The Milan exchange. (Milan, Gibson County, Tenn.) 1874-1978, 1879-07-10
MECHANICAL AND SCIENTIFIC.

The Russian society of hygiene pro-
poses to print books in white letters on a
black ground, in order to check the in
crease of myopy in scholars.
Out of three dozen samples of wall
paper examined by a London chemist,
scarcely half dozen were found to be
free from arsenic. The presence of the
poison was not confined to the green
papers. The light blues and somber
browns were among the worst speci-
mems.
A simple but practical test for fire.
damp in mines is suggested by MN.
Mallard and LIE Chatellier. 1t is to
keep hydrogen lamp burning in each
gallery. The intense heat OF the fame
enables it to consume ire.dsmp, the
presence of which it detects by the blue
aureole, when in proportion 30 low as
OPS per cent.
In building chimney put quantity
of salt into the mortar with which the
1ntercourses of brick are to be laid.
The effect will be that there will never
be any accumulation of SCOT in that
chimney. The philosophy is thus stated:
The salt in the portion of mortar which
is exposed sbsorbs moisture from the
atmosphere every damp day. The scot
thus becoming damp, tails down in the
fireplace. This is an English discovery.
1t is used with success in Canada n.
Y. Express.
g. E. Davis, in dealing with the SUBJ
ject of boiler incrustations in recent
paper, says that many nostrums had
been bro ught forward SIS preventives
which were absolutely worthless, if not
positively injurious. After many trials,
he was convinced that, IS all boiler.sc8les
were principally composed of sulphate of
lime tribasic phosphate of soda, the
"tripsa" of commerce was the best of all
preparations, as it absorbed the carbonic
acid in the water, and, acting on the
sulpnate of lime, precipitsted it with
the mud to the bottom OF the boiler,
whence the deposit can be removed
easily. a. a
For all mixtures of wool with shoddy
the best and longest merino woods are
now regarded, it appears, as the most
profitable. because they "carry" more of
the short fiber of the wool substitute.
1t is singular, too, what diversities of
use at present characterize this and
other descriptions OF wool, in the man
ufacture of many o the popular fabrics.
Thus, thin wool coatings are made from
the medium to the finest merino woods I;
ladies' fancy cloaking, from the finest
long merino woods, and, in the case of
of some varieties, of mohair, or the wool
of the Angors goat; and the finest long
merino combing woods are employed for
gentlemen's worsted eeatings For GER
tain varieties of delsines, eoburgs and
csshmeres, ladies' dress goods, with cot
ton warp, medium long merinos sre used;
for ladies' "Caledonian" cioakings, q
limited use is made of mixtures of sne
long combings; Italian cloth for Innings,
mohair lusters, lsstings; dsmssks for
furniture covering, curtains and table
cloths; reps for furniture and curtains:
webbing for reins and girths, and
for suspenders; bunting for Gags, military
sashes, picture cords and tassels, clouds
or nubias. Ristori sbowls braids and
binding, all use long English combing or
Canada wool. This shows how prom
inently merino wool enters at the pres
ent time, into the composition of the
various makes of wooden goods.