1840s

1840s ke decade 1 January 1840 se suruu bhais rahaa aur 31 December 1849 ke khalaas bhais rahaa. Ii 19th century ke 5th decade rahaa.

Ii decade jaada kar ke Revolutions pf 1848 khaatir jaana jaae hae. Europe bhar me liberals aur kaam kare waala log social reform ke khaatir andolan kare rahin, aur universal suffrage aur parliamentary reform maangin. 1848 me karl Marx communist manifesto ke likhis rahaa. Mexicam-American War ke baad America dher Mexico ke jamiin ke aapan niche kar liis.