3i8 



NATURE 



{Aug. lo, 1876 



Kidder's collection contains examples of twenty-one 

 species of this class, belonging to six families, namely, 

 eleven Petrels, four Penguins, three Gulls, a Cormorant, 

 a Duck, and a Sheath-bill. Of these, the two last-named 

 are " the only partial vegetable feeders observed, all the 

 other birds feeding exclusively on flesh, fish, or marine 

 invertebrates," Of the Chionis, or Sheath-bills, a singular 

 abnormal form related to the Plovers, of which there are 

 (or were lately) living specimens in the Zoological So- 

 ciety's Gardens, Dr, Kidder might well have sung, in the 

 words of the old song, " their tameness is shocking to me." 

 "They would scarcely get out of my way," says the Doctor, 

 " and seemed greatly interested in my movements. When 

 I sat on a stone, keeping perfectly still, the whole party, 

 twelve in all, came up to examine the intruder. They 

 walked all around me, coming almost within reach ; 

 others flying up from more distant rocks to join them, 

 and finally stopped, almost in a semi-circle, for a good 

 stare. After watching the birds for a time, I shot four 

 specimens, not without compunction, on account of killing 

 such trustful acquaintances. When I walked off to get a 

 sufficient distance away for a shot, the whole troop started 

 to follow me, making little runs and stopping, as if filled 

 with curiosity. I shot all four without moving from the 

 spot, reloading for each, the birds not all flying out of 

 range even after the gun had been fired. On subsequent 

 occasions, various members of the party captured speci- 

 mens by hand ; all that was necessary to attract them 

 within reach being to remain perfectly still. After one 

 had been caught it served as a lure for others. When 

 taken home alive they still showed no fear, but when let 

 loose in the house took food readily." 



Another curious fact observed is that in the absence of 

 true birds of prey in Kerguelen's Land, the Skua of the 

 Southern Seas (which Dr. Coues, widely departing from 

 the ordinary binomial system designates as " Buphagtis 

 skua aiitarcticus (Les.), Coues "), appears to have taken 

 upon itself all the habits and practices of a Buzzard or 

 Kite. " It was at first taken for a hawk by all of us ; 

 its manner of flight, watchfulness of the ground over 

 which it flew, and habit of perching on spots com- 

 manding a wide view, all suggested this impression. It 

 was, indeed, difficult to believe the evidence of my own 

 senses when I found a web-footed bird avoiding the 

 water and preying solely, so far as my observations 

 extended, upon other birds. When any of the party went 

 out shooting he was pretty sure to be followed by one or 

 two ' sea-hens,' as the sealers call them, and had often to 

 be very prompt to secure his game before it should be 

 carried off in his very presence." 



Many details are likewise given respecting the habits of 

 the other nineteen species observed, and great credit is due 

 to Dr. Kidder and Dr. Coues for the speedy manner in 

 which they have put together this interesting memoir. 

 But what Mr. Eaton, the English naturalist at Kerguelen, 

 and Mr. Sharp, who, we believe, has been, or is working 

 out his birds, will say to it, we cannot tell. We fancy they 

 will not be very much pleased at being thus forestalled. 



MAYER'S RECENT ACOUSTICAL 

 RESEARCHES 1 



'"PHIS communication is merely a preliminary note, to be 

 ■^ followed by an elaborate paper on the above subjects. For 

 conciseness and clearness, I present the few facts I have now to 

 offer in the form of notes of experiments : — 



I " On the Obliteration of one Sonorous Sensation by the simuUaneous 

 action of another more intense and lower Sound, and on the discovery of 

 the remarkable fact that a Sound, even when very intense, cannot obliterate 

 the sensations of another Sound Lower than it in Pitch ; with Applications 

 of these Discoveries to Measures of the Intensities of Sounds, and to the 

 Proper Method of Conducting Orchestral Music." By Alfred M. Mayer, 

 Ph D., Member of the National (American) Academy of Sciences, and Pro- 

 fessor of Physics in the Stevens Institute of Technology. Hoboken, New 

 Jersey, U.S. America. Read before the National (American) Academy of 

 Sciences, in Washington, April 20, 1876, and now first prmted from the 

 manuscript sent through Mr. Alex. J. Ellis, F.R.S. 



Experimental Observations on the Obliteration of one Sound 

 by another. — Several feet from the ear I placed one of those 

 loud-ticking spring-balance American clocks, which make four 

 beats in a second. Then I brought quite close to my ear a 

 watch (made by Lange, of Dresden) ticking five times in the 

 second. In this position I heard all the ticks of the watch, 

 even those which coincided with every fourth tick of the clock. 

