198 Mr. Corbaux on the La'jos of Mortality, 



Wagtail. — The other two species of Wagtail, namely 

 M. alba and M. Boarula, are both indigenous here ; many of 

 the former, and a few of the latter, remaining the whole year. 



Dr. Heysham in his Catalogue of Cumberland Animals, 

 published in the year 1796, states that both these species en- 

 tirely left this county in the winter ; although he appears to 

 have had some doubts with respect to M. Boarula, from the fol- 

 lowing observation : " Appears in Cumberland in the spring, 

 and leaves it in October or November; and in very mild winters, 

 a 'itiw, I believe, remain with us the whole year. I saw two on 

 the 5th of January this year between the bridges." For some 

 years past I have paid considerable attention to the subject, 

 and 1 am satisfied that some of both remain here even during 

 our most severe winters. In confirmation of which, I have 

 observed both on the several days mentioned below, and have 

 added to each the minimum height of the thermometer. 



1826. November 27. ..22=" 



1824-. December 5... 16° 

 23...24i 



1825. January 6... 25 



23. ..25 

 February 5.. .20 

 Novemberl 2. ..20 



1826. January 10. ..15 



14. ..11 



December 27. ..27 



1827. January 4. ..13 

 27. ..16 



February 20... 16^ 

 November 24...20| 

 December 29...22Jf 



1828. January 11... 14 



lu concluding these desultory observations, it may not be amiss 

 to state that the generic and specific names made use of above, 

 are those adopted by Dr. Fleming in his recent History of 

 British Animals, which contains one of the best and most na- 

 tural arrangement of British birds hitherto publisiied. 



XXXI. On the Laoos of Mortaliti/, and the Intensiti/ of Human 

 Life. By Mr. Francis Corbaux.* 



THE natural law according to which the waste of human 

 life takes place, is the principal regulator of innumerable 

 transactions. Researches of scientific men, long before this 

 subject of consideration had acquired its present and daily^ 

 <Ti-owin<T importance, were directed to ascertiiin the reality of 

 such a law, as expressing with some degree of accuracy the 

 comparative rates of mortality at the successive stages of our 

 lives. Actual experience — die only guide in those researches 



vvas resorted to, but without discriminadon, the necessity of 



which was at first overlooked. Hence the erroneous and al- 

 most unrestricted siip})osition, that a law of mortality inferred 



* CoiiimuniLLitcd h\ t!ic Author, 



from 



