June 19, 1890] 



NATURE 



191 



could be heard. A wave siren was also used to illustrate the 

 same fact. The matter was further illustraled by moving a 

 luning-fork towards a wall or other reflecting surface at various 

 velocities. According to Doppler's principle, as the fork recedes 

 from the observer and approaches the wall, the frequency of 

 the direct waves is less and that of the reflected waves greater 

 than that of the fork, and these two series of waves produce 

 beats. By sufficiently increasing the velocity and using a fork 

 of high pitch, the beats blend into tones. Coming to the second 

 half of Dr. Koenig's researches, Dr. Thompson said that Helm- 

 holtz contended that the timbre of musical sounds was not 

 affected by differences of phase amongst the component tones ; 

 on this point, however, Kcenig had come to the opposite con- 

 clusion. To illustrate graphically why phase should affect 

 timbre, a number of diagrams were exhibited, some showing the 

 resultant wave-form produced by combining a tone with its 

 harmonics of equal intensity, when the differences of phase 

 between them were o, \, \, and \ respectively ; whilst others 

 represented the wave-forms when the harmonics and the funda- 

 mental were of different intensities. The effect of phase on the 

 shape of the waveform was very marked. The subject was 

 treated experimentally by means of a wave siren, against which 

 a stream of air issuing from a slit could be directed. By inclin- 

 ing the slit to one side of the radius or the other, the phases of i 

 the component waves could be altered, and this had a marked 

 effect on the character of the sound produced. Illustrations of 

 Kixnig's multiple wave sirens, both of the cylinder and disk 

 forms, were next shown, and the results of investigations made 

 with the apparatus described. From these results it appears to 

 lie impossible to produce the timbre of instruments such as 

 trumpets, clarionets. &c., by any combination of a tone and its 

 pure harmonics. This led to the investigation of impure har- 

 monics. By plotting and combining curves it was shown that | 

 the wave-form obtained from a tone and impure harmonics j 

 clianges in successive periods ; this peculiarity was observed 

 to exist in a record taken from a vibrating string. Various disks 

 with wavy edges of different form were spun before an air slit, j 

 and the varying character of the resulting sounds as the slit was 

 turned, demonstrated. Before concluding. Dr. Thompson re- | 

 marked that the word "///«/^;v" requires to be re-defined, for 

 the rigidity of strings, wires, &c., and the interference of the 

 wood and metal parts of organ pipes and other wind intruments 

 generally, prevent the formation of pure harmonics. A model 

 consisting of vibrating strips placed vertically or inclined was 

 exhibited to show the different kinds of timbre. The differences 

 between mixtures and compounds of tones was pointed out, and 

 the inability of the ear to distinguish between pure and impure 

 siiunds referred to. Lord Rayleigh thought more information 

 was required on the important subjects brought forward, and 

 asked in what class of musical sounds are the overtones strictly 

 harmonious. He could admit that in piano wires they may not 

 be so, but he was not quite so clear about organ pipes. He said 

 he was filled with admiration by the perfection of the appa- 

 ratus displayedr and expressed a wish that such mechanical 

 acousticians could be found on this side of the Channel. Mr. 

 Bosanquet said he had been carefully over the ground investigated 

 by Dr. Kcenig. He believed Dr. Kcenig was the first to get at 

 tlie facts concerning beats, but it was difficult to admit all that 

 had been said about them. However, the chief difference between 

 authorities seemed to be one of language. Owing to the lateness 

 of the hour he could not discuss the question fully, and so asked 

 to be allowed to reserve his opinion on the matter. As regards 

 timbre, he thought the experiments on the effects of phase 

 were not conclusive. The sounds of wind instruments such as 

 trumpets, he said, depended greatly on who produced them. 

 It was no easy matter to bring out their full sweetness, and it 

 was comparatively few persons who could ever attain perfection. 

 1 Ic ventured to think that in a properly used instrument none of 

 the harmonics are out of tune. Mr. Blaikley agreed with Lord 

 Rayleigh about piano wires, and as regards wind instruments he 

 could hardly think that the overtones were so inharmonious as 

 Dr. Thompson would have him believe. In fact, Mr. Stroh 

 liad obtained wave-forms for him from various instruments, but 

 in none of them was there any discontinuity such as shown on 

 'ine of the diagrams exhibited. However, he was of opinion 

 that there is something in timbre not accounted for by the 

 "rlinary theory. The President said that in view of the pro- 

 ■ hictlon of audible sounds by the beats from notes beyond the 

 range of audition, it might be possible to demonstrate that 

 In-ects produce sounds inaudible to the human ear by putting 



NO. 1077, VOL. 42] 



several together in a box, and listening for the beat-tones. 

 Dr. Kcenig acknowledged the most cordial vote of thanks 

 accorded to himself and Dr. Thompson. 



