896 



SCIENCE 



[N. S. Vol. XXV. No. 649 



small photograplis reproduced in half tones 

 in the text give excellent ideas of the manner 

 in which many of the trees and shruhs appear 

 in their natural state. M. Bonnet has made 

 the most of the botanical material which was 

 saved, and the record of native names for the 

 various plants is remarkably full. 



The expedition started from Biskra and 

 traveled almost due south about 1,260 geo- 

 graphical miles to the settlement of Zinder, in 

 the Damergou country, when they diverged to 

 the east until Lake Chad was reached, pass- 

 ing round it by the north and east, whence 

 they followed up the river Chari in a south- 

 easterly direction, crossing from its head- 

 waters to the Obangwe, an affluent of the 

 Congo, dovra which they proceeded to the sea. 

 The rocks encountered in the northern Sahara 

 were largely: first, cretaceous limestones of 

 Cenomanian age; then Devonian and a little 

 Silurian, more or less interspersed with crys- 

 talline schists. In the middle of the Sahara 

 the schists and granites prevailed, mitigated 

 by patches of volcanic character. To the 

 Boutheast of Lake Chad, more volcanics were 

 encountered, and, on the upper reaches of the 

 Chari River the schists, granites and diorites 

 again occupied the field. Excellent views of 

 the rocky and sandy desert with its character- 

 istic dunes abound in the text. The first dis- 

 covery and recognition of Silurian rocks, with 

 Climacograptus, appears to be due to this ex- 

 pedition. M. Emile Haug has carefully 

 worked out the Paleozoic fossils as well as 

 the remains of some Cretaceous vertebrates. 

 Selachians, fishes and reptiles, including two 

 new species of Ceratodus, referable to the 

 Albian. 



The native Tuaregs of the northern Sahara 

 are well described by Foureau, who shows how 

 their predatory habits naturally result from 

 the state of semi-starvation in which they 

 exist, and which leads them to travel even 700- 

 800 kilometers to make a raid, of which the 

 chief result for them at best can be but the 

 securing of a few camels and a few full meals 

 of meat. They have an alphabet and system 

 of writing of their own, but very few of them, 

 those chiefly among the women, know how to 



use it. The correspondence and business of 

 the most wealthy among them is done chiefly in 

 Arabic, by Arab scribes from Touat, who act 

 as secretaries. Those who can write are fond 

 of inscribing the characters on rocks; and 

 few are the suitable blocks of smooth stone in 

 the vicinity of their trails which do not bear 

 some inscription. They are great and fluent 

 liars, but among themselves do not steal, and, 

 within the tribe, observe the law of the cacha 

 They are monogamists, and their women enjoy 

 great liberty, and possess powerful influence 

 which they seem not to abuse. 



The Tuaregs dress in voluminous garments. 

 They cover the whole body and head, and veil 

 the lower part of the face, usually with a 

 strip of blue cotton, so that the eyes alone are 

 visible. This practise, perhaps originally 

 adopted to shield the skin from the ardent 

 reflections from the arid soil, has become 

 almost a religious observance. The influx of 

 slaves and wives from the negro races to the 

 south, the Arab and Egyptian blood derived 

 from the east, have made these people almost 

 incredibly mixed in blood. Careless in their 

 observation of the rules of the Koran, regarded 

 almost as infidels by the orthodox Moham- 

 medan, they are, when it is a question between 

 them and strangers, fanatically bigoted 

 Moslems. 



M. Hanay has devoted much consideration 

 to the prehistoric remains of the stone age 

 collected by the expedition, many of which are 

 illustrated by admirable heliotypes. In his 

 summary the commander of the expedition 

 pleads for the native people that they should 

 be allowed to practise the rites of their reli- 

 gion in peace; and has very little to say in 

 favor of the results accomplished by the 

 French missionaries, in the regions to which 

 the latter have had access. 



On the whole the work is a mine of material 

 for the geographer, geologist, naturalist and 

 ethnologist, and reflects the highest apprecia- 

 tion of the labors of those who have succeeded 

 in bringing so arduous an expedition to a 

 happy and successful conclusion. 



W. H. Dall 



