—— microscopic pictures, 507. 556.
—— Newton's process, 140. 163. 187. 219. 245. 294. 338.
—— Pollock's directions for obtaining positives, 581.
—— portraits of criminals, 506.
—— positives, 533. 581.
—— processes upon paper, 20. 71.
—— pyrogallic acid, 70. 117. 266.
—— sealing-wax for baths, 314.
—— sensitive paper, 48.
—— Sisson's new developing fluid, 534.