Page:Encyclopædia Britannica, Ninth Edition, v. 11.djvu/709

Rh the clergy not being enforced in England till, this paternity was considsred no disgrace, and our author in several passages of his writings refers to his father with much filial respect. Received as a mere child into the household of Robert of Bloet, bishop of Lincoln, Henry not only continued to enjoy the advantages of its culture and affluence till the bishop s death in, but he also secured the patronage and friendship of Alexander of Blois, who next succeeded to the see. There is reason to believe that he accompanied Alexander to Rome, probably in and, and it was to him that he dedicated his Historian Anglorum, which was issued four times during the author s life, and in the last form came down to the accession of Henry II. . The date of the author s death has not been preserved, but it is probable that the close of his life is approximately marked by the close of his history.

1em  HENRY, (1797–1878), an eminent American physicist, was born in Albany, the capital of the State of New York, on the 17th of December 1797. He received his education at an ordinary school, and afterward at the Albany academy, which enjoyed considerable reputation far the thoroughness of its classical and mathematical courses. On finishing his academic studies he contem plated adopting the medical profession, and prosecuted his studies in chemistry, anatomy, and physiology with that view. He occasionally contributed papers to the Albany institute, in the years 1824 and 1825, en chemical and mechanical subjects; and in the latter year, having been unexpectedly appointed assistant engineer on the survey of a route for a State road from the Hudson river to Lake Erie, a distance somewhat over 300 miles, he at once em barked with zeal and success in the new enterprise. This diversion from his original bent gave him an inclination to the career of civil and mechanical engineering; and in the spring of 1826 he was elected by the trustees of the Albany academy to the chair of mathematics and natural philosophy in that institution. In the latter part of 1827 he read before the Albany institute his first important contribution, &quot;On some Modifications of the Electro-Magnetic Apparatus.&quot; Struck with the great im provements then recently introduced into such apparatus by Mr William Sturgeon of Woolwich, he had still further extended their efficiency, with considerable reduction of battery-power, by adopting in all the experimental circuits (where applicable) the principle of Schweigger s &quot;multi- plier,&quot;^ that is, by substituting for single wire circuits, voluminous coils (Trans. Albany Institute, October 10, 327, vol. i. pp. 22&amp;gt; 23). In June 1828 and. in March 1829 he exhibited before the institute small electro magnets closely and repeatedly wound with silk-covered wire, which had a far greater lifting power than any then known. Henry appears to have been the first to adopt insulated or silk-covered wire for the magnetic coil ; and also the first to employ what may be called the &quot;spool&quot; winding for the limbs of the magnet. He was also the first to demonstrate experimentally the difference of action between what he called a &quot; quantity &quot; magnet excited by a &quot;quantity&quot; battery of a single pair, and an &quot;intensity&quot; magnet with long fine wire coil excited by an &quot; intensity &quot; battery of many elements, having their resistances suitably proportioned. He pointed out that the latter form alone was applicable to telegraphic purposes. A detailed account of these experiments and exhibitions was not, however, published till January 1, 1831 (Silliman s Am. Jour. Sci., xix. 400-408). Henry s &quot;quantity&quot; magnets acquired considerable celebrity at the time, from their unprecedented attractive power, one (August 1830) lifting 750 pounds, another (March 1831) 2300, and a third (1834) 3500.

1em 