Engineering facts and figures for 1863-68

Google

This is a digital copy of a book that was preserved for generations on library shelves before it was carefully scanned by Google as part of a project

to make the world's books discoverable online.

It has survived long enough for the copyright to expire and the book to enter the public domain. A public domain book is one that was never subject

to copyright or whose legal copyright term has expired. Whether a book is in the public domain may vary country to country. Public domain books

are our gateways to the past, representing a wealth of history, culture and knowledge that's often difficult to discover.

Marks, notations and other maiginalia present in the original volume will appear in this file - a reminder of this book's long journey from the

publisher to a library and finally to you.

Usage guidelines

Google is proud to partner with libraries to digitize public domain materials and make them widely accessible. Public domain books belong to the
public and we are merely their custodians. Nevertheless, this work is expensive, so in order to keep providing tliis resource, we liave taken steps to
prevent abuse by commercial parties, including placing technical restrictions on automated querying.
We also ask that you:

+ Make non-commercial use of the files We designed Google Book Search for use by individuals, and we request that you use these files for
personal, non-commercial purposes.

+ Refrain fivm automated querying Do not send automated queries of any sort to Google's system: If you are conducting research on machine
translation, optical character recognition or other areas where access to a large amount of text is helpful, please contact us. We encourage the
use of public domain materials for these purposes and may be able to help.

+ Maintain attributionTht GoogXt "watermark" you see on each file is essential for in forming people about this project and helping them find
additional materials through Google Book Search. Please do not remove it.

+ Keep it legal Whatever your use, remember that you are responsible for ensuring that what you are doing is legal. Do not assume that just
because we believe a book is in the public domain for users in the United States, that the work is also in the public domain for users in other
countries. Whether a book is still in copyright varies from country to country, and we can't offer guidance on whether any specific use of
any specific book is allowed. Please do not assume that a book's appearance in Google Book Search means it can be used in any manner
anywhere in the world. Copyright infringement liabili^ can be quite severe.

About Google Book Search

Google's mission is to organize the world's information and to make it universally accessible and useful. Google Book Search helps readers
discover the world's books while helping authors and publishers reach new audiences. You can search through the full text of this book on the web

at |http: //books .google .com/I

ENGINEERING FACTS AND- FIGURES

FOR 1863.

&.\'

ANNUAL REGISTER OF PROGRESS IN MECHANICAL
ENGINEERING AND CONSTRUCTION.

EDITED BY

ANDREW BETTS BROWN,

MKOHANIOAL ENQINEKR.

SECOND EDITION'.

LONDON AND EDINBURGH:
A . F U I. L A R T O N Sz CO

1864.

■ I'-

I : ; ■- :

\ .

"»'>[/

61 794 A

. rDIXBLHGIl:
• I^I.LAKTON AND MArNAB. FKISTKRS, I.P.ITII WALIT

P R F, F A (' K .

ilmpossible to ovei-estiuiate tlie iiii|
^d science of Engineering as one of tlie jKiwers whicli
iiiistei's to the material wealth aiid prosperity of this
ntry. Its followers, by their mechanical ^nius, and by
r patient and painstaking industry, have clmnjreil the
f face of tlie material world, Tlieir woiidmus working
ichflitisin has almost snniiiikted time and spacu, — hna bid
liiance to the winds and waves, — lias clotlied a world,
I in a tliousand ways ministers at once to the cuintbns
I tbe luxaries of our people. Eiipineering is pi'e-emi-
[Htly a propressive science, and tbe exjwi'ieiice of to-diiy
t belps to improve and extei.d the labour of to-morrow.
Notbing, therefore, could be more interesting tbnn to trace
tbe bistory of the science in all its departments, and t<> take
note of the feeble way in wbicb, in their earlier times. En-
gineers step|ied forwaitl in tbe path of progress, contrasting
it witb tbeir assured mien and finn step in maturer man-
But unfortunately tbia history of the ait does not
ist, and witli it the lessons whicli Engineers of tbe ]>re8ent
might have learne<l ti-om that which Ims long passed

■ them, are irretrievably lost. It is dlffiewU l« sa^'

■ &i" saff^estire these lessons ■W(ju\i\ \\ftv*i \>ccw

t all events, with safety be predicteu' 1
lulil have been to a very large extent useful. Tii
rnerience of those who have gone befoi-e ns in a (lath
F difficulty which their energy and industrj' have made
niparatively easy is invariably valuable: and if its re-
rds do not always point out the course to be followed,
tliey are not the less useful if they give warning of the
ihnifrers which are to he avoided. The pilot who warns the
sailor of the rock performs as good a service as he who shows
|[tliB safe entrance to the harbour. A complete recoixl theH
f past experience and practice would have been of immense
Mmpoi'tance to the Enj-ineertng world; and it cannot but be
matter of repi-et to those interested in its sound progress,
||jiat that recui-d dues not exist. Regrets, however, are use-
s where regrets are vain, unless, indeed, they
make np the failings of the past by provision for tiie futil
Uming in this direction — a direction of undoubted utilit*
—the pi-esent work has been projected. There is fortun-
ately now no lack of materials existing amongst us with
which to fill its pages; they are abundant exceedingly — and
C0ut of them we can extract, if we will, matter of immense
ractical value. But scattered here and there, many of
a are out of tiie reach of numbers of practifal men ; and
s to bring tliem within their reach that is the object of
far work.

It is not designed to embody the ophiions of the Edi-
tor; what is wanted, he believes, are opinions of thdse who,
either by their theoretical investigations or by tlieir practi-
^^ral works, are enriching the art and practice of Engineering,
^Hnd aiding the progress of those works which, whether in
^H^ exqninite accuracy of minute mechanism, or the \k>\v>

PBKFACE-

:l irraiid stabilitj' uf more imposing ituKrliims and 1

i, are making — as they hart alrmdy maJe — lli« Eii-

Eneerin^ interest of Great Britiiin one nf llie most remark-

ble features of the a^ we live in. At the same time tin-

iditor has ilt-eraetl it not out of place to giv here and thwe

marks of Iiis ovn bearing on the sulijects which may hv

under discussion. For tliese he is, therefore, responsible,

and he can only claim fbr them the merit of being derived

from practical experience.

In a work treating of no many departments of a many-
sided art, a good arrangement of its subjects is obviously of
the utmost importance. It is not enough that the Editor
i to his Readers a mass of matter, it is essential also
iat tliis matter shall be presented to thent in such a way
t to any part of it to which reference is desii-ed, reference
y be made with the greatest facility. The good arrange-
int then of the work has been a matter of the most anxi-
e on the part of tlie Editor, and he believes that he
lucceeded in some degree in securing it.
B bave said that the materials for such a work abniind.
y exist in the nanieroua periodicals and reviews, de-
ted, some exclusively, some partially, to the discussion of
bgineering subjects, and in t!ie Transactions of Engineer-
[j and Scientific Societies; and the vast mass of matter
leininated in this country, is supplemented and rendered
il more bulky by the corresponding materials of Foreign
intries, of the North American States, ami our own

! Editor is aware tliat there are other publications
iching on the same ground, but while gladly acknowledg-
; their usetvhiesa and the ability wit\i wh\i;\v t\\e'j we

PREFACE.

^feonducteil, he believes th»t they do not occupy the same
^Vpositioii as that which it is the pui'pose of his own to take
^Ftiji. Much of their space is taken up by the introduction of
matter whicli, however interesting to some classes of
scientific men, is not so to Engineers. To Engineers
atone the present work is dedicated, and for them alone its
pages are designed. The utmost care shall be taken to
make its pages a careful record of the facts of the year;
the Editor, therefore, shall be gratified by such suggestions
as may be calculated to make it tlioroughly complete in all
its departments.

In presenting this, the first volume, the Editor has to ac-
knowledge his special obligations to the following Journals
published in this country, all of which are conducted with
admirable ability, and contain a vast variety of valuable facts
md papera. He can only regret that the limited space at
B disposal has prevented liim from drawing the attention
F Ilia readers to other subjects discussed in their pages:
—The Engineer; the Mechanics' Magazine; the Practical
Itechanics' Journal; the Engineer and Ai'chitect's Jotimal;
the Building News ; the Builder ; the Chemical News ; tlie
Scientific American, published at New York; and the
Transactions and Reports of '^'e Scientific Societies and
■ Associations.

