THE AMERICAN JOURNAL OF SCIENCE AND ARTS. [SECOND SERIES.] ART. I.-Notes and Remarks connected with Meteorology on Lake Superior, and on the variations in its level by barometric causes, and variations in the season; by Wм. W. Mather, Professor of Natural Science in Ohio University. THE author of this paper has spent three summers and parts of the autumns, on Lake Superior, exploring the coasts, and examining mines in operation besides undeveloped veins of ore. Some meteorological observations were at the same time made, that may not be unacceptable to the scientific public. During June and a part of the month of July, the weather is generally serene, with a clear sky, and little rain except occasional thunder-showers. The lake is calm, and this is the most favorable season of the year for coasting in boats and canoes. The prevalent winds during the summer are from the west and s.w. Many parts of the lake even in this calm season of the year, are subject to sudden squalls. The Indians and voyageurs are very cautious; but many persons unacquainted with the coast and the local land blasts, frequently expose themselves to great peril. These land blasts are often violent when nothing is seen to indicate their approach. Some of the voyageurs state that while coasting along with the weather calm or only a gentle breeze, the boat, just before one of these blasts, seems to be suddenly lifted as if struck by some unseen force; and in such cases they at once make a landing. Boats strongly manned cannot always make headway against these sudden squalls, and frequently they are driven off the land. There are some localities where these blasts are frequent. At Sand Bay, as it is called-a mere indentation or bight of the coast SECOND SERIES, Vol. VI, No. 16.-July, 1848. 1 between Eagle Harbor and Eagle River, four or five miles across at its capes-puffs and blasts of warm air from the land are common, especially in the afternoon and evening. The land rises very gradually from the coast for one half to one mile, and then rapidly ascends to the height of the mountain eight hundred to twelve hundred feet, and this range of hills extends for many miles with nearly uniform surface and height, rarely broken by ravines. The wind often blows strongly from the land for many hours. The same facts have been observed at Porter's Island and at Copper Harbor; both open to the north on the lake, and both have similar ranges of high land on the south. At Bete Gris Bay on the southern side of Kewena Peninsula, a range of mountains eight hundred to thirteen hundred feet high, bounds the north shore of the bay and extends many miles to the west, gradually curving around to the w.s.w. and s.w.; and a flat country skirts the bay on the south and west, and extends thirty or forty miles to the s.w. between the mountains and the south coast of the peninsula, with a breadth of four to eight miles. Violent blasts of warm air often blow from the west out of this bay in the afternoon. The bay opens to the s.E. In Yellow Dog Bay at the mouth of Yellow Dog River, similar facts have been observed. This bay opens to the N.E. While it was calm at the capes of the bay and on the lake, a strong blast of warm air from the land blew from the s.w. out of the middle of the bay; and between this axis and the capes, the air blew in towards the axis, converging towards a point outside the bay in the lake. Such facts are common in calm weather when the sun shines brightly. Similar observations have been made in many places, and they are here noticed because they seem to be in opposition to the generally received notions of the action of the sun and heated air in a hilly and mountainous region. These phenomena often extend into and through the night. The theory of the land breeze explains it for the night, but not for the day. Notes in regard to the weather and barometric waves on Lake Superior, 1846. The following memoranda from my diary, are introduced with a view not only to shew the general character of the weather on the lake coast, but also to shew some of the facts from which the inference is drawn that the sudden fluctuations of level of the water on the lake coast, generally precede gusts or storms. The aurora borealis has long been considered a precursor of gales. In the meteorological register annexed, some observations of greater exactness are registered bearing on these points. June 9. On Lake Superior, between White Fish Point and Manito Island; calm, occasionally a light s.w. wind; fog banks at a distance through the day, appearing like distant land. 10 to 15. Pleasant weather; nothing noted in diary. 15. Rain last night and cloudy morning; wind east by north; cleared off at 10 A.M. 16 to 25. Pleasant weather; nothing noted in diary. 25. Wet stormy morning and fog till 11 A.M. at Salmon Trout River; cleared at 12; calm. 26 to July 1. Pleasant hot weather; in Ontonagon region. July 1. Pleasant hot weather; on the west branch of the Ontonagon. 2. Thunder in morning, and succession of heavy thunder showers all day; twenty miles south of Lake Superior, on the west branch of the Ontonagon. 3 to 9. Pleasant weather and very warm; exploring as above, and returning to the mouth of the Ontonagon, and coasting to Iron River. 9. Wind strong from the west until 3 P.M.; then calm and very warm; heavy thunder shower and very vivid lightning in the evening, in the direction of Thunder Cape, north, and Thunder Bay, where almost every evening after a pleasant calm day in summer, a thunder cloud may be observed. 10. Calm in the morning; coasting west till 9 A.M., when the heavy west wind obliged us to land; calm at evening. 11. Surf heavy on shore from a blow in the N.w. last night, when there was a heavy thunder gust. Pleasant day; wind eastward till 3 P.M., when it came around to the west. 12. At Iron River, pleasant day; wind in the morning strong from the east. 13. Strong current set into the river this morning early. Heavy wind at sea from the west at 5 A.M. Embarked with boat sail reefed, carried away main sheet and broke rudder. Wind hauled from the west at 64 A.M. to N.E. blowing a gale, but we were enabled with great difficulty, and danger of swamping on the bar of the Ontonagon, to enter that harbor. After 10, cleared off hot and sultry; cold evening and had a fire before my tent door at Mendenhalls mines; musquetoes in myriads. 