Complex sentence: Demand grew quickly, and in 1869 Lysaght purchased a larger site at St Vincent's, Bristol, for a new factory which by 1878 employed 400 men and produced 1000 tons of galvanised iron sheet a month.
Split into simpler sentences: Demand grew quickly, and in 1869 Lysaght purchased a larger site at St Vincent's, Bristol, for a new factory. By 1878 the factory employed 400 men and produced 1000 tons of galvanised iron sheet a month.