170 



NATURE 



[December 8, 1910 



theor_v is certain to form the basis of a careful and com- 

 plete series of investigations, not only in Europe, but also 

 in those regions in Africa and America where pellagra 

 also occurs, these experiments and results on the destruc- 

 tion of the Simulium larva; will be of no little practical 

 importance in the prophylaxis of the disease, whether a 

 definite pathogenic organism is discovered, or the case 

 proves to be analogous to that of Stegomyia or yellow 

 fever. C. Gordon Hewitt. 



Division of Entomology, Ottawa, November 21. 



The Song of the Siamang Gibbon. 



The Zoological Society has recently received on loan an 

 almost adult example of the siamang {Symphalangus 

 syndactylus) ; and since I can find no adequate description 

 of the voice of this ape in the books I have consulted, I 

 think the following description may be interesting to 

 readers of Nature. 



The siamang differs from all other gibbons in having 

 a pair of laryngeal vocal sacs visible externally on the 

 throat as an undivided pouch of loose skin. When the 

 animal is in full song the pouch becomes inflated into an 

 immense oblate spheroid much wider from side to side 

 than from above downwards, and comparable in size to 

 the entire head of the gibbon. A feeble imitation can be 

 made of the booming that comes from this pouch by 

 uttering a guttural monosyllabic " 000 " with cheeks in- 

 flated and lips compressed. It is not unlike the sound 

 produced by a large bubble of air bursting on the surface 

 of water confined in a narrow space like a rain-water 

 pipe. In addition to this there are two very distinct cries 

 apparently quite independent of the vocal sac and uttered 

 with the mouth open. One is a shrill, piercing bark, like 

 the monosyllable " haow," cut off sharply by the abrupt 

 closing of the lips. The other is a prolonged, unearthly 

 wailing shriek — " ahh — o " — resembling more than any 

 familiar sound to which I can compare it the " miaou " 

 of a cat multiplied ten times in volume. It starts on a 

 high pitched note with the mouth widely astretch, and 

 gradually descends the scale as the jaws are closed. 

 There are two variations of this shriek, one being a note 

 or two higher and more piercing than the other. 



The song usually begins with a low and gentle booming 

 punctuated by an occasional staccato bark. As the excite- 

 ment rises the ape starts to move, and swings round the 

 cage barking vigorously and repeatedly, and now and again 

 uttering the wailing shriek, the loud booming from the 

 now fully expanded vocal sac going on all the while like 

 a resonant bass accompaniment. The noise is deafening 

 and terrific, and I shall not easily forget the consternation 

 of the chimpanzees and the look of mild surprise that 

 pervaded the usually expressionless faces of the orang- 

 utans when they heard it for the first time in the apes' 

 house. 



The voices of Mammalia have never, I believe, been 

 carefully studied and compared ; yet they are worthy of 

 the closest attention as a criterion of specific relationships. 

 The cry of the siamang, for instance, is quite different 

 from that of the Hainan, Hoolock, and Wau-wau gibbons, 

 and each of these species has its characteristic song. I 

 have elsewhere pointed out that the bray of Gravy's zebra 

 betrays pronounced asinine affinities, and equally forcibly 

 attests remoteness of kinship between that species and the 

 quaggine Equidai ; that the likeness between the roar of 

 the lion and the tiger on one hand and of the jaguar and 

 the leopard on the other confirms the conclusion that these 

 species are respectively closely allied, and that these four 

 great cats form, with the probable inclusion of the ounce, 

 a special group of Felis characterised by a roaring voice 

 correlated with a peculiarly modified hyoidean apparatus ; 

 that the friendly purr practised by the puma, cheetah, 

 caracal, common cat, and other species which, be it noted, 

 never roar, distinguishes them from lions, tigers, and 

 leopards, which never purr. To the casual observer the 

 Cape hunting dog (Lycaon) is more like a hyaena than a 

 wolf, but the moment he barks and growls it is needless 

 to look at his teeth and skull to detect his cousinship to 

 Canis ; and I have recently noticed identity in all essential 

 respects between the raucous growl of a frightened cervine 

 wallaroo (Macropus) and that of a nervous Tasmanian 

 wolf (Thylacinus). In this last instance we have vocal 



NO. 2145, VOL. 85] 



likeness associated with deep-seated ordinal resemblances, 

 and apparently persisting despite great divergences in 

 other structural features and in habits. 



