The National tribune., 1885-11-19
SCIENTIFIC CHAT.

A valuable crystalline coating for wood or pa
per may be obtained il IS stated. by mixing a very
concentrated cold solution of salt with dextrine
and laying the tbinnest coatng of the fluid the
surface to be covered by means of broad soft
brush. After drying the surface has beautiful
bright, mother of pearl coating which, in cOBSe-
quenee of the extrine adheres firmly to paper and
wood. The coating may be made adhesive TO glass
by doing it over with an alcoholic sheac solution
Suphate of magnesa acetate of soda, and SUI phi ate
of tin are among the salts which produce the most
attractive crystalline coatngs. Paper must first be
sized, otherwise it will absorb the liquid and pre-
vent the formation of crystals.
Watches may be sent for testing to the Kew
Observatory in London, and a certificate of excel
lence will be given but extreme is the accuracy
required that no watch can be marked first class
which varies as much rs one tick in 1900.
In Germany the inspection of pigs for trichne
Is more thorough than is generally supposed. The
Mediciniscte UochensctriH states that in one year
there were established in Prussia 2O636 official in
specting stations. Out of 100000 of the animals
examined 2,0tO We're trcbinous.
The Journal OBiciet, publishing the statistics
with regard to the population of France in 1854,
gives the excess of births over deaths as being rs
in 1881. and 81 $40 in 1850. Altogether there were
93 75S births and s5S 7si deaths In 80 depart
the deaths exceeded the births, the excess being
greatest in the districts where the cholera prevailed
though there was also slight excess in some parts
of Normandy.
Veterinary surgeons thinl, that the overdraw
check rein, by reason of muscular strain upon the
eyes. produces blindness in horses.
The Indian Medical Gdzette advocates the use
of condemned criminals for cholera experiments.
1t shows that from 800 to 400 persons are hanged
annually in India, and thinks these might be spared
the final execution should they survive the doc
tors doses. The criminals are said to have ex-
pressed a preference for the rope.
Various methods have been devised for treat
ing the surface of certain woods as to produce
the most perfect limitations possible of rosewood,
walnut ETC.; but some of the most attractive work
in this line is effected by simply spreading the
surface of the material concentrated solution of
hypermangate of potassa this being allowed to act
until the desired shade is obtained. Five minutes
suffice ordinarily to give deep color few trials
indicating the proper proportions The hyper
mangate of potassa is decomposed by the vegetable
fbers with the precipitation of brown peroxide of
manganese, which the influence of the potassa. at
the same time set free, fixes in durable manner
the ibers. When the action is terminated the
wood is carefully washed with water. dried, and
then oiled and polished in the usual manner The
effect produced by this process several woods is
really remarkable On the cherry, especially it de-
veops beautiful red color, which ressts well the
action of air and light.
DR. Richardson finds scientific basis for say
ing that cat has nine lives If cat and dog are
shut up together in lethal chamber, the cat sur
wives, average, three times long, and
sometimes nine times as long as the dog.