In these several processes of taking the latitude there are numerous possibilities of inexactness. It does not appear that any correction was made for refraction of light, or the precession of the equinoxes. But the most important source of inaccuracy was in the use of the astrolabe whose disk was so small that its divisions could not be carried beyond degrees, and consequently minutes were arrived at by sheer estimation, and usually when the work was completed, the error was not less than one fourth or one half of a degree, and it was often much more. This accounts fully for the inaccuracies of Champlain's latitudes from first to last throughout his entire explorations, as tested by the very exact instruments and tables now in use. No better method of determining the latitude existed at that day, and consequently the historian is warned not to rely upon the latitude alone as given by the early navigators and explorers in identifying the exact localities which they visited. 63. Subsequently called Hurons. 64. _Vide_ Vol. I. p. 49; Vol. II. note 219. CHAPTER IV. CONTINUATION.--ARRIVAL AT THE ABODE OF TESSOUAT, AND HIS FAVORABLE RECEPTION OF ME.--CHARACTER OF THEIR CEMETERIES--THE SAVAGES PROMISE ME FOUR CANOES FOR CONTINUING MY JOURNEY, WHICH THEY HOWEVER SHORTLY AFTER REFUSE.--ADDRESS OF THE SAVAGES TO DISSUADE ME FROM MY UNDERTAKING, IN WHICH THEY REPRESENT ITS DIFFICULTIES--MY REPLY TO THESE OBJECTIONS.-- TESSOUAT ACCUSES MY GUIDE OF LYING, AND OF NOT HAVING BEEN WHERE HE SAID HE HAD.--THE LATTER MAINTAINS HIS VERACITY--I URGE THEM TO GIVE ME CANOES.-- SEVERAL REFUSALS.--MY GUIDE CONVICTED OF FALSEHOOD, AND HIS CONFESSION. Nibachis had two canoes fitted out, to conduct me to another chief, named Tessoueat, [65] who lived eight leagues from him, on the border of a great lake, through which flows the river which we had left, and which extends northward. Accordingly we crossed the lake in a west-northwesterly direction, a distance of nearly seven leagues. Landing there, we went a league towards the northeast through a very fine country, where are small beaten paths, along which one can go easily. Thus we arrived on the shore of the lake, [66] where the dwelling of Tessoueat was. He was accompanied by a neighboring chieftain, and was greatly amazed to see me, saying that he thought I was a dream, and that he did not believe his eyes. Thence we crossed on to an island, [67] where their cabins are, which are poorly constructed out of the bark of trees. The island is covered with oaks, pines, and elms, and is not subject to inundations, like the other islands in the lake.