Isothermals Of The Lake Region

3!c 4?Xicítgau %x$xs Professor Winchell read n paper beforo tbo Associntion of Mocleru Scionco at Troy last eek. Tlio puper embodied the resalta oTcareful and proiouged observation at variona localitiea n the jt of the great Likes as far as . Tlie Professor used in tlie flbtïtration of t!' subject niric isotherraal charta for ssveral ot tbo summer raonthg, and winter, aututno and pprin yeta mean minima and extrema minima. The Professor indicated tho wonderful changos n toinpcraturo 'caused by tbo great lotes in tho bóntiguoúa country. Thn coolinsx iiilluenue, geienen attesti, a oxerled chielly on thewest sido of Lnke Michigan and the warm on the east ; whicli depend i ngaiu upan the prevailing vrind ■ in summer along lbo sbores of tbo Iako from the eapt of the tneridian in sinnmcr, and west of it in winter. In July, for example, tbo eooling influptice on Lake Miohigafl dcflcots the isothermala 110 miles, whilo to the west of the lako tliey aro doflected 400 miles. In Jnnuary, tbo mean ternporuturc on tbe eaet side of the lake is fmm four to sis dogrees hjgher than on the west side. Tlio isothermnls for spring show a mark ed cooling influence exerted on the west Fide, and thoso for lbo autumn a warmiug iiiflnenee on the esiet side, tbo joint effect of whieb is to ronder tb a growing eeason six to thiiteen days longer on the east side than on the west side of tbe lake. The moet niarkod effect and the most surprising is feit in times of extreme iveather, especially if cold. The iaotberin;il of meao and extreme minima run almost literally ndrth and south along the shoro.of Lake Mioaigan. ïhe most eicessive cold at Mackinac for a period of twenty-eight years is not on the average pivatur than at Fort Riley, in Kansa, 480 miles furtber soutb. At Chicago it wns oue degreo less for eleven years. The iotberniüls of Ihe yeur niight be expected to ebow no resultunt of lake influences. Ou tho contrary, it demoustrat03 wonderfully the waverincr influences excited on the east side; this becauso the liquid tempe.-aturo is abore tbnt of the contiguous land. Sercral causes ceount for tbe increased heat of the water. ïhe great diptli of the lake (!J00 feet) is suffieient to secure 18 degrees of iucieaf ed tempernturo from the eartb's heated interior. Tbis, (lill'nsiid through tho waters of tbe lake, would result in nn equaj and average elevation of temperature sufficient to cause t!ie pheuomcua witnessed in tbe teniperature.