December 12, 1884] 



SCIENCE. 



531 



pointed governors of the equatorial Nile basin. 

 They succeeded in stamping out the trade in 

 the province of Equator, which was annexed 

 to Egypt in Baker's time. This province was 

 inhabited exclusively by pure negroes ; while 

 Bahr-el-Gazelle, where Schweinfurth lived so 

 long, contained a large number of Arabs of 

 more or less pure blood. 



Baker and Gordon undoubtedly suppressed 

 the slave trade of the White Nile, so far as it 

 was carried on by water ; but how much the 

 poor slave was benefited is another question. 

 Probably not much ; for the overland march 

 through Darfar and Kordofan must have been 

 more destructive of life than even the voyage 

 in a crowded Nile nugger. 



One of the most powerful of these ruffian 

 kings of Bahr-el-Gazelle was Seebehr Rahama, 

 whose seribas were near the Darfur boundary. 

 It was during Schweinfurth' s stay in the Bahr- 

 el-Gazelle country that Seebehr attacked and 

 defeated some government troops who had 

 been sent to take possession of a portion of 

 southern Darfur. Seebehr himself then under- 

 took the conquest of that country. The Egyp- 

 tian government, thoroughly alarmed at his 

 growing power, sent an arm}' to co-operate, and 

 Darfur was annexed to Egypt. This was in 

 1874. 



Darfur, the land of the Fur, is situated be- 

 tween 9° and 16° north latitude, and 22° and 

 28° east longitude. Its area is about one hun- 

 dred and five thousand square miles. Very 

 little is known of the country ; but the following 

 facts, gleaned from Dr. Nachtigal's communica- 

 tion to the French geographical society in 1876, 

 maj' be of interest. The population, estimated 

 at about four millions, is as mixed as that of the 

 other central Sudan provinces. The Fur, who 

 live in the highlands, speak a language of their 

 own. They are stigmatized by Nachtigal as 

 proud, vain, cowardly, treacherous, and as dis- 

 agreeable as the Wadai on the west. They 

 are black, of moderate height, with regular fea- 

 tures, and were the ruling race in Darfur before 

 the coming of the Egyptians. There, as in 

 Kordofan, there are many mixed races, and a 

 large Arab population, especially in the north- 

 ern and central portions. It must be remem- 

 bered that these Arabs of the Sudan are not 

 true Arabs, but to a great extent merely Arab- 

 ized negroes. 



After Seebehr had conquered Darfur, he went 

 to Cairo for his reward ; but, instead of being 

 loaded with honors, and sent back as governor 

 of Darfur, he was made a pasha, and kept in 

 Cairo on a pension. His followers, led by his 

 son Suleiman, in accordance with a preconcert- 



ed arrangement, rebelled ; but Seebehr was not 

 sent to quell the rebellion, as he had expected. 

 The revolt was crushed by Gordon's able lieu- 

 tenant, the lamented Gessi pasha, who became 

 governor of Bahr-el-Gazelle. But upon Gor- 

 don's withdrawal, all power to do good was 

 taken from Gessi, and he resigned. 



In 1877 the khedive entered into an agree- 

 ment with England, in which it was stipulated 

 that the slave-trade should cease in lower Egypt 

 on Aug. 4, 1884, and in the Sudan five years 

 later. The rebellious spirit of the inhabitants 

 had been suppressed by Baker, Gordon, and 

 Gessi. It broke out again on the favorable 

 opportunity which the revolt of Arabi pasha 

 afforded. Mahomet Achmet, or El Mahdi, put 

 himself at the head of the movement. A 

 series of defeats was suffered by the govern- 

 ment troops. Then came the worst blunder 

 of all. A portion of Arabi's bashi-bazouks 

 were sent to the Sudan under the command 

 of Hicks pasha, a retired English army-officer. 

 At first they were successl'ul ; but, when they 

 attempted the invasion of Kordofan, they were 

 surrounded, and cut to pieces. The Mahdi and 

 his followers were supreme except in the im- 

 mediate vicinity of a few garrisoned towns. 

 It was at this juncture that Gordon was sent 

 by the English government to report on the 

 military situation in the Sudan. On his way 

 he stopped at Cairo, and was commissioned 

 governor-general of the Sudan without pay. 

 His doings there are not known. It will be 

 curious to see, whether when he again turns up, 

 he still adheres to the following opinion, which 

 he wrote just before setting out : "I am con- 

 vinced that it is an entire mistake to regard the 

 Mahdi as in any sense a religious leader : he 

 personifies popular discontent." 



NAVIGATION OF THE AIR. 1 



We have described in detail {Science, No. 80) the 

 experiment made at Chalais-Meudon on Aug. 9, when 

 for the first time a balloon returned to its point of 

 departure. 



In 1852 Mr. Henry Giffard, in a steam-screw bal- 

 loon, obtained a speed of about 4 metres a second. 

 In 1872 Mr. Dupuy de Lome, with a motor worked 

 by seven men, attained a speed of 2.8 metres; and 

 the Tissandier brothers, with the first balloon fur- 

 nished with an electric motor, a speed of 3 metres 

 in 1883, and of nearly 4 metres in 18S4. 2 Renard and 



1 From an article by Gaston Tissandier in La Nature, 

 Nov. 15. 



2 By an experimental trip on Sept. 26, 18S4, the brothers Tis- 

 sandier proved that their balloon could be brought back to its 

 starting-point in calm weather; but, through lack of funds, they 



