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Scientific Intelligence. 
7. Optical Properties of Leucite or Amphigene .- — Dr Brewster 
has also succeeded in separating the two images formed by the 
double refraction of Amphigene, and has ascertained that it has 
Two axes. It cannot, therefore, have the cube with either one 
or three axes as its primitive form. The circumstance of Haliy 
having assigned to it two primitive forms, viz. the cube and the 
rhomboidal dodecahedron, points it out as a remarkable mineral. 
It must now take its place under the Prismatic system of Mohs. 
8. Aerial Shadows seen from the Summit of Ben Lomond . 
- — On the 19th of August 1820, Mr Menzies, surgeon, Glasgow, 
and Mr Macgregor, began to ascend the mountain from Row- 
ardennan, about five o’clock afternoon. They had not proceed- 
ed far till they were overtaken by a smart shower ; but as it ap- 
peared only to be partial, they continued their journey, and by 
the time they were half way up, the cloud passed away, and a 
most delightful afternoon succeeded. Thin, transparent va- 
pours, which appeared to have risen from the lake beneath, 
were occasionally seen floating before a gentle and refreshing- 
breeze : in other respects, as far as the eye could trace, the sky 
was clear, and the atmosphere serene. They reached the sum- 
mit about half past seven o’clock, in time to see the sun sinking 
beneath the western hills. Its parting beams had gilded the 
mountain tops with a warm glowing colour ; and the surface of 
the lake, gently rippling with the breeze, was tinged with a yel- 
low lustre. While admiring the adjacent mountains, hills and 
valleys, and the expanse of water beneath, interspersed with nu- 
merous wooded islands, Mr Macgregor’s attention was attracted 
by a cloud in the east, partly of a dark red colour, apparent- 
ly at the distance of two miles and a half, in which he dis- 
tinctly observed two gigantic figures, standing, as it were, on a 
majestic pedestal. He immediately pointed out the phenome- 
non to Mr Menzies, and they distinctly perceived one of the gi- 
gantic figures, in imitation, strike the other on the shoulder, and 
point towards us. They then made their obeisance to the airy 
phantoms, which was instantly returned : they waved their hats 
and umbrellas ; the shadowy figures did the same. Like other 
travellers, they had carried with them a bottle of usquebaugh, 
and amused themselves in drinking to the figures, which was of 
course duly returned. In short, every movement which they 
made, they could observe it distinctly repeated by the figures in 
