PRESIDENTIAL ADDRESS. 481 



positions of different, points are laid Sown, and it is eminently desirable that 

 this should always be done in order that the adjustment of various routes which 

 may intersect in partially-known regions may be adjusted in accordance with 

 definite mathematical processes. Some important expeditions on whicli infinite 

 labour and considerable sums have been expended have presented their results, 

 in so far as they relate to the routes which have been followed and the position 

 of points which have been determined, in such a way that it is impossible to 

 say within what precision such positions have been determined, and con- 

 sequently any combination of these results with those of later expeditions has 

 to be carried out empirically, since adequate data are no longer available for 

 the employment of better and more scientific methods. 



This crude and unsatisfactory way of treating observations, which in many 

 cases have been obtained under conditions of the greatest difficulty and even 

 hardship, is largely due to the lack of interest which geographers have shown 

 in this part of their subject. Methods of observation and methods of com- 

 putation are rarely discussed before any of our Geographical Societies or in 

 any of our publications, and it is only by such discussions that the importance 

 of properly working out the available material at a time when the observer 

 can be consulted on points which are doubtful, or where further explanation is 

 desirable, becomes generally appreciated. 



No set of physical or astronomical observations is ever discussed or even 

 presented without the degree of precision or reliability being definitely stated ; 

 yet in geography this sound rule is too often neglected. 



There are several regions where travellers' routes intersect which should 

 provide ample material for the careful reduction and adjustment of the results. 

 I fear, however, that there would be great difficulty in obtaining the original 

 observations which are indispensable in such an investigation, and in the interest 

 of research it is highly desirable that the original documents of all work of 

 importance should be preserved and the place where they may be consulted 

 recorded in the published account. 



There is room in the geographical investigation of sea and land, even within 

 the limits of the British Empire, for the employment of methods of observation 

 and computation of the highest precision as well as of the simpler and mo)-e, 

 approximate kinds, but everyone who presents the results of his work should 

 deem it his first duty to state explicitly the methods which he employed, and 

 the accuracy to which he attained, in such a form that all who make use of 

 tlieni can judge for themselves of the degree of their reliability. 



In such work, while the instruments used are of great importance, too often 

 the briefest description, such as ' a 4-inch theodolite,' is deemed sufficient. If 

 the observer wi.shes his work to be treated seriously as a definite contribution 

 to science we require to know more than this, and a clear account of the 

 essentials of the instrument, a statement of its errors, and of the methods of 

 observation adopted are the least that will suffice. The account of any expedi- 

 tion should treat so fully of the instruments, observations, and computations 

 utilised to determine the positions of places visited that anyone can re-examine 

 the evidence and form his opinion on the value of the results obtained. A mere 

 tabular statement of accepted values, which frequently is all that is provided, 

 is of small value from a scientific point of view. Probably one reason for this 

 state of things is that too little attention is being paid by geographers to their 

 instruments. Theodolites, levels, compasses, clinometers, tacheometers. plane- 

 tables, pantographs, co-ordinatographs, planimeters, and the many other 

 instruments which are used by the surveyor, the cartographer, the computer. 

 liave in no case arrived at a final state of perfection, but it is seldom that we 

 find a critical description of an instrument in our journals. Descriptions there 

 are from time to time, but these are for the most part weak and insufficient. 

 Not only is a technical description required, which treats fully of both tin- 

 optical and mechanical details, but we need an extended series of observations 

 with the instrument whit'h have been made under the ordinary con- 

 ditions of practical work, and these must be mathematically analysed, and the 

 degree of the reliability of the results clearly demonstrated. The description 

 should be equally thorough and complete, including scale drawings showing the 

 con.struction of the instrument as well as photographs of it. Nothing less th.ni 

 this i.i of any use to the scientific cartographer. 



19J5. I t 