CONTENTS.

DIVISION FIRST.

Boilers, dbc, —
Riveting) .......

Brass and Iron Tubes, .....

Marine Boilers, ......

Locomotive Boilers, .....

Manchester Steam Boiler Association. Engineer's Reports,
BUstered Plates, ......

Safety-valves, ......

Mode of Setting Boilei-s, .....

Steam and Water gauges, .....

Explosion Theories — D. K. Clark's Projectile Theory,
Steel Boilers, ......

3
7
15
17
17
21
23
55
61
67
73

DIVISION SECOND.

Stationary Steam. EngineSy —

Piston Speeds of Beam Engines, . . . 77
Investigation into the Causes of Fracture in tlie Hartley Colliery Pit

Engine Beam, ...... 79

Horizontal Compound Engines. . . . . . 102

Piston Speed of Steam Engines, . . . 107

Power of Steam Engines, . . . . . 112

High and Low Pressure Engineu, , . . . . 115

DIVISION THIRD.

Locomotive, Traction, and Marine Engines, —
Weight and Speed of Locomotives,
Siaa/f and Lai^e Wheeled Locomotives, .

via

CONTENTS.

Pajre

Light Locomotives, . . . . . . 127

Smoke Consumption of Locomotives, . . . . 129

Internal Disturbing forces, . . . . . 132

Balancing of Locomotives, . . . . . 137

Valves and Link Motion, . . . . . 140

Wheels and Tyres — Adam's Spring-seated Tyre, . . 144

Mineral Locomotives for Colliery Lines, . . . 146

Gauge, ........ 154

Locomotive Expenses, . . . . . . 156

Comparative Expenses — America and England, . . 158

Midland Railway Expenses, . . . . 159

Traction Engines, . . . . . 160

Wheels and Tyres, . . . . . 164

Requirements of the Road Locomotive Act, . . . 165

Aveling's Traction Engine, . . . . . 168

Trials of Engines at Worcester Royal Agricultural SIiow, . 173

Tabulated Result of Trials with Prizes awarded, . . 174

Messrs. Randolph and Elder's patent Marine Engines, . . 176

Messrs. Humphrey and Tennant's patent Compound P^ngines, 177

Superheating Steam, . . . . . 178

Surface Condensation, . . . . . 181

Comparison with Locomotives, . . , . 182

Brasses and Bearing, . . . . 1 86

Heating of Journals and Means of Curing, . . 189

Anti-Friction Material for Journals as a Substitute for ]VI(.4al, . 190

Engine Construction, . . . . . . 191

Different Descriptions of Metallic and Steam-packed Pistons — their

Relative Efficiency, . . . . . . 197

DIVISION FOURTH.

Steam Fire Engines, —
Description and Dimensions of Messrs. Shand and Mason's Steam

Fire Engine, ....... 209

Messrs. Shand and Mason's Small Engine, . . . 210

Messrs. Merryweather's Steam Fire Engine "Sutherland," . 211

" ** ** "Torrent," . 212

Messrs. Easton and Amos* Steam Fire Engine " Sabrina," . 212

3Ir. Boberts' Steam Fire Engine, . , , . 1\Z

CONTENTS.

IX

Messrs. Bntt and Co.'s Engine " Victoria,"
Messrs. Lee and Co.'s Engine "Alexandra,"

** "Manhattan,"

Messrs. Grey and Sons' Engine, .
Trials at Crystal Palace, Sydenham — Tabulated Results,
Boiler of Steam Fire Engines,
Working Expenses of Steam Fire Engines in America,

Pn:re
214
215
21 r>
215
21 «
228
225

DIVISION FIFFH.

Turbines, —

Description of Turbines, ..... 228

Foumeyron and Journal Wheels, .... 229

Construction of Turbiues, ..... 2H0

Formulae used in the Designing of Turbiues, * . . . 2:J2
Voilex and Whirlj>ool Turbines of Messrs. Williamson, Brothei-s,

Kendal, ....... 235

Working of Turbines, ... . . . . 241

^Superiority of the Journal or Parallel flow Turbine, . . 243

DIVISION SIXTH.

Rail ways, —

Underground Railways, . . . . . . 244

Hawthorn's System of Working Railways, especially those Under

Ground, ....... 245

Lighting of Railway Carriages with Gas, . 249

*• Bhore Gaut " Incline in India, .... 251

Character of Engines Required to Work Incline, . 266

Effects of Railway Curves on Rolling Stock, . . 257

DIVISION SEVENTH.

Iron,

State of Carbon in Combination with Iron,

Grey and White Irons, .....

Influence of the Hot Blast— the Quality and Produce of Iron,

Extraction of Iron from " Cinder,"

Test of Quality of Melted Irou, ....

Manufacture of Wrought IroD, ....

263
265
267
273

CONTENTS.

Puddling,

Manufacture of Steel,

Krupp's Steel,

Riepe's Process of Puddling Steel,

Bessemer Process,

Mayer's Cast .Steel,

Cast Steel Bells,

Cast Steel Locomotive Wheels and Tyres,

Steel Castings,

Sudre's Method and Furnace,

Application of Sudre's Steel,

M. Caron's Investigations into the Chemical Constitution of Steel,

Extended Use of Steel in the Construction of Machinery, &c. ,

Factor of Safety in Structures, ....

Relations between the Safe Load and Ultimate Strength of Iron,

Elasticity of Iron, .....

Permanent Set of Cast Iron Girders imder Pressure,

Breaking Strains of different Descriptions of Wrought Iron,

Calculation of Strains on Iron, ....

Elastic Limit of Iron, .....

Strength of Iron under Continued Strain,

Safe Load of Iron, .....

Testing Iron Railway Bridges in Prussia — ^formulae,

Mr. Kirkaldy's Experiments on Iron and Steel, .

Comparison of Fractured Area with Original Area of Specimens,

Influence of Frost on Iron, ....

Breaking Strain and Fractured Area of Iron, . . •

Paire
276

280

284

285

285-293

289

290

291

293

295

303

304

312

313

314

317

321

323

329

331

333

335

336

337

343

347

349

DIVISION EIGHTH.

Timber y —

Properties of Timber,

351

Growth, .

• ^ •

353

Sapwood,

• • •

355

Density, .

• ■ •

359

Weight, .

• • •

3(;i

Elasticity,

• • • •

363

Jiroakinty ''''

" *• — formulse,

■ • •

365

Pei'iof

9S,

• • •

^vi-v

CONTENTS.

Diseases of Trees,
Preservation of Timber,
Seasoning of Timber,

Pair*
869

871

879

DIVISION NINTH.

General Machinery — tndvding AgricuZtural Implements, —

Wood-working Machinery, ..... 881

Wheel-cutting Machines, . ' .

885

Cutters, . . .

887

Tooth-shaping Machine,

889

Coal-mining Machine, ....

391

Boot-making Machine, ....

893

Type-setting Machines, ....

895

Steam Ploughs, .....

897

M*Rae*s Plough, ....

403

Hayfts' Plough, .....

405

Howard's Plough, ....

406

Fowler's Plough, ....

407

Coleman's Plough, ....

407

Trials of Different Ploughs,

408

Seaman's Plough, ....

409

Award of Prizes, ....

409

Garrett and Son's Traction Engine,

411

Clayton and Shuttleworth's Traction Engine,

412

Fowler's Ploughing Engine,

413

Howard's Steam Cultivating Apparatus,

413

Collinson Hall's Plough,

415

Practical Hints in the Manufacture of Machinery,

416

Economic Advantages of System,

417

Are Scraped Surfaces Indispensable ?

418

Keying Wheels on Shafts,

419

Piece-Work, .....

421

Construction and Repair,

422

Abuse of Files, .....

