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Page: of 446
134 MINING AND SCIENTIFIC PRESS. {August 30, 1879.
Magnetic Strains in Iron.
A. §. Kimball, Professor of Pbysics in the
Worcester Free Institute of Industrial Science,
gives an interesting paper to the August number of the American Journal of Science, the object of which is to describe certain experiments
made by inducing a magnetic state in bars of
eoft iron suhjected to varying degrees of mechanical stress. As the result, we alwaye have
changes either in the form or dimensions of the
bar, similar to those produced by the mechanical stress previously applied, and therefore the
term “‘magnetic strain” docs not seem inapproriate. Some of the phenomeua hereafter to be
escribed have heen observed hy earlier investigators. These experiments have not been repeated with the expectation of detecting errors
in their work, nor of attaiuing a higher degree
of accuracy, but rather, to afford that valuahle
check which the reproduction of well settled
phenomena, with a new disposition of apparatus,
affords, both upon the accuracy of the instrument and the skill of the operator. }
Effect of Magnetization upon the Tenacity of
Iron.—The pieces of irou tested were pulled
* asunder hy a Fairbanks testing machine of 53,000 pounds capacity. The machine consists:
1, Of alarge platform scale; 2. of a powerful
gcrew-straining apparatus, driven hy a helt
from a shaft having eight changes of speed (the
motive power is a Corliss engine which runs
with great regularity); 3. an automatic weighing attachment to the beam, by which it is
kept constantly poised as the stress is applied
to the test piece.
The delicacy of this adjustment was such,
that when the testing proceeded at a suitahle
rate, the deflection of the heam from the zero
point did not indicate a stress on the test pieee
differing more than two pounds from that
ehown hy the position of the poise on the heam.
The scale was ‘“‘sensitive” to the addition of one
ounce when the platform was loaded with 4,000
pounds; and on the removal of the small
weight, the beam promptly returned to its normal position. The course of experiment was as
follows: Several pieces of the same kind of
iron, made as nearly as possible uniform in size,
were hroken in the machine. The alternate
ones, in the order in which they were cut from
the bar, were magnetized to saturation by a
helix, through which a constant current was
passing during the experiment. The heating
effects of the helix were slight, and prohahly
without influence. The tahulated results were
then compared, and from them the following
eonclueion was reached: A soft iron bar hae its
tenacity increased ahout nine-tenths of one per
eent. by magnetizing it to saturation.
Another series of experiments upon telegraph
wire gave 8.9 pounds difference hetween the
means, Seventeen pieces of wire were hroken.
A series of 10 wires, one-quarter of an inch in
diameter, gave an average of unmagnetized
Pieces, 4,532 pounds; of magnetized specimens,
4,572 pounds; difference, 40 pounds.
Some hundreds of pieces were hroken with
the same results, A magnetized piece always
proving etronger than the unmagnetized pieces
taken from the coil or bar on either side of it,
A few apparent exceptions to this rule showed
flaws in the tested pieces on close examiuatiou.
The average increase of strength in these ex periments is very near nine-tenths of one per cent.
In every case the strength of the unmagnetized
pieces was much more uniform than that of the
magnetized. In the ‘Philosophical Transactions of the Royal Society,” 1874, page 571, Sir
William Thomson predicts this result as a deduction from Mr. Gore’s experiments on electrotorsion,
Effect of Magnetization upon the Flexure of a
Soft Iron Bar.—Joule’s experiments upon the
changes in dimensions of an iron bar when magnetized, formed the starting point for this part
of the experimental examination in question.
He has shown: .1. That if an iron rod he compressed longitudinally, it will he slightly elongated upon being made a magnet hy a surround:
ing helix. 2, That the amount of compression
does not affect the magnetic extension so long
ae the magnetizing force remains the samc. 3.
That the same phenomena, in kind and amount,
occur in a har which is neither compressed nor
stretched. 4, If the har he suhjected to tension, the elongation, on making it a temporary
magnet, is diminished, and as the tensile etress
increases, the magnetic elongation diminishes
through zero and hecomes a shortening. 5.
Prof. Mayer has shown that, in the case of an
unstrained har, the first passage of the current
elongates the har more than any suhsequent
passage of the same current, and that the
second, third, and all suhsequent elongations of
the bar hy a constant magnetizing force, are
equal to each other; also that the shortening of
the har upon breaking the current is constant
and equal to the second elongation. These
facts, taken in connection with the common
theory of flexure, fairly indicate one or two
phenomena which will he found to attend the
induction of a temporary magnetic state in a
bar strained transversely. We see, from what
hae heen said, that the neutral axis, and all the
fibers on the concave side of the har which have
been shortened by compression, will be elonga‘ ted hy the action of the magnetizing force,
while the fibers of the har on the convex eide,
which have heen subjected to tensional strain,
will either be elougated hy a less amount or
will he shortened. As the result of this action
we may be tolerably sure that the har will he
straightened. It is much safer, however, in
this case, to proceed with onr investigation experimentally, since neither the theory of magnetic action in iron, nor that of transverse
elasticity, can be said to bave been fully developed.
