86 REPORT— 1870. 



the average position of the radiant-point was found to be very near the star d 

 Persei. The heights of the first and last points of the meteors' tracks 

 and the average of those heights are shown in fig. 5, by a graphic projection 

 readily exhibiting to the eye the height in the atmosphere at which the 

 shooting-stars of the August meteoric shower became ignited, and were 

 extinguished, during the appearance of the phenomenon in the present year. 



The additional correspondences of the Greenwich observations with those 

 meteor-tracks whose heights have already been determined, and with other 

 shooting-stars recorded at the diiferent stations (of which a summary will be 

 given in the next Report), are at present undergoing calculation ; and they 

 may be expected, on concluding the results of their investigation, to afford 

 interesting materials for comparison with the observed paths of the shooting- 

 stars recorded in the present list. 



1870, August 15th, 9" p.m., G. M. T., Scotland and Ireland. The position 

 of the very luminous streak which this meteor left was over the southern 

 part of the Hebrides, and the Atlantic Ocean north of Ireland ; but at what 

 distance from the land, and at what height in the atmosphere, it would 

 require a comparison of other descriptions of its course to ascertain. As the 

 sun was fully 12° or 13° below the north-west horizon of the region indicated, 

 it would stni be half that depth, or about 6°, below the horizon of the meteor- 

 streak, if its elevation was only as great as the height at which the largest 

 August meteors commonly develoj)e a very long enduring, phosphorescent 

 streak, about fifty-five miles above the level of the sea. 



1870, August 20th, 9" 24"" p.m., G. M. T., London, Cambridge, and Oxford. 

 The apparent courses of the meteor, as described at Clapham Park, London, 

 and at Linton, Cambridge, are almost identical, so as to afford no definite 

 conclusion of the meteor's height. At Wandsworth, near Clapham, Mr. H. 

 W. Jackson saw the meteor commence about the trapezium (/3, y) of the 

 Little Bear, and disappear halfway between Capella and Algol, while at 

 Linton it disappeared almost over a Cassiopeiae. With the distance of forty- 

 five mUes between the latter places, and a parallax of 32° for the last point 

 of its visible course, these observations give the place of disappearance at a 

 point about twenty-one mUes over Bury St. Edmunds. As this place is within a 

 few degrees of the altitude and direction at which its disappearance was 

 observed at Combe, near Woodstock, in Oxfordshire, it may be accepted, 

 probably, as very near to the true position of the point at which the meteor 

 disappeared. 



The exact place of the meteor's first appearance cannot be absolutely 

 ascertained. But supposing its apparent course at Linton to have passed 

 about 20° north of tho zenith, and to have descended " almost perpen- 

 dicularly " (with an inclination of about 20° from the north of vertical), as 

 it was perceived to fall towards the eastern horizon at Woodstock by Mr. J. 

 Abrahall, its real course, preserving tho apparent path which it appeared to 

 have at Wandsworth, began from the direction of a radiant-point between the 

 head of Bootes and Corona BoreaUs, at about R. A. 230°, N. Decl. 35°. At 

 its passage due north of London the height of the meteor, on this assumption 

 of its initial direction, was about fifty-three miles above a point between 

 Huntingdon and Cambridge, descending towards its point of extinction from 

 an inclination of 45° above the due west horizon. A more complete knowledge 

 of this extremely brilliant meteor's real course can only be obtained, to 

 coiToborate, or correct, the present provisional determation, if notices of its 

 appearance were obtained by observers at other places, who would com- 

 municate to the Committee a description of their observations for this purpose. 



