The chronological record of discoveries, inventions, appliances, and publications connected with the art will, it is hoped, be received and considered as a useful and interesting table of reference; while the reminiscences, extending over forty years of unbroken contact with every phase of photography, and some of its pioneers, will form a vital link between the long past and immediate present, which may awaken pleasing recollections in some, and give encouragement to others to enter the field of experiment, and endeavour to continue the work of evolution. At page 10 it is stated, on the authority of the late Robert Hunt, that some of Niépce's early pictures may be seen at the British Museum. That was so, but unfortunately it is not so now. On making application, very recently, to examine these pictures, I ascertained that they were never placed in the care of the curator of the British Museum, but were the private property of the late Dr. Robert Brown, who left them to his colleague, John Joseph Bennett, and that at the latter's death they passed into the possession of his widow. I wrote to the lady making enquiries about them, but have not been able to trace them further; there are, however, two very interesting examples of Niépce's heliographs, and one photo-etched plate and print, lent by Mr. H. P. Robinson, on view at South Kensington, in the Western Gallery of the Science Collection. For the portrait of Thomas Wedgwood, I am indebted to Mr. Godfrey Wedgwood; for that of Joseph Nicéphore Niépce, to the Mayor of Chalons-sur-Saône; for the Rev. J. B. Reade's, to Mr. Fox; for Sir John Herschel's, to Mr. H. H. Cameron; for John Frederick Goddard's, to Dr. Jabez Hogg; and for Frederick Scott Archer's, to Mr. Alfred Cade; and to all those gentlemen I tender my most grateful acknowledgments. Also to the Autotype Company, for their care and attention in carrying out my wishes in the reproduction of all the illustrations by their beautiful Collotype Process. JOHN WERGE. _London, June, 1890._ CONTENTS. INTRODUCTION 1 FIRST PERIOD. The Dark Ages 3 SECOND PERIOD. Publicity and Progress 27 THIRD PERIOD. Collodion Triumphant 58 FOURTH PERIOD. Gelatine Successful 95 CHRONOLOGICAL RECORD. Inventions, Discoveries, etc. 126 CONTRIBUTIONS TO PHOTOGRAPHIC LITERATURE. 140 LIST OF ILLUSTRATIONS. Frontispiece Portrait of Thomas Wedgwood. " Portrait of Joseph Nicéphore Niépce. " Portrait of Rev. J. B. Reade. " Portrait of Henry Fox Talbot. " Portrait of Sir John Herschel. 27 Portrait of L. J. M. Daguerre.