metallic reflectors.

This visit to the Sand Beach Beacon was quite instructive; since we viewed
there a practical application of an important principle in optics, based
on the reflection of light.

On Wednesday morning, the first beams of the new-born day had just
appeared, when the yacht continued her voyage on Lake Huron. After a
course of nearly twenty-two miles, we approached _Saginaw Bay_--the
largest indentation on the western lake shore--comprising a width of
thirty miles and a length of sixty miles.

The passage across this bay, feared by many experienced navigators on
account of the heavy ground swell, did not give us any cause for anxiety
at first. Gradually, however, the sea became quite rough, and the enraged
waves dashed their spray pearls even upon the deck of our sailing home.

"The soft, wild waves, that rush and leap,
Sing one song from the hoary deep:
The south wind knows its own refrain,
As it speeds the cloud o'er heaven's blue main."

The strong breeze springing up in the forenoon, increased at midday. A
line of low waves, first creeping sinuously into the bay, and tossing
their snowy crests like troops of wild steeds, rolled higher and higher
with the noise of many waters; and to escape the wrath of the angry sea,
we stopped at the harbor of _Tawas City_, located near the northern
extremity of Saginaw Bay. It is a thriving country town, with about 1,000
inhabitants, largely engaged in lumber trade.