324 
POPULAR SCIENCE REYIEW. 
chemist, Mr. Gowland, we gather some interesting facts as to Japanese- 
copper. The following analysis is given to show the composition of an 
average crude copper from Washiu : — 
Copper 
Lead 
Sulphur 
Iron . 
Silver 
Arsenic 
Antimony 
99-988 
trace 
0-947 
0101 
trace 
trace 
absent 
The Platiniferous Rocks of the Urals. — At a recent meeting of the French 
Academy of Sciences, M. Daubree described the rocks of the Ural affording 
platinum. They have a base of chrysolite. The masses come from the con- 
glomerates near Nischne Tagilsk, where platinum is obtained. Besides 
chrysolite, serpentine and chromic iron are intimately associated with the 
platinum. The facts seem to prove that the original platinum-bearing rock 
was a chrysolite rock more or less transformed into serpentine, and was 
accompanied with diallage, which is common in the specimens. The 
presence of chromic iron is also to be noted ; for it appears to bear evidence 
as to the changes through which the gangue rock of the platinum had 
passed. 
Effects of Cold on Iron. — -At a meeting of the Academy of Natural 
Sciences of Philadelphia, Mr. Willard referred to two instances of the brittle- 
ness of iron under the prevailing low temperatures which he noticed the day 
before. In breaking up an old locomotive, the cutting off of the rivet heads, 
which usually requires heavy sledging, was effected by a single blow, as if 
they were made of cast iron. In the forging of a long steamboat shaft of 
the best hammered iron which hung balanced in a crane, the hammering of 
the heated end caused vibration in the overhung end — harmless in ordinary 
temperatures, but at 10° F. sufficient to cause the beam to break sharp near 
the point of support. The published tests of iron and steel show no loss of 
tensile strength at low temperatures under a gradual stress, but all ex- 
perience shows great loss of lody, or ability to resist a blow. 
MICROSCOPY. 
The Way in which Echinoderms are developed. — The following are stated by 
the “Monthly Microscopical Journal” (June 1875) to be conclusions drawn 
up by Mr. A. S. Packard. — “Echinoderms as a rule, are reproduced alone 
by eggs and sperm-cells. After fertilisation of the egg they pass through : 
— 1. Morula stage. 2. Gastrula stage. 3. A larval, temporary stage (Plu- 
teus, Brachiolaria, Auricularia). 4. The Echinoderm grows from a water 
tube of the larva, finally absorbing the latter, whose form is often materially 
changed during the process. It thus undergoes a true metamorphosis,, in a 
degree comparable with that of some insects.” 
