November 14, 1S84. 



SCIENCE. 



To 9 



with secure establishment, and even dared, in 

 1861, to excommunicate the sultan, Abd el- 

 Mejid, for failing to respect its pretensions. 



The operations of the order are carried on 

 by a system of graded officers, priests, and 

 missionaries, which, as well as their adroit and 

 varied methods, strongly recall the marvellous 

 organization once attributed to the order of 

 Jesuits. Xor has the result been less success- 

 ful. Tribes alien and unreceptive, rulers cold 

 or jealous, populations indifferent or con- 

 temptuous, have been won over and firmly at- 

 tached to the order. The hard-worked native 

 transfers his field to the society, preferring to 

 lay up treasures in heaven. The fraternity 

 digs wells in the desert, revives withered oases, 

 protects its votaries from the nomad thieves of 

 the Sahara, buys, instructs, and frees slaves, 

 and sends them to their distant homes as mis- 

 sionaries, with astonishing results. 



The headquarters of the order are at the 

 zaouia, or convent, of Jarabub, founded in 

 1861. on the 30th parallel, near the western 

 frontier of Egypt. Its population has increased 

 marvellously during the last ten years. The 

 place was originally a desert. The society built 

 reservoirs, began plantations, erected con- 

 vents ; and in 1880 the body-guard of the head 

 of the order was estimated to consist of four 

 thousand men and about two thousand slaves. 

 The metropolitan is the son of Sidi es-Senousi, 

 whose genius he would appear to inherit, and 

 is known as Sidi Mohammed el-Mahcli, having, 

 like the false prophet of the Sudan, assumed, 

 at his father's instigation, the title equivalent 

 to a Moslem messiah. The convent has be- 

 come an arsenal, possessing large stores of 

 arms and ammunition, and even fifteen cannon 

 purchased at Alexandria. Aid and comfort 

 are lavishly extended to those who have from 

 time to time revolted against France in 

 Algeria. 



Too wise to inaugurate as }*et the holy war 

 predicted of El-Mahdi, the head of the order 

 has, nevertheless, provided against external 

 aggression. Suspecting that its propaganda 

 may eventually rouse the arms of civilization 

 against it, it is said that there are constantly 

 kept at the zaouia of Aziat in C}Tenaica, for 

 example, five hundred camels with their har- 

 ness and equipments, drivers, etc., read}' at a 

 moment's notice to convey to the interior the 

 persons and property of the Senousian authori- 

 ties. The fraternity possesses one of the best 

 ports in North Africa, — Tobrug, — where an 

 illegitimate trade flourishes, and does not 

 want for manufactories of powder. 



France is. so far, the only civilized nation 



which has suffered directly from the policy of 

 the order. In Algeria most of the rebellions 

 of late years are attributed to the new propa- 

 ganda. The insurrections there have been im- 

 itated in the French district of Senegal. AVe 

 have already referred to the probable connec- 

 tion of the order with recent events in the 

 Sudan. 



We have refrained from entering into a mul- 

 titude of details which support the preceding 

 conclusions, and it is not necessary to recount 

 the different tribes and petty African states 

 which have gradually become converts to the 

 views of the fraternity. Enough has been 

 said, however, to indicate the unsuspected im- 

 portance of this new factor in the politics of 

 Africa. The blood of man}' explorers and 

 travellers bears testimony to the violence of its 

 fanaticism ; and neither the geographer nor 

 the anthropologist can regard with indifference 

 a movement which falls little short of that 

 which originally propagated the faith of Islam. 



W. II. Dall. 



THE RUBY-HILL MINES, EUREKA, NEV. 



Me. J. S. Curtis, whose report on the silver-lead 

 deposits of Eureka, Nev., is now in press, has pre- 

 pared for exhibition at the New-Orleans exposition, 

 by the U. S. geological survey, a model of the Ruby- 

 hill mines, from wdiich the largest portion of the 

 metals extracted in the Eureka district has been 

 taken. This model is eighteen inches in height, and 

 about four feet long by eighteen inches wide. It is 

 composed of glass plates horizontally arranged at dis- 

 tances of one inch apart, each inch representing a 

 hundred feet, and the glass plate showing a section 

 at each mine-level in the body of the model, the 

 mine-levels being that distance apart. The upper 

 plates, however, are closer together, and are cut to 

 show the contours of the surface at distances of fifty 

 feet apart. 



On these plates the geological formations, three 

 in number (quartzite, limestone, and shale), all of the 

 Cambrian period, are colored with transparent colors. 

 The ore-bodies, occurring only in the limestone and 

 of tertiary or pre-tertiary age, are very irregular in 

 form, and are shown by opaque red paint; while the 

 mine-workings, shafts, tunnels, etc., are represented 

 in opaque black paint. The effect of the model is as 

 though a skeleton of the mine-workings and ore- 

 bodies were seen suspended in a solid glass mass, the 

 coloring of the geological structure not interfering 

 with the view, on account of its transparency. 



The dominant factor of the structure of Ruby 

 Hill is an extensive fault, which has determined the 

 present relations of the formations. The presence of 

 this fault is marked by a fissure filled in places with 

 rhyolite. This fissure also forms the hanging-wall of 

 the ore-zone. Above the water-level the ore is prin- 



