We had gone 31,500 m. that morning. When we found a most beautiful beach of lovely sand we could not resist the temptation of halting on it to prepare our lunch. Our surprise was great when we set foot on the beach to hear shrill whistles beneath us. The beach was formed of whistling—or singing—sand. The reason the sand was musical was because some large insects had bored thousands of holes of great depth into its moistened mass, which allowed the holes to retain their form. When the sand was trodden the pressure drove the warmish air contained in those holes with great force through the contracted apertures and caused a sharp whistling and occasionally quite melodious notes.
I again took observations for latitude and longitude at this place, but I was beginning to find the work too heavy—not the observing in itself, but the computing of all the observations, at which I was not particularly quick. (Lat. 9° 24′ S.; Long. 58° 40′ W.) Also, the great care which I had to take of the chronometer under most difficult circumstances was a trial to me, considering the numberless things I had to look after. The only little comfort I had on that journey had been my camp bed, on which I could, if not sleep soundly, at least rest my weary bones for a few hours at night. That had now gone, and I was beginning to feel the strain of the hard work, constant mental exertion, and the total lack of rest.
We had passed a great number of islands in the morning: one 2,000 m. long—Melusine Island; another 300 m.—Janus Island; a third 3,000 m.—Midas Island—by the side of which was another enormous island, some 6,000 m. in length—Miranda Island. Then little islets 200 and 250 m. long, and another big island, 2,000 m. from end to end—A. Masõ Island.
Most beautiful sandy beaches were now constantly seen, mostly, like the one on which we had landed, composed of singing sand. (Some of those beaches were 200 and 300 m. long.) The beach on which we had landed for lunch was at the southern end of a great island, 5,700 m. long, which I named Queen Mary Island.
We left again that afternoon, travelling fairly speedily, chiefly in W.N.W. and S.S.W. directions, varying from 290° b.m. to 230° b.m. When we came to the end of Queen Mary Island, after passing some really remarkable beaches on which we found a great many turtles' eggs, we came to a large basin, 1,800 m. across, with numberless rocks scattered on the north and south sides of it. The river there flowed due west; in fact, those rocks formed a kind of corona all around the great circle. A crescent-shaped island, 2,800 m. long—Giselle Island—was next passed. The channel through which we went was full of dangerous rocks, and had a width of 280 m.
Soon after another basin 1,600 m. broad was reached, with a formidable barrier of islets and rocks spreading from south to north. The river there flowed in a perfectly straight course for 10 kil. to 310° b.m. A most extraordinary-looking islet with a circular terrace of rock on the east side of it, which was passed in mid-stream, was surrounded by a giant crown of pyramidal rocks of great height emerging in sharp points from the water. We had gone but 6,000 m. of that distance when we came to an island on the right side with a gorgeous spit, also of musical sand, 300 m. long. The island itself was only 700 m. long including the sand-spit—Kuvera Island. We were then in an immense basin with leaden waters as still as those of a pond.
We made our camp in a most picturesque spot, an immense beach forming innumerable indentations, really like small dunes of sand deposited by water. The accurate elevation of that place was, according to the observations taken with the hypsometrical apparatus, 967 feet, water boiling at that spot at 210° 3¾, and the temperature of the atmosphere being 72½° F. The indented beach, not unlike a giant double-comb, was at the beginning of a great island which I named James Dewar Island, in honour of the great discoverer of liquid air. The minimum temperature during the night of July 29th was 55° F.
Since we had come to the enormous sand accumulations along the stream the troublesome insects which worried us day and night seemed to have doubled or trebled in numbers, and we suffered positive torture from them, especially when we landed anywhere.
A Narrow Passage in the Arinos River.