Geology and Natural History. 175 



num : are absorbed by the smallest layer of water : acting like 

 long heat waves. While they are absorbed by cold platinum 

 thej 7 easily penetrate red-hot platinum. These n-rays radiate 

 from the Nernst lamp long after this lamp is extinguished, and 

 silica exposed to the sun's rays show these rays. 



Dr. O. Ltjmmer calls attention to the physiological effects on 

 the retina produced by experiments similar to those of Blondlot, 

 and suggests that the ?i-rays are merely ghostly images produced 

 on the structure of the retina and its nerves by the method of 

 observation pursued by Blondlot. The phenomena observed by 

 the latter appear to be the result of the struggle between the 

 rods and cones of the retina in the effort to fix our vision in the 

 dark. — Deutsch. Physikalisch. Gesellsch., v Jahrg., Nr. 23. j. t. 



9. The Rowland Effect. — The magnetic effect of electric convec- 

 tion has been tested by Wilson, Adams and Pender and Eichen- 

 wald. In addition to these investigators is now Himstedt, who 

 publishes a quantitative investigation in the hope of adding 

 cumulative evidence. One series of trials gave for the value of 

 v, the ratio of the electrostatic to the electromagnetic units, 3*04; 

 and a second series, 2*99. Himstedt's experiments, therefore, 

 confirm Rowland's results. — Ann. der Physik, No. 1, 1904, pp. 

 100-123. J. t. 



II. Geology and Natural History. 



1. United States Geological Survey. — The following publica- 

 tions of the U. S. Geological Survey have recently been received : 



Monograph XLV. The Vermilion Iron -Bearing District of 

 Minnesota, by J. Morgan Clements. 447 pp., 13 pis., 23 figs., 

 26 atlas sheets. This is the fifth of the monographs published 

 by the Survey which deal with the geology of the various iron- 

 producing districts of the Lake Superior region. The ore deposits, 

 which make the region of great interest, are strikingly like those 

 of the Marquette district. The ore bodies are usually found 

 either at the bottom of a highly folded chert or jasper formation 

 and resting upon an underlying igneous mass folded into a syn- 

 clinal trough, or within the iron-bearing formation and resting 

 upon intercalated silts or intruded dikes of igneous rock. The 

 mode of origin assigned to the ore bodies is the same in general 

 as that given for the other districts, and which has been described 

 in detail by Van Hise in the monograph on the Penokee district. 



The monograph is well illustrated and is accompanied by an 

 atlas giving detailed maps of the area. A useful feature is the 

 introductory outline, which gives a brief summary of the matter 

 treated in the book. w. e. f. 



Bulletin No, 211. Stratigraphy and Paleontology of the 

 Upper Carboniferous Rocks of the Kansas Section, by George I. 

 Adams, George H. Girty and David White. 123 pp., 1903. 

 The area covered is situated in Eastern Kansas, and represents 



