GEORGE THOMPSON.—1. Although we do not esteem the maker of your lens as one of the best, he has, for all that, a fair reputation in his own country; and we know that he has made some good lenses. We have not, however, heard of him for several years past.—2. Dr. Monckhoven is a dealer in apparatus—not a manufacturer of lenses.
F. C. S.—Ideas often run in parallel grooves. For several weeks past we have been using our note-book very freely in the collection of materials for such a series of articles as that suggested by you. Some of the information required to render the series of the greatest possible value is only procurable with much difficulty and at no little expense; still, such progress in the compilation has been made as will warrant the indulgence of a hope that we may be able to introduce the subject at no distant date.
ERRATUM.—In Mr. Coote’s article in our last number, page 38, second column, eleventh line from top, for “you are apt to hurry and _free_ the development,” _read_ “FORCE the development.” Mr. Coote also informs us that in the middle paragraph of the first column in the same page, a sentence there in which he gave his reason for discontinuing the use of the salt bath for washing the plates will read better and more correctly as follows:—“Firstly: I found the extra salt bath and long washing required after it to considerably lengthen an already sufficiently tedious method of preparation.”
SUBSCRIBER.—Excuse plain speaking, but your pictures are by no means good—in fact, they are _very_ bad. We are at a loss as to what to attribute their special qualities—whether to want of care or want of knowledge and experience. Carelessness, to all appearance, has had much to do with the matter; for the plate has been badly coated and is torn, and the developer has not flowed smoothly over the surface. After you have acquired some more experience and dexterity in manipulation write again, enclosing a specimen. You need not entertain any fear of your name and address being divulged.
W. K.—No more easy and expeditious method of collecting oxygen in a bag can be adopted than that which has so often been described in our Almanacs and Journals, viz., connecting the bag with the washing bottle by means of an india-rubber tube, the bottle being in turn connected with the retort in which the oxygen is generated. The method of making oxygen from chlorate of potash and black oxide of manganese is the simplest, cheapest, and best to adopt when only a small quantity is required. By a small quantity we here mean such a quantity as will be required by a professional enlarger of photographs in full practice.