222 Reviews — Radioactivity of Canadian Springs. 



synonymies, and in the description of ])aiticn]ar specinieiis. In this 

 respect the revision of the genus is exceptionally thorough. The 

 207 quarto pages are devoted to 47 species (neglecting varieties) of 

 Calamite stems, of which 41 are of Upper, and 6 of Lower 

 Carboniferous age. Nine of these are new names, and the number of 

 species here first recorded from Britain is a remarkable feature of 

 the work. 



Certain names well known and in constant use are changed on 

 what appear to be slight grounds. Thus C. ramostis, Art., becomes 

 C carinatus, Sternb.; while it is proposed to replace C. approximatus, 

 Brongn. {non Schloth.), by the cumbersome term C. Schutzeifonnis, 

 K. & J., forma Waldenlurgensis, K. One cannot help feeling tliat 

 but little is gained while not a little is lost by such modifications, 

 however defensible they may be made by an appeal to the laws of 

 strict priority of nomenclature. 



We also find an omission of even a bare mention of all petrified 

 material of Calamite stems, in which the anatoinical structure is 

 preserved, which strikes us as unfortunate in the case of a work 

 professing to be a monograph of a genus. 



In conclusion, we hope that our authors may soon be able to 

 resume the publication of this valuable systematic work. If in 

 future parts they could give us, in addition to the purely systematic 

 side, a fuller morphological account on a comparative b^sis of tlie 

 members of each genus, our indebtedness to them would be still 

 further increased. 



E. A. K A. 



III. — The Radioactivity of some Canadian Mineral Speings. By 

 J. Satterly and R. T. Elworthy. Canada, Dept. of Mines, 

 Bull. 1^0. 16, 1917. 



rpHE discovery of the radioactivity of mineral waters — in the case, 

 JL for example, of the springs of Bath — confirmed the belief, long- 

 held, that the specific virtues of manj' spring waters were due to 

 some factor other than the dissolved salts they were known to 

 contain. The therapeutic value of radioactive waters lies in the 

 increased activity of all the processes of nutrition and metabolism 

 which they bring about, in the stimulated growth of red blood-cells, 

 and in the elimination of toxins. Radioactive waters (or gases 

 escaping from such waters) have thus a high economic value, and the 

 Canadian Department of Mines has therefore caused to be carried out 

 a systematic examination of a large number of springs in Ontario and 

 Quebec and of a gi'oup of hot springs at Banff, Alberta. The results 

 are contained in this memoir, together with a general account of 

 radioactivity, its measurement, and its medicinal value. 



None of the Canadian springs contain as much radium as those of 

 Bath. The amount found by Sir William Ramsay in the Bath 

 Springs was 138-7 X 10-12 grams per litre, whereas the highest 

 amount found in Canada is 46 in the same units. Two other springs 

 have 25 and 23-5 units respectivelj^ while the others average less than 

 3 units (the value for sea- water is 1 unit). These figures refer to 



