  Measurements of neutrino-nucleon and antineutrino-nucleon differential cross
sections using the CCFR neutrino detector at Fermilab have been used to extract
preliminary values of $R ={\sigma_L}/{\sigma_T}$ in the kinematic region
$0.01<x<0.6$, and $4<Q^2<300$ GeV$^2$. The new data provide the first
measurements of $R$ in the $x<0.1$ region. The $x$ and $Q^2$ dependence of $R$
is compared with a QCD based fit to previous data. The QCD fit, which provides
an estimate of $R$ in small $x$ region where $R$ has not been previously
measured, is in good agreement with the new CCFR data.
