Bundle of 12 Thoreau Pencils of the same Hardness -------------------------------------------------------------- John Thoreau entered the pencil business in 1823, after his brother-in-law discovered a vein of plumbago, or graphite, in New Hampshire. Thoreau & Co. quickly gained recognition for their high-quality pencils. By 1829, their pencil manufacturing moved to Concord, MA John’s son, Henry David Thoreau, became involved in the business and started to dig into the manufacturing problems that had made American pencils notoriously inferior to European imports. After researching it at the Harvard Library in 1840, he hit upon the idea of using clay—rediscovering what the French had figured out 45 years earlier—to make the perfect graphite mix. Henry’s formula for kiln-fired pencil leads—a mix of finely ground graphite and clay—could be reliably graded from hard to soft. John Thoreau & Co. was the first American pencil manufacturer to market pencils using a standard of hardness, graded 1-4. The improved Thoreau product appealed especially to engineers, surveyors, carpenters, and artists who valued its consistency. In 1844, Henry made another breakthrough, inventing a grinding machine that produced exceptionally fine graphite powder—the key to a strong, even point. Thoreau pencils won more awards in 1847 and 1849. No one in the United States made better pencils than the Thoreau’s, and the reason for their success was Henry. Around 1849 John Thoreau changed the name of the family business from J. Thoreau & Co. to J. Thoreau & Son. John Thoreau entered the pencil business in 1823, after his brother-in-law discovered a vein of plumbago, or graphite, in New Hampshire. Thoreau & Co. quickly gained recognition for their high-quality pencils. By 1829, their pencil manufacturing moved to Concord, MA John’s son, Henry David Thoreau, became involved in the business and started to dig into the manufacturing problems that had made American pencils notoriously inferior to European imports. After researching it at the Harvard Library in 1840, he hit upon the idea of using clay—rediscovering what the French had figured out 45 years earlier—to make the perfect graphite mix. Henry’s formula for kiln-fired pencil leads—a mix of finely ground graphite and clay—could be reliably graded from hard to soft. John Thoreau & Co. was the first American pencil manufacturer to market pencils using a standard of hardness, graded 1-4. The improved Thoreau product appealed especially to engineers, surveyors, carpenters, and artists who valued its consistency.