Complex sentence: In 1837 he was appointed Officiating (acting) Commissioner of Revenue at Bhagalpur (12th Circuit); also, however, he was appointed to Suheswan, a post he apparently never took up.
Split into simpler sentences: In 1837 he was appointed Officiating (acting) Commissioner of Revenue at Bhagalpur (12th Circuit). Also, that, he was appointed to Suheswan, but this was a post he never took up.