Letter to Sarah Hodges
p228“When you want a change try St Martin.”
Fuller, Margaret. The Letters of Margaret Fuller. Edited by Robert N. Hudspeth. Vol. III. Ithaca: Cornell University Press, 1986.
Inferred Fuller's recommendation implies familiarity with his mystical writings, though she does not name a specific work.
Fuller recommends Saint-Martin (Louis-Claude de Saint-Martin, 1743–1803, a French mystic philosopher influenced by Jacob Böhme, per Hudspeth's notes) as a spiritual alternative to Fénelon.