332 MM. Struve and Dollcn on the Correction 



assent unreservedly ami with full conviction. As regards the 

 question new before us, of adjudicating upon the proposal of 

 Gen. Schubert to the Academy, we are thereby led to this 

 conclusion — that, so far as present knowledge goes, we 

 can recognize no advance in the field of geodesy through the 

 application of corrections to latitudes for calculable local distur- 

 bance, and that an unconditional employment of such correc- 

 tions might lead to most erroneous conclusions. We therefore 

 protest most decidedly against the opinion advanced by Gen. 

 Schubert, that the Russo-Scanclinavian arc is inconsistent with 

 the present state of science because the ground in the vicinity 

 of astronomical stations has not been minutely contoured. 



In the next place, Dollen's argument sets forth clearly that 

 the said contouring is of quite subordinate interest in the 

 geodetic problem of determining the mean figure of the earth, 

 and proves that greater frequency of astronomical deter- 

 minations offers much more certain and efficacious means of 

 rendering innocuous the influence of local disturbance of the 

 plumb-line upon the desired result. On the other hand, how- 

 ever, let us not forget that the levellings accomplished in 

 Great Britain around the astronomical points are of great 

 interest, in that they represent fixed and certain standpoints 

 in the course of geological inquiry. In this respect, we 

 concede readily that the investigations into local attraction 

 presented in the English work are to be regarded as marking 

 an epoch. Had Gen. Schubert proposed that similar re- 

 searches should be undertaken in Russia also, for the purpose 

 of enlisting geodesy in the service of geology, in order to 

 collect material for the latter, we should certainly not have 

 refused to assent willingly to the proposition. 



It may here indeed be mentioned that work of this de- 

 scription has been going on in Russia for years, and that 

 under instructions from the Pulkowa observatory and with 

 the special cooperation of its director. Regarding the work 

 thus undertaken or planned in Russia I may perhaps be 

 permitted to offer here a few words. 



For the purpose of geology it is obviously not essential 

 that the inquiry into local attraction should be prosecuted 

 only at arc-stations. That this has been the case in Great 

 Britain is simply due to the fact, that the whole country is 

 there covered by the geodetic network, and that, from the way 

 in which the work has been executed, all points which are pre- 

 cisely determined astronomically, and geodetically connected, 

 have been incorporated into the arc-measure. It might indeed 

 seem strange that these same researches have not been insti- 

 tuted for all, but only for some of the stations of the arc. 



