_The Calotype Process._--I have made any first essay in the calotype process, following DR. DIAMOND'S directions given in "N. & Q.," and using Turner's paper, as recommended by him. My success has been quite as great as I could expect as a novice, and satisfies me that any defects are due to my own want of skill, and not to any fault in the directions given. I wish, however, to ask a question as to iodizing the paper. DR. DIAMOND says, lay the paper on the solution; then _immediately_ remove it, and lay on the dry side on blotting-paper, &c. Now I find, if I remove immediately, the whole sheet of paper curls up into a roll, and is quite unmanageable. I want to know, therefore, whether there is any objection to allowing the paper to remain on the iodizing solution until it lies flat on it, so that on removal it will not curl, and may be easily and conveniently laid on the dry side to pass the glass rod over it. As soon as the paper is floated on the solution (I speak of Turner's) it has a great tendency to curl, and takes some time before the expansion of both surfaces becoming equal allows it to lie quite flat on the liquid. May this operation be performed by the glass rod, without floating at all? Photographers, like myself, at a distance from practical instruction, are so much obliged for plain and simple directions such as those given by DR. DIAMOND, which are the result of experience, that I am sure he will not mind being troubled with a few inquiries relative to them. C. E. F. _Hockin's Short Sketch._--Mr. Hockin is so well known as a thoroughly practical chemist, that it may suffice to call attention to the fact of his having published a little brochure entitled _How to obtain Positive and Negative Pictures on Collodionized Glass, and copy the latter upon Paper. A Short Sketch adapted for the Tyro in Photography._ As the question of the _alkalinity_ of the nitrate bath is one which has lately been discussed, we will give, as a specimen of Mr. Hockin's book, a quotation, showing his opinion upon that question: "_The sensitizing agent_, nitrate of silver in crystals, not the ordinary fused in sticks, is nearly always confessedly adulterated; it is thus employed: "_The silver or nitrate bath._--Nitrate of silver five drachms, distilled water ten ounces; dissolve and add iodized collodion two drachms.