The winter passed slowly for Marquette; but at length, on May 17, 1673, the explorer and the missionary with five assistants—a feeble band to risk a plunge into the unknown—launched their canoes and headed westward.

The explorers first shaped their course along the northern shore of Lake Michigan, then steered south-west until they reached the mouth of the Menominee river, flowing into Green Bay. Here they rested for a brief period among friendly Menominees, who tried to persuade them to give up their venture. According to the Menominees, the banks of the Mississippi were infested by savage tribes who tortured and slew all intruders into their domains. As this did not seem sufficient to discourage Jolliet and Marquette, they added that demons haunted the land bordering the river and monsters the river itself, and that, even if they escaped savages, demons, and monsters, they would perish from the excessive heat of the country Both Jolliet and Marquette had heard such stories from Indians before. Pressing on to the south end of Green Bay, they entered the Fox river and ascended it until they reached Lake Winnebago. After crossing this lake they continued westward up the extension of the Fox. They were now in the land of the Mascoutens and Miamis. The country teemed with life; birds filled the air with whirr of wing and with song; as the voyagers paddled ever westward deer and elk came from their forest lairs to gaze with wondering eyes at these unfamiliar intruders on their haunts. The Mascoutens were friendly, and supplied the travellers with bison flesh and venison, and with guides to direct them over the watershed to the Wisconsin. They carried the canoes over a forest trail, and launched them on this river; and then with exulting hearts swept forward on the last stage of their journey to the Mississippi. At length, on the 17th of June, they reached the great river and landed at the place where now stands Prairie du Chien. They had the feeling of conquerors, but of conquerors whose greatest battle has yet to be fought. Out of the far north came this mysterious river; but whither did it go? Did these waters sweep onward till they lost themselves in the Pacific, or did they pour into some southern bay of the Atlantic? Such were the questions that agitated the minds of these first of Frenchmen to gaze on the 'Father of Waters,' [Footnote: It is thought possible that in 1658-59 Pierre Esprit Radisson and Medard Chouart des Groseilliers crossed the Mississippi while hunting furs in the country west of Lake Superior; but there is an element of doubt as to this. Save for the Spaniards, Jolliet and Marquette were the first white men on the Mississippi, so far as known.] questions that were not to be laid at rest until La Salle, nine years later, toiled down the river and from its mouth viewed the wide expanse of the Gulf of Mexico.

After a brief rest the party launched their canoes and for over a week drifted downward with the current, anchoring their canoes in mid-stream at night for fear of an attack by hostile Indians. But during this time they saw no human beings; the only living things that caught their eyes as they sped past forest and plain were the deer browsing along the banks, the birds circling overhead, and immense herds of buffalo moving like huge armies over the grassy slopes. At length they reached a village of friendly Illinois, and here they were feasted on fish, dog, and buffalo meat, and spent the balmy midsummer night in the open, sleeping on buffalo robes. While at this village, Marquette, who had a rare gift of tongues, addressed the Illinois in Algonquin, and thus preached the Gospel for the first time to the Indians of the Mississippi. Here their hosts warned them of the dangers they were going to—death from savages or demons awaited them in the south—and presented them with a calumet as a passport to protect them against the tribes below.

After leaving this village the explorers came upon a 'hideous monster,' a huge fish, the appearance of which almost made them credit the stories of the Indians. According to Marquette: 'His head was like that of a tiger, his nose was sharp, and somewhat resembled a wildcat; his beard was long, his ears stood upright, the colour of his head was grey, and his neck black.' Onward swept the explorers past the mouth of the Illinois. A few miles above the present city of Alton they paused to gaze on some high rocks on which fabulous creatures were pictured. 'They are,' wrote Marquette in his narrative, 'as large as a calf, with head and horns like a goat; their eyes red; beard like a tiger's, and a face like a man's. Their tails are so long that they pass over their heads and between their forelegs, under the belly, and ending like a fish's tail. They are painted red, green, and black.' The Indians of the Mississippi were certainly not without imagination and possessed some artistic skill. No doubt it was these pictured rocks that had originated among the Menominees and Illinois the stories of the demons with which they had regaled Marquette and Jolliet.

While the voyagers were still discussing the pictured rocks, their canoes began to toss and heave on rushing waters, and they found themselves in the midst of plunging logs and tumbling trees. They were at the mouth of the Missouri. As they threaded their way past this dangerous point, Marquette resolved that he would one day ascend this river that he might 'preach the Gospel to all the peoples of this New World who have so long grovelled in the darkness of infidelity.'

