A two-beam interferometer for Fourier Transform spectroscopy has a double pivot scanning mechanism. The interferometer has two rigid pendulums that are each rotatable to swing around an associated one of distinct axes of rotation. A linkage links the two rigid pendulums to each other and
A conduit-mounted light-transmitting device (10) for allowing optical analysis of a substance through a process line conduit (14) made of a light-transmitting material. The device (10) comprises a clip (24) adapted to be detachably secured about the conduit section. The clip (24) def