of Edinburgh, Session 1881-82. 
583 
I am then, necessarily, in the position of an advocate on the 
opposite side engaged in cross-examining a witness. 
In the article Optics of the eighth Edition of the Encijclopcedia 
Britannica , an article by Sir David Brewster, there is recounted 
a case of Atmospheric Detraction observed and described by 
Professor Vince ; it is illustrated by a copy of a view of the 
phenomenon. A single glance at that picture, by any one habitu- 
ated to observation, is enough to convince him that the phenomenon 
thereby depicted could never by possibility have been seen. It 
is a view of Dover Castle as seen from Ramsgate, and represents a 
rectangular building with a square turret at each corner. Passing 
by, for the present, its most glaring feature, I remark that the 
faces to the right hand are in deep shadow, the shadow of the 
building itself upon the ground is also to the right. The faces 
toward us are in sunshine, and the tower on the left throws its 
shadow on the centre wall as if from a sun behind us to the left 
at an azimuth of some 40°. The side-wall again forms a shadow 
on the right hand distant tower at an elevation of some 60°. How 
Dover is almost exactly S.S.W. from Ramsgate, wherefore the 
sun must have been in the H.E. at an elevation of 60° ; a 
direction from which the sun never shone upon Great Britain. 
The time of the observation is stated to have been 7 o’clock in 
the evening of the 6th August. At that time the sun was about 
to set in the W.H.W. Surely the Professor of Astronomy at 
Cambridge could not have made a blunder which puts the sun 
in the neighbourhood of the star Vega, circumpolar to us ! The 
article in the Encijclopcedia concludes with “ See Edinburgh 
Transactions , vol. iv. p. 245 ; ” and as evidence at first hand is 
better than evidence by hearsay, we shall consult the Transactions. 
We there find the original description of the phenomenon as 
read before the Royal Society of Edinburgh, on the 5th of Janu- 
