The University daily. [volume] (Morgantown, W. Va.) 18??-????, 1880-06-09
SCIENTIFIC NOTES.

The great question Of the day for ply
sicians to study, says Dr. S D. Gross. of
Baltimore, Is preventive medicine, the hy-
giene Of our persons, our dwellings, our
streets; in 4 word, our surroundings.
whether in city, town, hamlet Of country;
and the establishment Of efficient town
and State boards ofhealth, through whose
agency we shall be better able to prevent
the origin and fatal effects Of what are
known as the zyrnotic diseases.
Sit w. Thompson. who IS one of the
most prominent Of the scientific workers
in England, makes some sensible suggest
ions about improvements in lighthouses
ia a letter to The Londsx Times. He
recommends: Cd A great qnickening Of
all revolving lights. ~ The application
Of group Of dot-dash signals to every
fxedlight 80 The abolition Of color as
! distinction lighthouse lights, except
for showing dangers, channels and ports
BY red, white and green sectors. His
proposal IS to distinguish every fixed light
by rapid group Of two Or three dot-dash
eclipses.; the dot Of about half ascend
duration, the dash three times as long
with intervals Of light, about half alsecond
each, between the eclipses Of the group,
and Of five OF six seconds between groups
The distinction BY color alone ought to
be prohibited, he says, for all lighthouse
lights, on account Of its liability to be-
confused with ships and steamers side
lights.
OF about one hundred and twenty rel
volving lights on the English, Scottish
and Irish coasts there are in all eighteen,
in which the periods are ten seconds or
less, and the times Of extinction seven
seconds or less. In this quick revolving
lights, the place Of the light is not prac-
tically lost during darkness; the eye.
sweeping deliberately along the horizon,
with or without the aid Of a binocular, TO
pick up the light, " passes over less than
its own feld1of view within the period Of
the light, and thus finds it almost as
surely as if it were fixed. The system Of
dot=dash lights has also been strongly
urged for adoption on all sea going yes
sells, which would thus by the use Of the
Morse alphabet be able to interchange
messages at night with either passing
ships in mid ocean, or with lighthouses or
light ships along the coast. l
Portland cement was discovered in En-
gland in 1924, and little change has taken
place in".its manufacture during half a
century. In making it, the chalk and
clay, Of which it is Composed, are tho
roughly mixed in a pug or washing mill
with large proportfonfof water. After
being carefully worked, this liquid ''slur-
ny" is pumped q conveyed to the becks
or settling ponds, where the heavier por-
ton subsidies, leaving the water on the
top. The water being drawn off, the
substance at the bottom IS technically
known as slip" The slipis spread on
flats to dry, the requisite heat being de-
rived from coke ovens underneath The
dried material is then placed in kilns and
calcined. 1t is next ground by horizontal
millstones, and is then ready for the. mar
+ ket. - ! ri 551- #F
Several Improvements have lately been
introduced into the manufacture. One of
these consists Of a peculiarly construction
Of wet grinding for the washing mill, thus
doing away with the large amount Of
water required by the old process. By.
combining these two improvements some
English cement makers have obtained
very satisfactory results, making a better
article at a much cheaper rate, and proba-
bly5extending the sources Of theraw ma
'terial used beyond the chalk deposits and
the alluvial clays Of the tertiary period
The audiphone as invented by Mr..
Rhodes, of Chicago, consists of a disk of
Eebonite curved into place by strings at
the back. Several notifications have.
been suggested. Professor Colladon, Of
Geneva. recommends cheap substitute
. II the form Of \ strip Of elastic cardboard,
i fine kind Of yellow mill board with
smooth glazed surface. A sheet of this
material about IS inches long BY 10 in.
rhes broad yields results quite equal it's
said. if not superior, to the ebonite audi
phone. An English experimenter finds