176 



SCIENCE. 



[N. S. Vol. XVI. No. 396. 



the center of each strip opposite a small 

 vane. The whole system is placed in a 

 bell- jar in svieh a way that the strips are in 

 the focus of a parabolic mirror. The de- 

 flections are read by a telescope and scale. 

 Owing to the lightness of the moving sys- 

 tem (abont 6.5 mgs.) and the efficiency of 

 the method, the sensitiveness can be made 

 much greater than that of the receivers of 

 the Klemencic design. 



On the Efficiency of Window Illuminating 



Prisms: D. C. Miller, Case School of 



Applied Science. 



The paper gave the results of photo- 

 metric investigation of the distribution of 

 light by prisms of various shapes, placed 

 in dift'erent positions and operating with 

 various sky conditions. The results are 

 shown by distribution diagrams, from 

 which are drawn concliisions as to the rel- 

 ative efficiencies under given conditions. 

 A Portable Photometer for Measuring 



Light Distrihution: D. C. Miller, Case 



School of Applied Science. 



The ari-angement described is a special 

 form of photometer which may be moved in 

 any way, as about a pivot, for quickly meas- 

 uring with moderate accuracy the relative 

 intensity of light sent out in any direction 

 from a source. 



A Luramer-Brodhun screen is used to 

 compare the light from the source with 

 that from a standard illumination, the lat- 

 ter being capable of measured regulation 

 from zero intensity to the maximum re- 

 quired. 



The application of the photometer to the 

 measurement of the distribution of light 

 throughout a room, as by a window prism, 

 was described. 

 Models for Explaining Polarized Ligh t : D. 



C. jMillee, Case School of Applied 



Science. 



A description (with exhibit) was given 

 of a series of original models for explain- 



ing double refraction, action of one Nicol 

 prism and of two Nicols forming a polari- 

 seope ; also for explaining the production of 

 interference colors by a thin plate of a 

 doubly refracting substance placed between 

 crossed polarizer and analyzer. 



A Model for 8howi)ig the Superposition of 



Two Oppositely Moving Wave-trains: 



W. S. Franklin, Lehigh University. 



This model is designed for class-room 



demonstration and it consists of a large 



number of horizontal bars. One set of ends 



of these bars rests upon a wave-template 



and the other set of ends rests upon another 



Avave-template. These two templates move 



in opposite directions at the same velocity. 



The middle points of the horizontal bars 



communicate to a row of points or balls the 



resultant motion of the two wave-trains. 



Tlie Just-Intonation Pianoforte of Dr. S. 



A. Hageman: H. T. Eddy, University of 



Minnesota. 



Dr. Hageman has invented and con- 

 structed a pianoforte which will render the 

 diatonic scale in perfectly just intonation 

 in any key that may be desired. The piano 

 dift'ers in outward appearance from the 

 ordinarj-- piano simply in the fact that there 

 is, in addition to the usual pedals, a bank of 

 a single octave of pedals somewhat like 

 organ pedals. These pedals actuate a bank 

 of sliding bars on the back of the piano, 

 which, in turn, move the bridges on which 

 the piano strings rest, and adjust them 

 simultaneously to any kej^ desired bj'- thus 

 altering their effective lengths. It is be- 

 lieved that this cheap and exceedingly 

 simple but perfectly effective device is the 

 first practical solution of the problem of 

 just intonation for instriunents \vith fixed 

 Iteys. The device is applicable to other 

 instruments with fixed keys. 



The piano is tuned in the usual manner 

 in equal temperament and may be plaj-ed 

 in equal temperament also if so desired. 



