. Journal. Fie. 1-5mm. space between the photographic and the glnssplates. the glass plates the extension of the darkening toward thecentre increased more and more. (Fig. 4.) \fter S a photographic plate or 42 hours on aclosed, vessel of thin glass containing a 30 volome^ueoussolution of hydrogen peroxide, no darken,, of; »? platewas observed wl„„ tin- plate was developed 1 he m ; Iwas made perfectly air-tight, so that it was quite impossiblefor any peroxide vapour to escape. Further, a small vessel of glass containing 30 volumehydrogen peroxide solution was loosely covered with a Fig. 5.

---

. Journal. Fie. 1-5mm. space between the photographic and the glnssplates. the glass plates the extension of the darkening toward thecentre increased more and more. (Fig. 4.) \fter S a photographic plate or 42 hours on aclosed, vessel of thin glass containing a 30 volome^ueoussolution of hydrogen peroxide, no darken,, of; »? platewas observed wl„„ tin- plate was developed 1 he m ; Iwas made perfectly air-tight, so that it was quite impossiblefor any peroxide vapour to escape. Further, a small vessel of glass containing 30 volumehydrogen peroxide solution was loosely covered with a Fig. 5. second cylinder of thin glass and a photographic | Jplaced upon it for 42 hours. On developing, the pi,showed no darkening at the part where it had toucylinder; the remaining parts of the plate, BOWWappeared dark. (Fig. 5.) On examining a sheet of gelatin placed uponperoxide solution over a thin sheet of glass by meantitanium reagent and of the chromic aeid, no coloratwas noticeable. (c) Experiments with thin

---

Size: 1667px × 1498px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No

Keywords: ., bookcentury1800, bookdecade1880, booksubjectchemist, bookyear1882