424

ENGINEERING
FACTS AND FIGURES FOR 18

DIVISION FIRST,

[ BOILBRS iND VESSELS FOR CONTAIN I NO STEAM AND UTHEK
HIGHLY-PEESSBD ELASTIC FLUIDS.

[ this section of mechauicol engineering no decided novelty or
mprovement Las been introduced during the past year.
p manufacture of boilers and other iron atructurea is ho much
(plified that, comparatively speaking, little advance lias been
~ 1 the forma of and the details of manufacture. The
lating," " riveting," and " caulking,'' may be said to make up
of boOer- making. Of course in other boUera, according
Idesign, tubes and other small passages for fire or water are
e use o^ and consequently involve a different class of work-
jDship in producing euch tcbes, and in efl'eotively fitting them
I their place in the boiler. Of plating little has transpired
; the paat year worthy of special notice. Of riveting,
wever, some improvements have been introduced of late years,
Ti as in machine riveting, hot and cold riveting, &c. On this
nJBct W. H. Eing, of the United States navy, in hia "Practi-
■ notes on Steam," says of riveting : — " In the United States
) three mechanical modes of uniting plates together;
hoely, maeAine-riveling, and hot and cold liand-riveting. On
V seaboard all kinds of boilers arc riveted by the two first-
pied methods, in both of which the rivets are put in hot.
t of the Alleghanies, all riveting is done by hand ; and at

ENGINEERING FACTS.

^^B Fittsbuigb, Louisville, and other places, the rivets are driven

^B ooid in all places aceesaible for the purpose.

^H " For tbe cold proceaa a superiority is claimed consequent upon

^r the holes being well filled with the body of the rivets ; that is, there
can be no contraction — hence reduction in the strength and in
the rivets' diameters after the Workmen cease hammering on the
heads, The reverse must be the case when driven hot ; for, in
cooling, the diameters are reduced hy contraction. Moreover,
none but the hest quality of iron can be used in rivets driven
cold ; becanse, if the iron he inferior, it is sure to crack or split
through the head, each one being tested by the heading.

" For hot riveting it is claimed that, in cooling, the rivets con-
tract in length, drawing the aheeta more closely together, thereby
creating adhesion sufficient to add to the strength of the joint.
Mr. Clarke, resident engiueer of the Britannia-hridge, made some
experiments to determine the value of this. Thi'ce plates were
riveted together hy a machine, maintaining a temperature of 900
deg. in the rivets ; each ontside plate had a circular hole in which

»the rivets fitted exactly ; but in the centre one the hole was oval,
or 2^ in. long for a § rivet, and the rivet Was not allowed to
touch either end of this hole. A strain was then put on the
centre plate till it hegan to slide, which it did abruptly. Several
trials were made, and the least result was an adhesion equal to
4j tons with § rivets, Mr. Clarke infers from this experiment
that, by judicious riveting, the adhesion may in many cases be

I nearly sufficient to counterbalance the weakening of the plates
from punching the holes. Tn this particular we regard his opinion
as an error; for if he had continued the strain on the plate until
it parted, or the rivets broke, he would doubtless have found
that the total pressure, or breaking strain, would have been S6
per cent, if single-riveted, and 75 per cent, if double- riveted, of
the sheet, as fuUy tested by other experiments. Theoretically,
there is a gain from adhesion in hot-riveted joints, but practically
this seems to be lost by the contraction of the rivets' diameter,
thus making the total or breaking pressure the same.
*' In western river boilers, where the pressure of atearo nsed is
higher than in any part of the world, no difficulty has ever been
experienced from the cold-riveted joints not being closely united
»tiel perfectly tight; and as regards slteT^i^'Vi coTO^a-red -with the

■s-l EITETIKC.

it-riveted, superiority is claimed bj tliuae Imiiug cold-rivetL-ii
boilers in charge.

" In either mode of htind-rivetiDg tlie livetd crni be «^riouslj
injnred by too much haumieriiig, and iu any case by overlieating.
Dae regard should be had to the temperature, and the blows of
the hammer ehould be hard and quick, and not continued longer
than necessBiy to farm the hecuL Machine riveting has the ad-
yantage of forming the head at a eiugle blow, and the rapidity
ith which the work can be pei^ormed moat always give it pre-
ver all other methods where it can be employed,
to be regretted that no extended set of experiments have
1 made in this country to determine the relative strengths
of tbe difierent modes of riveting and uniting the sheets of steam-
boilers and other iron stmctures; aJao to test the relative value
of the materials used in this country at the present day ; fur it
mu^ be evident that although the restilta of European experi-
menters on iron and steel are of value to ua, yet they cannot be
regarded as entirely applicable to American constructions, because
oar iron ores, the temperature of blast of smelting furnaces, and
jttftnner of working the metal through the different processes,
nd the fafsl used, all difier in a large degree from those abroad."
b According to this authority it seems that cold riveting is much
^Bctised iu America. We should think, however, that it would
H very much more expensive, and, at the same time, unless tbe
Hn vas unusually good and well annealed, the head would be
Bble to split at the edges before being properly finished; proba-
Bt matthiiie riveting would give the best results cold. Several
Hempts have been made to unite boiler [dates by welding, and
Hmongh the practice biis not become general, yeb considerable
Beceea baa attended such operations, and it yet remains for en-
B^rise and capital to bring such a systeu) to a practical issue.
Bie Mechanics' Magazine says on this subject: — "The employ^
■nil of rivets for securing metal sheets or plates together, is of
Hctremely ancient date. The principle must have been obvious
■ the firet workers in iron, and being really susceptible of very
■tie improvement, the art, if such it can be termed, has been
fcnded down from generation to generation without alteration,
■hnost the only difference between the boiler seam of a century
Bo, and that of the present day, ia found in the use of thti

ENGINEEEINO FACTS. [Div

^H 'snap, for finishing the rivet point. We are not aware of the

^H existence of any very old etmcturea of plat« iron which have the

^H rivets so finished. 'Snapping' a rivet only aiida to the finish

^V oi a joint, hut in no way conduces to its strength, and can

^ Bcaroaly be cunaidered in the light of a substantial improvement

" Until a comparatively recent date, the belief obtained with

most engineers that a riveted joint, if the work were properly

executed, was superior in strength to the plal« itself — an assumed

fact which they endeavoured to account for, on the ground that

the contraction of the rivet during the process of cooling, bound

the two surfaces in contact so closely together, that the friction

t between them prevented the exertion of much shearing force on
the rivets, and compensated for the weakening occasioned \
punching the necessary holes near the edges of the plates. The
&llacy of these arguments was often demonstrated by the failnre
of riveted joints while the plates remained intact. Keverthelesa,
the advocates of the theory held out strongly in support of these
views, until Mr. Fairhaim conducted a very valuable series of
experiments, which resulted in proving, that the strength of the
plate being taken as 100, that of a double- riveted joint will be
70, and that of a single-riveted joint 66. This, be it remem-
bered, with first-rate workmanship. American engineers have
tested the real value to be attached to the fiiction between two
auriacas riveted together as in ordinary seams, with the exception
that the holea were made oya! in the direction of the strain for
the purpose of experiment. A very considerable force was re-
quired to cause the plates to slip on each other, but this.fact did
not affect the results in the least. They amply confirmed those
given by Mr. Fairbairn. fi.6 per cent, of the whole strength of
tlie plates which form a steam-boiler is certainly not much to
realize with the best workmanship; but as many of our boilers
and ships are put together, even this per-centage must b
garded as too high. There are difficulties involved by the na-
ture of the process which the best mechanic can only combat,
seldom or never overcome. However accurately two plates may
correspond before the holes are punched, that process inevitably
distorts them, and occasions a bad fit when subsequently put
together. Tlie hammering and bending at the edges entailed, ia
in\-armb}y injurious to cold plates. &.ga\n, t\\e Wat VQasibie

irknien, with tLe best machinery, find it out of the que^tipn to
make all the holes in a. long seam correspond. The coustant ute
of the drift is a result certain to fullow; and when plates are (if
inferior quthty or very thin, and the holes near tlie edge, cracks
are frequently estahlished from one to the other, The judicious
uae of the caiilkiug chisel easily conceals the defect, which is
nnne the lees serious because it is invisible. Even the drift
often faOs, however, to secure the entrance of the proper rivet,
and one made of lead ia the sabstitute. The best rivets, too,
seldom completely fill the holes they occupy. They are seldom
'If never truly at right angles to the plates, and are often exposed
til an enormous strain in drawinj; plates together where they ire
badly fitted. We have seen from this cause the heads fly off
bnlf a. score of ' Best Beat' rivets at once in roiling a new boiler
from one side of a shed to the other. Wlien we take all these
i^ircumstancee into consideration, we believe that 46 per cent, of
the strength of the plates will pretty accurately represent that of
the seams of a very large proportion of our boilers if single-
riveted, OS most of them are.

