3o6 



NATURE 



[November 14, 1912 



Gramophone Experiments. 



For some time I have been experimenting with the 

 gramophone sound-box, and I eame to the conclusion 

 that with a diaphragm nipped firmly between two 

 rubber rings there was a tendency for a vibration 

 from the stylus bar to be cannoned back from the 

 edge so held, and that one did not get a true ring. I 

 made a sound-box as shown below (Figs, i and 2) in 



^^/ 



Tz^.2. 



Figs. 1 and 2. — a is half a split ring connected to the sound box /' ; c is the 

 other half of the split ring connected to a by screws d d ; the diaphragm 

 e is held in position by an elastic ringy^ which is secured to sound box 

 by means of the two halves a and c\ g\i the stylus bar. The sound box 

 is protected by patent. 



which the diaphragm is only held on its edge, and 

 by cutting the front of the box in half it enabled me 

 to mount the diaphragm free from distortion. With 

 this box there is a very marked difference. 



In a band record one can differentiate each instru- 

 ment more readilv. 



Working on Prof. McKendrick's experiments, as 

 described in Nature of April 20, 191 1, I found that 

 with an enclosed horn machine, as shown in Figs. 3 

 and 4, by passing the sound waves through about 

 17 ft. of 2-in. flexible metallic voice tube (the tubes 

 all being inside the cabinet out of sight), all the 



NO. 2246, VOL. 90] 



noises which he eliminates by the use of peas are done 

 away with, and the sound much increased by not 

 using peas. In addition to this, to augment the sound 

 I place a 2 ft. by 8 in. deep conical reflector with the 

 apex of the cone cut off, leaving a 4-in. opening 

 pointing to horn, as shown in Fig. 4. The result is 

 that a musical effect is produced free from overtones 

 and harsh sounds. Ernest de \,\ Rue. 



With reference to the above interesting communica- 

 tion b\' Mr. Ernest de la Rue, I have to say that the 

 method he has adopted for fixing the diaphragm of the 

 sound-bo.x is a marked improvement. Mr. de la Rue 

 has kindly sent me a specimen of the sound-box, and 

 it has given me great satisfaction, both as to qualitv 

 and volume of tone. I have not had the opportunity 

 of hearing the arrangement he has devised lor remov- 

 ing friction noises, but no doubt it will be satisfactory. 

 1 am quite pleased with my own method, which gives 

 excellent results, and it is adapted to the older form 

 of gramophone which I use. The tones are sufficiently 

 loud for a room of ordinary dimensions, and the 

 quality, with Mr. de la Rue's sound-box, is excellent. 

 .4 witty friend of mine has called my plan the pipe of 

 peace (peas) I J. G. McKendrick. 



Reported Occurrence of the Dartford Warbler at the 

 Tuskar Light Station. 



I H.'iVE recently returned after nine weeks' residence 

 at the Tuskar Light Station, off the south-east coast 

 of county Wexford, where I have been prosecuting 

 the study of bird-migration. I obtained several in- 

 teresting records, including those of some rare species. 

 To these may be added a highly interesting and at 

 the same time important record of the occurrence of a 

 Dartford warbler. Owing to the sedentary habits of 

 this species its appearance at the Tuskar Rock was 

 quite unexpected, and heretofore the bird was un- 

 known in Ireland. 



This warbler was obtained on October 27, as I am 

 informed by the principal lightkeeper, to whom I owe 

 my cordial thanks for the kind aid he has so often 

 and cheerfullv given me in connection with my work 

 on bird-migration. C. J. P.4TTEN. 



The University, Sheflield, November 10. 



THE CRYSTAL SPACE-LATTICE 

 REVEALED BY RONTGEN RAYS. 

 TOURING a visit to Munich at the beginning of 

 J-^ August last the writer was deeply interested 

 in some extraordinary photographs which were 

 shown to him by Prof, von Groth, the doyen of 

 the crystallographic world, and professor of 

 mineralogy at the university of that city. They 

 had been obtained by Dr. M. Laue, assisted in the 

 experiments by Herren W. Friedrich and P. Knip- 

 ping, in the laboratory of Prof. A. Sommerfeld in 

 Munich, by passing a narrow cylindrical beam of 

 Rontgen rays through a crystal of zinc blende, 

 the cubic form of naturally occurring sulphide of 

 zinc, and receiving the transmitted rays upon a 

 photographic plate. They consisted of black 

 spots arranged in a geometrical pattern, in which 

 a square predominated, exactly in accordance with 

 the holohedral cubic symmetry of the space- 

 lattice attributed by crystallographers to zinc 

 blende. 



Prof, von Groth expressed the opinion, in agree- 

 ment with Hcrr I.auc, that owing to the exceed- 



