belief　that　it　would　also　improve　and　ensure　its　lasting
  qualities；　but　latterly　more　often　to　cheapen　the
  cost　of　its　manufacture。　Reference　has　been　made
  to　a　large　variety　of　these　substances　used　for　this
  purpose　and　the　story　told　of　the　effect　of　the　test　of
  time　upon　them　as　indicative　of　their　supposed　value。
  Attention　has　also　been　directed　to　the　discovery
  during　the　nineteenth　century　of　the　colors　which
  owe　their　origin　to　by…products　of　coal　tar。
  Generically　these　colors　are　classified　as　〃anilines。〃
  They　have　worked　a　revolution　in　all　the　arts　in
  which　colors　are　used。　Employed　without　a　mordant；
  with　few　exceptions；　they　are　measurably　affected　by
  both　light；　heat；　moisture；　or　other　changes　and　as
  made　into　inks　are　never　permanent。　Hence　they
  should　not　be　used　for　records；　because　if　obliterated
  from　any　cause　whatever；　there　are　no　known　means
  to　render　them　again　legible。
  The　origin　and　history　of　the　〃anilines〃　are
  known。　Viewed　from　an　ink　standpoint　they　are　of
  vast　interest。　So　extended　in　number　are　the　〃anilines〃
  （they　run　into　the　thousands）　that　they　include
  every　shade　of　black　and　all　possible　tints　or　hues　of
  the　colors　of　the　rainbow。
  The　chronological　history　of　such　of　these　artificial
  colors　which　appertain　to　ink　or　its　manufacture　is
  important　as　locating　the　dates　of　their　invention
  and　commercial　use。
  The　first　discovery　of　〃aniline〃　is　credited　to
  Helot　in　1750。　In　1825　Faraday　in　rectifying　naphtha
  discovered　benzole；　which　by　the　action　of　strong
  nitric　acid　be　converted　into　nitro…benzole；　and　this
  latter；　when　agitated　with　water；　acetic　acid　and　iron
  filings　produced　aniline。　Unverdorben　in　1826　discovered
  an　analogous　material　in　products　obtained
  by　the　destructive　distillation　of　indigo。　Runge　in
  1834　claims　to　have　detected　it　in　coal　tar　and　called
  it　kyanol；　which　after　oxidation　became　an　insoluble
  black　pigment　and　known　as　aniline　black。　It　could
  not；　however；　be　used　as　an　ink。　Zinan　in　1840；
  experimenting　along　the　same　lines；　produced　another
  compound　terming　it　benzidam。　Fritsche　in　the　same
  year　by　the　distillation　of　indigo　with　caustic　potash
  developed　a　product　which　he　also　called　aniline；　the
  name　being　derived　from　the　Portuguese　word　anil；
  meaning　indigo。　Shortly　afterwards　A。　W。　Hoffman
  established　the　identity　of　these　substances。
  Aniline　when　pure　is　a　colorless　liquid；　possessing
  a　rather　ammoniacal　odor。　It　soon　becomes　yellow
  and　yellow…brown　under　the　influence　of　light　and　air。
  It　does　not　affect　litmus　paper。
  In　1856　Perkins　accidentally　discovered　the　violet
  dye　called　mauve；　which　acquired　considerable　commercial
  importance　besides　its　utility　for　ink　purposes。
  Nicholson　in　1862　succeeded　in　producing　the　first
  of　the　soluble　blue　anilines。
  The　discovery　of　induline；　one　of　the　modifications
  of　aniline　black；　was　made　known　in　1864。
  Nigrosine；　produced　by　the　action　of　concentrated
  sulphuric　acid　on　the　insoluble　indulines；　was　discovered
  in　1868。
  The　soluble　indulines　and　nigrosines　differentiate　in
  appearance；　the　first　a　bronzy　powder　and　the　latter　a
  black　lustrous　powder。　When　made　into　ink　they
  possess　about　equal　color　values。
  In　1870　the　German　chemists；　Graebe　and　Liebermann；
  announced　that　they　had　succeeded　in　producing
  artificial　alizarin；the　coloring　matter　of　the
  madder　root。　Commercial　value　was　not　given　to
  this　discovery　until　it　was　put　on　the　market　in　1873；
  although　it　did　not　meet　all　the　requirements。
  Springmuhl　in　1873　obtained　an　accessory　product
  in　the　artificial　manufacture　of　alizarin　out　of　anthracene；
  from　which　a　beautiful　blue　was　made；　superior
  in　many　respect　to　the　aniline　blues。　It　differed　from
  aniline　in　having　the　same　color　in　solution。　Alkalis
  destroyed　the　color　but　acids　restored　it。　The　process
  was　kept　a　secret　for　a　long　time。　This　product　was
  originally　sold　as　high　as　1；500　for　a　single　pound。
  Caro；　a　German　chemist；　invented　in　1874　the　red
  color　known　as　eosine；　which　was　brought　to　this
  country　in　the　following　year　and　sold　for　125　per
  pound。　Its　color　is　destroyed　by　acids。
  Orchil　or　archil　（the　red　color）　was　discovered　in
  1879。　The　commercial　use　of　the　so…called　〃orchil
  substitutes〃　（purples）　began；　however；　in　the　years
  1885　and　1887。
  Artificial　indigo；　as　the　result　of　many　years　of
  experimenting；　came　into　commercial　use　under　the
