Woolf’s use of parentheses

And Elizabeth didn’t like it either. (Still the last tremors of the great booming voice shook the air around him; the half-hour; still early; only half past eleven still.)

Woolf, Virginia. Mrs. Dalloway. New York: Harcourt, Inc. 1925. Print. p.49

Woolf seems to use parentheses a lot in this writing. It seems that it usually is used to give information on what a specific characters internal thoughts and detail that is going on around them.