Page:Popular Science Monthly Volume 39.djvu/267

Rh At first thought, it was some bird that had practiced under a cuckoo master. It was an anxious moment, but presently all was settled:

The instant I heard "cuckoo," more especially the second one, giving the interval of a fourth, I experienced a thrill of satisfaction such as no similar discovery had afforded. Other ears, sharper than mine, had heard all, unknown to me, and there was great rejoicing; the cuckoo was learning to sing.

.—The yellow-billed cuckoo, though he tries hard to make a showing of vocal talent, succeeds only in producing a slovenly, guttural blubbering, with barely tone enough to give positive pitch. The beginning of this effort is a sepulchral and somewhat protracted sound, which bursts into several rapid, boisterous bubbles, followed by others softer and slower, farther and farther apart:

The yellow-breasted chat exhibits the same rhythmic pecul-iarity in his chattings, and so does the woodpecker, drumming on a board or dry limb for the mere sound of it; but in quality nothing can be compared with this slopping performance, unless it be that of the loose-mouthed hound lapping from a pan of milk.

The cuckoos, graceful, beautiful birds, and ever rapt in solemn reverie, are solitary voices, seldom heard more than one at a time.

carried on for nearly two years at the observatories of Berlin, Potsdam, and Prague indicate the existence of a periodical oscillation in latitude. The maximum occurs in summer, the minimum in winter, and the amount is 0′ 25″. The observations have been conducted with the greatest exactitude, and the results of the three sets are concordant. M. Gaillot has communicated a similar result from observations taken at Paris between 1856 and 1861. The variation may be ascribed to a periodical displacement of the earth's axis, in which case, while the amplitude of the phenomena will be the same at all stations, the times of maxima and minima will vary with the longitude; or it may be an effect due to refraction, in which case the periods will be the same at all the stations.