24 FACTS FOR MECHANICS. 



any food for several months and on its arrival here, several mice were 

 put into the cage. The new occupants betrayed no alarm at the presence 

 of their ugly companion, but danced about nimbly and raced over his 

 snakeship, who showed no inclination to molest his little murine asso- 

 ciates. The mice would even nibble at his scales, when the serpent 

 would shake them off by a slight contortion, as though he were not fond 

 of being tickled by a mouse. It was only some hours after, that he 

 bounced on one of his little tormentors, stung him with his fangs and 

 swallowed him whole. The other mice now continued to play about 

 and even nibble at his nose with impunity. A large rat was now put in 

 the cage, and he felt disposed to show fight — but the snake turned away. 

 We were waiting the issue a long time, and after the rat was in the cage 

 unharmed for five or six hours, we provoked the snake by moving the 

 cage, which caused the mice and rats to run over him more rapidly. 

 After a long trial to rouse his serpentine ire, he at length, stung the rat, 

 M'ho uttered a faint squeak and died in about eleven minutes. After he 

 Avas smitten, he played about as usual, but his efforts grew fainter until 

 he died. In about half an hour, the snake opened his enormous jaws 

 and made an effort to swallow him, but after repeated trials, he failed. 

 Another large rat was put in and now there was a regular battle. The 

 rat fought valiantly, biting the snake severely in the nose several times^ 

 but at length, by a dexterous turn of the serpent, the poor rat received 

 the fatal wound and perished. J. G. M. 



FACTS FOR MECHANICS. 



To case-harden Iron. 1. It is well known to mechanics, that iron 

 is not capable of being hardened like steel. 



2. It is often important to render the surface of a particular portion 

 of a piece of iron hard, whilst the rest remains soft iron. This is call- 

 ed case-hardening. 



3. The old metliod of pioduring this eflect, which was both troub- 

 lesome and consumed much time, consisted in introducing the article 

 to be case-hardened, together with fragments of old leather, or hoofs, 

 skins, or horns, into a box of sheet-iron, and subjecting the whole to a 

 strong red-heat for an hour or two. During this time the exterior sur- 

 face of the iron absorbs and combines with a portion of the carbon of 

 the animal matter, and is converted into steel, as in the ordinary pro- 

 cess of forming steel. The article of iron thus treated is coated with a 

 case of steel wliicli may be tenipeied or hardened in tlie usual way, and 

 is therefore said to hv case-hardened. 



