May 12, 1898] 



NATURE 



29 



may simply indicate that the joke has been worn thread- 

 bare, and not imply any degree of greater respect to the 

 meteorological authority. Increased confidence can only 

 come with greater knowledge, and therefore we are 

 inclined to welcome the demand for a new edition of 

 Prof van Bebber's book as an indication that more 

 attention is being paid to a subject, at least abroad, 

 which nearly concerns the comfort of the community and 

 the prosperity of many trades and callings. 



Moreover, it is distinctly reassuring to find that the 

 methods of weather prediction are in a measure stereo- 

 typed. That no particular change or improvement has 

 been made in these methods, in the space of time cover- 

 ing the issue of the two editions, is a clear indication 

 that they are based on well-ascertained scientific lines, 

 from which the elements of chance have been eliminated. 

 The two sections of the work into which the greatest 

 amount of alteration has been introduced is, first, that 

 dealing with the probable character of the weather over 

 longer periods than twenty-four hours in advance, and in 

 a lesser degree the movements of areas of low barometric 

 pressure. The discussion of the paths along which 

 cyclonic movements preferably travel, has been an 

 inquiry on which Prof, van Bebber has long worked, 

 and though the information derived from the examin- 

 ation of a greater number of instances might be expected 

 to modify the conclusions derived entirely from ex- 

 perience, no great alteration seems to be necessary, and 

 no fresh results appear to be indicated. The percentages 

 of successful forecast or repetition of the same character 

 of weather before, during, and after the passage of a 

 cyclone, shown in the tabular statement, are those 

 derived from a fourteen years' study of the behaviour 

 of these systems. Seven years' further study has ap- 

 parently only confirmed the conclusions originally 

 drawn. 



Only in the section on the possibihty of predicting the 

 weather some days in advance, do we meet with weather 

 charts of a tolerably recent date, an evidence of the 

 author's work during the last few years. Taking it for 

 granted, as we may, that the weather of any region is 

 mainly determined by the barometric pressure and the 

 interchange of areas of high and low barometer, Van 

 Bebber defines five conditions of weather type, deter- 

 mined by the relative positions of atmospheric pressure 

 over the continent of Europe, which conditions are re- 

 peated in their general features with great frequency, and 

 can be easily recognised. The length of continuance of 

 the same weather after the establishment of one or other 

 of these typical systems will vary at different times of 

 the year, and according to the relative positions of high 

 and low pressure ; but, on the average, one can reckon 

 upon the weather remaining unchanged for about three 

 and a half days, and in favourable conditions on even 

 greater permanency. What is now wanted is the means 

 to predict with certainty the transference of one deter- 

 mining type of weather to another. When this know- 

 ledge exists, and the author looks forward hopefully to 

 a time when it will be within our reach, we shall be able 

 to make those longer forecasts which are demanded by 

 the necessities of practical life. 

 NO. 1489, VOL. 58] 



OUR BOOK SHELF. 

 Maryland Geological Surz'ey. Vol. I. Pp. 539, (Balti- 

 more : The Johns Hopkins Press, 1897.) 

 Iowa Geological Surrey. Vol. VI. Report on Lead^ 

 Zinc, Artesian Wells, Sr'c. (Des Moines : Iowa 

 Geological Survey, 1897.) 

 The first volume of the " Maryland Geological Survey" 

 is one of which Prof W. B. Clark, the State Geologist, 

 and others who have been concerned in its production, 

 should be proud. The volume consists primarily of a 

 summary of past and present knowledge concerning the 

 physical features of Maryland, and embraces an account 

 of the geology, pliysiography and natural resources of the 

 State, with a bibliography of all publications relating to 

 these matters. Of exceptional interest is an admirable 

 report by Dr. L. .\. Bauer upon magnetic surveys in 

 general and the magnetic conditions of Marj'land in 

 particular. This report is an inspiring statement of the 

 development and purposes of magnetic surveys, and the 

 valuable information which Dr. Bauer has obtained 

 should induce other States to institute similar inquiries 

 to those carried out by him. The results of such work 

 are not only of great importance to the county surveyors 

 and others who are engaged in determining the 

 boundaries of lands, but are also of wider value on 

 account of the relations which exist between geology and 

 terrestrial magnetism, many magnetic features of a 

 district being related to the geological structure of the 

 underlying rocks. Several fine plates, and other figures, 

 illustrate the report. 



A number of separate papers of general economic 

 interest are included in the sixth volume published by 

 the Iowa Geological Survey, under the direction of Dr. 

 S. Calvin, the State Geologist. Prof A. G. Leonard 

 describes the lead and zinc deposits of the State, and 

 Dr. S. W. Beyer the Sioux quartzite and certain associated 

 rocks. Prof W. H. Norton gives a detailed account of 

 the artesian wells of Iowa, which should be found of 

 considerable value by the citizens of the State ; and Mr. 

 H. F. Bain describes the relations of the Wisconsin and 

 Kansan drifts in Central Iowa. The volume thus con- 

 stitutes a worthy contribution to the economic geology 

 of Iowa. 



Elementary Chemistry, Practical and Theoretical. First 

 Year's Course. By T. A. Cheetham, F.C.S. Pp. 128. 

 (London : Blackie and Son, Ltd., 1898.) 

 This is an addition to the class of school books contain- 

 ing experiments which aim at developing a pupil's think- 

 ing powers rather than at supplying " useful knowledge " 

 of the kind contained in elementary books of science a 

 few years ago. It is an exercise book constructed on 

 sound principles by a teacher of experience ; therefore 

 the experiments have an educational value, and are also 

 practicable. The pupil is instructed to " observe what 

 happens when mercury is heated," " observe the effects 

 of heating sulphur under different conditions," " heat a 

 weighed quantity of chalk, and find whether there is a 

 gain or loss of weight," and so on, instructions being 

 given how to proceed in each case. The course of work 

 and study follows closely that proposed in the British 

 Association Report on the Teaching of Chemistry, and 

 the scope of the treatment includes the laws of chemical 

 combination. The first part of the book is devoted to 

 practical work, while the second contains material for 

 lecture experiments and theoretical information to be 

 studied in connection with the practical work of the 

 laboratory. 



The plan and execution have much to commend them, 

 and the volume is a distinct advance upon the text-books 

 of the days before the new methods of teaching chemistry 

 had been developed. No book of science should, how- 

 ever, be published without an index. 



