346 COSMOS. 



obtenebraret."* The word stella is used here for a celestial 

 constellation, and the narrators may not have explained 

 themselves very distinctly in reference to a caligo which 

 obscured their sight. Father Joseph Acosta, of Medina del 

 Campo, gives a more satisfactory account of the Black Specks 

 and the cause of this phenomenon. He compares them, in 

 his Historia Natural de las Indias (lib. i. cap. 2), to the 

 darkened portion of the Moon's disc in respect to colour and 

 form. " As the Milky Way," he says, " is more brilliant 

 because it is composed of denser celestial matter, and hence 

 gives forth more light; so likewise the Black Specks, which are 

 not visible in Europe, are entirely devoid of light, because 

 they constitute a portion of the heavens which is barren, 

 i. e. composed of very attenuated and transparent matter." 

 The error of a distinguished astronomer in supposing that this 

 description referred to the spots of the Sun, 9 * seems scarcely 

 less singular than that the missionary Richaud (1689) should 

 have mistaken Acosta's " manchas negras" for the luminous 

 Magellanic Clouds. 93 



Richaud, moreover, like the earliest pilots, speaks of the 

 Coal-sacks in the plural, mentioning two, of which the large 

 one was situated in -the constellation of the Cross and another 



* " I asked some mariners who had accompanied Vicen- 

 tius Agnes Pinzo (1499), whether they saw the antarctic 

 pole ; and they told me that they did not observe any star 

 like our North Star, which may be seen about the arctic pole, 

 but that they noticed stars in another form, having the 

 appearance of a dense and dark vapour rising from the 

 horizon, which almost obscured their vision. 



83 Cosmos, vol. ii. pp. 665 and note. 



** Mem. de I Acad. des Sciences dep. 1666 jusqii'd 1690, 

 t. vii. parlie 2 (Paris, 1729), p. 206. 