Zoological Society. R. I. PococK. 



On the Simultaneity of "Abruptly-beginning" 

 Magnetic Storms. 



In the first number of Terrestrial Magnetism and 

 Atmospheric Electricity for the present year, Dr. Bauer 

 has written two papers, in which he believes he can prove 

 the following (p. 20) : — 



" Magnetic storms do not begin at precisely the same 

 instant all over the earth. The abruptly beginning ones, 

 in which the effects are in general small, are propagated 

 over the earth more often eastwardly, though also at times 

 westwardly, at a speed of about 7000 miles per minute, 

 so that a complete circuit of the earth would be made in 

 32 or 4 minutes." 



Dr. Bauer bases this result upon an investigation of two 

 magnetic storms of Birkeland's " positive equatorial " 

 type, namely, the storms of May 8, 1902, and January 26, 

 1903. In the latter he makes use of a table in Birkeland's 

 " The Norwegian Aurora Polaris Expedition, 1902-3." 



In the following number Dr. Faris made a mori:' 

 thorough investigation of this circumstance, taking fifteen 

 different abruptly beginning storms, recorded at the Coast 

 and Geodetic Survey magnetic observatories, in which he 

 considers that he found Dr. Bauer's result confirmed. 



Upon this foundation Bauer then develops the *' Ionic 

 Theory of Magnetic Disturbances" (loc. cit., p. iii), of 

 which the principal advantage over Birkeland's corpuscular 

 theory is supposed to consist in the being able to give a 

 natural explanation to time differences such as these, which 

 Birkeland's theory, in his opinion, cannot do. 



Notices of these papers appeared in Nature of August 1 1 



.A.S it appears that a number of the perturbatior 

 described by Dr. Faris are some that I studied las 

 summer when making an investigation of magnetic equa- 

 torial storms at the magnetic observatory in Potsdam, a 

 comparison may be of some interest. I determined also 

 the time of the commencement of a number of positive 

 equatorial storms as accurately as possible for another 

 purpose, and without any knowledge of Dr. Faris 's work, 

 so that the measuring of the time was entirely independent 

 of it, a circumstance which may be worthy of note. 



It may be remarked with regard to the exactness with 

 which the time can be determined by the Potsdam curves 

 that the length of an hour upon the magnetograms is about 

 20 mm., and that thus one minute answers to about 5 mm. 

 If we then take into consideration all the errors that may 

 creep in because the curves, the time-marks, and the points 

 considered are not so sharply defined as might be wished, 

 and further all the errors that may be due to changes 

 in the paper in developing, owing to the fact that the 1 

 paper has perhaps not laid quite straight on the roller. 

 Sec, it will be evident that where there are no exact 

 automatic time-marks upon the curve itself, one minute 

 will at any rate be the lowest limit for the accuracy that ' 

 under favourable conditions can be counted upon. 



There might very easily be an uncertainty of severa, 

 minutes if, for instance, the base-line is not exactly l 

 straight, but is slightly curved, if the parallax cannot be r 

 determined exactly, and so forth. Unfortunately, neith' - 

 Dr. Bauer nor Dr. Faris has stated anything as to ho- 

 the time in the various cases can be given exactly, a pois 

 upon which, it would be thought, it was highly importai 

 to be clear. 



In the equatorial storms that I have studied, aivl 

 especially those that are also found in Dr. Faris 's Table 1. 

 (loc. cit., p. loi), the point at which they commenced is ; 

 especially clear in H. • The deflections in D and Z, on the 

 other hand, are very slight, and in consequence th'' 

 beginning there is far less clearly defined. 



It is therefore the beginning in H that is espccial!- 

 suitable for employment in a comparison such as this, and 

 this was what I especially investigated. It will a priori 

 be perceived that the results obtained by employing th>- 

 other two components must be far more uncertain. I' 

 the table below I have compared the means of the value- 

 found by Faris for the five American stations that he has 

 considered with those I measured out bv the aid of thf 



