682' 



METEOROLOGY. 



ated haze, there is formed an extensive stra- 

 tum of air at considerably higher tempera- 

 ture." His paper on this subject contains a 

 series of comparisons tending to show that the 

 conditions under which his artificial glows were 

 produced have actually existed whenever the 

 remarkable sunset effects have made them- 

 selves prominent. 



The phenomenon known as Bishop's Ring, 

 which was first noticed in the latter months of 

 1883, is supposed to have the same origin as 

 the red sun-glows described in the " Annual 

 Cyclopaedia" for 1883. It may be described 

 as a corona of dusky, coppery, or reddish light 

 surrounding the sun and visible at noonday. 

 The circle of most distinct color has a radius 

 of about 15, and incloses a brilliant silvery or 

 bluish glow close around the solar disk. As 

 described by Dr. Kremser, who observed it 

 from the Schneekoppe, in Prussia, " in remark- 

 able completeness," in January, 1885, the space 

 for about 10 around the sun was of a brilliant 

 white, and this passed through yellow and yel- 

 low-brown into the copper-colored ring, 6^ 

 broad. At the point where it touched the 

 horizon, the two limbs showed different tints. 

 The ring was plainly to be seen on clear days 

 during the winter of 1884-'85, and during the 

 latter months of 1885 ; but the hazy days of 

 summer are not favorable to its visibility. It 

 is best seen from elevated stations. The nu- 

 merous observations of the phenomenon in 

 Europe and America all point to the conclu- 

 sions that it is produced in the upper atmos- 

 sphere, and that it was continuously present 

 above the cloudy or dusty lower air over a 

 large part if not over the whole of the earth 

 throughout 1884 and 1885. It is explained as 

 a relatively simple effect of diffraction, of the 

 same nature as that which is seen in the col- 

 ored rings surrounding a light looked at through 

 a faintly frosted glass. Colored coronal rings 

 may be seen also around a light when looked 

 at through a glass strewed lightly over with 

 spores of lycopodium. Kiessling's experiments 

 with thin artificial clouds, through which the 

 sun appears surrounded with coronal rings, are 

 of similar character. The moon is often sur- 

 rounded with similar rings of small diameter, 

 probably on small floating particles of ice. 

 These rings are different from halos, which are 

 of definite and much larger diameter, and are, 

 when seen around the moon, generally whitish ; 

 when formed around the sun, visibly colored 

 with red inside. The first recorded observa- 

 tion of the new corona was made by the Rev. 

 Sereno F. Bishop, after whom it is named, at 

 Honolulu, Hawaii, on Sept. 5, 1883. It was 

 first seen in the United States by Prof. John 

 Le Conte, at Berkeley, Cal., on the 24th of 

 November of the same year; and in Europe 

 on the days following. The near coincidence 

 of these dates of observations with those on 

 which the red sunsets were first noticed in the 

 same regions suggests a community of origin 

 for the two phenomena; and the recognized 



fact that both could be produced by a sufficient 

 supply of extremely fine solid or liquid dust 

 scattered through the atmosphere points to 

 the same conclusion, and tends to corroborate 

 the theory that ascribes them to the volcanic 

 dust of Krakatoa. The objections to the the- 

 ory, based upon the quantity of dust that would 

 be required to produce them, and the difficulty 

 of conceiving it to remain afloat so long, are 

 not insurmountable. Experiments by Tyndall 

 suggest that the quantity of dust may really be 

 insignificant in proportion to the mass of the 

 atmosphere; and, given dust of the extreme 

 tenuity that volcanic ashes are known to be, 

 they would evidently be a very long time in 

 settling. The action of these particles of dust, 

 if such they be, would, moreover, be re-en- 

 forced by the office they are known to perform 

 of serving as nuclei for the condensation of 

 aqueous vapor, by which their diffraction-ef- 

 fects would be increased. We have, therefore, 

 still liberty to believe that the intense red sun- 

 sets of 1883-'84 were caused primarily by the 

 injection into the air of immense masses of 

 dust and vapor from Krakatoa; that their 

 gradual diminution corresponded with the 

 slow settling down of the particles ; until, at 

 length, the brilliancy of the display has been 

 lost, and the moderate residual of the dusts and 

 vapors produces nothing more than a fainter 

 colored ring and sunset glows that are visible 

 only under especially favorable circumstances. 

 The United States Signal-Office has compiled 

 a series of charts showing the relative fre- 

 quency of storms for each month and for the 

 year, in that part of the northern hemisphere 

 for which the data are available. They are tnt 

 results of observations extending through ont 

 hundred and thirty-four months, from 1863 tc 

 1883. For the whole year, the region where 

 storms occur with greatest frequency is a belt 

 of about two hundred miles in width, extend- 

 ing from the head- waters of Red river, about 

 95 west longitude, eastward through the Great 

 Lakes to the mouth of the St. Lawrence, about 

 70 west longitude. Surrounding this is a 

 more extensive region where the number of 

 storms, though not so large, is still a good way 

 over the average ; and again, surrounding this 

 latter, is a still wider region, stretching from 

 105 west longitude eastward through the 

 States and Canada, and through the Atlantic 

 as far as 20 west longitude. This is one of 

 the most important regions of the globe as re- 

 gards storms or cyclones. Another region of 

 considerable storm frequency extends from the 

 south of Greenland, through Iceland and Faroe, 

 to the north of Sweden. This distribution pre- 

 vails particularly during the cold months, whe 

 the larger number of storms occur. In tl 

 spring and summer months the distribution is 

 materially altered. Thus, in April the regioi 

 of greater frequency extend farther south wai 

 in the United States and the Atlantic. ' 

 southing of the tracks of the cyclones is stil 

 more distinctly marked in Europe. It is shown 



