NA TURE 



[July i, lycQ 



ALTITUDE TABLES FOR NAVIGATORS. 



Altitude Tables, computed for Intervals of Four 

 Minutes betvjeen the Parallels of Latitude 24° and 

 60°, and Parallels of Declination 24° and 60°, de- 

 signed for the Determination of the Position Line 

 at all Hour Angles ivithout Logarithmic Com- 

 putation. By Frederic Ball. Pp. xxxvii + 313. 

 (London : J. D. Potter, 1909.) Price 156-. net. 



' I ■'HERE are many circumstances connected with 



-»- actual navigation which tend to make calcula- 

 tion on board ship difficult to the inexpert, and we 

 naturally welcome any effort intended to shorten an 

 onerous task and to introduce greater simplicity. The 

 substitution of tables which give an approximate solu- 

 tion of a spherical triangle, involving only a very easy 

 interpolation, is the form that assistance usually takes, 

 and the main feature in the book before us is to make 

 tables, already published, available for wider limits of 

 latitude and declination. As tables extend, and con- 

 trive, perhaps, to serve more than one purpose, com- 

 plications are likely to arise, and however great an 

 ingenuity is displayed in adapting trigonometrical for- 

 mulae to tabular arrangement, if simplicity is sacrificed 

 to ingenuity, the ultimate gain is questionable. 



Accuracy is as necessary as brevity of calculation, 

 and it is possible to be so enamoured with the apparent 

 advantages of tables that the chances of misusing 

 them are overlooked. We have a slight fear that the 

 author has not sufficiently considered this point. It 

 is a mistake to cumber the work with many rules, 

 which put too great a strain on the memory. For 

 instance, the rules for determining the " name " of 

 the azimuth; using different methods within ten 

 degrees of the meridian or of the prime vertical ; inter- 

 changing latitude for declination under certain condi- 

 tions; all these things are apt to be a little burden- 

 some in a moment of stress or excitement. Further 

 than this, there must come a time when tables do not 

 shorten the work, for the number of interpolations 

 becomes excessive. Tables of double entry are always 

 inconvenient to the computer, and when, as in nautical 

 problems, we get three arguments, latitude, declina- 

 tion, and hour angle, for other values than those in 

 the tables, the process becomes very laborious. In an 

 example given, it is necessary to take out four altitudes 

 with arguments of even degrees of latitude, and of 

 declination, and to make three interpolations between 

 these altitudes. Not a word is said about the signs 

 of the corrections, and it is quite possible to use an 

 incorrect sign. In any case, the attention is kept on 

 the strain more than if a direct calculation of altitude 

 ■was made from the ordinary trigonometrical formula. 



We may ask, too, whether the use of logs, for 

 solving the simplest question in rule of three is not 

 a little overdone. We have a problem, in which is 

 given the difference of altitude for 60', and it is 

 required to find the proportional amount for 4i'6'. 

 The correction Is worked out by logs, involving three 

 entries. 



But these are little technical points, on which, no 

 doubt, the author's information is a safe guide. He 

 has actual experience to lead him aright, and we are 

 NO. 2070, VOL. 81] 



prepared to surrender our opinion to his practical 

 judgment. On a more important point we are entirely 

 with Mr. Ball. We recognise that this is part of an 

 effort to impress, especially, on the Mercantile Marine, 

 the necessity and the advantage of employing modern 

 methods of tried excellence, and the desirability of 

 abandoning obsolete processes. In these days of rapid 

 locomotion at sea, it is more than ever necessary to 

 produce a correct result in the shortest possible time, 

 and when the expenses of ship management are so 

 enormous, it is a matter of prime importance to know 

 the exact position of the vessel, and to ensure accurate 

 landfall. No time must be lost in groping about to 

 pick up a light, no hesitation must be allowed in deter- 

 mining the ship's course and speed. We trust the 

 author will be successful in enforcing the lesson he ha^ 

 at heart. 



OUR BOOK SHELF. 



Guide to the Whales, Porpoises, ami Dolphins (Order 

 Cetacea), cxliihited in the Department of Zoology. 

 British Museum (Natural History), Cromwell Road, 

 London, S.W. Pp. 47. (London : British Museum 

 [N.H.], 1909.) Price 4J. 



The whale-room in the Natural History Museum is 

 one of the most notable and interesting features of the 

 national collection, and the publication of a new guide 

 to its contents calls for a word of comment. Within 

 fifty pages Mr. Lydekker has compressed not only a 

 series of clues to the models, skins, and other pre- 

 parations, but has furnished students of zoology gener- 

 ally with a most useful and well-illustrated summary 

 of the chief characters of the Cetacea and of their 

 presumable ancestors. In a prefatory note. Dr. 

 Harmer gives reason for confining exhibits of this 

 order to skeletons and models, but it is to be hoped 

 that the public will always have an opportunity of see- 

 ing the skins of some of these impressive animals, in 

 order to judge of their proportions. The only feature 

 of this excellent guide that we could have wished more 

 fully expounded, relates to the puzzling vernacular 

 names of whales that are used by fishermen. The 

 members of our own branch of the international sea 

 investigation are often quite at a loss to know what 

 these names correspond to in scientific nomenclature, 

 and their experience is not unique. The matter has 

 some importance since the cetacean fauna of the 

 north-western seas is probably more familiar to fisher- 

 men than to naturalists, and the fisherman's records 

 cannot be stated precisely until we are able to under- 

 stand the vernacular terms in use. 



La Naissaiice de I'Intelligence. By Dr. Georges Bohn. 

 Pp. 350. (Paris : Ernest Flammarion, igog.) Price 

 3.50 francs. 



This book is the latest addition to the well-known 

 series of volumes entitled the " Biblioth^que de Philo- 

 sophic scientifique," and, in both matter and style, 

 easily reaches the high standard of excellence set 

 by its predecessors. The author restricts his atten- 

 tion to the psychology of the lower organisms, and 

 has succeeded in giving an extremely interesting 

 account of a part of modern comparative psvchologv 

 hitherto rendered attractive only at the expense of 

 truth. An implacable foe to the " anthropomorphism '* 

 of the last generation of comparative psychologists, 

 Dr. Bohn devotes a large part of the earlier chapters 

 of his book to a full statement and vigorous defence 

 of Loeb's theory of tropisms, relieving it of several 



