A Manual Of Photography

H8HBBSBHHHS åW^Wå^ME 152 SCIENTIFIC INVESTIGATIONS ON PHOTOGRAPHY. knowledge, which promise to remove many of the anomalies with which M. Claudet and others have attempted the solution. The extension of the luminous image beyond the limit ofF chemical spectrum, a set of new colours which arc dh great difficulty made to permeate some media ^ apparently big transparency, are among the very important discoveries eminent analyst. Upnpfif, The author may he allowed to mention here, for the benefit of those who are disposed to pursue this class of that lie has just communicated (beptember 18a2) to th Msh Association at Belfast, some experiments on the toad spectra, as obtained after the solar rays have been made to permeate coloured media. Some of the results are ot a very remarkable kind, and promise to elucidate many points in con- nection with the chemical action of the suu s rays, which are at present involved in much obscurity.