The little party turned northward on the 17th of July, just one month after having entered the river, and the tiresome ascent was begun. Reaching the mouth of the Illinois river, the latitude of which is given as 38 degrees, they entered that stream, ascended it, passed the portage between the Desplaines and the Chicago rivers and launched their canoes upon Lake Michigan. Late in September they reached the Jesuit Mission of St. Francois Xavier, situated near the head of Green Bay. They had left this mission four months previously and had traveled in the meantime upwards of three thousand miles. Marquette's narrative, just cited, is so vague with reference to topographical details and so inconsistent with respect to geographical positions that little dependence can be placed upon it, except when taken in connection with the accompanying map. This last will be made the subject of somewhat careful examination, its genuineness being assumed as thoroughly established. We have to note in the first instance that the latitudes as given upon Marquette's map are in error, all being about one degree too far south, except Akansea, the southernmost point reached, which is correctly placed at 33° 40'. Herewith is presented a carefully prepared copy (See Fig. 1) of a portion of Dr. Shea's fac simile of the original, much reduced. The parallels of latitude are as indicated by the marginal figures in the original, while the meridians of longitude are separated by intervals obtained by multiplying the average latitude interval of one degree by the cosine of 40 degrees, the "middle latitude"-in accordance with a well known mathematical principle. The meridian of 91 degrees has been placed near to the mouth of the Wisconsin, its true position. On the right hand margin of the map Marquette's latitudes are indicated. On the left these latitudes have been increased by one degree; so that, if read from this margin, Marquette's map has been lifted bodily one degree in latitude. The dotted sketch on the left of the map represents the true course of the Mississippi and, presumably, those tributaries which are noted by Marquette. The longitudes along the lower margin, to the left, refer to this dotted sketch only. A comparison of Marquette's river with the true course of the Mississippi shows that his plot is a marvelously accurate one, as far down as the mouth of the Ohio. Inasmuch as means of determining longitude by portable instruments were not available in Marquette's day, we can only explain the accuracy with which his longitudes are plotted by supposing that careful note was taken, at least until the latter part of the voyage down stream, of distances and courses sailed. Otherwise, it is impossible to explain the close conformity exhibited by the accompanying illustration. This discrepancy of one degree in Marquette's latitudes would seem to demand explanation. Let it be noted that the complete map includes a large portion of Lake Superior, St. Mary's river and the straits of Mackinac, regions well known to Marquette and the other Jesuit missionaries of the time. Accompanying the Jesuit Relation of 1670-1, prepared by Dablon, is a map of this upper lake region entitled, Lac Supérieur et autres lieux où sont les Missions des Pères de la Compagnie de Jésus comprises sous le nom d'Outaouacs. Without doubt Marquette was familiar with FIG. 1. Marquette's Map, copied from the fac simile of the original published in Shea's Discovery of the Mississippi, 1853. The upper portion of the map, including a large part of Lake Superior, is omitted. The latitudes on the right hand margin are those of Marquette. The dotted sketch on the left represents the true course of the Mississippi, the corresponding latitudes and longitudes being given along the left hand and the lower margin respectively. To Marquette's plot of the river the suggested extension to the south is added to indicate the way in which the plot might have been completed but for the correct determination of latitude made at Akansea. this map, which was probably the work of some of his own associates. It is even conceivable that he sketched the upper portion of his own map directly from it. The fact that it includes, among others, the altogether irrelevant entry, Chemin au Assinipoualak à 120 lieus vers le Nordouest, which also appears upon the map of 1670-1, seems to confirm this theory. Now upon this map of 1670-1 the latitudes of Mission du St. Esprit, of Mission de Ste. Marie, of St. Ignace and of the Pottawattomie village at the head of Green Bay, near to the Mission of St. Francois Xavier, are exactly as recorded upon Marquette's map. Whether the mistake is due to the defective astrolabe of some Jesuit geographer, or to some other cause, does not concern us. The error is evidently reproduced in the upper portions of Marquette's map and, supposing that his map was plotted by "dead reckoning," would naturally be propagated far down the Mississippi. Certain it is that the latitudes upon the map do not agree with those given in the narrative. Moreover, those paragraphs describing the voyage from the time at which the explorers entered the Mississippi up to the time of landing near Peouarea are utterly irreconcilable, so far as the latitudes and directions are concerned, with the true course of the Mississippi. Neither is it possible to interpret them at all satisfactorily upon the assumption that some of the latitudes were correctly given by Joliet while others are of Marquette's own determination. While the journal does not specifically state that the latitude vaguely given as "40 degrees and some minutes" is that of Peouarea, it is evident from the map that this is to |