Zoological Society, June 3.— Prof, W, H. Flower, F.R.S., 

 President, in the chair. — The Secretary read a report on the ad- 

 ditions that had been made to the Society's Menagerie during 

 the month of May 1890, and called special attention to a pair 

 of Hartebeests {AlcetapJnis caavia), and a pair of Swainson's 

 Long-tailed Jays (Calocitta fortnosa), acquired by purchase ; and 

 to a pair of Beatrix Antelopes [Oryx beatrix), presented by 

 Colonel E. C. Ross, Consul-General for the Persian Gulf.— Mr. 

 Sclater exhibited and made remarks on two young specimens of 

 Darwin's Rhea {Rhea danvinii), obtained by Mr. A. A. Lane in 

 the province of Tarapaca, Northern Chili, and forwarded to Mr. 

 H. H. James. — Mr. Sclater exhibited and made remarks on a 

 flat skin of a Zebra, received from Northern Somaliland, which 

 appeared to be referable to Grevy's Zebra {Equus grcvyi). — Mr. 

 A. D. Michael read a paper on a collection of non-parasitic 

 Aearina lately made in Algeria, where he had found the Acarina 

 less abundant than in England, and, indeed, almost absen t from- 

 the true southern vegetation. The species met with were not of 

 larger size than the British. The collection consisted almost 

 entirely of Oribatidse, and contained examples of 46 species be- 

 longing to 15 genera. Amongst them were 8 species new to 

 science, 27 were British, and the rest South European. Amongst 

 the new species were a remarkable new Cccculus, there being 

 previously only one known species of this curious genus, which 

 forms a separate family. There was also a new Notaspis, which 

 had not been found in Europe, but had been received from the 

 shores of Lake Winnipeg, in Canada. There were likewise 

 some very singular new species of the genus Damaus, and a 

 triple-clawed form of Nothrus anauniensis. — Mr. Frank E. 

 Beddard read a paper on the anatomy of the Fin-foot [{Podica 

 senegalensis). The paper dealt chiefly with the myology and 

 osteology of this doubtful form. The conclusion arrived at was 

 that it showed most resemblance to the Rails, but that in its 

 muscular anatomy it agreed in many particulars with the Grebes 

 and Divers. — Mr. O. Thomas read some notes on the specimens 

 of Mammals obtained by Dr. Emin Pasha, during his recent 

 journey through Eastern Africa, as exemplified in the specimens 

 contained in two collections presented to the British Museum^ 

 and the Zoological Society respectively. — Mr. G. A, Boulenger 

 read a paper containing the descriptions of two new species of the 

 Siluroid genus Arges, from South America. — A communication 

 was read from Mr. James Yate Johnson, containing descriptions- 

 of five new species of fishes from Madeira. 



Linnean Society, May 24. — Anniversary Meeting. — Mr. 

 W. Carruthers, F.R.S., President, in the chair. — The Treasurer 

 presented his Annual Report, duly audited ; and, the Secretary 

 having announced the elections and deaths of Fellows during the 

 past year, the President proceeded to deliver his annual address. 

 In this he dealt with the distribution of British plants both before- 

 and after the Glacial period, making special allusion to the dis- 

 coveries of Mr. Clement Reid amongst the vegetation of the- 

 Cromer Forest Bed, and showed that the forms which have 

 come down to us at the present day do not differ in any respect 

 from the same species found in the Glacial beds. — A vote of" 

 thanks was moved by Sir Joseph Hooker and seconded by Mr. 

 Stainton to the President for his excellent address, with s. 

 request that he should allow it to be printed, and carried 

 unanimously. — On a ballot taking place for new Members of 

 Council, the following were declared to be elected : — Dr. P. H. 

 Carpenter, Dr. J. W. Meiklejohn, Mr. E. B. Poulton, Mr. D. 

 Sharp, and Prof. C. Stewart. On a ballot taking place for 

 President and Officers, the following were declared to be 

 elected : — President : Prof. Charles Stewart. Secretaries : B. 

 D. Jackson and W. P. Sladen. Treasurer: Frank Crisp. — The 

 Linnean Society's gold medal for the year 1890 was then, 

 formally awarded and presented to Prof. Huxley for his 

 researches in zoology. 



Entomological Society, June 4. — The Right Hon. Lord* 

 Walsingham, F. R.S., President, in the chair. — The Secretar)- 

 exhibited, on behalf of Mr. J. Edwards, Norwich, two speci- 

 mens oi Ilybius subaneus, Er., and a single s-pec\menoi J^idessus 

 unistriatus, Schr. Mr. Champion alluded to the fact that the 

 only recorded British specimens of the first- mentioned beetle 

 had been taken many years ago at Peckham. Lord Walsing- 

 ham, in alluding to the exhibit, referred to the list of Norfolk 



