THE Royal Photographic Society's Annual Exhibition is now open at the Society's House, 35 Russell Square, London, admission being free; and it closes on October 9. In the Scientific and Technical Section the items that seem to be the most novel or the least often seen are some results obtained by a combination of the cinematograph and microscope, and a photograph of the ultra-violet spectrum of silicon by Prof. A. Fowler, of the Imperial College. This is done in sections, from wave-length 2820-2420 Å.U. on ordinary plates, from 2250-1840 A.U. on plates smeared with a fluorescent oil, and from 2150-1250 Å.U. on Schumann plates using a vacuum grating spectograph.