" Impressed with the evils of such a system, Mr. Fuirbaim in-
troduced the use of iron plates rolled with thickened edges, to
compensate for the loss of strength entailed by the holes. The
nlijection to their employment he sums up in a few words :^-
' At the commencement of tlie trade in iron ship-buiUing I
patented an arrangement for rolling plates with thick edges, and
i.'iaployed plates so prepared to some extent; but the cost of
jiroductiou at that time and some difBcultiea in their employ-
ment prevented their general use.' The whole principle, indeed,
I if riveting boilers ia so erroneous that it is scarcely susceptible
■ if mucli improvement.

"Within the last few years attempts have been made, with mure
oi' less success, to unite the plates of boilers, ships, &c., by weld-
m-„', instead of riveting. The first English patent, apparently,
which touches on the subject, was taken out in 18&B, by a Hr-
WhitehoQse, for welding tubes 'by circumferential pressure
without a mandril' The next was by Stratton in ISil, fo\
■vfilding plates to form hollow ribs for sliipa ; v(bic\i l\ie ^a\ftu\»fc
.■■r,>pos3ii to effect, by Tolling stripa of metal concave, vj\\,\i &?»%«* ■,
Juak,^i^ of metal being placed with theii coiwava sniKft^si

I
I

I

t ENGINEERING FACTS. [Div. I,

wards each other, and the flanges being welded together, formed
tuhulat riha for ships, &c., as proposed Some of the first loco-
motives btiilt by Bury had welded joints. A patent was ob-
tained by William Bertram in 1854, which seems to be the liret
proposing the application of a gas flame urged by a blast, to the
heating of plates to be weliled. The patentee acarfed the edges
of the plates, placed them together, and directed two pure gas
flames, obtained by the combustion of coal or coke in suitable
furnaces, on either side of them until raised to a welding heat,
when they might be united by pressure or hammering. William
Mni^n patented nearly the same process in January 18fi6.
Enasell, in 1859, proposed to employ a framing with two arms;
the lower one supporting a convex tool or anvit, wliich going
inside of, aided in sustaining the boiler being welded, its weight
chiefly resting on rollers, which were fixed near the ground
Tlie upper arm carried another tool or hammer with a convex
face, which was traversed up and down in vertical slides, on
much the same principle as that involved in Rider's forging
machine. Two portable gaa furnaces wore provided, one within,
the other outside the boiler, to raise the plates to the welding
point. The whole apparatus appears to have been simple and
well-contrived; but from some cause it has not come into general
use. Alleyue, in December 1859, patented an invention for
welding boUer plates, by the intervention of a 'glut,' which
consisted of a bar of iron, with a cross section resembling L
The edges of the plates to be welded were inserted into the
grooves, which aided in retaining tiiem in their place. The
whole was then exposed to suitable gas jets, and raised to a
weliiing heat and united by the pressure of rollers or by the
hammer. The 'glut' was intended to prevent the oxidation of
the plates; a needless precaution, as flame is incapable of oxidat-
ing a metal surface. Still there are certain matters of practical
convenience, which incline ns to the belief that the principle in-
volved in this patent may be occasionally employed with advan-
tage, particularly in welding transverse seams in circular boiler

The subject of tubes is one of considerable importance, and
fonuB H very seritms item in tlie expi'TiAitute <ii ftie Incomotive
jfepaHment of raUwaya. Brass tu\wa \ia\e \u.ftvfetta "

BRASS AND IRON TUBES. 7

fely used, most railways oonaidering them is thti end
} economical Ihoit iron ones, from tLe fact of their being
)nerally able to "piece" sucli tubes by brazing, and thus put
'n a second time, at the same time tbe mettJ being, when
done, valuable for braSBCs, &o. Iron tubes, of course, when once
taken out, are useless, and, as old metal, comparatively wortlileas.
On this subject the Mechanics' Magazine says; — "It is well
known that brass boiler tubes are genemlly adopted in England
in preference to those of irun; nevertheless, some railway com-
panies ase iion tubes to a great extent A difference of opinion
still exists as to tlie comparative advantages of the two kinds; a
series of esperiments and a record of actual results are the only
means to get at the troth of such matters. For some time the
Fmssian government railways have been uaing wrongbt-iron
boiler tubes for their locomotive engines. Eusults extending
over several years allow us to believe that this kind of tubing is
at leaat equal in strength and duration to brasa tubes; while for
locomotives, iron tubes are superior in economy with regard to
first cost, repairs, and renewal It is generally found that they
are lecis subject to split in the direction of their axes, and thus
cause leakages, than brass tubes. No case has yet occurred of
the explosion of one of these pipes; an accident which ia not
unfpcqnent with brass tubes. Wrought-iron tubing can also be
Jixed without the inside ferrules that always somewhat diminish
tlie useful beating surfaca Being of the same metal as most of
the other parts of the boiler, they are subject to a similar amount
of expansion and contraction by beat, and the different parts are
thoa better united together. The objections that have been
raised against wrougbt-iron tubes consist in their favouring the
increase of incrustation ia the boiler, in being fined with greater
difficulty to tbe tube plates, and in forming leaky joints. With
regard to the last objection, that of liability to leakages at the
joints, it may be stated that this fault does not seem to be in^
herent to iron tubes; at least when the fire-box and smoke-box
tube-plates are new, the holes are exactly drilled, and tbe caulk-
ing is properly done. "Wrougbt-iron tubes, when first intro-
duced, were naturally employed to replace those of copper or
brass, and thus the holes ia which they were to be fixed lost
their circular shape and regularity in consequence oi le^am wA

r

I
I

ENGINEERING PACTS. [Drv. I.

p^vious woTkicg. Copper aod brass tubes, possessing more
malleability, suited themselves to any irregularities, and could
form tight joints, being in this respect superior to iron tubing.
Generally BpeafciTig, it 13 to be remarlied that iron tubes often
require to be replaced when the fire-box and smoke-box tube-
plates are in a bad states the most frequent cause being leakages
at the joints ; and when iron tubes once become leaky, their
ends get soon wasted away, and cannot afterwards be depended
upon. The ZeitscJirifi fwr Sauwesen gives the following com-
parative results as to the use of this description of tubing. Ttie
engine No. 23, on the Aix-la-Chapelle to Duseeldorf line, was
fitted with iron tubes since the year 1857 ; and, up to the latter
end of the year 18S1, the engine had run 78,747 kilometres
without any accident to her tubes. On several other Gbnnau
lines iron tubes have been used almost exclusively since 1867-8.
"Iron tubing has been used on the Wostphalian net of lines
since 1857. During that year six engines were made with iron
tabes; and in order to institute an exact comparison as to the
relative fldvantagea of the two kinds of tubing ; a few montha
later, six other engines were made with copper tubes. By the
month of October 1861, 214 of the 978 tubes (21-9 per cent)
contained in the first six engines had been changed. The tnbea
had been on an average 28 months in use, and had riin 69,600
kilometres. The six locomotives, taken together, had travelled
in all 295,380 kilometres, but one of the six had travelled
98,000 kilometres, which accounts for the average run of the
tubing being nearly 70,000 kilometres, while the average dis-
tance run by the engines experimented with is only 50,000
kilometres. It may be taken for granted that the last engine .
conld have run a further distance of 50,000 kilometres without
using up her tabes.

