The Providence news. (Providence [R.I.]) 1891-1906, 1897-02-20
New Type Of Engine From
Which Much is Hoped.
Some Features of the One
Invented by Darraugh.
Origin Of Iron Bridges-Chaln
Bridges First Used In China.

Providence is unquestionsbly one OF
the largest engine producing centers In
the United States and everything relating
10 improvements in that line is read with
interest not only by the owners OF ma
chloe shops but by thousands OF skliied
mechanics who make their living In
them. A recent bit Of news concerning
engines which will be found important
bv the shop owners, the mechanic and
by the general reader ss we'll, concerns an
invention completed very recently by an
Oakland, Cal, man, John Ill. Darraugh
nv name. MIR. Darraugh's inventions
during the last quarter of century have
been many and valuable, bur unfortu-
uately for him, others rather than himself
have resped the monetary rewards. The
latest product of genius and skill is how
ever fully protected by patents, so that II
its success is as complete as he confidently
expects IL will be be will yet be rich
man. This latest invention of which he
is so hopeful Is an engine that he asserts
whirls heavy trains along at the rate of a
hundred miles an hour and that too, at
q very large saving of fuel over the guam
tity now needed to draw train over half
the distance in.the same period of time.
The engine invented by Dsrraugh Is
of the rotary type. The steam Is admitted
by q rotary valve and cut off by the same
means after following the piston for any
desired part of circle. The balance of
the revolution is accomplished by the ex-
pansion of the steam. One important
feature in which this engine differs from
all others, 1t is claimed, is that there is
practically no back pressure, no dead CEN
ter to overcome and only q nominal
amount of friction. The piston is a solid
block OF iron. attached to the rim OF
steel disc which is keyed to the driving
shaft. The piston revolves In circular
cham Der, is packed with metallic packing
set cut by the steam so there is no leak
aga Of ateam past II. The back pressure 10
reduced to almost nothing, the only sur
face exposed to such pressure being the
thickness Of the steel disc mentioEvS.
point of the revolution, at one-sixth of
the circumf ference of the circle the piston
travels the balance OF the revolution on
expansion, thus utilizing the entire force
of the steam. There are two cylinders on
the same shaft, the pistons being placed
Opposite each other, SO that one or the
other 10 working on expansion.
In these days iron and steel fare about
the only materials that are used In the
construction OF bridges. All the bridges
iu Providence built within the last quar-
ter OF century are iron and when the
City Council decides to replace the pres
ent structure at Market Square the new
one will doubtless be OF iron also. lro N
bridges, however, are comparatively
modern contrivances. True. an Italian
named Gauthey suggested the employ
ment of that metal in their construction
in the sixteenth century, but the idea was
not put to q practical test until another
century had rolled around. 10 1919
Garrin began the construction OF an iron
bridge over the river Rhons at Lyons out
be become discouraged at the difficulties
encountered and tho cost of the work and
the structure was finally built Of wood.
Up to that time the only bridge, known
aside from those constructed of stone
and wood were Of the chain variety.
Chains were stretched from one bank OF
q river to the other and the flooring was
pleaced directly on them. Bridges OF
this description appear to have been first
used in China and an early traveller In
that country describes q bridge in Kin
Tung which was supported by twenty
iron chains.
Military bridges built In the seven
tsenth ana eight zenith century wer,
of this kind. 1t was in England tnst tn,
6fst permanent iron bridge was built
1t 10 the cast iron one span bridge over tn,
river Severn, near the famous Coldbrook
dale Iron WORKS in Shropshire. After thi
pattern many other cast iron bridges wer
manufactured In England during the clos
ing decades Of ths eig 1iesnth century, AM
ib several cases iron bridges made in Eng
iuuo Were snipISu ~ shis couhtIS IN
castings for the bridge over the Sever
were made at the Cold dbrookdsle Iro
Works from 1776 to 1873 and in the latte
year the bridge was orened to traffic.
10 still In excellent condition ana is 4
daily use for Q traffic Of considersbl
proportions.
"a short time ago." writes correspor
sent, 81 read sn interesting article In III
News giving a history Of the America
flag, but ! did not find in IL any explsn'
tion OF tho use Of the thirteen red an
white stripes. Can the Gossiper give tt
Much in Little