
Photometry,  279 
Photomicrography,  220 
Photo-sculpture,  208 
Photo-tint  process,  316 
Plate  box,  119 

—  cleaning  of  the,  105 

—  coating  with  collodion,  105 

—  exposure  of  in  camera,  105 

—  sensitising  in  bath,  105 
Poitevin,  M.,  174 

—  Heliotype  researches,  183 
Polemoscope,  307 
Political  Photographs,  145 
Porta,  J.  B.,  2 

Portable  apparatus,  136 
Positive  proof  on  paper,  122,  318 

—  silver  printing  formulae,  3 1 8 
Pouncy,  Mr.,  163 

Practice  of  photography,  132 
Printing  frame,  124,  126 

—  from  the  negative,  124 
Problems  to  be  solved,  169 
Processes,  153 

Properly  timed  exposure,  1 16 
Pyrelophore,  the,  28 


"DACK  for  dr)'ing  plates,  118 

Registering   photographic  in- 
struments, 268 


326 


INDEX. 


RET 

Retouching,  141 
Rolling  the  print,  129 
—  press,  129 
Rotating  Camera,  313 
Russell,  Major  C,  156 
Rutherford,  253 

C  AINT-VICTOR    (Niepce  de)  7 

Salmon,  Mr.,  163,  192 
Salted  paper,  123 
Scheele,  10 
Schoenbein,  85 
Secchi,  253 
Seebeck,  175 
Senefelder  (Aloys),  30 
Sensitised  paper,  preparation  of,  122 
Sensitising  bath,  3 1 7 
Sensitising  the  plate,  105,  318 
Simple  dry-plate  process,  319 
Sitting  or  posing  room,  89 
Smoked  pictures,  42 
Solarisation,  137 

Stains  and  streaks  in  negative,  120 
Starch  paste,  130 
Stereoscope,  the,  287 
Stereoscopic  vision,  287 
Studies  of  skies,  137 
Studio  and  apparatus,  89 
Sub-chloride  of  silver,  133 
Swan,  Mr.,  163 

n^ALBOT,  64,  75,  182 
Tannin  process,  156 


woo 
Telegraphic  photography,  309 
Terrace  for  printing,  89 
Theory  of  photography,  152 
Thermograph,  271 
Thermometer,  registering,  271 
Thermometrograph,  275 
Toning  the  print,  127,  319 
Tourist  Photographer,  135 
Transit  of  Venus,  260 
Twin-lens  camera,  loi 

T  JNDER  exposure,  effect  of,  115 

WAPOURS  of  mercury,  51 

Varnishing  of  the  picture,  105 
Varnishing  negative,  118 
View  lenses,  135 
Vigier,  M.,  161 
Vignette  glass,  125 
—  pictures,  125 

Vignetting,  simple  method  of,  125 
Vitrified  photographs,  214 
Vitruvius,  6 
Voglander,  M.,  71 

V\7AR  and  Photography,  306 

Warren  de  la  Rue,  251 
Watt  (James),  12 
Waxed  paper  process,  159 
Wedgwood,  11,  12 
Willeme,  M.,  208 
Wheatstone's  stereoscope,  287 
Woodbury,  Mr.,  199 


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(Factories,  Horatio  and  Jane  Streets,  New  York.) 

Manufacturers  of  Artists'  Oil  Colors,  in  Tutes; 

CAPAS,  ACADEMY  BOARDS,  MILLBOARDS.  AND  OIL-SKETCHING  PAPERS; 
FINE     BRUSHES     FOR     OIL     AND     WATER     COLOR     PAINTING, 

VARNISHES,     WATER    COLOR    LIQUIDS,    OILS,    Etc. 
Drawing  Papers,  Sketching  Books  and  Blocks,  Pencils,  Mathematical  Instru- 
ments, Charcoal  and  Crayon  Drawing  Materials,  Illustrated  Books  on 
Art,  Folding  and  Studio  Easels.  Drawing  Boards,  Studies,  Manikins 
and   Lay   Figures,    Out-of-Door    Sketching   Boxes. 

WINSOR    &    NEWTON'S    CAKE    AND     MOIST    WATER     COLORS, 

Tube  Colors,  Canvas,  Etc. ;  also,  French  and  German  Goods. 
SCULPTORS'  TOOLS,  MODELING  WAX  AND  CUY,  PUSTER  CASTS  FOR  MODELS, 

ANTIQUE    POTTERY    AND    PORCELAIN    TILES, 

With  Materiils  for  Pottery  and  China  Decoration. 
Fresco  Designs  and   Colors,  and  Brushes   for   Fresco  and  Scenic  Painting. 
Wax  Flower  Supplies — Colors,  Tools,  Moulds  and  Brushes. 
Manufacturers   of   White    Lead,    Zinc    White,  Colors   and  Varnishes. 


FRED'K    W.    DEVOE. 
JAMES    F.    DRUMMONP. 


FRED'K    SAUNDERS,    JR., 
J.    BEAVER    PAGE. 


A  dvertisements. 


THOS.  H.  McCOLLIN, 
Photographic  Chemist, 

634  Arcli  Street,  Philadelphia,  - 

IMPORTER    AND    DEALER    IN 

Foreign  Photographic  Spocialties. 

Refiner  of  PliotOErapMc  Golfl  &  Silver  Wastes. 

