7^ 



NATURE 



{May 23, 1889 



and others don't notice it.' This man was very nervous about 

 crossing the divide at all while it was thundering, and plainly 

 said if there was lightning he must wait for fair weather." 



Possibly, sound might have accompanied this discharge, but' 

 the noise of our wheels would have drowned it. 



Holmwood, Putney Hill, May 19. Dan. Pidgeon. 



Rain-Clcuds, 



The rain-cloud which Mr. Abercromby sketches in Nature 

 of May 2 (p. 12) is often seen in Upper Austria in summer. 

 I have given a rough sketch of these thunder-clouds in the 

 Austrian Mdeorojo^cal Journal, vol. viii., 1873, p. 104. 



Vienna, Hohe Warte 38. juuus Hann. 



THE MUYBRIDGE PHOTOGRAPHS^ 

 TWrR. MUYBRIDGE is of English birth, a citizen of 

 -'■*■»- the Great Republic, and a professional photo- 

 grapher. Long before he applied his knowledge and 

 skill to the subject of instantaneous photography of 

 moving animals and human beings, he had obtained 

 recognition by his work in producing valuable views of 

 Cahfornian scenery, of Panama and the West Indies. 

 In 1872 he made the first lateral photograph of a horse 

 trotting at full speed, for the purpose of setting a con- 

 troversy among horsemen as to " whether all the feet of a 

 horse while trotting were entirely clear of the ground " at 

 at any one instant of time. It was not until 1877, how- 

 ever, that he conceived the idea that animal locomotion, 

 which was then attracting considerable attention through 

 the experiments of Prof. Marey,of the College de France, 

 might be investigated by means of instantaneous photo- 

 graphy, wiih results of value both to the artist and to the 

 naturalist. 



Marey's investigations were made by means of elastic 

 cushions, or tambours, which were placed on the feet 

 of the moving animal, and connected by flexible tubes to 

 pencils writing on a chronograph. A record of the im- 

 pact of each foot on the ground was thus obtained, and 

 important information was deduced from these records 

 as to the succession of footfalls and the time-intervals 

 separating them in the various "gaits" of the horse. 



Mr. Muybridge proposed to settle this and similar 

 problems once for all by a complete and demonstrative 

 graphic method. He arranged a number of cameras 

 side by side, parallel to the track along which a horse was 

 to be ridden. Each camera was provided with a specially 

 contrived " exposer " (the word suggested by Mr. Muy- 

 bridge in place of " shutter"), which could be let go by 

 the pulling of a string. The strings connected with the 

 " exposers " were placed across the path of the horse, so 

 that they must be broken by him successively in his pas- 

 sage. At the instant of the breaking of the string, the 

 exposer was brought into play in the corresponding 

 camera, and thus the horse was photographed in a suc- 

 cession of intervals of about 14 inches, representing, 

 according to the rate of progression of the horse, a time- 

 interval of more or less than one-twentieth of a second. 



In this way, in 1878, with the wet plates then in use a 

 few sets of horses moving with various gaits were taken by 

 Mr. Muybridge. The results were astonishing and con- 

 clusive. They were published at the expense of Mr. 

 Leland Standford, under the title of "The Horse in 

 Motion," and were exhibited in Europe in 1882 by Mr. 

 Muybridge, together with other photographs taken in 

 1879. The reception which Mr. Muybridge met with on 

 his visit to Paris and London was a great encouragement 

 to him to proceed with his work. Meissonier, the great 

 French painter, was enthusiastic in his admission of the 

 value of the photographs as a guide to the observation 

 required for all true artistic work, and the story goes that 



' "Animal Locomotion : an Electro-photographic Investigation of Con- 

 secutive Phases of Animal M vements." By Eadweard Muyb'idge. 

 (Published under the auspices of the L niversity of Pennsylvania, i88S.) 



a particular attitude of the horse presented by him in 

 one of his best known pictures which had been objected 

 to by the critics as unnatural, was demonstrated by the 

 Muybridge photographs to be perfectly correct. The 

 series of little black silhouettes, which were at that time 

 the form in which Mr. Muybridge obtained his pictures, 

 were so contradictory of all preconceived notions as to 

 what were the actual phases of attitude passed through 

 by a trotting or a galloping horse, and so difficult to re- 

 concile with the conventional representations of what is 

 of course a totally different thing, viz. what we see when 

 a trotting or galloping horse crosses our field of vision, 

 that Mr. Muybridge determined on his return to America 

 in 1883 to pursue the subject, and to apply improved 

 methods of photography to the study of the rapid move- 

 ments of a variety of animals and of man. The new 

 dry plates now made it possible to obtain in exposures of 

 I/5COO of a second and less an amount of detail which was 

 previously impossible. New automatic methods of regis- 

 tration and exposure were to be employed, larger pictures 

 obtained, and the selected series printed without re-touch- 

 ing by a permanent photogravure process. The funds 

 necessary to carry out this scheme were beyond Mr. 

 Muybridge's own resources, and he for some time failed 

 to obtain the necessary aid from any publisher or scientific 

 institution. A Committee of the University of Pennsyl- 

 vania thereupon came forward and placed /6000 at Mr. 

 Muybridge's disposal, solely on condition that the first pro- 

 ceeds of the sale of the photographs when ready for publica- 

 tion should be assigned to the reimbursement of this sum. 

 Thevyords of Dr. William Pepper, the Provost of the Univer- 

 sity, in recording this most worthy action, are remarkable, 

 and ably state that conception of the part of the University 

 in the life of the State whicli we have so often advocated 

 in these pages. " The function of a University," says 

 Dr. Pepper, " is not limited to the mere instruction of 

 students. Researches and original investigations, con- 

 ducted by the mature scholars composing its Faculties,, 

 are an important part of its work ; and in a larger concep- 

 tion of its duty should be included the aid which it can 

 extend to investigators engaged in researches too costly 

 or elaborate to be accomplished by private means. When 

 ample provision is made in these several directions, we 

 shall have the University adequately equipped and pre- 

 pared to exert fully her great function as a discoverer 

 and teacher of truth." 



As a result of the action of the University of Pennsyl- 

 vania in providing Mr. Muybridge with the means to 

 carry out his experiments, we have a really marvellous 

 set of plates — 781 in number — each containing a series 

 of from twelve to thirty pictures representing successive 

 instantaneous phases of movement. About 500 of the 

 plates represent men, women, and children, nude and 

 semi-nude, in successive phases of walking,running, jump- 

 ing, dancing, bathing, fencing, wrestling, boxing, and other 

 such exercises. The rest of the plates give similar studies 

 of the various gaits of horses, asses, mules, oxen, deer, 

 elephants, camels, raccoons, apes, sloths, and other quad- 

 rupeds, as well as of the flight of birds. Many of these 

 photographs have been, this spring, exhibited in London 

 by Mr. Muybridge, projected on the screen by electric 

 light — at the Royal Society, the Royal Institution, the 

 Royal Academy, and the South Kensington Art School. 

 The whole series can now be obtained by those who 

 desire to possess them, and to assist the University of 

 of Pennsylvania by bearing a portion of the expense of 

 their production. Series of not less than one hundred 

 plates are also to be disposed of, and may be seen on 

 application to Mr. Muybridge, who is at present in London. 



The interest which these photographs present from thej 

 scientific point of view is threefold : — I 



(A) They, first of all, are important as examples of a| 

 very nearly perfect method of investigation by photo- 

 graphic and electrical appliances. 



