2 6o POPULAR SCIENCE MONTHLY. 



this part of the world, in spite of its great abundance. He found salt 

 mines in the heart of the desert near a place called Thegazza. For 

 the Soudanese salt has from time immemorial represented, and still 

 represents, the principal article of commerce and their most precious 

 commodity. The long depression in the western Sahara bearing the 

 name of El Djouf is a vast mine of rock salt. The salt mines of 

 Thegazza were abandoned in the sixteenth century for those of Taou- 

 demi, nearer Timbuctoo. The same explorer reports that even here 

 the houses are built of rock salt and roofed with camel skins. Under 

 a thin covering of sand the mineral is found in clearly marked layers. 

 It is dug out in large lumps and trimmed down to blocks about three 

 and a half feet long by one and one fourth feet in breadth. It looks 

 like bars of red or gray-veined marble, and as they come out of the 

 mine they are stamped with the trade-mark of the different contractors. 

 At Timbuctoo they are embellished with designs in black paint and the 

 name of some venerated chief is written on them in Arabic characters. 

 They are then bound round with thongs of raw leather so arranged as 

 to hold the parts together in case of fracture. The densest and whitest 

 blocks are most in demand, those veined with red being of an inferior 

 quality. Timbuctoo is the entrepot of the whole region lying south- 

 east as far as Lake Chad. There is nothing that the Soudanese pos- 

 sesses that he refuses to part with for a lump of salt. To these people 

 it is more valuable than gold itself. 



In ancient as well as modern times the partaking of salt with an- 

 other person was regarded as the symbol of friendship and hospitality. 

 Among the Slavic peoples it is still the custom to welcome the stranger 

 with a proffered gift of salt and bread; while in cases of dispute the 

 Arab is wont to appeal to the bread and salt he has eaten with his 

 adversary as proof of sincerity. The advice embodied in the injunc- 

 tion, 'Before you make a friend, eat a bushel of salt with him,' has 

 been proverbial from the remotest times. Both Aristotle and Cicero 

 refer to it as current in their time. An ancient commentator on 

 Homer says that salt is regarded as the symbol of friendship, par 

 excellence, either because it was offered to guests before anything else, 

 or because salt more than any other substance is a prophylactic against 

 decay. In Numbers certain offerings are enumerated as constituting 

 'a covenant of salt for ever before the Lord unto thee and thy seed 

 with thee.' Perhaps the custom of handing down the salt vessel from 

 generation to generation in Soman families has some connection with 

 the idea of incorruption. 



The word salt has impressed itself on our language in a curious 

 way in our term 'salary.' So necessary did the Bomans consider salt 

 to the efficiency of their armies that each soldier was provided with a 

 special ration of it, or with the means of providing it. This stipend 