 Let us call the fifth tick of the watch which coincided with one 

 of the ticks of the clock, its fifth lick. I now gradually removed 

 the watch from the ear, and perceived that the fifth tick became 

 fainter and fainter, till at a certain distance it entirely vanished, 

 and was, so to speak, *' stamped out " of the watch. ^ 



Similar and more striking experiments were made with an 

 old silver watch, beating four times to the second, by causing 

 this watch to gain about thirty seconds an hour on the clock, so 

 that at every two minutes the ticks of the watch and clock ex- 

 actly coincided. When the watch was held near the ear, every 

 one of its ticks was heard distinctly ; but on gradually removing 

 it from the ear, the ticks of the watch became fainter and fainter 

 at the coincidences, and when the watch had been i-emoved to a 

 distance of nine inches from the ear, the ticks of the watch 

 were utterly obliterated during three whole seconds of its ticks 

 about the time of coincidence. On removing the watch to a 

 distance of twenty-four inches, I found that I lost its ticks during 

 nine seconds about the time of coincidence. It is here impor- 

 tant to remark that the ticks of the clock are longer in duration, 

 as well as lower in pitch, than those of the watches. With the 

 watch remaining at the distance of twenty-four inches from the 

 ear, I listened with all my attention, as tick by tick the watch 

 approached the time of coincidence. Since the ticks of the watch 

 are shurter in duration than those of the clock, they are overlapped 

 by the other about the time of coincidence. Hence as, so to 

 speak, the short ticks of the watch glided, tick after tick, under 

 the long ticks of the clock, I perceived that more and more of 

 the duration of each successive watch-tick became extinguished 

 by the tick of the clock, until only the tail end of the short tick 

 of the watch was left audible, and at last even this also crept 

 under the long tick of the clock, and the whole of the ticks of 

 the clock were rendered inaudible for nine seconds, at the end 

 of which time the front or head of the watch-tick, as we 

 may call it, protruded beyond the clock-tick, and then slowly 

 grew up into a complete watch-tick as before. In this succession 

 of events the tick of the old silver watch (made by Tobias) dis- 

 appears with a sharp chirp, like a cricket's, and re-appears with 

 a sound like that made by a boy's marble falling upon others in 

 his pocket. By this experiment, therefore, a gradual analysis is 

 made of the effect of the tick of the clock on the tick of the 

 watch, affording a beautiful illustration of the fact that one sono- 

 rous sensation may overcome and obliterate another. 



Experiments to determine the relative intensity of the Clock- ticks 

 which obliterate three Watch-ticks. — The clock was placed on a 

 post in the middle of an open level field in the country, on 

 nights when the air was calm and noiseless. The ticks of the 

 clock became just inaudible when my ear was removed to a 

 distance of 350 feet. The ticks of the watch became just inau- 

 dible at a distance of twenty feet. The ratio of the squares of 

 these numbers makes' the ticks of the clock about 300 times more 

 intense than those of the watch. On the same nights that I 

 made the above determinations I also put the clock on the post, 

 and placing against my zygomatic process a slender stick gra- 

 duated to inches and tenths, I stood with my ear at distances 

 from the clock of from eight to sixteen feet, and then slid the 

 watch above and along the stick (taking care that it did not 

 touch it) until it reached such a distance from the ear that its 

 fifth tick just disappeared. Knowing the relative intensities of 

 the ticks of clock and watch when placed at the same distance 

 from the ear, the law of the reciprocals of the squares gives the 

 relative intensities when the clock and watch are at the several 

 distances obtained in the above experiments. Large numbers of 

 such experiments have been made, and the results agree per- 

 fectly well when we take into consideration first, the difficulty 



I The precise number of ticks in a second here mentioned are not neces- 

 sary for roughly observing and understanding these phenomena. I observed 

 them by a common American pendulum clock placed on a table, which in- 

 creased the power of its half-second ticks, and a watch beating five times in 

 two seconds. Rev. Mr. Haweis informs me that he has often noticed a 

 similar effect at night with ordinary watches. The sensation produced by 

 the obliteration of the tick, when the proper distance of the watch from the 

 ear has been attained, and the consequent sudden division of the ticks into 

 periods separated by silences, is very peculiar. It is difficult not to believe 

 that some accident has not suddenly interfered with the action of the watch, 

 instead of merely with our own s.nsat'ons.— A. J. E. 



