ERENT SPECTRAL TYPES._

+---+-------+-------+-------+-------+
|Sp.|Number | _m_ | _M_ | [mu] |
+---+-------+-------+-------+-------+
| B | 15 | +2.03 | -1.67 | 0".05 |
| A | 46 | +3.40 | +0.64 | 0.21 |
| F | 125 | +5.60 | +2.10 | 0.40 |
| G | 179 | +5.77 | +1.68 | 0.51 |
| K | 184 | +6.17 | +2.31 | 0.53 |
| M | 42 | +6.02 | +2.30 | 0.82 |
+---+-------+-------+-------+-------+

We shall later consider all parallax stars taken together. We find from
table 6 that the apparent magnitude, as well as the absolute magnitude,
is approximately the same for all yellow and red stars and even for the
stars of type F, the apparent magnitude being approximately equal to +6m
and the absolute magnitude equal to +2m. For type B we find the mean
value of M to be -1m.7 and for type A we find M = +0m.6. The proper
motion also varies in the same way, being for F, G, K, M approximately
0".5 and for B and A 0".1. As to the mean values of _M_ and [mu] we
cannot draw distinct conclusions from this material, because the
parallax stars are selected in a certain way which essentially
influences these mean values, as will be more fully discussed below. The
most interesting conclusion to be drawn from the parallax stars is
obtained from their distribution over different values of _M_. In the
memoir referred to, ADAMS has obtained the following table (somewhat
differently arranged from the table of ADAMS),[16] which gives the
number of parallax stars for different values of the absolute magnitude
for different spectral types.

A glance at this table is sufficient to indicate a singular and well
pronounced property in these frequency distributions. We find, indeed,
that in the types G, K and M the frequency curves are evidently
resolvable into two simple curves of distribution. In all these types we
may distinguish between a bright group and a faint group. With a
terminology proposed by HERTZSPRUNG the former group is said to consist
of _giant_ stars, the latter group of _dwarf_ stars. Even in the stars
of type F this division may be suggested. This distinction is still more
pronounced in the graphical representation given in figures (plate IV).

TABLE 7.

_DISTRIBUTION OF THE PARALLAX STARS OF DIFFERENT SPECTRAL TYPES OVER
DIFFERENT ABSOLUTE MAGNITUDES._

+-------------------------------------------------+
| | | | | | | || |
| M | B | A | F | G | K | M || All |
|----