The apparatus used in this part of the investigation was simple. A very rigid iron casting,
with supports for a micrometer screw, and the
ends of the iron rod to he examined upon its
upper eide, was placed upon the platform of a
Fairbanks ecale. The iron rod, carefully freed
from magnetism and enclosed in its helix, was
adjusted upon its supports so that the point of
the micrometer screw was just below its middle, The helix was made in two parts for convenience in loading the bar. The middle of the
bar supported one corner of a triangular platform, whose sidee were four, eight and nine
feet. The other corners of this platform were
supported upon points. This disposition of
apparatus proved very satisfactory. The load
upon the bar was easily and accurately determined hy the scales, while the stahility of the
triangular platform permitted the addition or
removal of weight without eeriously disturbing
the adjustmeut of the har. The micrometer
screw had 60 threads to the inch, and its head
was graduated to 300 parts. The unit of
measurement is therefore 1-18000 of an inch.
At first, contacts of the screw with tbe bar was
determined by an electric bell, hut the prohable
error of eetting the screw heing greater than
one division of the screw head, a more exact
method was sought. The following device was
finally hit upon, which gave results which may
be trnsted to one-half divisions, The iron har,
micrometer screw, and a telephone were put in
the circuit of a very weak Leclanche cell.
When the screw was turned up to loose coutact
with the har, the familiar boiling eound of a
too sensitive microphone was heard, which
ceased the instant firm contact was made. The
change from the loud boiling sound to silence
was abrupt and sharply defined. In the
writer’s experience this is hy far the most
reliable method of determining the contact of a
screw,
Agricultural oer at the Mechanics’
air.
The exhibit of agricultural machinery at
tbis year’e Mechanics’ fair is in some respects
hetter than it has been for several years. It is
true that we miss some of those who have been
prominent exbibitors at former fairs, and whose
goods we would like to have seen this year, but
there was increased effort on the part of others,
and the epace is all occupied. We are disposed
to call this year’s display hetter than nsual, hecause the machines are uot shown as “‘lay
figures,” but are rattling, rolling, thrumming
and roaring away, performing mimic duties
with all the precision and fullnese with which
they do actual work in the field, the erain barn
or the warehouse. This, of course, gives life
and interest to the agricultural department ; it
makes a noise in the fair world, and people stop
to look at it.
This change in the character of the exhibit is
due to the enterprise of Marcus C, Hawley &
Co., for they have in their space one of H. W.
Rice’s strawburning engines which, taking its
steam from the main hoiler, turns all the machines shown by the firm. This engine of Mr.
Rice’s is a piece of agricultural mechanism to
be prond of. It emhodies all his latest improvements, and it is finished in a style which justifies us in saying that it is the handsomest agricultural engine we ever saw. The hoiler ig
neatly lagged with colored woods, the iron work
tastefully painted and adorned; the hrass well
polished, and the machine in every way a model
of good workmanship. We have spoken
mainly of the finish, hecause the efficiency of
the engine for the uses contemplated has been
frequently remarked. The engine was helted directly toa large Gold Medal separator, which was
running very smoothly. By means of connter
shafts the engine was turning the geared parts
of a large header, a harley feed grinder, and a
ower cornsheller of Adams’ self-feeding pattern.
M. C. Hawley & Co.’s exhibit also included a
champion fanning mill, Buckeye mowers, and a
large assortment of plowe. There was also
within the enclosnre handsome epecimens of R.
I, Knapp’s side-hill plow, made at Half-Moon
Bay, San Mateo county, and of which we had
good accounts last fall from those who had used
it. It is certainly worth the examination of
hillside farmers. It is also well adapted for
use as a reversible plow on flat land.
Another firm making a varied and excellent
display of agricultural implements is Frank
Bros., of this city. Their exhihit is well arranged, and includes many standard and new
devices. _The most striking feature of the display is a Walter A. Wood’s self-hinding reaper
in full rig, which all those who do not have opportunity to see it in the field should certainly
examine with carte. Thisis one of the latest
triumphsin harvesting machinery, and is already
one ofthe most famous, Frank Bros. have also
a fullline of plowe, including the Browne gang,
and the Browne sulky, and single plows handsomely made and adapted to different requirements. They also show the McSherry grain
drill, the La Belle wagon, a hand cider mill, feed . o:
cutter, etc. We noticed also the Defiance cultivator, evidently a powerful implement and
adjustahle to a variety of cultures, The exhihit
in Banal is a very creditable one.
avid N. Hawley, another of our wellknown implement dealers, makes a display of
several popular implements, including the Newton wagon, Meyers’ excelsior gang plow,
meadow king mower, Arcbimedean: lawn mower,
etc, He gives considerable space to an exhibit
of scales adapted to all uses, beautifully finished,
and so far as we could test them, very accurately adjueted.
