  The method developed by Stock and Stock (1999) for stars of spectral types A
to K to derive absolute magnitudes and intrinsic colors from the equivalent
widths of absorption lines in stellar spectra is extended to B-type stars.
Spectra of this type of stars for which the Hipparcos Catalogue gives
parallaxes with an error of less than 20% were observed with the CIDA 1-meter
reflector equipped with a Richardson spectrograph with a Thompson 576x384 CCD
detector. The dispersion is 1.753 A/pixel using a 600 lines/mm grating in the
first order. In order to cover the spectral range 3850 A to 5750 A the grating
had to be used in two different positions, with an overlap in the region from
4800 A to 4900 A. A total of 116 stars was oberved, but not all with both
grating positions. A total of 12 measureable absorption lines was identified in
the spectra and their equivalent widths were measured. These were related to
the absolute magnitudes derived from the Hipparcos Catalogue and to the
intrinsic colors (deduced from the MK spectral types) using linear and second
order polynomials and two or three lines as independent variables. The best
solutions were obtained with polynomials of three lines, reproducing the
absolute magnitudes with an average residual of about 0.40 magnitudes and the
intrinsic colors with an average residual of 0.016 magnitudes.
