1825.} 
New Cenient.=Al spatent has) recently 
been obtained for a composition of marble, 
flint, chalk, lime, and water, which is deno- 
minated Vitruyian cement, and when dry 
is eapable of being brought to a high state 
of polish. The proportions are one part of 
pulverized marble, one part of pulverized 
iiint, and one part of chalk, mixed together 
and sifted through a very fine sieve; to this 
is to be added one other paxt of lime which 
has been slacked at least three months. A 
suilicient quantity of water is to be added 
to make the whole into a thin paste, and 
in that state it is to be spread as thinly 
us possible overa coarse ground,and brought 
to a smooth surface by the trowel This 
cement when dry, may be polished with 
pulverized Venetian tale until the surface 
has become perfectly smooth and shining. 
_. Fossil Bones,— After the various geolo- 
gical. systems which have been framed to 
account for the different fossil remains dis- 
persed over the continents of Europe and 
Asia, we are scarcely surprised at any new 
liypothesis, unless it carry with it an ep- 
pearance of truth. A gentleman of the 
name of Ranking, in a recent publication 
of the highest merit, has stated as his 
opinion, that the remains of different ani- 
mals which have been found in coun- 
tries very remote from those to which 
they belong, have not been transported to 
their present localities by the action of a 
deluge, but are some of them the result of 
the. Roman sports in the amphitheatre, 
and of the great hunting, matches of the 
Mongols,. while the rest have accompanied 
the armies of these two nations, the mighty 
conquerors of the eastern and western 
world. .This is the outline of Mr. Rank- 
ing’s very able work, of which we shall 
give an abstract in a future number. 
Surveying Signals. — Asa signal to be em- 
loyed by night in grohesical and other simi- 
RP recions. a ball of lime intensely ignited 
and placed in the focus of a parabolic mir- 
ror (the ingenious invention of Lieutenant 
Drummond), will supersede every other. 
» In the last volume of the American Phi- 
losophical Transactions, a new form of 
‘signal to be employed by day is described, 
Oat is preferable to any except the helios- 
tal of Gauss at present in use. It consists 
of a. yessel of planished tin plates, the 
lower part bas the form of a truncated 
one open at bottom, whose height is 
inches, the lower diameter 17, the up- 
r, 14, . The vessel is, closed at the top 
y a, plate 3 inches in, diameter and ele- 
d five inches above the upper diameter 
the truncated cone; the intervening 
ace. is. enclosed by a tin-plate, which has 
in consequence also the form of a truncated 
« _a greater verticle angle than that 
ene Under favourable circumstances 
i ‘signals appeared 
» disk, often requir- 
f 4 Ass. Bilton tae eye. 
n in distances of from thirty to forty 
MLM. New Scrics,— Vou. IL. No. 9. 
Varieties. 
329 
miles they presented:a distinct illuminated 
point, when the sun was in such a position 
as to leave its rays reflected directly to the 
observer ; and the continuance of this re- 
flection is sufficiently Jong to admit of 
every necessary observation, As the point 
of reflection is not always in the direction 
of the centre of the signal, a reduction was 
used in America to correct the observed 
angle for the error arising from this cause. 
To perpetuate the recollection of the posi- 
tion of the signals larger truncated conical 
vessels of earthenware were buried, with 
their axes exactly corresponding with the 
axes of the signals. As earthenware is 
almost indestructible, it is probable that 
no monument equally durable can be ob- 
tained at so small an expence. 
_ Hardening of Stcel Dies.—In Franklin’s 
journal it is stated that Mr. Adam Eck- 
feldt was the first who empleyed the fol- 
lowing successful mode of hardening steel 
dies. He caused a vessel, holding 200 gal- 
lous of water, to be placed in the upper 
part of the building, at the height of forty 
feet above the room in which the dies were 
to be hardened; from this yessel the water 
was conducted down through a pipe of 
one inch and a quarter in diameter with a 
cork at the bottom, and nozzles of diffe- 
rent sizes to regulate the diameter of the 
jet of water; under one of these was placed 
the heated die, the water being directed to 
the centre of the upper surface. The first 
experiment was tried in the year 1795, 
and the same mede has been since pur- 
sued (at the mint) without a single instance 
of failure. By this process the die is 
hardened in such a way as best to sustain 
the pressure to which it is to be subjeeted, 
and the middle of the face, which by the 
former process was apt to remain soft, now 
becomes the hardest part. The hardened 
part of the die so. managed, were it to be 
separated, would be found to be in the 
form of a segment of a sphere resting in 
the lowest softest part as ina dish; the 
hardness of course gradually decreasing as 
you descend towards the foot., Dies thus 
hardened preserve their forms until fairly 
worn out. 
New Manufacture of Glass.—A patent 
has been granted in Franee to a M. Se. 
gnay, for a new method of manufacturing 
glass without the use of free alkali. The 
following is the process: take 100 parts of 
dried sulphate of soda, 656 parts of silica, 
and 340 parts of lime which has been ex- 
posed to the air; all these ingredients must 
be mixed with much exactness. The fur- 
nace and pots are to be heated till full red, 
when the mixture in small balls should be 
charged into the pot until the latter is fall, 
the mouth of the pot should then be 
stopped up, and with its contents intro- 
duced into the furnace, and as soon as it is 
per eve that the materials have sunk in 
the p re of the same mixture must be 
a re until the pot is filled with a melted 