SOLE  MANUFACTURER  OF 

McCollin's  Delicate  Half-Tone  Collodion, 

.  McCOLLIN'S  SILICATED  CASTOR  yARNISH. 

SOLE  AGENT  FOR 

American  Collodion  Pellicle  Emulsion, 

MOKaiM'S  AILBIUMEIIZE©  PAPEKS 

AND 

LAMBERTYPE  MATERIALS, 

And  Licenses  for   Carbon  iFork  in  the  States  of  Pennsyl- 
vania, New  Jersey  and  Delaware,  <0c.,  <f  c. 


SEND  FOR  CATALOGUE. 


Advertisements. 


BENERMAN  &  WILSON, 

116  lortli  Seventh  St.,  PMladelpMa. 


Centennial  Views  and  Lantern  Slides. 

THE  PHILADELPHIA    PHOTOGRAPHER,  $5  per  year. 
ROBINSON'S  TRIMMERS  AND  GUIDES. 
WAYMOUTH'S   VIGNETTE    PAPERS. 
"SOMETHING   NEW." 

THE    MAGIC    LANTERN,  $1  per  year. 
PHOTOGRAPHIC   BOOKS. 

HERMAGIS'    FRENCH    LENSES. 

GIHON'S   CUT-OUTS   AND   OPAQUE. 
"TO   MY   PATRONS." 

WILSON'S  "LANTERN   JOURNEYS,"  12. 
MAGIC  LANTERNS   AND    SLIDES. 


Of  the    latter   AAre    have    the 

Largest  Stock  in  A.merica. 


Advertise^nenis, 


J 


imm 


(Late  with  A.  P.  Hall,) 
1005      MAIN      STREET 

(Opposite  Grant  House.) 


Wheeling,  West  Va. 


ALL  GOODS    USED    IN    THE 


Art  of   Photography, 

APPARATUS,  CHEMICALS, 


FRAMES    AND     MOULDINGS. 


A    FULL    ASSORTMENT    OF 


Papers,  Mats,  Picture  Cord,  Glass,  &c.,  &c. 


PERSONAL  ATTENTION  GIVEN  TO  ALL  OEDEfiS. 


Advertisements. 


NOW    COMPLETE. 


ART   JOURNAL. 

A  volume  of  exquisite  beauty,  containing  upward  of  Thirty  Steel-plate 
Engravings.     These  alone  would  please  the  eye  forever. 

As  a  periodical  connected  with  Fine  Arts  it  is  unparalled  on  this  Continent. 

It  has  a  proud  reputation,  not  only  in  America,  but  in  England. 

The  best  artists  and  authors  are  employed  in  its  production. 

The  most  skilled  printers  are  engaged  in  its  illustrations  and  letter-pres^* 

The  Art  Features  of  the  Centennial  Exhibition  are  well  represented. 

It  is  the  only  journal  that  gives  expression  to  the  mind  of  the  artist  and 
art  critic. 

As  a  book  to  place  on  a  drawing-room  table  it  is  unequaled  for  its  variety. 

It  is  indispensable  to  every  one  who  desires  to  keep  pace  with  the  world 
of  Art — whether  in  Painting,  Sculpture,  Architecture,  Furniture,  Household 
Decoration  or  Ceramics. 

No  refined  home  ought  to  be  without  the  Art  Journ.\l. 

It  is  a  perpetual  feast  for  the  mind,  because  it  is  associated  with  the  beautiful 
Price,  in  Cloth,  gilt  edges,  $13.00/  Half  Morocco,  gill  edges,  $15.00;  Full  Morocco, 

gilt  edges,  ^rS.oo. 

TO  SUBSCRIBERS  ONE   DOLLAR   LESS. 


What  the  press  of  Neiv  York  City  say  : 
"  D.  APPLETON  &  CO. 
*'  Among  the  few  publishers  of  works  of  unquestioned  merit  in  this  city, 
is  D.  Appleton  &  Co.  In  the  multitudinous  productions  of  this  house  it  is 
wonderful  to  see  how  few  there  are  not  of  value  and  worth.  The  buyer  there, 
no  matter  how  inexperienced,  is  sure  to  get  the  worth  of  his  money.  In 
speaking  thus  we  refer,  of  course,  to  the  exclusive  publications  of  the  house. 
Now,  there  is  Appletons'  Art  yournal,  for  instance.  In  this  country  a  more 
complete  or  finished  book  was  never  sent  forth.  In  typography,  in  its  artistic 
construction,  it  is  more  perfect  than  anything  American  ever  seen  before.  Each 
number  of  this  admirable  periodical  contains  three  steel  engravings  on  heavy 
plate  paper,  from  the  rarest  and  most  beautiful  pictures  in  the  world.  These 
engravings  are  prepared  regardless  of  expense.  One  recently  produced  cost 
no  less  than  S700  in  gold.  In  every  respect  it  is  an  art  journal,  and  no  family 
of  taste  in  the  country  should  be  without  it." — From  Commercial  Advertiser, 
December  14,  1876. 


