660 GEOGRAPHY 



The map of the world ought to be completed, and it is the duty and, 

 I believe, the interest, of every country to complete at least that por- 

 tion which includes its own territory. An imperial policy which 

 ignores such an imperial responsibility is a thing of words, and not 

 of deeds. Unsurveyed and unmapped territory is a danger, as well 

 as a disgrace, to the country possessing it, and it would hardly be too 

 much to say that boundary disputes would be unknown if new lands 

 were mapped before their mineral wealth is discovered. The degree 

 of detail required in any survey depends upon the importance of the 

 region. The desideratum is not a large-scale map of every uninhabited 

 island, but a map of the whole Earth's surface on the same scale, which 

 for the present may be a small one, and might very well be that of 

 1: 1,000,000 proposed by Professor Penck, and now being carried into 

 effect for the surveyed portions of the land. Such a map ought to 

 include sub-aqueous as well as sub-aerial features, and when com- 

 pleted it would form a solid basis for the full discussion of many pro- 

 blems which at present can only be touched upon in a detached and 

 unsatisfactory manner. The first problem which it would solve is 

 the measurement of the volume of the oceanic waters and of the 

 emergent land, so that the mean depth of the oceans and the mean 

 heights of the continents might be exactly determined. This would 

 involve, besides the horizontal surveys, a vertical survey of consider- 

 able accuracy. At sea the vertical element is easily found, and the 

 depths measured by surveying and exploring vessels in recent years 

 are very accurate. They must, however, be made much more numer- 

 ous. On land, outside the trigonometrically surveyed and spirit- 

 leveled countries, the vertical features are still most unsatisfactorily 

 delineated. Barometric determinations, even when made with 

 mercurial barometers or boiling-point thermometers, are uncertain 

 at the best, while when made with aneroids they afford only the 

 roughest approximations to the truth. Where leveling is impracti- 

 cable, angular measurements of prominent heights, at least, should 

 be insisted on as an absolute necessity in every survey. 



When a map of the whole surface of the Earth on the scale of 

 1:1,000,000 is completed, we may consider the residual problems as 

 solved. This is far from being the case as yet, and in the present 

 circumstances the most useful work that the geographical societies of 

 the world could do would be to secure the completion of explora- 

 tional surveys to that scale. The system of instruction for travelers 

 established by the Royal Geographical Society has equipped a large 

 number of explorers and colonial officials as expert surveyors, and 

 the result is now being felt in every quarter of the globe. This is not 

 the highest geographical work, but merely preliminary and pre- 

 paratory; yet progress is checked, if not barred, until it is accom- 

 plished. The map of one to a million is not to be viewed as an end in 



