  We have observed the production of strings (disclination lines and loops) via
the Kibble mechanism of domain (bubble) formation in the isotropic to nematic
phase transition of a sample of uniaxial nematic liquid crystal. The probablity
of string formation per bubble is measured to be $0.33 \pm 0.01$. This is in
good agreement with the theoretical value $1/ \pi$ expected in two dimensions
for the order parameter space $S^2/{\bf Z}_2$ of a simple uniaxial nematic
liquid crystal.
