Disclosed is a process for the manufacture of saturated fatty acid esters by subjecting unsaturated fatty acid esters to hydrogenation in the presence of a catalyst suitable for catalysing the saturation of double bonds in the esters, which is characterized in that said catalyst represents a homogenous complex of a Group VIII metal and a sulfonated phosphite as the polar ionic ligand. The base is provided with pin and control members. An extension part 48 extending outward from the lid 47 is formed in the filter flange 46, and the filter flange 46 has a communication passage 53 inside. Meanwhile, the thermally conductive layer is made from a material with high thermal conductivity that is used to substantially equalize the temperature across the label surface, thereby enabling a faster and cheaper detection of transitions of differential emissivity on the indicium surface.