SCIENTIFIC SUMMARY. 
421 
Rotation of Saturn . — Professor Hall, from observations of a white spot 
just below the ring of Mars, finds the planet’s rotation-period to be 
10 h. 14 m. 23-8 S. + 2-30 s. 
Sir W. Herschel’s estimate was 
10 h. 16 m. 0-4 s ; 
the estimate commonly described as his latest, viz. 10 h. 29 m. 16*8 s., 
never having been given by him at all, but being in reality Laplace’s 
theoretical estimate of the period of the ring’s rotation. 
Rhenomena for the Quarter . — The most interesting phenomena during 
the next quarter will undoubtedly be the close approach of Mars and Saturn, 
at 4 a.m. on Nov. 4 : Mars will be 11' north of Saturn. Neptune will be in 
opposition to the sun on Oct. 29, at 11 a.m. Venus will reach her greatest 
easterly elongation on Dec. 11. Mercury reaches his greatest westerly 
elongation on Oct. 12, his greatest easterly elongation on Dec. 25. 
CHEMISTRY. 
Davyum — Sergius Kern, of St. Petersburg, has sent to the 11 Comptes 
rendus,” 1877, lxxxv. 72, a short notice on the occurrence of a new metal 
belonging to the platinum group, to which he has given the above name. 
The new element occurs in a specimen of native platinum, doubtless from a 
Russian locality ; it is not stated, however, whence it was derived. The 
material which he had tc work upon possessed the iollowing composition : — 
Platinum 
80-03 
Iridium . 
9-15 
Rhodium . 
0-61 
Osmium . 
1-35 
Palladium 
1-20 
Iron 
6-45 
Ruthenium 
0-28 
Copper . 
1-02 
Davyum . 
0-045 
100-135 
600 grammes of the native alloy were treated by the method devised by 
Bunsen for the separation of the metals, and the mother-liquors remaining 
after the removal of rhodium and iridium were treated with an excess of 
ammonium chloride and nitrate ; a dull red-coloured precipitate was formed 
by these reagents, and when calcined it left a grey mass resembling spongy 
platinum. When heated in the flame of the oxyhydrogen blowpipe it fused 
together, forming a little bead, having the colour of silvet and weighing 
0 27 gramme. This is the new metal, which is stated to be hard at ordinary 
temperatures and malleable at a red heat, and to possess the specific gravity 
of 9*385 at 25° C. Davyum is easily acted upon by aqua regia, but resists 
in a marked degree the action of boiling sulphuric acid. Potash throws 