14. Pleasant, calm day, except the land blasts which were observed on the Ontonagon River as hot blasts of air, now from one point and then from another. Calm, except occasional hot puffs and blasts from the shore of the lake when off the re-enterings of the coast; went to Misery River. 15. Calm and pleasant, except warm puffs of air off shore as yesterday. 16. Same as yesterday, except that on arriving within a few miles of Copper Harbor where the woods were extensively on fire, momentary hot blasts of air were often felt, and the air was so thick with smoke that rocks could not be seen at three times the boat's length. In the evening and day, there was a steady heavy blast from the land, and large flakes of fire from the burning forest were carried entirely across Lake Fanny Hooe, so that it was with great difficulty the buildings at Fort Wilkins, half a mile off, could be preserved from the fire. 17 to 28. At Presque Isle, eighty miles south by east of Kewena Point. A rise and fall of the waters of the lake were observed in the bay, and the captain of the Schooner Swallow consequently looked for a blow, though the weather was pleasant and calm, excepting a slight off shore breeze. The vessel sailed at 4 P.M., but in the night a severe blow came from the north and lasted two days, and the vessel with difficulty was kept off the shore. 28, 29. Rainy part of the day, but without heavy wind at Presque Isle; the wind was from the south. A heavy gale and severe rain set in in the night from N.E., and continued till next (30th) morning, when the waves were from fifteen to twenty feet in perpendicular height. There 31 to Aug. 7. Weather pleasant but very warm, except on the lake shore, where the cold waters temper the heat. was little wind, except warm puffs and blasts from the shore during the middle and latter parts of the day, off the reëntering of the coast. During these days I was coasting between Presque Isle and Huron River, encamped on the shore, or exploring in the interior from five to ten miles from the coast. On the evening of the 6th, at the mouth of Huron River, the water flowed rapidly into the mouth of the river for fifteen minutes, and was raised twelve to sixteen inches above the usual level, after which it flowed out until it reached the usual level. Aug. 7. Similar variations in the level of the lake and river, were observed in the morning. Severe thunder-showers from N.w. succeeded, with very strong winds, uprooting trees. 8. Heavy thunder-gusts and showers through the night, and forenoon of to-day. 9. Pleasant day; wind east at six in the afternoon; another rise in the water of the lake of eighteen inches, and a sudden fall again in fifteen or twenty minutes, about 1 P.M. Heavy thundergust and some rain at 4 P.M. Strong N.w. wind (7 to 9) all night, with some rain. Trees uprooted by the gale. 10. Pleasant day; wind strong from east in afternoon; calm in evening. 11. Pleasant day; calm till 8 A.M; wind south out of Huron Bay at 8; N.w. 5, at Point Abbaye, 9 to 10 A.M.; calm at 10; south on the side of Kewena Bay at 10 A.M., and s.w. 4, near Traverse Island. Sailed from the middle of Kewenaw Bay, with this wind constantly increasing in force till evening, when I reached Bete Gris Bay, and landed with difficulty through the surf, although the wind there blew off shore, and the waves came in to the bottom of the bay at an angle of about 110°, different from the direction in which they rolled outside the bay. 12. Rained hard in the night, with strong wind from the east, and this morning from east and s.E., and thence hauled to N.N.W., and finally in the afternoon to s.w. Started this afternoon to go west from Bete Gris Bay to the west end of Lac la Belle; but the wind blew so hard from w.s.w., that this little lake of two and a half miles in length was a sheet of foam. A strongly manned boat was at times unable to stem the wind in the outlet, and on going into the lake, was half filled with water by the waves in a few moments, and the excursion was abandoned for that day. At sunset it was calm. 13. Calm in the morning at Bete Gris Bay. At 11 A.M the wind began to blow out from Lac la Belle as yesterday, and increased in violence till 4 P.M., after which it abated gradually. To-day at 3 P.M., a well manned boat could not head the wind and sea in this little sheet of water, and make any progress. At 7 P.M. it was calm. This w.s.w. wind flowing out to the open lake from along the base of the mountains, is very common in the afternoon of warm pleasant days in summer. 14. Loons were very vociferous between 2 A.M. and daylight. This is generally considered by voyageurs as an indication of strong winds, or of approaching storms. I aroused my men before day, and embarked for Copper Harbor. The air was clear and calm till 8 A.M. Wind then from s. 2, towards the land; at 9 A.M., S.S.E. 5, near the southeast point of Kewena Peninsula; at 10 A.M., s. 3, at the east end of that peninsula, with frequent strong blasts off shore from the west, of warm air; 11 A.M. till 2 P.M. on north side of the peninsula, a dead calm, except occasional puffs of warm air from the land; from 2 P.M. the wind blew very strong from the west all night. 15, 16. Stormed all day, wind and sea heavy from the west. 17. Pleasant, but wind and sea heavy from the west. 18. Stormed all day. 19. Stormed till noon, with heavy west wind, then clear and calm. Embarked at 4 P.M. for the Portage, but heavy squall and dense fog from west forced us to land at 4 P.M. Stormed and blew strongly from N.w. all night. 20. Very heavy surf on shore: could not pass the breakers. Calm. Sea calmed down enough to pass the breakers on the deep part of the reef at 1 P.M., but lake still too rough to travel in safety even in a fine whale boat. 21. Pleasant, warm day; little wind, except occasional warm blasts from south, off the land. 22. Wind and sea heavy from west till 12 M., when it hauled suddenly to east. Went from Eagle River to near the Portage. 23 to 26. Pleasant, fine weather; wind not noted. |