December, igo6.] 



KNOWLEDGE & SCIENTIFIC NEWS. 



603 



made with propelled balloons, and if such machines are 

 not to be considered as the ultimate ideal of aerial 

 navigation, yet improvements have now been accom- 

 plished in their construction, such as to render them 

 practical engines of war. Count von Zeppelin, the 

 veteran German general, who' has for so manv years 

 been pluckily striving against dilTiculties and misfor- 

 tune, has at last acheived unqualified success with his 

 immense airship, lliis apparatus, as re-constructed, 

 consists of a huge frame-work of aluminium, 430 feet 

 long, over which a smooth outer covering is arranged, 

 and within which, 15 balloons are placed. Tlie two 

 separate engines are each of 85-hor.se power, working 

 four small screws, placed on each side of the vessel. 



The photographs which we reproduce, are of special 

 interest, as having been taken during the process of 

 building the machine, and never before published. 

 Thev clearly show manv of the details of construction. 

 Immense hoops, about 36 feet in diameter, are con- 

 structed of lattice girder-work of aluminium, rivetted 

 together. These are all connected together with a 

 series of longitudinal girders of similar construction. 

 Over this framework is tightly stretched a netting 

 of hemp cord, both inside and outside, so as to 

 make two layers of netting to allow a space between 

 the inner and outer skins. The vessel is further 

 stiffened by trans\erse nettings, forming partitions to 

 keep the internal balloons apart. Over the whole, an 

 outer varnished silk covering is tightly stretched, so as 

 to form a smooth surface to drive through the air. 

 Tlie general shape, as is well-known, is a long cylinder 

 with ogival ends. The extreme point of the bow is 

 formed of a hemispherical aluminium cap, and may be 

 noticed in one of the photographs, where it appears 

 against the light of the sky, almost a.s if unsupported. 



This vast airship underwent manv vicissitudes, and 

 was several times reconstructed, but on the 9th of Octo- 

 ber last, it rose from its platform on Lake Constance, 

 remained for about two hours in the air, manoeuvring 

 over the lake, and finallv, returned safelv to its shed. 

 The maximum speed (taken accurately by theodolites) 

 was 12 metres per second, or just on 30 miles an hour. 

 It has often been remarked that the real test of the 

 practicability of an airship is its ability to attain a suffi- 

 cient speed to stem any ordinary wind. .\ speed of 

 30 miles an hour should certainlv be sufficient for this, 

 and even if the machine is not capable of progressing 

 against a strong wind, still it should be abk' to 

 mancpuvre on any average day. 



The third machine to successfully take the ;iir is th<' 

 new Lcbaudy, " La Patrie," which ha.s been built to the 

 order of the French Government. This is, in general 

 arrangement, very similar to the last Lebaudy, but in- 

 corporates many minor improvements. The volume is 

 3,200 cubic metres, and the engines, of Panhard make, 

 develop 75-hor.se power. 



On November 16, she made her first trial trip, re- 

 maining two hours and 20 minutes in the air, and attain- 

 ing a speed said to be 20 miles an hour. Six passeno'ers 

 were on board. Since then further trials have been 

 made with complete satisfaction, the greatest speed 

 attained being gi\en as 28 miles an hour. Consider- 

 ing the remarkable performances of the first Lebaudv, 

 it is to be hoped th.at this vessel will prove thoroughlv 

 serviceable. 



Thus both the I'leneh and the German armed forces 

 may now be considered to include aerial machines. It is 

 already rumoured that the French are building more, 

 and. without doubt, the Germans and other nations will 

 quickly follow suit. 



The Flight of Flying 

 Fishes^ 



Lt. = Col. Durnford's Arguments. 



From Lieut. -Col. C. D. Durnford we have received a 

 copy of the second paper which he has contributed to 

 the Annals and Magazine of Natural History on " The 

 Flying Fish Problem." Lieut.-Col. Durnford, as 

 readers of the Natural History Notes will be aware, is 

 the opponent of the aeroplane theory of the flying fish's 

 flight, and believes that the flight is accomplished by a 

 very rapid movement of its fin-wings. In a paper pul> 

 lished last January he endeavoured to show that the 

 wing surface of a flying fish was not great enough to 

 support the weight of a flying fish considered as an 

 aeroplane. "The argument was based," to quote the 

 paper before us, " upon the fact that as a flying animal 

 the flying fish is equipped with wings of a fractional 

 sailing value compared with those of a sailing bird. 

 ,\lso that if the wings were many times larger, so as to 

 bring the fish on an equality with the bird in this re- 

 spect, it could only sail with the bird's limitations as 

 regards direction of the wind, and with the bird's fre- 

 quent assistance from rowing flight." 



The difficulty of deciding the vexed question appears 

 to have arisen from the fact that many people, perhaps 

 most people, are unable to perceive the motion of the 

 wings. By Lieut.-Col. Durnford this is attributed to 

 defects of vision, and he remarks that he himself and 

 other witnesses are able to see the movement. One of 

 his latest witnesses has had abundant opportunities of 

 observation during the last year. In a paper dated Octo- 

 ber, 28, 1905, Brig Galilee, North Pacific Ocean, Dr. 

 [. H. Egbert, Carnegie Expedition, writes : " Though 

 still denied by some olDservers, the power of propulsion 

 through the air by means of its fin-wings is generally 

 accorded the flying fish. During- months at sea in the 

 tropics the writer has almost daily watched the flying 

 fishes and studied their flight through the air. . . . 

 The difficulties of assuring oneself that the flying fish 

 moves its wings during its flight through the air are 

 well understood, and also the fact that these difficulties 

 are generally removed when opportunity is afforded of 

 observing the flight of certain of the larger species 

 under favourable conditions. That flying fishes use 

 their wings after the manner of birds, at least upon 

 emerging from the water, can hardly be denied, since 

 from the forecastle head of a ship plying the waters of 

 the lower latitudes this wide birdlike motion of the fin- 

 wings may be easily observed as the large flying fishes 

 bi-eak water almost under the vessel's bow. This 

 flapping motion of the fin-wings is not, however, long 

 maintained, but as soon as the fish is well started in 

 the air apparently passes into a vibratory motion of 

 the appendages so rapid as to be almost lieyond human 

 visual perception." 



Mr. Lionel E. Adams (Zoologiifl, -April 4, 1906) is 

 another witness in favour of Lieut.-Col. Durnford's be- 

 liefs; and, to a slighter extent, Mr. F. G. Aflalo. But 

 the circumstance in which Lieut.-Col. Durnford relies 

 is less that of the perception of the wing movement by 

 observers, than on the impossibility that an aeroplane, 

 whether it were in the form of a bird, a bat, or a flying 

 fish, could glide with and against the wind and at an 

 angle with the wind, and describing curves which 

 would bring it round in a semi-circle — unless it were 

 jiropellcd bv some wing-flapping motion. The follow- 