A novel device, which will attract mnch attention, is the fruit picker of L. H. Titus, of
San Gabriel, Los Angeles county. It consists
of a ladder mounted upon a light truck, and
beside it is a large circular hopper of canvas,
into which the fruit falls, and rolls into a hasket below. It seems well calculated to aid in
quick work, and to preserve the fruit from injury.
Another California made implement is Dalton’s gang plow, rade at the Pacheco foundry,
in Contra Costa county. It is well finished,
and seems to be well designed for effective
work. Many of our local shops are doing good
work in plowmaking, and the Pacheco foundry
is evidently one of them. ‘
The windmill features of the fair are maintained by the Iron Turbine wind engine, introduced to this State this eummer by D. E. Goldsmith, of 419 Sansome street. It has already
commended itself to many of our wind-power
users, both for its mechanical principles and
material employed in its construction, and bids
fair to become a popular machine.
There is a good show made of harrows of California manufacture. Gas-pipe harrows, folding and otherwise, are shown in good variety,
hut without the exhibitor’s name attached.
Another California harrow is named the
“‘Farmer’s Friend” or ‘Channel Iron Harrow,”
patented hy N. Beauregard, and ehown hy the
agents of J.Smith and R. Hoppe, of 318 Pine St.,
8. F. It is made in three independent sections,
with 24 steel teeth to each section. Thus it
adapts itself to inequalities in the surface. The
leading points of the harrow are the style of the
tooth and its manner of fastening to the bar.
As the tooth is grooved or channeled on two
sides, it is lighter than the solid tooth and yet
strong, and by its shape it keeps itself sharp.
Each tooth is held to the bar by an iron strap
tightened hy threads and nuts. Thnsit cannot
work loose, hut can be loosened aud lowered
easily when the point wearsup. These features
are novel, and seem worthy of examination.
Messrs. Hendry & Lennon show an object of
peculiar interest in the shape of the first iron
casting ever made in this State. It was made
in 1850 to replace a brokcu part on one of the
argonautic ships, and if it be viewed in connection with some of the massive casting now
turned* out fron: our foundries, one can get a
good idea of the progress made in iron founding
during the short industrial life of our State.
Messrs. Hendry & Lennon also make a show of
iron wheelbarrowe which is interesting,
Adjoining the agricultural implement departmeut, Mr. James, of Visalia, showe some of the
mechanical appliances of his one-track railway, which is now attractiug much attention
among those who are considering the construction of cheap railways. He seems to secure a
very effective and simple application of power
to the work of propulsion, and we trust the
value of his devices will soon he demonstrated
hy the construction of a working one-track line,
Norvecium.—A uew metal of the ahove name
has heen discovered in the nickel ores of the
island Otero, near Krage, in Norway, by Tellef
Dahll. The ore is calcined to remove sulphur
and arsenic; it is then dissolved in acids and
sulphureted hydrogen used as a precipitant.
The precipitate, free from nickel, is washed and
calcined. It is redissolved in agua regia and
precipitated hy canstic potassa, avoiding an excess, in which the oxide of norvegium is soluble,
The precipitation is not complete, a portion of
the new metal remaining in solution. The precipitate, a hydrated oxide, is emerald green. It
may be very readily reduced hy fusing with
charcoal in a crucible or hy a current of hydrogen. The metal is white, to a certain degree
malleable, as hard as copper and fusible at a
dull red heat. Its specific gravity is 9.44. It
is soluble with some difficulty in hydrochloric
acid, and readily in nitric acid, the solntion
being hlue, hut changing to green when
diluted with water. Assuming the oxide
to he NgO, the equivalent of norvegium is
145.95. Its salts are precipitated hy caustic
potassa, by ammonia and carhonate of soda, the
precipitate heing green and giving hlue aolutions.
Sulphureted hydrogen gives, even in very acid
solutions, a hrown precipitate insoluble in sulphide of ammonium, Before the hlowpipe, in
an “oxidizing flame, horax givesa green glass
which becomes hlue on cooling.
New Execrric Current RecuLator.—M.
