For many years subsequent to the discovery of the process of Photographic Printing by Mr. Fox Talbot, it was not generally known that pictures so produced were easily susceptible of injury from various causes, and in particular from traces of the _fixing-agent_ remaining in the paper. Hence, due care not being taken in the proper cleansing and preservation of the proofs, the majority of them faded. This matter became at last one of such importance that the Council of the Photographic Society decided upon forming a Committee for the purpose of examining the subject. The Author was honoured by being placed upon this Committee, and the researches of which an abstract has been given in the previous Section, were undertaken at the request of the Society. The present Section is intended to explain practically and in a concise manner the causes of the fading of Photographic Prints, and the precautions which should be taken to ensure their permanency. The chemistry of the subject having been fully explained in the last Section, it will suffice to refer the reader to its pages for more detailed information. _Historical evidence of the permanence of Photographs._--It is a point of interest to collect information as to the existence of old Photographs which have remained many years unchanged. There are numerous instances of Positives printed more than ten years ago, which have not perceptibly altered up to the present time. These prints are mostly on plain paper, Albumen not having come into use at so early a date. The general impression of practical operators however is, that fading has occurred less frequently since the introduction of Albuminized paper. Positives printed by development on paper prepared by Talbot's method seem as a rule to have stood remarkably well, and instances of Talbotype Negatives having faded are rare. Of the prints which have proved to be permanent, some are red or brown in colour, but many, being of a dark or purple shade, have evidently been toned, although not with Gold, the use of which was unknown to the earlier Photographers. It is plain from data thus collected, that Photographs do not necessarily fade by time; and the fact that in one and the same portfolio are constantly seen prints which appear permanent, and others in an advanced state of change, cannot but lead to the inference that the main causes of deterioration are intrinsic, depending upon some injurious matters left in the paper; which is confirmed by experiment. _Causes of fading._--The Author believes that the fading of Photographic Prints may almost invariably be referred to one or other of the following conditions:--