Mexico weekly ledger., 1891-01-08
SCIENTIFIC POINTS.
THE POTATO DISEASE.

1hE foIAlO blSEAsE.
In Denmark, some interesting
and, perhaps, very valuable re-
searches into the potato disease
have been made by Prof. J. L.
Jenson. The disease is found to
consist of a fungus. whose spores
sre..carried by the wind, and which
first attacks the foliage of the
plants. Itspreads to the tubers in
about seven days by spores washed
down from the stem and foliage.
Considering these facts, it was
thought that the tubers might be
protected by moulding the soil into
a broad ridge, 3 or 4 inches high
and 10 or IL inches wide, after the
first wedding, and a further earth
ing up on one side only-causing
the plants to bend SO that the
spores would fall away from the
ridges-within seven days after the
appearance OF the disease on the
foliage. Some $50 farmers are said
to have experimental in this way,
with these astonishing results
Where no moulding or earthing up
was done. the per centage of dis
eased potatoes was "a; where the
moulding was imperfect, II; and
where the moulding was perfect,
only. Infection during harvest
was prevented by allowing the
tubers to remain in the ground for
month after the whitening of the
ops.
COLD WAVES.
A cold wave Is defined by Prof
7. Russell as fall of temperature
in twenty -tour hours of twenty de-
grees over an area of SO, 900 square
miles, the temperature in some
part of this area descending to SO
degrees. Between 1880 and 1890
no less than 69l cold waves were
recorded in the United States. In
the great cold wave of January II,
1882, the fall of twenty degrees ex-
tended over an area of 1,101 900
square miles, and the tall of ten
degrees included 1929 900 square
miles. In six cold waves of
the ten years the area of the fall
of twenty degrees was more than a
million square miles. Cold waves
follow day after an area of low
pressure, or occur to the southeast
of an area OF high pressure, reach
ing their greatest extent when both
conditions are present.
NESTS FOR GERMS.
| The impurities that collect un.
der finger nails have been investi.
gated in the meteorological labor.
; atories of Vienna. The matter OBJ
tanned in 7S examinations was
. placed in culture solutions, anC
gave 36 kinds of micrococci, Is O
, bacilli, and 3 of sarcinae. CIeanli
ness of the nails is especially nee
essary for all who come near /.
wound, and for those who live in ,
, neighborhood where an epidemic
. prevails.
REMARKABLE PREsERvATIvE.
A Belgian chemist has found tina
f the green tar left after extractin,
Y the oil from the white bark of tn,
birch will effectually preserve evel
t the most delicate textures from de
s cay. 1t yields neither acid nor al
/ kaloid, is remarkable fluid in alco
l holic solution ,and when once drie,
resists even the action of alcohol
A NEW IDEA.
A recent contract provides TO
> street lighting in Paris on a move
plan. Power is distributed by tn
=, compressed air system to a gres
nu nber of some motors, each c
which supplies electricity for
small number of lamps.
:. The trotting interest continue
. to increase, and is growing at sue
a pace as can scarcely be compre
. hended by Its most sanguine adve
; Gates ten years ago. A successfr
. sire, or one with a fast record, WI
= bring a little fortune when offere
" for sale. The love of the fast tro
ter is not confined to any one SCI