SCIENTIFIC SUMMAKT. 
101 
METALLUEGY, MINEEALOGY, AND MINING. 
Didymium a Constituent of British Minerals. — Prof. A. H. Church, M.A., 
E.C.S., writes to the “ Chemical News ” (September) to say that Didymium 
was first discovered in a British mineral by Mr. C. Greville Williams, F.R.S., 
in the year 1865. This fact is recorded in the Chemical News,” vol. xii. 
p. 183. The mineral containing this rare metal was described by me as 
< a new l^ritish mineral containing cerium.’ Analyses proved it to be a 
hydrated phosphate of the cerium metals, the latter, calculated as cerous 
oxide, constituting no less than 51*9 per cent, of the mineral. Specimens of 
this mineral may be seen in the British Museum, Mineral Case, No. 57. It 
is, however, very rare, and I hesitated to sacrifice the specimens which I 
possess in order to attempt a precise estimation of each of the cerium metals 
present. It occurred in a Cornish copper lode on quartz and killas. A 
concise description of the species will be found in Dana’s ‘ Mineralogy,’ 
p. 555 (5th edition, 1868).” The above remarks were suggested by Mr. C. 
Horner’s note on the presence of didymium in pyromorphite (^‘ Chemical 
News,” vol. xxvi.) The occurrence of cryptolite in certain British, as well 
as foreign specimens of apatite has been ascertained. Now as cryptolite is 
an anhydrous phosphate of the cerium metals, it may be considered that the 
discovery of this species in apatite is equivalent to the detection of didy- 
raium in that mineral. I must say I have failed to find even a trace of 
cryptolite in the true asparagus-stone, the beautiful greenish-yellow crystals 
of apatite, from Juniella, in Murcia, Spain. Mr. Horner’s discovery of 
didymium in pyromorphite will naturally lead to the search for the other 
cerium metals in that mineral. 
What is American Sterling ? — This is the name which the manufacturers 
have given to a new alloy whose construction is at present a secret. The 
“ Scientific American ” (October 26) says that a company has been recently 
formed in the United States for the introduction of this alloy, termed 
American sterling.” The composition is as yet unpatented, but results, 
drawn from a series of careful tests and experiments, point plainly to the 
fact that the new metal is not only a discovery of great importance, but to 
all appearances calculated to revolutionise a large and flourishing branch of 
industry. In its crude state, this new alloy resembles nickel; but after 
being worked up, it is almost undistinguishable from silver. Unlike the 
latter metal, it does not tarnish and is unaffected by sulphurous vapours, so 
that it is eminently adapted to replace silver, Britannia, or the ordinary alloys 
in the manufacture of table ware. Articles of food have no action upon it ; 
alkalies produce a temporary tarnishing, w'hich may be immediately removed 
by a slight rubbing with the hand. Made in the form of cutlery, the aUoy 
possesses none of the disadvantages of steel or plate ; it takes a keen cutting 
edge, requires little or no cleaning, and is unaffected by ordinary organic acids. 
Knives made from it show no black edges after short usage, as is the case 
with plate, while they can be ground or sharpened whenever necessary. 
The metal is unusually flexible and tenacious ; a table fork made from it was, 
in our presence, twisted into a perfect knot, without showing the least flaw 
or intimation of breakage. 
