1885.] Scientific News. 1139 
only unsightly, but will, in process of time, ruin the mount. If 
the cell walls were not entirely dry when the cell was closed, it is 
plain that the process of shrinkage had not yet been completed, 
and that it is yet to occur to a greater or less extent. What is 
the inevitable result? The fluid within the cell is practically in- 
compressible, yet pressure is brought upon it.- It has no space 
within its container inte which it can retreat, and consequently 
it must force its way out of it. This it does slowly and gradu- 
ally. It may be some time before it is noticed, but it is bound to 
come. The cement gives way at its weakest point, and the fluid 
exudes—“ creeps” out. It is discovered, washed off and a fresh 
ring of cement applied. This puts off the evil day a while, but 
in a few months the process has to be repeated. Meanwhile the 
pressure is continuously exerted, and minute quantities of the 
mounting medium gradually infiltrate the walls at fresh points; 
the cement disintegrates, scales, and splits off. The remedy pro- 
posed is—Never use a cell until the cement walls are thoroughly 
dry and hard.—Nat. Druggist, April 4, 1885. 
EE 4°) 
SCIENTIFIC NEWS. 
— The two Portuguese explorers, Captain Capello and Com- 
mander Ivens, arrived at Cape Town on July 16th, and left again 
soon afterwards for Mossamedes, with the intention of returning 
to Europe via the Congo. They have traversed a region which 
no European had ever set foot in, as leaving Mossamedes in 
March, 1884, they reached Quillimane, on the eastern coast to 
the south of Mozambique, in May last, having traveled over 4500 
miles of territory, 3000 miles of which were previously unex- 
plored. They discovered the sources of the Lualaba, an affluent 
of the Congo, which has been so frequently referred to at recent 
geographical discussions. They also came upon a region which 
is extraordinarily rich in copper, this being the district of Yaran- 
ganga, situated between the Lualaba and the Luapula. They also 
made a discovery which may be of great use to commerce and 
science. It has often been remarked that the venomous African 
fly, the tsetsé, which did so much mischief to cattle in the south- 
east of Africa, and had almost extinguished trade between Dela- 
goa bay and the Transvaal, had totally disappeared of late. 
Messrs. Capello and Ivens found that this fly was still very abun- 
dant further north, and that, as had often been stated before, it 
was always to be seen where there were plenty ot elephants. 
Stanley, in the course of his travels, had observed the same phe- 
nomenon, and it follows, therefore, that the region explored by 
the two Portuguese travelers is rich in ivory —Lnglish Me- 
chanic, 
