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SCIENCE 



[N. S. Vol. XXXIV. No. 864 



Minnesota Algw. I. The Myxophyceffi of North 

 America and Adjacent Eegions, Including 

 Central America, Greenland, Bermuda, the 

 West Indies and Hawaii. By Josephine 

 TiLDEN. Pp. iv + 328, pi. 1-20. 1910. 

 This book, with the modest title of "Min- 

 nesota Algas," treats of the blue-green algae of 

 North America and adjacent regions. It ap- 

 pears as a Eeport of the Survey, Botanical 

 Series, No. 8. As the author states in the 

 preface, it is largely compiled from numerous 

 publications, though she has also drawn on 

 her long experience in the study of the algse. 

 It has been published chiefly for the purpose 

 of encouraging students in the collection and 

 study of this group of algse about which so 

 little is at present known in this country, and 

 to provide students, who do not have access to 

 the numerous publications, with descriptions 

 of all the species thus far accredited to the 

 region. Illustrations of many of the species 

 are also presented which should aid in the 

 determination. These illustrations are largely 

 copied (by means of photographs and tracings) 

 from the classic monographs by Bornet & 

 Plahault, Gomont, etc., though some of them 

 are original. The illustrations, therefore, in 

 general should be valuable for their accuracy, 

 though they have suffered somewhat from an 

 artistic point of view. 



The descriptions are said to follow, in gen- 

 eral, those of Gomont, Bornet, Thuret and 

 riahault. Keys to the genera and species will 

 assist the student in the recognition of the 

 species. 



Four paragraphs are usually given to one 

 species. The first one gives the name of the 

 plant with a few references to works where it 

 is described. The second paragraph is usually 

 a long one giving references to articles (with 

 full title of the article) or works in which the 

 plant in question figures in a list or descrip- 

 tion. Some synonymy is also mixed in with 

 this bibliography of the species. As the au- 

 thor suggests, there is a certain convenience 

 in having these references under each species, 

 but they thus occupy a large part of the book 

 because of repetition, and the example could 

 probably not be followed in many cases except 



where funds for publication are freely avail- 

 able. The third paragraph gives a description 

 of the species, while the fourth one gives the 

 distribution by states or countries, including 

 the particular local habitat, which in some in- 

 stances is quite definitely indicated. 



Since the use of double plates renders it im- 

 possible to have descriptions of figures on a 

 page facing the plate, references to the fig- 

 ures would have been rendered much easier if 

 names and corresponding figure numbers had 

 been printed at the bottom of each plate. 



It is to be inferred from the Introduction 

 that the author contemplates another volume 

 on the same group of algse sometime in the 

 future which is to be of a monographic na- 

 ture. If the present work succeeds in interesting 

 a sufficiently large number of persons in differ- 

 ent parts of the country who have the time 

 to collect, study and preserve the mate- 

 rial in their region, and if the author can 

 make a thorough and critical study of all this 

 material, comparing it with type material or 

 authenticated specimens in the herbaria of 

 Europe, and bring it together with the ac- 

 curacy, judgment and finish shown by some of 

 her European predecessors, it will furnish us 

 with an exceedingly valuable contribution to 

 American algology. Geo. F. Atkinson 



A Study of the Aisorption Spectra of Certain 

 Salts of Potassium, Cohalt, Nickel, Copper, 

 Chromium, Erhium, Praseodymium, Neo- 

 dymium and Uranium as affected hy Chem- 

 ical Agents and hy Temperature. By 

 Harry C. Jones and W. W. Strong. Johns 

 Hopkins University. Pp. 159, 98 plates. 

 Publication No. 130, Carnegie Institution 

 of Washington. 



In this monograph the authors have re- 

 corded the results obtained from the study of 

 about three thousand solutions of salts of 

 potassium, with a colored anion, cobalt, nickel, 

 copper, chromium, erbium, praseodymium, 

 neodymium and uranyl and uranous uranium. 

 " The effect of the addition of free acids and 

 foreign salts on the absorption spectra is 

 studied at some length and in considerable 

 detail and results have been obtained which 



