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Show EMIGRANT'S GUIDE. is frozen annually, from November to February; the south and south·west winds that warm the air in the vicinity of Lake Erie, become rare at Lake St. Clair. No other fruits can he brought to maturity except apples and winter pears. At Michillimakinac, two and a half degrees farther north, 45° 30' N. lat., observations made in 1707, under the direction of General Wilkinson,.~ si¥>W, that from August 4th to September 4th, the thermometer, m several places beyond Lake St. Clair, never was higher at noon than 70°, anJ that in the morning and evening it often sunk to 46°; which m'akes a colder atmosphere than at .Montreal in the same par~llel. Those. fa~ts ~ully a~cord. w.it~ the general result published by 1\fackenzre, m hrs rel atwn of his mteresting voyages to the west and northwest of North America. I had the pleasure to be made acquain~ ed with this ~stimable ~rave1ler during my residence in PhilatJelpbta, and to receive from h1m much useful information on the subj er~ of my researc~1es. One of bjs companions, Mr. Shaw, also, had <~rnved from a tl11_rteen yec s' residence in the most remote posts of tl e f~r trade. Th1s gentlem ~ n had also the goeduess to reply to my questwns ; and the result oi tb .! ir united information establishes the fol lowing facts : That in a?vancing west of Lake Superior to the Stony or Chippew a~~ moun tams, s f£tr as 72° N. lat., prevails a climate which in seYenty can only be compared to that of Siberia. That the surface of 1 th~ earth i. generally flat aml naked of tirnber, or if any trees do eXISt, they are rare ~n? s.tuTlted. The country is covered with lakes, ~wamps , and a prodtgJ~us number of interlocking water courses, and mcessanll,y s 1 we 1 pt by vtolent and frozen winds, from the north, and, more partJCll ar Y, north\Y st. Above 46° N. lat., the earth is frozen throughou t the year. At several statiom of the fur trade between 50° anu 56° N. I.at., wells, though very necessary, cannot' be sunk; that Mr •. Shaw h ~rmelf rna le the attempt at .St Augustine, six leagues from til€ moun tams, and though the attempt was made in July, the Ia~ botuers found th~ earth thawed three feet; but below that depth frozen, and becommg mor~ solid in descending, tbey were constrained' to abanuon the undertak rng twenty feet beneath the surface. .~he correctness of the'se facts cannot be doubted from the respectabdtty of the witnesses, and from the credible support received fro.m other testimony. Robson, an En<.rlish engineer who in 1745, bUiltFortWale·s oni?:..r' Ju. s' on'sB . n y, 59oN. l at., recoun't s, wi·t'h surpm· e and candour, that w1shmg to smk a well in tbe month of September, he f~und the ground thawed three feet, by the recent heat of sum~ er' but ~fider that superstratum of earth Jay another of eight Inches deen, frozen as firm as a rock. The;1 commenceu a stratum obf dry loo:'sh~ fro.·z eft san d , m· w lH ·e 11 the workmen coulu finu no water, ecause the mmsture near the surface was rendered solid icc and pr~vented the water from penetrating belcw the superficial b~d of eaith thawed by the recent summer heat } :1. ~ Uw ar d U mf rev1· 1 le, an agent of the H, udson Bay Company, from ·Medical Repository of New-York1 Vol. I. page 530. EMIGRANT'S GUIDE. 243 J 77 J until 1782, a sensible and correct observer, attests, that the earth in these regions even in the heat of summer, when ·the heats are for a term of four or five weeks very intense, does not become thawed more than four English feet in depth, where the Jand is cleared of timber, and not more than two where the surface is shaded by dwarf juniper and pine trees, the only timber in the country. It is from all these facts made evident, that beyonc} a certain lati· tude, the climate of the interior of North ~merica is not less cold than on parallel latitudes upon the Atlantic co:fst. 'rhe mean term of the chang~ is about 45° or 4G0 N. lat., assuming, as a natural limit, the Canadian lakes, but more particularly the Algonquin mountains, con~ fining the warm climate of the west to nine or ten degrees of latitude, and also encircled on three sides by other mountains. No doubt but t~at the presence of these mountains contribute in part to produce the difference found to exist between the climates north and south of their summits: But what is the primary cau_e? From whence proceeds this really sjngular geographical phenomenon ? Behold the problem solved! a comparison of many facts and circumstances, have led me to consider as the principal agent, a generally prevailing current of air in the basin of the Mississjppi; which current differs from those of the coast of the Atlantic ocean. I think myself able to furnish to my readers the means of forming their judgment, by develop· ing the entire system of the various current.s of air annually prevail-ing in the United States. . Mr. Volney then enters into an investigation of the courses, and causes of the winds of the United States, commenced with the expression, " that in Europe, particularly in France and Enaland, the inhabitants complain of the inconstancy of the winds, and of the sud· ?en and violent changes produced in the atmosphere through their mfluence; but that the variations in the air in Europe, were nothing when compared with those in the United States." Data have never yet been collected to establish the degree of correct comparison between the climate of western Europe and that of any part of America. An observation is in the mouth of nearly all ~en who speak .on the subject, coinciding with Mr. Volney, that the mconstancy and contrasts of atmospheric air are much greater in ~merica than in £urope ; but a perusal of several artic les in RoZier's Agricultural Dictionary, would serve to render this assertion at least doubtful.~ That the difference has been exagaerated to at le?st ten times its quantum, we have no doubt. A real differ~nce in climate does exist, between western Europe and eastern America, of about ten degrees of latit1.Idc ; but the corresponuing climates exh ibit very nearly similar phenomena. The south of France and tbe ~outhern parts of the United States possess a remarkable coiucidence m the aspect of their respective local positions, as also in the general ~haracter and daily temperature and change of their climates. t Disquisitions Ot:l the winds of any country are an idle speculation, if not founded upon a very detailed knowleJge of the ranges of moun- * See page 30 of this Treatise. .. .. Sie page 167 of this 'freatisc1 note. • lJ,, |