228 nature's teachings. 



tlieir dwellings. Now, as these wonderful buildings are nearly 

 as hard as brick, and, indeed, are composed of the same materials, 

 it is necessary that the claws of the Ant-bear should be modified 

 so as to be able to break through the walls. Accordingly, 

 they are much more curved than those of the Mole and the 

 Mole-cricket, and so serve for tearing as well as digging, being 

 struck into the wall, and thus pulling it down, just as a 

 labourer breaks down a bank with his mattock. 



Indeed, had we wished to extend these analogies still further, 

 we might easily have given the claws of the Aard-vark as a 

 prototype of our English mattock. The same weapons as 

 possessed by the Ant-bear of tropical America are used in 

 exactly the same manner, but are even stronger, and extend to 

 such a length that when the animal walks, it cannot stretch its 

 claws out in front, but is obliged to double them under its feet. 



Shears and Scissors. 



These instruments are sure signs of civilisation, no savage 

 nations having the least idea of them. Even the Kafir and Esqui- 

 maux tribes, which are such admirable workers in skin, never 

 use scissors in shaping their garments, but invariably employ 

 knives for that purpose. The Chinese, however, seem to have 

 known scissors from time immemorial, and to have shaped them 

 almost exactly like our own instruments. I possess one pair 

 of tailor's shears from China in which there is only one ring, 

 namely, that for the thumb. The place of the other ring is 

 taken by an elongated, slightly curved and moderately pointed 

 rod of steel, which is used for tracing the pattern on the material 

 preparatory to cutting it. 



Simple as the scissors may seem, they combine several very 

 important principles, namely, the inclined plane, the lever, and 

 the cutting edge. "Were they to be merely two edges moving 

 directly upon each other, their effect would be comparatively 

 slight ; but, owing to the manner in which the blades are fixed 

 at one end, they are drawn as it were over the object between 

 them, and so divide it with comparative ease. In some instru- 

 ments, such as the pruning scissors, there is only one cutting 

 blade, the other being used merely as a support for the branch 

 which is being cut. 



