_Mr. Weld Taylor's Process._--In your 167th Number (Vol. vii., p. 48.) is a communication from WELD TAYLOR on photographic manipulation, which, in its present form, is perfectly unintelligible. At p. 48. he says: "Twenty grains of nitrate of silver in half an ounce of water is to have half an ounce of solution of iodide of potassium of fifty grains to the ounce added." Now this is unnecessarily mystifying. Why not say: "Take equal quantities of a forty-grain solution of nitrate of silver, and of a fifty-grain solution of iodide of potassium;" though, in fact, an _equal_ strength would do as well, and be quite as, if not more, economical. In the next place, he directs that cyanide of potassium should be added _drop by drop_, &c. It {93} is to be presumed that he means a _solution_ of this salt, which is a solid substance as usually sold. What follows is so exceedingly droll, that I can do nothing more than _guess_ at the meaning. How one _solution_ is to be floated on another, and then, _after_ a bath of nitrate of silver, is to be _ready for the camera_, surpasses my comprehension. Also, further on, he alludes to _iodizing_ with the _ammonio-nitrate_ (I presume of silver). What does he mean? GEO. SHADBOLT. _Dr. Diamond's Services to Photography._--SIR, We, the undersigned amateurs of Photography in the city of Norwich, shall be obliged if you will (privately, or otherwise, at your own discretion) convey to DR. DIAMOND our grateful thanks for the frankness and liberality with which he has published the valuable results of his experiments in the pages of "N. & Q." We have profited largely by DR. DIAMOND'S instructions, and beg to express our conviction that he is entitled to the gratitude of every lover of the Art. We are, Sir, Your obedient servants, T. LAWSON SISSON, Clk., (Edingthorpe Rectory). THOS. D. EATON. JOHN CROSSE KOOPE. JAMES HOWES. T.G. BAYFIELD. G. BROWNFIELD. HENRY PULLEY. W. BRANSBY FRANCIS. J. BLOWERS (Cossey). BENJ. RUSSELL. [Agreeing, as we do most entirely, with the Photographers of Norwich in their estimate of the skill and perseverance exhibited by DR. DIAMOND in simplifying the collodion and paper processes, and of his liberality in making known the results of his experiments, we have great pleasure in giving publicity to this recognition of the services rendered by DR. DIAMOND to this important Art.] _Simplification of the Wax-paper Process._--At a late meeting of the Chemical Discussion Society, Mr. J. How read the following paper on this subject:--