5i6 



NATURE 



\Oct. 29, 1874 



(1) Discussion of the thunderstorms {praoes) of these 

 years, illustrated with forty-six maps. (2) Hailstorms, 

 with three maps. This part of the work, which is of so 

 much importance to agriculture, has been unfortunately 

 neglected for some time, but is now to be vigorously 

 prosecuted. (3) Report on the climatic observations 

 made in France, and particularly on the distribution of 

 rain, with four maps. (4) Meteorological memoirs and 

 documents (thirteen in all), contributed by different 

 meteorologists of France and other countries, a section of 

 the work which is expected to receive a fuller development 

 in future issues.* 



A noteworthy feature of the publication consists in the 

 fact that the materials which make it up have been 

 collected under the auspices of the Departmental Com- 

 missions, and in great part discussed by them. This is, 

 particularly for such a country as France, an admirable 

 arrangement, since there is no European country the 

 working out of the meteorology of which presents a 

 more complex problem, owing to the great diversity of the 

 climates of its different regions ; and further, the agricul- 

 tural interests of no other country would benefit more than 

 those of France, were a correct knowledge of its climate 

 generally disseminated among the people. Now, this 

 feature of the publication gives the local colouring to the 

 reports which is fitted to arrest general attention and 

 secure the putting forth of those local efforts by which 

 alone the meteorology of France can be satisfactorily 

 worked out. 



It may be here pointed out that the French meteorolo- 

 gical organisation is based on, the Commissions which 

 have been appointed in each of the departments ; it 

 being to them that the Government, in the decree of 

 Feb. 13, 1S73, has remitted the working out of the 

 meteorology of the different river-basins, and inquiries 

 connected therewith. They are invited to unite together 

 for certain objects into Regional Commissions, for the 

 purpose of imparting to their investigations greater 

 breadth and exactness. They are not put under the 

 Central Administration at Paris in the sense of being 

 controlled by it, but are connected with it in order that 

 they may be aided by it in cases where aid is needed. 

 The Departmental Commissions have free automatic 

 action in working out the problem of the local climates 

 of the respective districts which have been entrusted to 

 them. 



The programme assigned to the Central Observatory of 

 Paris, consisting of the investigation of the great move- 

 ments of the atmosphere, and meteorological warnings 

 for the seaports and for agriculture, is too limited in its 

 scope ; and we cannot suppose that its illustrious head 

 will be satisfied till he has succeeded in including in the 

 regular work of the Observatory those physical researches 

 we have already strongly advocated in Nature (vol. x. 

 p. 99) as an indispensable part of the work to be under- 

 taken by the Central Meteorological Office of each country, 

 and which have been more recently and ably stated by 

 Prof. Balfour Stewart and Col. Strange (pp. 476 and 490). 



In the same article we urged the necessity of the State 

 and the country working together ; indeed, in no other 

 way is it possible successfully to work out the great 



» The price of the 



(12 fr.) 



c, post-free to England, is, we understand, i 



national questions of storms and of local climates in 

 their bearings on the health, productions, and com- 

 merce of the country. In France we see that this 

 essential requisite, of the State and the country working 

 together, has been effected, and it may not be irrelevant 

 to add that the French Government has clearly re- 

 cognised the position that unaided voluntary efforts 

 are insufficient of themselves to cope with the subject, 

 and that if the undertaking is to be conducted in 

 a manner worthy of the nation and of the ends to be 

 subserved by it, it must be supported with aid from the 

 public funds. 



MA KEY'S ''ANIMAL MECHANISM"* 

 Animal Mechanism. By E. J. Marey. " The Inter- 

 national Scientific Series." (London : Henry S. King 

 and Co., 1874.) 



II. 



IN his treatment of aerial locomotion, Prof. Marey has 

 been even more successful than in his investigations 

 with regard to progression on land. Nearly two centurits 

 ago the general,' principles of this subject were very ably 

 worked out by Borelli, who, after having shown that in the 

 wing the anterior margin is rigid whilst the posterior 

 portions are more and more flexible as they go backwards, 

 inferred, as v/ill be self-evident to all, that in the down- 

 ward stroke of the flying bird the plane of the wing 

 becomes directed downwards and backwards on account 

 of the hinder margin yielding slightly to the resisting air. 

 It not having struck him that the wing was elastic in its 

 horizontal as well as its vertical direction, Borelli assumed 

 that the stroke was strictly vertical. 



By a series of experiments, the logical sequence and 

 convincing power of which are perhaps unequalled in any 

 other extant biological problem. Prof Marey has been 

 able to demonstrate the effects of the horizontal yielding- 

 ness of the wing, and to prove that in insects the stroke, 

 instead of being, as Borelli assumed, a simple vertical 

 line, is a vertical figure of S. In proof of this original and, 

 at first sight, unexpected observation, he shows that if the 

 tip of the wing of a wasp be gilt, and the insect allowed 

 to buzz n a beam of sunlight, a very elongated vertical 

 figure of S image is seen, as in Fig. i, to be produced by 

 the reflecting tip of the rapidly moving wing ; " sometimes, 

 indeed, the wing seems to move entirely in one plane, and 

 the instant afterwards the terminal loops which form the 

 8 are seen to open more and more. When the opening is 

 very large, one of the loops usually predominates over the 

 other ; it is generally the lower one which increases, 

 while the upper diminishes. Indeed, by a still greater 

 opening, the figure is occasionally transformed into an 

 irregular ellipse, at the extremity of which we can recog- 

 nise a vestige of the second loop." 



There is still more to be learnt from this simple experi- 

 ment. By carefully gilding one surface of the wing alone, 

 the buzzing wing, when intensely illuminated, exhibits the 

 figure of S of unequal intensity in its two moieties, as seen 

 in Fig. I ; so that it resembles the figure printed thus, Hj 

 if its thick part be considered to represent that which 

 is most illuminated, and its thin part the darker half. 

 This result can only be produced by the plane of the 



* Continued from p. 500. 



