Page:The American Cyclopædia (1879) Volume VII.djvu/693

 ,GEODESY GEOFFROY SAINT-HILAIRE 681 rough and unsightly, of light brown color, and of all sizes up to 12 or 15 inches in diameter ; when broken they present beautiful groups of quartz crystals. Water is sometimes found in the geodes holding the silex in solution, and making with it a milky-looking mixture. As the water evaporates the silex has been known to suddenly form into delicate crystals. Such geodes were at one time abundantly found on Brier creek in Scriven or Burke co., Ga., in a rock composed of hornstone and jasper ; the milky fluid contained in them was used by the inhabitants as a paint or whitewash. (" Ameri- can Journal of Science," vol. viii., p. 286.) GEODESY (Gr. yij, earth, and daietv, to divide), the science and art of laying out divisions of the earth's surface upon a large scale. It differs from ordinary surveying in its measurements, being constantly referred to the spherical sur- face upon which they are made, and reduced to the same horizontal level. Corrections also are made for horizontal parallax in computing the value of instrumental observations, and the calculus of probabilities is applied to resolve their differences. Its object may even be the determination of the spherical curvature of portions of the surface, which is accomplished by the aid of extended series of astronomical observations made in connection with the most exact measurements. The methods of conduct- ing these operations, and contending with the numerous causes of error incident to the im- perfection of the instruments and powers em- ployed, are treated in the article COAST SUR- VEY. The most important results in regard to the figure and dimensions of the earth, de- duced from a comparison of the most extensive and accurate geodetical surveys, are given in the articles EAETH and DEGBEE. GEOFFREY OF MONMOUTH, an old English chronicler, born about 1100, died about 1154. He is supposed to have received his education in the Benedictine monastery near Monmouth, where he compiled his Chronicon sive Historia Britonum, to which he probably owed his promotion in 1152 to the see of St. Asaph. Geoffrey's chronicle professes to be a transla- tion from an old Welsh manuscript which one Walter Calenius, an archdeacon of Oxford, dis- covered in Brittany, and which he requested him to render into Latin. That some part of the work is a translation there seems to be no doubt, as its main features agree with the his- tory of Nennius, written several centuries pre- vious ; but so numerous are the legends and fables interwoven into it, and so extensive is the period it embraces (from Brut, the great- grandson of ./Eneas, to the death of Cadwalla- der or Cead walla, king of Wessex, in 688), that its historical value is very inconsiderable. If historians are inclined to doubt the veracity of Geoffrey, the readers of romance are indebted to him for having preserved and perhaps re- constructed the legends of Arthur and his knights. The work was originally divided into eight books, to which Geoffrey added the book of Merlin's " Prophecies," and was first printed at Paris in 1508. The best recent editions are those of J. A. Giles (1842) and Bohn (1848), both of which are reprints from a translation by Aaron Thompson published in 1718. GEOFFRIN, Marie Therese, a French lady, born in Paris, June 2, 1699, died there in Octo- ber, 1777. Her father, M. Rodet, was in the service of the dauphiness. She was barely 15 when she married M. Geoffrin, a manufac- turer, who was ridiculed on account of his mental inferiority to his wife, but whose for- tune enabled her to dispense hospitalities to distinguished persons. She became a widow in a few years, and remained to the end of her life one of the most conspicuous leaders of European society. She counted among her friends Diderot, D'Alembert, Horace Walpole, Hume, and Gibbon. Count Stanislas Poni- atowski was a constant visitor at her house, and she rescued him from prison by paying his debts. When elected king of Poland in 1764, he said to her, Maman, votre fils est roi. On her visiting him at Warsaw in 1766, the lead- ing members of the Polish nobility came to meet her on the road, and the king had a resi- dence prepared for her. Passing through Vi- enna, she was received with great distinction by the empress Maria Theresa and her son Jo- seph II. She was unceasing in her assistance to literary men, especially to those connected with the Encyclopedic, toward the publication of which she is said to have contributed more than 100,000 francs. Though intimately asso- ciated with philosophers and free thinkers, she was somewhat of a devotee, and her daughter, who became the wife of the marquis de la Ferte"- Imbault, attempted to wean her altogether from intercourse with her former friends. But it was only during the last year of her life that she was prevailed upon to deny her soci- ety to the^encyclopaedists. Morellet published in 1812 Eloges de Madame Geoffrin, compri- sing his eulogy of her and those by D'Alembert and Thomas, and several of her letters. GEOFFROY SAINT - HILAIRE. I. Etienne, a French zoologist, born in Etampes, April 15, 1772, died in Paris, June 19, 1844. He was educated for an ecclesiastical life, but evinced a taste for natural philosophy, and had gained some proficiency as a mineralogist when the revolution broke out. Hauy having been in- carcerated as a recusant priest, his pupil man- aged to procure his liberation, and at the peril of his life he rescued 12 other priests from prison, on the very eve of the massacre of September, 1792. A few months later he was appointed to a subordinate office in the jardin des plantes, and in 1793, on the reorganization of this establishment under the name of muse- um of natural history, he was made 'professor of zoology. Through his exertions, the old specimens were put in order, new ones were procured, and the zoological collections became the richest in the world. In 1795 he welcomed to Paris George Cuvier, then entirely unknown