Both of these publications cannot fail to be helpful to those members who have the privilege of examining them, for one is sure to learn something by "exchanging experiences." The Chapters which issue these magazines have reason to feel very proud of them. A correspondent who signs herself "Sweet Marie" asks: 1. How to prepare the best and cheapest developer. 2. How to make sensitive paper. 3. How to prepare a polishing solution for ferrotype plates. 4. How to make a ruby lamp. 5. What is stronger water of ammonia. 6. What is bromide of ammonia. As there are almost as many formulas for developers as there are amateur photographers, it would be quite impossible to say which one is the cheapest and best. Sir Knight William C. Davids, of Rutherford, New Jersey, sends the following formula, which he recommends very highly. We shall publish in our papers for beginners several formulas for developing solutions, with prices of chemicals. _Hydroquinon Developer._--Sodium sulphite, 460 grains; sodium carbonate, 960 grains; hydroquinon, 96 grains; water, 16 ounces. 1. Mix and filter before using. In No. 786 will be found a simple developer for instantaneous pictures. 2. Directions for preparing sensitive paper will be found in Nos. 786 and 803. 3. Directions for polishing ferrotype plates will be found in Nos. 797 and 805. 4. A ruby light for dark-room work may be made by taking a wooden starch-box, cutting a square hole in the cover, and pasting two thicknesses of red fabric over the opening. A hole must be made in one end of the box--which answers for the top of the lantern--to allow for ventilation. This must be shielded so as to prevent the escape of actinic rays. This may be done by pieces of tin bent so that air can enter, but no white light escape. A candle should be used with this style of lantern. 5. Ammonia in its pure state is a gas which combines readily with water, water taking up of the gas five hundred times its own volume. This is liquid ammonia, or stronger water of ammonia. By diluting it with water it becomes the spirits of hartshorn, or ammonia water. 6. Bromide of ammonia is formed in the simplest manner by the addition of bromine to water of ammonia. It is very useful in photographic work. It gives great sensitiveness to gelatine and collodion emulsions--combined with pyro for a developer it prevents fog--and is employed in the preparation of sensitive papers. [Illustration: THE PUDDING STICK] This Department is conducted in the interest of Girls and Young Women, and the Editor will be pleased to answer any question on the subject so far as possible. Correspondents should address Editor. Lillie M---- came to see me yesterday, and after she had gone, Maria G----, who was putting a new braid on my second-best gown, said: