| 356 / | HD | OPTICS: MEASURING AND TESTING |
| 928 | DD | INVESTIGATING OR ANALYZING MATERIALS BY THE USE OF OPTICAL MEANS, I.E., USING INFRA-RED, VISIBLE, OR ULTRA-VIOLET LIGHT (GO1N 21/00) {5} |
| 929 | DD | .~ Arrangements, or apparatus for facilitating the optical investigation (GO1N 21/01) {1} |
| 930 | | .~.~ Cuvette constructions (GO1N 21/03) |