"In the six engines built with copper tubing there were 937
tubes; by the end of the year, 1861, 348 of these tubes had to
be changed, (or 37 per cent.) after an aven^ duration equal to
23 montha, and an average run of 48,480 kilometres, The
total mileage of the locomotives with copper tubing amounts to
344,415 kilometres, while that of the engine the most used
'aa}s 103,670 kilometres; and it was then calculated that the
troalii Jaat for « further i^tance oi &(^,WU Y\\ikiaui^inA,'

^f)

HEAT-CONDUCTIKO POWEE OF TDBES,

the iron tubes, instead of having nnly ran S95,O00 kiloinelres,

had run 345,000 kilometres, like the brasa tubes, the proportion
of 21 '9 per cent, of their renewsl would have been raised

tcJ'iliLiy = 25-6;
29fi
to say, 35'6 per ctint. of the iion tubing would hav« to
Teplaced. This must be compared nith the average of 37 I
cent, given by the brass tubing. The Prussian line on
which iron tubes are the most extensively employed, is the Nie-
derschlesisch Morkisch Eailway ; 30 locomotives are used for
the traffic on that line, and are furnished with a total number
of 4,503 iron tubes. Only TSl [leroent, of these tubes required

"According to Despretz, the conducting powers of iron and
copper are respectively as the numbers 37* and 898, gold being
taken at 1,000. These powers, however, are subject to great
variation under the influence of practical conditions. Tlie num-
bere cited above have been obtained when the Burfocea of the
metals were dean and bright^ and w«re not sutject to those prac-
tical influences thiit often completely modify the expectations
formed by calcalation. In the year 1857, Mr. Tosh, of Mary-
port, read before the Institution of Mechttnical Engineers n
short account of some esperiments he had carried out in order
to ascertain the relative conducting powers of brass and iron
tubee. He used two vertical hoUers of equal dimensions, 6 in.
diameter and 2 ft. long, with a single tube in the middle of each,
2 in. external diamel«r and No. 1 4 wire gauze thickness, of brass
and iron respectively. 'The two boilers were filled with water
of the same quality and of the same temperature, and alternately
placed upon a stand in the same position over a gas flame; they
were each exposed to the action of the gas for the same lengtli
of time, which was equivalent to the same quantity of fuel being
consumed in each case; and the height of water was carefully
ganged after each experiment as soon as ebullition had ceased.'
tireat care was taken to prevent any change in the pressure of
the gas. According to Mr. Tosh's experiments, the evaporating
power of brass is to that of iron as 125 to 100; or brass will
evaporate about 26 per cent, morewatei' tban won, '♦!\'i.V ftvft
" r of/ael £sperimeiit8 were also mede mfti \rtQs»

I

in ENGINEERING FACTS. [Di>

and copper tubes, and copper waa faund to be as auperior I
liRi^ aa brass to iron. The relative evaporating powers of c
per and iron were found to be as 156 to 100, and, according t
tliis result, copper sbould evaporate 96 per cent, more wat«t tJia
iron, using an equal amount of fuel In the discussion that ea
sued, 'Mr. Tosh said that the consumption of gas bad not bet
regulated by a nister, but a uniform pressure had been attaiiu
by applying to the authorities of the gas works.

"Pmfeasor Haukiue said that a number of exporimenta ht
beeu tried many years ago with experimental boilers of iron ax
copper of different thicknesses. These experiments were tri(
by Mr. James E. Napier, and he heated the boilers over the san
gas fliinie, but found only a slight difference in evaporatin
power of about l-20th or l-30th to the advantage of the coppa
Professor Bankine stated that in all oxperimenta of the kind t'
state of the heating surface waa an important matteri aa to wt
•-.her it was smooth or rough, either perfectly clean or encmet^
to any great extent. The effective evaporating result, or t
iilission of heat through metal, as waa also stated by Mr, .
kine, evidently depends on three properties: — *lst, the n
ance of the first surfiice to absorption of heat from the heata
aie and gases; 2d, the resistance of the internal particles of t
metal to the conduction of heat; and 3d, the resistance of t
second surface to giving off heat to the water: those thre
[iropeities were not possessed in the same proportion bydifferen
bodies ; the resistance to internal conduction was less in coppe
than in iron, but the resistance of the surface v
per.' Mr. £ankine recalled to the minds of the menibiiB of th
Institution the well-known experiments on the transmission (
heat, made by Mons. Pecleti who found that metals all conducted
pretty much the same when their surfaces wei-e dull It ia e
dent that, in the experiments we have cited, the tubing v
scarcely nnder the same practical conditions as in a locomotivfl
boiler. Mr. Siemens alluded to another difference, owing to au^
viiriation of the draught on the gas flame through either of t'
tubes carrying off the heat with greater speed; 'the brass tube
might also gain an advantage from their smoother surface causin|
Ifss adhesion of the minute bubbles of steam during slow ebnlU
iiaa, tlioagi that circumstance would iuA vi^'^'j v

f

tion,' It would tlius appenr that iron tnbes are practically eqnnl
iTi heat-transmitting powers to brass tubes. As reganl* dunition,
tliey actually appear to bo superior tn braaa tnbes, especially
when any leakages are avoided by careful attention and work-
Titflnship,"

In the manufBctnre of tabes great iinpiovement has been
niade, the solid drawing of brass tubes being an important ona
lii>n tnbea, however, are atill made by lap weMiiig, and there-
not the solidity of brass tubes. Several patents have of
been taken ont in oonnection with solid cold-drawn tubes,
barret^ &c., and frcira experiinentB made, seem to promiee
_ production of wrought iron boiler tubes, cold and solid
drawn, and of greatly increased strength, so that the same thick-
ness will not be required. On this aubjeet the Mining Journal
gives the following description of a company forming for the
of introdnoing such tubes:
'The many purposes to which cheap and reliable iron and
~ tubes could be applied are so well known that it is quite
refer to them — boiler-tubes, hollow axles, hy-
mUe pipe^ holinw taps, jsurface coudenserp, piston-rods, steel
and gaa piping, being but a few of the articles for which
»y could be substituted for those now employed. Such being
case, it ia concluded that an invention that admits of tubes
of almost any length and diameter being drawn from the cold
metal, and of a quality capable of being used even for gun bar-
rels, could not fail to prove remunerative to those developing it ;
impany has, therefore, been incorporated under the Companies
with limited liability — the Solid-drawn Iron and
il Tube Company — with a capital of £160,000, in shares of
eacli, for purchasing anil developing certain patents for the
lu&chire of iron and steel tubes without join or weld, in a
>id and most economical manner, and of any shape, size, and
Ch within the ordinary limits of mechanical force.
The advantages claimed for the invention are really marvel-
Tlie tubes being drawn cold, and without any action of
an enormous saving results in the metal ; thus, by this pro-
two Enfield rifle barrels of the standard size, weight, and
igtli, can be drawn fiviu the piece of metal now commvwA \ft.
minuSuiture ofojie fcarrej, while the process ia ao mttS-Yew

ENGINEEEING FACTS. [Div. 1.

aive that an Enfield rifle barrel of the present kind can be pro
duced for less thaa oiie-biilf the present cost, and a Bt«el barae
of like length and dimensions for the present price of iroi
The proofs to which the new coldnirawn steel gun '
and tubes have been submitted establish, heyoud doubt, the £
tliat the metal employed is of excellent quality, and that tfai
mode of manufacture is thoroughly applicable to all the parpoaet
to which it has been applied. The privileges to be purchaseii
by the company include not only the processes for manuiacttii!
ing the tubes, but the mongpoly of the peculiar steel from wbiel
those tubes can be made, and which is superior to any at p
sent known to commerce. It is intended, in the first instau _^^
to erect a small factory to prove the invention, and to grant U-
censes to manufacturers upon terms that will aid rntlier thu

I conflict with existing interests.
" The terms upon which the patentees agree to transfer to tin
company all their patents for the United Kingdom is £10,00(|
cash, and £20,000 and a royalty upon the dividends paid bj
the company during the continuance of the patents; but, as i
proof of their confidence in the eventual success of the pateni
they agree to forego all payment until after the satisfactory trial
the machinery in London, and to take neither dividend no
royalty until 10 per cent, has been paid on the first issue o
£75,000 of capital. The severity of the proofs to which the gnu
barrels have been put leave no doubt whatever as to the relianot
which can be placed upon the invention. — At Paris results wen
obtained which secured the unequivocal approbation of the mill'
tary engineers and gunsmiths who assisted at the experiment*.

