June 19, 1896.] 



SCIENCE. 



901 



ture by environment and on heredity. Fo 

 example, we might expect increased webbing 

 of the feet, and this might become hereditary. 

 HiEAM M. Stanley. 

 Lake Forest, III., June. 



DAKKENING OF THE CATHODE IN A 

 CEOOKES TUBE. 



A PEAE-SHAPED Crookes tube with a cathode 

 disc in its narrow end has been used extensively 

 by us during the past ten weeks in private ex- 

 perimentation and in public lectures on Rontgen 

 rays. In common with many other experi- 

 menters, we have observed that after much 

 usage the glass opposite the cathode disc and 

 the glass about the anode became darkened. 

 But we do not recall having seen any statement 

 recorded regarding the darkening of the ca- 

 thode disc. When we began using the tube 

 the surface of the aluminium disc was uni- 

 formly bright throughout ; now there is on the 

 surface facing the broad end of the tube a dark 

 brown ring concentric with the disc. This ring 

 has an internal diameter of about 6 mm., and 

 is darkest near its inner edge, the densest por- 

 tion being, perhaps, 1 mm. across. Outside of 

 this darkest portion the ring fades ofi" gradually 

 toward the outer edge of the disc. Taken as a 

 whole, the internal and external diameters of 

 the ring are about 5 mm. and 11 mm. respec- 

 tively. The circular area inside of the dark 

 ring is the brightest part of the disc. The 

 diameter of the disc is about 17 mm. 



During the discharge through the tube we 

 now observe what we did not notice before, 

 viz., a pencil of faint bluish light emanating 

 from the circular area of the disc inside the dark 

 ring. The pencil is normal to the disc. The 

 light resembles the blue or purplish light about 

 the anode. The cylindrical pencil is most dis- 

 tinct at the disc and gradually fades away and 

 becomes invisible at a distance from it of about 

 2 or 3 cm. If, by reversal of the current, the 

 disc is made the anode, then the pencil of blue 

 light cannot be seen, but almost the entire tube 

 is iilled with the same purplish light. Some- 

 times this purplish light fills the tube also when 

 the disc is used as a cathode. In such cases 

 the discharge at the spark gap (placed in series 

 with the tube) is fat and noisy ; the tube shows 



very little fluorescence and the radiation of 



Eontgen rays is greatly diminished. 



Floeian Cajobi, 

 William Strieby, 

 Coloeado College, Colorado Springs. 



SCIENTIFIC LITERATURE. 

 Voice Building and Tone Placing, showing ai 



method of relieving injured vocal cords by 



tone exercises. By H. Holbeook Curtis, 



Ph. B., M. D. D. Appleton and Company.. 



1896. 



This latest claimant for favor in the diificult 

 field of voice production will be found to con- 

 tain much that is old to those familiar with the- 

 subject of acoustics and some that is as unex- 

 pected as it is new. The struggling pupil will 

 find it difficult to extract the pearl of good ad- 

 vice from the shell of lengthy discussion. 

 From the preface one can see that the author 

 realizes at once the difficulty of the problem and 

 what its solution should be, but it is doubtful 

 if he has fulfilled the promise. 



The author begins with a brief outline of the- 

 history of music, which is followed by a de- 

 scription of the anatomy of the larynx which is 

 naturally all right, until he begins to discuss- 

 the operation of the various parts, and here cer- 

 tain discrepancies arise. For example, we are 

 told that there is but one register, or rather 

 that registers are ' fallacies,' and yet in attempt- 

 ing to discuss our control of pitch he refers to 

 reaching a ' stage in the production of th& 

 lower register,' where, 'for any other further 

 elevation of pitch, a complete rearrangement of 

 the vocal apparatus is necessary.' Just exactly 

 what the devotees of registers claim. In point of 

 fact, however, if one has the proper use of the 

 voice, the same muscles control the pitch from 

 lowest to highest, without break or interruption. 



The above is an example of the uncertainty 

 in which the reader is left; registers are called 

 fallacies, and yet they are discussed at length -^ 

 they are assumed to exist and their fundamen- 

 tal differences in mechanism pointed out. 

 Another statement which is very misleading, to 

 say the least, is that air pressure in the lungs 

 aflTects the pitch of the tone ; ' ' the pitch of the 

 tone depends upon the strength of the expira- 

 tory pressure. ' ' How can we then take a tone 



