Leitz multibeam inteference attachment incident light. Available to purchase for immediate download. Below is an extract from the manual converted to text for a quick impression on the content. Leitz multibeam inteference attachment incident lightMultibeam Interference Attachment for Incident Light InstructionsIntroduction I Outfit 2 Sodium lamp 3 Multibeam head with plane reference mirror 4 Basic interferometer unit 5 Setting the multibeam interferences 6 Sign determinations (elevations or depressions) 7 The measurement 8 Correction factors 9 General suggestions