July 22, 1898.] 



SCIENCE. 



109 



lery in the British Museum, iu the July number 

 of Natural Science (p. 10) : 



''No museum has hitherto solved the diffi- 

 culty of exhibiting the outward form of the 

 various kinds of whales which baffle the taxi- 

 dermist's art on account of the oily nature of 

 their skin. At last, however. Sir William 

 Flower has solved the problem in a most satis- 

 factory manner, and the result is a unique ad- 

 dition to the Department of Zoology in the 

 museum over which he presides. ' ' 



The solution referred to consists in exhibiting 

 papier mache casts of one-half of the exterior 

 of the various cetaceans, colored as in life, and 

 placing the skeletons iu the concavities of the 

 casts. 



Sir William Flower would, I am sure, dis- 

 claim originality for this excellent mode of ex- 

 hibiting cetaceans, as it has been in use in the 

 National Museum for more than fifteen years. 

 In the Report of the Smithsonian Institution 

 for 1882 (p. 125) will be found the following 

 statement : 



"Mr. Joseph Palmer, chief modeller, has 

 been engaged during a large part of the year in 

 mounting the skeleton and cast of a humpback 

 whale, 33 feet in length, which now stands in 

 the south main hall. This is the largest cast of 

 an animal that has yet been made, and is unique 

 in conception. Viewed from the left side, the 

 visitor sees the cast of a whale in the attitude 

 of swimming through the water. Standing on 

 the right, he sees the concavity and inner out- 

 line of the half cast, in which against a suitable 

 background is mounted the articulated skeleton 

 of the animal." 



This interesting specimen is now in the south 

 hall of the Museum, where it has been exhibited 

 since 1882. The idea of showing exterior and 

 skeleton together originated, I believe, with 

 Professor Baird, who took great interest in the 

 specimen referred to, and never failed to point 

 it out to his friends when passing through the 

 Museum. 



The Museum has a large series of painted 

 casts of the smaller cetaceans, some of which 

 were made as early as 1874, and a number of 

 replicas were shown at the Berlin Fisheries Ex- 

 hibition in ISSO and were afterwards taken to 

 London at the time of the Fisheries Exhibition 



in 1883. Some of these, if I remember cor- 

 rectly, were left in the British Museum by Dr. 

 Goode at the close of the latter exposition. 

 Frederick W. True. 



U. S. National Museum, 

 July 11, 1898. 



SCIENTIFIC LITEEATUBE. 

 A Treatise on Magnetism and Electricity. By 



Andrew Gray, LL.D., F.E.S., Professor of 



Physics in the University College of North 



Wales. Macmillan & Co. 1898. 



The first volume of this treatise awakens a 

 strong desire iu us to see the second volume 

 which is promised. The author in his preface 

 states that his eflFort has been to produce not a 

 work on the mathematical theory of electricity 

 merely, but also to describe the fundamental 

 phenomena, and ' ' to show how they fall into 

 their places in the general scheme of electrical 

 action, and to point out the consequences to 

 which they lead." 



There have been many attempts to simplify 

 and amplify Maxwell's great work, and the stu- 

 dent now has various aids to enable him to com- 

 prehend it, which were not accessible twenty 

 years ago. A distinguished professor of phys- 

 ics once pointed out to me two editions of Max- 

 well's book, worn and dilapidated by constant 

 use, and remarked: 'I am proud of them.' That 

 treatise certainly contained strong food. Long 

 grappling with it and night oil burned in study- 

 ing it led to a certain grip of the subject, the 

 evidence of which we see in such books as 

 Professor Gray's. The student now has Poin- 

 caire's treatise ; Helmholtz's lectures on the 

 electrodynamic theory of light, Drude's Physik 

 des Ethers; Oliver Heavyside's work; Pro- 

 fessor J. J. Thomson's Electricity and Mag- 

 netism, Hertz's Modification of Maxwell's 

 fundamental equations, Webster's Electricity 

 and Magnetism, and the work before us. 



A critic should carefully examine the aim of 

 the author and should not take him to task for 

 omissions that were made designedly, and 

 should not endeavor to instruct him in regard 

 to what he should have done, but rather should 

 aim at weighing what has been accomplished. 

 One should, therefore, carefully read Professor 

 Gray's preface, and heed its words in regard to 



