With a modern microdensitometer and POSS glass copies, we have performed an automated star counting in two colors, blue and red, over the region containing Bok globule B361. Distribution of the measured extinction values over the projected angular distance from the cloud center was approximated by a power-law, and the resulting power-law indices for the blue and red are shown to be distinctly different from each other. The difference in the power-law index indicates that the mean dust size increases towards the cloud center. Possible physical causes for such size variation are briefly discussed.

ABSTRACT
Ⅰ. INTRODUCTION
Ⅱ. EXTINCTION DISTRIBUTION
Ⅲ. VARIATION OF THE MEAN DUST SIZE
Ⅳ. CONCLUSIONS
ACKNOWLEDGEMENTS
REFERENCES

• S. S. HONG(Department of Astronomy, Seoul National University)
• B. C. KOO(Department of Astronomy, University of California)
• H. S. YUN(Department of Astronomy, University of California)