A transmission apparatus for the x‐ray diffraction of liquids is described. Its main advantages are: (1) precise determination of the intensity in the range of scattering angle 0°<2&thgr;<30°, (2) easy adaptability of commercially available equipment for its construction, and (3) simple temperature control from room temperature up to 250°C. Results obtained with the apparatus are presented, and in a short appendix possible sources of error in the use of a conventional pulse height analyzer for monochromatization are briefly discussed, illustrating the necessity of crystal monochromatization.