SCIENTIFIC SUMMARY. 
439 
regards the movement of their waters. The dominant winds in this region 
blow, from May to October, from the north and north-west, and raise the 
mean level of the waters of the Mediterranean at Port Said, whilst they 
depress the mean level at Suez. The difference of level, which attains nearly 
40 centimetres (almost 16 inches) in September, sets up, in summer, a cur- 
rent from the Mediterranean to the Red Sea, which is interrupted by the 
tides, but nevertheless carries a considerable volume of water from north to 
south. In the winter, on the contrary, the south winds blow strongly, and 
the mean level of the Red Sea is then higher than that of the Mediterranean, 
the difference attaining a maximum of 30 centimetres (almost 1 footl. 
The general direction of the current of the Canal then sets from the Red 
Sea to the Mediterranean. The volume of water flowing annually from 
one sea to the other is estimated at about 400,000,000 cubic metres, and 
this, with the tidal currents, annihilates the effects of evaporation at the 
surface of the lakes, and aids the solution of the great salt deposit in the 
basin of the Bitter Lakes, which, instead of increasing, as was expected by 
some people, is actually diminishing, especially in the line of transit of ships. 
The tidal currents in the northern branch of the Canal between Port Said 
and Lake Timsah usually vary in velocity from 0T5 to 0-45 metre per 
second, but may attain 0-50 and O' 60 metre. Between Suez and the Bitter 
Lakes the width of the Canal being greater, the currents vary from 0-60 to 
1T0 metre per second, and may attain 1*30 metre. 
MINERALOGY. 
Milarite . — The results of earlier analyses of milarite show so great a dis- 
parity that Ludwig has been induced to submit a pure specimen of this 
mineral to analysis. The mean of his numbers are : — 
Silicic acid 
71-81 
Alumina . 
10-67 
Lime 
11-65 
Potash 
4-86 
Water 
1-36 
100-35 
These determinations indicate Si 12 Al 2 Ca 2 KHO 30 as that of milarite. 
Tschermak, who has investigated the optical properties of this mineral, finds 
'each crystal to consist of at least six individuals, combined with each other in 
positions inclined at about 120° ; they resemble in this respect crystals of 
aragonite, witherite, &c. The individuals appear to be twinned upon a face 
which, it seems, is to be regarded as oo P and all the crystallographic observa- 
tions so far made point to milarite belonging to the rhombic rather than the 
hexagonal system . — Jahrbuch fur Minerologie , 1878, p. 411. 
The Meteorite of Hungen . — Buchner and Tschermak have described the 
meteorite the fall of which was witnessed at Hungen, in the Province Ober- 
hessen, on the 17th of May last year. A portion weighing 73 grammes, 
which has been sent to the University collection at Giessen, shows the black 
fused crust. The mass of the stone is grey, and presents chondritic characters ; 
numerous enclosed particles of nickel-iron and troilite are to be seen scat- 
tered through it. Microscopic observations show the crust to consist to the 
