British mathematician, astronomer, and inventor (1792-1871) known for his discoveries related to the moons of Saturn and Uranus and for his pioneering work in early photographic processes, including coining the word 'photography' itself. ALS signed “J. F. W. Herschel,” one page both sides, 7.25 x 9, January 30, 1840. Handwritten letter to the distinguished botanist John Lindley, sending thanks for his "Theory of Horticulture," and asking if he could recommend "some work of a merely practical nature which shall go into the actual culture and management of plants—especially bulbs—as I bring to the subject a plentiful stack of ignorance." In fine condition.