»at Birmingham the barrels stood more than double the ordiiui;
proof charge without being affected ; and at the London Proii;
House the tests were equally satisfactory. The direction of tba
comjiany comprises the names of gentlemen well knc
nection with commercial afiairs; and, as no payment beyond tlU
deposit of lOs, per share i^ to be made until the value of the in
vention is proved, oonaiderable inducements i
^_ capitalists."

^L Jn the forms of boilers considerable advance '.

^H during the year. Theae have principally taken the direction oi
li^btiiesa and mpid generation oi eteam, \a wsonsiAivcia -wiliti. "i

Tl

BotK^ ■ MGHTWIfiW t>1SrttABI.'B TS BOILlfiS. 18

I reqiurements of steam fire engines ; of such boileiB, see de-
^^^■iption of such engines. Of the importance of having
^^■^ boilers, a minimum water apace, &c, much may be s&id^
^^mecially in coimection with marine engineering, the saving of
^^Kd weight, the reduction of that quantity of explosive water
111 a temperature of 300" snd upwards, are aO items of consider-
:l]le improvement where they can be effected. The Mechanics'
Uagftzine on this subject obaerves: — "The actual quantity of
uoiliug water required for the safe development of a given
snioaut of steam-power in a certain time, is a question which has
n^er yet been decided, and most probably never will So lung
as the heated plates of a fine or a fire-box are in contact with a
depth of fluid sufficient to absorb all the heat imparted to them,
it seems likely enough that every neceflsarj purpose is fulfilled ;
but what the exact quantity required for the attainment of this
object is, must remain for the present, at least, a doubtful point,
depending not only on the description of plates employed, and
the quality of the water used, but on the intensity of the draft,
the quality of the fuel, and many other points of detail, too va-
rious and uncertain to permit s. very closeapproaclL to tliQoretical
limits in practice. The ambiguity of the question, or its answer,
Jiiies not, however, lessen their importance. The largest field for
the employment of steam power is found in our naval and mer-
cantile marine, and there at least does the question of the reduc-
tion of every portion of the machinery, to the smallest possible
hmit of weight, assume the greatest importance ; and very little
reflection is required to convince us that that form of steam gen-
erator is most suitable for marine purposes, which will work
safely and economically with the least possible quantity of water.
" Whatever improvements may have taken piace in our marine
engines, it is certain that they have been few enough in the
marine boiler. Since the introduction of tube flues, httle or no
alteration has taken place in the general principles of its con-
-tructiou, or in those matters of detail on which its suitability to
lis position depends. It still exists in all the clumsy m^esty of
-Lze, much as it did half a century ago. Alterations in its inter-
ii.il arrangements have been few; in ite external form still
IVwerj and for the sake of securing some important advantages,
■ ■ur enginewwAare been content to sacrifice many ttuii^ 6t\xi.'i)\'^

11 ENGINEERING FACTS. [Di>

valuaLle, Aa a result, we still fiiid our aliipB encumbered v
huge Htruotures of plate iron, costly to make, difficult to i
and of the very worst possible form for f ulfillin g one at least, i
the legitimate purposes of a ateani generator, that of sustaining
heavy presaiire exerted within it When anything above
nominal pressure is required, the engineer ia compelled to raw
to the use of stays to such an extent, that the interior of t
boiler is rendered almost inaccessible for repairs or examinatis
while its weight and cost mo seriously increased. Nor are tl
the least evils induced by its defective form, from the pecul
arrangement of uptakes and ashpits, stokeholes are, aa a Al
almost mifit for the existence of humaa beings within tbein, t
last refinements of ventilution being necessary to render the
euduraUe when situated at the bottom of a large vessel; ma
of-war or raerclwntman. The worst defect of all is found in tl
fact, that these boilers carry tons of water, to accompliali reed
attained as easily in other situations, by cwts, of the liquid.

" It is pretty certain that a given area of heating surface vr
produce nearly similar quantities of steam, by tlie oombiiBtion (
equal we^hts of fuel, whether it is covered with water to T
depth of an Inch or a foot ; whether the boiler, in iact, contain
a gallon or a hogshead; a cwt. or 10 tons. Certain rulea are^
is true, laid down by Jbjuks Watt and others, for dete
the proper area of evaporating surface, &o., wluch a well-prOpc
tioned boiler should possess. Such rules are, however, simp
absurd in a general sense ; the heating surface with whicb ti
water is in actual contact being, of course, the most importai
measure of boiler horse-power. The cubic contents of the s
filled with fluid, that occupied by steam, and the water but&o
exposed, are merely matters of detail, which can only ofFect t"
quality of the steam supplied to the engines, and have little (
nothing to do with its quantity ; save in one respect, whicb
simply, that the reduction of the quantity of water contained i
a boiler, ia always accompanied by an increase in the
production of steam, from the very obvious reason that the a,
tation of many tons of any hquid by tlie process of ebullitia
must waste power to a very considerable extent; consequent!
any reduction in its quantity is attended by a proportional
(iimiaatioa of this waste. Moat, en^ueeia ok -weU ^.'Kare of tl

m.^ *!HH!m »!tf!IIS-

^^Hk. Thus, Mr. Anostiong ststa^ in hia TsluaLle work on
^^ifeuu boilers, that* he has fouad considerable odvaotoge accroe
ifom tlie introduction of h&rd-baked bricks, within the waU-r-
^pjice in large waggon and cylindrical boilers.

" There are, however, other coneiderations besidee questions i>f
t^onomy or convonieace, which must nguLate the amuuut nt
I'.iter space allowed in a generator. Wc usually find that t)ie
'Vtent and form of the heating suriace is ita real measure, fut
more than anytliing else. And theae again depend, on shij>-
board, in a great degree on external agencies, which have nuthirjg
whatever to do with engine or boiler, oxwpt so far as they
govern their sfaapo and size. The weight of a boiler doea not,
however, depend on the greater or leaser exU-nt of watiT-spacii
which it affords, but on the heating-surfaee — in well-constructeii
boilers at least whose external superficiea bear a very small pro-
portion to the surface exposed to the direct action of the heat in
the fire-box or llues. So matter what form that surface may
assume, the metal of which it is composed should form a large
proportion of that employed in the construction of the boiler, ami
must influence its weight more thuu any other oousideratiou.
We thus meet with generators, every now and then, which di.'-
velop as much useful effect with a few gallons of water as ordi-
nary boilers do with tons. But these generators are never light
in an equal proportion; and the ardent pursuit after a boiler,
light in this sense, is really a mere waste of talent, tijiie, and
money. We are, however, speaking just now more particularly
of the marine boiler; and oJthongh we do not believe that its
weight, when empty, can be materially reduced by any change
in form or construction, we nevertheless feel ceituin that its
weight — when taken as a whole, with its contained water, as a
distinct apparatus for the production of power — is e.tcesaive, ami
that its reduction to reasonable limits should be nue of the hrst
objects of the engineer.

