| Hyposulphite of soda | 8 | ounces. |
| Sel d'or | 7 | grains. |
| Iodide of silver | 10 | grains. |
| Water | 8 | ounces. |
It may be as well to add, that although the nitrate of silver solution used for exciting becomes discoloured, it acts equally well, even when of a dark brown colour; but it may always be deprived of its colour, and rendered sufficiently pure again, by filtering it through a little animal charcoal.
Hugh W. Diamond.
Footnote 6:[(return)]
The addition of one drachm of acetic acid much facilitates the easy application of the albumen to the paper; but it is apt to produce the unpleasant redness so often noticeable in photographs. The addition of forty grains of chloride of barium to the two muriates, yields a bistre tint, which is admired by some photographers.
Footnote 7:[(return)]
Nothing answers so well for this purpose as a small box-wood salad spoon.
Replies to Minor Queries.
Anderson's Royal Genealogies (Vol. viii, p. 198.).—In reply to your correspondent G., I may be permitted to remark that it is generally understood that no "memoir or biographical account" is extant of Dr. James Anderson; but short notices of him and his works will be found on reference to the Gentleman's Magazine, vol. liii. p. 41.; Chalmers' General Biographical Dictionary, 1812; Chambers' Lives of Illustrious Scotsmen, 1833; Biographical Dictionary of the Society of Useful Knowledge, 1843; and also in Rose's New Biographical Dictionary, 1848.