The orientational fluctuations in a homogeneously aligned nematic liquid cr
ystal were successfully observed with a high-speed video camera. From the s
eries of images obtained, first the spatial Fourier transformation of each
image was computed and then the time correlation function at each wave numb
er was calculated. A theory to analyse the results was developed and by usi
ng it the ratios of the elastic constant to the viscosity were obtained.