What is "gong farmer"

Gong \Gong\, n. [AS. gong, gang, a going, passage, drain. See Gang.] A privy or jakes. [Obs.]
--Chaucer.

Gong farmer, Gong man, a cleaner of privies. [Obs.]

n. (context obsolete English) One who dug out and removed human excrement from privy and cesspits.

Gong farmer (also gongfermor, gongfermour, gong-fayer, gong-fower or gong scourer) was a term that entered use in Tudor England to describe someone who dug out and removed human excrement from privies and cesspits; the word "gong" was used for both a privy and its contents. Gong farmers were only allowed to work at night, hence they were sometimes known as nightmen. The waste they collected, known as night soil, had to be taken outside the city or town boundary or to official dumps for disposal.

As more modern sewage disposal systems such as pail closets and water closets became increasingly widespread in 19th-century England, fewer and fewer cesspits needed to be dug out. The job of emptying cesspits today is usually carried out mechanically using suction, by specialised tankers called vacuum trucks. Hundreds of thousands of people are employed in India as manual scavengers, without equipment or protective clothing.