346 SCIENTIFIC ILLUSTRATIONS [Tern 



The Variable Temperament. 



Physiologists classify temperaments in a way which does not 

 perhaps fully recognise the variable temperament. But the fact 

 is that there is such a temperament, and its peculiar charac- 

 teristic is just this, that it has the power of changing from time 

 to time into the moods of all the other temperaments, from the 

 lethargic to the sanguine. That broad, oval-shaped beetle, the 

 Cassida aurichalcea, so named by Fabricius on account of the 

 brilliant brassy or golden lustre which, notwithstanding its black 

 body, it assumes, is found during most of the summer months 

 on the leaves of the bitter-sweet (Solanum dulcamara), on 

 various kinds of convolvulus, and the sweet potato vine. It 

 has the power of changing its hues, at one time appearing only 

 of a dull yellow colour, and at other times shining with the 

 splendour of polished brass or gold, tinged sometimes also with 

 the variable tints of pearl. And it seems not an inapt illustra- 

 tion of the moods of the variable temperament. IN. 



Inaccessibility to Temptation. 



When the lotus-leaf is placed under water, it reflects light 

 like a mirror, so that the image of any object, if presented to it 

 at a proper angle, is seen by the spectator as distinctly as if the 

 surface were one of polished metal. When water is thrown on 

 the surface of a floating leaf, it flows off like a pool of quicksilver, 

 reflecting light from the whole of its lower surface. This holds 

 good on all occasions. On examining carefully the cause of this 

 natural phenomenon, it is found that the lotus-leaf is covered by 

 short microscopic papillae, which entangle the air, and establish 

 a kind of air-plate over the entire surface of the leaf, with which 

 in reality the water never comes in contact. This peculiarity is 

 familiar to the natives of Australia, who have founded on it 

 a kind of proverb, which may be thus translated : " The good 

 and virtuous man is not enslaved by passion nor polluted 

 by vice ; for though he may be immersed in the waters of 

 temptation, yet, like the lotus-leaf, he will rise uninjured by 

 them." He is surrounded by an atmosphere of purity which 



