The sun., 1898-01-23

sum. also reduced to a certain mesh. To tho ground
ores and gypsum is addcd water and the thorough
mixing or churnng OF the primal ingredients begins.
When this mixing churpng reduces the aud
gypsum TO the consistency Of clay, the matter u
taken out and moulded into any desired form and left
to dry which requires but avery time After tho
bricks sinbs have bee sufcicntly dry they
ready to be dumped into tanks other reccptaclcs
and chemical solution is turned and, tho matrices
being entirely porous, the chemicals permrate the
bricks carrying away in solution from 90 to 90 per
cent. of all gold In the ore.
still another theory Is advanccd-th.s time hy n
scientific writer In the Boston 7ranscript--in OK.
PLANTATION OF the singing sands, phenomenon char.
ncterizing certain shores and beaches. This theory
is based upon results obtained ty prolonged invCs.
tigation on the spot, I'm all kinds OF weather.
animation with good microscope. This showed that
the particles OF sand are nearly uniform In size.
mostly quartz. every one exhibiting tho sharp and
hackled edges and the sub fracture OF the
vitreous varieties and, all tho edges extremely
thin II is assumed that tho peculiar sound known
singing may he caused by the friction OF myrlads
of and edges, and ty the impinRny OF innu.
merahle parcies and tho swapping md fracture OF
their frail. brittle edges when the sand s violently
stirred The fact, too. that when the sand is wet no
sound comes forth is In accordance with the point
made viE that when wet there IL greater cohesive.
ness among the particles. just as between two wet
cling closer together when stepped upon rather than
rebound, as when dry, and. being surrounded with
cushion Of water. they thus lose their elasticity.
valuable communication in Dinolcr's Polytech.
nfsches Journal by Hans Gunther. takes tho ground
that the Objectionable efiorescence which makes its
appearance on brick and sandstone structures may
come from the clay. the water employed during tho
various stages the ashes pyrites OF the coal and
from the mortar The pyrtcs of the COAL he remarks
may certainly cause mischief. especially because
practice Is commonly in favor OF continuous ring
kns which work with plenty OF oxygen. while in the
old periodical kilns the atmosphere
frequently reducing that but little suphuric
acd was formed. Again. tho presence OF
suphurc acid favors tho production OF red colored
bricks, for IL decomposes tho yellow ironlme sill.
cate. More Importance however, ia attached by
Gunther to tho pyrites in the clay and to chemical
interaction between brick and mortar In pursuing
the latter inquiry he found that certain bricks
mained quite smooth when piled up, and soon be-
came covered with effiorescences when used with
mortar that proved perfectly harmless to other
bricks. Almost all clays contain pyrtes which, in
the presence of magnesia, give rise to immediate
eforescenoes but in the presence OF lime only after
decomposition with the ak allies OF the mortar.
The making OF ships' masts Is one of the nautical
Industries which, on the OF economy and
strength, has undergone total transformation-the
placed by what is termed the buit.up mast-made.
that is, of a number OF pieces The primary advan.
tage claimed in this case is that It overcomes the
dif1culty Of obtaining solid stick OF suitable dmen.
sions for mast absolutely free from blemsh while
in making the built.up mast-composed OF q number
of smaller peces-t is easily possible select only
perfectly sound material. The usual method in this
style Of construction has been that Of q spindle-a
big square timber forming the centre heart-the
round OF the mast being formed by slabs laid the
sides OF the SPINDLE these parts not always being
single piece each Sometimes, also. the spindles
length is composed Of two three pieces scarved or
spced together. and perhaps the slabs scarved.
though not brought opposite the in the spin.
die. The finished stick. banded with hoops of iron.
being subject to decay give place. necessarily to the
next improvemcnt-tubes Of iron.
With view to determining the efficiency OF
dredging appliances in dealing with finely divided
gold the following investigation made.
ported in New Zealand journal. sample of nne
gold from an electric company dredges. about two
grains In weight was sfted through sieve of some
5000 holes to the inch, and again sifed through
one Of 1900 holes and the gold which passed through
was sorted under powerful lens One hundred OF
the smallest Of thess pieces then selected and
examined under microscope. Measured with
q micrometer. their dimensions in fractions
OF inch varied between 0.O09xO.OOG and
0.0O3xO 0O2. the OF twenty measurements being
0.0065xo. .0042 The hundred particles were then
carefully weighed and found to have mass of oO97
of grain-the weight OF the pieces being there
fore. o.0oo07. or little under one.thousandth of a
grain. With moderate power only, the larger pieces
were found abraded, and then but slightly; the
smaller were not water worn. and specimen was
dentritic in appearance. The finest particles
nearly equal In width and depth. and by means
iaky-coming rather under tho classification OF shoty
gold. although well defined where edges and angles
occurred.
In calculating the management of the smoke uui
sance. consumers have to deal with some chemical
factors not formerly so well known now. Tho fact
is now established that, in some Goals. there is
present notable amount OF sulphur and hydrogen
associated with their carbon. The gaseous products
of an imperfect combustion of such fuels contain
carbonic acid. carbonc oxide. sulphurous acid.
suphuric acid, the vapor of water. ammonia.
nitrogen. carbureted hydrogen. and n modicum OF
other vapors and gases of less Importance. All
of these gases md vapors escape from the cham.
bcr In which tho fuel is imperiectly burned at high
temperature. upDearing and spreading abroad the
locculent solid carbon SCOT. Most bituminous
GOALS too. when imperfectiy burned. produce smoke
of substantially the above composition. That such
smoke s Injurious to health. well to vegetation
Ia well understood; and the remedy pointed con.
sists simply In efrectiag the perfect combustion OF
the fuel used and in the of fuel whose complete
combustion Will not produce deleterious gases.
notable phenomenon, says the London Engineer.
recently o:currcd Mt the Royal Arsenal 1t that
In experimenting on firing gas in mines special gun
s employ ed TO do duty for bore hole with charge
or high explosive and pressed cylinders OF raw dry
clay three inches long and nearly that in diameter.
nrc used 10 represent tamping These shots made
to act In various mixtures OF air. coal dust and gas
and TO stop tle course Of the plug eventually cast
iron target plate inch thick, placed twenty
five feet IN front at angle of fortyye degrees. In
order 10 break up everything into dust and throw it
upward After three four shots with this arrange
ment the clay plug. weighing seven and half
ounces perforated the inch iron plate and the hole
thus made has been steadily extended since. This is
to lie appreciated In view OF the fact that the cacu.
lated velocity for hard cylinder OF this weight
size. to cut through inch OF wrought iron at an
angle or forty i've degrees would Le 500 foot
seconds.