" That this desirable end will ever be attained while we retain
the use of flues returning over the fire-boxes, we very much
doubt, because this airangeiuent of henting aurfiice requires the
employment of an immense quantity of water, not because it is
m any way necessary to the eifeotual absorption ot t\\e b.ra.t ^co-
Ji/ccJ /b the famacea; nor jet because dry Bteam cav\wiA\» '

ENGINEERING FACTS. [Drv.

supplied without it^ but solely because large spaces are k
within the boiler which cannot be so conveniently occupied 1
inything elaa Thus, we find a distance of S in, or 12 in.
least, left between the crowns of the furnacea and the lowet

of tubes, in order that a man may find access to the 1
boxes when tbey require repairs, 3 in. of water over a fire-ba
are ample under other arrangements j and we know that the e
ve apace now provided easily accommodates many tona e
dead weight, which is of so possible service. Few engineei
who have gone into the subject in a proper spirit, will be d'
posed to assert that a boiler caa be constructed on correct pii
ciplea, which entails the necessity of carrying about, and heatii
tons of water in no wise essential to the working of the propelliq
machinery ; or that it can possess any compensating advantage
which preclude the idea of its supetsedal by genemtora of a di'
fereat form.

" "We must remember that tjiis question of marine boiler ii
provement daily presents itself to our notice in a more importai
light. However suitable the present norma! form may bo i
pressures below 15 lb. or SO lb,, it signally fails when that prnf-
sure is exceeded. Ko amount of staying can poasihly convert Sc
then into a safe and economical generator. The growing t
dency to employ high-piessure steam, the active competitioa ill
marine-engine building, render its remodelling a question of t^
utmost importance — a question which should neither be slurred oVBR

r treated with haste and carelessness. We are heretics enong
to believe that it would have been better for the mariae-etiginl
at least, that a condenser had never been invented at the ^

The possibility of attairung a paltry vacuum of 10 Ht,
1 3 lb. to the inch, has been the greatest bar to re^ progress t)
steam-engine ever encountered. Had no such thing be«n a
able, we would long since have had propeUing machinery ai
and as simple at sea as we have on our railways, where a
a and is unattainable. At sea, that which should have \
i employed as a good servant bos become a bad most
Ispoce, money, and every other consideration are given up, ii
E order to obtain results, the advantage of which is at best quib
■ inadequate to the sacrifices made.

"That the present form of marine boiler will be much li

8nn.EUs,l LOCOMOTIVE BOU.EBS, 17

retained, we doiibt; that it will be replaced by aometliing much
bettw, we believe. Indeed, uniw^s we wilfully ahut our eyes to
the light and experience afforded na by loeomotive engineering,
we can scarcely go astray. The boiler of the locomotive is, after
h:s11, the beet which haa ever been deeigaed for the development
^■BC vast power within a limited spaoe, and it requires but trilling
^Hiodification to render it as suitable fur the purposes of propul-
BW"! A^ ^^3 A^ ''^ land. The reduction of weight and apace, the
economy of fuel, the facility for carrying the highest preaaurcs
with ease and safety, which ita uae would secure, are advan-
tages sufficiently important to outweigh all cunsiilerationa of
extra expense even if tbey existed. What we want on ship-
board is aimplicity, not complication; and it is much better
lliat we should avail ourselves of what ia known and tried,
rather than introduce novelties of which past experience t«lls ua

Perhaps the best guide to improvement and perfection in any
department of engineering, wthe careful observation of al! defects
111- failures connected with such work. In boilers, although eou-
i^iderabte mystery attachea itself to their failures ur explosions, yet
Tiiost of them can bo traced to definite causes, and therefore are ex-
ceedingly useful in drawing attention to those defects in manufac-
ture or management whioh may induce deterioration or consequent
liiiluro. The experience of the Manchbbteb Steam Boium Asbo-
I lATiON in this way is very valuable, and we therefore give a full
extract from the anniial report for the year 1862, of the chief
engineer, Mr. L, E. Fletcher. In this report, the engineer says ;

"Before entering upon the detailed oonsideration of the de-
fects detected on the examiniitiona, it may be stated, tliat a
gradual improvement is found to be going on in the general
character of the boilers under inspection, as well as in the ar-
rangements of their fittings. The new constructions are marked
with more aimplicity and acceaaibility of parts and fittings, and
can be more readily attended to by the engineer in ehai-ge, aa
well as more satisfactorily examined by the inspector, and entail
mnch less anxiety in answering for their aafety. Notwithstand-
ing this general improvement, however, the defects ascertained
this yoar are more numerons than those of last year; this
be accounted for by the increased number of 'thoiovigU' exsnaxwa,- j

I

!8 ENGraiERroG FACTS. (Drv.

tions previously reierred to, which have revealed defeuts other*
"se unknown ; an adilitional iUustcatioa of tlieir importance.

''The defects discovered in boilers are mainly of two dtatinot
claasea — one relating to their construction, and the other to tbelt
condition.

" Under the first head, namely, tliat of construction, 196 i
commendations have been made, which are as follow; —

"In 153 boilers the internal flue-tubes have been recoi
mended to be strengthened by hooping.

"In 18 boilers the shells have been recoinniended to
strengthened at the steam dome by stays of angle iron, &c.

" In 9 boilers the shelb have been recommended to
strengthened at the ends.

" In 16 boilers the load on the safety-valves has b(
mended to be reduced.

" The following are those defects appertaining to the secoa
head — namely, that of condition. Of these, 85, which are e
follows, were considered dangerous: — fractures of plates aa
angle irons, 13; blistered plate, 1; furnaces out of shape, 13
coiTOBion, 37 ; defective aafety-valvea, 5 ; defective wateisgaugei
9 ; defective feed apparatus, 1 ; defective blow-out apparatus 7,

" Others not actually dangerous, but still unsatiafactory, are a
follows ; — fracture, 60 ; blistered plates, 1 9 ; furnaces out i
shape, 33 j corrosion, 270 ; safety-valves irregularly loaded an
otherwise out of ortler, 94; water-gauges out of order, 135
pressure-gauges out of order, 76; feed apparatus out of onlaq
35 ; blow-off apparatus out of order, 324 ; fusible plugs out d
order, 49 ; also two instancea of deficiency of water.

" It may be added that many of the above defects v
served at visits made early in the year, and since that time n
f them have been repaired.

" To some ft these defects more detailed reference may b

st fruitful sources of fracture in boilers is t
and contraction of their different parts, on I
)ua temperatures, which are caused in ma
n all, by imperfect circulation of the water.

a.] IHPKOVEMENT OF BOILERS.

^^^"This has l:e«n. kept in view so coiistautly iq pi'tivinns rajiorts,
that little more now is neceasary thaji an euumenttlon of any ad-
ditional facts, which have lately come uuiier notice.

" It may, therefore, briefly be stated that grooving still con-
tinues to manifeat itself in double-flued boilers at the tube angle
irons and end plutea, more especially at the fumaoe month; and
is more active in proportion as the end plates are rigidly stayed.
Ill uo class of boiler, however, is this action f'lund to be so de-
stnictivo aa that in which the furnace tubes are brought so close
together; that there is not room for the angle iron at either end
of the flue to be carried completely round tlietn ; and is, there-
fore, supplemented by what is called a 'siiddle- plate,' which,
with its complement of the two partial angle iron hoops, forms
a 'spectacle-piece.' These ' saddle-piecea ' are found to groove so
deeply that in some cases the whole thickness of the plate be-
coraus eaten throujjh. There is no satisfactory cure for this but
iheii entire removal, and the tapering down of the fliie-tubes nt
the mouth, so as to increase the intermeUiate space.

" Channelling at the transverse seams at the bottom of the shell
■ it' internally iired boilers, is still met with. It geuemlly isdiscover-
I'd in the bottom external flue.on the outside of the plate immediatt-
ly at the edge of the overlap, beiiLg deepest at the centre or ' keel '
line, and dying out in about 15 inches on each side, but very fro-

I ii/ntly in much less. In one instance, however, it was founil

II the internal surface of the plate, and to be situated as high
IS the side wall on which the boiler was set

" On the whole a gradual improvement, both with regard to
i.'hannelling at. the bottom seams, and grooving at the end plates
xwl angle irons, is taking plaee in the hollers under inspection.
I'hia improvement is due, with regard to the former, to the more
jTieral adoption of means for heating the feed water, as well as
" • the boilers being now more frequently set, so that the heat
u<-m the furnace flues passes immediately under the bottom, and
then lastly along the sides, by which means the circulation of
the water is improved ; while, with regard tu the latter, the im-
provement is due to the fact of the end plates being now leas
rigidly stayed, and thus, as has been stated in previous reports,
having room to ' breathe.'

