In the spring of 1860, Henry David Thoreau was living in his family’s house on Main Street in Concord, working as a surveyor, and giving fiery abolitionist lectures as the country slid closer to civil war. He was also embarking on an ambitious, little-known project of charting his seasonal experiences, noting everything from his “bathing day” in May to the freezing of Walden Pond in December.
This personal project was “more tool than text,” according to Kristen Case, Thoreau scholar and editor of the newly released Henry David Thoreau’s Kalendar, Charts and Observations of Natural Phenomena (2025). It enabled him to gather observations of a landscape in which he found solace during years that were, politically and personally, quite difficult for him.
As Thoreau began his charting project, he watched the United States roil in conflict and, beginning in April of 1861, in outright civil war. He was also dealing with symptoms of tuberculosis that would slowly restrict, then take his life in May of 1862. This book makes Thoreau’s charts, rooted in the Concord-Lexington region, available to the reading public for the first time, and the result is an intimate portrait of a writer, grappling with existential questions in the last years of his life, looking to the natural world for sustenance.
In these handwritten notes, meticulously transcribed by Case and accompanied by her thoughtful essays, Thoreau asserts an almost familial connection to local geography, based on decades of living with attention to otherwise mostly unnoticed events. In his chart of April phenomena, for example, he notes days on which a “high wind rock[s the] house” and when softened ground allows for “plowing generally.” He also observes the day on which he first “leave[s] off [his] greatcoat”—and then, true to New England variability, the day on which he must resume wearing his greatcoat again.
Case’s essays, interwoven among Thoreau’s documents, provide context. When Thoreau began his Kalendar project, he was grieving the execution of abolitionist John Brown, who was found guilty of treason after raiding the federal arsenal at Harpers Ferry in Virginia, hoping to spark a rebellion of enslaved persons. Case notes that Thoreau, in his essay “A Plea for Captain Brown” (1859), insinuated that Massachusetts citizens were as culpable for slavery as peers in slave-holding states. As he mourned Brown’s death, Thoreau’s conscience troubled him too.
Indeed, his charts from that time show him unusually focused on cloud formations, and on basic tasks such as planting his melons and “sit[ting] with open window commonly.” In these notes, there is a subtle portrait of a man grieving, wondering if his civic resistance has been enough. These charts, Case surmises, also represent Thoreau’s rebellion against clock-time, reinforced by industrialization. He was trying to measure time kaleidoscopically, layering events from the same month in adjacent years.
Case links his approach to a famous passage in Thoreau’s Journal: “A year is made up of a… number of sensations and thoughts—which have their language in nature. Now I am ice—now I am sorrel. Each experience reduces itself to a mood of the mind.” Thoreau’s belief that years have patterns, sensory and cognitive, is evident in his Kalendar, where he details his experiences alongside changes of landscape, marking when it is “too cold to paddle” or when winter gloom makes a walker “eat his heart” and “seek sheltered places.” Thoreau’s acute moods, his bouts of melancholia and joy, intermingle with the Concord weather.
In June, for instance, he marks the day on which he begins “to sleep with [an] open window,” as well as a surge of “fresh mackerel” in the Concord River. Thoreau’s “horizontal” view, Case asserts, which de-centers human experience, was also affirmed by his reading of Charles Darwin’s On the Origin of Species (1859), which places humanity within the evolutionary chain. In other words, Thoreau saw himself as part of nature rather than apart from it, which comforted him as he faced his own mortality.
By December of 1861, bedridden Thoreau—who had previously watched two siblings die of tuberculosis—depended on what he could see from his window, cull from prior years’ journals, and glean from the observations of his friend Ellery Channing, who brought him news of the outdoors. Thoreau inhabited time by drawing past experiences into the texture of the present.
One of Thoreau’s winter pleasures, for instance, had been ice skating: he marveled at the speed at which he could travel the frozen Concord River. In January of 1862, his friend Theo Brown skated the river from Framingham to visit Thoreau, confined to his mother’s parlor. Brown reports that Thoreau remarked, “You have been skating on this river. Perhaps I am going to skate on some other.” This was a quiet admission of his looming death and, at the same time, an expression of boyish wonder at the nature of mortality itself. Thoreau had found in his local landscape a means of enriching his life and his departure from it. His Kalendar’s treasuring of everyday textures was a parting gift, one he now shares with us all.