Complex sentence: An 1884 article discussed the composition and geographical distribution of immigrant populations, and expressed optimism the newest Americans would assimilate into the larger population, while warning that measures should be taken against potential threats to national unity through fractionalization.
Split into simpler sentences: An 1884 article discussed the composition and geographical distribution of immigrant populations, and expressed optimism towards to the prospect of the newest Americans assimilating into the larger population. At the same time, the article warned that measures should be taken against potential threats to national unity through fractionalization.