166 Prismatic Spectra of the August Meteors. 



Two observers being engaged to watch on this night, one 

 checked the observations of the other with the naked eye. 

 The troublesome reflected image in the spectroscope could 

 accordingly be dispensed with, and it was kept out of sight ; 

 so that the views obtained of the meteor spectra came as 

 nearly to perfection as could be wished. 



August 10th, continued. — No. 7 ; 4h. 22m. p.m. Equal to a 

 first mag. star. Shot from 7 Oephei to 1 Draconis in three- 

 quarters of a second ; leaving a bright streak for five seconds 

 on its course. The meteor first appeared in the field of view, 

 and passed out of it. The brightest portion of the streak, 

 however, was brought into the middle of the field of view; 

 where it occupied an excellent position, parallel to the refract- 

 ing edges of the prisms, for viewing its prismatic spectrum. A 

 slight effect of distortion (produced in the prisms) caused it to 

 appear bent, like a bow, across the field of view (Fig. 7) . The 

 spectrum presented the appearance of a narrow line of light, 

 exceedingly brilliant, of a golden-yellow colour, and not more 

 than 5' in width. It faded gradually along its whole length, 

 and disappeared in about two and a half or three seconds. 

 Its description, noted in the register, kept for the purpose at 

 the time, was — " neither double, triple, nor multiple, nor con- 

 tinuous, but purely and positively mono-chromatic." 



August l\th. — No. 8; Oh. 15m. a.m. Equal to a third 

 mag. star. Shot from /3 Cephei to 8 Draconis, in three-quarters 

 of a second ; leaving a luminous streak for two seconds. The 

 spectrum of the streak was a remarkably slender, orange- 

 yellow line of no appreciable breadth, without any continuous 

 spectrum near to it, or any other neighbouring bands, or 

 lines. It was very bright, remaining in sight two seconds ; 

 and it gradually faded away until it vanished. The spectrum 

 of the nucleus appeared to be undistinguishably the same as 

 that of the streak. 



No. 9 ; Oh. 20m. a.m. Equal to a third mag. star. Shot 

 from a Cephei to 33 Cygni (M.), in three-quarters of a second; 

 leaving a streak for one second, and a half. The spectrum of 

 the streak was dull grey, diffuse, about 5 in width, with a 

 yellow line included in it, on the side toivards the red. The 

 yellow line and the diffuse band disappeared together. The 

 spectrum of the nucleus, appeared to be appreciably the same 

 as that of the streak. 



No. 10; Oh. 33m. a.m. Equal to a fourth mag. star. 

 Shot from p Cassiopeiaa to Honorum, in half a second; 

 leaving no streak. The spectrum of the nucleus appeared to 

 be concentrated into a few faint lines with wide intervals be- 

 tween them, but this description is very uncertain. 



No. 11 ; Oh. 33m. a.m. Equal to a third mag. star. Re- 



