Many publications recommend a definite temperature range for the Babcock centrifuge, but do not state how this temperature should be measured, A thermometer placed in the shell of the centrifuge may show a temperature very different from that in the area wherein the bottles are placed. An ordinary six-inch stem, mercury type, maximum recording 0–220° F thermometer, suitably counter-balanced, can be placed in the centrifuge cup to measure the maximum temperature reached during the test. Examples are given of temperature measurements made by this method, compared with those shown by the thermometer regularly used in the centrifuge.