164 



♦ KNOWLEDGE ♦ 



[May 1, 1888. 



Gordon was governor. The two men became fast friends ; 

 and when Gordon was appointed Governor-General of the 

 Soudan he promoted Emin as governor of the Equatorial 

 province, which extends from nine degrees to two degrees 

 north of the equator. A clear and indispensable map, 

 which Mr. Eavenstein has engraved for this volume, enables 

 the reader to follow with ease the various journeys described. 

 It is the record of these visits to the dilferent parts of his 

 province that the letters and journals mainly embody, and 

 they supply a vivid and interesting narrative of the incessant 

 and varied work which Emin has carried on in the face of 

 stupendous difficulty, danger, and discouragement. While 

 engaged in raising and drilling troops, substituting native 

 for Egyptian soldiers, promoting trade, encouraging cultiva- 

 tion of coffee, indigo, cotton, and other products, adding 

 large districts to his territory, not by war, but by skilful 

 negotiation, converting a deficit of over 30,000/. into a 

 surplus of 8,000Z., Emin has also found time to make e.^ten- 

 sive observations on the geology and general features of the 

 province, to form large collections of its jjlants and animals, 

 and to gather copious details concerning the manners, 

 customs, and beliefs of its various tribes, notably of the 

 Monbuttus, a cannibal, but, in many respects, advanced race, 

 to whom he devotes a special section (pp. 18(5-213). 

 Despite a good de;vl of inevitable repetition and of sameness 

 in details, the letters and journals deserve to be read with- 

 out skipping, a task the more easy because their translation 

 has been so skilfully done by the wife of Emin's missionary 

 friend. Dr. Feikin, that they read as smoothly as if the 

 originals had been written in English. 



Geology : Chemical, Pliysical, and SlrathjrapJiical. By 

 Joseph Prestwich, Professor of Geology in the University 

 of Oxford. Vol. II. (Clarendon Press.) — This volume 

 completes the important work into which the ripe results 

 of fifty years' study of the science at which the Oxford pro- 

 fessor has laboured con amove are gathered, and it is from 

 cover to cover worthy of his high reputation. We notice 

 that the publishers give prominence in the advertisements 

 of this book to the advocacy of " the non-uniformitarian 

 views of geology " by its distinguished author, but surely 

 lie can be no party to the sounding of this note of challenge, 

 since his attitude is not that of the defiant extremist which 

 that implien. The day is happily past when the scientist is 

 •sunk in the partisan, for the diflerences between contending 

 schools are often found to be rather of terms than of prin- 

 ciples. Because Lyell, after careful sifting of evidence, 

 abandoned the old catastrophism and argued from the 

 ascertained opei ations of existing causes, that th e same causes, 

 allowing for variation of degree, have sufficed to bring about 

 past changes, a host of purblind followers have contended for 

 an unalterable tiniformitarianism. It is against such extreme 

 applications of the doctrine that Professor Pj'estwich contends 

 when he says that " while the laws of chemistry and physics 

 are unchangeable, and as permanent as the material universe 

 itself, the exhibition of the consequences of those laws in 

 their operation on the earth has been, as new conditions 

 and new combinations succe.s.sively arose in the course of its 

 long geological history, one of constant variation in degree 

 and intensity of action." * Perhaps the word " constant " 

 implies more than we are prepared to admit, but, as Pro- 

 fessor Huxley remarked in his anniversary address to the 

 Geological Society in 18C9 on Geological lleform, " there 

 appears to be no sort of necessary theoretical antagonism 

 between Catastrophism and Uniformitarianism. On the 

 contrary, it is very conceivable that catastrophes may be 

 part and parcel of uniformity." And he illustrates bis 

 meaning by the working of a clock, the good time-keeping 



Vol. i. 



p. VI. 



of which means uniformity of action. " But the striking 

 of the clock is essentially a Gitastropbe ; the hammer might 

 be made to blow up a barrel of gunpowder or turn a deluge 

 of water ; and, by proper arrangement, the clock, instead 

 of marking the hours, might strike at all sorts of irregular 

 periods, never twice alike, in the intervals, force, or number 

 of its blows. Nevertheless, all these irregular, and appa- 

 rently lawless, catastrophes would be the result of an abso- 

 lutely uniformitarian action, and we might have two .schools 

 of clock thcori.sts, one studying the hammer, and the other 

 the pendulum." In his first volume Professor Prestwich 

 dealt with the nature and distribution of the materials 

 forming the crust of the earth, and with the several agencies 

 by which, in the remodelling of those materials, the strati- 

 fied have been developed from the unstratified rocks. The 

 present volume treats of the original condition of that crust, 

 of its anatomy, history, and organic contents, and concludes 

 with a discussion of those abstract phy.sical and cosmical 

 problems which relate to the evolution of the globe and of 

 the system to which it belongs. The distinctive feature 

 of the author's treatment of the stratigraphical branch of 

 his subject is in his insistance on the impossibility of any 

 universal scheme of classification, the formations in distant 

 areas being correlated not by identity of species, but by 

 the presence of the same characteristic genera, the large 

 community of which amongst the Invertebrata everywhere 

 is most striking. He remarks that " the great time- 

 divisions are of almost universal application, but the smaller 

 ' breaks in continuity,' which are of frequent occurrence in 

 all areas, are subject to constant differences of extent and 

 value ; consequently, in filling up the details of the several 

 geographical areas, each one is found to have its own local 

 stamp, and possess its own special terms, some knowledge 

 of which is as essential to the geologist as is the language of 

 a country to the traveller, if he would pass through it with 

 profit " (p. 3). As novel and informing commentary on 

 this, we have several tables of classification showing the 

 equivalent strata in various parts of Europe, and in 

 America, Asia, Africa, and Australasia, with brief " lists of 

 the characteristic genera of plants and animals attached for 

 the purpose of showiug the distribution of some of the more 

 important life forms over the globe at the several con- 

 temporaneous epochs." Altogether, the space given to the 

 geology of other countries is a unique and valuable feature 

 of the volume. Convenient summaries of the faunas 

 and floras of each period are supplied, so that a great mass 

 of facts is helpfully grouped for easier gi-a.sp by the student, 

 for whom also an abundance of excellent plates and wood- 

 cuts, together with a geological map of Europe, are provided. 

 In the chapter on the Quaternary or Pleistocene period, to 

 our knowledge of which the author's researches have largely 

 added, some remarks on the place of man in the geological 

 record are included, and it is significant of a turn in the tide 

 to find Professor Prestwich admitting the probability of 

 man's existence in North-Western Europe in the glacial 

 epoch, the duration of which he thinks may not have been 

 longer than from 15,000 to 25,000 years. This is in 

 keeping with the generally shorter estimates of time than 

 are usually demanded by geologists which characterise the 

 volume, and so far jiaves the way for reconciliation betweea 

 geologists and physicists. 



Chamherss Encyclopcedia. Vol. I., A to Beaufort. 

 (W. & R. Chambers. 1888.) — The publishers remind us 

 in their preface that their great work has been before the 

 world in complete form for twenty years. Revision has 

 gone on at frequent intervals, but the time has arrived for 

 an entire recast of the matter, involving the rewriting of a 

 large proportion, so as to bring down the information to 

 date. So far the work has been well and thoroughly done ; 



