of Latitudes for Local Attraction. 327 



state of the case. The subject has been investigated from 

 different sides, so that we by this time possess a whole litera- 

 ture upon it. We must notice especially that it has been the 

 occasion of a very thoughtful hypothesis by Airy, according 

 to whom indeed, at a certain distance from them, the deflection 

 corresponding to the apparent effect of these mountains 

 should not be discernible. The matter, however, as we said 

 before, is by no means exhausted, and this chiefly from the 

 want of a greater number of astronomically determined 

 points. For our purpose it will be quite sufficient to mention 

 the following undisputed facts. At Kaliana, the most nor- 

 thern station of the prolonged Indian arc, in lat. 29° 30 / 48", 

 the attraction of the visible mass of the mountains lying 

 to the north causes, according to Archdeacon Pratt's inves- 

 tigations, a deflection of the plumb-line of %l ,f, % ; by so 

 much therefore, if no other disturbance existed, must the 

 actually observed latitude be less than the mean one, as 

 deduced geodetically from far distant stations. Instead of 

 this, in al] statements of the mean figure of the earth as a 

 whole, which may be considered at all admissible with re- 

 spect to the body of existing measurements, we find for the 

 latitude of Kaliana invariably a quite insignificant correction. 

 Thus, in the comparison on pages 764 and 770 of the oft- 

 cited^English work, we find it to be not quite 2"; and the same 

 thing is observable at stations lying farther away. It cannot 

 be doubted, therefore, that there exist here, besides the 

 obvious, calculable, and so to speak visible disturbances, 

 others, invisible and counterbalancing, of nearly equal mag- 

 nitude. Even if one does not believe in any special connexion 

 or natural link between these two kinds of disturbance, but 

 considers their undeniable existence side by side to be en- 

 tirely accidental, still experience is in this case in no way 

 in favour of the said correction of latitudes. We will not 

 indeed say that it gives decisive evidence against it; for just 

 as little as any one, on due consideration, will deny the natural 

 connexion in this case, so are we, for our part, willing to 

 imagine laws of formation and of stratification for these 

 mighty far-stretching mountains so entirely different from 

 those that prevailed at the origin of the immeasurably 

 smaller and, so to say, wave-like inequalities of surface every- 

 where met with, as to disallow any reasoning from one to 

 the other. As to these last, investigations have yet to be 

 made. It has already been made obvious that we are very 

 much in the dark about them. The only data of sufficient 

 if not always equal trustworthiness that to our knowledge we 

 possess are those given in the English work. Section xi. of 



