118 



BAETH, HEINEICH. 



ing at the back of the sheet, and thus, through 

 an interposed strip of duplicating impression 

 paper, secures the imprint of the types. 



Mr. Hough acknowledges his indebtedness to 

 Mr. Thomas Simons for suggestions in connec- 

 tion with the mechanism, of which also certain 

 parts, as the screws, were constructed by Mr. 

 Charles Fasoldt, of Albany. Many details re- 

 specting its construction, management, the pro- 

 posed compensation for temperature, &c., are 

 necessarily omitted. Printed readings of this 

 barometer, while it was yet in a less perfect 

 form than at present, and as obtained during 

 six days of the close of April, 1865, deviated in 

 no case more than .005 of an inch from the in- 

 dications of a standard barometer (Fastre) during 

 the same period. Of the value of a perfectly 

 working instrument of this sort there can be no 

 question ; but it has already received practical 

 confirmation also in the curves afforded by its 

 working, and through comparison of these with 

 weather states, storms, winds, &c. In a private 

 letter, Mr. Hough states that he is enabled by 

 the character of the curves to predict with 

 great certainty gales of wind from 12 to 36 

 hours in advance ; and that it is, in fact, rather 

 by the character of the curve, in respect espe- 

 cially to regularity, and we may suppose direc- 

 tion also, than by the actual height of the mer- 

 cury, that weather states are indicated. In his 

 pamphlet, he shows how the essential parts of 

 the automatic mechanism can be applied to the 

 rain-gauge, to the thermometer, and to the ane- 

 mometer, printing in this last the direction of 

 the wind in degrees, and its force or velocity 

 in pounds or miles. 



For the description of a form of self-register- 

 ing barometer, and of a proposed mode of com- 

 pensating for temperature in the siphon barom- 

 eter, by terminating the two limbs of the in- 

 strument in conical chambers, the reader is 

 referred to an article entitled "Barometer," 

 in the American Journal of Science for Sep- 

 tember, 1865. 



BARTH, HEINKICH, a German traveller, ex- 

 plorer, geographer, and author, born at Ham- 

 burg, April 18, 1821, died at Berlin, November 

 25, 1865. He was a graduate of the University 

 of Berlin, where he developed a decided taste 

 for classical geography which led him upon the 

 completion of his studies to travel through the 

 countries bordering the Mediterranean. Having 

 made a tour through Italy and Sicily, he em- 

 barked in 1845 at Marseilles, and from Gibral- 

 tar passed over to Tangier, Africa. Proceeding 

 along the Algerian coast, he made excursions 

 into the interior of Tunis, Tripoli, and across 

 the sandy desert to Bengazi. On his journey 

 thence to Cairo, he was attacked by a band of 

 Arab robbers, whom he bravely resisted, but 

 was severely wounded, and lost all his effects 

 and papers. He continued his researches, at an 

 expenditure of his private resources to the ex- 

 tent of $14,000, and starting from Cairo trav- 

 elled in Egypt, Sinai, Palestine, Asia Minor, the 

 islands of the ^Egoaan Sea, and Greece. These 



travels occupied him for nearly three years, and 

 in 1849 he published, at Berlin, an account of a 

 portion of them in a work entitled Wanderun- 

 gen durch die. Kustenlander des Mittclsmeeres. 

 On the 8th of December of the same year, he 

 again sailed from Marseilles, having been (with 

 Dr. Overweg) appointed by the British Gov- 

 ernment scientific companion to Mr. James 

 Eichardson. then charged by the Foreign Office 

 with a political and commercial mission to Cen- 

 tral Africa. Starting from Tripoli on the 4th of 

 February, 1850, Dr. Barth and his companions 

 crossed the Great Desert amid much difficulty 

 and danger. Losing himself at one time in that 

 trackless waste, he remained twenty-eight hours 

 without water, preserving his life by drinking 

 his own blood. Both Mr. Eichardson and Dr. 

 Overweg succumbed to the climate ; the former 

 in March, 1851, and the latter in September 

 of the following year. Dr. B., however, suc- 

 ceeded in saying the papers containing an ac- 

 count of the expedition, and forwarded them to 

 England, where they were speedily published. 



After the death of his companions, letters ar- 

 rived from the British Government continuing 

 Dr. Earth's commission, and accompanied with 

 a supply of funds. Continuing his explorations, 

 he reached Timbuctoo in September, 1853, 

 where he was imprisoned nearly a year, and a 

 rumor reached Europe that he had fallen a vic- 

 tim to the tribes in that region. In the mean 

 time Dr. Edward Vogel, then an assistant of 

 the British royal astronomer, Mr. Hind, volun-. 

 teered to go to Dr. Earth's assistance with a 

 company of sappers and miners. They were 

 joined at Tripoli by Mr. Warrington, son of the 

 British consul at that place, who died at Kuka 

 soon after. After a painful interval it was an- 

 nounced to the world that Dr. Barth was living, 

 and when he returned to Tripoli in September, 

 1855, his explorations had extended over twenty- 

 four degrees of latitude and twenty of longitude, 

 from Tripoli in the north to Andamawa in the 

 south, and from Bagirmi in the east to Tim- 

 buctoo in the west, upward of 12,000 miles. 

 Not long after his return, an account of his ex- 

 ploration was published by him in England, in 

 five volumes 8vo, 1857-'58, under the title of 

 " Travels and Discoveries in Northern and Cen- 

 tral Africa," and was subsequently republished 

 in this country in three 8vo volumes. His nar- 

 rative is minute in its detail almost to tedious- 

 ness, but it shows him to have been an accurate 

 and careful observer. While it was in course 

 of publication he resided in England, but not 

 long after wards returned to Germany, where ho 

 superintended the fitting out of other exploring 

 expeditions to~Central Africa, and visited North 

 ern Africa once or twice in the interests of 

 geographical science. Soon after the death of 

 Von Eitter, he was appointed his successor in 

 the Chair of Geography in the University of 

 Berlin, and became also the editor of the 

 "Erdkunde," to which, as well as to Peter- 

 mann's "Mittheilungen," he had previously 

 been a large contributor. He had, during the 



