Page:Supplement to the fourth, fifth, and sixth editions of the Encyclopaedia Britannica - with preliminary dissertations on the history of the sciences - illustrated by engravings (IA gri 33125011196181).pdf/258

 of the telescopes thus constructed. Some of them were said to answer extremely well; but, whether from want of activity on the part of the tradesman, or from defect of temper in the patentee, these instruments never acquired much circulation. It was alleged that the liquid by degrees lost its transparency. Indeed we suspect that there is no combination in which liquids are concerned, which can be judged sufficiently permanent for optical purposes. It seems hardly possible to preclude absolutely the impression of the external air; the liquid must, therefore, have a tendency both to evaporate and to crystallize; and, in the course of time, it will probably, by its activity, corrode the surfaces of the glass.

The manufacture of achromatic telescopes in England furnished, for a long period, a very profitable article of exportation. Even after the introduction of those instruments was prohibited by several foreign governments, the object-glasses themselves, in a more compendious form, were smuggled abroad to a large amount. In fact, no flint-glass of a good quality was then made on the Continent. A very material alteration, however, in that respect, has recently taken place, at least in France; where the stimulus impressed by the revolution has worked so many changes, and where ingenuity and science, in most of the mechanical arts, have so visibly supplied the scantiness of capital. The French now construct achromatic telescopes, equal, if not superior, to any that are made in England. Dolland formerly had an agent settled at Paris for vending his glasses; but, during the gleam of peace which followed the success of the allied sovereigns, it was found that this establishment could no longer be resumed with any prospect of advantage.

For the mathematical investigations relative to the figure of lenses, and to spherical aberration, see the articles and  in this Supplement.(.)  ACKERMANN, , a very learned physician and professor of medicine, was born at Zeulenrode in Upper Saxony, in the year 1756. Having acquired the rudiments of his medical education under the tuition of his father, who was also a physician, he proceeded to Jena and to Gottingen, and studied under Baldinger and Heyne. On quitting the latter university, he established himself in practice at Stendal, the numerous manufactories of which place enabled him to contribute many important observations to the translation of Rammazzini’s Treatise of the Diseases of Artificers, which he published in 1780-83. After practising here several years, he was appointed public Professor in ordinary of medicine, in the university of Altorf in Franconia, which office he continued to fill with great repute to the time of his death, which took place in 1801. All Dr Ackermann’s works display great erudition. To the history of medicine he contributed many valuable articles; the disquisitions, in particular, on the lives and writings of Hippocrates, Galen, Theophrastus, Dioscorides, Aretæus, and Rufus Ephesius, which he furnished to Harles’s edition of Fabricius’ Bibliothæca Græca, are justly esteemed as masterpieces of critical research. As a practitioner he appears to have possessed no mean talents for observation; though he has been accused, and, it must be acknowledged, not without reason, of betraying occasionally a predilection for antiquated hypotheses. Besides various translations of English, French, and Italian medical authors, which were published, for the most part, previously to his removal to Altorf, the following works have appeared under his name:—1. De Trismo, Commentatio Medico. 8vo, 1775.—2. De Dysenteriæ Antiquitatibus liber bipartitus. 8vo, 1777.—3. Ueber die Krankheiten der Gelehrten. 8vo, 1777.—4. The Life of John Conrad Dippel, in German. 8vo, 1781.—5. Parabilium Medicamentorum Scriptores Antiqui: Sexti Placiti Papyriensis de Medicamentis ex Animalibus; Lucii Apulei de Medicamentis ex Herbis, cum Notis. 8vo, 1788.—6. H. D. Gaubii Institutiones Pathologiæ Medicæ, cum Additamentis, J. C. G. A. 8vo, 1787.—7. Regimen Sanitatis Salerni, c. Studii Medici Salernitani Historia Præmissa. 8vo, 1790.—8. Institutiones Historiæ Medicinæ. 8vo, 1792.—9. Institutiones Therapiæ Generalis. 2 tom. 8vo, 1793-95.—10. Handbuch der Kriegsarzneykunde. 2 tom. 8vo, 1795.—11. Opuscula ad Historiam Medicinæ pertinentia. 8vo, 1797.—12. Bemerkungen über die Kentniss und Kur einiger Krankheiten. 8vo, 1794-1800.—13. Pathologische-Praktische Abhandlung über die Blähungen, für Aertze und Kranke bestimmt. 8vo, 1800.(.) ACOSTA, a celebrated Spanish author, was born at Medina del Campo, about the year 1539. In 1571, he went to Peru as a Provincial of the Jesuits, having entered into that society in his fourteenth year. After a residence in America of seventeen years, he returned to his native country, and became in succession visitor for his order of Arragon and Andalusia, superior of Valladolid, and rector of Salamanca; in which city he died in February 1600.

About ten years before his death, he published at Seville, in one volume quarto, his valuable work entitled Historia Natural y Moral de las Indias. The two first books of this history were written during his residence in Peru, and were published separately after his return to Spain, in the Latin language, with this title: De Natura Novi Orbis, libri duo. He afterwards translated them into Spanish, and added to them other five books, the whole composing a connected work, under the first mentioned title. This work, which has been translated into all the principal languages of Europe, is written on a regular and comprehensive plan. The five first books are employed upon the physical geography and natural history of that portion of America which had been conquered or discovered by the Spaniards; the fifth and sixth upon the manners, religion and civil institutions of the inhabitants; and the last, upon the history of the Mexicans, from their origin till the period of their subjugation. Dr Robertson pronounces Acosta, “an accurate and well-informed writer.” Among other things, he treats the subject of climate in a more philosophical manner, than could have been expected in a writer of that age, and of his order. “He was the first philosopher,” says the eminent author just quoted, “who endeavoured to account for the different degrees of heat in the old and new Rh