592 



NA TURE 



[OCTOBEK l8, 1894 



for verj- accurate work. No mention, either, is made of 

 any form of switch-board, such as that designed by Prof 

 S. P. Thompson, for the interchange of the coils when 

 using Carey Foster's method of comparing resistances. 

 A good description, accompanied by several excellent 

 diagrams, is, however, given of Kelvin and \'arley"s 



uniform temperature all the year round, and the slight 

 eccentricity of the earth's orbit would be sufficient to 

 awaken recollections of the succession of the seasons. 

 Life would indeed then be one perpetual spring. 



The idea of decreasing the obliquity of the ecliptic is 

 only an incidental part of Mr. Astor's story. The 



slide, and of Kelvin's apparatus for the comparison of '\ greater part of the book is taken up by an account of a 



low resistances. journey to Jupiter and Saturn. But, before passing to 



The remaining chapters are devoted to the measure- this section, we must point out that a certain looseness 



ment of high resistances, of batteries, and of electrolytes. 

 There are six appendices, in which the mathematical 



of expression is manifest in the previous one. The 

 project of changing the obliquity is constantly referred 



theory of the Wheatstone's Bridge, Lord Kelvin's method 1 to as one of " straightening the terrestrial axis." The 

 of measuring low resistances, and Manse's method of I impression that the general reader will obtain from such 



an expression is that the earth's axis is only "straight'' 

 when it stands bolt upright, as it were, in the plane in 

 which our globe revolves round the sun. How the 

 author came to use the word " straight " in the sense 

 which he does, passes our comprehension. Another and 

 really less important matter, is that the earth's axis is 

 said to be " inclined to the ecliptic about 23! degrees." To 

 be correct, the author should have said that the inclina- 

 tion to the ecliptic is 66),", and that the angle between 

 the axis and a perpendicular to the ecliptic is 23^. 



We come now to the Hying machine. Jules \'erne 

 utilised known powers when he sent his imaginary car 

 from the earth to our dreary satellite. Others who have 

 followed m his wake have had to hypothecate their 

 forces. Apergy is the force employed by Mr. .Vstor's 

 characters. Similarly electrified bodies repel one 

 another, argues he, then why may not matter exist in 

 such a condition that gravitational attraction becomes 

 apergetical repulsion .' Given such a source of perpetual 

 energy under control, and, heigh presto, away we can go 

 inio the realms of space, with concentrated extracts for 

 food, and liquid oxygen for air supply. Three individuals 

 undertook this kind of voyage in the year a.d. 2000 ; at 

 least so the story goes. One is a learned bore who 

 discourses sapiently on all and sundry circumstances of 

 the journey. For instance, the information he luirls at his 

 companions as Jupiter's largest satellite, Ganymede, is 

 passed, is as follows. " This was discovered bv Galileo 

 in 1610. It is three thousand four hundred and eighty 

 miles in diameter, while our moon is but two thousand 

 one hundred and sixty, revolves at a distance of six hun- 

 vivid imagination, and a brilliant descriptive power, are dred and seventy-eight thousand three hundred miles 

 essential faculties in the man who proposes to give the from Jujiiter, completes its revolution in seven days and 

 public a view of the future as seen through his prophetic four hours, and has a specific gravity of I 87.'' 



measuring the resistance of a battery are given, together 

 with discussions on the E.M.F. of contact at the 

 junctions of a metre bridge, on the discharge of a con- 

 denser through a high resistance, and on the electro- 

 static analogue of a Wheatstone's Bridge. 



The work would have been more useful if its scope 

 had been enlarged, and if it had contained a detailed 

 description of some complete set of instruments used 

 in the comparison of standard resistances, such as are 

 used by the British Association Committee on Elec- 

 trical Standards at the Cavendish Laboratory. Never- 

 theless, it is a good book, written by one who is 

 practically engaged in the manufacture and testing of 

 these instruments, and who, not content with rules of 

 thumb, gives the reason for each point involved in the 

 design and construction. 



There is no doubt the book will be found of great 

 use in every laboratory and testing-room, and is, as the 

 advertisers of patents are wont to say, "calculated to 

 fill a long felt want." W. W. 



AN ASTRONOMICAL ROMANCE. 

 A Journey in Other Worlds ; a Romance 0/ the Future. 



By John Jacob Astor. With ten Illustrations. Pp. 476. 



(London : Longmans, Green, and Co., 1894.) 

 OINCE Jules Verne wrote his "Journey from the 

 •^^ Earth to the Moon," many writers have tried their 

 hands at similar productions, but none have excelled their 

 prototype. A good grasp of the principles of science, a 



eye. We do not think the author isblessedwith a bountiful 

 share of these qualifications ; nevertheless, he has been 

 able to bring forth a book in which instruction and 

 entertainment are happily combined. 



Looking forward to the epoch a.d. 2000, the author 

 saw that many things hid come to pass which are un- 

 dreamt of in the phrlosophy of this enlightened century. 

 The incidents of the story are centred round a scheme 

 for changing the obliquity of the ecliptic, and a machine 

 in which trips are taken to Jupiter and Saturn. It is a 

 source of regret to many people, and especially to those 

 who are doomed to linger in an erratic climate like ours, 

 that the earth's axis is not perpendicular to the ecliptic. 

 If such a condition of things existed at the present time, 

 it could truly be said, " Blessed are they that inherit the ' 

 earth." Every latitude would have its own almost I 

 NO. I3OJ, VOL. 50J 



This individual is brimful of knowledge which wells 

 up at every opportunity, and, after a time, becomes very 

 oppressive. His two companions, on the other hand, 

 though assigned acute understandings and good educa- 

 tions by the author, listen in silence to these tiresome 

 lectures on the most elementary facts of astronomy — an 

 incongruity which is a very weak point in the story. 

 Furthermore, the obtrusive dispenser of scientific scraps 

 is much behind hi= time, for his astronomical knowledge 

 does not go beyond that of the present day. If Mr. .\stor 

 were thoroughly conversant with astronomical investiga- 

 tions, he could have made his professor a much more 

 interesting person. As it is, the man pours forth his 

 spirit in and out of season, and is just the sort of 

 individual that the majority of people are anxious to 

 avoid. 



