Anthony's Patent Perfect Dry Plate-holder
BEST IN THE WORLD!

E. & H. T. ANTHONY & CO. 591 B'way, NEW YORK.

[FOOTNOTES]

  1. [Footnote [1]
  2. Such things as test-tubes should be found in every photographer's work room; they cost little, and are always useful for working solutions. The sizes recommended are 3/8-inch, 1/2-inch, and 1-inch diameter. A dozen of each will not be out of the way.
  3. [Footnote [2]
  4. Sodium Chloride
  5. and
  6. Silver Nitrate
  7. form
  8. Silver Chloride
  9. and
  10. Sodium Nitrate.
  11. NaCl
  12. +
  13. AgNO3
  14. =
  15. AgCl
  16. +
  17. NaNO3
  18. [Footnote [3]
  19. Chlorine
  20. and
  21. Potassium Nitrite
  22. and
  23. Water
  24. give
  25. Hydrochloric Acid
  26. and
  27. Potassium Nitrate
  28. 2Cl
  29. +
  30. KNO2
  31. +
  32. H2O
  33. =
  34. 2HCl
  35. +
  36. KNO3
  37. and
  38. Chlorine,
  39. Silver Nitrate,
  40. and
  41. Water
  42. give
  43. Silver Chloride,
  44. Hydrochlorous Acid
  45. and
  46. Nitric Acid.
  47. 2Cl
  48. AgNO3
  49. +
  50. H2O
  51. =
  52. AgCl
  53. HClO
  54. +
  55. HNO3
  56. [Footnote [4]
  57. With the former we have this action—
  58. Silver Chloride
  59. gives
  60. Silver Sub-chloride
  61. and
  62. Liberated Chloride.
  63. Ag2Cl2
  64. =
  65. Ag2Cl
  66. +
  67. Cl
  68. With the latter the silver in combination with the organic matter, which is in a state of oxide, is probably reduced to the state of sub-oxide.
  69. [Footnote [5]
  70. Sulphuretted hydrogen may be prepared by pouring dilute sulphuric acid on ferric sulphide. The chloride or the silver compound, when damped, may be held over it, taking care that no liquid is spirted up on to it.
  71. [Footnote [6]
  72. Those who prepare collodio-albumen plates will find the upward filtration arrangement of immense value, as bubbles are unknown by it.
  73. [Footnote [7]
  74. If bubbles are seen, they must be broken, and the sheet floated again for another minute.
  75. [Footnote [8]
  76. The drainings are added to the next batch of albumen which is prepared.
  77. [Footnote [9]
  78. "Instruction in Photography," 4th edition, page 121.
  79. [Footnote [10]
  80. Chlorine
  81. and
  82. Water
  83. give
  84. Hydrochloric acid
  85. and
  86. Oxygen.
  87. Cl
  88. +
  89. H2O
  90. =
  91. HCl
  92. +
  93. O
  94. [Footnote [11]
  95. Nitric Acid
  96. and
  97. Silver Carbonate
  98. give
  99. Silver Nitrate
  100. and
  101. Carbonic Acid
  102. and
  103. Water.
  104. 2HNO3
  105. +
  106. Ag2CO3
  107. =
  108. 2AgNO3
  109. +
  110. CO2
  111. +
  112. H2O
  113. [Footnote [12]
  114. Silver Nitrate
  115. and
  116. Aluminium Sulphate (Alum)
  117. give
  118. Silver Sulphate
  119. and
  120. Aluminium Nitrate.
  121. 6AgNO3
  122. +
  123. Al2(SO4)3
  124. =
  125. 3(Ag2SO4)
  126. +
  127. 2Al(NO2)3
  128. [Footnote [13]
  129. Silver Nitrate
  130. and
  131. Hydrochloric Acid
  132. give
  133. Silver Chloride
  134. and
  135. Nitric Acid.
  136. AgNO3
  137. +
  138. HCl
  139. =
  140. AgCl
  141. +
  142. HNO3
  143. [Footnote [14]
  144. Suppose it is salted with ammonium chloride, we have—
  145. Ammonium Chloride
  146. and
  147. Silver Nitrate
  148. give
  149. Ammonium Nitrate
  150. and
  151. Silver Chloride.
  152. NH4Cl
  153. +
  154. AgNO3
  155. =
  156. NH4NO3
  157. +
  158. AgCl
  159. [Footnote [15]
  160. Several other methods are given in "Instruction in Photography," in the Appendix.
  161. [Footnote [16]
  162. One part of nitric acid to 4 parts of water.
  163. [Footnote [17]
  164. The shutter may be made of American leather, covered over with one quarter-inch strips of oak or well-seasoned pine. The shutter should fit into a groove formed along the sides and bottom of the front of the cupboard.
  165. [Footnote [18]
  166. In [fig. 18] the fastening for only one of the pressure-bars is given, to avoid complication.
  167. [Footnote [19]
  168. See "Instruction in Photography" (page 67), fourth edition.
  169. [Footnote [20]
  170. For this reason, amongst others, it is desirable that photographers should use glass for their negatives which is at least tolerably flat.
  171. [Footnote [21]
  172. See "Pictorial Effect in Photography" (Piper and Carter).
  173. [Footnote [22]
  174. Hydrofluoric acid is always supplied by chemists in gutta-percha bottles, as it attacks glass. A spare gutta-percha bottle can easily be procured.
  175. [Footnote [23]
  176. This calculation is near enough for our purpose. There are certain niceties which might be introduced, such as the "critical angle of the glass."
  177. [Footnote [24]
  178. The boxes in which children's puzzles are often packed will give an idea of what is meant.
  179. [Footnote [25]
  180. Silver subchloride
  181. and
  182. gold trichloride
  183. give
  184. silver chloride
  185. and
  186. gold.
  187. 3Ag2Cl
  188. +
  189. AuCl3
  190. =
  191. 6AgCl
  192. +
  193. Au
  194. [Footnote [26]
  195. "Instruction in Photography," 4th edition.
  196. [Footnote [27]
  197. "Instruction in Photography," 4th edition.
  198. [Footnote [28]
  199. Or ten minims of ammonium lactate.
  200. [Footnote [29]
  201. See Mr. W. Brooks' article in Photographic Almanac, 1881.
  202. [Footnote [30]
  203. The crucible should be of Stourbridge clay.
Sodium ChlorideandSilver NitrateformSilver ChlorideandSodium Nitrate.
NaCl+AgNO3=AgCl+NaNO3
ChlorineandPotassium NitriteandWatergiveHydrochloric AcidandPotassium Nitrate
2Cl+KNO2+H2O=2HCl+KNO3
Chlorine,Silver Nitrate,andWatergiveSilver Chloride,Hydrochlorous AcidandNitric Acid.
2ClAgNO3+H2O=AgClHClO+HNO3
Silver ChloridegivesSilver Sub-chlorideandLiberated Chloride.
Ag2Cl2=Ag2Cl+Cl
ChlorineandWater giveHydrochloric acidandOxygen.
Cl+H2O=HCl+O