Subscriptions  received  by  the  publishers  or  their  Agents.  Agenciep:  22  Hawley  st.,  Bos- 
ton; 922  Chestnut  at.,  Philadelphia;  22  Post  Office  Avenue,  Baltimore;  53  9th  st.,  Pittsbarg; 
100  State  St.,  Albany ;  42  State  sn.,  Rochester ;  103  State  st.,  Chicago ;  30  W.  4th  st.,  Cincinnati ; 
805  Locust  St.,  St.  Louia;  20  St.  Charles  st..  New  Orleans;  230  Sutter  st.,  San  Francisco. 

D.  APPLETON  A  CO.,  Publishers. 

549  &  551  Bboadwat,  New  Yobk. 


Advertisements. 


t:h:e 


FIOfOIBlFIIG   flMlS. 

A  Monthly  Journal  devoted  to  Practical  and 
Commercial  Photography. 

It  contains  twenty-four  pages  of  useful  matter. 

Subscription  price,  $1  per  annum,  postage  paid,  including  one 
copy  Photographic  Mosaics  for  1876  as  a  premium. 

We  give  it  to  all  readers  of  the  Philadelphia  Photographer,  with 
which  journal  the  Photographtc  Times  is  bound  each  month,  besides 
which,  it  has  a  long  list  of  independent  subscribers,  thus  making  its 
circulation  much  larger  than  that  of  any  photographic  journal  in  the 
country. 

The  advantages  to  advertisers  are  therefore  apparent. 

We  will  accept  a  limited  number  of  advertisements  at  the  follow- 
ing rates  : 

One  page,  one  time $20  00 

^  ^'f  page,  one  time 12  00 

Quarter  page,  one  time 7  00 

Special  terms  for  advertisements  for  a  longer  period. 

SOOVILL  MANUFAOTUEING  CO.,  Publishers, 

4:10  ^  421  Broome  Street,  New  York. 


Advertisements.  3 

John  a.  Hood.  Wm.  D.  H.  Wilson. 

^VSO^,  HOOD  &  COMP^j^ 

^  Fo.  822  ARCH  STREET,  S 

PHILADELPHIA, 

MANUFACTURKRS    AND  IMPORTERS  OF  AND    DEALERS  IN 

Photographic  Materials 

FRAMES, 

STEREOSCOPES, 

AND  VIEWS. 


SOLE    AGEN  TS 


Ross  AND  Steinheil  Lenses 


Orders  solicited. 

Price  Lists  gratis  to  all  applicants. 

TRADE  AGENTS  FOR  THE  PUBLICATIONS  OF  THE 

CENTENNIAL  PHOTOGRAPHIC  COMPANY. 


A  dvertisements. 


tttwod's  pniic  Jtlti'lial. 


C.  H.  GRAVES  &  SONS 


35  HAVS^KINS  STREET, 

S@8ir©H,    SASS. 


The  above  brand  of  Alcohol  is  distilled  with  great  care, 
and  is  pecjdiarly  adapted^  to  the  wants  of  the  Photo- 
graphic trade.  Stoch  dealers  may  be  interested,  to  hnow 
that  all  our  Alcohol  is  drawn  from  a  sealed  measure, 
and  we  warrant  casks  to  hold  just  what  we  bill  them. 

Barrel  Orders  may  be  addressed  to  the  manufac- 
turers. 

At  retoAl  by  every  live  and  reliable  Stoch  House  in 
the  United  States. 


Adveriisemenis. 


Lewis  Pattberg  &  Bros. 

MANUFACTURERS  OF  FINE 

VELVET    FRAM  ES, 

"GILT  OR  NICKEL," 
FOR    TRANSPARENT     PICTURES; 

passe  paifteittst 
E  isT  C3- Xj  I  s  h:    3Nwd:^a?s, 


AND  ALL  KINDS  OF 


FANCY  BRASS  WORK. 


FACTORY: 

Jersey    City    Heights,    N.  J. 

WAREROOM    AND    OFFICE: 

IN'o.  709    Broadway,   ItsT.  Y. 


Advertisements. 


184=3 


1877 


"THE    OLD    HELIABLE' 


x)e:fot, 

ES  TA  BUSHED    THIR  T  Y-FO  UR     YEARS, 


FOR   THE   SALE   OF 


-Photographic   Stock,   Chemicals 

TUBES  AND  APPARATUS, 

P.    SMITH    &   CO., 

No.    121    West    Fifth    Street, 
CINCINNATI,    OHIO. 


A  dvertise  merits. 


zkmwL  FECI  I  so. ' 

WERE  AWARDED  THE 

MEDAL    OF    MERIT 


FOR    THEIR 


Union  Picture  Nails  and  Knobs, 

Grapho-Stereoscopes, 

UNION    FRAMES, 

FbotograpMc  FriiatiEg  Frames^ 

NEGATIVE  BOXES,  &c.', 

AT    THE 

ileal  Oiitiulil  lip©iitl@i$ 

1876. 


SCOVILL  MANUFAOTUEING  CO.,  Agents, 

419  &  421    Broome  Street, 
NEW  YORK. 


Advertisements, 


TRAPP  &  MUNCH'S 


THE   PAPER  OF  THE   DAY. 

Introduced  in  this  country  since  1868,  it  has  become  the  leading 
paper,  and  is  now  better  known  and  more  appreciated  than  any  other 
brand. 

