August 28, 1885.] 



SCIENCE. 



163 



descendant of an ape, which would be only generi- 

 cally separable from the chimpanzee and the gorilla; 

 and that while the last two are little modified de- 

 scendants from a common stock, man's structure, in 

 some respects, has been much modified, — but even 

 man's deviation is mostly superficial and psycholo- 

 gical. Theo. Gill. 



Washington, Aug. 5. 



[We meant, by the statement which Dr. Gill criti- 

 cises, that the immediate exact ancestors of man are 

 not known to paleontologists; and that the morpho- 

 logical evidence has not yet been so fully worked 

 over as to afford definite conclusions as to the evolu- 

 tion of man. The elucidation of the exact affinities 

 of man with various primates still awaits exhaustive 

 study: that he is related to the anthropoid apes, is, of 

 course, well established; but that he is more closely 

 related to them than to any other primates has still 

 to be proven. In suggesting a relationship between 

 man and the monkeys, we meant rather to propound 

 a question, than to advocate a conclusion. In reality, 

 there is probably no essential difference between Dr. 

 Gill's opinion, and the suggestion emitted in our com- 

 ment, which our critic seems not to have understood 

 as we intended. — Ed.] 



A mad stone. 



Your question, Mr. Editor, having regard to Mr. 

 Sampson's letter concerning a ' mad stone,' ' how did 

 such a superstition arise ? ' admits of a ready answer. 

 Many a porous stone, in good capillary condition, can 

 suck a icound, not so effectively, perhaps, as the lips 

 of Queen Eleanor, but still with considerable power. 

 This fact is especially true in case the stone has been 

 moistened so that close contact between it and the 

 body may be secured, as well as continuity of the 

 fluids, and evaporation from the external surface of 

 the stone, to actuate the capillary flow. Familiar ap- 

 plications of the principle are seen when the country- 

 boy puts a dab of mud upon the spot where a hornet 

 has St ung him to compose the pain ; and when the 

 housewife uses French chalk, or soap-stone dust, or 

 wet plaster-of-Paris, or, better yet, clay moistened 

 with naphtha, ether, or oil of turpentine to draw out 

 a grease-spot from clothing or from the floor. Thus 

 much for the basis of the ' superstition.' It is as- 

 suredly easy to conceive withal that ' mad stones ' 

 may have existed of such chemical composition, or 

 charged with such chemical substances, that they 

 could act as germicides as well as absorbents. In- 

 deed, we have already in that most sovereign of balms, 

 powdered chalk for a mosquito bite, something so 

 nearly akin to the ideal mad stone, that your corre- 

 spondent was more than justified in according to the 

 matter his portion of that careful attention which 

 Arago did extol. F. H. Stoker. 



THE KONGO FREE STATE. 



Mr. Stanley has given a history of the 

 planting of this state, its growth to the pres- 

 ent time, and the recognition of its flag and 

 sovereignty by the powers of Europe and 

 America, at the Berlin conference. His book 

 has been supplemented by reports from French 

 and Portuguese travellers ; from Lieut. Cam- 

 eron of the English arm}', who crossed Africa 



from the east to the west a little below the 

 valley of the Kongo ; from Mr. W. H. Tisdel, 

 the agent sent by our government to the Kon- 

 go ; and from Admiral English, commander of 

 our fleet on the African coast. These reports, 

 though somewhat conflicting, can be recon- 

 ciled, and the truth ascertained. 



The Kongo free state, by the terms of the 

 Berlin convention, controls a narrow strip on 

 the northern banks of the Lower Kongo, from 

 the ocean to Stanley Pool ; thence the terri- 

 tory extends north-east to between the fifth and 

 sixth degrees of north latitude, and south be- 

 low the eleventh degree of south latitude, and 

 east to within a few hundred miles of the In- 

 dian Ocean, including in its limits nearly all 

 the water-shed of the Kongo and its branches. 



The river is navigable from the ocean to 

 Vivi. Between Stanley Pool and Vivi, 235 

 miles, there is a fall of 1,200 feet, with 80 

 miles of navigable water between the falls. 

 There are a large number of navigable branch- 

 es running into the Kongo, and steam-launches 

 have sailed on the Kongo and these branches 

 nearl}' 1,500 miles. Mr. Stanly estimates, 

 indeed, that there are over 5,000 miles of 

 uninterrupted navigation on them ; and that, 

 in addition, the navigable waters of other trib- 

 utaries would probably bring the total to about 

 20,000 miles : these estimates cannot be fully 

 relied upon, but there is suflficient evidence to 

 prove that the navigable w^aters of the Kongo 

 exceed those of any other river in the world. 



The land in the eastern part of the water- 

 shed of the Kongo is between 4,000 and 5,000 

 feet in height, faUing at first pretty rapidly, 

 and then more gradually, into the great valley 

 of the Kongo, about 1,500 feet above the sea- 

 level. 



As the river rises in the east, runs to the 

 west near the Equator, its valle}^ has nearly 

 the same climate, growing more temperate 

 towards the sources of the river. The whole 

 area is abundantly supplied with rainfall. 



The outlets for the trade of this vast region 

 have hitherto been south through the Portu- 

 guese territory to the Atlantic Ocean at Ben- 

 guela, or else north-west through the French 

 possessions to the valle}^ of the Ogowe. The 

 Kongo oflfers the shortest route to the ocean, 

 but the river has cut its way through the 

 chains of mountains ; while the Kwilu Niadi, 

 in the territor}^ of the association, and the 

 Ogow^, follow natural valleys, and reach the 

 ocean b}^ longer and easier routes. 



Mr. Stanley constructed a road around these 

 falls. It crosses a succession of valleys and 

 steep hills, some one thousand feet in height. 



