I'm doing some research for a story set in Britain during the industrial revolution (roughly 1830s, but no set year yet), and I have found some references to factory working at night - most specifically, the 1833 Factories Act which outlaws children working in mills or factories at night. This evidently suggests that children had previously been working at night, and that adults were still working at night in these industries.
However, I'm struggling to find any detailed accounts of how this practically occurred and how common the practice was. I had previously presumed that factories in this period were closed at night as a consequence of lighting being difficult/expensive to achieve (this source suggests some lighting was possible in the early 1800s, but gives no indication of how commonplace this was).
As such, I'm wondering if anyone can inform me how common night work in factories was during the 1820s and 30s in Britain, and how the average factory would have been lit during this time, if at all. What kind of expense would lighting a factory have been for the owners, and were any measures commonly taken to reduce that expense (for example, candles being produced on-site or lights powered by resources mined on-site)?
Finally, was night working simply a means of squeezing as much production out of the factory as possible, or were there any perceived advantages to operating factories at night? I understand that the temperature in certain factories could be significantly high due to the machinery (discussed as a health concern in the 1819 Cotton Factories Regulation Bill), so might the temperature have been less excessive at night, when the outside temperature would naturally be lower?
What a great question. To answer in short: Yes, night work was expected in many workplaces to ensure 24-hour operation.
The main reason was, to be sure, productivity. In some early mills/factories, the water supply was one factor that made night work more needed, as some tasks could not be done simultaneously. Increasing costs for machinery, rent, licensing etc. made it all the more needed to produce more and more, which meant taking advantage of the artificial lighting industry that took off in the late 1780s.
Sources like General View of the Agriculture of Renfrewshire, published in 1812 in England, reported that mills were lighted generally by candles "but, of late, oil has been used, in several instances in lamps[...] with reflectors attached to them" for it was cheaper (p. 252). A century earlier we already knew that some workers suffer permanent eye damage from needing to work in poor light and often without ventilation.
Additionally, we know that it was a rather common phenomenon thanks to the 1834 Factories Commission, which sent a questionnaire to which 593 manufacturers responded. 480 of them replied to the question "how are the workers lighted at night", and only 8 responded "none". 313 said by gas, 119 by candles, and 103 by oil (the total here is larger than 480 because some had multiple types of lighting).
Most importantly, though, Ian West showed in his 2009 dissertation, "Light satanic mills: the impact of artificial lighting in early factories," that improvement in artificial lighting "did not facilitate increased working hours" (my emphasis, p. 188). For various reasons, night shifts were abandoned over the first 30 years of the 19th century at least in textile mills, for a variety of reasons related and unrelated to the laws of the 1830s. Since much of his data for this comes from statements of factory owners, one needs to be reasonably but not overly suspicious of the magnitude West describes.