312 



SCIENCE, 



[N. S. Vol. IV. No. 



entered through, the tip of a subterranean dome 

 by means of ladders, and the lowest level of the 

 cavern is 250 feet below the entrance. There 

 are a number of fine domes, and passageways 

 miles in extent. The effect is said to be very 

 fine, as the crystals have not yet been injured 

 by the smoke of lamps and fireballs. 



American students will be interested in 

 an article in Science Progress for August, 

 on ' Petrology in America, ' by Mr. Alfred 

 Harker, of St. John's College, Cambridge. The 

 author gives an account of the results of some 

 thirty-seven investigations. The author writes: 



" The material for study offered to the American 

 geoIo2;ist is rich in many respects, and perhaps in no 

 branch richer than in petrology. The vast tracts of 

 Tertiary lavas along and to the west of the Rocky 

 Mountains, the peculiar • igneous rocks on the east 

 side of the great watershed, the varied series of lavas, 

 tuffs, and intrusive masses in the Palaeozoic and older 

 formations of the Eastern States, the extensive areas 

 of igneous and other crystalline rocks in the Lake Su- 

 perior region, the Adirondacks, Canada, etc., all 

 present many points of interest, and much valuable 

 work has already been done in the description and 

 study of these rocks. These results we owe in large 

 part to the United States Geological Survey and that 

 of Canada, and to various State surveys ; Minnesota, 

 New York, Arkansas, Texas, etc. Besides this offi- 

 cial work, systematic petrographic research has been 

 carried on at several universities and colleges, such as 

 Johns Hopkins, Columbia College, Yale, the Univer- 

 sity of California, and others. ' ' 



Another paper of interest to American geol- 

 ogists in the same journal and also by a member 

 of St. John's College, Mr. Philip Lake, is on 

 ' The Work of the Portuguese Geological Sur- 

 vey.' The oflficial Communicagoef da Direcgao 

 dos Trabalhos geologicos de Portugal may be dif- 

 ficult reading for many (although a large part 

 of the memoirs has also been published in 

 French) and Mr. Lake's account of the recent 

 work of the survey, which is of very consider- 

 able importance, is thus opportune. 



M. Henri Moissan has reported to the Paris 

 Academy that he has found, in disintegrated 

 rocks from Brazil, microscopic diamonds, both 

 black and transparent, and that they were in 

 connection with graphite. 



Students of primitive culture are inclined to 

 attribute a wider and wider extension, as their 



knowledge of early conditions increases, to the 

 matriarchal system of the family. Prof. E. B. 

 Tylor, in the Nineteenth Century, reaches the 

 conclusion that it has existed, in either a com- 

 plete or a partial form, among about half of 

 known peoples of the lower culture. Atten- 

 tion should be called in this connection to an 

 important book on the subject by Mrs. Gamble^ 

 which was issued by Putnam two years ago. 

 Prof. Tylor attributes the decadence of the cus- 

 tom to the spread of exogamy, which latter 

 practice gave the tribes which adopted it an ad- 

 vantage on account of its cementing friendship 

 and preventing fighting among larger and larger 

 bodies of men. He mentions the curious fact that 

 a Methodist missionary among the Maoris has 

 lately been inculcating exogamy among his 

 people with this same end, and with very good 

 results. C. L. F. 



At the recent International Psychological 

 Congress at Munich, Mr. George M. Stratton, of 

 the University of California, reported some in- 

 teresting experiments on vision without inver- 

 sion of the retinal image. An optical instru- 

 ment with lenses appropriately arranged pro- 

 duced such an image, and at the same time 

 excluded from the eyes all rays except those 

 coming through these lenses. This instrument 

 was worn on the eyes without intermission 

 (except at night, when the eyes were blind- 

 folded) from three o'clock in the afternoon of 

 the first day until noon of the third day. The 

 experience was somewhat as follows : all visual 

 images seemed at first inverted and illusory. 

 The things themselves were thought of as be- 

 ing, not where now seen, but where they would 

 probably appear could normal vision be re- 

 stored. Later, however, the present visual 

 presentations seemed 'real.' Objects outside 

 the field of vision began to be mentally repre- 

 sented in terms of the new abnormal vision ;, 

 they were pictured as they would appear if the 

 present visual field were moved or widened to 

 include them. 



At the meeting of the Paris Academy of 

 Science on August 17th, M. Weinek exhibited 

 a further series of photographs of the moon, 

 the negatives having been in part taken at the 

 Lick Observatery and in part at the Observa- 



