April 29, 1886J 



NA TURE 



619 



These two maps are mainly compiled from Dr. Naumann's 

 reconnaissance surveys. 



(3) Magnetic map by S. Sekino, representing the isogenic, 

 isoclinic, and isodynamic lines of Japan, constructed from about 

 200 magnetic observations made at as many different stations. 



(4) Map of the great historical earthquakes, volcanoes, solfa- 

 taras, and hot springs of Japan, by Dr. Naumann and two of 

 his assistants. The relative frequency of earthquakes in different 

 parts of the country is indicated by different shades of brown. 

 The limits of the areas of disturbance of some of the most 

 remarkable earthquakes are likewise given. 



B. Maps Printed ami PublisIicJ. 



(5) Reconnaissance map. Division I., containing the northern 

 part of the main island, from the original survey of Dr. Nau- 

 mann and his assistants (Tokio, 1884). As already mentioned, 

 this map is on the scale of i ; 400,000. The mountains are 

 represented by curves of equal height, 40 metres apart. The 

 map is printed in three colours — the mountains brown, the 

 water blue, w-hile the skeleton and writing are black. The sur- 

 face shape is clearly shown, and the system of representing the 

 mountains is peculiar, and novel at least in a map of such small 

 scale. The curves of equal height are directly used for the 

 production of shades, which latter indicate the amount of slope. 

 Great difficulty was encountered in reproducing this map. There 

 can be no doubt that 40-metre curves applied to a 400,000 scale 

 map represent the utmost limit attainable at present. In the 

 case of an inclination of 45°, which occurs here and there, 

 though rarely, the curves approach each other so closely that a 

 zone of I mm. in breadth contains no less than ten lines ! 

 There are two different editions of the reconnaissance map — one 

 with Roman, the other with Japanese, lettering. On other 

 grounds all these maps are of interest, for they are the first 

 artistic reproduction of the results of a regular topographical 

 .Survey in the far east of Asia. 



(6) The three first sheets of the special Survey, showing the 

 topography of the section Yokohama, Idsu, and Kadzusa. 

 Here also these are two editions. Scale i : 200,000, and the 

 mountains are show n by curves of equal height 40 metres apart. 



(7) Index-sheet, containing the divisions of the whole country 

 into five sections for purposes of the publicition of the recon- 

 naissance map, and into ninety sections for the special map. A 

 short statement gives the progress of the Survey n\i to 18S4, 

 while the various signs employed in the maps are explained. 



Besides the maps here specified, numerous designs, geological 

 sections, landscape representations, tables, &-c. , have been 

 made. A large number of practical reports were made for the 

 Government, some of which have been published, but only in 

 Japanese, and they are therefore inaccessible to the rest of the 

 world. Among the papers thus furnished by the Director him- 

 self were reports on the waste of ores in Japan, on slate deposits 

 and their utilisation, on Japanese building-stones, on the moving 

 sand-dunes on the coast of .Satsuma and how to fix them, on 

 Japanese mineral springs, on the occurrence of gold and copper 

 in various localities, and others. 



As to the scientific results obtained by the Survey, they are of 

 much general interest, but it is impossible in the space at our 

 dis]iosnl to do more than refer to them cursorily. Those 

 specially interested in the geological work may consult Dr. 

 Naumann's book on the subject, " Kau und Entstehung der 

 japanischen Insein " (Berlin, Frredlander Sohn, 1885). Almost 

 .all systems have a ])art in building up the colossal mountain- 

 range forming the Japanese islands. The occurrence of De- 

 \onian. Carboniferous, Triassic, Jurassic, Cretaceous, and 

 Tertiary, was established by well-characterised fossils. A re- 

 markable discovery of Upper Cretaceous Ammonites was made 

 in the Island of Yezo, which Dr. Naumann proves are identical 

 with Indian species of corresponding age. The considerable 

 collection of Tertiary plants is now being studied by Prof. 

 Nathorst, and his researches promise some interesting results, as 

 appears from some preliminary notes already published by 

 him. A monograph on Jurassic plants by Mr. Yokoyama, one 

 of Dr. Naumann's assistants, will shortly appear. In early 

 Tertiary times the Japanese islands contained numbers of 

 elephants, identical with the celebrated species belonging to the 

 old Indian Siwalik fauna (Dr. Naumann, " On Japanese Fossil 

 Elephants," " Palaontographica," xxviii. i). Triassic strata 

 have yielded important fossils corresponding to the well-known 

 Aloiwtis saliuaria of the Alps. Another important result of the 

 Survey is the discovery of Radiolarian slates in almost ev..-ry 

 part of the archipelago. These are of great age, being probably 



older than the Carboniferous limestone, and they are nothing 

 else than hardened mud of the deepest parts of the ocean bottom. 

