64 Remarks upon Bleaching. 



by the Spanish Mathematicians while triangulating the An- 

 des. It has also been seen by some Aeronauts of late years. 

 I do not remember to have seen the Zodiacal light in high 

 latitudes, but I think that Parry states that he saw something 

 of the kind at Melville Island, in the point of the heavens op- 

 posite to the sun, before he reappeared above the horizon, in 

 the spring. 



While on optical phenomena, I must mention the follow- 

 ing as noted in my journal in the Pacific. 



" Ship Jupiter, July 13th, 1824, Lat. 14° North, Lon. 139° 

 W. This afternoon I was gratified with a most beautiful and 

 unusual sight, viz. part of four distinct concentric rainbows, 

 all united to each other. The principal or outer bow made 

 the usual angle with the sun, and was the broadest ; the 

 others diminished in size and brightness, but the prismatic 

 colors were distinctly seen in each, and were all in the same 

 order. The secondary bow, often seen at a distance from 

 the primary, with colors reversed, was not seen. The bow 

 was complete to the horizon, but the compound part was not 

 above 20° in length. The compound part did not appear to 

 be broader than that which was single. The sun was about 

 12° above the western horizon, shining through the interstices 

 of a very dense broken cloud ; each aperture appeared almost 

 as bright as a sun,* and which I supposed produced the dif- 

 ferent bows. The wind was from the direction of the bows, 

 and in a few minutes afterwards a shower of very fine rain 

 fell, and the bows disappeared." 



P. S. General Humphreys told me that on a morning of 

 a 4th of July, in Connecticut, about sunrising, he saw to the 

 westward, and opposite to the sun, beams of light radiating 

 from a point, and those who had never seen or heard of such 

 a thing before, considered its appearance on that day as 

 ominous. This was no doubt the Zodiacal light. 



Art. VIII. — Remarks upon Bleaching. 



Communicated for this Journal. 



The improvements made in the art of Bleaching during 

 the last half century, have in some measure conquered the 



* Those I think must be the mock suns mentioned in the books, — I have never 

 seen any other. 



