of Latitudes for Local Attraction. 329 



Through it direct evidence would be gained of the existence 

 of some natural connection, for the possibility of which we 

 contend^ of the visible disturbances with each other or with 

 unseen counteractions. The immediate consequence of this 

 would be, that it would be necessary to decide in each case how 

 far the contouring should be carried ; for this question could no 

 longer be answered as before, The further the better. Should 

 it, however, be contended that the correction B does effect an 

 improvement of the latitude (or, in other words, bring them 

 nearer to the mean ones), we answer that, with the proof of 

 correlation between the causes in operation, the whole affair 

 puts on a different aspect — an assertion which we will examine 

 presently. First, however, to guard against misapprehension 

 of what is most certain, it must be said clearly that at 

 present matters have not advanced nearly so far. Of the 

 three propositions stated above, only the first has claim to 

 general acceptance, and that indeed not since yesterday only ; 

 the other two depend upon so small a number of places that 

 they can certainly not be regarded as established, even for 

 the small area to which these places belong, namely Great 

 Britain. Even were this the case, the area is yet so small in 

 comparison with the surface of the earth, that a glance at the 

 globe is sufficient to show the inapplicability of a conclusion 

 drawn from such a portion to the whole. If, then, any force 

 could be conceded to the evidence furnished by the English 

 work, beyond the immediate range of the facts, it would tend 

 rather to establish conformity of the disturbances in question 

 to a law. But, in truth, nothing of the kind is yet proved ; 

 only the first noteworthy step has been taken on the road which 

 will certainly lead us in time to a knowledge of wider truths 

 in this region — a goal worthy indeed of the highest effort, but 

 one the attainment of which is sufficiently difficult and un- 

 certain without premature conclusions. In any case it is still 

 far distant ; nor till it shall really have been reached should we 

 think of deciding the question as to the admissibility of these 

 proposed corrections to observed latitudes for the purpose 

 of a determination, however important, of the figure of the 

 earth. 



" In connection with what was said above as to the change of 

 view which must follow upon proof of relation between the forces 

 concerned, we would now show more distinctively how in such 

 case a new conception of the figure of the earth will become 

 necessary. In order that not the smallest doubt may remain 

 on this important point, we will now at the close of our 

 remarks recur to the simple illustration by which at starting 

 we sought to show what is especially meant by geodetic 



Phil. Mag. S. 5. Yob 11. No. 69. May 1881. 2 B 



