Miscellanies. = 989 
The explorations and surveys were made in the boats and vessels, 
frequently running with the vessels within a quarter or half a mile 
of the shore and coral reefs; and I am happy to inform you that not- 
withstanding the dangerous navigation among these islands, we have 
escaped without accident, and I flatter myself that I have carried into 
effect most fully all that part of your instructions referred to in the 
notes of Admiral Krusenstiern, which were attached to and formed a 
part of t..em. 
No opportunity has been omitted to land upon the islands and es- 
tablish a friendly intercourse-with the natives, and to make all possi- 
ble observations and collections in the different departments, all of 
which will be disposed of agreeably to your instructions. 
On my arrival here, I was gratified to find by the observation had 
at point Veners, my chronometers in error only I’ and 3” with the 
longitude of that point. 
I shall remain here only a few days to complete our observations 
and procure a supply of wood, water, fresh provisions, and vegeta- 
bles, for the crew, and proceed to carry out your farther instructions 
with all dispatch. I have the honor to be, Sir, most respectfully, 
our obedient servant, 
Cuartes WiLkes, Commanding Exploring Expedition. 
To the Hon. J. K. Pavupine, Secretary of the Navy. ‘ 
15. The Twilight Bow. 
To the Editors—I have for several years been in the habit of 
observing a daily meteorological phenomenon which occurs twice 
in the 24 hours, and which, so far as I have been able to ascertain, 
has never been noticed in any scientific work, and yet seems worthy 
of the attention of philosophers. I mean the appearance, morning 
and evening, of a prismatic bow. Having shown the bow to several 
friends, they were equally struck with the fact that so obvious, and at 
the same time so beautiful a phenomenon, should not have attracted 
attention. It may still have been noticed in some scientific journals, 
though it has escaped my observation. ; 
The bow in the morning begins to be defined in the west about half 
an hour before sunrise. The height of the arch is about 15° above 
the horizon, and spans nearly, perhaps quite, 180°. Its first aspect 
is that of a blue belt, the red next appears like a faint blush above 
the blue, producing the purple as it mingles with the blue. Then 
appears the yellow above the red, producing the orange as it mingles 
With the red. As the sun advances towards his rising, the bow de- 
scends to coincide with the horizon, and at an angle of $° above the 
horizon, or about 15 minutes before sunrise, the colors are most dis- 
