346 NATURAL SCIENCE. May, 



told, to begin with, that the luminiferous ether radiates or carries forth 

 the forms and conditions of external objects from the objects to the 

 external organ of perception. Thus we are introduced to the ether 

 as mediating between the perceived object and the perceiving subject. 

 It is then assumed that this ether is the absolute substance, and that 

 it is to be regarded as peculiarly of the nature of spirit. Further- 

 more, it has the capacity of "taking on and setting forth in its own 

 bosom what we may designate spirit copies of all material objects." 

 But, as absolute, it must constitute the material objects themselves. 

 To the question how the qualities of the ether can become the 

 foundations of matter, the author replies, By the process of 

 thickening. " How the spirit form is converted into a material form 

 we have no means of showing further than this, that there is a 

 process of incrassation." The ether thus becomes both the object 

 and the medium by which it is revealed to the subject-mind. What, 

 then, is the nature of this subject-mind ? In answer to this question 

 we are told that " there is much, very, very much, to lead us to 

 believe that the operation of mind is neither more nor less than our 

 old friend in a new position — the ether, found as the spirit medium in 

 physics, and always working in and along with matter." Having 

 now got the ether " incrassated " as matter, the ether "in a new 

 position " as mind, and the ether as spirit medium to mediate 

 between itself as "incrassated" and itself "in a new position," we 

 may regard our solution of the problem of the universe with such 

 complacency as it is in us (not being the author thereof) to 

 summon up. 



It is obvious that we cannot, in Natural Science, do more than 

 barely indicate the nature of the author's thesis. One example of the 

 kind of use to which the principles reached are put must suffice. 

 " The ethereal representation of the sun," we are told, " meets the 

 ethereal representation of the earth, and that of the other planets of 

 the solar system, and thereby maintaining the centripetal relation of 

 each to the sun, while their movement given to each centrifugally 

 balances this relation into a definite circumambience." The illumina- 

 tion thrown upon other matters of physics and of psychology is of 

 like nature. 



C. Ll. M. 



Geology of Sweden. 



SVERIGES GeOLOGI ALLMANFATTLIGT FRAMSTALLD MED EN INLEDANDE HlSTORIK 

 OM DEN GEOLOGISKA FORSKNINGEN I SVERIGE JEMTE EN KOR1 UFVERSIGT AF 



de geologiska systemen. By A. G. Nathorst. Svo. Pp. 336, with several 

 hundred illustrations. 1892-94. Stockholm: F. & G. Beijers. Price 8 kronor 

 [9S-] • 

 The mass of geological literature is now so overwhelming, that 

 everyone will be thankful to an author who gives a clear account of 

 the geology of his own country within a reasonable number of pages. 

 But when the writer is also the person best qualified to deal with 

 the subject, and is in the front rank of original observers, our obliga- 

 tion, and our confidence, become still greater. On looking through 

 Professor Nathorst's handsome volume we find that he has done for 

 Sweden what has been done for few other countries. He has written 

 a geology, or we may, perhaps, better describe it as a geological text- 

 book, in which the greater number of pages is devoted to the forma- 

 tions and types of deposit represented in his own land. Formations 

 absent in that country are only mentioned in the introductory sketch 

 (pp. 20-38), and if good material is available the author always figures 



