83 



firms producing microscopes of any repute exist outside the capital. 

 The instruments of the German firms of Zeiss, Leitz, Hartnack, 

 Seibert, and others are also discussed in pretty full detail, but the 

 productions of other makers are practically ignored altogether. 

 For those (and there should be many such) who wish to make them- 

 selves acquainted with the Continental point of view regarding the 

 microscope. Dr. Kaiser's book will be very valuable. — D. J. S. 



Handbuch der Seenkunde. Allgemeine Limnologie. By Dr. 

 F. A. Forel. 8| x 5| in., x + 249 pages, 1 plate, 16 figures 

 in the text. Stuttgart, 1901 : J. Engelhorn. Price 7 marks. 



The methodical study of lakes and the phenomena connected 

 with them, constituting what is known as Limnology, has been 

 actively pursued for the last three decades by an ever-increasing 

 number of workers, both on the Continent and in America, but 

 by none more zealously than Professor F. A. Forel, of the 

 Lausanne University, the founder of this branch of science. Not 

 only do we owe to him the first attempts to grapple in a compre- 

 hensive way with the many problems presented by lakes, but by 

 his exhaustive monograph on Lake Geneva — " Le Leman " — the 

 third volume of which is said to be now in the press, he has made 

 a contribution to our knowledge of natural phenoinena which it 

 would be difficult to value too highly. A book by him, therefore, 

 on " Lakes, and all About Them," as we may be allowed perhaps 

 to paraphrase the title of the work under review, could not fail to 

 be welcomed by the great number of persons interested in lakes, 

 whether from the physical or biological standpoint. Micro- 

 scopists who have been infected with lake fever will, at any rate, 

 be extremely grateful to Professor Forel for bringing together so 

 much information in such a convenient form. And in passing we 

 may say that those who have not yet extended their collecting to 

 lakes — i.e., to lakes in the true sense, such as occur in the Lake 

 District, North Wales, etc. — can form no conception of the fascin- 

 ating character of the study of limnetic life, or of the superb 

 means of recreation which it affords. In short, those who have 

 never paid any attention to lakes have missed one of the things 

 worth living for. 



In his introduction, after explaining the scope of limnology, 

 and defining what is meant by a lake, etc., Professor Forel dis- 