That  this  great  success  is  well  deserved,  and  that  this  paper  is 
superior  to  all  others,  may  be  judged  from  the  fact  that  of  all  of  the 
competitors  of  the  Vienna  Exhibition,  Messrs.  Trapp  &  Munch 
alone  received  the 

for  Albumenized  Paper,  and  also  received  the  only 

Medal  and  Diploma  at  the  Centennial  Exhibition 

at  Philadelphia,  granted  to  any  foreign  exhibitors  of  albumenized 
paper. 

WILLY    WALLACH, 

General  Agent  for  the  United  States, 

NO.  4  BEEKMAN  STEEET  AND  36  PARK  ROW, 

New    Yorlc 


Advertisements. 


ESTABLISHED    1S60. 


HENRY    D.    MARKS, 

DEALER    IN 

PHOTOGRAPHIC  GOODS, 

Over  No.   12  State  Street, 


My  Stock  includes  Apparatus,  Chemicals,  Glass,  Plates, 
Paper,  Card  Stock,  Stereoscopes,  and  a  large  and  desirable 
assortment  of  Frames,  Mats,  and  Passe  Partouts. 


I  make  a  specialty  of 

SILK  VELVET  PASSE  PARTOUTS, 

and  can  show  the  best  variety  of  these  goods  to  be  found 
anywhere. 

Headquarters  for  everything  pertaining  to  Photography. 

Best  Goods,  Lowest  Prices,  and  over  twenty-five  years^ 
experience. 


Advertisements. 


0 

Ho 

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REMINGTON'S 

Breech-Loading  Rifles. 

LONG-RANGE. 

"  Creedioor,"  (as  used  by  tie  Rile  Teams.) 

No.   1 —Pistol-grip-stock,     vernier    and    wind-guage  _j^«e 
sights,  34  inch  barrel,  10  lbs.  weight ,  .$100  00 

No.  2—'  i)oriing—P—G— pattern— 8tock,  vernier  and 

Wind-gauge  sights,  34  inch  barrel,  10  lbs.  v?eight. . .     75  00 

No.  3— Militaiy  —  Stock,    vernier     and    -wind-gauge 

sights,  34  inch  barrel,  10  lbs.  weight 55  00 

Extra — 8ame  as  No.  1,  except  rubber  butt  and  tip,  and 
checked  for- end,  including  spirit  level  and  2  ex. 
disc 125  to 

Superior— Hame  as  extra,  except  selected  curley  pol- 
ished stock 150  00 

MID-RANGE.     "Wimbledon." 

44-77,  45-70  and   :;o-70.   '-^  '"•  =*»  '"• 
No.  O— Sporting  stock,  ordinary  peep  and  globe 

sights $39  00  $41  00 

No.   1— Sporting  stock,  improv'd  peep  and  globe 

sights 44  50    46  50 

No.  2— Si)orting  P  G  pattern  stock,  improved 

I)eep  and  globe  sights 50  00    52  00 

No.  8— Sporting  P  G  pattern  stock,  improved 

peep  and  wind-guage  sights 51  50    53  50 

No.  4— Sportmg  P  G  pattern  stock,  vernier  peep 

and  wind-gauge  sights 60  50    62  50 

No,  S— Sporting  pistol-grip  stock,  vemifer  i)eep 

and  wind-gauge  sights 64  00    66  00 

No.  6— Sporting  pistol-grip  fine  stock,  rubber 

butt  and  tip,  checked  tor-end,  vernier  i)eep 

and  wind-guage  sights 75  00    77  00 

SHORT-RANGE.    '•  Dollymount." 

40-50,  40-70  C  F  ;  46,  44,  38,  R.  F.    •■^«i°-   '-^'p- 

No.  O— Siwrting  stock,  ordinary  peep  and  globe 

sights $87  00  $39  00 

No    1— Sporting  stock,  improved  peep  and  globe 

sights 42  50    44  60 

No   2— Sporting  P  G  pattern  stock,  improved 

I)eep  and  globe  sights 50  00    52  00 

No.  3— Pistol-grip  stock,  improved   peep   and 

globe  sights 54  00    56  60 

No,  4— Pistol-grip  stock,  vernier  peep  and  wind- 
gauge  sights 62  00    64  00 

SPORTING-38, 44,  46  Rim-fire ;  40, 44, 45  and  50  Cen  • 

ter-fire 26  inch,  $32,  28  in.,  $34,  30  in.,  $36,  32  in.,  38  00 

GALLERV— 22,32,  38  Rim-fire $34  and  32  00 

38  Rim-fire,  special 20  00 

MILITARY-U.  S.  model  and  Span- 
ish model $j6  50  $18  50  with  bayonet 

MILITARY— Springfield  model.  13  00    15  00        " 

"  Egyptian  model...  17  00    20  50  with  sabre. 

Civil  Guard 17  00    20  60 

"  Carbine 16  00 

Send  for  illustrated  catalc^rue.    Address, 

E.  REMINGTON  &  SONS, 

P.  O.  Box  3994.  283  BROADWAY. 

Armory,  Ilion,  N.  Y.  New  York. 


Advertisements.  11 


STANDARD  WORKS  ON  CHEMICAL  ANALYSIS, 

PUBLISHED    BY 

D.  VAN  NOSTEAND,  23  Murray  and  27  Warren  Streets. 

Beilstein.  An  Introduction  to  Qualitative  Chemical  Analysis.  By  F. 
Heilstein.  Translated  from  the  Third  German  Edition  by  I.  J. 
Osbun.     i2mo,  cloth $o  75 

Crookes.    Select  Methods  in  Chemical  Analysis  (chiefly  Inorganic). 

