October 24, igoi 



NA TURE 



611 



appeal was circulated, signed by Joseph Henry and 

 others, suggestinij the purchase of the instruments. 

 Koenig was induced to leave them at the University of 

 Pennsylvania under promise of their being insured for 

 10,500 dollars and of a weekly account of the subscrip- 

 tion being sent to him. But after a long and vain 

 expectation of the weekly accounts, and the writing of 

 many unanswered letters, it became evident to Koenig 

 that things were going wrong. In June 1878 Mr. 

 Munzinger, who had undertaken to collect the funds, 

 announced to Koenig that he had remitted the whole 

 subscription to Prof. Barker, but on December 15, 1879, 

 Prof. Barker wrote : " Mr. M. has not yet turned over to 

 me the subscription for the acoustical collection." On 

 June 30, 1SS2, he again wrote: "With regard to your 

 collection, I have been entirely unable to complete the 

 subscription for its purchase." There remained nothing 

 for Dr. Koenig to do but to go over and remove the col- 

 lection. A portion of it was sold at some sacrifice to 

 the University of Toronto, the physical collection of 

 which it adorns ; while the rest was brought back to 

 Paris. The incident had the most unfortunate effect 

 on Dr. Koenig. It crippled his slender resources for 

 more than ten years, and it tended to sour his sensitive 

 temperament. He had in 1876 communicated to 

 PoggendorfTs Aniiak/i two papers, one on a tuning-fork 

 of variable pitch, the other upon the phenomena pro- 

 duced by the interference of two tones. This latter 

 paper is one of the undoubted classics of science. 

 Using the most splendid and perfect of all tone-pro- 

 ducers, the substantial steel tuning-forks of his own 

 design, he had for years been investigating the pheno- 

 mena of beats and the production of interference-tones. 

 .Applying the phenomena of beats every day in his work- 

 shop for the purpose of adjusting forks to their exact 

 pitch, he acquired a familiarity with the phenomena 

 such as no other experimenter could possibly attain. His 

 published research is a model of careful and accurate 

 observation. Helmholtz had given the well-known 

 theory that when two tones are sounded together 

 there are produced two other tones, known as 

 the difference-tone and the summation-tone, having 

 frequencies respectively corresponding to the difference 

 and the sum of the frequencies of the two fundamental 

 tones. Koenig, finding himself unable to confirm the 

 existence of these alleged tones, set to work to find out 

 what the actual facts were. He investigated both the 

 beats and the resultant tones. He found that primary 

 beats were not all of one kind ; that they could be ranged 

 in two sets, an inferior and a superior set. Of these the 

 inferior alone correspond to the difference of the fre- 

 quencies, and so correspond only in the first octave. 

 Outside the first octave neither set of beats corresponds 

 either to difference or to sum. He found that when with 

 higher forks resultant tones are produced they likewise 

 may be ranged in two sets, an inferior and a superior set, 

 the pitch of these resultant tones being always precisely 

 that calculated as for beats. These resultant tones are 

 never either summation-tonesor differencetones exceptfor 

 tones within the range of the lower half of the first octave 

 of relative pitch, within which limits alone they corre- 

 spond to the difference of the frequencies. Outside that 

 limit there are no difference-tones. Under no circum- 

 stance, when pure notes are used as the two funda- 

 tnentals is the alleged summation-tone heard. It is true 

 that Prof. Rucker has by the most refined optical appli- 

 ances demonstrated the objective existence of the summa- 

 tion-tone. But the source was a powerful siren 

 which notoriously generates an impure tone. Koenig's 

 statement of 18S2, "Je ne connais jusqu'i present 

 aucune experience par laquelle on pourrait prouver 

 avec quelque certitude I'existence de sons differentiels 

 et de sons d'addition," remains absolutely true to-day. 

 During the years that followed the unhappy incident of 



NO. 1669, VOL. 64] 



1876 Koenig continued his investigations. Amongst the 

 apparatus at Philadelphia was the first of his wave-sirens, 

 a novel instrument which for the first time enabled the 

 experimenter to build up synthetically a complex tone out 

 of harmonic constituents in such a way as to vary at 

 pleasure the phases of the component tones. He had 

 discovered that, contrary to the theory of Helmholtz;. 

 phase-difference does exercise a modifying effect upon 

 the timbre, and is physiologically observable. This 

 theme he developed in a memoir entitled " Bemerkungen 

 iiber die Klangfarbe," which was published in Wiede- 

 mann's An/mien, vol. xiv., in 18S1. For this research he 

 constructed a large new wave-siren on a different plan. 

 The same instrument enabled him to investigate the 

 properties of tones produced by a succession of irregular 

 waves. In 1SS2 he published, under the title of 

 " Quelques Experiences d'Acoustique,' a volume of 243. 

 pages resuming his experimental researches down to that 

 date. This volume is now very scarce : it is a veritable 

 treasury of careful and refined experimental investigation^ 

 Of these acoustical researches a summary was given by 

 the present writer in N.xturic some years ago. In 

 1890 Dr. Koenig brought over to London his large wave- 

 siren and a number of the larger tuning-forks, and him- 

 self demonstrated the principal points of his researches 

 before a meeting of the Physical Society. These instru- 

 ments were also shown at the Royal Institution in June 

 of the same year at a Friday evening discourse on the 

 physical basis of music. .\ few of the forks were acquired 

 for the National Collection at South Kensington. 



On recovering in the autumn of 1SS2 the unsold portiort 

 of his acoustical collection, he proceeded to reconstruct, 

 on a larger scale than before, the great tonometer, the 

 series of standard tuning-forks which originally extended 

 in unbroken series only from the frequency of 12S to that 

 of 4096 vibrations. He added massive steel forks, some 

 of them weighing nearly 200 pounds, taking the frequency 

 down to 16, while at the higher end of the scale he added 

 several octaves, so that eventually he reached a pitch 

 above the superior limits of ordinary audition. One of 

 his latest researches was, indeed, upon the verification, 

 by the method of Kundt of the wave-length of these 

 inaudible forks, going up to 45,000 vibrations per second. 

 This splendid set of standard instruments has remained 

 until now in Dr. Koenig's ati'lier. An attempt was made 

 about three years ago--unfortunately without success — 

 to secure it for the National Collection of Scientific Ap- 

 paratus at Kensington. It can never be duplicated, and 

 its dispersal would be a misfortune for science. 



Dr. Koenig suffered during his last years from much 

 broken health. He never married, but lived alone, sur- 

 rounded by the instruments of his creation, in his work- 

 shop on the Quai d'.Anjou. Here he received from time 

 to time the visits of his friends. The late Mr. Spottis- 

 woode used frequently when passing through Paris to 

 visit him. A brief word of announcement that one would 

 give oneself the pleasure of calling next Sunday morn- 

 ing always found Koenig ready and pleased to spend an 

 hour in showing his latest experiments. The last time 

 that I had this opportunity was during the Electrical 

 Congress in September 1900. He had during the pre- 

 ceding week had a similar visit from Lord Kelvin. 

 Koenig was even then very ill. He suffered terribly in 

 body and was obviously feeble. For some months he 

 had lived on nothing but milk. But he was as animated 

 and keen as ever. He had some new observations and 

 a new instrument — no account of which has been pub- 

 lished — demonstrating the influence of phase upon the 

 quality of compound tones. They were simple and con- 

 vincing. But the occasion was mournful ; his bodily 

 sufferings were only too evident. He wrote me in the 

 spring of the present year that his health was still inore 

 precarious. He died on October 2, 1901, aged sixty-eight 

 years. 



