GREEN SUNS AND RED SUNSETS. 605 



there seems little reason to doubt that the monsoon had carried the 

 volcanic dust along with it, the dust obscuring the sun. The dis- 

 tance is nearly three thousand miles." 



Dr. Budde, of Constantinople, was assured, when traveling in 

 Southern Algeria in 1880, that the sun has a decidedly blue color when 

 seen through the fine dust of a Sahara wind. Mr. Edward Wbymper, 

 remarking upon a metallic-green coloration of the moon, observed on 

 some evenings in December, says that the peculiar hue recalled to him 

 a similar appearance which he had witnessed in South America when 

 the atmosphere was charged with volcanic dust ; and he has described 

 the colorings seen by his party under a cloud of ashes from Cotopaxi 

 in language which would almost precisely apply to the diversified ap- 

 pearances that are the immediate subject of our discussion. Extremely 

 brilliant colorations of the sky have been mentioned by several travel- 

 ers as common spectacles in a particular tropical belt. Colonel Stuart 

 Wortley, who spent the year 1862 in Southern Italy, in the study, by 

 the aid of photography, of the formation of clouds, was struck with the 

 unusual colors of the sunsets during and after the eruptions of Vesu- 

 vius with which that year was distinguished. Four years ago, while 

 sailing in the Pacific, he was much impressed with the fact that " very 

 frequently the whole vault of heaven was overspread with magnificent 

 and glorious coloring, and that in the higher regions of the air colors 

 were found that were never seen in the horizon or below a certain 

 height." Inasmuch as this exceptional magnificence and peculiarity 

 of coloring only occurs in certain latitudes and in well-defined belts, 

 he suggests that, seen in the new light that is now cast on the sub- 

 ject, *' the constant stream of volcanic matter thrown out by the great 

 volcanoes in the mountain-ranges of South America, and possibly from 

 elsewhere, form an almost permanent stratum of floating matter, car- 

 ried in certain directions and kept in certain positions by alternating 

 currents in the higher regions of the air, and that to this stratum of 

 volcanic matter much of the exceptional coloring, found to be asso- 

 ciated with sunrises and sunsets in portions of the Southern Pacific 

 Ocean, is due." As an interesting coincidence in connection with this 

 view may be noticed the extraordinary fact, to which Mr. Lockyer has 

 called attention, that "before even the lower currents had time to 

 carry the volcanic products to a region so near as India, an upper cur- 

 rent from the east had taken them in a straight line via the Sey- 

 chelles, Cape Coast Castle, Trinidad, and Panama, to Honolulu, in 

 fact very nearly back again to the Straits of Sunda." 



Very strong evidence in favor of the theory of the agency of vol- 

 canic dust has been derived from the examination of the sediment in 

 freshly fallen snow at Madrid, Spain, on the 7th of December, and of 

 the mineral matter deposited by a rain that fell at Wageningen, Hol- 

 land, on the 13th of December. The sediment at Madrid, besides the 

 ordinary atmospheric dust of the city, contained particles of what ap- 



