THE PRIBILOF ISLANDS. 93 



From the nature of the ground covered by the Census of seal 



life impossible. 



breeding seals it is impossible to reach even an 

 approximate estimate of the number of seals on 

 these islands.^ The roughness and unevenness 

 of the breeding grounds preclude the possibility 

 of calculating the number in a given area, so as 

 to obtain a rule which can be applied to other 

 rookeries or to other portions of the same rookery 

 in estimating the seal population. The density 

 of seal life varies according to the size and fre- 

 quency of the rock masses and what might be a 

 correct rule for one locality would be entirely 

 incorrect for another. Besides this, the seals are 

 constantly in motion, the females continually 

 going to and coming from the water and new 

 occupants of the breeding grounds are inces- 

 santly arriving.^ Under these circumstances it 

 is clearly evident that all estimates which attempt 

 to fix the actual number of seals are so unreliable 

 as to be worthy of no consideration for present 

 or future calculations.^ 



On the other hand, any considerable increase Determination 



-, • ,1 1 ji • 1 1 , of increase or de- 



or decrease in the seals on the islands can at crease of seuis. 



1 W. B. Taylor, Vol. II, p. 176; J. li. Moulton, Vol. II p. 71; E. • 

 F. Scribner, Vol. II, p. 89; H. A. Gliililen, Vol. II, p. 110; H. H. 

 Mclntyre, Vol. II, p. 48; H. N. Claris:, Vol. II, p. 159; Daniel 

 Vv^ebster, Vol. II, p. 181. 



- W. B. Taylor, Vol. II, p. 176; H. A. Gliddeu, Vol. II, p. 110; 

 Daniel Webster, Vol. II, p. 181. 



■■■■W. B. Taylor, Vol. II, p. 176; J. H. Moultou, Vol. II, p. 71; 

 B. F. Scribuer, Vol. II, p. 89; H. A. Glidden, Vol, II, p. 110. 



