_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?