THE MINERALOGY OF SCOTLAND. 451 
by the magnet. Much the larger proportion of this was decidedly, though none 
of it very strongly, magnetic; perhaps a fiftieth was very feebly or almost non- 
magnetic. An attempt was made to separate it totally from quartz sand, 
by stirring up in water and rapid decantation of the latter, but the separa- 
tion was not quite perfect. The most highly magnetic portion of this sand 
yielded 
On 1 gramme— 
Titanic Acid, ; : : : j 19:4 
Ferric Oxide, : : . : : 37° 972 
Ferrous Oxide, . : : F : 24.°325 
Manganous Oxide, °8 
Lime, . 3 Z : : ; . 6°5 
Silica, . : s : ; , 2 10°8 
99 :'797 
Examined with the microscope, this portion had a black colour inclining to 
blue. It showed many apparently regular octohedra; some of these had 
apparently all their six angles truncated by the faces of the cube. Two dis- 
torted cubes, like square prisms, were seen also. The truncation of six angles 
by square faces would prove this species to be cubic; and the crystals not to be, 
as held by some, acute rhombohedra with merely the summit and basal angles 
truncated. 
8. The non-magnetic portion of the black sand, of which there was a com- 
paratively small portion mixed with the more highly magnetic, yielded 
On 1 gramme— 
Titanic Acid, : : : ; 15 
Ferric Oxide, : : : : ; 40°729 
Ferrous Oxide, . , ‘ : : 18: 244 
Manganous Oxide, . : Ae: 
Lime, . : : ‘ F ie 
Silica, . : : ; ; ; : Cota | 
100°0738 
The colour of this portion was rusty brown. 
Examined with the microscope, it showed a hackly structure, no crystals 
and no cleavages. There was a good deal of non-separable adherent silica. 
These two black sands, therefore, though found within a short distance of 
each other, and gathered within two years of each other, differed considerably, 
both physically and chemically. 
9. From the sea-shore, a little east of the mouth of the Almond, Mid- 
VOL, XXX. PART Il. 4A 
