Surface Tension ofHe4nearTλ

We have measured the surface tension of liquid ${\mathrm{He}}^4$ for ($(T_{\lambda }-100\mathrm{} \mathrm{mK})<T<(T_{\lambda }+100\mathrm{} \mathrm{mK})$ mK) with a resolution of 1 × ${10}^{-5\mathrm{}}$ using a capacitive differential-capillary-rise technique. The results show a change in the slope of $\sigma \mathrm{}\left(T\right)\mathrm{}$ of 0.0226±0.001 erg ${\mathrm{cm}}^{-2\mathrm{}}$ ${\mathrm{K}}^{-1\mathrm{}}$ centered below the bulk $T_{\lambda }$. A discussion of the critical behavior is given.