BEAVER. 



343 



Thus on this part of the subject there is no need 

 for economy, or saving in any sense of the term. 

 That which the line cannot measure, and the balance 

 cannot weigh, cannot be meted off by the line or 

 weighed off by the balance, so as to diminish its 

 quantity by any nameable fraction of a hairbreadth 

 or a grain. When it works it is never weary; when 

 it gives even to the excess of its bounty, it is never 

 one tittle the less. It stands invisible to every mate- 

 rial sense, unless when displayed in material sub- 

 stance ; but it stands to our mental view as immeasu- 

 rable and immortal ; and though obscured as our 

 mental contemplation is by the material body, we 

 cannot now know and behold it in its essence, yet we 

 dare not say, even if we take the remotest points in 

 time or in space which arithmetic can express or 

 imagination picture, " here it begins, or here it ends." 



But wherever matter is the element, be the appli- 

 cation of that element what it may, we find the most 

 perfect economy exhibited throughout the whole 

 system ; and that whether in what we call mechani- 

 cal structure, or chemical combination, or the action 

 of either or both. In machines which are made by 

 mechanics, those are reckoned the most perfect which 

 are the least loaded with unnecessary parts, or un- 

 necessary weight. From the limited extent of our 

 knowledge, we make but very loose approximations 

 in this way ; and as one part moves fast and another 

 slow, one is exposed to variable and one to uniform 

 temperature, and so forth ; we are unable to adapt the 

 form and the quantity of our materials to these, and 

 therefore the works of our most skilful artists wear 

 out much more in consequence of not being made on 

 true principles, than of what may be termed fair wear. 



In nature it is not so ; for taking the average of 

 nature's productions and of the functions which the 

 parts of them are called upon to perform, there is not 

 a single grain either redundant, defective, or one hair- 

 breadth out of its place. It is this which makes the 

 study of animal mechanics so instructive and so use- 

 ful in every art, and therefore to every man ; though 

 (as has been too often the case in our views of nature) 

 we have done as the ignorant man did with the 

 spy-glass, looked in at the wrong end, and thereby 

 driven away and diminished that which the skilful 

 use of the instrument would have brought nearer and 

 magnified. We have carried the principles and even 

 the applications of human mechanics, as the models 

 in our judgments of nature ; and as these are all im- 

 perfect and really imitations (though frequently un- 

 known imitations) of nature, we have gone about as 

 though we had been to teach nature instead of .learn- 

 ing of her. 



The structure of the beavers' teeth gives us, as we 

 have already seen, the models of some of our mecha- 

 nical instruments in their best forms, though with us 

 they are made of different materials; and as the 

 beaver is, even discounting all the exaggerations 

 which have been related of him, the most mechanical 

 of all the mammalia, we have thought that it would 

 be at once more useful, and savour less of the mere 

 parade of science, to introduce these general observa- 

 tions in our account of the beaver, than in any article 

 more expressly on the subject of animal mechanics, 

 and of the limit beyond which we must not carry our 

 mechanical theory when treating of the structure and 

 economy of animals as they appear to us in wild 

 nature. Having done so, we return to our structural 

 account of the beaver. 



We have already described the teeth; but we 

 must mention several of the other parts before we be 

 in a condition for understanding the habits of the 

 animal ; for, as there is but one species of beaver, 

 and as that species is the same, and inhabits the same 

 kind of localities in all countries in which it is found, 

 it is one of the very best species from the study of 

 which to see clearly the natural connection which 

 subsists between structure and locality. The relation 

 between these, once clearly seen, and well understood 

 in one instance, can with much safety be carried to 

 other instances, and forms at once one of the securest 

 and the most instructive of analogies. 



The beaver is low and squat in its body; the line 

 of its profile from the occiput to the muzzle is un- 

 broken ; the muzzle is oblique and blunt; and the 

 upper lip cleft, as in the hare. The eyes are small, 

 oblique, and wide apart from each other; and the 

 ears also are small. The fur is remarkably close and 

 soft ; but interspersed with longer bristly hairs, which 

 get more abundant as the animal grows older; both 

 the hind and the fore legs seem short in proportion 

 to the size of the animal when it walks on the ground ; 

 but, as is the case with all animals of the order, the 

 habit of which is generally to leap, to stand up, or to 

 support themselves on their hind legs, these are much 

 longer than the fore ones. They are, however, dif- 

 ferently articulated, especially at the knee joints, 

 which turn inwards, as in a man who is what is called 

 " knock-kneed," and thus the hind feet are shambling 

 and wide apart from each other in walking, though 

 in their other function of swimming they answer 

 better in consequence of this mode of articulation. 

 Swimming feet, and especially the hind feet of swim- 

 ming mammalia, are always constructed in this man- 

 ner, except in those species in which (as in the seal, 

 for instance) they are formed into a swimming sail, 

 and in consequence of this they act more horizon- 

 tally, and consequently impel the animal forward in 

 the water with more velocity by less exertion. Ani- 

 mals which are constructed principally for walking 

 on the land, make the chief exertion with the fore 

 feet when they swim ; and therefore they are sooner 

 fatigued than when they move even faster upon land ; 

 but quadruped animals having a regular swimming 

 habit, impel themselves chiefly by means of the hind 

 feet, and on this account they are no more fatigued 

 in the water than they are on land. The reason of 

 this will be readily understood by those who are 

 aware how much more easily a boat is pulled by oars 

 nearly on a level with the water, and near the quar- 

 ters, than by oars which have to dip much downwards 

 and are used near the bows. 



The beaver has this swimming property of the hind 

 feet in greater perfection than almost any other quad- 

 ruped ; because when making way by means of these, 

 it often has occasion to use the fore feet for purposes 

 not connected with swimming, such as in assisting 

 in moving along billets of wood, stones, or such 

 other matters as the animal requires for its food 

 or its buildings. These feet in the beaver are in 

 consequence rather more awkward upon land than 

 any other feet of the same length and muscular 

 power ; but, generally speaking, it is in the water 

 that the beaver performs the more arduous portion 

 of its labours, and the instruments of motion in that 

 element are best adapted for it. There are five toes 

 on each of those hind feet, which are free in the joints 



