July 31, 1913'J 



NATURE 



555 



German Imperial Board of Health), which seem 

 to show that the risk of infection from tuberculous 

 milk is surprisingly small. 



Clean milk, and methods of producing and con- 

 trolling it, are dealt with at some length, and some 

 interesting details are given respecting certified 

 milk. 



A long chapter is devoted to pasteurisation of 

 milk, and this process is strongly advocated, under 

 proper safeguards, such as labelling with the time, 

 temperature, and date of pasteurising, as a general 

 method for treating the milk supply if a pure 

 milk cannot otherwise be guaranteed. 



Singularly little is said respecting infants' milk 

 dep6ts. In view of the comparison made by 

 some between the United States and this country 

 in this respect, we should have expected more 

 information had this method of dealing with infant 

 mortality the importance which some would 

 ascribe to it. Altogether the book is a valuable 

 one, and one to read, ponder, and digest. 



R. T. Hewlett. 



OUR BOOKSHELF. 



Theoretische Astronomic By Dr. W. Klinker- 

 fues. Neubearbeitung von Dr. H. Buchholz. 

 Dritte verbesserte und vermehrte Ausgabe. 

 Pp. xxxviii+ 1070. (Braunschweig: F. Vieweg 

 und Sohn, 1912.) Price 50 marks. 

 The claims of Klinkerfues and Buchholz are 

 readily admitted by all acquainted with the calcu- 

 lation of orbits. The classical treatises of 

 Oppolzer and Watson having run out of print, 

 it was most fortunate that this, the practical, side 

 of gravitational astronomy was taken up by 

 Buchholz, who extended the original work ofi 

 Klinkerfues to make it fit to take the place of 

 the former works. The plan of dividing the sub- 

 ject-matter into lectures (Vorlesungen) is still 

 continued, although much is unsuitable for verbal 

 exposition. Lecture 14, for example, extends 

 to ninety pages, and gives, besides the genera! 

 theory of the earth's rotation, all the formula? 

 necessary for the reduction of observations. 



The greater part of this edition agrees exactly 

 with the last, but the additions are well worthy 

 of attention. The new preface runs to twenty 

 pages, and gives a historical treatment of recent 

 advances in the theory of orbits. Although 

 Gylden's work in no way enters into the subject 

 treated in the work, Buchholz has described at 

 some length the claims of the great Swedish 

 astronomer. We believe that posterity will give 

 to Gylden the place which is due to one who did 

 much for the cause of dynamical astronomy as 

 applied to real, in contrast with merely ideal, prob- 

 lems. The criticisms of Bauschinger and others 

 have led to Harzer's method not being developed, 

 but the vector method of Willard Gibbs is re- 

 tained. We are glad to see that Leuschner's 

 method has been introduced. The method is 

 NO. 2283, VOL. 91] 



carefully explained, the formula; are collected, and 

 a considerable number of examples are worked 

 out. The necessary new table is given, and 

 Oppolzer's M- and N-tables have been reproduced. 



An appendix gives the known errors in the 

 works of Bauschinger and Oppolzer on the deter- 

 mination of orbits. 



The greatest fault of the book is its bulk. For 

 a work intended to assist in the numerical calcula- 

 tion of orbits it is almost essential that the auxiliary 

 tables should be easily manipulated. This work 

 could with advantage be divided into several 

 volumes. J. Jackson. 



New Contour Map of the Near and Middle East 



(The Land of the Five Seas). (London : G. W. 



Bacon and Co., Ltd.) Price Js. 6d- 

 This wall-map includes the empires of Babylon, 

 Persia, Parthia, Egypt, and Rome. It shows the 

 routes of Alexander the Great, Pompey, and St. 

 Paul, and illustrates classical history from the 

 earliest times. The scheme of ten colours makes 

 it possible to show with impressive clearness the 

 close relation between land configuration and the 

 spread of civilisation. The scale of the map is 

 ninety-five miles to an inch. In the bottom left 

 corner an inset orographical map of Palestine is 

 provided. The size of the map as a whole — 40 by 

 30 in. — will indicate that it is scarcely large enough 

 for use in big classes, but it should prove of service 

 to individual students in the higher forms of 

 secondary schools. 

 The Tarn and the Lake. Thoughts on Life in the 



Italian Renaissance. By C. J. Holmes. Pp. 



xi + 48. (London: Philip Lee Warner, 1913.) 



Price 2S. 6d. net. 

 This essay of Mr. Holmes forms very pleasant 

 reading ; originally designed as an introduction to 

 a few studies of Italian painting and sculpture, it 

 overran its intended bounds and became eventually 

 the present little volume. Entertaining analogies 

 are drawn between certain communities of fish 

 and certain societies of men, and though the 

 appeal is more directly to anglers, all readers who 

 appreciate literary expression will enjoy the essay. 



LETTERS TO THE EDITOR. 



[The Editor does not hold himself responsible for 

 opinions expressed by his correspondents. Neither 

 can he undertake to return, or to correspond with 

 the ivriters of, rejected manuscripts intended for 

 this or any other part of Nature. No notice is 

 taken of anonymous communications. .] 



Pianoforte Touch. 

 The question as to whether what is known as touch 

 is due to any peculiarity, apart from the energy, 

 with which the hammer strikes the strings, and, con- 

 sequently, with which the fingers strike the _ keys, 

 would appear to be determinable by direct experiment. 

 Personally I have always held, probably with the 

 majority of people, that touch is dependent on such 

 peculiarities, but the evidence seems to be decidedly 

 against it. A note was struck one hundred times in 

 succession so as to produce sound of as nearly as 

 possible the same intensity; on half these occasions 

 it was struck in a pressing, or caressing, manner ; 

 in the other cases it was struck sharply ; the different 



