May i8, 1888.] 



SCIENCE. 



2^5 



Thus she was enabled to ascend the rapids. Three miles far- 

 ther up the river another rapid similar to the last was found, and 

 ascended in the same way. The next obstacle was by far the most 

 formidable one. Several islands situated in the river are connected 

 with the banks by rocks, over which the river falls. Here the 

 ' En Avant ' had to he unmounted and unloaded, and the hull was 

 hauled up the fall with great difficulty. Captain van Gele describes 

 this region as follows : — 



"The country is beautiful. The banks of the river are bordered 

 by Wills of gentle slope, with woods and prairies, plantations of 

 bananas, and fields of maize. Most of the villages are situated on the 

 slopes of the hills. Seen from afar, the huts give the impression of 

 Swiss cottages. If there were herds of cattle grazing on the prairies, 

 the illusion would be complete. The country seems to be of great 

 fertility, the grass attaining in some places a height of twenty feet. 



" The fronts of the villages situated on the banks of the river are 

 fortified by stockades. On high trees of Cottonwood, guards are 

 stationed in rudely constructed huts, which have given rise to the 

 legend of aerial villages. I have not seen any manioc or palms in 

 this district, while bananas, sugar-cane, and maize abound. Up 

 to the third rapid the natives are of the same type as those living 

 farther south on the river. Their heads are shaved, and their heavy 

 mustaches give them a military air. Their faces are not tattooed. 

 We were very kindly received by this people. Above the third 

 rapid a new tribe was met with, — the Bakombe, who are said to 

 occupy a great part of the territory between the Obangi and Kongo. 

 They have a very remarkable fashion of dressing their hair. Some 

 wear enormous chignons ; others, forms similar to those worn by 

 the Mombuttu ; still others, long and slender tresses, sometimes as 

 long as six feet." 



At the last rapid the waters of the river come from the north- 

 east. The view is grand. The river is about twenty-eight hun- 

 dred feet wide, and free from obstacles. Farther east its course 

 was found to be westerly. No tributaries were discovered above 

 the rapids. On the northern bank the country is level, while in the 

 south a few low hills may be seen. Although not a single house is 

 seen from the steamer, the country is densely inhabited, numerous 

 villages being situated a few hundred steps distant from the banks 

 of the river. The latter are called ' Dua' by the natives. There are 

 numerous islands, most of which are inhabited and cultivated. 

 Captain van Gele states that the country is one of great fertility, 

 and that more provisions were offered him than his party was able 

 to consume. Beautiful work in iron is made by the natives, while 

 ivory seems to be little valued. It is worth remarking, however, 

 that it is used for labrets worn in the upper lips. 



At Bemay a new rapid was met, which, however, was passed by 

 the help of the natives. A few miles above Setema, the first tribu- 

 tary, the Bangaso, was seen. It is a remarkable fact that neither 

 on the north nor on the south side are there any tributaries. The 

 same scarceness of tributaries is observed on the Kongo : therefore 

 it seems probable that the region between the Shari and the Chuapa 

 is throughout occupied by rivers running east and west. After the 

 Bangaso was passed, a new tribe was met, the Yakoma. who at- 

 tacked the steamer. On Jan. I, 1888, the 'En Avant,' which 

 steamed along the north bank of the river, met aline of rocks form- 

 ing a rapid. The steamer separated from the canoe in order to search 

 for a pass. Immediately numerous natives attacked the canoe. At 

 the same time the steamer struck a rock, and it was necessary to 

 unload and to make a landing among the hostile natives. Lieuten- 

 ant Lienart, who was charged with this task, was kindly received, 

 but only to be attacked the more vigorously later on. In the ensu- 

 ing struggle two of his men were killed. After all, the steamer was 

 reloaded and repaired on an island ; but the hostility of the natives, 

 and the fact that the water of the river was falling rapidly, made it 

 necessary to return at once. The expedition had reached 21" 55' 

 of longitude, the distance to the farthest point of Junker being some 

 seventy miles. It is in this unknown stretch that the Mbomo emp- 

 ties itself. The return was effected without casualties. 



