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Changes of refrangibility in electric spectra
262
Theory of the Steam Engine.
[Jour. Frank. Inst.~
to the Steam E n g i n e and to the P h y s i c a l Properties of Bodies. E d i t e d by Professor Hirst). L o n d o n : 1867. Same. T r a n s l a t e d b y W a l t e r R. Browne. L o n d o n : 1879. Hirn~ G . A . Thermodynamlque. Paris: 1876-7. Cotterill~ J . H . T h e Steam E n g i n e Considered as a H e a t E n g i n e . L o n d o n : 1878. Thurston~ R . H . H i s t o r y of the Steam E n g i n e . (International Series). ~ e w Y o r k a n d London~ P a r i s and Leipzie : 1878. Same. Curves of Efficiency. J o u r n a ] F r a n k l i n I n s t i t u t e . F e b . 1882. Thomson~ S i r W m . Mathematical and Physical Papers. C a m b r i d g e : 1882.
C~IAINGES OF t~EFI4ANGIBILITY IN ELECTRIC ~PECTRA.---It is well k n o w n that the hydrogen lines, i n the spectra of solar spots and protuberances, are often suddenly displaced, so as to appear wavy or broken. This is especially the case with the C line. The velocities impressed upon the gaseous particles must be so enormous that there seemed little likelihood of reproducing the phenomena i n the labratory. Cazin supposed t h a t electricity m i g h t have sufficient velocity, but he felt the need of n e w investigations in that direction. Liveing and Dewar lbund that when a few drops of water were injected into the voltaic arc, there was a sudden enlargement of the hydrogen lines, quite comparable to that which is often observed i n the solar atmosphere and attributed to eruptions. Fievey found similar phenomena, by passing a series of electric sparks betweei~ electrodes of magnesium which were only one or two millimetres apart, i n a tube of three centimetres diameter, which was filled with hydrogen u n d e r a mercurial pressure of two metres. I-Ie employed a Christie spectroscope which gave, with a half prism, a dispersion equivalent to that of six flint prisms. The spark was furnished by a large coil, connected with a condenser and driven by a battery of ten hi-chromate of potassium elements. The electrodes were perpendicular to the slit, which was so regulated as to give the sodium lines with sharp definition. A n objective was interposed between the electrodes and the slit. Under these circumstances the C hydrogen line and the m a g n e s i u m lines b~7 bz and b3 undulated, expanded and broke on the right and on the left.--/~u/~, de PAcad..Belg. 1884. C.
SUNSETS IN C~INA.--Dechevrens, the director of the Observatory at Zi-k~e-wei, reports that the brilliant twilights and the green sun were observed i n Chin G as well as i n Europe, during the last a u t m n n . On the other hand, during the winter, the zodiacal light appeared to h i m fainter t h a n on preceding years. This corresponds with the testimony of Thollon and Perrotin at Nice, and of Janssen~ at Meudon.--Les Mondes, April 18, 1884, C.
Theory of the Steam Engine.
[Jour. Frank. Inst.~
to the Steam E n g i n e and to the P h y s i c a l Properties of Bodies. E d i t e d by Professor Hirst). L o n d o n : 1867. Same. T r a n s l a t e d b y W a l t e r R. Browne. L o n d o n : 1879. Hirn~ G . A . Thermodynamlque. Paris: 1876-7. Cotterill~ J . H . T h e Steam E n g i n e Considered as a H e a t E n g i n e . L o n d o n : 1878. Thurston~ R . H . H i s t o r y of the Steam E n g i n e . (International Series). ~ e w Y o r k a n d London~ P a r i s and Leipzie : 1878. Same. Curves of Efficiency. J o u r n a ] F r a n k l i n I n s t i t u t e . F e b . 1882. Thomson~ S i r W m . Mathematical and Physical Papers. C a m b r i d g e : 1882.
C~IAINGES OF t~EFI4ANGIBILITY IN ELECTRIC ~PECTRA.---It is well k n o w n that the hydrogen lines, i n the spectra of solar spots and protuberances, are often suddenly displaced, so as to appear wavy or broken. This is especially the case with the C line. The velocities impressed upon the gaseous particles must be so enormous that there seemed little likelihood of reproducing the phenomena i n the labratory. Cazin supposed t h a t electricity m i g h t have sufficient velocity, but he felt the need of n e w investigations in that direction. Liveing and Dewar lbund that when a few drops of water were injected into the voltaic arc, there was a sudden enlargement of the hydrogen lines, quite comparable to that which is often observed i n the solar atmosphere and attributed to eruptions. Fievey found similar phenomena, by passing a series of electric sparks betweei~ electrodes of magnesium which were only one or two millimetres apart, i n a tube of three centimetres diameter, which was filled with hydrogen u n d e r a mercurial pressure of two metres. I-Ie employed a Christie spectroscope which gave, with a half prism, a dispersion equivalent to that of six flint prisms. The spark was furnished by a large coil, connected with a condenser and driven by a battery of ten hi-chromate of potassium elements. The electrodes were perpendicular to the slit, which was so regulated as to give the sodium lines with sharp definition. A n objective was interposed between the electrodes and the slit. Under these circumstances the C hydrogen line and the m a g n e s i u m lines b~7 bz and b3 undulated, expanded and broke on the right and on the left.--/~u/~, de PAcad..Belg. 1884. C.
SUNSETS IN C~INA.--Dechevrens, the director of the Observatory at Zi-k~e-wei, reports that the brilliant twilights and the green sun were observed i n Chin G as well as i n Europe, during the last a u t m n n . On the other hand, during the winter, the zodiacal light appeared to h i m fainter t h a n on preceding years. This corresponds with the testimony of Thollon and Perrotin at Nice, and of Janssen~ at Meudon.--Les Mondes, April 18, 1884, C.