892 



SCIENCE. 



[N. S. Vol. XIX. No. 493. 



Exhibition of the Series of Foot Bones Illus- 

 trating the Evolution of the Camel, Re- 

 cently Installed in the Hall of Vertebrate 

 Paleontology of the American Museum, of 

 Natural History: W. D. Mathew. 

 This series corresponds to that illustrating 

 the evolution of the horse, and is almost 

 equally complete. 



It shows the derivation of the camel from 

 small primitive four-toed ancestors vehich are 

 exclusively North American in habitat. The 

 earliest known ancestors are tiny animals no 

 larger than a rabbit. The camels reached their 

 maximum size and abundance in the Plio- 

 cene epoch, when they were much larger than 

 the modern camels. Then they spread to the 

 other continents, disappeared entirely from 

 North America, and became smaller in size 

 and far less numerous in species elsewhere. 



Some Erosion Phenomena in St. Vincent and 

 Martinique: Edmund Otis Hovey. 

 In this paper the author showed lantern 

 slides from some of the photographs taken by 

 him in those islands in 1902 and 1903, for the 

 American Museum of Natural History, which 

 illustrated the development of new drainage 

 systems and the reinstatement of old channels 

 in regions which were most thickly covered 

 with ejecta by the 1902 and 1903 eruptions of 

 the Soufriere and Mont Pele. 



The principal paper of the evening was : 



Some of the Localities in France and Eng- 

 land where Monuments of the Late Stone 

 and Bronze Ages have been Found: J. 

 Howard Wilson. 



In considering the subject of these stone 

 monuments, the author confined himself to 

 those found in northern France and southern 

 England, and especially the great groups near 

 Carnac in Morbihau, and the well-known 

 temples of Stonehenge and Avebury, in Wilt- 

 shire. 



The monuments were divided according to 

 type into several classes, and a description 

 of each of these given briefly with their com- 

 parative ages and the probable pui-poses for 

 which they were constructed. Legends con- 

 cerning these monuments were cited, and men- 

 tion was made of the superstition and venera- 



tion with which they have been regarded by 

 some of the more ignorant and conservative 

 peasants, causing the worship of stone to be 

 Ivcpt up to the present day in some remote 

 districts. 



Before closing the paper, attention was 

 called to the engineering skill required in the 

 placing and erection of some of the monu- 

 ments and the early age at which it made its 

 appearance. 



The paper was followed by slides showing 

 photographic views of some of the most fa- 

 mous monuments, maps and drawings of sev- 

 eral of the curiously engraved stones. 



Edmund Otis Hovey, 



Secretary. 



DISCUSSION AND CORRESPONDENCE. 



THE COMPLEX NATURE OP THORIUM. 



To THE Editor of Science: The following 

 appeared in Nature, April 28, p. 606 : 



THE COMPLEX NATURE OF THORIUM. 



With regard to several letters on thorium and 

 its complex nature that -appeared in Nature of 

 March 24 and 31, April 7 and 14, and in which 

 my name is mentioned, I take the liberty of adding 

 a few remarks, having had ten years' experience "in 

 working with thorium. 



In 1897, at a meeting of the British Association 

 in Toronto (Canada), I read a paper in which I 

 pointed out that spectrum evidence proves the com- 

 plex nature of thorium. 



In 1898 {Ghem. 8oc. Trans., p. 953) I isolated 

 from some thorium fractions an earth with an 

 atomic weight of 225.8 (tetrad). Knowing the 

 difficulties of the separation'of rare earths (I have 

 been engaged in this kind of work since 1878), and 

 not wishing to publish a premature conclusion, I 

 did not declare this to be a novel constituent of 

 thorium, but said that foreign earths were present, 

 in spite of the fact that the reaction used ought 

 to have separated them. 



In 1901 I published another short paper (Proc. 

 Chem. Soc, March 21, 1901, pp. 67-68), in which 

 I said that " my experiments may be regarded 

 as proving the complex nature of thorium. 

 Thorium was split up into the Th" and ThP. 

 With TliP I obtained so low an atomic weight as 

 i2" = 220. The fractions Tha gave by the anal- 

 ysis of the oxalate, though it was prepared by 

 pouring the thorium salt solution into an excess 

 of oxalic acid, in order to avoid the formation of 



