(Denison's.)
No. 1 should be made to register Beaumé's scale, 45 deg., the percentage of perchloride in this solution is 47, and the specific gravity 1.444.
| No. 2, 40 | deg.; | percentage, | 41; | spec. grav. | 1.375 |
| No. 3, 38 | " | " | 38; | " | 1.339 |
| No. 4, 35 | " | " | 35; | " | 1.313 |
| No. 5, 27 | " | " | 27; | " | 1.225 |
From an article in the Photographic News (English), Nov. 1, 1889, as practiced in India.
Biting Bath.
(Waterhouse.)
| No. 1, | sp. grav., | 1.444; | ap. per ct. of | Fe2, Cl6 = | 47 |
| No. 2, | " | 1.375; | " | " | 41 |
| No. 3, | " | 1.339; | " | " | 38 |
| No. 4, | " | 1.313; | " | " | 35 |
| No. 5, | " | 1.225; | " | " | 27 |
A stronger solution of 48 deg. has been tried (by the above) but has no penetrating power through even the thinnest film.
Another Formula.
For large plates, 20 lbs. perchloride of iron and distilled water, until weight amounts to 1.500 grammes per 1000 c.c. From this four (4) solutions are made, at