June 23, 192 1] 



NATURE 



535 



Within a year after the armistice some thirty 

 nations and States agreed to two series of inter- 

 national air maps, the general and the local. The 

 Geographical Section of the General Staff has under- 

 taken the work of those sheets which fall within the 

 British Empire. In the Geographical Journal for May 

 Lt.-Col. E. F. W. Lees discusses the proposed maps 

 at some length. For the general map it appears that 

 Mercator's projection, despite all its disadvantages, 

 is to be employed, principally because of its use in 

 navigation and the general training of pilots on naval 

 lines. The scale is to be 3 cm. to 1° of longitude at 

 the equator, and the index is to be based on the 

 index of the international million map. An overlap 

 of 1° of latitude and 3° of longitude is to be allowed. 

 As regards colouring and symbols, some departures 

 must necessarily be made from the conventional 

 usages of maps for terrestrial purposes. Experience 

 has shown what features are of value to the airman 

 in locating his position and finding his way. All 

 water is to be blue ; aeronautical information, such 

 as positions of aerodromes, seaplane stations, light- 

 ships, etc., black; roads, deep yellow or burnt sienna; 

 railways red, because of their conspicuousness to air- 

 men ; and woods green. Red is also to be used for 

 buildings. Hill shading for the depiction of relief 

 on the general map was recommended by the Inter- 

 national Convention, but the employment of the layer 

 sj'stem does not lack advocates. The general ground 

 colour is to be pale green for ground covered with 

 vegetation and pale buff for arid ground. Names 

 apart from those applying to aeronautical information 

 will be sparingly used. The local maps are to be on 

 a scale of i : 200,000. For these the International 

 Convention does not suggest the use of Mercator's 

 projection. An innovation that will cause some 

 criticism is the adoption of a new system of co- 

 ordinate reckoning. Latitudes commence with zero 

 at the South Pole and increase to 180° at the North 

 Pole, and longitudes begin with the present 180° as 

 zero or 360° and run eastward round the sphere. 

 This departure from convention seems to carry no 

 merits beyond the elimination of the letters N. and S. 

 in latitudes and E. and W. in longitudes. 



The Report of the Director, United States Coast 

 and Geodetic Survey, for the year ending June 30, 

 1920, is of considerable interest on account of the 

 large number of charts it contains, many of which 

 illustrate the extent of hydrographic survey along 

 important steamer tracks on the coasts of America 

 and its possessions. These maps show how much 

 detailed work is required even in much-frequented 

 channels in order to ensure safe navigation. Special 

 emphasis is laid on the need for wire-drag surveys 

 on the rocky coasts of the Pacific States and Alaska. 

 The Director also makes a plea for the survey of 

 Alaska, and shows in several charts and diagrams 

 how little has already been done. Ninety per cent, 

 of the coastal waters are uncharted ; where surveys 

 have been made a startling number of dangers to 

 navigation has been discovered. It is essential also 

 that the survey control points in Alaska should be 

 linked up with other surveys of the LTnited States or 

 Canada. Operations have been begun with the co- 

 NO. 2695, VOL. 107] 



operation of the Canadian Government for a line of 

 triangulation from Seattle through south-eastern 

 Alaska, the so-called "panhandle," to the Yukon 

 Valley and Bering Strait. The report indicates the 

 progress made in the detailed survey of the Virgin 

 Islands recently acquired from Denmark. 



Mr. a. W. Giles has studied and mapped the eskers 

 in the vicinity of Rochester, New York, in Proc. 

 Rochester Acad. Sci. (vol. v., pp. 161-240). A very 

 useful bibliography of 126 papers is appended. Mr. 

 J. G. Goodchild's Eden Valley papers (Geol. Mag., 

 1875, 3nd Quart. Journ. Geol. Soc, vol. xxxi.) might 

 be included, since he was one of the first authors to 

 urge a sub-Glacial origin for gravel ridges. Mr. V. 

 Tanner's detailed description of the Lapland eskers 

 (Bull. Comm. giol. Finlande, 1915) might also be 

 added as an elaborate modern study of the deposits of 

 continental ice. Mr. Giles systematically reviews ob- 

 jections to the sub-Glacial theory of eskers, and con- 

 cludes firmly in its favour. The knolls on esker- 

 crests and the interruptions in chains are accounted 

 for in several reasonable ways, and it is made more 

 than ever apparent that an unnecessary amount of 

 mv'stery has grown up round the subject since 

 Hummel's explanation was published nearly fifty 

 years ago. Even the nomenclature has become con- 

 fused, and Mr. Giles's sentence, "The Swedish word 

 'os,' plural 'osar,' sometimes written 'as (asar),' 

 has priority," contains, unfortunately, two linguistic 

 errors. 



The history of geological research in the United 

 States has been enriched by Mr. G. P. Merrill's "Con- 

 tributions to a History of American State Geological 

 and Natural History Surveys," a volume of 550 pages, 

 published as Bulletin 109 of the Smithsonian Institu- 

 tion in 1920. Numerous portraits of the pioneers are 

 given, and a great deal of instructive information may 

 be gathered as to the functions of local surveys and 

 their relations to other State Departments. Much of 

 the material was originally collected by the U.S. Geo- 

 logical Survey, which has now permitted publication 

 in this convenient and comprehensive form. The 

 author refers also to Bulletin 565 of that Survey, in 

 which Mr. C. W. Hayes summarised the work of the 

 Surveys of the separate States. 



Recent drainage operations in the Awanui Swamp 

 in North Island, New Zealand, have disclosed the 

 existence of an elaborate drainage system many miles 

 in extent which, there is good reason to think, mav 

 antedate both the Maori and their predecessors, the 

 Moriori. The discovery is described by the Times' 

 New Zealand correspondent in the issue of June 16. 

 The drains are said to be uniformly about 5 ft. in 

 width and 5 ft. in depth, with regularly sloped sides, 

 the bottom being about 3^ ft. wide. They run for 

 many miles across country in parallel lines perfectly 

 straight, with numerous right-angle cross-drains. An 

 indication of their age is afforded by the fact that in 

 places huge trees of slow growth have grown up in 

 the drains after their formatio.i and decayed. The 

 remains of deeply embedded posts with sharpened ends 

 on a mound in one part of the swamp indicated that 