,       By  Wni.  Crookes,  F.R.S.     Crown,  8vo,  cloth 625 

^Douglass  &.  Prescott.  Qualitative  Chemical  Analysis.  A  Guide 
in  the  Practical  Study  of  Chemistry,  and  in  the  Work  of  Analysis. 
By  Prof.  S.  H.  Douglass  and  A.  B.  Prescott,  of  the  University  of 
Michigan.     2d  Edition,  revised,  Svo,  cloth 3   50 

Eliot  &  Storer.  A  Compendious  Manual  of  Qualitative  and  Quanti- 
tative Chemical  Analysis.  By  Prof.  Charles  W.  Eliot  and  Prof. 
Frank  H.  Storer.  Revised,  with  co-operation  of  the  authors,  by 
Wm.  Ripley  Nichols.     Fourth  Revised  Edition.     i2mo,  cloth i  00 

Fresenius.    Qualitative  Chemical  Analysis.     By  Dr.  C.  R.  Fresenius, 

8th  English  from  the  13th  German  Edition,  by  A.  Vacher.    Svo,  cloth.     600 

Fresenius.  Quantitative  Chemical  Analysis.  By  Dr.  C.  R.  Fresen- 
ius.    7th  English  Edition.     Vol.  i.     Svo,  cloth 750 

Mott.  The  Chemist's  Manual.  A  Practical  Treatise  on  Chemjstry, 
including  Qualitative  and  Quantitative  Analysis,  etc.,  etc.  By  Dr. 
Henry  A.  Mott,  Jr.     Svo,  cloth \ 6  00 

Naquet.  Legal  Chemistry.  A  Guide  to  the  Detection  of  Poisons, 
Examination  of  Stains,  etc.,  as  applied  to  Chemical  Jurisprudence. 
Translated,  with  Additions  from  the  French  of  A.  Naquet,  by  Dr. 
I.  P.  Buttershall,  and  a  Preface  by  Dr.  C.  F.  Chandler.    i2mo,  cloth     2  00 

Plattner.  Manual  of  Qualitative  and  Quantitative  Analysis  with  the 
Blow-Pipe.  From  the  last  German  "edition,  revised  and  enlarged, 
by  Prof.  Th.  Richter.  Translated  by  Prof.  H.  B.  Cornwall  and 
John  H.  Caswell,  A.M..  Svo,  cloth. . . .' 5  00 

Plympton.  A  System  of  Instruction  in  the  Practical  Use  ol  the  Blow 
Pipe.  Being  a  Graduated  Course  of  Analysis  for  the  Use  of  Students, 
and  all  those  engaged  in  the  Examination  of  Salts  and  Minerals. 
Compiled  and  arranged  by  Prof.  George  W  Plympton.  i2mo,  limp  cl.     i  50 

Prescott.  Outlines  of  Proximate  Organic  Anal}^sis  for  the  Identifica- 
tion, Separation  and  Quantitative  Determination  of  the  more  com- 
monly occurring  Organic  Compounds.  By  Prof.  A.  B.  Prescott. 
i2mo,  cloth I  75 

Prescott.  Chemical  Examinations  of  Alcoholic  Liquors.  A  Manual 
of  the  Constituents  of  the  Distilled  Spirits  and  Fermented  Liquors 
of  Commerce,  and  their  Qualitative  and  Quantitative  Determina- 
tions.    i2mo,  cloth I  50 

Rammelsburg.  Guide  to  a  Course  of  Quantitative  Chemical  Analysis, 
especially  of  Minerals  and  Furnace  Products.  Illustrated  by  Exam- 
ples. By  Dr.C.F.Rammelsburg.  Translated  by  I.Fowler,M.D.  Svo,  cl.     2  25 

Wanklyn.'  Milk  Analysis  :  A  Practical  Treatise  on  the  Examination  of 
Milk  and  its  Derivatives — Cream,  Butter  and  Cheese — by  J.  A. 
Wanklyn.     i2mo,  cloth.  New  York,  1874 100 

Water  Analysis.     4th  Edition,  i2mo,  cloth.     London,  1876 2  50 

Tea,  Coffee'and  Cocoa  :  A  Practical  Treatise  on  the  Analysis  of  Tea, 

Coffee  and  Chocolate.     i2mo,  cloth.     London,  1874 2  50 


12  Advertisements. 


CHARLES  COOPER  &  CO. 

OFFER  AT  WHOLESALE: 

PHOTO.    CHEMICALS, 

STRICTLY    PURE    AND   OF    FULL    WEIGHT; 

CROSS    SWORDS    DRESDEN 

eilUIll   lT4Ftl.   lliSlS, 

'SOLID    GLASS    BATHS, 


ETC 


We  are  the  largest  and  most  reliable  house  for  Refining 
Photographic  Residues. 

CHARLES  COOPER  &  CO., 

MANUFACTURING  CHEMISTS  AND  IMPORTERS, 

191    "Worth    Street, 

NEW    YORK. 


