An attempt was made to detect temperature oscillation in a vertical liquid bridge of molten silicon with a rapid-response optical pyrometer without trying to measure the absolute value of the temperature itself. The liquid bridge was held between a Si rod and a BN rod that was surrounded and heated by a graphite heater, both rods were 12.7 mm in diameter. Thermocapillary convection predominated in the liquid bridge. Temperature oscillation was detected in a liquid bridge 10 mm high and 30 degrees C warmer at the bottom than at the top, corresponding to a Marangoni number of 7.2 x 10(3). The oscillation was slow and wavy at about 0.06 Hz and was superimposed by spikes of about 1.5 Hz. Frequencies observed previously in floating-zone crystal growth of some low Pr materials were mentioned.