21 S 



KNOWLEDGE. 



[Octoher 1, 1895. 



embrace roots, leaves, and fruits. Ignorance on this 

 point has often led to fatal results. Every season has its 

 victims, who are chiefly town-bred ; for country children, 

 who eat a great variety of vegetable products, from pig-nuts 

 to hips and haws, to say nothing of the more luscious berries 

 of various kinds, are early taught by tradition that certain 

 plants are poisonous. 



Another branch of botany requiring little mental efibrt to 

 master its general principles, is the geographical distribution 

 of plants. Taking the British flora, for example, as a basis, 

 it is something to know that it does not contain a single 

 peculiar species of flowering plants — at least no very 

 decidedly distinct species — and that it forms part of a flora 

 that stretches from the Atlantic eastward to the Pacific, 

 and, in a less pronounced degree, all around the northern 

 hemisphere ; that it also has the widest latitudinal 

 extension of any flora, remains of it occurring on the 

 mountain ranges of America, Africa, and Asia, southward 

 to Cape Horn, the mountains of tropical Africa, and 

 Australia and New Zealand; that the common "ladies' 

 mantle" is found on the Australian Alps, and that a 

 primrose abundant in the extreme south of America is 

 hardly distinguishable from Frimula [((linnm of the north 

 of England ; and, finally, that there is a greater variety of 

 beech trees in South America, New Zealand, and south- 

 eastern Australia than in the northern hemisphere. A 

 person whose knowledge of botany is of the kind indicated 

 in the foregoing remarks is in a better position than the 

 " pot and pan " botanist whose education does not include 

 these commonplace facts. The examiners in botany of the 

 Science and Art Department have recognized the impor- 

 tance of knowing these small things by setting a question 

 this year on culinary botany-, in which the candidate is 

 asked to state what part of the plant is eaten of a number 

 of difi'erent vegetables. 



THE FIELD-NATURALIST AND THE CAMERA. 

 THE KESTREL HAWK. 



By Harry F. Witherby. 



THE usefulness of photography as an aid to science 

 is not yet, perhaps, thoroughly appreciated, nor 

 have its applications been exhausted. We have 

 long known it to be of the greatest possible help 

 in astronomy, microscopy, and other sciences, but 

 as an aid to the study of birds and animals, photography 

 is still in its infancy. We feel sure that when properly 

 taken up by field-naturalists, it will be found to be an 

 exceedingly valuable adjunct to the gun and field-glass. 



Several reproductions of photographs taken from life, of 

 birds and animals, have already appeared in Knowledge 

 during the last two years, and this month an enlarged 

 reproduction of a photograph of some young kestrel hawks 

 in their nest is put before the reader. 



About four o'clock one bright, sunny morning in June, 

 when taking a stroll in a beautiful park in Ireland, I met 

 one of the keepers of the place, who ofl'ered to show me a 

 kestrel's nest. Arriving at the fir tree in which the 

 kestrels were, I began at once to climb, and had 

 gone some distance up the trunk before the hen bird 

 liew off, so closely did she sit. Li one of the boughs 

 near the top of the tree, about forty feet from the 

 ground, there was a dense growth of twigs about a 

 foot high, and on a platform in the midst was what at 

 first sight looked like a mass of yeUowish down. This 

 proved to be six young kestrels, so mixed up together, and 

 so plentifully plumaged, that it was diflicult to count them 



or to say which hooked beak or curved claw belonged to 

 which ball of down. When touched they began to cry 

 plaintively, and this brought an answering note of alarm — 

 a sharp kee, kee, kee— from the hen bird which was flying 

 about not far away. 



The imique position of the nest, and the beautiful stage 

 of plumage in which the young birds were, suggested the 

 idea of photographing them. The advantages of the 

 position were many — the tree was a fairly isolated one and 

 well exposed to the light ; the nest, being a mere platform 

 of twigs, was not deep enough to hide its contents, while 

 the branches over it were not thick enough to obscure 



Youni; Kestrels aud Xcst in Fir Tru 



the needed light, and the tree was easy to climb. 

 This last fact enabled me to go up to the nest at 

 various times of the day to select the best light, and 

 accordingly at about eleven o'clock the next morning I 

 climbed up the tree with hand-camera, rope, and saw. 

 First some boughs had to be cut ofl' to let in more light 

 upon the nest, and others had to be tied back for the same 

 reason. It was impossible to take the photograph from 

 the side nearest the tnmk, owing to the thick growth of 

 twigs. On the further side, the bough, which was in no 

 place very thick, divided off into three branches. Here 

 the usefulness of the rope came in, for passing it round 

 the trunk of the tree and myself, the thin boughs were 

 freed of a good deal of weight, and I was enabled to use 

 both hands to the camera. When the latter was brought 

 to bear on the birds a great many twigs were found to be 

 in the way, so the camera had to be balanced on a branch, 

 the rope unlashed, and the saw brought into use again. 

 At last when everything was ready the sunhght disap- 

 peared ! After I had waited a quarter of an hour in a very 

 cramped position, the sun shone again, the birds were 

 tickled with a twig into a good attitude, and eight or ten 

 plates were exposed. Not feeling quite sure that the 

 camera was far enough away from the subject to be in 

 focus, I measured the distance and found it to be a foot 

 too near for the focus of the lens. So all the photo- 

 graphs taken, as was afterwards proved in developing, 

 were useless. It was not easy to get back another foot, 

 and retreating cautiously, I found that my weight bent 

 the boughs down so far that the camera could not be 

 held high enough to take in the picture. A happy idea 

 then occurred to me. I regained my former position 



