  We present Balmer lines spectroscopy for a sample of 48 Be stars. For most of
them, H$\alpha$ and H$\beta$ have been observed more than two times, in a total
period spanning almost two years between 2008 and 2009. Spectral synthesis of
the H$\alpha$ profile was performed following two steps: photospheric
contribution was computed by using Kurucz's code ATLAS9 and SYNTHE, and disk
emission was derived by the approach of Hummel & Vrancken (2000, A&A, 302,
751). For 26 out of 48 stars, a modeling of the total H$\alpha$ emission has
been attempted. By this modeling we derived an estimation of the disk radius,
as well as the inclination angle between the rotational axis with line of sight
and the base density at the stellar equator. For the stars observed more than
once, we also discuss the variability of H$\alpha$ and H$\beta$ for what
concerns both the equivalent width and the spectral profile. We found 16 stars
with variable equivalent width and 7 stars with clear signs of profile
variation. We derive effective temperature, gravity, and projected rotational
velocity. We found 13 stars whose equivalent width is variable with a
confidence level greater than 80% and 7 object for which spectral profiles show
change with time. According to the commonly used classification scheme, we
classified 16 stars as belonging to class 1, 13 to class 2, 11 are shell stars,
6 objects do not show net emission, and 2 stars display transitions from class
1 and 2. For the class 1 stars, we confirm the correlation between $v \sin i$
and peak separation. Concerning the geometry of the disk, we derived the base
density at the stellar equator, the radius, and the inclination angle between
rotational axis and line of sight. The maximum concentration of stars occurs
for disk dimensions ranging in the interval of 6 to 8 stellar radii and for
inclination angles going from 23$^\circ$ to $35^\circ$.