 Radiolarian mud occurs at present in depths of from 4200 to 

 8400 metres in the western and central parts of the Pacific 

 Ocean, as ascertained by the Challenger Expedition. The mud, 

 as well as the slates, is in great part made up of the micro- 

 scopical skeletons of Radiolarians, and we learn that at remote 

 periods the conditions at the greatest depths of the ocean have 

 been nearly the same as at present, and that in Palfeozoic times 

 a great part at lea-t of the Japanese chain was deeply submerged 

 beneath the sea. Great scientific value must also be attributed 

 to the results respecting tectonic geology, which are perhaps 

 the most prominent of all. The Japanese island chain is one of 

 the finest ex.amples of a mountain-range of unilateral structure ; 

 and there cannot be the slightest doubt that it has been shifted 

 by forces acting from the side of the lapan Sea towards the side 

 of the free ocean. Almost all the eruptive and volcanic rocks 

 are confined to a zone facing the Sea of Japan, while the outer 

 zone is for the greater part made up of folded larger masses of 

 Palaeozoic and prePalxozoic times. Very striking, too, is the 

 great transverse depression, introduced by Dr. Naumann into 

 scientific nomenclature by the name of Fossa Magna, which 

 crosses the main island not far from the capital. It appears that 

 this depression is a kind of fissure or cleft produced by another 

 chain of mountains running from Vries Island to the Bonin 

 Islands. The movements going on in this latter chain may have 

 entered the Japanese chain so as to split it. Some of the largest 

 volcanoes of the country — as for instance the celebrated 

 Fujinoyama — issued from that fissure. An inspection of the 

 geological map shows clearly how the advancing folds were 

 stopped by the Fossa Magna, so that they curve back and go 

 around it. Last, hut not least, the results concerning the mag- 

 netism of the earth may be mentioned. As shown in the 

 magnetic map mentioned above, the magnetic curves are 

 curiously irregular, and these irregularities have an evident 

 connection with those of the geological structure. The Fossa 

 Magna causes the isogonic lines to describe a large irregular 

 curve, like the folds of the geological strata. Dr. Naumann, 

 we believe, is prejiarinj a paper on this subject for the Royal 

 Society, where a fuller treatment of this phenomenon than he 

 has hitherto given may be anticipated. 



It is to be regretted that the Japanese Government does not 

 appear sufficiently aware of the importance of a work such as 

 that carried out by its Geological Survey. Its economical value 

 is probably that which would appeal most strongly to a Govern- 

 ment, and of its utility from this point of view there can be no 

 doubt. The fundamental ideas with which the undertaking 

 started should be revived : the various sections of the Survey 

 must advance with even step, otherwise the work cannot fail to 

 be irregular and dislocated. It may be hoped, too, that the 

 Japanese will know how to utilise the invaluable experience 

 laboriously collected by the Survey during the past five years. 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE 

 Cambribge. — An Examination for Minor Scholarships at 

 Downing College will be held early in June. These Scholar- 

 ships will be awarded for Law, or certain branches of Natural 

 Science. Persons who have not entered at any College in the 

 University are eligible to these Scholarships, which will be of 

 the value of 50/., and tenable until their holders are of standing 

 to compete for a Foundation Scholarship. Further information 

 will be given by the Tutors of the College. 



SCIENTIFIC SERIALS 

 Archives Italieiines tic Biologic, tome vii. , fasc. 1, Rome,. 

 February 1886, contains : — Studies on the drainage of the 

 Roman Campagna, part 5, by C. Tommasi-Crudeli, concludes 

 with the expression of his opinion, based on very numerous 

 facts — (i) that the proposed artificial draining of the Ostian 

 and Maccaresan marshes, and their reclamation, will augment 

 in a great degree the malaria exhalations from these basins : 

 and (2) that the hygrometric condition in which the subsoil of 

 the reclaimed district would exist would render it veiy p'obable 

 that such malaria exhalations would be persistent. He believes 

 that malaria is produced on the earth, and not on the water, 

 and when an area is covered with a sheet of water, and while it 



