Decembee 20, 1901.] 



SCIENCE. 



967 



with tabular matter and with mathematical dis- 

 cussions. Dr. Hann has very wisely reduced 

 his tabular matter to a minimum, and has de- 

 voted an appendix to the consideration of the 

 more important physical theories which involve 

 mathematical treatment. A few of the shorter 

 and simpler formulae only are included in the 

 general text. By this arrangement the text is 

 unencumbered, and the reading becomes easier 

 and pleasanter. None of the modern text- 

 books of meteorology, of which there are many, 

 attempt to cover the field which Dr. Hann has 

 so successfully covered. Hence no comparison 

 of the new ' Lehrbuch ' with these text-books is 

 desirable, or even possible. 



There is clearly no need to outline the con- 

 tents of such a book as that now before us. 

 Throughout, in the arrangement of the contents, 

 the treatment of each subject, and the selection 

 of the references, the hand of the master is 

 clearly seen. If we were to single out one 

 chapter which is likely to be of the most gen- 

 eral interest to meteorologists at the present 

 time, it would probably be that dealing with the 

 theory of extra- tropical cyclones, a subject in 

 the discussion of which Dr. Hann has taken a 

 very prominent part, he being a strong advocate 

 of the dynamic theory of the origin of these 

 disturbances. In this country, Mr. H. H. 

 Clayton, of Blue Hill Observatory, and Pro- 

 fessor F. H. Bigelow, of the Weather Bureau, 

 have made interesting contributions to this dis- 

 cussion. An excellent summary of the main 

 facts in the case is given, and the position of 

 the author is made clear by the statement (p. 

 586) : " Es soil also hier die Ansicht vertreten 

 werden, dass es zwar atmospharische Storungen 

 und damit Wirbelbildungen mannigfachen Ur- 

 sprunges giebt, dass aber die Hauptursache 

 derselben, namentlich aller grosseren und 

 langlebigeren atmospharischen Wirbel, in den 

 Storungen der grossen atmospharischen Zirkula- 

 tion zu suchen sein diirfte." 



Americans may well take satisfaction in no- 

 ting the frequent references made by Dr. Hann 

 to the work of Mr. H. H. Clayton and of his 

 associates at Blue Hill Observatory, and also to 

 that of the Weather Bureau. For a book of the 

 size of this ' Lehrbuch ' there are comparatively 

 few illustrations in the way of charts and 



weather maps. Since the publication of Bar- 

 tholomew and Herbertson's new 'Atlas of Me- 

 teorology,' however, there is not much need of 

 introducing charts into text-books of meteorol- 

 ogy, especially when the books are of such a 

 grade as the present one. There are four half- 

 tone views of clouds ; one of lightning ; two of 

 hail-stones, and one of a waterspout. This 

 waterspout is the one which occurred off the 

 southern coast of New England on August 19, 

 1896 (see Science, N. S., Vol. IV., 1896, p. 

 718). Isothermal, isanomalous, isobaric, wind 

 and rainfall charts are included. 



It is seldom that a reviewer has so pleasing a 

 task as that involved in writing a notice of 

 Hann' s ' Lehrbuch der Meteorologie. ' The book 

 is a masterpiece. E. DeC. Wakd. 



A Manual of Determinative Bacteriology. By F. /^ 

 D. Chester, Delaware College Agricultural 

 Experiment Station. N. Y., The Macmillan 

 Co. Price, $2.60. 



Systematic bacteriology is the hete noir of the 

 bacteriologist. The amount of confusion which 

 exists in literature regarding the description of 

 species is hardly conceivable. The descriptions 

 are found scattered through an extensive litera- 

 ture ; they are sometimes verbose and extended, 

 and at other times brief and insuflficient. Any- 

 thing which looks toward a simplification of 

 this complex problem will always be received 

 with relief by bacteriologists. 



The work of Professor Chester is a somewhat 

 modest attempt to give a little assistance in this 

 realm of confusion. It does not pretend to be 

 a study of systematic bacteriology, but rather, 

 as the name indicates, of determinative bacteri- 

 ology. The author has endeavored to collect 

 all species of bacteria which have been suffi- 

 ciently described for even moderately satisfac- 

 toiy determination, and to arrange these within 

 the limits of one medium-sized book in such a 

 way that they can easily be found. By the use 

 of artificial analytical keys, based upon simple, 

 but important characters, the bacteria which 

 the author includes in his list have been classi- 

 fied into easily distinguishable groups. 



The amount of labor which has been involved 

 in the collection and tabulation of these numer- 

 ous species, about 800 in all, is very great. 