Advertisements.  13 


J.   C.   SOMERVILLE, 

No.  8  South  Fifth  Street, 


DEALER    IN 


Photographic  Materials 

OF    EVERY    DESCRIPTION, 

FRAMES,    MATS,    PICTURE    CORD, 
Albums,  Glass,  &c. 

ST-      XjOXJIS,      ISJSiO. 


Tilford's    Iodized    Collodion, 

Tilford's  Negative  Collodion, 

Tilford's  Silver  Bath  Solution, 
American  Optical  Co.'s  Celebrated 

Camera  Boxes  and  Apparatus, 

Powers  &  VVeightman's  Silver, 

Gold,  Iodides  and  Bromides, 
Voightlander  &  Sons'  Lenses, 

Oval  and  Solid  Oval  (jOld  Frames, 

Oval  and  Square  Solid  Walnut  Frames, 
Oval  and  Square  Imitation  Frames, 

Glass  and  Ferro  Plates, 

Screw  Eyes,  Backing, 

AND  EVERY  WANT  FOR  THE  TRADE. 


14  Advertisements. 


THE  SCIENTIFIC  AMERICAN  REFERENCE  BOOK, 

Price,  Twenty-five  Cents. 

This  is  a  most  useful  little  bound  book  of  150  pages,  comprising,  proba- 
bly, the  most  extensive  variety  of  standard,  practical,  condensed  information 
ever  furnished  to  the  public  for  so  small  a  price.     Contents  : 

1.  The  Last  Census  of  the  United  States  (1870),  by  States,  Territories 
and  Counties,  in  full,  showing  also  the  area  in  square  miles  of  each  State 
and  Territory. 

2.  Table  6f  Occupations. — Showing  the  occupations  of  the  people  of  the 
United  States,  and  the  number  of  persons  engaged  in  each  occupation. 
Compiled  from  the  last  census. 

3.  Table  of  Cities  having  over  10,000  inhabitants.  Compiled  from  the  last 
Census. 

4.  Map  of  the  United  States.     Minature  outline. 

5.  The  United  States  Patent  Laws  (full  text).— Principal  Official  Rules 
for  Procedure  ;  Directions  How  to  obtain  Patents  ;  Costs,  etc.  ;  Forms  for 
Patents  and  Caveats  ;  How  to  Introduce  and  Sell  Inventions  ;  Forms  for 
Assignments  ;  Licenses;  State,  Town,  County,  and  Shop  Rights  ;  General 
Principles  applicable  to  Infringements;  Synopsis  of  the  Patent  Laws  of 
Foreign  Countries  ;  Rights  of  Employers  and  Employees  in  respect  to  In- 
ventions. 

6.  The  Ornamental  Design  Patent  Law  (full  text). — Costs  and  Procedure 
for  securing  Design  Patents  for  Ornamental  Productions  such  as  Designs 
for  Textile  Fabrics,  Patterns  for  Wood  and  Metal  Work,  New  Shapes  and 
Configurations  of  any  article  of  Manufacture,  Print?,  Pictures  and  Orna- 
ments, to  be  printed,  woven,  stamped,  cast,  or  otherwise  applied  upon 
machinery,  tools,  goods,  fabrics,  manufactures. 

7.  The  United  States  Trade-Mark  Law  (full  text).— With  Directions, 
Proceedings  and  Expenses  for  the  Registration  of  Trade  Marks  of  every 
description. 

8.  The  Label  Copyright  Law  (full  text).— With  Directions,  Proceedings 
and  Cost  of  Registering  Labels  for  Goods,  Medicines  and  Merchandise  of 
all  kinds. 

9.  The  General  Copyright  Law  of  the  United  States  (full  text).— With 
Directions  and  Costs  for  Securing  Copyrights  by  Authors  for  Books, 
Pamphlets,  Charts,  Photographs,  Pictures  and  Works  of  Art. 

10.  The  Principal  Mechanical  Movements. — Described  and  illustrated  by 
150  small  diagrams,  of  great  value  to  Inventors  and  Designers  of  Mechan- 
ism, 

11.  The  Steam  Engine. — With  engraving,  showing  all  the  parts,  names, 
etc,  and  a  brief  history  of  the  Invention  and  Progress  of  Steam  Power, 


Advertisements.  15 


12.  Geometry,  as  Applied  to  Practical  Purposes.     With  illustrations. 

13.  Horse  Power. — Simple  Rules  for  Calculating  the  Horse  Power  of  Steam 
Engines  and  Streams  of  Water. 

14.  Knots. — Presenting  engravings  of  4S  different  kinds  of  Rope  Knots, 
with  explanations  as  to  tying. 

15.  Tables  of  Weights  and  Measures. — Troy,  Apothecaries',  Avoirdupois, 
French  Weights  ;  U.  S.  Standard;  Dry  Measure;  Land  Measure;  Cubic 
Measure  ;  Liquid  Measure  ;  French  Square  Measure  ;  French  Cubic,  or 
Solid  Measure  ;  Measuring  Land  by  Weight ;  Engraving  of  a  section  of 
English  and  French  rule,  of  equal  length. 

