THE CLOUD BURSTS IN NEVADA. 51 



touched the outer circle which surrounded the sun. There were traces of 

 other arcs of circles, but none which were very distinct. The primary or 

 inner circle around the sun was at a distance of twenty-two degrees, con- 

 sequently had a diameter of forty-four degrees. The outer circle was at a 

 distance of forty-five degrees, or had a diameter of ninety degrees. 



The circle whose centre was in the zenith had a diameter of thirty-six 

 degrees — eight degrees less than that nearest the sun. This circle, or rather 

 arc of a circle, as also the entire circle next the sun, were very brightly 

 tinted with the prismatic colors; red occuj^ying the centre of the luminous 

 circle, indigo and violet the outer part, shading away by insensible degrees 

 till they were blended with the general color of the sky. The color of the 

 sky inside of the principal circle was an intense dark blue, sometimes 

 beautifully flecked with white clouds, while the space inside the zenith 

 circle was even of a darker blue, and at times almost black, with j)ui'plish 

 tinge. 



The most satisfactory explanation of this curious but rare phenomenon 

 is to attribute it to the refraction and reflection of light, due to a peculiar 

 state of the atmosjjhere. When the moisture of the atmosjjhere congeals 

 into snow or frost, it assumes various crystalline forms. Under certain cir- 

 cumstances the form of these crystals is such that the faces are inclined to 

 each other in an angle of sixty degress. A ray of light passing through a 

 ci'ystal of ice of this form would be refracted from a straight line at an 

 angle of twenty-two degrees. To the eye of an observer, therefore, the 

 halo would appear at a distance from the sun equal to twenty-two degrees. 

 This theory is also an explanation of the order in which the colors occur. 

 The ratio of refraction of the violet ray being greater than the red, the 

 former would occupy the part of the halo farthest from the sun. The sec- 

 ondary halos and jsarhelia are probably the result partly of reflection and 

 partly of double refraction. 



Similar phenomena have been described by Aristotle, Pliny, Scheiner, 

 Descartes and others, the best description being that of Hevelius, as ob- 

 served by him at Dantzic on the 20th of February, 1661. Parhelia very 

 seldom remain visible more than two hours. That of the 23d inst. was of 

 longer duration tlmn any heretofore recorded, being distinctly visible for 

 over five hours. — Boulder News. 



In connection with some electric exiDeriments elucidatory of the phe- 

 nomena of the auroras, Plante states that one might conclude that the 

 aurora results from the diffusion in the upper strata of the atmosphere 

 around the magnetic poles of the positive electricity emanating from the 

 polar regions themselves ; which emanations may take place either ob- 

 scurely, when no obstacle is interposed, or may take place visibly, as auroral 

 light, by meeting with aqueous masses either in the solid or liquid state; 

 which matter is vaporized by the heat evolved in the electric discharge, 

 and is subsequently again precipitated either as rain or snow at the surface 

 of the globe. 



THE CLOUD BURSTS IN NEVADA. 



The San Francisco Bulletin says : "Nevada has again been visited with 

 the meteorologic phenomena of cloud-bursts. Heavy rains prevailed all over 

 Nevada, but the cloud-bursts, as two years ago, seem to have been confined 

 to the eastern portion of the State. The recent calamity near Eureka has 

 been the more destructive, and it is a little singular that the phenomenon 

 should have occurred within a few minutes of the same time as that which, 

 two years ago, on the same day of the month, caused such a large destruc- 



