66 love's meinie. 



grew's on the Wing; '^ — and now I must qnalify my praise 

 considerably, discovenng, when I examined the book far- 

 ther, that the good doctor had described the motion of a 

 bird as resembling that of a kite, without ever inquiring 

 what, in a bird, represented that somewhat important part 

 of a kite, the string. You will, however, find the book full 

 of important observations, and illustrated by valuable draw- 

 ings. But the point in question you must settle for your- 



* ' ' On the Physiology of Wing-s. " Transactions of the Royal Society 

 of Edinburgh. Vol. xxvi. , Part ii. I cannot sufficiently express either 

 my wonder or regret at the petulance in which men of science are con- 

 tinually tempted into immature publicity, by their rivalship with each 

 other. Page after page of this book, which, slowly digested and taken 

 counsel upon, might have been a noble contribution to natural history, 

 is occupied with dispute utterly useless to the reader, on the question 

 of the priority of the author, by some months, to a French savant, in 

 the statement of a principle which neither has yet proved ; while page 

 after page is rendered worse than useless to the reader by the author's 

 passionate endeavour to contradict the ideas of unquestionably previous 

 investigators. The problem of flight was, to all serious purpose, solved 

 by Borelli in 1680, and the following passage is very notable as an 

 example of the way in which the endeavour to obscure the light of 

 former ages too fatally diras and distorts that by which modern men of 

 science walk, themselves. " Borelli, and all who have written since his 

 time, are unanimous in affirming that the horizontal transference of 

 the body of the bird is due to the perpendicular vibration of the wings, 

 and to the yielding of the posterior or flexible margins of the wings in 

 an upward direction, as the wings descend. I" (Dr. Pettigrew) "am, 

 however, disposed to attribute it to the fact (1st), that t/ie wings, both 

 when elevated and depressed, leap foricards in curves, those curves 

 uniting to form a continuous waved track ; (2nd), to the tendency wMch 

 tlie body of the bird has to sicing forwards^ in a more or less horizontal 

 direction, xclien once set in motion ; (3rd;, to the construction of the 

 wings ; they are elastic helices or screws, which twist and untwist 

 while they vibrate, and tend to bear upicards and onwards any weight 

 suspended from them ; (4th), to the reaction ofths air on the under sur- 



