8432 Notices of New Books. 



with the birds I have mentioned, all of which freely eat insects through- 

 out the breeding season. Taking still another view of the subject 

 nothing is more likely, I might almost say more a matter of course, 

 than that in a group so diversified as the humming birds there should 

 be a division feeding on flies and another on spiders, and that neither 

 of these facts should in any way interfere with the normal mellivorous 

 propensity of the tribe implied in the extraordinary structure of the 

 tubular tongue. 



I am well aware how common it is for the man of straw in the 

 critic's chair to assume a knowledge superior to that of the author he 

 is reviewing. I will not fall into that error. Knowing how perfectly 

 Mr. Gould has informed himself on all these points, I take it for 

 granted he is scarcely open to contradiction on matters of fact ; neither 

 do I know from what other source I could obtain reliable statements 

 opposed to anything he has advanced had I desired to do so. The 

 suggestions I make have a wider scope and more general bearing than 

 the pleasure of detecting an error of fact or of pointing out an incon- 

 sequent inference. 



Flight of Humming Birds. — <e How wonderful must be the mecha- 

 nism which sets in motion and sustains for so lengthened a time the 

 vibratory movements of a humming bird's wing ! To me their action 

 appeared unlike any thing of the kind I had ever seen before, and 

 strongly reminded me of a piece of machinery acted upon by a power- 

 ful spring. I was particularly struck by this peculiarity in the flight, 

 as it was exactly the opposite of what I expected. The bird does not 

 usually glide through the air with the quick darting flight of a swallow 

 or swift, but continues tremulously moving its wings while passing 

 from flower to flower, or when taking a more distant flight over a high 

 tree or across a river. When poised before any object this action is 

 so rapidly performed that it is impossible for the eye to follow each 

 stroke, and a hazy semicircle of indistinctness on each side of the bird 

 is all that is perceptible. Although many short intermissions of rest 

 are taken during the day the bird may be said to live in air, an element 

 in which it performs every kind of evolution with the utmost ease, fre- 

 quently rising perpendicularly, flying backward, pirouetting or dancing 

 off as it were from place to place, or from one part of a tree to another, 

 sometimes descending, at others ascending ; it often mounts up above 

 the towering trees, and then shoots off like a little meteor at a right 

 angle ; at other times it quietly buzzes away among the little flowers 

 near the ground ; at one moment it is poised over a diminutive weed, 

 at the next it is seen at a distance of forty yards, whither it has vanished 



