8 4 



NATURE 



{May 25 188,2 



1879 Co1 - Rykatchoff, of the St. Petersburg Central Phy- 

 sical Observatory, established, on board the Nayezdnik, 

 an anemometer of his own construction, which was ob- 

 served during the ocean cruise of the clipper ; and the 

 schooner Nordenskjold, which unhappily was lost in 1S79 

 at Yesso Island, had also an anemometer, which was 

 taken afterwards on board the Russian clipper Djighit 

 by M. Domojirov. The observations on board of the 

 Djighit were carried on with this anemometer (of Casella) 

 put in such an apparatus (like that of the lamps on board 

 of ships), as always maintained it in a vertical position, 

 even during the heaviest seas, when the ship oscillated 

 for 30 on one side, and 35° on the other. The apparatus 

 was put on a 16-foot-long pole, which was pushed out for 

 each observation on the wind-side of the ship, from the 

 boat, and thus exposed to the full force of the wind for 

 ten minutes. The height of the instrument above the sea 

 was 26 feet. The direction of wind was determinated by 

 means of a vane, and its true direction computed from 

 the apparent one, on the principle of the parallelogram of 

 forces, by taking into account the velocity of the ship. 

 When the angle between the direction of the wind and the 

 direction in which the ship goes is known, as well as the 

 seeming velocity of wind (measured by the anemometer), 

 and the velocity of the ship, the true velocity of wind is 

 easily determined by means of simple computations, or of 

 the tables published for that purpose by M. Rykatchoff 

 (Russian Marine Review, February, 1SS0). A series of 

 experiments having been made for ascertaining in how 

 far the calculated figures agree with the true ones, M. 

 Domojirov arrives at the conclusion that these figures 

 are quite reliable ; determination having been made 

 during the progress of the ship, she was immediately 

 stopped, and the determination made anew, both results 

 always being quite identical. But the measurements 

 from the side-boat are very tedious and even dangerous 

 during heavy seas, and each observation occupies no less 

 than three men for about twenty minutes. Therefore M. 

 Domojirov proposes to apply electricity to register the 

 rate of the anemometer. 



The observations on board the Dji^liit were made five 

 and six times per day from March 23 to May 30, and the 

 complete results, with all elements for calculations, are 

 published in the papers of M. Domojirov. The north- 

 eastern trade-wind, observed on the passage from Japan 

 to the Sandwich Islands and back, had a very regular 

 force of from 5 to 9 metres per second ; the south-eastern 

 trade-wind experienced on the passage from the Sunda 

 Islands to the Seyschels, had a velocity of 4 to 9 metres 

 per second, and the south-western wind's on the passage 

 from Port Victoria to Aden, had velocities from 12 to 15 

 metres per second. 



It would hardly be necessary to in-:i-t on the importance 

 of such observations for mcteorologv. as well as for prac- 

 tical purposes, and we hope that soon the still prevailing 

 prejudices as to the possibility of anemometrical observa- 

 tions on board ships having disappeared, and more con- 

 venient methods of observaticn having been devised, the 

 anemometer will become on board ships as necessary an 

 instrument as the log and barometer. P. K. 



INSTANTANEOUS PHOTOGRAPHY OF 

 BIRDS IN FLIGHT 



OROF. E. J. MAREY has lately published in the pages 

 of our contemporary, /.,; Nature, an article on a "pho- 

 tographic gun,'' the illustrations to which, with a somewhat 

 shortened account of the process, we are enabled, through 

 the courtesy of the editor of La Nature, to present to our 

 readers. M. Marey's researches on animal locomotion are 

 well known ; his experiments carried on bv the graphic 

 method were productive of most valuable results, and 

 ihey con- M | a im .1 mam debated pi 



animal mechanics ; but having seen some of the results 

 obtained by Mr. Muybridge, at San Francisco, with pho- 

 tographic pictures taken during an exposure of the l-500th 

 of a second, he was very desirous to have the same process 

 adapted, so as to admit of its being applied to the taking 

 of birds flying. In September, 18S1, on a visit of Mr. 

 Muybridge to Paris, he brought with him some photo- 

 graphs of birds taken on the wing, but these unlike the 

 invaluable series taken by the same gentleman of horses 

 and men, were not the representation of a series of con- 

 tinuous attitudes, but rather represented thebird in (Deposi- 

 tion it happened to be in at a moment of time ; whereas, to 

 explain the fail and rise of the wings and the positions of 



Fig. i.— The Photographic Gun. 



the body, it was, above all things, important to have a 

 series of rapid photographs taken of the same bird over 

 a period during which the whole mechanism was in 

 action, so as to allow of the movements to be afterwards 

 studied at leisure. After deliberating over this subject 

 during the last winter, at last the idea of a photographic 

 gun oci urred to him ; but the immense quickness with 

 which the movements should succeed one another, in 

 order to bring .1 series of sensitive surfh :es across the lens, 

 at first presented great difficulties in the constructing of 

 the machine. It was necessary to have images taken suc- 

 • s-" t Ij t< n or twelve tur.es in one second, in order to 



