82 



POPULAR SCIETsTCE ISTEWS. 



[June, 18S9. 



should be taken to remove all other objects 

 from the field of view, or the deception would 

 be apparent at once. 



An ingenious Frenchman, M. Batut, has 

 succeeded in attaching a camera to a kite, and 

 thus obtaining pictures at a considerable alti- 

 tude. The arrangement is shown in Fig. 4. 



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( Induit 



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I Inducteur I 



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Fig. 6. 



The kite is seven and a half feet long, and is 

 provided with a long and heavy tail, to ensure 

 stability while in the air. The string is 

 attached to a bar of wood (T), and is so 

 arranged that it does not interfere with the 

 field of view. B is a small aneroid barome- 

 ter, to indicate the height of the kite. It is so 

 arranged that, at the moment of exposinx', the 

 position of the pointer is also photographed, 

 thus giving a record of the distance of the 

 kite above the earth. The camera itself is 

 furnished with an instantaneous spring-shutter, 

 giving an exposiu'e of about a hundredth of a 

 second. It is liberated by a time-Iuse (C), 

 which is lighted before the kite leaves the 

 ground. The movement of the shutter also 

 liberates a roll of paper, which uncoils and 



three-quarters pounds, but this can be reduced 

 by omitting the barometer, which is quite 

 unnecessary for ordinary purposes. 



In former numbers of the Science News, 

 we have reproduced photographs, of electric 

 sparks of various sizes and intensities. These 

 were taken with a camera, in the oi'dinary 

 way, but the beautiful sparks represented in 

 the accompanying illustrations, impressed 

 themselves directly upon the sensitive photo- 

 graphic plate. Fig. 6 shows the arrangement 

 of the apparatus. The sensitive plate (a) 

 was placed upon a much larger piece of 

 ebonite (1^), which rested upon a small me- 

 tallic disk (c), attached to an insulated stand 

 {d.) It will thus be seen that the sensitive 

 plate really formed one surface of an electrical 

 condenser, like the coating of a Leaden jar. 

 The poles of a powerful induction coil, capa- 

 ble of giving a spark six inches long, were 

 then connected. — one to the lower metallic disk. 



Fig. 7. 



indicates to those below that the exposme is 

 completed. Fig. 1^ is a fac-.simile of a photo- 

 graph obtained in this way, at a height of 

 four hundred feet, showing the roofs of a 

 farm-house and out-buildings, with a part of 

 the adjoining fields. The total weight of the 

 photographic apparatus is about two and 



Fig. 8. 



and the other to the centre of the sensitive 

 plate. A single spark was then allowed to 

 pass, and the plate developed in the usual 

 way. Figs. 7 and 8 are fac-similes of the 

 photographs thus obtained ; the first when the 

 positive electrode was connected with the 

 plate, and the second when the negative one 

 was used. The difierence between the two 

 poles is very striking. Similar results could 

 doubtless be obtained with less powerful in- 

 duction coils, by using a smaller photographic 

 plate, it being only necessary that the spark 

 should be of sufficient intensity to pass from 

 one electrode to the other, over the sensitive 

 surface. 



These photographs were taken by M. 

 Rouille, whose original paper appeared in 

 /.a JVaturc, to which joiunal we are indebted 

 for the illustrations accompanying this article. 



Seeds of the most valuable varieties of cinchona 

 bring $i,ot)o per ounce in Ceylon. There are nearly 

 100,000 seeds in an ounce. 



[Original in The Popular Science A'ews.\ 

 EVOLUTION. 



BY PROFESSOR JAMES II. STOLLER. 



THIRD TAl-ER. 



EVOLUTION IN ORGANIC NATURE. 



In the last paper we saw that evolution appears to 

 be a universal law in physical nature ; a law by 

 which all the heavenly worlds were fashioned out of 

 a primordial fire-mist, and by which, out of one of 

 these revolving molten balls, our earth, with its 

 present manilold diversity of features, was built up. 

 We are now to leave the realm of inorganic nature, 

 and pass to that of the organic. We are to consider 

 whether the countless thousands of living creatures 

 of which the earth is the home, are also the product 

 of a great law of evolution. More definitely stated, 

 our inquiry is, whether the plants and animals now 

 living have been derived by natural descent from 

 others specifically different from them, and these 

 likewise from others, and so on, back through lower 

 and lower specific forms, to organisms of the sim- 

 plest nature, which were the primordial living 

 beings. In other words, the question is, w hether all 

 the million varied forms of animate nature are 

 bound together by actual derivational relationship 

 into one great iamily. 



Let us look at the question from still anotlier 

 point of view. When our earth had so far evolved 

 from its primal_ condition of a molten mass as to 

 become a sphere with a cooled land-and-water surface, 

 it became capable of supporting life. Now, suppos- 

 ing the first forms of lite to have come into exist- 

 ence, (in what way, we need not consider at present), 

 did these forms give rise to others by a natural pro- 

 cess.' Were they the ancestors of all the succeeding 

 generations of living things, from that day down to 

 the present.' Have organic forms, beginning with 

 these primordial organisms, succeeded one another 

 progressively, in divergent lines, and altogether 

 according to natural laws.' 



To this question modern science makes answer by 

 pointing to a vast array of definitely observed facts, 

 which find an adequate explanation in an hypothesis 

 of organic evolution, and admit of no other expla- 

 nation. The.se facts relate to the bodily structure 

 of plants and animals, to their history in geologic 

 time, to their individual life-history or embryology, 

 to their geographical distribution, etc. It is to the 

 evidence afforded by these several classes of facts 

 that attention must be given in order to understand 

 the scientific doctrine of organic evolution. Wc 

 shall consider this evidence under its several heads, 

 as follows : 

 JScidences of VoinpayatiL-e Atitifomi/. 



It is within common observation that groups of 

 animals widely dillerent in secondary characters, as 

 size, habits, etc., yet show close similarity in 

 bodily structure. Take, for example, the sheep and 

 the ox : they are not only alike in being vertebrates 

 and mammalians, but in having cloven hoofs, a pair 

 of horns, lower jaws destitute of incisor teeth, a 

 four-fold stomach, etc. These marks of affinity sug- 

 gest that they are actually related in derivation; in 

 other words, that the two sorts of animals are diver- 

 gencies from a common ancestral type. If we com- 

 pare animals having still stronger structural resem- 

 blances, though belonging to distinct sjiecies or 

 genera, — as, for example, frogs and toads, — the same 

 suggestion presents itself with greater force. How- 

 ever, it is by comparing the corresponding organs 

 or parts of the bodies, rather than of the bodies in 

 their entirety, that an identity of structural plan 

 shows itself most clearly. For instance, the fore- 

 limbs of the dog, the horse, the sheep, the ape, and 

 the arm of man, are made upon exactly the same 

 plan — have precisely corresi)onding parts. The 