Onward still into the unknown! At the mouth of the Ohio—then called by the Indians the Ouabouskigon [Footnote: This word, as well as the word Ohio, or O-he-ho, means 'The Beautiful.']—they drew up their canoes to rest and then advanced a little farther south to an Illinois village. The inhabitants of this village wore European clothing and had beads, knives, and hatchets, obtained no doubt from the Spaniards. The Indians told the explorers that the mouth of the river was distant only a ten-days' journey, whereas it was in reality a thousand miles away. But with increased hope the Frenchmen once more launched their canoes and went on until they came to the mouth of the Arkansas. Here they met with the first hostile demonstration. Indians, with bows bent and war-clubs raised, threatened destruction to these unknown whites; but Marquette, calm, courageous, and confident, stood up in the bow of his canoe and held aloft the calumet the Illinois had given him. The passport was respected and the elders of the village, which was close at hand, invited the voyagers ashore and feasted them with sagamite and fish. Leaving this village, they pressed southward twenty odd miles to another Arkansas village. The attitude of the Indians here alarmed them, and this, with the apprehension that the mouth of the Mississippi was much farther away than they had been led to believe, decided them to return.

Jolliet and Marquette were now satisfied with what they had achieved. The southward trend of the river proved conclusively that it could not fall into the Gulf of California, and, as they were in latitude 33 degrees 41 minutes, the river could not empty into the Atlantic in Virginia. It must therefore join the sea either on the coast of Florida or in the Gulf of Mexico. Moreover, to proceed farther would but add weary miles to the difficult return journey. But the chief reason for turning back is best given in Marquette's own words:

We considered that the advantage of our travels would be altogether lost to our nation if we fell into the hands of the Spaniards, from whom we could expect no other treatment but death or slavery; besides, we saw that we were not prepared to resist the Indians, the allies of the Europeans, who continually infested the lower part of the river.

On the 17th of July, just one month after they first sighted the waters of the Mississippi, the explorers turned their canoes northward. A little south of the Illinois river some friendly Indians told them of a shorter way to Lake Michigan than by the Wisconsin and Fox river route. These Indians were anxious to have Marquette remain with them and establish a mission. He was unable to comply with their request, for in the miasmal region of the lower Mississippi he had contracted a severe malarial fever; but he promised to return to them as soon as his health permitted. The explorers were now joined by a chief and a band of Indians as guides to Lake Michigan, and with these they ascended the Illinois and then the river Des Plaines. From the river Des Plaines they portaged their canoes to the Chicago river and descended it to Lake Michigan. They arrived at Green Bay at the end of September, having travelled in all, since leaving this spot, over twenty-five hundred miles. Marquette was too ill to go farther; and he remained at Green Bay to recruit his strength, while Jolliet hastened to Quebec to report to Frontenac the results of his expedition. Unfortunately, the canoe in which Jolliet travelled was upset in the Lachine rapids and the papers containing his charts and the account of his journey were lost; however, he was able to piece out from memory the story of his Ulysses-like wanderings.

By the autumn of 1674 Marquette thought that he had completely recovered his health, and, having received permission from his superior, he set out for the Illinois country on the 25th of October to establish the mission of the Immaculate Conception. He was accompanied on this journey by two assistants—two true heroes—known to history only as Pierre and Jacques, and a band of Potawatomis and Illinois. In ten canoes the party paddled southward from Green Bay, for nearly a month buffeting the tempestuous autumn seas of Lake Michigan. They ascended the Chicago river for six miles and encamped. Marquette could go no farther; he was once more prostrated with illness, and a severe hemorrhage threatened to carry him off. But his valiant spirit conquered, and during the winter he was able to minister to some Illinois, who were encamped a short distance away and who paid him occasional visits. By the spring he had so far recovered that he decided to undertake the journey to the Mississippi, his heart set on founding a mission among the tribes there. On the 13th of March he and his two helpers broke camp and portaged their canoe to the Des Plaines. Near the junction of this river with the Illinois was the Indian town of Old Kaskaskia. The Indians of this town gave him a welcome worthy of a conqueror, such as indeed he really was. He went among them teaching and preaching; but brain and body were burning with fever; he felt that he had not long to live, and if he would die among his own people he must hasten home. He summoned the Indians to a grand council. And, in one of God's first temples—a meadow decked with spring flowers and roofed by the blue vault of heaven—he preached to a congregation of over three thousand—chiefs, warriors, women, and children. His sermon finished, he blessed his hearers, and, leaving his words to sink into their hearts, bade them farewell.