In 1819, Gauss measured a degree of latitude between Gottingen and Altona. In geodesy he invented the heliotrope, by which the sunlight reflected from a mirror is used as a "sight" for the theodolite at a great distance. Through Professor William Weber he was introduced to the science of electro-magnetism, and they devised an experimental telegraph, chiefly for sending time signals, between the Observatory and the Physical Cabinet of the University. The mirror receiving instrument employed was the heavy prototype of the delicate reflecting galvanometer of Sir William Thomson. In 1834 messages were transmitted through the line in presence of H.R.H. the Duke of Cambridge; but it was hardly fitted for general use. In 1883 (?) he published an absolute system of magnetic measurements.

On July 16, 1849, the jubilee of Gauss was celebrated at the University; the famous Jacobi, Miller of Cambridge, and others, taking part in it. After this he completed several works already begun, read a great deal of German and foreign literature, and visited the Museum daily between eleven and one o'clock.

In the winters of 1854-5 Gauss complained of his declining health, and on the morning of February 23, 1855, about five minutes past one o'clock, he breathed his last. He was laid on a bed of laurels, and buried by his friends. A granite pillar marks his resting-place at Gottingen.

WILLIAM EDWARD WEBER was born on October 24, 1804, at Wittenberg, where his father, Michael Weber, was professor of theology. William was the second of three brothers, all of whom were distinguished by an aptitude for the study of science. After the dissolution of the University of Wittenberg his father was transferred to Halle in 1815. William had received his first lessons from his father, but was now sent to the Orphan Asylum and Grammar School at Halle. After that he entered the University, and devoted himself to natural philosophy. He distinguished himself so much in his classes, and by original work, that after taking his degree of Doctor and becoming a Privat-Docent he was appointed Professor Extraordinary of natural philosophy at Halle.

In 1831, on the recommendation of Gauss, he was called to Gottingen as professor of physics, although but twenty-seven years of age. His lectures were interesting, instructive, and suggestive. Weber thought that, in order to thoroughly understand physics and apply it to daily life, mere lectures, though illustrated by experiments, were insufficient, and he encouraged his students to experiment themselves, free of charge, in the college laboratory. As a student of twenty years he, with his brother, Ernest Henry Weber, Professor of Anatomy at Leipsic, had written a book on the 'Wave Theory and Fluidity,' which brought its authors a considerable reputation. Acoustics was a favourite science of his, and he published numerous papers upon it in Poggendorff's ANNALEN, Schweigger's JAHRBUCHER FUR CHEMIE UND PHYSIC, and the musical journal CAECILIA. The 'mechanism of walking in mankind' was another study, undertaken in conjunction with his younger brother, Edward Weber. These important investigations were published between the years 1825 and 1838.

Displaced by the Hanoverian Government for his liberal opinions in politics Weber travelled for a time, visiting England, among other countries, and became professor of physics in Leipsic from 1843 to 1849, when he was reinstalled at Gottingen. One of his most important works was the ATLAS DES ERDMAGNETISMUS, a series of magnetic maps, and it was chiefly through his efforts that magnetic observatories were instituted. He studied magnetism with Gauss, and in 1864 published his 'Electrodynamic Proportional Measures' containing a system of absolute measurements for electric currents, which forms the basis of those in use. Weber died at Gottingen on June 23, 1891.

III. SIR WILLIAM FOTHERGILL COOKE.

WILLIAM Fothergill Cooke was born near Ealing on May 4, 1806, and was a son of Dr. William Cooke, a doctor of medicine, and professor of anatomy at the University of Durham. The boy was educated at a school in Durham, and at the University of Edinburgh. In 1826 he joined the East India Army, and held several staff appointments. While in the Madras Native Infantry, he returned home on furlough, owing to ill-health, and afterwards relinquished this connection. In 1833-4 he studied anatomy and physiology in Paris, acquiring great skill at modelling dissections in coloured wax.