368 DR. J. S. FLETT ON ASH DERIVED FROM [Aug. 1902, 
22. Nore on a Pretminary Examination of the Asn that fell on 
Barsanos after the Eruprion at St. Vincent (West Inprss). 
By Joun Suitu Frerr, M.A., D.Sc., F.R.S.E., F.G.8. Wirth 
a CuemicaL Anatysis by Dr. Wittiam Potrarp, M.A., F.GS. 
(Read May 28th, 1902.) 
Two samples of the material were sent by Dr. D. Morris, C.M.G., 
of the Imperial Agricultural Department for the West Indies, to 
Prof. Judd, who forwarded them to the Director of the Museum of 
Practical Geology. They consisted of a fine greyish-brown powder, 
not unlike ‘ flour-emery,’ but somewhat coarser and distinctly gritty 
to the touch. This powder was passed through a set of sieves, and it 
was found that 69 per cent. passed a sieve of 90 meshes to the 
inch, and 95 per cent. passed one of 60 meshes. All passed 30 
meshes to the inch. 
The ‘ash’ contains plagioclase-felspar, hypersthene, monoclinic 
brownish augite, apatite, and magnetite, with fragments of a brown 
glass. ‘The separated powders were all of much the same colour. 
Plagioclase-felspar is the most abundant constituent, mostly 
in broken fragments of very irregular shape. It belongs largely to 
labradorite, but appears to include more than one variety. 
Perfect crystals are not uncommon. Glass-enclosures are very 
numerous, and are frequently rectangular in outline: they often 
contain very small stationary bubbles. 
Many of the felspars have a thicker or thinner skin of glass 
adhering to their surfaces. This glass is brown, somewhat turbid, 
isotropic, with often many small rounded steam-cavities. The 
perfect crystals of felspar are often lozenge-shaped, as they lie 
on the broad flat brachypinacoid, being bounded by 001 and 201. 
Hypersthene is next in frequency. ‘The larger crystals are 
strongly pleochroic in green and reddish-brown tints, as is usual in 
a voleanic hypersthene which is rich in iron. The enclosures are 
glass-cavities with bubbles, and are often bounded by regular 
prismatic outlines. Magnetite is sometimes also seen in sharply- 
formed little octahedra in the hypersthene. Monoclinic augite 
is less common; it is browner in colour, less pleochroic, and 
contains fewer enclosures than the hypersthene. 
Both pyroxenes are often in perfect little crystals, showing prism- 
faces and both vertical pinacoids, and with roof-like terminations. 
Sometimes a little brown glass is adherent to their surfaces. Many 
of the hypersthenes are cross-twins. 
Magnetite can be easily extracted in fair quantities from the 
powder by a weak magnet. Its octahedra are often perfect. 
Apatite is undoubtedly present in rather large prisms; and 
there is another mineral, which appears to be zircon. 
Fragments of glass are numerous, and mostly smaller than those 
of crystallized minerals. The very smallest are minute threads and 
broken fragments, with curved or concave surfaces, such as are 
common in the tuffs that exhibit ‘aschen-structur.’ The larger 
