OBSERVATIONS OF LUMINOUS METEORS. 373 



straight wand held up to direct it, soon assuring an observer that the eye 

 without an assistance of this kind is a very fallacious guide. But by 

 using for the picture of the stars the same principles of plane perspective 

 representation which are used habitually for pictures of ordinary objects, 

 the straight wand and the straight path of the meteor in the sky when 

 drawn upon the map are also straight lines, and may be prolonged, not 

 only with greater ease to other parts of the map than in the sky, but also 

 by a pencil they may be marked indelibly upon the page or sheet, so that 

 comparison with many successive lines thereupon becomes not a doubtful 

 and uncertain, but an easy and perfectly unerring operation. In accord- 

 ance with the most recent practice of Herr von Konkoly, of Komorn, 'in 

 Hungary, as well as of the late Professor Heis, the Committee has pre- 

 pared celestial charts in plane perspective, with whose assistance the posi- 

 tions of the centres of departure of different meteor showers can be easily 

 vei'ified and investigated by observers, and farther particulars regarding 

 their intensities and durations may be ascertained. 



As a guide for the selection of meteor showers for special study, the 

 Committee refers observers to the Key Map and General Catalogue of all 

 such known meteor systems published by the British Association in the 

 volume of its Annual Reports for the year 1876, by Mr. Greg ; where the 

 relative importance, as resulting from the richness and constancy of meteor- 

 showers, in returning at the annual epochs of their visibility is stated 

 and represented. The principal characteristics of the meteors, including 

 their colour and brightness, the apparent lengths, speeds, and durations of 

 their nights, and the presence of sparks or streaks in their tracks, have 

 hitherto been very little noted, and such peculiarities belonging to the 

 showers, as well as their dates of principal abundance, and the exact 

 positions of their radiant points, form very important and interesting 

 subjects of inquiry. 



The observation of sporadic shooting -stars is necessarily less attractive- 

 and suitable to ordinary observers than mapping the apparent paths of 

 meteors belonging either to the well-known major and " special " or to 

 some minor annual meteor showers. But as regards the observations, 

 the method of procedure is the same, with the exception that long-con,- 

 tinued watches maintained for a whole night are, in general, indispensable 

 to a successful collection of their tracks by a single observer. Should 

 no indications of a new shower accidentally occur by unusual frequency 

 of meteors from a new radiant-point in evening watches of a single 

 night, yet the detection of such a shower is no uncommon recompense of 

 an observer's vigilance in a morning watch, or among the meteor-tracks 

 recorded on a few successive nights. As the same remark applies to the 

 accidental vision of bolides and fireballs, the same instructions will 

 suffice, and the same course may be pursued most advantageously by 

 observers in recording sporadic shooting-stars as in describing large 

 meteors that may be occasionally observed ; and these in the next para ( - 

 graph will be more fully indicated and described. 



III. Bolides and Fireballs have the singularity among meteors, and the 

 pre-eminence over shooting-stars of attracting the attention of a great 

 number of observers. This is also the case with meteor showers when 

 they are sufficiently abundant to lead to general observations and to con- 

 clusive determinations of their radiant-points, although poor and scanty 

 showers escape this identification for lack of a sufficient number of 

 observations. As, however, by the displacement of his point of view, a 



