The demand for human labour differed from season to season because some industries worked to their full capacity during a particular period of time. For excample as works and breweries were especially busy through the cold months. So they needed more workers to meet their peak demand. Bookbinders and printers, catering to Christmas demand, too needed extra hands before December. At the harbour or in port cities, winter was the time that ships were repaired and spruced up. In all such industries where production fluctuated with the season, industrialists usually preferred hand labour, employing workers for the season.
In countries which experienced the shortage of labour force, industrialists were keen on using mechanical power so that the need for human labour can be minimised. This was the case in nineteenth-century America during industrialisation.