500 



NATURE 



[February i6, 191 i 



tion of Lummer's "Photographic Optics." A separate 

 chapter deals with the reflexion and refraction of 

 astigmatic bundles of rays, and in a further chapter 

 the colour aberrations are discussed. 



The last chapter, which is of considerable Import- 

 ance, reproduces Abbe's theory of the action of the 

 "stops" in an optical instrument, and deals generally 

 with questions depending on the aperture and the 

 field of view. 



The preceding notes will sufficiently indicate the 

 scope of the book. It is confined to the discussion 

 of general optical principles, and methods of calcula- 

 tion applicable to optical instruments, and does not 

 actually deal with the application of these methods. 

 It thus covers practically the same ground as 

 vol. i. of " Die Theorie der optischen Instrumente " 

 already referred to. The subtitle of that volume, 

 "Image formation in optical instruments from the 

 standpoint of geometrical optics," is, indeed, excel- 

 lently descriptive of the present work. The range is 

 sufficiently extensive, and it would hardly be possible, 

 within the limits of a single volume, to include in 

 addition the theory of lens design, or the application 

 of the general principles to special types of optical 

 instruments. On the other hand, a volume, or rather 

 volumes, dealing with these applications are urgently 

 needed. It is to be feared that there are many prac- 

 tical opticians in this country to whom it may appear 

 that this work offers little of immediate practical 

 importance, and to whom it would only be possible 

 to work back, so to speak, to the present volume from 

 one dealing with its immediate application to, say, the 

 telescope or the photographic lens. It is earnestly 

 to be hoped that Prof. Southall may be persuaded to 

 provide them with the opportunity. There are few 

 who have his equipment for the task, and the need 

 is universally recognised. There can be no question 

 that by the issue of the present volume Prof. Southall 

 has rendered a great service to American and to 

 English opticians. 



It may be added that the general get-up of the book 

 is excellent; the type is clear, and the figures well 

 drawn. Some of the figures, however, would have 

 been much improved if they had been reproduced on 

 a somewhat larger scale. 



MANCHURIA, KOREA, AND RUSSIAN 

 TURKESTAN. 

 The Face of Manchuria, Korea, and Russian Turke- 

 stan. Written and illustrated by E. G. Kemp. Pp. 

 xv + 248 + xxiv plates. (London: Chatto and 

 Windus, 19 10.) Price 75. 6d. net. 



THE facilities afforded by extended railway com- 

 munication to remote regions of eastern Asia 

 have rendered it possible for the leisured tourist to 

 travel safely, and with comparative comfort, from 

 Russia to the seaboard of Asia on the east in a direct 

 line traversing a vast area, a great part of which still 

 remains unexplored, especially in Korea and Russian 

 Turkestan, although excellent work has been done 

 within the last decade by intrepid travellers in cross- 

 ing the deserts, and surveying the mountain chains 

 in which this part of Asia abounds. Judging from 

 NO. 2155, VOL. 85] 



previous work, the author, as an expert tourist, has 

 had some useful training, and has not wholly confined 

 descriptions of the route to the face of things, but 

 has invested the work with unusual interest by histor- 

 ical and other notes concerning the races inhabiting 

 the countries traversed. Four months covered the 

 outward and return journeys, following the lines of 

 the Transsiberian Railway, and onward by connecting 

 lines to Korea, and home again. 



The result is the volume under review, which forms 

 an attractive addition to tourist literature, a pictur- 

 esque guide-book so agreeably written as to captivate 

 the reader who has neither time nor opportunity to 

 follow in the author's footsteps. The historical notes 

 arc discriminating and sufficient for the purpose, 

 while the accounts of various regions and races in- 

 habiting them, their religion, social condition, &c., 

 are not without interest. The political outlook created 

 by the new alliance of Russia and Japan is 

 painted in sombre colours. The Japanese determined 

 by force, if necessary, to coerce the Chinese into 

 throwing Manchuria open to Japanese colonisation, 

 and the attitude of China to resist advances. On the 

 other hand, there is Russia's demand to construct and 

 control a railway direct from Irkutsk to Peking, and to 

 prevent the Chinese running a line into Mongolia. 



The position created for China is therefore not with- 

 out the gravest peril, and in the future may lead to 

 serious complications in view of China's progress as 

 a military Power. The author acknowledges indebted- 

 ness for trustworthy information supplied along the 

 route. The line into Manchuria joins the Trans- 

 siberian Railway with the continuation of the line to 

 Mukden and Peking, enabling the traveller to reach 

 the Chinese capital, starting from London, in about 

 seventeen days. The Japanese appear to have been 

 forestalled in their desire to colonise Manchuria, as 

 the country is being rapidly overrun by Chinese immi- 

 grants, owing to its great fertility, and affording an 

 excellent home to the settlers, who are more pros- 

 perous than elsewhere in the empire. 



The first section of railway to Kharbin is under 

 Russian control, having soldiers posted at intervals 

 all along the line. Half-way from Kharbin to Mukden 

 it becomes Japanese, having military officers on board 

 the trains. The author's brief historical note on 

 Manchu history may be rendered all the more interest- 

 ing by a perusal of Mr. Meadows's "History of the 

 Manchus." It goes back to the. eleventh century B.C., 

 and is full of adventure, enterprise, and war up to 

 1644, when the Manchus conquered and founded the 

 present dynasty as rulers of China, when they settled 

 down, adopting Chinese methods of government. 



Mukden, the Manchu capital, a picturesque and 

 famous old city, is visited and described. It has 

 fallen into decay, although not without signs of re- 

 newed life by the transforming influence of the West. 

 The old palace museum contains perhaps the finest 

 collection of ancient Chinese bronzes and porcelain 

 that exists. Some account is given of the Boxer 

 rising and ravages. The hospital of the missions was 

 wrecked, but has been rebuilt, and we are pleased to 

 note that the Viceroy has promised to contribute 480Z. 

 annually in support of this beneficent institution. The 



