August 29, 1889] 



NATURE 



415 



LETTERS TO THE EDITOR. 



( The Editor does not hold himself responsible for opinions ex- 

 pressed by his correspondents. Neither can he utidertakt 

 to return, or to correspond with the writers of, rejected 

 manuscripts intended for this or any other part of Nature. 

 No notice is taken of anonymous communications. ] 



Sunset Glows at Honolulu. 



There has just been at Honolulu a reappearance of the 

 phenomenon' of sunset glows like those so familiar in 1883-84. 

 It was first noticed after sundown of July 13. It seemed sone- 

 what brighter on the 14th and 15th. After this it declined in 

 intensity, but could be distinguished until the 20th. 



A space of 15° radius around the sun was occupied by a whitish 

 glow like that in "Bishop's ring." The outer coloured ring 

 seemed to be entirely wanting. 



We have no cable, and no foreign mail has arrived since the 

 6th. By a mail due to-morrow, we hope to hear of a probable 

 cause to which this remarkable appearance may be due. 



I note the following differences between these sunset glows 

 and those of 1883-84. These are very much less bright than 

 those ; possibly equal to what those became after one year's con- 

 tinuance. Perhaps the most notable difference is the appearance 

 of a tertiary glow after the primary and secondary. This con- 

 sisted of a delicate rosy flush occupying a large tract of sky above 

 the western horizon, from the altitude of 10° to that of 45°, and 

 about 60° horizontally. This shaded off into purple at the edges 

 against our clear blue Hawaiian sky. I think this the most ex- 

 quisite and lovely tint I have ever seen in the sky, comparable 

 only to that of some perfect jewel. 



The larger stars were visible at the time of this tertiary glow. 

 It continued for only a very few minutes each evening. A faint 

 purple tint extended along the horizon quite to the south. This 

 third glow failed to gather down upon the horizon like those 

 preceding it. 



Another marked peculiarity is the much earlier time at which 

 the primary and secondary take place. The primary glow 

 gathers soon after the sun is down, and makes its display while 

 the sky is still bright. So it fails to be very effective as a show, 

 although casting upon the western sky broad streaming radiations 

 of glowing surface. 



The secondary glow promptly follows and makes the chief 

 display. It differs from the secondary Krakatab glow in the 

 earlier time when it takes place, being nearly finished before any 

 stars are visible. The Krakata~o secondary lingered until after 

 full darkness, settling down into a low blood-red stratum simu- 

 lating the reflection of a remote conflagration. That peculiar 

 simulation was entirely absent from the late appearances. Both 

 at its close and throughout its course this secondary glow sub- 

 stantially resembles the primary glows as seen in 1884. It 

 especially resembUs the latter in presenting a well-defined and 

 serrated upper edge bordered by dark sky. That, however, h ;d 

 small and numerous serrations, apparently due to cumuli upon a 

 very remote horizon. The serrations of this, on the contrary, 

 are large and broad, the interspaces being apparently the inverted 

 shadows of cloud-masses upon a somewhat near horizon. 



It seems evident that the reflecting stratum of haze in the late 

 appearances was very low down as compared with the Krakata"b 

 haze. Hence the rapid succession of the glows. The reflected 

 rays of the sun, traversing a much smaller extent of the lower 

 atmosphere, show less red, having less of the other colours inter- 

 cepted. For the same reason, they retain force enough for a 

 third reflection, in which a very pure though faint red appears. 



Honolulu, July 25. Serena E. Bishop. 



Globular Lightning. 



The following account of a display of globular lightning will, 

 I think, be of interest to your readers, as it was well observed 

 by several independent ob-ervers, and differs in some respects 

 from those previously recorded. It is greatly to be wished that 

 this phenomenon could have its place assigned to it in electrical 

 theory. 



_ On Monday, the 5th instant, at midday, this district was 

 visited by a violent storm of rain, which lasted half an hour, and 

 was accompanied by thunder and lightning. When the storm 

 had passed ov^r and the sky was getting bright, a rod-like object 

 was seen to descend from the sky. It is described as being of a 

 pale yellow colour, like hot iron, and apparently about 15 inches 



long by 5 inches across. These dimensions are given by an 

 observer who estimated its distance (about correctly, as it sub- 

 sequently appeared) at 100 yards, and are not therefore affected 

 by the uncertainty attaching to estimates of the sizes of objects 

 whose distance is quite unknown. This object descended 

 " moderately slowly," " not too fast to be followed by the eye" 

 and quite vertically. 



