** condition: NM/EX- (1-inch bottom seam split) **  Jon Hassell’s 1980 album “Fourth World, Vol. 1: Possible Musics”, produced alongside Brian Eno, is perhaps the most common entry point in the trumpeter’s catalog, arriving during the latter’s ascendance as a pop theorist and alchemist. But Hassell’s 1978 debut “Vernal Equinox” contains many of the same ideas in a more muted and subtle form. It was one of the groundbreaking albums of its era, channeling a wealth of inspirations into an imaginative framework that would come to resonate with many other listeners and musicians, but in a much more fully formed, if dreamlike, style. Inspired by raga music, particularly the work of the vocalist Pandit Pran Nath, Hassell processes his trumpet sound and focuses on notes that change in tiny increments, giving his melodies a slippery quality where you’re never quite sure where they are coming from or where they might go next. The background is filled with quiet twitches of rattles and bells, gurgling talking drum, and snippets of bird songs, creating a bed of sound that is hard to pin down but easy to absorb as a whole. With Hassell accompanied by Lovely Music’s avant-garde brigade (master Brazilian percussionist Nana Vasconcelos and David Rosenboom on synth), the sources of this LP stretch in all directions, from the “Shhh/Peaceful” jazz of Miles Davis to Indian classical music to twinkling New Age, and open up whole new avenues of exploration for future generations in the process.