412 



SCIENCE. 



[N. S. Vol. IX. No. 220. 



ing the last score of years, as will appear from 

 an outline of the chief topics. Thus we have 

 young rivers, with lakes, falls and rapids as 

 marks of immaturity ; graded rivers and the 

 development of valleys ; meanders and the 

 shifting of divides ; mature and old rivers ; re- 

 vived, antecedent, engrafted and dismembered 

 rivers, the causal or historical notion appearing 

 at every stage of the discussion. 



The general reader who desires to cultivate 

 an appreciation for natural scenery will find 

 help in Professor Davis's volume, and the stu- 

 dent to whom most of the materials are familiar 

 will find a convenient and systematic summary 

 of the important facts and doctrines of a great 

 and growing science. 



Albert Perry Brigham. 



Colgate University, February, 1899. 



GENERAL. 



The Bulletin of the American Mathematical So- 

 ciety states that advices from the Vatican an- 

 nounce that Abbe Cozza Luzzi, assistant libra- 

 rian, has found Galileo's original manuscript 

 treatise on the tides. The manuscript is in 

 Galileo's handwriting and concludes with the 

 words : ' Written in Rome in the Medici Gar- 

 dens on January 8, 1616.' The currently ac- 

 cepted text, the original of which was supposed 

 to have been lost, differs considerably from that 

 of the manuscript just found. Pope Leo XIII. 

 has taken the greatest interest in the discovery 

 and has ordered the manuscript to be published 

 in an elegant edition at the expense of the 

 Vatican. 



The London Times announces that it will pre- 

 pare a supplementary volume to the ninth edi- 

 tion of the Encyclopaedia Britannica. This edi- 

 tion was published between 1875 and 1889. It 

 is well known that the treatment of scientific 

 subjects are in many cases the best accessible to 

 English students, being prepared by leading 

 English men of science. It is unfortunate that 

 a new edition of the Encyclopsedia cannot be 

 prepared, as the last twenty-five years have 

 brought many changes in all the sciences, but a 

 supplementary volume will be of some service. 



BOOKS RECEIVED. 



A Handbook of Medical Climatology. S. Edwin Solly. 

 Philadelphia and New York. 1897. Pp. xii + 470. 



ilinerals in Rock Sections. Lea McIlvaine Luquer. 

 New York, D. Van Nostrand Co. Pp. vii + 117. 



Die Medial- Fernrohre. L. Schupmann. Leipzig, 

 Tuebner. 1899. Pp. iv + 145. Mark 4.80. 



Die Lehre vom Organismua und ihre Beziehung zur 

 Sozialwissenschaft. OscAR Hertwig. Jena, Fisclier. 

 1899. Pp. 36. Mark 1. 



Eegeneration und Enlwicklung. H. SxRASSEE. Jena, 

 Fischer. 1899. Pp. 29. Mark 1. 



Elementary Physiology. BENJAMIN MOOEE. New 

 York, London and Bombay, Longmans, Green & 

 Co. 1899. Pp. it + 295. 



Primer of Geometry. James Sutherland. London, 

 New York and Bombay. 1898. Pp. 117. 



SOCIETIES AND ACADEMIES. 



THE geological CLUB OB^ THE UNIVERSITY OF 

 MINNESOTA. 



At a meeting of the Club on February 25th 

 Professor C. W. Hall discussed the extent and 

 distribution of the Archean in Minnesota. 

 First, accepting the Archean as that original 

 ' crust,' or solidified portion of the earth, which 

 is postulated in every existing view of the be- 

 ginning of the geological record, he defined it 

 as an era of igneous origins whose rocks repre- 

 sent the original crystallization of earth matter 

 added to from below by successive solidifica- 

 tion and many subsequent intrusions. By 

 this definition all overlying elastics or irrup- 

 tions into or through the elastics are excluded 

 from the Archean. If the base of the elastics 

 can be found there certainly should be found, 

 locally, at least, the rocks upon which they lie. 

 Such underlying rocks, the Archean, are be- 

 lieved to occur in Minnesota in two quite sep- 

 arated districts, the northern and the south- 

 western. 



Along the international boundary most geol- 

 ogists have grouped all the rocks from Bass- 

 wood Lake to Lake of the Woods as Archean, 

 even when elastics have been clearly recognized 

 and eruptives found breaking through them. 

 Lack of care in delimiting the Archean up- 

 wards has caused much confusion. Lawson 

 set an example in distinguishing between elas- 

 tics, ' agglomerate schists ' and the rocks under- 

 lying, though not necessarily those from which 

 the elastics are derived. Structurally the 



