PRESIDENTIAL ADDRESS. 433 



surveyor. One of the most important lines is the great trianguktion which, 

 it is hoped, will some day run across the continent from south to north, 

 from the Cape to Egypt. Owing to the energies of the late Sir David Gill, 

 this important chain of triangles has already got as far as the southern end of 

 Lake Tanganyika; the part to the west of Uganda near Ruwenzori has also been 

 finished, and it now remains to carry the chain through German East Africa and 

 down the Nile Valley. The latter, it is hoped, will by degrees be accomplished 

 by the Soudan and Egyptian Survey Departments, although it may be delayed 

 for some years yet ; and the former, which was to have been undertaken by the 

 Germans, it is to be hoped will after the war be accomplished by British sur- 

 veyors, through — not German East Africa — but newly acquired British territory. 

 Running right through parts of Africa that are but imperfectly mapped in 

 many districts, the stations of this triangulation will be invaluable for the 

 adjustment of any network of triangulation for future surveys in the interior, 

 and, indeed, have already been utilised for the purpose. 



The carefully carried out boundary surveys between various countries of 

 South America will be of the greatest assistance in future exploration and 

 survey in the interior of that continent, wherever they ars available, while the 

 Survey Departments of Canada and the United States are doing excellent work 

 and extending their surveys far into the imperfectly-mapped regions of North 

 America. So, altogether, the surveyor of the future will soon have a good 

 foundation of reliable points to work from. It is important to remember that 

 running a chain of triangles across a country, though important as a framework, 

 does not constitute a map of the country ; and what is wanted , at any rate 

 in the first place, is a series of good topographical maps, based upon triangula- 

 tion, showing the leading features with sufficient accuracy for the purposes of 

 ordinary mapping, so that on scales of 1 : 250,000, or even 1 : 125,000, there is 

 no appreciable error. 



As regards instruments, the Astrolabe a Prisme is being increasingly used 

 for taking equal altitude observations with most excellent results, but at the 

 present time the five-inch transit micrometer theodolite, already referred to, 

 is perhaps all that is required for general work. It has now been thoroughly 

 tested and found most satisfactory. As regards smaller instruments there is 

 the four-inch tangent-micrometer theodolite, and for rapid exploratory survey, 

 where weight is a great consideration, a little three-inch theodolite has been 

 found useful. 



For base-line measurement the invar type should be taken on all serious work, 

 and for filling in the topographical features a good plane-table is doubtless the 

 instrument to use. In mountainous regions and in some other special conditions 

 photographic surveying doubtless has a future before it, and in military opera- 

 tions when the photographs are taken from aircraft it has proved itself invalu- 

 able ; but in ordinary surveying it is, I think, not likely to take the place of 

 well-established methods. The introduction of wireless telegraphy for\ the 

 determination of longitude is likely to increase in usefulness. Good examples 

 of the work done with it have lately been given in the 'Geographical Journal' 

 and elsewhere. 



Time does not permit of my going more fully into this subject, and I must 

 now bring this address to a close. 



The following Papers were then read : — ■ 



1. France: A Regional Interpretation. By Professor H. J. Fleure, 



D.Sc. 



2. Generalisations in Geography, and more especially in Huvian 

 Geography .^ By G. G. Ohisholm. 



3. The Weddell Sea. By Dr. W. S. Bhuce. 



'■ Published in the Scofthh Gcor/rophiral Mcif/azine, vol. xxxii., November 



iai6. 



1916 F P 



