NOTES 323 



cloud consists of separate rain-drops, and he maintains that even 

 if it did they would not unite to give one unbroken image. In 

 proof of his contention he urges the fallacious assertion that if a 

 number of mirrors are joined together and a man is placed before 

 them, each gives its own reflection, and thus a single man becomes 

 multiplied into a crowd. If he had ever tried the experiment or 

 had visited the shop of a mender of mirrors, he would have seen 

 that the separate pieces, if strictly arranged on the same plane, 

 reflect a single image. His imaginary antagonist asks for an 

 explanation of the rainbow-like colours displayed by the spray 

 from a burst water-pipe, or the splash from an oar, which are, of 

 course, cases strictly parallel to the falling shower of rain (24). 

 The resemblance is at once granted, but is explained away on 

 the ground that the drops fall so quickly that they cannot form 

 reflections of the sun, and that to produce such reflections the 

 medium must be at rest. The objector once more strikes in 

 with a reference to the rainbow colours to be seen in a glass rod 

 which is placed obliquely in the path of the sun's rays (30). 

 These prismatic tints, as has long been known, are due to the same 

 decomposition of white light, as in the rainbow. But Seneca 

 claims the illustration as furnishing additional arguments in his 

 favour. He maintains that no colour is really produced in the 

 rod, but only a false appearance of colour, his idea being appar- 

 ently that unless the colour is inherent in an object apart from 

 direct sunlight, it is only apparent and not real. The glass, he 

 says, tries to reproduce the sun's image, but fails because of its 

 unsymmetrical form, the reflections being crowded together and 

 confused into the appearance of a single band of colour. In 

 regard to the falling drops of rain in a shower he contends that 

 they receive the colour but not the image of the sun, and he is 

 led away by the false analogy of the varying tints of a peacock's 

 neck as the bird tosses its head (25). At one part of the dis- 

 cussion he affirms that the colours of the rainbow come partly 

 from the sun and partly from the moist cloud (21). Further on, 

 however, he agrees that they proceed from the sun, but are only 

 apparent, for if another cloud comes across the face of the 

 luminary they at once vanish (29). The greater diameter of the 

 rainbow compared with that of the sun as seen by us he accounts 

 for by the analogy of a concave mirror, which greatly enlarges 

 the objects reflected from it. At the conclusion of the discussion 

 he repeats his belief that the rainbow and the corona or halo 

 have no definite material inherent in them, but are like a mirror 

 which reveals only a deception, the mere phantoms and empty 

 imitations of real bodies, which certainly do not exist in the 

 mirror, and therefore cannot come out of it (41). 



