SCIENTIFIC SUMMARY. 
441 
Borax should he used as a flux, and the German silver granulated as is done 
for hard brass solder. 
The Mechanical Properties of Bronzes. — In a paper in the Comptes 
Bendus,” M. Tresca arrives at the conclusion that there are bronzes more 
homogeneous, ductile, resistant, and elastic than those produced in the 
State foundries ; and he calls on the Artillery Department to examine the 
products of private works so as to determine the bronze most serviceable for 
cannon. 
Action on Iron Pipes of the Sulphur contained in Water. — An important 
notice of this peculiar effect is given in a paper by Dr. E. Priwoznik in 
a late number of ‘‘ Dingler’s Polytechnic Journal.” It appears that when 
the iron mains conveying the mineral water from a source near Hainburg, 
Austria, were taken up after having been for more than a dozen years 
underground, the iron thereof had been strongly acted upon, as exhibited 
by the difference in structure upon the fracture. On being analysed, the 
author found the interior layer to consist, in 100 parts, of — Hydrated oxide 
of iron [(Fe 3 ) 203 ( 0 H)g], 81-08; free sulphur, 12-29; sulphuret of iron, 
4-48 ; hygroscopic water, 0-57 ; nickel, cobalt, magnesia, silica, traces of 
carbon, and chlorides of ammonium and sodium, 1-58. The second layer 
was found to contain only 79 2 per cent, of iron, but no sulphuret or excess 
of carbon was discovered ; while the third outermost layer was almost pure 
cast-iron. 
A New Mineral Trautwinite. — In the “ Proceedings of the Academy of 
Natural Science of Philadelphia ” (1873, p. 9), Mr. E. Goldsmith has given 
this name to a green mineral occurring in microscopic hexagonal crystals 
(pyramids with the prism, the latter sometimes three-sided) on chromite from 
California, specimens of which he received from Mr. John C. Trautwine. 
Chemical and blowpipe examination showed that it contained oxides of 
chromium, iron and magnesium. Heated to redness in the closed glass 
tube, it gave a little water and turned bluish green. Not dissolved in acids. 
MICROSCOPY. 
A Fact against Spontaneous Generation. — One of the most important 
papers for some time contributed to Natural Science is that in the “ Monthly 
Microscopical Journal ” for August, by Messrs. Dallinger and Drysdale, 
entitled Researches on the Life History of a Cercomonad.” These authors 
have done what has not been done before. They have, with the highest objec- 
tives and the utmost patience, completely watched the entire development of 
the creature at which they were working. They have “ continuously ex- 
amined, during sometimes as long a period as fourteen days, a peculiar 
monad, hitherto undescribed, but which is under some circumstances de- 
veloped in enormous quantities in the fluid resulting from the maceration 
of the head of the cod. This form passes through a remarkable series of 
changes, each of which might be taken for a distinct and independent crea- 
tion were not its evolution perfectly regular. Whilst working on this they 
observed a second form, which possessed only one flagellum instead of two. 
