Fecha de publicación: 06/11/1913 Fuente: WIPO "pollen" 11,535. Lock, W. H., and Pollen, A. H. May 19. Order apparatus.- In an optical range-finding system in which the position of two observing telescopes 4, 5 is repeatedly signalled to a central station, the signalling-circuit 'of each telescope includes contacts 16, 16 controlled manually by the two observers respectively, so that simultaneous observations are signalled to the indicators 12, but an observation by only one observer is not transmitted. Each telescope carries a contact which moves over a number of contacts connected by a cable 13 to the indicator 12. An observer, after each alinement of his telescope, depresses the switch 16 or 16 in the common return circuit 14 or 14, which also includes the contact 16 or 16 controlled by the other observer. The principle underlying the invention, namely the joint control of indicators by independent individuals, is claimed generally.4>5>5>4>5>4>5>4>