498 J^ANSAS CITY REVIEW OF SCIENCE. 



ion being a light copper-color. In intelligence they are also superior to other 

 tribes of Indians found in that region. Alligators of various sizes are found to 

 abound on the Ceni River, and they caused much annoyance by frequently steal- 

 ing provisions from the boat at night while the exploring party was encamped on 

 the bank. Insect pests were numerous. A species of sand-fly called the marnim 

 preyed upon them during the day and the mosquitoes stung them at night. They 

 were also subject to the attacks of the tabino fly, a- species of horse-fly of which 

 there are two varieties, one black and the other yellow. They are at about 

 latitude 10.50 south. From thence to the Amazon the marnim fly abounds. 



After reaching the Mamore River, October nth, Dr. Heath ascended that 

 stream 325 miles to Exaltacion, and from that point crossed the plains to Reyes. 

 From thence by rafts he ascended the Beni River to within ninety miles of its 

 source at La Paz, and covered the remaining distance on mules. Previous to 

 the discovery by Dr. Heath that the river was navigable the products of the re- 

 gion were transported to Arica and thence by sea around Cape Horn to Europe, 

 or otherwise across the pampas to the Mamore River, thence down the Madeira 

 to San Antonio, to which point steamers at present ascend. The Beni has an 

 advantage over the Mamore as a highway of commerce in having only one fall, 

 while the Mamore has five such obstructions. " Soon after the results of my ex- 

 plorations became known," said Dr. Heath, "the tide of commerce began to 

 seek the Beni route." All the commerce of Bolivia must ultimately pass to Eu- 

 rope by way of the Amazon and Beni Rivers. 



Dr. Heath said that within four years a railroad would be constructed from 

 San Antonio to the Beni River a short distance above its junction with the Ma- 

 more River. By this means the falls of the Madeira are avoided. The route 

 for commerce will then be from Reyes by steamer to where the railway taps the 

 river, then by rail to San Antonio and. from that place by steamer down the Ma- 

 deira to the Amazon and onward to the sea. 



As an instance of the impulse which the opening of the Beni River has given 

 to commerce, Dr. Heath mentioned that previous to the discovery that the river 

 was navigable 185 men were employed in collecting rubber gum. Soon after the 

 discovery was made 644 men speedily found employment at it. The price of the 

 gum before the exploration was $16 per 100 pounds delivered at Reyes; after the 

 exploration it was worth $25.60 at the point of collection. The 185 men collect- 

 ed on an average 104,000 pounds of rubber annually. 



"The supply of rubber," said Dr. Heath, "is sufficient to give employment 

 to 100,000 men, and as^soon as the chain of communication by steamer and 

 railway is completed that number of men will be engaged in that field of 

 labor. The rubber, though at present commanding only the same market price, 

 is of a slightly finer quality than that obtained at the old established districts be- 

 tween the falls and the mouth of the Madeira River and on the River Tapajoz 

 and other tributaries of the Amazon near Para. It possesses other more impor- 

 tant advantages over the older districts. The cUmate is healthy. There is an 

 .abundant supply of cheap labor at hand, the Indians obtained from the depart- 