Hospitalier, a French engineer, has invented a
new apparatus, which is composed of a resistance hohhin, formed of insnlated wire wound on
in a single layer, and having each turn stripped
of its insulating covering for about 0.4 of an
inch at the same spot; a curved lever, controlled
hy an electro-magnet at one end and hy an adjustahle spring on the other. This lever moves
forward or backward on the bare portion of the
bobhin if the current weakens or strengthens,
until the resistance is adjusted hy the decreased
r increased number of turns in the circuit, and
equilibrium is produced, The value of an apparatus of this kind for regulating the motion
of dynamo-electric machines is great, as much
of their utility depends upon steadiness of motion, 4
The Mineralogical Resources of New
Zealand,
In the way of mineral wealth New Zealand is
particularly rich, and promises ere many yeara
have passed to compete in the markets of tbe
world with her coal, steel and iron. The mining
world was lately not a little startled by a statement that was circulated through the papere to
the effect that the New Zealand government
had asked for tenders for the supply of 100,000
tons of steel rails to be manufactured in New
Zealand of colonial ores, There are vast resources of coal and iron in that country, and the
only difficulty encountered in producing for
such an order is the want of ekilled labor. Dr.
Hector, the Government geologist, reporting on
these resources, says :—‘‘ Extensive deposits of
ironstone are to be found in various parts of the
colony, and especially would I notice one which
I visited at Para Para, near Collingwood, Province of Nelson. I wes surprised to find such a
large amount of ironstone lying in euch huge
blocks upon the snrface of the ground as I saw
in that district. The out-crop of this deposit
has already been traced over an area of from two
to four square miles. The estimate I formed
wae that over 15,000,000 of tons of ore were
visible npon the surface, without delving into
the bowels of the earth at all. Practically, this
area appears to he almost inexhaustihle. From
the analysis and smeltiuge which have heen
made hoth at Melbourne and Dunedin, this ore
has been found to yield upon the average 507%
of pure hematite iron.” This Para Para ironstone field is only one of many such districts
that remain to he opened out in New Zealand,
and in close proximity to it are valuable coal
seams, and also an unlimited eupply of limeetone, s0 that there appears to be every reqnisite for the manufacture of iron and steel. Before leaving the subject of iron, we may just
hriefly refer to another source of supply of the
raw material, and, although it is not yet a commercial success, there appears to be every probability of that problem heing solved at no very
distant date. Thisis the huge deposite to be
found on the seashores iu certain districts
closely amalgamated with the sand. The sea
apparently sweeps over rich veins of ironstone,
for each receding tide leaves hehind it a large
contribution to the already monster hillocks of
sand and iron that have heen piled up on the
foreshorcs for ages past. The high specific
gravity of this combination is strongly apparent
when a handful is lifted and allowed to filter
through the fingers, and an analyeie has shown
that the combination contains no less than 70%
of metal, The smelting of this ore has not, however, heen as yet a commercial success, hnt with
such valuable deposits lying on tbe eurface of
the earth all over the district ready to the hand,
little eurprise need be experienced at the fact
that very little has been done in the way of experiments in order to eolve that problem and to
give those seashore deposits a rich commercial
value. As itis, the experiments that have been
made have discovered that metal produced from
this source ig most excellent for the manufac.
tore of edged toole and all kinds of whitework.
As to the coal deposits, there are seame from
two feet np to no iess than 54 feet in thicknees,
of coal of the hest quality, and which can be
used for all the purposes of manufacturing,
steam, gas, and domestic nses, whilst the area
appears to promise almost unlimited quantities.
Thus, the Waingerri coal field is estimated at
16 square miles, whilet the Haitangota ie eatimated to contain 100,000,000 tons, and numbers
of fields equally ae exteneive as these have not
been opened out yet. Dr. Hector, reporting to
the Government, saye the Green Island coal
field extends over 40 equare miles, and is connected with one of the mainlines of railway by
a short tramway. It is worked on the room
and rance system, the eeams being from 16 to
19} feet in thickness, and the coal a hrown eort
very useful for manufacturing purposes. He
also states that the Small Boller coal field contains upwards of 100,000,000 tons, and the seam
in this mine is 18 feet thick, of splendid coal,
adapted either for manufacturing, eteam, or domestic purposes. This Small Buller mine has
been opened about four or five years, hut has
not been much worked yet on acconnt of the
scarcity of labor, and also the high rate of wages
paid in the district. Coal also extends over
a very wide area in Auckland province, and a
report recently made concludes as follows:
Coal appears to have heen scattered pretty
plentifully throughout the colony, as I have
met with it in Otago, Canterhury, Nelson, Weatland, Anckland, and other parts of the colony.
Besides these, the mineral products of New
Zealand are gold, silver, copper, lead, mercury,
plumhago and snlpbur, the latter heing found in
very large quantities. As an experiment, some
50 capable workmen have just been selected in
the mining districts of the mother country, and
are abont to he conveyed to the colony by the
New Zealand government. A good supply of
lahor would undonhtedly secure the opening up
of many of the rich coal and iron districts of
the country, and with the Australian porte
within five days’ sail of New Zealand, and San
Francisco, and the Indian, the Chinese and
Jananese ports also within easy reach, there appears to be not the slightest douht that a good
market can be found for the produce,—Colliery
Guardian,