  We carried out magnetotransport experiments under hydrostatic pressure in
order to study the nature of the metal-insulator transition in BaVS$_3$.
Scaling relations for $\rho(T,H,p)$ are established and the pressure dependence
of the spin gap is determined. Our new results, in conjunction with a
re-analysis of earlier specific heat and susceptibility data, demonstrate that
the transition is weakly second order. The nature of the phase diagram in the
$T$--$p$--$H$ space is discussed.
