A thousand goose bumps rebelled against the warm night air. They did a nifty soft-shoe up the spine and exploded in shivers of delight. Hearing Judy Collins sing will do it every time.

Collins' show last night at Wolf Trap proved once and for all the power of an exquisite melody in the hands of an even more exquisite voice. By the time she had finished a Stephen Sondheim medley with a haunting rendition of "Send in the Clowns," every nerve ending in the house was crying out for more.

Backed by a tastefully restrained three-piece group and a sparse lighting scheme, Collins avoided flashy displays and let her vocals do all the talking. Whether singing a lovely ballad or a springy country number, she demonstrated a sensitivity and emotional commitment to her music that infused the lyrics and theme lines with a depth they didn't always have on their own. On one piece she actually sang a caappella along with a tape of "singing" whales -- and brought it off! Anyone who can transcend a pop culture cliche of that magnitude has to be something of a genius.

Collins ended her show with "Amazing Grace" -- a song whose title was as appropraite for this performance as was its timeless melody. An excellent, excellent concert.