JANUARY 21, 1904] 
NATURE 
281 
swhen we consider our whole trade, import and export, with 
our colonies and with foreign countries.’’ The ‘‘ analysis 
‘of the conditions of our foreign trade,’’ the article states, 
““leads us back to the ground that the advocates of the 
change would do well never to have quitted, viz. the com- 
‘parative merits of the metric and imperial systems. . . 
As regards all such important points as logical arrangement 
-and symmetry, ease and swiftness of calculation, simple and 
direct connection among the fundamental units of length, 
weight, and volume, there can be no possible room for 
doubt as to the vast superiority of the metric system.’’ The 
other article is by Mr. W. C. D. Whetham, and is entitled 
“Matter and Electricity.” It gives a good and complete 
account of the scientific work of the last seven years, or so 
fay as radiation and radio-activity are concerned. The re- 
searches of Becquerel, J. J. Thomson, Rutherford, the 
‘Curies, Crookes, Dewar, Ramsay, Soddy, and others are 
passed in review, and a clear idea is given of what, in the 
‘opinion of the best authorities, is the probable physical 
significance of the results obtained. 
Tue December number of the Agricultural Students’ 
‘Gazette (Cirencester) contains a lecture given at the college 
iby the new honorary professor of forestry, Dr.’ W. Schlich, 
which is of special interest in view of the attention which 
forestry and education in forestry are receiving at present. 
By an appeal to figures, the professor showed that the 
demand for timber in this country increases steadily, and 
that our foreign supplies rest on an unsafe basis. The 
British forester has therefore a double incentive to mend 
his ways, for not only is there the prospect of an advance 
in prices, but he may, if he will, replace by home-grown 
timber part of the present imports. In discussing the 
question, ‘‘ Will it pay?’’ Dr. Schlich had to confess that 
British forests supplied him with no satisfactory data, for 
none has been sufficiently long under scientific direction, 
‘but he was able to show what had been done by Saxony 
under conditions which are not very different from ours. 
The forests of that State, which occupy close on half a 
million acres, have been systematically worked by the 
‘Government for more than a century, and since 1817 re- 
cords have been kept. In 1817 the produce was 61 cubic 
feet, in 1893 92 cubic feet of timber per acre; while the 
net return eighty years ago was 4s., and in 1900 was 
22s. 6d. per acre. After discussing the cost of production, 
the lecturer said he estimated that a purchaser who was 
content to accept 23 per cent. for his money might pay for 
jand for oak growing gl. 1os., for spruce 15/., for ash 24l., 
and for larch 34l. per acre. As oak requires a much better 
soil than spruce or larch, it is evident that the profits from 
growing timber will vary widely with the species grown. 
The above figures, however, do not take account of diseases, 
‘and these sometimes seriously affect profits. Larch, the 
most valuable of our trees, readily falls a prey to Peziza 
Willkommi, and so destructive has this parasite become 
of late years that Dr. Schlich fears it may make profitable 
jarch cultivation impossible. 
Ir appears from the work of the expedition under Colonel 
‘Spindler, which has lately explored the Gulf of Kara-bughaz, 
that this interesting appendix of the Caspian Sea has a 
great commercial value, its bottom being covered with 
‘immense layers of nearly pure Epsom salt (mirabilite). This 
large gulf, which covers 7o80 square miles, and has only 
a depth of from 34 to 36 feet, is now separated from the 
Caspian Sea by two narrow sand peninsulas which are 
nearly joined at their ends, leaving only an 86 fathoms 
wvide channel, through which the water of the Caspian 
NO. 1786, VOL. 69] 
continually rushes into the gulf, to be evaporated there, 
leaving its salts to be deposited at the bottom. From 18 to 
33 cubic kilometres of water enter in this way the gulf 
every year, and under the rapid evaporation which goes on 
there (3-2 feet per year) the salinity of the water in the 
gulf attains as much as 16-3 per cent. Consequently, the 
bottom of the Kara-bughaz consists now to a great extent 
of gypsum or of Epsom salt, and it is calculated by the 
chemist of the expedition, A. Lebedintseff, that the deposits 
of pure Epsom salt must cover an area of about 1300 square 
miles, and have a thickness of 7 feet or more. Owing to 
the small depth of the gulf, this salt can easily be extracted 
by means of excavating machines. 
Tue additions to the Zoological Society's Gardens during 
the past week include a Rhesus Monkey (Macacus rhesus) 
from India, presented by Mrs. Hughes; a White-backed 
Piping Crow (Gymmorhina leuconota) from Australia, pre- 
sented by Mr. H. Brack; a Ring-necked Parrakeet 
(Palaeornis torquatus) from India, presented by Mrs. Watts ; 
three Yellow Baboons (Papio cynocephalus) from Africa, 
three Impeyan Pheasants (Lophophorus impeyanus) from 
the Himalayas, two Rufous Tinamous (Rhynchotus 
rufescens) from Brazil, two Tuatera Lizards (Sphenodon 
punctatus) from New Zealand, deposited. 
OUR ASTRONOMICAL COLUMN. 
InTENSITY oF AtmospHERIC LINES IN THE SOLAR SPECTRUM. 
—The results of an interesting research on the intensities 
of the atmospheric lines in the solar spectrum are published 
in No. 8, vol. xlviii., of the Harvard College Observatory 
Annals. The widths of various lines in the D, a and B 
regions were measured on the solar spectrum charts pre- 
pared by Higgs under various recorded atmospheric con- 
ditions and solar altitudes. The results thus obtained, after 
suitable reduction to standard conditions, were analysed, 
and in cases where a difference exceeding a fixed minimum 
was found to exist between the width of a line at “* high ” 
sun and its width at ‘flow ”’ sun, this line was attributed 
to absorption in our atmosphere. The lines thus deter- 
mined as ‘‘ atmospheric’? were compared with those 
similarly designated by Rowland, and in a few cases in 
each region the decision of that observer, as to whether a 
line was truly solar or atmospheric, has been reversed. 
Measurements of the widths of six atmospheric lines 
between AA 5867-8 and 5905-5 were made on sixteen charts, 
and the results arranged in a table in which the charts were 
placed in order of the sun’s altitude at the time each chart 
was drawn. According to the general result the lines 
should show an increase of width proportionate to the 
lengths of the paths of the rays through our atmosphere, 
this increase of width being probably due to the moisture 
present in the atmosphere. Some abnormal widths were, 
however, noted, and were found to agree, in effect, with 
Higgs’s remarks as to the state of the atmosphere at the 
times the respective charts were made. From these results 
it is concluded that this method is probably the most accurate 
one known for determining the total amount of moisture, in 
the line of sight, in the earth’s atmosphere. 
OBSERVATIONS OF JUPITER.—Some interesting results of 
observations of Jupiter during 1903 are published by Mr. 
Denning in No. 340 of the Observatory. Between May 26 
and November 19 the planet was observed on eighty-four 
nights, 1200 transits of various markings being observed. 
It is proposed tg continue the observations until the end of 
the present month, and then to publish the complete results. 
A few of the more important points in the observed pheno- 
mena may, however, be mentioned now. 
During the six. months completed at the end of November 
the rotation perod of the Great Red Spot became some- 
what lengthened, the mean value being gh. 55m. 41-7s., as 
compared with 9h. 55m. 390s. in 1902. The large south 
tropical spot, visible since the spring of 1901, is still easily 
seen, and has a rotation period of gh. 55m. 19s. This spot 
