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POPULAR SCIENCE REVIEW. 
by Messrs. Howard, of Bedford, and a boiler of this kind recently placed 
on a steam-tug (the Fairy Dell) has been successfully worked at a pressure 
of 150 lbs. per sq. in. This, for marine purposes, is a very unusually high 
pressure. 
Archimedian Screw for Lifting Water. — Mr. Wilfrid Airy has communi- 
cated a very interesting paper on this well-known contrivance for pumping 
purposes. He has greatly improved the screw, and made it more easy of 
construction by making the diaphragm which forms the spiral chamber 
part of a developable surface instead of part of a true screw surface. 
Bound a solid core he winds a plane sheet of tin or other metal, and retains 
its inner edge in a spiral groove. The plane then takes a determinate 
position, not at right angles, but inclined to the central core. The whole 
is then placed in its usual cylindrical case. The developable screw threads 
are not only more easily constructed, but they make a more efficient 
machine than the true screw threads. Mr. Airy's experiments show that 
the efficiency of the screw under the most favourable circumstances may 
reach 85 to 88 per cent. 
MEDICAL SCIENCE. 
Inca Skulls. — It would appear from a letter of Herr Gratian, of Bruns- 
wick, to Chevalier von Haidinger, of Vienna, that the above subject has en- 
grossed the attention of the former of these two savans. The following is 
an extract : — “ With regard to my palaeontological researches, I beg to 
inform you that they are at present in a somewhat modern direction. The 
exploration of beds containing fossil bones^ especially of the period of the 
mammoth, the cave-bear, &c., as well as the search after implements of the 
stone period, combined with cave-studies, form now my, chief occupation. 
I have here explored a bed which has already yielded interesting results. 
The acquisitions of last year include two Inca skulls from Chincha Alta, 
which are in a condition quite as described by Morton, and are especially 
distinguished by the vertical descent of the occipital bone. These skulls 
were, besides other curiosities, presented to me by the commander of the 
North German frigate Neptune, who obtained them at the Huacas. There 
is a peculiar interest attached to them in as far as these skulls were brought 
to the surface in consequence of the earthquake on the Peruvian coast, 
which happened in the month of August, 1868.” — Mittheilungen der Anthro- 
pnlogischen Gesellschaft in Wien. 
Cancer of the Lymphatics. — Dr. Whitall, who has devoted some atten- 
tion to this subject, states that in a case which he lately examined after 
death, most of the lymphatic glands, the left breast, and the surrounding 
indurated tissue, contained an abundance of fibrous tissue, in which were 
embedded free nuclei and nucleated cells, of various shapes and sizes. In 
some of the glands, and in a portion of the pancreas, the cells predominated 
over the fibrous stroma. The central portion of the various growths was in 
an advanced state of fatty degeneration ; in some places scarcely anything 
but fat was discovered ; in others the cancer-cells were more or less filled 
with oil-globules. Portions of the pectoral muscles were reduced to mere 