The important result of this expedition is to show that the Welle 

 belongs to the Kongo system ; for it would be unreasonable to doubt 

 its identity with the Obangi any longer. There is also some pros- 

 pect of having the western boundary of the Kongo basin explored 

 ere long. Two German expeditions are pushing eastward from 



Kameroons, while the English missionary Brooke is ascending the 

 Obangi, intending to strike north-westward from Zongo. 



SCIENTIFIC NEWS IN WASHINGTON. 



The Work of the United States Fish Commission on the Atlantic Coast ; 

 the Migrations of Fishes governed by the Temperature of the 

 Water ; Isothermals to be constructed. — A Great Work by the 

 Bureau of Ethnology ; the Dictionary of North American Indian 

 Tribes completed. — Shall the Arid Lands be reclaimed? a Mag- 

 nificent Undertaking. ^ A New Law for the United States Fish 

 Commission proposed. 



The Work of the ' Grampus.' 



One important fact has been established by the investigations of 

 the United States Fish Commission, and that is, that the move- 

 ments of the great masses of food-fishes that visit the bays and 

 rivers of this country in summer are not governed by a desire to 

 return to the localities where they were born, nor by the scarcity or 

 abundance of food, but by the temperature of the water in which it 

 is suitable for them to spawn. For instance : the shad never enter 

 one of our bays or rivers in the spring until its temperature has be- 

 come 60° F. Then they pass into the rivers, and up towards their 

 sources, always seeking the warmer waters. They move up stream 

 when the difference of temperature is so slight that it can only be 

 detected by the use of a differential thermometer ; but so sensitive 

 are they with their whole bodies immersed, that they easily dis- 

 cover the direction in which the warmer water lies. 



The reason why the attempt to plant shad on the Pacific coast 

 failed is now known. Large quantities of little shad were planted 

 by the United States Fish Commission in the Sacramento River. 

 Very few of them returned, and all the attempts to stock the Pacific 

 coast waters with shad have resulted only in distributing the fish 

 in small numbers along the coast to Vancouver's Island, a distance 

 of sixteen hundred miles. A few now enter the small rivers that 

 have their sources near the coast, but nowhere do they show a 

 disposition to come in great bodies, as on the Atlantic coast. The 

 explanation is, that the bay is fed by rivers rising in the mountains, 

 and bringing down melted-snow water, so that its temperature 

 during the spawning-season for shad is only 55° or 60°. Fishes 

 that were placed in the Sacramento River one year, therefore, never 

 come back. If they approach the bay, they find it too cold to pass. 



California salmon, on the other hand, require a temperature of 

 from 40° to 45° for spawning. As they go up the rivers from the 

 Pacific Ocean, the water becomes colder, and they finally reach that 

 which is just right. But young California salmon placed in East- 

 ern rivers do not become acclimated ; in fact, they rarely come 

 back. Of fifteen million young ones so planted by the United 

 States Fish Commission, not more than three or four have ever 

 been caught or seen in the rivers it was desired to stock. The 

 water of the rivers is warmer as they go up stream, and they 

 avoid it. The attempt to stock the rivers of southern Europe flow- 

 ing into the Mediterranean Sea with California salmon has been 

 successful for two reasons : they have not been able to get out of 

 the Mediterranean and find other spawning-places if they desired ; 

 and they have found streams which, being fed by melting snows in 

 the mountains, furnish the conditions sought. 



Menhaden never enter rivers the temperature of which is below 

 50°. These fishes visited the coast of Maine in great numbers for 

 forty years, but in 1878 suddenly disappeared. The same year the 

 mackerel did not enter the Bay of Fundy. It is now believed that 

 this strange phenomenon was caused by a change in the tempera- 

 ture of the water. 



These facts being established, it becomes vei7 important, from 

 an economic point of view, to ascertain what changes take place 

 during the season in the temperature of the ocean off our coast 

 and of the bays enclosed by it, to plot isothermals, and to lay down 

 upon charts the migrations of these isothermals as the season ad- 

 vances. It is believed, that, when this is done, the migrations of 

 our summer food-fishes will also be discovered, and that their 

 movements can be accurately predicted. This work has been as- 

 signed to the 'Grampus' for the present season. Her field will 

 be from the capes of Virginia north. She will make careful obser- 



