REPORT ON THE DEEP-SEA DEPOSITS. 
335 
be urged that the native iron described from deep-sea deposits may have been derived 
from the decomposition of the basaltic lapilli or vesicular pumice, which are widely dis- 
tributed over the sea-bed. In reply to this objection it may be pointed out that the 
native iron in eruptive rocks is never circular in form, nor is it surrounded with a 
black magnetic coating, like the spherules from marine deposits. In the reputed cosmic 
dusts found in atmospheric precipitations or collected in snow-fields, there are frequently 
numerous, more or less hollow, spheres, or particles elongated like a bottle, with a 
cracked, brownish, more or less oxidised, surface. These we have found, from a careful 
examination, to be extremely numerous in industrial centres as well as in the scorise of 
steamships, and when they are broken down in an agate mortar they will sometimes 
yield minute particles of native iron. It is true that these particles are carried far 
and wide by atmospheric currents, and it has been suggested that the spherules of 
the deep sea have been derived from this source, but our examination shows that the 
cosmic spherules of deep-sea deposits are markedly different both in form and structure 
from the products of our furnaces, steam-engines, and materials of combustion. It has 
been stated that the particles of iron on the floor of the ocean may be due to the reduction 
of oxides of iron into metal under the influence of organic substances ; the consideration, 
however, of the form, structure, and distribution of the spherules does not in any way 
warrant this interpretation. 
During the past few years we have examined a large number of atmospheric precipi- 
tations collected from various parts of the world, for instance, from the Ben Nevis 
Observatory, from the coral island of Bermuda, and other isolated situations. In all 
these cases the bulk of the solid materials found in the precipitations was undoubtedly 
of terrestrial origin, and consisted chiefly of minute mineral particles derived from the 
rocks of the district from which the collections were obtained. In one instance from 
Ben Nevis there were two black spherules which approached in character those figured 
on PI. XXIII. , but they were too minute to admit of any definite opinion being formed, 
and the same was the case with one or two black spherules and crystalline flakes from the 
collections at Bermuda, which resembled the magnetic spherules and the plates of the 
crystalline spherules allied to the chondres, but here too the evidence was inconclusive. 
If particles of extra-terrestrial origin be continually attracted to the surface of the 
earth, which is in all probability the case, we should not expect them to fall more 
abundantly at one part of the earth’s surface than at another. In atmospheric precipi- 
tations, and on the surface of the continents, their recognition would necessarily be 
difficult on account of their small size, the large amount of telluric matter associated 
with them, and the mechanical actions to which they would be subjected. Those, how- 
ever, falling upon the ocean would gradually sink to the bottom, and in those areas of 
the ocean to which little or no detritus from the continents is carried, and in depths from 
which all carbonate of lime organisms are removed, they would, from these very c on 
