26 
and argon do not pass through red-hot 
septa of platinum, palladium or iron. It. 
is well known that hydrogen passes with 
great ease through such septa, either owing 
to solubility in the metal or the formation 
of easily decomposable compounds. Pro- 
fessor Ramsay’s experiments imply the 
inability of helium or argon to form any 
even unstable compound with these metals 
or to dissolve in them at red-heat, another 
evidence of the inertness of these gases. 
Tue following from the Chemical News 
deserves to be quoted in full: ‘‘ Atomic 
‘Models (Patent No. 1999, 1897). A patent 
has recently been granted to Mr. Frederick 
George Edwards, of London, by which the 
government affords protection to his idea 
that all atoms can be represented by 
varying numbers of tetrahedrons. The 
germ of the idea appears to be that as there 
are about seventy elements known to chem- 
ists, and that the tetrahedrons can be 
grouped together in as many as seventy 
different ways, the latter can illustrate the 
former. This is theidea; the practice, the 
inventor shows, is not so simple. For in- 
stance, he says: ‘ Regular tetrahedrons do 
not fit exactly, but each tetrahedron is so 
nearly regular that it may be supposed that 
each of the elements were (sic) created from 
regular tetrahedrons in a plastic condition.’ 
This strikes us as a beautiful example of 
inventing facts to fit. a theory. We are 
glad to find that Mr. Edwards has not pat- 
ented atoms per se, but merely the form he 
thinks they take, together with a few names 
of elements, hitherto undiscovered, but pre- 
dicted by him. These are: icosagon, atomic 
weight, 10; z-odine, atomic weight, 215; 
and zadmium, atomic weight, 245. It will be 
interesting to watch the action for infringe- 
ment of patent which will result if any 
chemist engaged in research should have 
the temerity or the misfortune to discover 
either of these predicted elements. A litho- 
graphed diagram at the end gives the shape 
SCIENCE. 
[N. S. Vou. VI. No. 131. 
of thirty-two elements, with atomic weights 
made to fit; we are sorry to have to record 
the fact that many of these atomic weights 
are wrong, but then so probably are the 
shapes.’ 
THe Chemisches Centralblatt gives an ab- 
stract of a lecture by L. Wenghoffer, of 
Berlin, on the incandescent (Welsbach) 
gas-light. Among many points we note the 
following: Auer von Welsbach is not the or- 
iginal discoverer of the incandescent light, 
but deserves the credit of having brought 
the light to its present perfection and made 
it an industrial success. The oxids for the 
mantles must be chosen with great care, as 
well as their proportions, to attain the 
maximum brillianey. The best results are 
reached with about 99% thoria and 1% 
ceria. The presence of any other of the 
rare earths does not improve the light, and 
a greater or lesser proportion of ceria is 
detrimental. ‘Russium’ nitrate, the use of 
which has been recommended in the place 
of cerium, proved in one case to be a mix- 
ture of thorium nitrate with much cerium 
nitrate, and in another case to be a mixture 
of cerium andammonium nitrates. ‘Lucium’ 
oxid is impure yttria. The best source of 
thoria is monazite sand, and the price of 
thorium nitrate has fallen from $500 per 
kilo at the opening of 1895 to $5 or less at 
present. The cause of the low price is 
competition, and there is no probability 
that the supply will diminish. The source 
of the cerium is the by-product of the 
thorium manufacture, and the price of its 
nitrate is steady at about $50 per kilo. The 
bath for saturating the mantle is a 30% 
aqueous solution of thorium and cerium 
nitrates in the proportion of 99:1. 
From experiments on the action of ammo- 
nia on mercurous iodid, Maurice Fran¢ois, in 
the Journal de pharmacie et chimie, is led to the 
belief that the dark product formed by the 
action of ammonia on calomel is not a 
mercuro-ammonium compound, as has been 
