I haven't read the book. The author of the article I'm translating mentions him and his novel, I need to include the exact translation of the title but I'm not sure what he meant. Is it a home, a fireplace, an oven or something else? I figured since it is a book about a journey and being in a cloister suggests one is far from home, hearth may mean home here.
It's a long read.
The Wikpedia summary of the book states that
The Cloister and the Hearth often describes the events, people and their practices in minute detail. Its main theme is the struggle between man's obligations to family and to Church.
A glance here and there in the text shows that "hearth" means "fireplace", and metaphorically, "home".
In the most literal sense:
A huge wood fire burned on the hearth, and beside it hung the patient’s clothes.
At night when they sat round the peat fire he bade them observe how beautiful the brass candlesticks and other glittering metals were in the glow from the hearth.
They landed at the little house. It was as clean as a penny, the hearth blazing, and supper set.
There are a few vaguely metaphoric uses of the word, such as this, in Chap 46
"...We keep not open house, but yet we are not poor enough to grudge a seat at our hearth in a cold day to a wayfarer with an honest face, and, as I think, a wounded man. So, end all malice, and sit ye down!”
which does make sense literally, but also in the slightly extended sense of "our home".
But the main use, in the book's title, and in many chapter titles, is metaphoric. This is explained at the end of Chap 73 ("The Hearth"):
You, who know what lies in that word, enlarge my little sketch, and see the young mother nursing and washing, and dressing and undressing, and crowing and gambolling with her first-born; then swifter than lightning dart your eye into Italy, and see the cold cloister; and the monks passing like ghosts, eyes down, hands meekly crossed over bosoms dead to earthly feelings.
In the valley of Grindelwald the traveller has on one side the perpendicular Alps, all rock, ice, and everlasting snow, towering above the clouds, and piercing to the sky; on his other hand little every-day slopes, but green as emeralds, and studded with cows and pretty cots, and life; whereas those lofty neighbours stand leafless, lifeless, inhuman, sublime. Elsewhere sweet commonplaces of nature are apt to pass unnoticed; but, fronting the grim Alps, they soothe, and even gently strike, the mind by contrast with their tremendous opposites. Such, in their way, are the two halves of this story, rightly looked at; on the Italian side rugged adventure, strong passion, blasphemy, vice, penitence, pure ice, holy snow, soaring direct at heaven. On the Dutch side, all on a humble scale and womanish, but ever green. And as a pathway parts the ice towers of Grindelwald, aspiring to the sky, from its little sunny braes, so here is but a page between
“the Cloister and the Hearth.”
Here the contrast is between two worlds, the world of action and the domestic world. (Green, cow-studded Holland versus Italy, with its blasphemy, strong passion, vice.) Most chapters are simply numbered, lacking titles; of those with titles most are either "The Hearth", "The Cloister", or "The Cloister and the Hearth", naming the scene of the chapter. The passage quoted above is at the end of Chap 73, "The Hearth"; the next, Chap 74, "The Cloister" starts out
THE new pope favoured the Dominican order. The convent received a message from the Vatican, requiring a capable friar to teach at the University of Basle. Now Clement was the very monk for this: well versed in languages, and in his worldly days had attended the lectures of Guarini the younger. His visit to England was therefore postponed though not resigned; and meantime he was sent to Basle; but not being wanted there for three months, he was to preach on the road.