Feb. 29, 1872] 



NATURE 



539 



hotter, drier, and healthier than that of Zanzibar. Here 

 he did not attempt to strike inland, the weather and the 

 hostility of the native tribes being unfavourable, but re- 

 turned along the coast southwards to Pangani, and 

 thence inland to Fuga, the capital "city "of Usambara, 

 in the Highlands of Eastern Africa. In order to 

 gain a complete knowledge of the Zanzibar coast, he also 

 paid a visit to the island and port of Kilwa, situated be- 

 neath the ninth degree of south latitude. Here are the 

 remains of an ancient town of considerable size, with 

 respect to which many legends are current among the 

 natives ; but the gradual sinking of the coast has rendered 

 the ancient site uninhabitable. Although at the present 

 time a miserable and foetid collection of squalid huts, 

 Kilwa was found in i;oo by the Portuguese a town of 

 great prosperity, the capital of Southern Zanzibar, and 

 ruling the coast as far as Mozambique and Sofala ; but 

 the curses of European wars and the slave-trade have 

 desolated the once thriving countr)'. Captain Burton does 

 not think very highly of the so-called "free labour" 

 system, which he terms "the latest and most civilised 

 form of slavery in East and West Africa." 



The most important expedition made by Captain 

 Burton was, however, that undertaken between 1S57 and 

 lS59to Kazehin the Ukimbu district, upwards of 500 miles 

 from the coast, and about 2° south of the southern shore 

 of the great Victoria N'yanza, in company with Captain 

 Speke. But as this journey has already been illus- 

 trated in his own " Lake Regions of Central Africa," and 

 the country has been further described by Colonel Grant 

 and Captain Speke, he does not again enter into details 

 respecting it ; but thus sums up what he considers its 

 geographical results : — " That the Boringo is a lake dis- 

 tinct from the 'Victoria N'yanza 'with a northern effluent 

 the Nyarus, and therefore it is fresh water ; that the 

 N'yanza, Ukara, Ukerewe, Garawa, or Bahari y a Pili, is 

 a long narrow formation, perhaps thirty miles broad, and 

 240 miles in circumference, and possibly drained to the 

 Nile by a navigable channel ; that the N'yanza is a water, 

 possibly a swamp, but evidently distinct from the two 

 mentioned above, flooding the lands to the south, showing 

 no signs of depth, and swelling during the low season of 

 the Nile, and vice versa ; and that the northern and 

 north-western portions of the so-called ' Victoria N'yanza ' 

 must be divided into three independent broads or lakes, 

 one of them marshy, reed-margined, and probably shallow, 

 in order to account for the three effluents within a little 

 more than sixty miles." 



The botanical results of this journey are about to be 

 illustrated by Colonel Grant, in a magnificent volume, 

 to be published by the Linnean Society, which it is un- 

 derstood will be illustrated by 600 plates, the cost of 

 which will be defrayed entirely by the gallant author. 



One chapter is devoted to a sketch of the labours of 

 Captain Burton's old comrade, Captain Speke. Though 

 tribute is here paid to his many excellent qualities, we 

 regret to be again introduced to the details of the 

 estrangement which grew up between the explorers, 

 culminating at the meeting of the British Association 

 at Bath, when the two companions in arms met as 

 strangers, advocates of two rival "Nile-theories," 

 as to the origin of the Father of rivers. 



In the Appendices, Captain Burton gives some useful 



details of the meteorology, commerce, &c., of Zanzibar. 

 A well-executed map helps to illustrate the author's 

 journeys, without a constant reference to which the 

 narrative is by no means clear ; but we cannot commend 

 the style in which the woodcuts interspersed here and 

 there are executed. 



OUR BOOK SHELF 

 Deschanel's Natural Philosophy. By Prof. Everett. Part 

 III., Electricity and Magnetism. (London and Edin- 

 burgh : Blackie and Son.) 

 In the Preface by the translator of the present volume, it 

 is said, with much truth, that "the accurate method of 

 treating electrical subjects, which has been established 

 in this country by Sir W. Thomson and his coadjutors, 

 has not yet been adopted in France ; and some of Fara- 

 day's electromagnetic work appears still to be very im- 

 perfectly appreciated by French writers." Accordingly 

 we find that the translator has added a considerable 

 amount of matter, and more especially two important 

 chapters, one on the electrical potential and lines of 

 electric force, and the other on electrometers, together 

 with an appendix on electrical and magnetic units. Dr. 

 Everett has thus considerably improved a book, which, in 

 its original form, was already a good one. The ordinary 

 branches of the subject are unfolded, the plates are good, 

 and the explanations are full and clear. The portion 

 devoted to magnetism is in this, as apparently in all such 

 general treatises on natural philosophy, considerably the 

 most defective part, and especially in the sections which 

 relate to terrestrial magnetism. The whole of that 

 question is most insufficiently dealt with. The treatment 

 of the secular changes in the magnetic elements is con- 

 fined to twelve lines,where it is said that "declination and 

 dip vary greatly, not only from place to place, but from 

 time to time ; " but from which we should expect that the 

 unlearned reader would be led into the error that intensity 

 is uniform. Then, again, the vast subject of changes 

 in the elements, such as are not secular, is confined to one 

 short paragraph, headed " Magnetic Storms " ! The 

 intrinsic importance of the subject of terrestrial mag- 

 netism, and the great and increasing interest attaching to 

 it, no less than the extreme beauty of many of its in- 

 vestigations and results, entitle it to a much larger notice 

 than the very imperfect one in this volume. The chapter 

 on the Telegraph contains useful matter, and especially a 

 description of an autographic telegraph, an instrument 

 which, while interesting and ingenious, has not often found 

 its way into such treatises. We miss such points as how 

 to find the locality of a fault in a telegraph wire, which we 

 might the more expect to see treated of when we consider 

 the full explanation which is given of Ohm's laws, and 

 when we see such elaborate details as to some telegraphic 

 instruments as are entered into in the chapter in question. 

 The chapters on the heating effects of currents, and on 

 electrolysis, are clear. The question of electromotive force, 

 and of the means of determining it, might have been 

 entered into more fully ; and, generally, from the character 

 of the chapter on the potential, we might have expected 

 to see a little more introduced concerning points ^vhich 

 may be elucidated by the application of the principle of 

 the conservation of energy. James Stuart 



Mediziiiische yahrbjicher, herausgegeben von der k. k. 

 Gesellschaft der Arzte, redigirt von S. Strieker. Jahr- 

 gang 1871. Heft iv. Mit 4 Holzschnitten. (Wien : 

 1871.) 

 This part, which concludes the first volume of Strieker's 

 Jahrbuch, contains : ( i) Researches on the Inorganic Con- 

 stituents of the Blood, by Adolph Jarisch. Jarisch gives 

 the details of an improved method by which blood can be 



