Abstract: An optical guide comprises at least one optical fibre and, extending lengthwise of the guide and in contact with the optical fibre or fibres, a body of compressible cellular material, for instance in the form of at least one separately formed elongate member. The arrangement is such that when the guide is stressed in such a way as to subject the optical fibre or fibres to a tensile force, the optical fibre or each of said fibres can move transversely of the guide to compress the compressible cellular material with which it is in contact and thereby reduce the strain that would otherwise be imparted to the fibre or fibres. Preferably the optical fibres are assembled about and in contact a longitudinally central core member of which at least an outer peripheral layer is of compressible cellular material.

Abstract: Method and apparatus for dispensing particulate material in portions of predetermined weight by providing a flow of material measurable by a radiation detector, measuring the flow rate per unit time of the material and removing successive determined portions of the material from the flow when the measurement indicates that each such portion is of predetermined desired weight.

Abstract: Apparatus for continuously measuring the bulk density of particulate material such as cut tobacco comprising a measuring column with level detection and density indicating means, a weighing conveyor and control means for driving the conveyor at speeds determined by signals from the level detecting means.