Catalogue Page from Exhibition Catalogue: 1909 Fifty-fourth Annual Exhibition of the Royal Photographic Society of Great Britain

showing (E09A027) Exhibit no. 395 396 397: Frame III: 2 plates of the Yttrium spectrum; Y from Gadolinit and from Orthit. 1 plate showing part of the banded spectrum of metallic Boron, 1 plate showing band-group of Ca F2. by Prof. H. Kayser ()