LITERARY NOTICES. 



247 



subject by briefly showing his mode of 

 studying the various paces of the horse. 

 The volume deals systematically and thor- 

 oughly with this whole subject, and is full of 

 novelty and curious interest. Prof. Marey's 

 elucidation of the mechanism of flight in 

 birds and insects is one of the most exqui- 

 site pieces of experimental investigation 

 that modern science affords. The fertil- 

 ity of his devices, by which the varied re- 

 sults are brought out in all their exactness 

 to the eye, by the graphic method of illus- 

 tration, is a source of constant surprise to 

 the reader. He makes pictures of all his 

 facts and laws. Of course the value of such 

 investigations stands upon their own scienti- 

 fic merits, but they have a peculiar attract- 

 iveness as connected with the phenomena 

 of life in which we are all concerned. Yet 

 there can be no greater mistake than to 

 suppose that such researches are destitute 

 of practical utility. Upon this point Prof. 

 Marey has the following excellent remarks 

 in his introduction : 



" The comparison of animals with ma- 

 chines is not only legitimate, it is also ex- 

 tremely useful from different points of view. 

 It furnishes a valuable means of making the 

 mechanical phenomena which occur in liv- 

 ing beings understood, by placing ihem 

 beside the similar but less generally known 

 phenomena which are evident in the action 

 of ordinary machines. In the course of 

 this book, we shall frequently borrow from 

 pure mechanics the synthetical demonstra- 

 tions of the phenomena of animal life. The 

 mechanician, in his turn, may derive useful 

 notions from the study of Nature, which will 

 often show him how the most complicated 

 problems may be solved with admirable 

 simplicity. 



" It is easy to demonstrate the impor- 

 tance of such a subject as locomotion, 

 which, under its different forms, terrestrial, 

 aquatic, and aerial, has constantly excited 

 interest. Whether man has endeavored to 

 utilize to the utmost his own motive power, 

 and that of the animals ; whether he has 

 sought to extend his domain, to open a 

 way for himself in the seas, or rise into the 

 air, it is always from Nature that he has 

 drawn his inspirations. We may hope that 

 a deeper knowledge of the different modes 

 of animal locomotion will be a point of de- 



parture for fresh investigations, whence fur. 

 ther progress will result. 



"Every scientific research has a power- 

 ful attraction in itself; the hope of reaching 

 truth suffices to sustain those who pursue 

 it, through all their efforts ; the contempla- 

 tion of the laws of Nature has been a great 

 and noble source of enjoyment to those who 

 have discovered them. But to humanity, 

 science is only the means, progress is the 

 aim. If we can show that a study may lead 

 to some useful application, we may induce 

 many to pursue it, who would otherwise 

 merely follow it from afar, with the interest 

 of curiosity only. Without pretending to 

 recapitulate here all that has been gained 

 by the study of Nature, we shall endeavor 

 to set forth what may be gained by study- 

 ing it still further, and with more care. 



" If we knew under what conditions the 

 maximum of speed, force, or labor, which 

 the living being can furnish, may be ob- 

 tained, it would put an end to much dis- 

 cussion, and a great deal of conjecture, 

 which is to be regretted. A generation of 

 men would not be condemned to certain 

 military exercises which will be hereafter 

 rejected as useless and ridiculous. One 

 country would not crush its soldiers under 

 an enormous load, while another considers 

 that the best plan is to give them nothing 

 to carry. We should know exactly at what 

 pace an animal does the best service, 

 whether he be required for speed, or for 

 drawing loads ; and we should know what 

 are the conditions of draught best adapted 

 to the utilization of the strength of animals. 



" It is in this sense that progress is be- 

 ing made ; but, if we complain with reason 

 of its slow advance, we must only blame 

 our imperfect notion of the mechanism of 

 locomotion. Let this study be perfected, 

 and then useful applications of it will soon 

 ensue. 



" Man has been manifestly inspired by 

 Nature in the construction of the machinery 

 of navigation. If the hull of the ship is, as 

 it has been justly described, formed on the 

 model of the aquatic fowl, if the sail has 

 been copied from the wing of the swan in- 

 flated by the wind, and the oar from its 

 webbed foot as it strikes the water, these 

 are but a small part of Nature's loans to 

 art. More than two hundred years ago, 



