The basset clarinet has more low notes than the conventional clarinet, and the English composer Thomas Adès puts it at the heart of Alchymia, a 20-minute chamber piece completed in 2021. Referencing concepts from the worlds of alchemy and Elizabethan London, Alchymia’s opening movement weaves tendrils of delicate string commentary around the clarinet’s descending four-note motif, evoking a transient melancholy. Fantastical swoops and scurryings in the second movement, “The Woods So Wild,” suggest a Shakespearian midsummer night, while the following “Lachrymae” offers a dolorous meditation on a lute piece by John Dowland. Alchymia concludes with “Divisions on a Lute-song,” a heady fusion of popular street-song and 12-tone modernism. Clarinetist Mark Simpson and the Diotima Quartet gave the first performances of Alchymia, and bring a gripping sense of authenticity to this premiere recording.