14 



ON THE WALK OF QUADRUPEDS. 



years old, such as are killed on the great lakes of Switzerland and 

 Italy. It should be understood that the species which do not continue 

 their periodical journey so far as the North Sea and the Baltic are 

 exceptions ; the old ones among the latter never stray to the northern 

 climates, and it would be an extremely rare circumstance to find a 

 young one there. 



ON THE WALK OF QUADRUPEDS. 



BY J. A. BORELLI, PROFESSOR OF MATHEMATICS, NAPLES.* 



Distinguished philosophers and anatomists, no less than the un- 

 learned, have fallen into gross mistakes upon this subject, in conse- 

 quence of trusting to theoretical opinion, rather than to the evidence 

 of observed facts. 



PROPOSITION. 



The step of quadrupeds is not performed by alternately lifting the 

 two feet diagonally opposite, [that is, right and left, or left and 

 right, Edit.] vjhile the other two remain attest. 



An opinion prevailed that the step of quadrupeds was performed by 

 the moving forwards of two feet together, alternately with the two that 



* Translated from the Latin work, " De Motu Animalium," by John Sharp, Esq. 



