  We have conducted J, H, and Ks imaging observations for the Coalsack Globule
2 with the SIRIUS infrared camera on the IRSF 1.4 m telescope at SAAO, and
determined the color excess ratio, E(J-H)/E(H-Ks). The ratio is determined in
the same photometric system as our previous study for the rho Oph and Cha
clouds without any color transformation; this enables us to directly compare
the near-infrared extinction laws among these regions. The current ratio
E(J-H)/E(H-Ks) = 1.91 +- 0.01 for the extinction range 0.5 < E(J-H) <1.8 is
significantly larger than the ratios for the rho Oph and Cha clouds
(E(J-H)/E(H-Ks) = 1.60-1.69). This ratio corresponds to a large negative index
alpha = 2.34 +- 0.01 when the wavelength dependence of extinction is
approximated by a power law which might indicate little growth of dust grains,
or larger abundance of dielectric non-absorbing components such as silicates,
or both in this cloud. We also confirm that the color excess ratio for the
Coalsack Globule 2 has a trend of increasing with decreasing optical depth,
which is the same trend as the rho Oph and Cha clouds have.
