Science of the International Exhibition. 257 
deserves particular notice. A single ingot of pure platinum, weighing 
8200 ounces, Troy, was the most conspicuous object in the case, and af- 
forded a good illustration of the progress which this branch of metal- 
others, The fusion of this mass of platinum was effected in an iron box, 
which was lined with small pieces of lime, and covered with a lid of similar 
sy 2 . . . 
and a pyrometer for indicating the variations of heat lers. 
of these articles was said to possess, in design and construction, several 
points of superiority over any similar apparatus hitherto made her 
objects of interest were platinum tubes, soldered with the same metal, 
and a er, plated with platinum, showing that the many dif- 
ficulties attending the produetion of these articles have now - 
cesstully overcome. T me case contained an ingot of pure iridium 
"S gold pens as advantageously as grains of larger size. Palladium, 
thodium, and ruthenium were al i 
Mens, in quantities never before seen. Many other rare and interesti 
Substances were exhibited in this case, among which may be mention 
various salts of uranium, boron and silicon, fused and crystallized, which 
Deville himself had prepared by the process that bears his name. 
Aluminium.—Aluminium, also, was well represented in the Exhibition, 
Vaniety eben objects. e of the more noticeable of these 
Were philosophical instruments, for which this metal, from its lightness, 
Strength, and difficulty of oxydization, seems so well adapted. Various 
alloys of aluminiu i j 
ays. 
aluminium tubes, in the French department, indicated that the difficult 
Problem of rding 
to the exhibitors, zine was the solder used, and the operation was per- 
formed m an atmosphere of hydrogen. 
op eereury. Mercury and its ores were well represented in various parts 
the Exhibition, the specimens of cinnabar from Almaden in Spain, and 
ne the New Almaden mines of California, being ea conspicuous, 
these Metals, were also fully represented, but the collections contained little 
