In the nineteenth century, continuous partial attention was a burning problem:
Until the 1820s (when candle technology started to improve markedly), both wax and tallow candles needed frequent “snuffing.” We commonly misunderstand the term snuffing today — it did not mean to put a candle flame out; instead, it meant to trim the candle’s wick. If one did not snuff frequently, then the wick would grow longer as the wax melted, curving over toward the small wall of solid material holding in the melted wax or tallow. The curving wick would then melt the wall, causing the molten material to flow down the candle and be lost. This phenomenon was called “guttering,” and it ensured that the candle burned less efficiently and for a shorter time. Tallow candles left unattended might use just five percent of their material and gutter out within half an hour. …the point is that reading was regularly interrupted — perhaps every ten minutes or so — by the need to snuff a candle.
Candles early in the nineteenth century were probably about as distracting as Twitter is today. Perhaps a distinctive feature of modern life is that the admonition “stay awake, stay alert” has become unusual.
 Eliot, Simon (2001), “‘Never Mind the Value, What about the Price?”; Or, How Much Did Marmion Cost St. John Rivers?” Nineteenth-Century Literature, Vol. 56, No. 2, pp. 173, 177.