Neptune's Needle

Naturalist. de Pourtales was introduced to natural history through botanical walks with his nursery maid. In 1840 Pourtales joined Louis Agassiz's group studying the Swiss glaciers; he was among the founders of the Hotel Neuchotelois, the rock-walled hut that served as a base for summer glacier studies. Pourtales assisted Agassiz with meteorological and internal temperature studies on the glaciers. In 1847 Pourtales followed Agassiz to the United States and took up residence at his mentor's East Boston house. There he helped Agassiz with studies of local glacial deposits and marine invertebrates, including dredging from the U.S. Coast Survey vessel Bibb. In 1848 Pourtales joined the U.S. Coast Survey, then directed by Agassiz's friend A. D. Bache; he engaged in a variety of hydrographical studies and directed the tidal division from 1854 until his retirement.

In 1844 incoming director Bache had ordered the preservation of samples of the sea bottom brought up on sounding leads. These were studied by the microscopist Jacob W. Bailey at West Point, and by Pourtales, who worked on a map of sediment types between Massachusetts and New Jersey for use by navigators. After Bailey's death in 1857, Pourtales was given charge of all the nearly 9,000 bottom samples collected by Coast Survey vessels. He published the results of his studies in 1871 in Petermanns Geographische Mitteilungen. There, in a colored map, Pourtales showed the distribution of sediment types on the U.S. East Coast, presenting data that were not superseded until the 1960s.

In 1854 Pourtales reported work on sediment samples from the Blake Plateau off eastern Florida that revealed foraminiferans (minute single-celled animals) at depths of as much as 1,050 fathoms. Pourtales believed these animals were living at these depths, rather than merely sinking or drifting from the surface or shallow water. Biologists were then generally convinced of the truth of a suggestion by Edward Forbes, a prominent English marine biologist and geologist, that life quickly diminishes and disappears at depths greater than 200 fathoms. It was obvious that the tiny sounding lead samples were inadequate to give a picture of the ocean floor, so the new Coast Survey superintendent Benjamin Peirce, at his friend Agassiz's instigation, ordered deep-water dredging under the supervision of Pourtales. In 1867 from the Coast Survey ship Corwin, and in 1868 and 1869 from the Bibb, Pourtales dredged samples from the Florida Straits (between Florida and Cuba) containing a wide variety of invertebrates clearly inhabiting the bottom down to 850 fathoms. At about the same time (1868-1870), the British biologists Sir Wyville Thomson, William B. Carpenter, and Gwyn Jeffreys on the Lightning and the Porcupine were making similar discoveries in the eastern Atlantic and the Mediterranean. Pourtales's reports on the corals, crinoids, and holothurians from the dredging cruises were published by the Museum of Comparative Zoology at Harvard. Agassiz named the Pourtales Plateau southeast of the Florida Keys for him in 1869. Also in 1869, Alexander Agassiz described a new genus of sea urchins, Pourtalesia, later found to be one of the most widely distributed of deep-water animals.

In 1871 Pierce invited Louis Agassiz on a cruise from Boston to San Francisco on the Hassler, a new Coast Survey ship. Pourtales was in charge of the dredging, which proved largely unsuccessful because of equipment failure. During sojourns on land, Pourtales assisted Agassiz in glacial studies, finding evidence of glaciation in the Strait of Magellan and on the coast of Chile.

Pourtales's father died in 1870, and Pourtales, now a count, was financially able to resign from the Coast Survey and accept the keepership of the Museum of Comparative Zoology. There he dealt with the routine administration of the museum and described the collections from the Hassler cruise and from Alexander Agassiz's 1877-1878 and 1878-1879 cruises on the Coast Survey ship Blake. He lived to complete important studies on deep-sea corals. He taught at Agassiz's Anderson School of Natural History at Penikese Island, Massachusetts, in the summer of 1873.

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Peter Richards