Between 1748 and 1749, Kalm, a Swedish naturalist and student of Linnaeus, traveled throughout northeast America, specifically in Pennsylvania, Delaware, New Jersey, New York, and Canada, surveying the countryside, and recording notes on the inhabitants, the fauna, and the flora of the region. Among his companions on a trip into the back country of New York was American naturalist John Bartram. Returning to his native Stockholm, Kalm published the first edition of his observations between 1753 and 1761. Translated into English by John Reinhold Forster as Travels into North America; containing Its natural history, and a circumstantial account of Its plantations and agriculture in general, with the civil, ecclesiastical and commercial state of the country, the manners of the inhabitants, and several curious and important remarks on various subjects. 3 vols. London, 1770-1771.
Digital facsimile of the original Swedish edition from Biodiversity Heritage Library at this link; of the English translation, also from Biodiversity Heritage Library at this link.