16.  Valuable  Tables  :  (i)  Velocity  and  Force  of  the  Wind.  (2)  Specific 
Gravity  and  Weight  per  Cubic  foot  and  Cubic  inch,  of  the  princip'al  sub- 
stances used  in  the  Arts.  (3)  Heat  conducting  Power  of  various  Metals 
and  other  Solids  and  Liquids  (4)  Table  of  the  Mineral  Constituents  ab- 
sorbed or  removed  from  the  Soil,  per  acre,  by  different  crops.  (5)  Table 
of  Steam  Pressures  and  Temperatures.  (6)  Table  of  the  Effects  of  Heat 
upon  various  bodies,  melting-points,  etc. 

17.  Medallion  Portraits  of  Distinguished  American  Inventors,  with  bio- 
graphy in  brief,  and  engravings  of  their  inventions,  viz. :  Franklin,  Fulton, 
Whitney,  Wood,  McCormick,  Blanchard,  Winans,  Morse,  Goodyear,  Howe, 
Lyle,  Eads. 

18.  Engravings  of  Capitol,  Washington,  with  brief  history,  dimensions, 
cost,  etc.  ;  United  States  Patent  Office,  interior  and  exterior  views,  dimen- 
sions and  description  ;  Scientific  American  Buildings,  New  York  and 
Washington. 

19.  Miscellaneous  Information. — Force  of  Expansion  by  Heat;  Small 
Steamboats,  proper  dimensions  of  Engines,  Boilers,  Propellers,  Boats  ; 
Incubation,  Temperature  of;  To  Make  Tracing  Paper;  Constituents  of 
various  substances;  Friction,  how  produced,  and  Rules  for  Calculation  ; 
Specific  Heat  Explained  ;  Specific  Gravity  of  Liquids,  Solids,  Air  and 
Gases;  Gunpowder — Pressure,  Heat  and  Horse-Power  of;  Copying  Ink, 
to  Make  ;  Heat,  its  mechanical  equivalent  explained  ;  Molecules  of  Mat- 
ter, size  and  motion  explained  ;  Lightning  and  Lightning  Rods — valuable 
information  ;  Value  of  Drainage  Explained  ;  Amount  of  Power  at  pre- 
sent yielded  from  Coal  by  best  Engines  ;  Sound — its  velocity  and  action  ; 
Liquid  Glues,  Recipes  ;  Value  of  Brains  ;  Properties  of  Charcoal  ;  Height 
of  Waves  ;  Speed  of  Electric  Spark,  etc.  ;  Plain  Directions,  with  Engrav- 
ings, showing  how  any  person  can  make  Electro  Magnets  and  Electric 
Batteries  a^a  cost  of  a  few  cents  ;  Valuable  Recipes. 

The  Scientific  American  Reference  Book,  price  only  25  cents,  may  be  had  of 
News  Agents  in  all  parts  of  the  countrj-,  and  of  the  undersigned.  Sent  by 
mail  on  receipt  of  the  price.     Address 

iv^xjiisrisr  <sc  co., 

37    Park  Row,  New  York, 


16 


Advertisements. 


MAMMOTH 


stocik:    hiotjse. 


EIOE  &  THOMPSON, 

Manufacturers 

AND 

WHOLESALE  DEALERS 

IN 

Photographic 

Materials, 

MOULDINGS, 
Frames,    Mirrors,    Pictures, 

GLASS, 

CORDS,TASSELS,CHROMOS, 

Mirror  Plates,  Albums,  Fancy  Goods,  Etc., 

CHICAGO,    ILL. 


Advertisements.  1 7 


t]h:e 


American  Optical  Company 

Manufactures  the  Most  Perfect 

PHOTOGRAPHIC  APPARATUS 

YET    INTRODUCED    TO    THE     PROFESSION    IN     EURORE    OR 

AMERICA. 

THIS  FACT  IS  UNIVERSALLY  CONCEDED. 

THEIR  APPARATUS 

RECEIVED 

THE  HIGHEST  AWARD 

AT  THE 

Vienna  Exposition,-        -        1873, 
Brussels  "  -        1874, 

Centennial      "  -        1876, 

UPON    WHI^II    OCCASIONS    IT    WAS    PLACED    IN' COM- 
PETITION   WITH    THE    BEST    APPARATUSES 
FROM  THE  BEST  MAKERS  OF 

ENaLAlB.  GEMMAMY,  FMAICE  k  AfflEMICA. 


For  Sale  by  all  Dealers  in  Photographic  Stock  throughout  Europe  and  the 
United  States  and  Oanadas, 


18 


Advertisements. 


THE  AMERICAN  OPTICAL  CO.>S 

IMPROVED   VIEW    CAMERAS, 


WITH  CONE   BELLOWS, 


are  models  of  lightness,  strength,  compactness  and  durability. 


THEIR 


POCKET   CAMERAS 


are  the  simplest,  most  compact  and  portable  apparatuses  ever  made. 


Advertisements.  Id  1 


FRED.   MULLETT, 

(Successor  to  G.  D.  Wakely,) 
DEALER  IN 

PHOTOGRAPHIC    MATERIALS, 
Frames,  Glass,  Picture  Cord,  Etc., 

518    AVALNUT    STREET, 

KANSAS  CITY,  MO. 


THE    Gr-RV^ATV 

National  Photographic  Emporium 

46    NORTH    CHARLES    STREET, 
Baltimore,  Md. 

The  most  complete  and  best  regulated  Stock   house  in  America. 

EVEKYTHING  PERTAINING  TO  PHOTOGRAPHY 

at  the  lowest  market  rates. 


