25o THE POPULAR SCIENCE MONTHLY. 



besides eruptions there are also volcanic explosions like those 

 which our generation has witnessed at Krakatoa in 1883, Bang- 

 taisom in 1887, and which our fathers observed at Temboro in 

 1832. If we reflect that the explosion of Krakatoa threw 16 cubic 

 kilometres of matter into the air, and that of Temboro was still 

 more considerable, we may be permitted to say that volcanic ac- 

 tion, instead of diminishing, adds to the constant degradation of 

 the continental relief. 



I have not assumed to give precise figures on this subject. My 

 object is less to exhibit numerical results than to present a view 

 of the relative magnitude of the effects under analysis. It is evi- 

 dent that these effects can not be neglected, and that they permit 

 us to assign to the geological history of our globe a duration less 

 than the somewhat fantastic figures to which we have been occa- 

 sionally asked to give credit. 



It is nevertheless true that the disappearance of the continental 

 relief, while it may receive the attention of the geologist and 

 thinker, is not one of those events concerning which present gen- 

 erations need trouble themselves. Neither our children nor our 

 great-grandchildren will have a visible prospect of it presented 

 to them as an actual danger. Translated for the Popular Science 

 Monthly from del et Terre. 



THE MUSIC OF THE BIRDS. 



By SIMEON PEASE CHENEY. 



HEN MUSIC. Late, one night, as I chanced near the hen- 

 nery with a light, I was rewarded by an exquisite exhibi- 

 tion of the communicative ability of our domestic fowls. The 

 hens moved on their perches; when the rooster spoke, rousing 

 them still more. Stepping back, I soon heard a little sound, 

 high and " exceeding fine," with a deceiving, ventriloquous qual- 

 ity. Long spun, and then bent down in a graceful descent of 

 the interval of a sixth, it terminated in a more decided tone, a 

 peculiar tremor something less than a trill, and died away in 

 a beautiful diminish : 



This model example in pianissimo practice, and in the art of 

 holding the breath, proved to come from one of the hens ; and, 

 though the exact tones are here represented, no idea can be con- 

 veyed of the unique, perfect performance. The quieting effect on 