On reaching a point about 40 feet from the ground, and in 

 close proximity with a chimney-stack belonging to a house in 

 Twickenham Park, the object seemed to "flash out horizontally 

 as if it burst," showing an intensely white light in the centre and 

 a rosy red towards the outer parts. At the same instant a violent 

 explosion was heard, and soon afterwards a strong smell was 

 perceived, which is described by the observers as " resembling 

 that of burning su'phur," for which thes;nell of ozone and nitric 

 oxide might easily be mistaken. 



Ordinary lightning is frequently most capricious in its action^ 

 In this respect this globular flash was in nowise behind. 



I examined the outside of the chimney stack carefully, but 

 no external effect whatever was visible. Inside, however, remark- 

 able effects were produced, and I quote the following : — 



" The back rooms consist of (i) basement kitchen ; (2) ground 

 floor dining-room ; (3) first and second floor bed-rooms, and at the 

 top a half attic. A stack of chimneys runs up the whole, and 

 projects about 6 feet above the roof There are no chimney- 

 pots. No one was in any of the rooms except the kitchen, in 

 which the servants were, and in which a fire was burning. 



" The explosion filled the kitchen with smoke and soot. The 

 dining-room also was filled with smoke and soot, though no fire 

 was burning in it. 



"The master of the house was ju?;t coming into the dining- 

 room from the conservatory when he heard the detonation and 

 simultaneously saw a bright flash of light. He staggered back 

 a moment, and then ran through the smoke and soot to the hall, 

 and called out to know if anyone was hurt. Finding all safe he 

 returned into the dining-room. A Japanese umbrella set open 

 as an ornament in the empty grate, but not fixed in any way, 

 was undisturbed, though the hub of it was hot to the 

 touch. Piles of soot spread out in a semicircle to 

 the centres of the side walls of the room, and an 

 arm-chair, which had been standing close to the fire-place, was 

 6 feet from its previous position, and had evidently been turned 

 round and thrust against the wall. In the bed-room, on the first 

 floor, soot was on the floor and in the fire-place. The slab of 

 marble forming the architrave under the mantel- shelf, and ex- 

 tending the whole width of the fire-place, had been thrust out 

 from its setting, and was, with a number of bricks, lying 6 feet 

 away on the floor. The mantel-shelf and pier-glass were undis- 

 turbed. In the secDnd-floor bed-room, soot and mortar were in 

 the fire-place and on the floor ; one end of the grate was broken 

 and a piece of the detached cast iron (some 3 inches square) was 

 lying against the wall 6 feet to the right. In the attic bed-aoom, 

 mortar reduced to the condition of fine silver sand was lying in 

 the fire-place and on the floor ; the wash-stand, which stood against 

 the fire- place, was pushed some 2 or 3 feet towards the centre of 

 the room, but not overturned ; and the carpet was rumpled up. 

 There is in this room a bell on the wall opposite the fire-place, 

 and a helical check-spring passes from this bell to an attachment 

 in the wall. At this point of attachment a piece of plaster of the 

 size of one's hand had been detached from the wall, and was 

 found near the fire-place, 18 feet off at the other end of the 

 room." 



At this time, when electrical theory is receiving so much atten- 

 tion, the views of a theorist such as Dr. Lodge would, I think, 

 be of great interest on the subject of these rare discharges. To 

 all appearance a detached portion of something — is it atmo- 

 spheric, or ethereal? — is carried along bodily through the air, 

 bearing with it a very considerable potential energy, and at the 

 same time radiating light. At an instant determined, perhaps, 

 by its proximity to the chimney-stack, its constraint is suddenly 

 relieved, and a discharge like ordinary lightning seems to occur 

 between it and the earth, vid (as it seems) the heated air of the 

 chimney. Has anyone an explanation for this ? 



A. T. Hare. 



Neston Lodge, East Twickenham, August 24, 



Cn some Effects of Lightning. 



I can fully corroborate Mr. A. F. Griflith's account of the re- 

 markable way in which two trees in a wood near St. Albans 



