No. 25. THE PHOTOGRAPHIC NEGATIVE.
A Practical Guide to the Preparation of Sensitive Surfaces by the Calotype, Albumen, Collodion, and Gelatine Processes, on Glass and Paper, with Supplementary Chapter on Development, etc., by the Rev. W. H. Burbank. Cloth bound. Reduced from $1.50 to 1 00

No. 26. THE PHOTOGRAPHIC INSTRUCTOR FOR THE PROFESSIONAL AND AMATEUR.
Being the comprehensive series of Practical Lessons issued to the Students of the Chautauqua School of Photography. Revised and enlarged. Edited by W. I. Lincoln Adams, with an Appendix by Prof. Chas. Ehrmann. (Fourth Edition, enlarged and revised.) Paper covers. 1 00
Library Edition. 1 50

No. 27. LETTERS ON LANDSCAPE PHOTOGRAPHY.
By H. P. Robinson. Finely illustrated from the author's own photographs and containing a Photogravure frontispiece of the author. Cloth bound. 1 50

No. 29. THE PROCESSES OF PURE PHOTOGRAPHY.
By W. K. Burton and Andrew Pringle. A standard work, very complete and freely illustrated. Price, in paper covers, $2 00. Library Ed. 2 50

No. 30. PICTORIAL EFFECT IN PHOTOGRAPHY.
By H. P. Robinson. A new edition. Illustrated. Mr. Robinson's first and best work. Cloth bound. 1 50

No. 32. PRACTICAL PHOTO-MICROGRAPHY.
By Andrew Pringle. Fully illustrated. Cloth bound. 2 50

No. 33. THE AMERICAN ANNUAL OF PHOTOGRAPHY AND PHOTOGRAPHIC TIMES ALMANAC FOR 1890.
Paper cover (by mail, 14 cents additional). 50
Library Edition (by mail, 14 cents additional). 1 00

No. 34. THE OPTICAL LANTERN.
Illustrated. By Andrew Pringle. Paper covers, $1.00.
Cloth bound. 1 50

No. 35. LANTERN SLIDES BY PHOTOGRAPHIC METHODS.
By Andrew Pringle. Paper covers 75 cents. Cloth bound. 1 25

No. 36. THE AMERICAN ANNUAL OF PHOTOGRAPHY AND PHOTOGRAPHIC TIMES ALMANAC FOR 1891.
Paper covers (by mail, 15 cents additional). 50
Library Edition (by mail, 15 cents additional). 1 00
Cyclopædic Index for 1891 Annual. 10