Daily globe. [volume] (St. Paul, Minn.) 1878-1884, 1880-06-20
SCIENTIFIC.

hHOuouHu POuuuS, OuCo dppueu, WILL JUST
break q bar of iron or steel, a stress very
much less than fifty thousand pounds viii
break it if repeated sufficiently often. Tests
made in this direction go to show that rup-
ture may be caused by succession of
shocks or impacts, none of which alone
would be sufficient to cause it. Wrought
iron will crystalline by repeated blows in
service and become weaker than cast iron
iron exles, the piston rods of steam ham,
mers and other pieces of metal that are sub
ject to continuously repeated shocks, inva-
riably break after certain length of SER
vice-in other words, the life" of the
metal is limited. Iron rods in bridges some
times crystalline and break, although the
rods in most of the iron bridges of the pres
ent day may have five, fifty, five hundred
years of life yet allotted to them-due to
their factors of safety. It is well known
that wrought iron, subjected to continuous
vibration, assumes a crystalline structure,
and its cohesive powers become much de-
Perforated.
The new and novel system of electric
Lighting, known sas Werdermann's, has
just been satisfactorilN tested in London.
Nine lights in the same circuit were kept
going by Gramme dynamo-electric ma
chine of the old type, driven by a verti-
cal engine and boiler The light was very
steady, and, though no shades or globes
were used, there was no unpleasant effect
produced ON the eyes. The lamp consists
of hollow metal tube, through which the
carbon pencil is gradually fed up as con-
sumed, being kept just short of contact
with a carbon disl-the latter balanced SO
as to fall down in case the pencil should
not, from any cause, be fed up sufficiently
to the disk. In this case, contact with
to pass through that particular carbon,
calls attention to the defect. Four inches
of carbon are consumed in an hour,
ct a cost of twelve cents for twenty
inches, and the nine lights only require
four and one-half horse power. In re-
spect to cost, therefore, this new light is
found to compare favorably with other az
engagements.
BY means of highly ingenious carpet
weaving machine, recently introduced, it IS
found practicable to produce carpet-a
velvet pile, in appearance and quality said
to be a most luxurious article-at very low
cost. The worsted yarns forming the face
OF the carpet are wound from ordinary bob
bins on long bobbins the width of the car
pet, the colors being arranged by comb as
the pattern requires. The ends are passed
through metal tubes for delivery, and the
bobbins in proper sequence are then fixed
on an endless chain over the loom. AS this
chain revolves, metal clips seize each bob
bin in turn, take it of the chain, and dip
the ends of worsted among the warp threads
of the carpet, where they are at once firmly
fixed, and circular knife cuts off the
worsted at proper level. The bobbin is re-
turned to the chain, and the succeeding one
dealt with-and SO on, continuously.
An ingenious system of winding gear for
coal mines has lately come into use in Ger
many and France, the chief feature consist
ing in doing away with the ordinary draw
and the great weight of rope, which, in
deep mines, are very great strain upon the
engine. The cages are attached one to
each end Of the winding rope passing over
the head gear pulleys and over a winding
pulley, which takes the place of the draw
balance rope of the same weight as the
winding rope is also fixed to the bottom of
each of the cages, this balance rope hanging
freely in the shaft, and the lower end being
allowed to dip into the sump at the bottom.
By this arrangement, however deep the
shaft, the ropes and cages are always bal
anced, and the engine, in winding up, has
only to overcome the weight of coal in
the tubs and the friction of the working
parts.
A CONTINUANCE has been brought forward
by Bordeaux inventor for regulating with
exactness the speed of machinery. There
Is spindle, TO which rotary motion is i'm
parted by the machine to which it is at
tached, and on this spindle is fitted sliding
cone, and under the latter is a cross-head,
bearing bent and counterpoised arms jointed
thereon. When the spindle is revolved by
the machine, the arms are thrown outward
at their lower extremities, but impinge upon
the cone with their upper extremities. By
means, then, of their varying friction on the
cone, which of course increases with the ve-
locity of the motion of the spindle, the
speed of the latter is easily and accurately
controlled, and its means and that of the
machinery with which it is connected by
gearing wheels.
By admitting heated water direct into the
small cylinder of compound engine. it is
claimed by French inventor that double
the quantity of steam is generated with the
same amount of coal-the cause Of this re.
suit lying in the fact that the formation OF
steam no longer takes place in the boiler
but in the cylinder of the engine, and, this
being the case, the disturbance inseparable