8] 



Tluse fi_Mire>, tlmii'Ji not nearly >o complete as we mi-lit \\Ni them to lie. 

 nevcrthele-- exceedingly instructive, and illustrate a lar-c nunil fid truth-.. 



In the !i -t pi, ice they show that a ,;-tion of in des .. 



at CM-IT drive as too old for killing, and that to this extent tin- system i> nut a ruthless 

 one, hui a lilu.al supply lor br i ding p.. In some cases tin- animal taken 



10 liitlr h-ss than its neighbour which is left that the amah i;r can scarcely detect the 

 difference, 3O inconspicuous i- the incipient "wig" or growth 01 l>.nr ov, r the 



withers which deteru.mes the rejection. 



In the second place, the falling pen-entases arc a rough measure of the extent to 

 which the successive drives exhaust, or Ml short of exhausting, the availal)!-.- stock. 



In th ; s instance tl:c conclusion i.- inevitahle thai tlic drain u|.on the Island of 

 St. George was this year much more severe than that upon the Island of St. Paul. 



>r. It is untortunatc that no more exact statistics are available as to the 

 proportion of bachelor seals killed to those released. A careful count of the numbers 

 released uas rot made until we arrived upon the islands, and the rough estimates furnished 

 us for some of the earlier driv\ I as a iia-U lor calculation. 



It is clear that, if we may .equine that the time intervening between two successive 

 drives is sufficient to allow of a thorough redistribution of the bachelor herd, and it' the 

 ea>e he not rendered much more complex by a great diversity in habits, or in the date of 

 arrival of the bachelors oi different ai, r ;:>, then we ou^ht to possess in the fulling percentage 

 of " killable" bachelors in the successive drives a means of estimating approximately the 

 total number ol the bachelor herd for each rookery. 



My colic, i-ue. Dr. John McCowao, has furnished me with the following solution of 

 this problem : 



Lit IK be- the ratio of kilicxl to sjmivd in the second drive, and n the like ratio for 

 thu 



r ! tin' rt'i-ipiMCMl i)f 1 . 



n 



tin- total original innnbfi r linn-.- the number contained in the 



d:ive. 



Km- i-xiiuipli-, takini; the killings IVmn North Rookerj- nml Starayn Atil on July 6 

 and l;i, as being perhnps the lie*t (or the least faulty) instance at hand, 



56 



July 6 n = - 

 H 



46 



.. 13 m = - 



46 



54 253 



56 378 



44 



= (n.-arly) 3 



Now, on the 6th July were killed 700, being 56 per cent, of the drive. 



The drive on the 6th July, therefore, contained 1,^50 seals. 



The whole herd on the Oth July, therefore, contained 1,250 x 3 = 3,".".() *, -als. 



And 3,750 -(- ( .)'J!t ^killed on 20th June) =- 4,7-jO, i> thus iriven us as an approxim I 

 number of bachelors for the hauling-grounds of these two rookeries at the beginning of 

 the season. 



Estimating either by the count of cows or by the yield on the killing-ground 

 two rookeries are equivalent to about one-fifteenth of the two islands; and we, therefore, 

 arrive at a total of somewhat over 70,000 as the number of bachelors (of two years old 

 and upwards) frequenting the islands at the bcninnini: -if la>t M,,M)M. 



The subsequent drive on the 24th July from the same rookeries, at which only 

 17 per cent, are said to have been killed, is unfortunately not available as a check on the. 



