94 



SCIENCE. 



[N. S. Vol. XVI. No. 394. 



15 cm. and a radiiis of curvature of 15 M. 

 This is the arrangement now being used. 

 "With this velocity, assuming a band can be 

 read to one thirtieth part, a distance of 

 only .3 cm. would show a velocity. The 

 rays during transit may be made to pass 

 within a tube which can be evacuated, con- 

 necting M and M'. Another arrangement 

 may be used when M is placed at a much 

 greater distance and is shown in the 

 annexed diagram. I and F are two lenses 

 whose foci are M and their conjugate foci 

 on each face of 31' respectively. 



It seems certain now that the wave- 

 velocity in different media, as well as in 

 vacuo, may be determined to a high degree 

 of accuracy and that too for any color. 



University of Nebraska. ^- B- BrACE. 



PREHISTORIC PORTO RICO.* 

 It has been customary for the Vice- 

 President of this Section of the Associa- 

 tion to present in his retiring address cer- 

 tain general conclusions to which he has 

 been led by his own special studies or those 

 of his contemporaries. But it has not been 

 regarded as out of place for him to outline 

 new and promising fields of research or to 

 indicate lines for future development of 

 our science. 



Late historical events have brought into 

 our horizon new fields for conquest and 

 opened new vistas for anthropological 

 study. In the last years the political 

 boundaries of the United States have been 

 so enlarged that we have come to be re- 

 garded a ' world power, ' and with this 

 growth new colonies beyond the seas now 

 form parts of our domain. With this new 

 epoch certain broad scientific questions 

 have come to present a special claim on 

 our students, and we have been brought 

 * Address by the Vice-President and Chairman 

 of Section H, for 1901, at the Pittsburgh meeting 

 of the American Association for the Advancement 

 of Science. 



closer than ever before to problems con- 

 cerning other races of man besides the 

 North American Indian. Great fields of 

 work attract our ethnologists to the far 

 East and the islands of the Pacific, and 

 these new problems will occupy our atten- 

 tion with ever-increasing interest in years 

 to come as anthropology advances to its 

 destined place among sister sciences. It is 

 natural and eminently fitting that atten- 

 tion at this time should be directed to some 

 of the new anthropological problems before 

 us, and I have chosen as a subject of my 

 address, 'Prehistoric Porto Rico,' and the 

 Antillean race which reached its highest 

 development in our new possession in the 

 West Indies. 



Among all the acquisitions which came 

 to the United States by the Treaty of Paris, 

 Porto Rico is preeminent from an anthro- 

 pological point of view. Fourth in size of 

 the Antilles, it is the most centrally placed 

 of a chain of islands reaching from Florida 

 to the coast of South America. Before the 

 coming of Coluinbus there had developed 

 in these islands a citlture sufficiently self 

 centered to be characteristic, and our new 

 possession was the focus of that culture. 

 Here was found a race living in an insular 

 environment exceptional on the Western 

 Hemisphere. If as the great anthrogeog- 

 raphers insist anthropological problems 

 are simply geographical in their final anal- 

 ysis, where can we find a better opportu- 

 nity to trace the intimate relationship of 

 man's culture and his surroundings? Where 

 was there on the American continent at the 

 time of its discovery a people less affected 

 by contact with other cultures or more 

 truly the reflection of climatic conditions? 

 It may be truly said that important 

 questions regarding migrations of the 

 early inhabitants of the American conti- 

 nent are intimately related to the cultural 

 character of the prehistoric race which 



