The Bolivar bulletin. [volume] (Bolivar, Hardeman County, Tenn.) 1865-1888, 1879-07-17
MECHANICAL AND SCIENTIFIC.

The Russian society of hygiene pro-
poses to print books in white letters on
black ground, in order to check the in
crease of myopy in scholars.
Out of three dozen samples of wall
paper examined by London chemist,
scarcely half a 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.
Mallsrd and LIE ChatelIier. It is to
keep a hydrogen lamp burning in each
gallery. The intense heat OF the flame
enables it to consume fre-damp, the
presence of which it detects by the blue
aureOe, when in a proportion so low as
OPS per cent.
In building chimney put a quantity
of salt into the mortar with which the
1ntercouTses of brick are to be laid.
The effect will be that there viii never
be sny accumulation of SCOT in that
chimney. The philosophy is thus stated:
The salt in the portion of mortar which
is exposed absorbs moisture from the
atmosphere every damp day. The SCOT
thus becoming damp, falls down in the
fireplace. This is an English discovery.
1t is used with success in Canada.--TN.
Y. Express.
G. E. Davis, in dealing with the SUBJ
ject of boiler incrustations in a recent
paper, says that many nostrums had
been brought forward as preventiVea
which were absolutely worthless, if not
positively injurious. After many trials,
he was convinced that, SIS all boiler-scales
were principally composed of sulphate of
| lime tIibasic phosphate OF soda, the
-" tripEa" of commerce was the best of all
preparations. as it absorbed the carbonic
acid in the water, and, acting on the
sulphate of lime, precipitated it with
the mud to the bottom OF the boiler,
whence the deposit can be removed
easily.
For all mixtures of wool with shoddy
the best and longest meTino woods are
now regarded, it appears, as the most
profitable. because they ''csrry" 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 Of the popular fabrics.
| Thus, thin wool coatings are made from
,
ladies' fancy cloaking, from the finest
| long merino woods, and, in the csse of
of some varieties, of mohair, or the wool
of the Angora goat; and the finest long
merino combing woods are employed for
gentlemen's worsted coatings. For GER
tain varieties of delaines, coburgs and
cashmeres, ladies' dress goods, with cot.
ton warp, medium long merinos are used;
| for ladies' "Caledonian" cioakinQs. q
limited use is made of mixtures of fine
long eombings; italian cloth for Innings,
nOhair lusters, lsstings; damasks lol
furniture covering, curtains and table
cloths; reps for furniture and curtains
webbing for reins and girths, and
for suspenders; bunting for flags, military
sashes, picture cords and tsssels, clouds
or nubias. Rstori showls braids anG
binding, all use long English combing OF
Canada wool. This shows how prom
inently merino wool enters at the pres
ent time, into the composition of the
various makes of woOien goods.