210 
erary purposes, or for the encouragement of the fine 
arts, or for the use or by order of any college, acad- 
emy, school or seminary of learning in the United 
States, or any State or public library, and not for 
sale, subject to such regulations as the Secretary of 
the Treasury shall prescribe. : 
Books, maps, music, engravings, photographs, 
etchings, bound or unbound, and charts, which shall 
have been printed more that twenty years at the date 
of importation, and all hydrographic charts and 
scientific books and periodicals devoted to original 
scientific research, and publications issued for their 
subscribers or exchanges by scientific and literary 
associations or academies, or publications of individ- 
uals for gratuitous private circulation, and public 
documents issued by foreign governments. 
Books and pamplets printed exclusively in lan- 
guages other than English; also books and music, in 
raised print, used exclusively by the blind. 
Books, maps, rousic, photographs, etchings, litho- 
graphic prints, and charts, specially imported, not 
more than two copies in any oneinvoice, in good faith, 
for the use or by order of any society or institution 
incorporated or established solely for religious, philo- 
sophical, educational, scientific, or literary purposes, 
or for the encouragement of the fine arts, or for the use 
or by order of any college, academy, school, or semi- 
nary of learning in the United States, or any State or 
public library, and not for sale, subject to such regu- 
lations as the Secretary of the Treasury shall pre- 
scribe. 
It may also be noted that the free list in- 
cludes specimens of natural history, when im- 
ported for scientific public collections and not 
forsale, and wild animals imported for zoolog- 
ical gardens. Personal effects of travellers pur- 
chased abroad are limited to the value of $100, 
but professional books, implements, instruments 
and tools of trade, occupation or employment, 
in the actual possession at the time of persons 
arriving in the United States are free of duty. 
THE GOLD RESOURCES OF THE YUKON REGION. 
THOSE interested in the gold resources of the 
Yukon region in Alaska should secure, from 
the Geological Survey, the report of the expe- 
dition made under the direction of Mr. J. E. 
Spurr last summer, a brief account of which 
was published in this JouRNAL on November 
27,1896. The party crossed the Chilkoot Pass, 
about the middle of June, to the headquarters 
of the Yukon, and proceeded down the river 
SCIENCE. 
[N. S. Vou. VI. No. 136. 
to the chief gold-bearing localities. The prin- 
cipal producing districts, those of Forty-Mile 
Creek and Birch Creek, were thoroughly ex- 
plored, as well as other less important localities. 
The party then continued down the Yukon, ex- 
amining the younger sedimentaries which over- 
lie the gold-bearing formation, as far as Nulato. 
One of the principal results of the expedition 
was the recognition of the gold-bearing rocks 
from which the gold in the river gravels is de- 
rived. These gold-bearing rocks constitute a 
distinct broad belt running northwest into 
Alaska from British territory. They are in 
their lower portions schists and gneisses, with 
intrusive rocks, and in their upper portion 
somewhat altered sedimentaries. They are all 
older than Carboniferous, for the Carboniferous 
and younger rocks overlie them on both sides 
of the gold-bearing belt. In this belt the gold 
occurs partly in quartz veins, partly in deposits 
formed along shear-zones ; in both occurrences 
it is contained in pyrite, and becomes free on 
weathering. The quartz veins are distinctly 
older than the shear-zone deposits, and were 
formed before the alteration of the enclosing 
rock to a schist; they have, therefore, partaken 
of this shearing, and have been broken and 
sheared so that they are typically non-persist- 
ent. The deposits along shear-zones are, how- 
ever, of later date than the shearing, and can 
be continuously followed. The younger beds 
which overlie the gold-bearing belt consist in 
part of conglomerates, and some of these con- 
glomerates are fossil placers, which give promise 
of being productive. 
GENERAL. 
THE French Association for the Advance- 
ment of Science is holding its annual meet- 
ing simultaneously with that of the Amer- 
ican Association. The meeting is at Saint Eti- 
enne, under the presidency of M. Marey, the 
eminent physiologist. 
AT a meeting summoned by the Lord Provost 
of Glasgow, and attended by representatives 
from the magistrates, the University, St. Mun- 
go’s College, the Philosophical and other sci- 
entific societies, it was unanimously decided to 
invite the British Association to meet in Glas- 
gow in the autumn of 1901. 
