Page:Popular Science Monthly Volume 45.djvu/41

Rh by the ascending currents of air. Each globule shone with light, and looked almost as white as a snowflake. As they approached the nest few seemed to touch it, but curved away from it in some eddy of the air, and settled down into the depths of darkness below. During the rain both birds remained in the chimney most of the time. Sunday, July 16th, proved to be an unusually warm day, and, what was perhaps of more moment to the swifts, a very dry day, there seeming to be no moisture left in air or vegetation. About noon, while writing at my table, I heard the familiar booming, whistling, and chirping in the chimney, and as I glanced up I saw that one of the birds was coming to the nest and the other just going off up chimney. Suddenly there was a grating sound, a sharp outcry, more booming and fluttering, and I jumped to my feet and knelt before the glass to gain a closer view of the chimney. The nest had vanished. Only a tiny piece of glue adhered to the slight curve in the bricks under which the nest had been attached. The parent bird, with ruffled plumage and rapidly moving head, clung near the spot where her home had been, and seemed to me to be looking with terror far down into that horrible abyss where her young had fallen, and from which they sent back no cry. Taking down the pointed rod, I used the small mirror to search every part of the great chimney cavern which could be reached, but in vain. The nest had gone straight down without touching any fireplace, and had been lost forever in the débris and stifling dust at the bottom of the shaft.

During the remainder of the day the birds fluttered back and forth and lamented. They did not go more than two or three inches below the spot where the ill-fated nest had been. At intervals during the night I heard them moving in the chimney, but on Monday they stayed away most of the time, even during a heavy shower which fell late in the afternoon. Toward evening I saw both of them perched near the site of their fallen home, and during that night and on other days and nights the sound of their wings occasionally came to me as a reminder of their vanished happiness. They made no effort to rebuild in my chimney, yet their presence in it seemed to show that they had not begun housekeeping elsewhere. I doubt not that another summer, that love of home which is so closely connected with birds' ability to find a familiar spot by day or by night, even after months of absence, will bring my swifts back to their old flue.

appears from the altitudes of the highest clouds measured at Upsala, Sweden, Kew, England,and Blue Hill, Mass., that the upper limit of ordinary clouds in temperate latitudes is between thirteen and fifteen kilometres, or nine miles; but it is possible that more numerous measurements may extend it to ten miles.