Abstract: A ribbon-like flat web having a plurality of side by side depressions is fed through a horizontal slot having a downward facing surface having an aperture communicating with a reservoir of reagent containing solution. The web is urged against the downward facing surface to provide sealing as the solution is fed into the upward facing depressions. The aperture communicating with the reservoir is profiled as a parallelogram having a leading edge which is oblique to the direction of movement. After emerging from the dispensing apparatus the exposed solution is dried in hot air, followed by spray application of a second solution, further drying in hot air, and application of a backing to form capillary chambers. The method is especially useful for manufacturing coagulation assays having magnetic particles and thromboplastin.