362 Prof. Forbes's Account of a remarkable Meteor. 



nishing direction in Professor Kelland's remarkable observa- 

 tion at Granton. 



2. The Durham observation is compatible with the above- 

 mentioned group within the limits of error. By the combina- 

 tion of Durham and Edinburgh (the base line perpendicular 

 to the assumed direction of the meteor's motion being ninety- 

 five miles), I calculated that the meteor passed vertically nearly 

 over the Island of St. Kilda, with an absolute elevation of 

 about eighty-eight miles. But this solution seems absolutely 

 excluded by observations at Glasgow which admit of no ques- 

 tion, and which I have spared no pains in verifying. Had 

 the position of the meteor been such as I have first assumed, 

 it could not possibly have been seen over even the roofs of the 

 houses from the station occupied by Mr. Stevenson, much less 

 over the chimney-tops. The bearing at the moment of ex- 

 plosion at Glasgow, also singularly enough corroborates suf- 

 ficiently well the comparatively small elevation (about twenty 

 miles above the earth) which the combination of Edinburgh 

 and Glasgow gives ; and this bearing we have seen to have 

 been also accurately defined by the physical obstacles bound- 

 ing the observer's view ; it would have given a parallax of 15°, 

 subtended by the perpendicular on the meteor's path, referred 

 to Glasgow and Edinburgh respectively. Now, if this calcu- 

 lation were anything like correct, the Perth observation is 

 entirely wrong; and the meteor could not have risen about 

 6° above the horizon of Durham, instead of 10° or 11° as esti- 

 mated. I am unable in any degree to explain these conflicting 

 results. 



3. The observations of Professor Kelland at Granton, and 

 those at Perth, through the great azimuths of 125° and 

 130°, described by the meteor with such remarkable delibe- 

 ration of motion, lead, when analysed, to the very same results 

 which presented themselves to the mind of the spectator in- 

 tuitively ; namely, that the motion must have been sensibly 

 rectilinear, equable, and parallel to the horizon at Edinburgh. 

 Assuming that the greatest altitude at Edinburgh was 15°, 

 and the bearing then N. 63° W. (true), we may calculate that 

 the altitude should have been on this hypothesis, when first 

 seen by Professor Kelland, 1 1° 47', instead of 12° as observed; 

 at explosion, (5° 59' (7° observed), and at its final disappear- 

 ance 0° 47' (instead of 0° 30' observed). Again, at Perth, the 

 observed altitude, when first seen, was 3|°, and the calculated 

 altitude 5° 3', taking the maximum altitude at 17^°. The 

 coincidence is, on the whole, remarkable; though it would be 

 rash to push it to an extreme, as an error of some degrees 

 may exist in the assumption of the direction of the meteor's 



