A new unit of measurement

Read the section on the experiments for a definition of a new unit in the late 18th century: the candle, the unit of luminosity (end of the chapter on Boulton and Watt's industry); also do the interactive (successively clicking on 1 candle, 2 candles...till you reach a black image), and read the linked pages on the corresponding scientific experiments. Then answer the question: how did the requirements of industry (Boulton's factory) compare with Rumford's scientific experiments on photometry leading to the definition of the new unit? 

Note: the definition of the candle (candela) later evolved, so that you may find different measurements in other countries and later periods.