376 SCIENTIFIC RECORD FOR 1884. 



and assigns to the various groups of atmospheric lines corresponding 

 metallic lines for comparison. {Z. 0. G. M., xviii, p. 239.) 



377. Dr. H. Klein, in reference to the use of the spectroscope, or the 

 observation of the so-called rain band, states that his own observations 

 confirm those of Smyth, Capron, and others to the effect that a promi- 

 nent rain band is regularly followed in a short time by precipitation. 

 However, the frequent exceptions to this rule renders the spectroscope 

 alone very unreliable; this is to be attributed to the fact that the spec- 

 troscope makes no distinction between the moisture near by and that at a 

 great distance. When from his observatory Klein examines tbe horizon 

 at an altitude of 20°, he finds the vapor lines on the east, southeast, and 

 noitheast notably darker and more prominent than in any other direc- 

 tion; this be attributes to the fact that a few thousand feet distant on 

 the east flows the broad Ehine; but he states that this increase of the 

 vapor line does not always occur, and at certain times the influence of 

 the Ehine is not to be noticed; he has as yet found no explanation for 

 these exceptional cases. The application of the spectroscope to the 

 prediction of rain is, he thinks, jiroblematic, except in the case of heavy 

 thunder storms for which it frequently gives good indications. Upton's 

 comparison showed that G9 per cent, of rain predictions were verified 

 within twenty-four hours when based entirely upon the intensity of the 

 rain band, but 84 per cent, were verified when other meteorological con- 

 ditions were taken into account. The spectroscope has been used at 

 the Wetterwarte of the Cologne Zeitung with satisfactory results in 

 summer. {Z. 0. G. i¥., xix, p. 531.) 



378. Mr. W. Ackroyd has read before the Physical Society of London 

 a mathematical investigation of the rainbows produced by light before 

 entering the rain drops. {Nature^ xxvii, p. 133.) 



379. The observation of coronas and fogbows, made at the summit of 

 Ben Nevis, promises to give us valuable information in regard to the size 

 and shape of the particles composing the clouds ; thus, October 4, 1884, 

 strong double corona surrounded the moon; outer diameter of the red 

 circle was for the outer corona 7° 46', and for the inner corona 4° 52'. 

 When clouds came between the moon and observer three such rings 

 were seen, the measurements of which gave for the inner ring 4° 6', 

 middle 0° 2', outer 8° 10', the probable error in each ring being about 

 8'. A colorless pair of fogbows visible on a distant fog bank gave 

 diameters of 75'^ for the outer ring, 65° for the inner and fainter ring; 

 the space between the ring appeared quite dark and no color could be 

 distinguished. {Nature, xxx, p. 613.) 



380. Professor von Bezold, in the publications of the International 

 Polar Commission, described the normal phenomena of twilight as fol- 

 lows : 



1. A bright segment appears on that side of the sky below whose 

 horizon the sun is found ; this is limited at the top by a special bright 



