Ancient history

Why did the emancipation act provide for full in 1838 and 1840 than 1834?

There wasn't an Emancipation Act passed in 1838 or 1840. The Slavery Abolition Act 1833 was passed on 28 August 1833, and enforced on 1 August 1834, and abolished slavery throughout the British Empire, with the exceptions of the territories managed by the British East India Company and Ceylon, which were covered by a separate Act passed the following year.