148 Proceedings of the Royal Society of Edinburgh. [Sess. 
XVI. — Note on Conditions for Mirage on the Queensferry Road. 
By Alex. G. Ramage. 
(Read July 4, 1921. MS. received September 21, 1921.) 
The surface of the Queensferry Road, from about the bend above 
Blackhall, past Marchfield, and on towards Cramond Bridge, was remade 
in the spring 1919. 
It was made in the modern fashion for a motoring road, with road 
metal and liberal supplies of bitumen, and small pieces of quartz scattered 
on top of the bitumen, the whole being rolled by steam roller. 
After this had been done, although I watched carefully throughout 
the summer, no signs of the mirage, so common on this road during the 
previous summer, made their appearance until August, and then but 
faintly. This in my opinion points to a triturated condition of the quartz 
under road traffic, as being an essential factor in the phenomenon. During 
the summers of 1920 and 1921, on bright days, mirage was much in 
evidence on this road at the places described in my paper, and at other 
parts in the vicinity. 
The following observations made during August 1921 may be of 
interest. 
I have had occasion to use the Craigleith Road (which branches off 
from the Queensferry Road near Craigleith Station and joins the Comely 
Bank Road) frequently this year, and have carefully looked for mirage, 
but saw none. The surface is “old” and not to be distinguished from 
that of the Queensferry Road when mirage was observable, It is smooth, 
with the small stones well embedded in the bitumen. On the south 
side there are open railings, so that the sun reaches it without obstruc- 
tion. Compared with the Queensferry Road there is little traffic. 
Recently the Queensferry Road between Lord Salvesen’s house and 
Craigleith Station has been resurfaced, and considerable traffic has been 
diverted round the Craigleith Road. On the 15th August 1921, weather 
hot and sunny, I walked from the bus terminus at Comely Bank along 
the Craigleith Road and saw an isolated spot of water on this road, but 
no reflection. Walking on through Blackhall on Queensferry Road, I 
found the two yellow advertisement boards clearly reflected from the 
road, and some children’s coloured clothes were well reflected just at the 
