Abstract: In apparatus for picking up a test sample of molten metal or metal alloys and measuring the cooling curve of said sample, comprising a sample receptor and an optical conductor leading from the receptor to a transducer, the receptor is a small, open ended refractory tube having a cavity for receiving the molten sample arranged at the free extremity of a lance with the optical conductor contained within the lance and terminating at the cavity in said receptor and a barrier is disposed between the cavity and the optical conductor, the barrier consisting of a heat resistant, highly thermally conductive material of such quality as to cause the material of the melt sample which is picked up to adhere thereto.

Abstract: The invention relates to a method for measuring the cooling curve of a test sample of metal or a metal alloy, in particular cast iron or cast steel, for the differential thermal analysis in which the difference of the cooling curve of the test sample of a fixedly given comparative curve which satisfies Newton's law of cooling (U=U.sub.0 .times.e.sup.-t/RC, the U.sub.0 parameter being the maximum value at the point in time t=0 and the RC parameter being the time constant) is formed, said comparative curve being brought to coincidence with a section of the cooling curve of the sample by adjusting its parameters so that the difference can then be formed between the adjusted comparative curve and the cooling curve.