Quasistatic and dynamic measurements of the magnetic field induced magnetoelec. polarization (MEH effect) have been performed in the weakly ferromagnetic/ferroelec./ferroelastic phase of point group m'm2' of Ni-Cl boracite between 1.8 and 9 K (=Tc) and above. For the first time the quadratic MEH effect of Ni-Cl boracite has been measured and sepd. from the linear one. The results allow us to discard the existence of a previously assumed antiferromagnetic phase mm2 between 9 and 25 K. Above 9 K, the phase is paramagnetic (mm21;). The coeffs. of the linear (a23, a32) and quadratic (b311, b322, b333, and b223) MEH effect are given for 4.2 K. a32 And b322 are also given vs temp.