John Thomson, identifying himself as a practical hatter, opens his 1868 treatise by asserting that theory and practice, though distinct, must be reconciled for perfection in any trade. He writes with a dual audience in mind: fellow workmen, whom he hopes will forgive any errors and find new ideas, and readers seeking to understand the why behind hat-making. Thomson explicitly avoids technical jargon, yet his prose is dense with process details, from the blowing machine to the fulling mill. The book’s structure follows the chronological manufacture of a felt hat, but Thomson also includes a history of hats, descriptions of furs and wools, and notes on fashions. His tone is earnest and occasionally defensive, aware that trade secrets and workshop prejudices may invite criticism.

Theory, Practice, and the Practical Hatter’s Voice

Thomson begins with an axiom: theory and practice are essentially different, yet they “long for a mutual understanding.” He positions himself as a mediator, a practitioner who can explain the why behind workshop usages. He laments that workmen are “so diffident in writing,” implying that his treatise fills a gap. The opening paragraphs reveal a tension between revealing trade secrets and maintaining credibility among peers. Thomson acknowledges that many workshop “secrets” are merely trifles to gain a name, yet he proceeds to detail precise operations—shaving, stiffening, ruffing—with the authority of long experience. His voice is that of a craftsman who values both manual skill and explanatory clarity.

The Material Logic of Fur, Wool, and Hair

Thomson’s treatise is grounded in the physical properties of materials. He notes that “the quantity and quality of fur, or an entire change of materials, produce quite a different appearance” in the hat’s look, wear, and price. The shape of the cone must be adjusted for high or low crowns, broad or narrow brims. He describes how coarse hairs work to the surface during felting, necessitating shaving—a process where a workman “with a long bladed sharp knife in hand, sweeps rapidly over the surface.” The stiffening process, he explains, is not a paste but a varnish that coats each hair individually, leaving interstices open for ventilation. This attention to material behavior—why certain furs felt better, how water-proofing affects breathability—distinguishes the treatise from a mere recipe book.

Contrasting Finishes: Brush Hat vs. Plated Beaver

Thomson draws a clear distinction between two types of felt hats. The “brush hat” raises a nap directly from the body itself: after shaving, the hatter uses a stiff brush, card, and comb to raise a nap on the half-solidified body, resulting in a rough, flowing surface. In contrast, hats destined for a finer nap receive a “plated cover of beaver” or other fine fur, applied as a veneer. Thomson calls this “a kind of veneering or outside plating.” The decision to plate or not affects the entire manufacturing sequence: plated hats must go back to the plank kettle for additional teasing and ducking. This contrast between a hat’s body and its surface finish—between structural integrity and aesthetic appearance—runs through the technical descriptions.

Thomson’s treatise is best read as a period document of industrial craft, where the author’s pride in his trade is matched by a desire to systematize knowledge. Readers interested in the history of technology will find value in his step-by-step accounts, while those curious about material culture can trace how fur, wool, and hair were transformed into everyday objects. The book rewards attention to its small details—the weight of a “precious morsel” of beaver, the width of rollers—as evidence of a working hatter’s world.