… instruments and apparatus for measuring or checking viscosity, porosity, expansion, surface tension or the like; …
Explanatory notes
… instruments and apparatus for measuring or checking viscosity, porosity, expansion, surface tension or the like; … and spectrographs using optical radiations (UV, visible, IR) 9027.50 ‑ Other instruments and apparatus using … (particularly those used for infra‑red or ultra‑violet rays) are fitted with prisms or with diffraction …