While Jacob Polley's first collection, ''The Brink'', announced a poet of great promise, few readers will be prepared for a work of the mature and slow power of ''Little Gods.'' Polley has been guided more and more by old-fashioned lyric inspiration of the sort all too rare in contemporary English poetry. In the quiet, insistent chants of his love poems and in his almost occult conjurings of time and place, Polley achieves both a directness of expression and unsentimental intimacy of address that only a poet of very considerable gifts could even attempt. ''Little Gods'' unequivocally announces Polley as one of the leading British poets of his generation. Praise for ''The Brink'': ''The kind of poetry that imbues the everyday, the tarnished and burnished, with the possibilities of the transcendent.'' - ''Guardian.'' ''A sparkling collection of crystalline poems, succinct in their observation, precise in their form.'' - ''The Times.''