The Salt Lake herald. [volume] (Salt Lake City [Utah]) 1870-1909, 1897-03-12
HERE AND THERE.

Mr.. Sowerby, the secretary Of the
Royal Botanic society, recently brought
before a meeting of the fellows an in
teresting collection of India rubber
producing plants. grown in the gardens
of the society. There are over a dozen
varieties of the plant from which rub
Der is obtained for commercial pur-
poses, and they possess special inter-
est in view of the enormous consump-
ton of rubber for cycle tires. The
great development of this industry is
responsible for the advance in the
price of rubber during the past few
years, and this advance might have
been still greater but for the discovery
of several species of laudophllia in
Central Africa.
Those who are interested in the pro-
duction or use of chemical maaures
will be alarmed to know that nitrate
of soda, one of the best manures, has
quite lately had a serious slur cast
upon it. The Engineer, in recording
the progress made lately in the fech-
nical applications of chemistry, says
that nitrate of soda has been found 20
contain a perchlorate, probably the
potassium salt. This was first OBJ
served by an explosive chemist, who
found the Objectionable impurity pres
ent in nitre made from nitrate of soda:
and it has been found that perchlorate
of potassium, if existing in nitrate CT
soda to the extent of one-half per cent,
is distinctly detrimental to crops to
which the nitrate has been applied. It
now lies with chemists to discover
some method of manufacturing nitrate
free from the injurious intruder.
The most expensive product in the
world is charcoal thread, which is en-
ployed for incandescent lamps Il is
for the most part manufactured at
Paris and comes from the hands IF an
artist who desires his name to -emaia
unknown in order. to better protect the
secret of manufacture 1t is by the
gram Q5A grains) that this product is
sold at wholesale. In reducing its
price to the basis of pounds it IS easily
found that the filaments for lamps
OF 20 candles are worth $4,000 per
pound, and that for lamps of 80 can
dies they are worth SO, 900 per pound.
The former have diameter of twenty
thousandths of one millimeter q MILL
meter equals 0.0394 inch), and the lat
ter four and one-half thousandths of a
millimeter. The filameDts for lamps
OF three candles are so light tislt it
would require nearly 100000 of them
TO weigh pound. AS the length of
each of them is ten centimeters e. 937
lnches), their total length would be
1S7 miles.
Experiments at the Imperial navy
yards at Wilhelmshafen have shown
conclusively that aluminium cannot be
used practically in men-of-war con-
struction. while aluminium bronze has
turned out satisfactorily in many
cases, when the alloy contained "a. 96
per cent of aluminium and ga per cent
copper. says Engineering Magazine.
After investigation and testing alumni
mum in certain parts of vessels, the
following conclusions were arrived at:
Aluminium bronze is useless for bear
lngS, valves, etc, on account of the
rapid wearing away; it has been
found useful. however, for various
parts of machines where friction is not
an important factor. and also in cases
where light weight is an object Fur
nlture made of aluminium showed de-
cldediy too little resistance and re-
quired frequent repainting; aluminium
shows, Furthermore, but little resist
ance to sea water thus making it use
less for the walls of vessels. a 10 per
cent aluminium bronze, however. 4
stands a fair chance of being freely
used as soon as the price of aluminium !
can be sufficiently reduced to approach
the value of cast steel
The idea of building iron bridges is !
hrst found, according to Ganthey. in
Italian writings of the sixteenth CEN
fury, and French engineers tried to
act upon it in the beginning of the
seventeenth. Desaguiliers planned an
iron bridge over the Thames; p Garrin !
commenced in 1719 with the construc-
ton of an iron bridge over River
Rhone at Lyons, but the difficulties
and cost of work discouraged him, and
the bridge was finally built of wood !
AT that time only chain bridges were !
known, apart from wood and stone
structures. Chains were stretched |
from one bank of a river to the other. |
and the flooring placed directly upon
them. Bridges of that kind originated
probably in China. Anastasius Kircher
escribes in 1867 a bridge in Kin-tung, |
China, which was supported by 20 iron
chains. The military bridges of the |
seventeenth and eighteenth centuries |
were of similar character. 1t was in |
where the first permanent |
iron bridge was built. 1t is the cast
iron, one-span bridge over the Severn, |
near the famous Coalbrookdale iron |
works in Shropshire. After this pat
tern many cast iron bridges were
in England during the |
last decades of the eighteenth century.
and even shipped to America. The ma /
terial for the Severn bridge was cast |
by the Coalbrookdale iron works in |
l176 to 1179, and in the latter year the !,
bridge was open for traffic. 1t is still |
in excellent preservation, and is in |
daily use for a considerable traffic |
over the River Severn.