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POPULAR SCIENCE REVIEW. 
lime, magnesia, sal ammoniac, and tartar are added, little at a time, and 
the whole is briskly stirred for about half-an-hour, so as to mix thoroughly, 
after which the tin is thrown on the surface in small grains, stirring until 
entirely fused. The crucible is now covered, and the fusion kept up for 
about thirty-five minutes, when the dross is skimmed off, and the alloy 
found ready for use. It is quite malleable and ductile, and may be drawn, 
stamped, chased, beaten into powder, or into leaves, like gold-leaf. In all 
of which conditions it is not distinguishable from gold even by good judges, 
except by its inferior weight. The alloy has already been largely applied in 
the United States, and requires only to be known in Great Britain to become 
& favourite. — Vide the Engineer , July 19. 
METEOROLOGY. 
Classification of Meteorites. — A classification of meteorites which will be 
found useful by those engaged in the study of these bodies, has been given 
by M. Daubree in a paper read before the French Academy in July. M. 
Daubree divides all meteorites into two primary groups, Siderites and Aside- 
rites — the former being characterised by the presence of metallic iron, and 
the latter by its absence. The Asiderites contains one group only, which is 
termed Asideres. The Siderites are divided into two sections : in the first 
the specimens do not enclose stony particles, and in this we find the group 
of Holosideres ; in the second both iron and stony matter are present. This, 
then, includes two groups : Syssideres, in which the iron is seen as a con- 
tinuous mass 5 and Sporadosideres, in which the iron is present in the form 
of scattered grains. 
A Town without Ozone. — From the experiments which have been made 
since 1852 by the Hydrometric Commissioner of Lyons it would appear that 
the atmosphere of this town is devoid of ozone. The results more recently 
arrived at by the officials of the Imperial Observatory point to the same fact. 
The observations conducted by these workers have not yet been published 
in full. Meanwhile, M. Fournet gives the conclusions arrived at by his 
resumed observations at Lyons and the suburbs, with the co-operation of 
M. Lambert and Rassinier. While ozone was very abundant at Sauvage, 
on the heights of Tararae, a range of hills separating the basins of the Loire 
and Rhone, traces were barely perceptible once or twice a month at Lyons. 
It is well known that it has been often maintained that the arrival of the 
cholera was coincident with the disappearance of ozone in the air. The 
example of Lyons does not agree well with this assertion ; this city is not 
subject to cholera, and, at the same time, its atmosphere is always deprived 
of oxygen. — Vide Foreign Correspondence, Chemical News, July. 
Rainfall of the 1 6th July. — In his “ Magazine ” for August, Mr. Symons 
dwells upon the more remarkable features of this severe rainfall. Without 
attempting to explain the fact that in some localities the rainfall was twice 
that of others, at a distance of a few miles, he gives the more striking 
examples. For instance, twice as much rain fell at Deptford as at Camden 
Town, one having 4 inches and the other 2|, the distance between the two 
being only seven miles. Again, at Maidstone, the fall was equal to 2'7 
