TUNIS 



5901 



TUNNEL 



LOCATION MAP 

 This little country, border- 

 ing: the Mediterranean Sea, 



* 8 a very Small part Of the 



continent of Africa. 



TTJ ' NIS , a French protectorate on the Medi- 

 terranean coast of Africa, occupying the most 

 northerly portion of the continent. It was one 

 of the old Barbary States, and has been under 

 the pVotection of France since 1883. Tunis is 

 bounded on the 

 north and east 

 by the Mediter- 

 ranean, on the 

 >y Constan- 

 tine, a depart- 

 ment of Algeria, 

 and on the south 

 liy Tripoli and 

 the Sahara Des- 

 ert. It has an 

 area of about 48,- 

 000 square miles, 

 about that of the 

 state of Louisi- 

 ana, and its popu- 

 lation is esti- 

 mated to be 1,780,527, slightly less than that of 

 the American state. The majority of the in- 

 habitants are Bedouin Arabs and Jews, but 

 French, Italians, Anglo-Maltese, Spaniards, 

 Greeks and Turks are found in considerable 

 numbers. 



northern half of the country' is a plateau, 

 enclosed on the north and south by the Little 

 Atlas and the Great Atlas mountains, and the 

 southern half is a continuation of the Sahara. 

 The plateau region in the northern part con- 

 tains the principal river, tin Mejerda, as well 

 as many smaller streams, and is the chief agri- 

 cultural district ; the southern part is a treeless 

 plain covered with esparto grass. In the upper 

 part of the Sahara region the date palm flour- 

 ishes, for the land is irrigated by water from 

 many hot springs. All of the remaining desert 



region l- :i I. iiTi-n WSjfo 



The fertile area of Tunis has been well de- 

 veloped by European colonists, many of whom 

 own or have leased large estates. About 1.125,- 

 000 acres arc devoted to wheat, and nearly as 

 many to barley, and there is also a profitable 

 >f oats. Over 6,000,000 gallons of olive 

 oil are produced each year from the fruit of 

 nearly 12,000,000 trees, and in the desert region 

 there arc over 2,000,000 date palms. Other 

 products include almonds, oranges, lemons, 

 henna and cork. 



Stock raising and mining arc oth 

 of considerable importance. The produ* 

 phosphates is increasing every year, and lead, 

 line and iron are also mined in profitable quan- 



tities. The natives engage in fishing, spinning 

 and weaving wool, carpet weaving and saddle 

 making, and in the manufacture of matting. 

 slippers and pottery. The country has over 

 1 ? 400 miles of railway and about 2,000 miles of 

 good carriage roads. In normal years there is a 

 thriving import and export trade, chiefly with 

 France. Tunis, a city of about 164,600 inhabit- 

 ants, is the seat of government. It lies about 

 three miles from ancient Carthage. J.B.C. 



Consult Wartegg*s Tunis: The Land and the 

 People. 



Related Subject*. The reader who la Inter- 

 ested in this discussion of Tunis may consult the 

 following articles In these volumes: 

 Barbary States Date and the Date Palm 



Bedouins Sahara 



Carthage 



TUNNEL, tun' el, an underground passage, 

 piercing mountains or hills or passing under 

 the beds of rivers. Engineers once avoided the 

 construction of tunnels because of the expense, 

 but of late years many difficult engineering 

 feats have been undertaken in order to 

 straighten railway rights of way and to lessen 

 running time. Tunnels are considered by engi- 

 neers as of two kinds those driven through 

 rock and those excavated in soft earth. Rock 

 offers a tough resistance to tunneling, but it 

 has the advantage of requiring usually no sup- 

 port. The rock is drilled to form pockets, in 

 which are placed charges of high explosive, 

 which is then discharged by means of au elec- 

 tric spark. The shattered fragments of stone 

 are removed as the work progresses. Four of 

 the greatest tunnels in the world, the Alpine 

 tunnels of Mont Cenis, Saint Gotthard, Arlberg 

 and Simplon, were blasted out of solid rock. 

 When a tunnel is driven through soft earth or 

 under the mud of a river bed, it is necessary to 

 support the soil above to prevent caving. This 

 is accomplished by supporting the roof of earth 

 with u sheath of timbers or steel, about which 

 cement is poured and allowed to harden. 



In the construction of submarine tunnels the 

 most serious difficulty to U- overcome is the 

 inflow of water. Only in cases where the 

 lies far beneath the bed of the stream is this 

 not a serious problem for the engineer. The 

 situation is met by the use of the compressed- 

 air <>r the shield system; sometimes the two are 

 used in combination. By the compressed-air 

 method the pressure of the inflowing water is 

 checked by compressed air in the end of the 

 tunnel where the work is going on. Th< <th -r 

 system takes its name from the ingenious me- 