  name　of　〃indigo　pure〃　only　in　1897。　It　had　previously
  been　produced　synthetically　in　a　variety　of
  ways；　but　the　cost　of　the　production　was　far　above
  that　of　the　natural　product。　Baeyer　and　Emmerling
  in　1870；　Suida　in　1878；　Baeyer　in　1878；　Baeyer　and
  Drewsen　in　1882；　and　Heumann　in　1890；　can　be　said
  to　have　been　the　pioneers　in　the　production　of　artificial
  indigo。
  The　intensity　of　some　of　the　aniline　colors　may　be
  indicated　by　the　fact　that　a　single　grain　of　eosine　in
  ten　millions　of　water　exhibits　a　definite　rose…pink
  color。
  It　is　asserted　that　in　the　last　three　years　many
  improvements　have　been　made　in　the　permanent　qualities
  of　some　of　the　soluble　anilines；　but　no　material
  which　is　soluble　in　plain　water　should　ever　be　employed
  as　an　ink　for　record　purposes。
  Preceding　the　discovery　of　the　〃anilines；〃　as　already
  related；　other　substances　had　been　employed
  for　〃added〃　color　in　the　admixture　of　ink；　principally
  madder；　Brazil　wood；　indigo；　and　logwood。
  Only　a　casual　reference　has　heretofore　been　made
  to　Brazil　wood　and　logwood。
  Brazil　wood；　also　called　peach　wood；　is　imported
  from　Brazil。　Its　employment　as　a　dyestuff　is　known
  to　be　of　great　antiquity；　antedating　considerably　the
  discovery　of　South　America。　Bancroft　states；　〃The
  name　'Brazil'　was　given　to　the　country　on　account
  of　the　extensive　forests　of　the　already　well…known
  'Brazil　wood；'　which　was　found　by　its　Portuguese
  discoverers。　The　dyestuff　thus　gave　its　name　to　the
  country　from　which　it　was　afterwards　principally
  obtained。　The　word　'Brazil'　appears　to　have　been
  originally　used　to　designate　a　bright　red　or　flame
  color。　Thus　in　a　contract　between　the　cities　of　Bologna
  and　Ferrara；　in　1194；　the　dyestuff　kermez　is
  referred　to　as　grana　de　Brazile　and　Brazil　wood；　both
  dyestuffs　at　that　time　being　obtained　from　India。〃
  For　〃added〃　color　to　ink　and　alone　it　was　much
  used　in　the　seventeenth　and　eighteenth　centuries。
  Logwood；　employed　more　extensively　for　〃added〃
  color　than　any　other　color　compound；　was　introduced
  into　Europe　by　the　Spaniards；　A。　D。　1502。　In　England
  it　does　not　appear　to　have　been　much　used　until
  about　1575。　In　1581　the　Parliament　prohibited　its
  use　〃because　the　colours　produced　from　it　were　of　a
  fugacious　character。〃　Its　use　was　legalized　in　1673
  by　an　act；　the　preamble　of　which　reads；　〃The　ingenious
  industry　of　modern　times　hath　taught　the
  dyers　of　England　the　art　of　fixing；　the　colours　made
  of　logwood；　alias　blackwood；　so　as　that；　by　experience；
  they　are　found　as　lasting　as　the　colours　made
  with　any　sort　of　dyeing　wood　whatever。〃　It　is　obtained
  principally　from　the　Campeachy　tree；　which
  grows　in　the　West　Indies　and　South　America。
  The　practical　utility　of　logwood　as　the　base　for　an
  ink　was　a　discovery　of　Runge　in　1848；　who　found
  that　a　dilute　solution　of　its　coloring　matter；　to　which
  had　been　added　a　small　quantity　of　neutral　chromate
  of　potassium；　produced　a　deep　black　liquid　which　apparently
  remained　clear　and　did　not　deposit　any　sediment。
  This　composition　became　very　popular　on
  account　of　its　cheapness　and　dark　purple　color。　It
  is　of　a　fugitive　character；　though；　and　has　passed　almost
  entirely　out　of　commercial　use。
  CHAPTER　XXI。
  ANCIENT　AND　MODERN　INK　RECEIPTS。
  〃INDIAN〃　INKSPANISH　LICORICEBITUMENCARBON
  FROM　PETROLEUMPROCESS　TO　OBTAIN　GALLIC
  ACIDEFFECT　OF　SUGAR　IN　INKDARK　COLORED
  GALLS　BEST　FOR　INK　MAKINGSUBSTITUTES　FOR
  GALLSRELATIVE　PROPORTIONS　OF　IRON　AND
  GALLSANECDOTE　OF　PROFESSOR　TRIALL
  ESTIMATION　OF　SULPHATE　OF　COPPERQUAINT　INK
  RECIPERIBAUCOURT'S　INKHORSELEY'S　INK
  ELSNER'S　INDELIBLE　MARKING　INKBLACK　INK　FOR
  COMMON　AND　COPYING　USESCOMMON　BLACK
  INKSHINING　BLACK　INKPROCESS　FOR　〃BEST〃
  INKINDELIBLE　BLACK　INK　WITHOUT　GALLS　OR
  IRONINK　POWDERSTEEL　PEN　INKSOME　EARLY
  LITERATURE　OF　THE　COAL　TAR　PRODUCTSINK　PLANT
  OF　NEW　GRANADA〃IMPERISHABLE〃　INKFIRE…
  PROOF　INK〃INERADICABLE〃　INKEXCHEQUER
  INK〃PERMANENT〃　RED　INKSUBSTITUTE　FOR　〃INDIAN〃
  INKTO　PREVENT　INK　FREEZINGBACTERIA
  IN　INKGOLD　AND　OTHER　INKS　USED　FOR　ILLUMlNATING。
  INNUMERABLE　receipts　and　directions　for　making
  inks　of　every　kind；　color　and　quality　are　to　be　found
  distributed　in　books　more　or　less　devoted　to　such　subjects；
  in　the　encyclopaedias；　chemistries；　and　other　scientific
  publications。　If　assembled　together　they　would
  occupy　hundreds　of　pages。　Those　cited　are　exemplars
  indicating　the　trend　of　ideas　belonging　to