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INDEX. 



Sen (1ST. K.) on the potentials of 

 elliptic cylinders, 465. 



Siegbahn (Dr. M.) on precision-mea- 

 surements in the X-ray spectra, 

 639,647. 



Silberstein (Dr. L.) on non-metrical 

 vector algebra, 115; on a time- 

 scale independent of space mea- 

 surement, 382. 



Silver oun, on the value of the, 301. 



Slade (Dr. R. E.) on the law for the 

 true photographic rendering of 

 contrast, 187, 637. 



Slip-curves of an Amsler plani- 

 meter, on the, 489. 



Soddy (Prof. F.) on the relation 

 between uranium and radium, 483. 



Sodium, on the optical properties 

 of films of, 98. 



Solution, on the molecular theory 

 of, 696. 



Sommerville (Dr. D. M. Y.) on the 

 slip-curves of an Amsler plani- 

 meter, 489. 



Spark discharge, time-lag in the. 

 214. 



Spectrograph, on an X - ray, for 

 medium wave-lengths, 647 ; on a 

 positive ray, 707. 



Spectrum, on the series system in 

 the, of gold, 245 ; on four tran- 

 sition points in the, and the 

 primary colour sensations, 55. 



Stability, on the Clifford function 

 in problems of, 501. 



Stream-line flow from a disturbed 

 area, on, 433. 



Stresses, on the equations for 

 material, 235. 



Stringed instruments, on the partial 

 tones of bowed, 573. 



Surface energy, on latent heat and, 

 240. 



tension and chemical inter- 

 action, on, 417. 



Terrestrial refraction, on, 546. 



Time-lag in the spark discharge, 

 on, 214. 



— -scale independent of space 



measurement, on a, 382, 652. 



Thermal conductivity, on the, of 

 solid insulators, 705. 



Thornton (Prof. TV. M.) on the 



ignition of gases by hot wires, 



613; on the thermal conductivity 



of solid insulators, 705. 

 Todd (Prof. GV.W.) on the Kundsen 



vacuum gauge, 381 ; on a vapour 



pressure equation, 655. 

 Trechmann (Dr.C. T.) on interglacial 



loess in Durham, 425. 

 Tungsten, on the X-ray spectrum 



of/ 639. 

 Uranium and radium, on the relation 



between, 483. 

 Vacuum gauge, on the theory of the 



Knudsen, 381. 

 Vapour pressure equation, on a, 655. 

 Vector algebra, on a non-metrical, 



115. 

 Vibration of floors and critical speeds 



of machinery, on, 395 ; on the 



magnetic effects of, 528. 

 Violin family of instruments, on the 



partial tones of the, 573. 

 Viscosity, coefficients of, of hydrogen, 



nitrogen, and oxygen, 582. 

 Vision, on 'the persistence of, of 



colours, 81. 

 Vortex, on the mass carried forward 



by a, 597. 

 Water, on the rate of solution of 



nitrogen and oxygen by, 317. 

 Waves, on electromagnetic, 90, 143 ; 



on the propagation of electro- 

 magnetic, round the earth, 365. 

 Whitaker (W.) on the section at 



Worms Heath, 668. 

 Wires, on the ignition of s^ses bv 



hot, 613. 

 Wood (Prof. W.) on the optical 



properties of films of sodium and 



potassium, 98. 

 Worth (E. H.) on the geology of 



the Meldon Valleys, 267. 

 "Wrinch (Miss D.) on some aspects 



of the theory of probability, 715. 

 X-ray spectrum of tungsten, on the, 



639. 

 Yen (Prof. Kia-Lok) on the co- 

 efficients of viscosity of hydrogen, 



nitrogen, and oxygen, 582. 

 Young (Dr. F. B.) on the magnetic 



eeffcts of vibration, 528. 



END OF THE THIRTY-EIGHTH VOLUME. 



Printed by Taylor and Francis, "Red Lion Court, Fleet Street. 



