Sunday, October 14, 2012

Sir Edward Sabine

Edward Sabine was born on October 14, 1788 in Dublin, Ireland. He was the fifth son and ninth child of Joseph Sabine and Sarah Sabine nee Hunt. Sabine's mother died one month after his birth. He obtained a military education first at Marlowe and then at Royal Military Academy at Woolrich. He was commissioned as an artillery officer in 1803, becoming a captain ten years later, and he rose to the rank of general in 1870. Sabine was stationed at Gibraltar during the Peninsular War and saw his first action during the War of 1812. On his voyage to Canada the ship he was on was captured by an American privateer. The ship was eventually recaptured by a British frigate and he made his way to Quebec. Sabine served in the Niagara campaign and took part in the siege and assault on Fort Eire, serving with distinction.

He returned to England in 1816 and began doing research in astronomy, terrestrial magnetism, and ornithology. He became a member of the Royal Society in 1818. Also in 1818 Sabine served as astronomer during the Ross expedition looking for the Northwest Passage. During the expedition Sabine took magnetic readings of the Earth and studied birds, identifying a new species (Larus sabini). The following year Sabine took part in another Northwest Passage expedition, this time under William Perry. The expedition was the first to make it north of the arctic circle, returning in 1820. In 1921 Sabine received the Copley Medal for his various researches during this expedition.

For the next couple years Sabine toured the world taking measurements with his pendulum. The period of a pendulum depends on its length and the force of gravity on the bob at the end of the string or arm. Because Earth is not a perfect sphere (it is an oblate sphere which bulges at the equator) the distance to the center of the Earth is not uniform at different latitudes. This causes the gravity at the earth surface to vary at different latitudes with the acceleration of gravity rising as you move toward the poles. The period of Sabine's pendulum, swung at different latitudes, differed due to the differences in gravity caused by the differences in the distance to the center of the Earth. With this experiment Sabine demonstrated that the earth is not perfectly spherical. For this work Sabine was honored with the Lalande Medal of the Institute of France in 1826

When the British Board of Longitude was abolished in 1828, Sabine, with Michael Farady and Thomas Young, was appointed as a scientific adviser to the Admiralty. In this position Sabine advocated for the creation of magnetic measuring stations throughout the British Empire. Because changes in the Earth's magnetic field, which at the time were believed to be the result of weather patterns, affected compass readings these magnetic observatories were built. The observations from these observatories were collated by Sabine in London and he discovered that changes in the Earth's magnetic field were due to sunspot activity and the influence of the moon.

Sabine won a gold medal from the Royal Society in 1849 and served as its president from 1861 to 1871. Sabine was knighted in 1864 and has a crater on the moon named after him. The California grey pine (Pinus sabineana) is also named after him.

He died on June 26, 1883 and was buried in his family vault in Tewin, Hertfordshire.


Anon.; "Sir Edward Sabine"; The Observatory (1883)6:232-233

Vetch, Robert Hamilton; "Sabine, sir Edward"; Dictionary of National Biography, 1885-1900, Volume 50;

Edward Sabine Wikipedia Entry

Sunday, October 7, 2012

Rudolf Leuckart

Karl Georg Friedrich Rudolf Leuckart was born on October 7, 1822 in Helmstedt, Lower Saxony, which would later become part of Germany. His father owned a printing plant and his uncle, Friedrich Sigismund Leuckart, was a professor of zoology. His uncle awakened the interest in zoology in his young nephew, who collected insects. Leuckart was interested in pursuing a career in zoology, but a the time there were no university programs devoted to it, so he was forced to study medicine, which he did at the University of Gottingen starting in 1842. At Gottingen Leuckart met zoologist Rudolf Wagner and became his assistant in 1845. Leuckart's dissertation, the same year, won a university prize. Leuckard became a zoology lecturer and in 1848 he went on his first expedition to the North Sea to study marine microorganisms.

In 1850 Leuckart became professor of zoology at the University of Giessen. The years at Giessen were productive for Leuckart and he did a lot of the work studying parasites. He proved that cattle were the carrier of beef tape worm (Taenia saginata) and that pigs were the carriers of pork tapeworm (Taenia solium). Most vertebrate species have a tapeworm species that has evolved to live in its intestines. His studies of Trichina, the cause of trichinosis was used by Rudolf Virchow's campaign for meat inspection laws in Germany. With Virchow and Friedrich Albert von Zenker, he was the first to document the life cycle of Trichnella spiralis. For his work on parasites Leuckart is known as the father of parasitology. He also studied insects, documenting the anatomy and life cycle of the honey bee and the life cycle of Hippoboscoidea, (called Pupipara at the time) a super-family of obligate blood parasites that includes tsetse flies and bat flies.

In 1861 he was named a privy councilor by the King of Saxony and was awarded an honorary PhD by University of Giessen. In 1869 he moved to the University of Leipzig. At first the facilities were inadequate, but in 1880 a zoological institute was built according to his specifications. It quickly became a center for zoological learning and attracted students from around the world. While at Giessen he created a series of zoological posters showing  species of invertebrates that have been used world wide as teaching aids. Leuckart's magnum opus, a two volume work on human parasites and the diseases they cause remained unfinished at the time of his death but was still widely used by students of parisitology.

 Leuckart died in Leipzig on February 6, 1898.


Kellog, Vernon L.;"Rudolf Leuckart"; Psyche (1898)8:214-215

"Leuckart, Karl Friedrich Rudolph"; in The Complete Dictionary of Scientific Biography; Charles Scribner's Sons; 2008

Rudolph Leuckart Wikipedia Entry