The Cincinnati daily star. [volume] ([Cincinnati, Ohio]) 1875-1880, 1878-02-21
SCIENTIFIC.

the discovery of new means OF working
them, especially where positive accuracy
is required. Steel cutters may not hold
their edge sufficient time to traverse
the full extent, of face on substances
30 rigidly hard, therefore it is important
that substitute be found of such dura-
bility as to retain its cutting edge intact,
producing the same trueness and accur-
acy of fsurface at the end of the work as
at the commencement. Such a tool,
when known to exist, will no doubt
prove a valuable acquisition, and be ca
gerly sought for. To obtain tool of
this description, the Societe d'Encour-
agement pour Rationale, of Paris, has
generously offered one of their largest
prizes to be awarded in 1877, for the ar
tificial preparation of compound black
diamond-commonly known by the name
of bort or carbon ate-for obtaining there
by powerful means of action of work
ing hard metal substances, &C.; this
prize being open to inventors in all coun-
tries.
ONE OF the most remarkable applica-
tions of photography is that by which it
is now made to register, and in the most
accurate manner, the mechanical action
of the human heart. Tie device by
which this result is attained is, indeed,
triumph of inventive skill. 1t consists
of thin india-rubber bag, to which a
short glass tube is attached; sufficient
mercury is poured into the apparatus to
fill the bag and portion of the tube,
and the instrument is then placed over
the heart of the person to be examined.
Arranged in this manner, every pulsa-
tion of the heart is indicated by a cores
ponding movement of the mercury in
the tube, and, by suitable Photographic
apparatus, provided with a moving SEN
sitive slip of paper, a perfect registra-
ton of the extent and rate of the pulsa-
tions is obtained. The interesting fact
is made known by this process, that the
fall of the pulse sometimes takes place
in successive horizontal lines and some
times in ascendant lines, the column re-
ascending two or three times before fall
ing altogether.
For LINES PARALLEL to the sides of the
drawing board, says the Technologist, the
L square is the best possible parallel rul-
er, and may be used in conjunction with
set square of forty-ive degrees for inter
and similar lines. The set-square of
sixty degrees by thirty will give increas-
ed facilities in setting out many orna-
mental geometric forms; L square
with shifting head is also very useful !,
but as ordinarily made it is clumsy For
parallel lines not falling within the
range of the and set square, the best
tool, in the opinion of many, is the roll
ing parallel ruler; this is more quickly
set to any two points, and more cleanly
in use than any other form. A set square
and straight-edge are used by many,
but they are more easily got out of place
and soil the paper. Set squares and Z
squares should be French polished, and
they can easily be cleaned.
A FRENCH CHEMIST has ascertained
that carbon exists in carburetted iron, in
various proportions Steel contains seven
to ten one-t -thousandths parts when hard, ,
ten to fifteen soft Pig iron contains
two or four one -hundredths, and some
times even five. The quantity is difficult
to settle. as it can only be ascertained in
analysis by the difference with manga
nese, silicium, phosphorus, sulphur, and
= chromium. The average of the results
is "A. When gray, the iron has given up
its carbon in the form of graphite, but
no appreciabIe difference is found in the
quantity of carbon in gray and white
pig. In all cases, if the real combination
of iron with carbon be admitted, it takes
place then-five equivalents of iron for
one of carbon. But, whatever the de-
gree of temperature may be, these ex-
periments show it to be impossible to
make more than five per cent. of carbon
enter the iron.
PROF. MALLET, publishes an interes-
ting account of his examination into the
various causes that operate to retard or
accelerate the earth's daily rotation.
He takes into account all the operations
at work upon the earth's surface, such
as the flowing of rivers down hill into
the ocean, the carriage of great masses
of earth, as mud, from the upper sec
tions of the globe to the bottom of the
ocean, the fall of rain drops, the flow Of
rivers from low to high latitudes, and
all other seeming insignificant causes.
His conclusion is-ditfering in this form
some very distinguished scientists-that
there is no reason for supposing the re-
tardation of our globe, by tidal friction,
whatever may be its actual amount, can
go on unchecked until the earth is