Page:Proceedings of the Royal Society of London Vol 4.djvu/342

Rh colour, which shows that the plate is ready to be placed into the camera obscura. I have substituted to the chloride of iodine, chloride of bromine, and have found nearly the same result ; but I prefer chloride of iodine as producing a better effect ; and besides, on account of the noxious smell of bromine.

" The result of my preparation is such, that I have operated in ten seconds with the same apparatus, which, without any chlorine, re- quired four or five minutes ; when using only the original prepara- tion of Daguerre, I have obtained an image of clouds in four seconds,"