Abstract: A slide distributor is disclosed for transferring analysis slides between a plurality of modular elements in a chemical analyzer. The distributor comprises a rotor having a plurality of radial arms each of which has a slide holder adapted to receive an analysis slide and to transport the slide to a selected location in the analyzer. The slide holders are adapted to interact with locating means at each of the elements to facilitate the processing of the slides and transfer of the slides between the elements.

Abstract: Web tracking apparatus for a flexible, closed loop web moving in a closed loop path defined by two or more cylindrical, hard surface supports mounted on a frame and having substantially parallel longitudinal axes which are substantially perpendicular to a plane passing through the respective midpoints of the supports. Included are at least two laterally constraining web supports, at least one of which is a passive positional lateral constraint and includes a cylindrical web-engaging surface which presents substantially no resistance to lateral movement of the moving web, and edge guides mounted adjacent to the cylindrical surface in a predetermined spatial relation to the frame, and having spaced web engaging portions fixed a distance apart which corresponds substantially to width of the web for engaging the edges of the moving web.