Send  for  a  copy  of 

THE   PHOTOGRAPHER'S   FRIEND, 

Fiftli    Edition. 

R.   WALZL. 

Sent  gratis  upon  application. 


30  Advertisement. 


CENTENiriAL 
PHOTOaRAPHIC    COMPAIIY, 

International  Exhibition  G-ronnds. 
BELMONT  AVENUE, 

View^     of    \k\^     der\teni\ikl     5<xl:\ibitioi\, 
EXTERIORS  AND  INTERIORS, 

FOR   THE 

Graphoseope,     Stereoscope, 

PORTFOLIO, 
Magic  Lantern  and  Card  Holder, 

PROPRIETORS. 

ALSO     A     COMPLETE     ASSORTMENT     OF 
JStEREOSCOPES,         pRAPHOSCOPES,         txC. 

KILBUEN'S  WHITE    MOUNTAIN    STEEEO-PIOTUEES, 

AND   OTHER  AMERICAN   VIEWS. 


Advertisements. 


21 


MANUFACTURER  OF 


JVo.    182   cjsjvtSI:e  st^ejet, 

(UP  STAIRS,) 


Corner  Hester  Street, 


NEW  YORK. 


"V7".     F.      j^SHE, 


And    manufacturer    of 


Photographic  Backgrounds, 

INTERIOR,  LANDSCAPE,  PLAIN,  REMBRANDT, 
AND  SHADED. 

SLIPS  AND  ACCESSORIES  OF  ALL  KINDS 
Blue  FrostiMg  tor  SkyligMs,  etc. 

SertcL   for    Samples    cltxcL    ^rtce    Ltst. 


OFFICE  AND  SHOW  ROOMS: 

No.   106   Bleecker  Street,  corner  of  Greene, 

NEW  YORK. 


22  V         Advertisements. 


ESTABLISHED    1S03. 


S  O  O  ^IL  L 

Manufacturing    Company, 

MANUFACTURERS  OF  AND  DEALERS  IN 

PHOTOGRAPHIC  GOODS 

OF   EVERY   DESCRIPTION. 


STOCK  DEALERS,  PHOTOGEAPHERS 

AND 

SUPPLIED. 


MANUFACTORIES; 

Waterbury,  Ct. ;  New  Haven,  Ct. ;  New  York. 


WAREHOUSE: 

419   and  431    Broome   Street, 


Advertisements.  23 

THE   "PEERLESS" 

IS  THE  BEST  AND  THE  CHEAPEST 

PORTRAIT  LENS 

Il:T    XJSE. 

Highest  Testimonials  from  the  best  Photographers 
in  the  Country. 

EVERY  LENS  WARRANTED-SATISFACTION  GUARANTEED. 


MORRISON^S 

Wide  Angle  View  Lenses. 

(PATENTED  MAY  21st,  1872.) 

Thdj  ernhrace  an  angle  of  fully  100  degrees,  work 
more  rapidly  than  any  other  Wide  Angle  Lens  made,  and 
are  absolutely  rectilinear. 


MORRISON'S 

NEW  RAPID  COPYING  LENS, 

FOR 

COPYINa  OUTDOOR  GROUPS  AND  INSTANTANEOUS  VIEWS. 

These  JJenses  work  with  full  aperture  for  Groups,  and 
will  copy  with  absolute  correctness  Architectural  Drawings^ 
Charts,  Engravings,  §-c.,  ^c. 

FOE  SALE  BY  ALL  DEALEES. 


Advertisements. 


0«^p  Afe|I 


For  ExMDiting 
Plotograpiic  Portraits, 
Landscapes,  and  otler 
Pictorial  Works  of  Art, 
eitner  Single  or  Stereo- 
scopic Views. 

Tnese  Instruments  are 
fnrnisnedwitn  tie  finest 
Imporied  Lenses,  and  are 
snperior  in  pality  and 
Material  to  tliose  dl 
any  otlier  make  in  tie 
market. 


Nos.  0,  1  and  2  are  made  of  Black  "Walnut  and  finished  in  Oil.— Nos.  2i,  3  and  4  are  made 
of  Black  Walnut,  are  heavier  than  Nos.  0,  1  and  2,  and  are  handsomely  polished.— No.  5  is  made 
partly  of  solid  Rosewood  and  is  partly  veneered  in  Rosewood.  The  box  is  lined  with  Curled 
Maple,  and  the  whole  polished.— No.  6,  Black  Walnut,  polished,  eleg:intly  trimmed  and  fin- 
ished.—No.  7  is  made  like  No.  5,  except  that  it  has  a  four  inch  lens,  and  is  exquisitely  finished 
in  French  polish.— No.  8  is  made  ot  solid  Walnut,  finished  and  trimmed  like  No.  9.— No.  9,  ele- 
gantly made  of  solid  Rosewood,  superbly  finished  in  French  polish  and  richly  trimmed  in  bur- 
nished nickel.  The  Grapho.  lens  slides  vertically  on  polished  nickel  rods,  capped  with  ivory. 
The  picture  rest  is  of  exquisite  open  work  design,  and  is  supplied  with  ground-glass  for  transpa- 
rent stereoscopic  pictures. 


SCOVILL   MANUFACTURING-  COMPANT, 
419  &  421  Broome  St.,  New  York. 


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