The lights made to revolve by means of clockwork, were fed with mineral oil, a refined kerosine; and the refraction was caused by highly polished 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.
The wind continued to lash the fierce billows during the day until evening; so we decided to remain in Tawas City until the dawn of the next morning.
Guided by the pale light of another aurora, we resumed our voyage, finding the surface of Lake Huron still in uproar.
During this forenoon, we had occasion to witness a prospect quite novel to us. Glancing to our left, on Michigan's sylvan shore, we saw the bickering flames of a ravaging forest fire; dyeing all the surrounding air and landscape crimson, while dense clouds of smoke hung over the burning land like a pall upon which the sun-rays were reflected with weird effect. It was, indeed, an unusual sight, exhibiting strange beauty and splendor.
In a short time we experienced the disagreeable consequences of this conflagration in the woodlands, caused by the extreme dryness prevailing in these regions for several weeks. For, as we reached Alpena in Michigan, at about noonday, we found the atmosphere completely saturated with smoke, and intermixed with particles of burnt material.