Trans ACTiois^s of section a. 679 



Hegresenting light as area, these stars approximate very happily to steps of 

 quarter magnitudes. 



Half-a-dozen sheets are laid, blue side down, on a sheet of lead, the original 

 map laid over them, and the stars punched through with the proper-sized needles. 



3. At night a copy is laid on a writing-desk with a sloping ground glass top, 

 and illuminated with a night light, which also keeps them dry. 



The meteor track (when observed) is marked in pencil along n celluloid rulei 

 with a blackened bevel-edge, which, being transparent, does not hide the 

 configuration of the stars on the map. 



4. Obseriing. After comparing my watch with Greenwich time, I sit back in a 

 hammock choir with the illuminated map beside me, a pencil and ruler handy. I find 

 I can hold my eye far more steadily on the meteor's place than a wand held in the 

 hand, which I therefore do not use. I cannot usefully extend my field beyond 45° 

 on either side of the point facing me, except for bright meteors. I let my eyes 

 continually rove about, and when a meteor appears I fasten on it at once, and 

 all the stars fade out ; but only for an instant during which I am free to observe 

 the magnitude.! colour, speed, and streak. Presently the nearest stars begin to 

 glimmer out again and set themselves as a framework round the place of the 

 meteor. But I do not look away at them tdl I have thoroughly impressed a 

 mental picture of the meteor as part of the scene before me. Whilst doing so I 

 estimate its duration. But the most important thing is the direction. I follow 

 its line cautiously backwards and forwards, prolonging it until I find suitable 

 reference stars : either, that the line lies over a star — or passes a degree or two 

 from it — or cuts the distance between two stars in a certain proportion. Thus 1 

 get two reference points some ten or twenty degrees apart. Next I define to 

 myself the length of path as starting and ending on the line joining two stars, or so 

 many degrees before or after that line. 



lieturning to the estimation of duration, I use Professor Herschel's excellent 

 method of repeating the alphabet over at the rate of five letters to the second, 

 leaving out W — the only letter not monosyllabic. 



Now I look at my watch and note the time of apyearcmce. 



As to the advisability of using maps at all, if the observer knows the stars by 

 heart in configuration and by name, he may very well dispense with maps, &c., 

 describing the meteor and defining its position in words in a notebook iu the dark, 

 while still looking at the star lest he miss another meteor. But not many have 

 such knowledge : and the conciseness of the record — a single lino on the map — 

 recommends itself compared with a description needing many words. To look away 

 from the sky, down on the map, is a relief to the eye— at the cost, it is true, of 

 possibly losing a meteor, though it must be difficult to go on writing down the 

 description of one meteor while studying another. 



Looking down therefore on the map, I set the transparent ruler to the best of 

 my judgment, guiding myself by the reference points I have decided upon, and run 

 a pencil along for the length of path, finishing with a half arrow-head to show 

 the direction, and write the time alongside, and the description at the edge of the 

 map ; taking the line back also lightly towards the radiant. It is astonishing 

 how slight a shift satisfies or dissatisfies one, but it is worse than useless to look 

 up again at the sky. 



Next day the end points of the paths are read oflf for tabulation through a 

 'spider web' of R.A. and Decl. lines on tracing cloth laid over the map. 



G. Stationary Mtteor Radiants. Hy G. C. Bompas, F.R.A.S. 

 7. Cosmic Evolution, By Prof. A. W. BiCKERToN. 



