OBJECTS, PLEASURES, AND ADVANTAGES OF SCIENCE. xxi 



necessary to destroy these nests, by raising a sufficient force to dig a trench all round, and fill it with fagots, 

 which were afterwards set on fire ; and then battering with cannon from a distance, to drive the insects out 

 and make them run into the flames. This was in South America ; and African travellers have met them in 

 the same formidable numbers and strength. 



The older writers of books upon the habits of some animals, abound with stories which may be of doubtful 

 credit. But the facts now stated respecting the Ant and Bee, may be relied on as authentic. They are the 

 result of very late observations, and experiments made with great accuracy by several most worthy and intelli- 

 gent men; and the greater part of them have the confirmation arising from more than one observer having 

 assisted in the inquiries.* The habits of Beavers are equally well authenticated, and, being more easily 

 observed, are vouched by a greater number of witnesses. These animals, as if to enable them to live and move 

 either on land or water, have two web-feet like those of ducks or water-dogs, and two like those of land 

 animals. When they wish to construct a dwelling-place, or rather city, for it serves the whole bodv, they choose 

 a level ground with a stream running through it; they then dam up the stream so as to make a pond, and perform 

 the operation as skilfully as we could ourselves. Next they drive into the ground stakes of five or six feet 

 long in rows, wattling each row with twigs, and puddling or filling the interstices with clay, which they 

 ram close in, so as to make the whole solid and water-tight. This dam is likewise shaped on the truest 

 principles; for the upper side next the water slopes, and the side below is perpendicular: the base of the 

 dam is ten or twelve feet thick ; the top or narrow part two or three, and it is sometimes as long as one 

 hundred feet.f The pond being thus formed and secured, they make their houses round the edge of it ; 

 ;hey are cells, with vaulted roofs, and upon piles : they are made of stones, earth, and sticks ; the walls are 

 two feet thick, and plastered as neatly as if the trowel had been used. Sometimes they have two or three 

 stories for retreating to in case of floods ; and they always have two doors, one towards the water and ono 

 towards the land. They keep their winter provisions in stores, and bring them out to use ; they make their 

 beds of moss ; they live on the bark of trees, gum, and crawfish. Each house holds from tweuty to thirty, 

 and there may be from ten to twenty-five houses in all. Some of their communities are larger than othersi 

 but there are seldom fewer than two or three hundred inhabitants. In working, they all bear their shares; 

 some gnaw the trees and branches with their teeth, to form stakes and beams ; others roll the pieces to 

 the water ; others, diving, make holes with their teeth to place the piles in ; others collect and carry stones 

 and clay ; others beat and mix the mortar ; and others carry it on their broad tails, and with these beat it 

 and plaster it. Some superintend the rest, and make signals by sharp strokes with the tail, which are care- 

 fully attended to ; the beavers hastening to the place where they are wanted to work, or to repair any hole 

 made by the water, or to defend themselves or make their escape, when attacked by an enemy. 



The fitness of different animals, by their bodily structure, to the circumstances in which they are 

 found, presents an endless subject of curious inquiry and pleasing contemplation. Thus, the Camel, which 

 lives in sandy deserts, has broad spreading hoofs to support him on the loose soil ; and an apparatus in his 

 body by which water is kept for many days, to be used when no moisture can be had. As this would bo 

 useless in the neighbourhood of streams or wells, and as it would be equally so in the desert, where no water 

 is to be found, there can bo no doubt that it is intended to assist in journeying across the sands from ono 

 watered spot to another. There is a singular and beautiful provision made in this animal's foot, for enabling 

 it to sustain the fatigue of journeys under the pressure of its great weight. Besides the yielding of the 

 bones and ligaments, or bindings, which gives elasticity to the foot of the deer and other animals, there is 

 in the Camel's foot, between the horny sole and the bones, a cushion, like a ball, of soft matter, almost 

 fluid, but in which there is a mass of threads extremely elastic, interwoven with the pulpy substance. The 

 cushion thus easily changes its shape when pressed ; yet it has such an elastic spring, that the bones of the 

 foot press on it uninjured by the heavy body which they support, and this huge animal steps as softly us 

 a cat. 



Nor need we fleo to the desert in order to witness an example of skilful structure; the limbs of 

 the Jlorte display it strikingly. The bones of the foot are not placed directly under the weight; if they 

 were in an upright position, they would make a firm pillar, and every motion would cause a shock. They 

 are placed slanting or oblique, and tied together by an clastic binding on their lower surfaces, so as to 

 form springs as exact as those which we make of leather and steel for carriages. Then the flatness of the 

 hoof, which stretches out on each side, and the frog coming down in the middle between the quarters, 

 adds greatly to the elasticity of the machine. Ignorant of this, ill-informed farriers nail the shoe in such a 



* A singular circumstance occasioned this in the raw of Mr. Hubcr, by far the most eminent of these naturalists: he was quite 

 blind, and performed all hit experiments by means of assistants. 



+ If the basr be twelve, and the top three feet thick, and the hcieht six feet, the face must be the side of a right-angled triangb 

 whose height is fight feet. This would be the exact proportion which there ought to be, upon mathematical principle*, to give 

 the greatest resistance possible to the water in its tendency to turn the dam rountl, provided the materials of which it is made 

 were lijhter than water in the proportion of 44 to 100. But the materials are probably more than twice as heavy as water, and the 

 form of o flat a dike is taken, in all likelihood, in order to guard against a more imminent danger that of the dam being 

 carried away by being nhored forwards. We cannot calculate what the proportions are which give the greatest possible resistance to 

 this tendcnry, without knowing tlie tenacity of the materials, as well as their specific gravity. It may very probably be found tUat 

 UK) construction is such as to secure the most completely, against the two pressures at the same time. ^ 