" Boilers with two furnaces rMiuiing into a single oval flue,

F

16 ENGINEEHING FACTS. [Div. I

supplied without it, but solely because latge Bpaous are lef
within the boiler which cannot be so conTenientl; occupied b;
anything else. Thus, we find a distance of 8 in. or 12 in.
least, left between the crowns of the furnaces and the lowi
rows of tubes, in order that a, man may find access to the &
boxes when they require repairs. 3 in. of water over a fire-boi
are ample under other arrangements; and we know that the e
cessive space now provided easily accommodates many tons (
dead weiglit, which ia of no possible service. Few enginoed
who have gone into the subject in a proper spirit, will be d"
posed to assert that a boiler con be constructed on correct piiB
cipled, which entails the necessity of carrying about, and heatiiii
tons of water in no wise essential to the working of the propollinj
machinery; or that it can possess any compensating advantage
which preclude the idea of its supersedal by generators of a dil
ferent form.

" We must remember that this question of marine boiler i
provement daily presents itself to our notice in a mure imports
light, However suitable the present normal lorm may be fu
pressures below 15 lb. or 20 lb., it eignaUy fails when that p
sure is exceeded. So amount of staying can possibly convert i
then into a safe and economical generator. The growing te
deucy to employ high-pressitra steam, the active competition
marine-engine bidlcling, render its remodelling a question of t
utmost importance — a questionwhichshould neither be slurred ove
nor treated with ha.'jte and carelessness. We are heretics enougt
tu believe that it would have been better for the mariue-engiiU
at least, that a condenser had never been invented at the time it
Wiis. The possibility of attaining a paltry vacuum of 10 lb, OC
1 3 ll>. to the inch, has been the greatest bar to real progress &A
steam-engine ever encountered. Had no such thing been attain- J
able, we would long since have had propelling machinery as light I
and as simple at sea as we have on our railways, where a vacuom I
was and is unattainable. At sea, that which should have been ]
employed as a good servant has became a bad master, to whom J
space, money, and every other consideration are given np,
order to obtain results, the advantage of which is at best qwi

leijoate to the sacrifices made.

That the present form of marine ^V^i w^ 'W mnO^Nc

lained, we dotiLt; that It will be replaced hy sotnethlog much
Setter, we believe, Indeod, unlesa we wilfully ehot our eyes to
the light antl experience afforded ua by looomotivo engineering,
we can ecBrcely go antray. The boiler of the liKomotive is, after
M, the best which has ever been designed for the developniHnt

f vast power within a limited space, and it requires bnt triiliug
; u< idification to render it as suitable fur the purposes of pruput-
'Mil at sea as ou land. The reductioa of weight and space, the
-I'liioniy of fuel, the facility for carrying the highest pressure*
'Aiih ease and safety, which its use would secure, ore advan-

il;ei8 satficiently important to outweigh all considisratiuna of
■ \tra expense even if they existed. Wliat we want on ahip-

I'iird is simplicity, not comphcation ; and it is much better

imt we should avail ourselves of what is known and trim],
.jthei than introduce novelties of which past experience tells us

Perhaps the best guide to improvement and perfection in any
1 li^partment of on^neering, is the careful observation of all defects
111' failures connected with such work. In boilers, although con-
^iilerftble myatery attaches itself to tiieir failures or Bxploaiona, yet
must of them can be traced to definite causes, and therefore are ex-
ii)t>dingly useful in drawing attention to those defects in manufac-
I 'ire or management which may induce deterioration or consequent
I iilurp.. The experience of the Manohksteb Steam Boileh Ashu-
i iTioN in this way is very valuable, and we therefore give a full
xtraet fmia the annual report for the year 1862, of the chief
iigineer, Mr. L. E. Fletcher. In this report, the engineer says ;
"Before entering upon the detailed consideration of the de-
1 lis detected on the exaintnaitions, it may be stated, that a
gradual improveniont is found to be going on in the general
uliarocter of the boilers under inspection, as well as in the ar-
rangements of their fittings. The new constructions are marked
with more simphctty and accessibility of parts and httings, anii
can be more readily attended to by the engineer in charge, as
well as more satisfactorily examined by the inspector, and entail
EQuah. less anxiety in answering for their safety. Notwithstand-
ing this general improvement, however, the defects ascertained
this year are more numerous than those of last jea.! •, tVift ■ma.^
Iti' aeooanied for by the iacreased number of ' thotongV examYAn).-

i

I

I

I

18 ENGINEERING FACTS. [Drv. I.

tiona previoasly referred to, wliich. have revealed defecta other-
wise uuknowa; an additional illustration of their importance.

"The defecta discovered in hoilers are mainly of two distinct
ctaasQS — one relating to their construction, and the other to their
condition.

"Under the first head, namely, that of construction, 196 re-
commendations have been, made, which are as follow; —

"In 153 boilers the internal flue-tubea have been «
mended to be atrengthenod by hooping.

"In 18 boilers the shellfl have been recommended to ba
strengthened at the steam dome hy stays of angle iron, &c

"In 9 boilers the sheila have been recommended t
strengthened at the ends.

"In 16 boilers the load on the safety'Valves has been n
mended to he reduced.

" The following are those defects appertaining to the second
head — namely, that of condition. Of these, 85, which a
fijllows, were considered dangerous ; — fractures of platea and
angle irona, 13; bhstered plate, Ij furnaces out of shape, 12;
corrasion, 37; defective eafety-valves, 5; defective water-gauge^
9 j defective feed apparatus, 1 ; defective blow-out apparatus, 7.

" Others not actually dangerous, but still unsatisfactory, are i
follows; — fracture, 60; blistered plates, 19; fumacea out
shape, 33; corrosion, 270; safety-valves irregularly loaded and
otherwise out of order, 94; water-gauges out of order, 13B;.
pressure-gauges out of order, 76; feed apparatus out of order,
35 ; blow-off apparatus out of order, 224 ; fusible plugs out of
order, i9 ; also two instances of deficiency of water.

" It may be added that many of the above defecta wen
served at visits made early in the year, and since that time man/
of them have been repaired,

" To some cf these defects more detailed reference may Im

I" One of the most fruitful sources of fracture in boilers
unequal expansion and contraction of their different parts, on ae-
aaiiiit oi the various temperatures, which are caused in many
ases, though nut in all, by imperfect ciictt\aJAon o? ".he water.

^HoiLKBsO IMPKOVKMENT OF BOILERS. ^^H

^^K "ThisIiHS been kept in new eo constantly in previous l&fKf^.
^^pot little more now b necessary thiui an enumeration of laij art-
^Hptionnl facts, wbich have lately come nuder notice.
^^B " It may, therefore, briefly be stated that grooving etill coa-
^^■liuiea to manifest itself in doable-llued boilers at the tube nngie
^^■Das and end plates, more espBcially at the fumncc mouth ; and
^Himore active in proportion aa the end plates are rigidly stayed
^^K no claas of boiler, however, is this action found to be au de-
^^■tuctivB as that in which the furuoci! tubes ore bmuglit so close
^^^Qther; that there is nut rt.<um for the angle iron at either end
^BF the flue to be carried completely round themj and is, there-
^Tbre, supplemented by what is called a 'saddle-plate,' vhich,
with its coinpleraont of the tno partial angle iron hoops, forms
a 'spectacle-piece.' Theae ' eaddle-pieces ' are found to groove so
deeply that in some cases the whole thiekuees of the plate be-
comes eaten througiL There ia no satii;factory cure for this but
their entire rem'ival, and the tapering down of the flae-tulx-s ui
the mouth, so as to increase the intermediate space.

" ChanneUing at the transverse seams iit the bottom of the shell
iif tntemally hred boilers, is still met with. It generally is discover-
ed in the bottom external flue, on the outside of the plate immedialb-
ly at the edge of the overlap, being deepest at the centre or ' keel '
^^ne, and dying out in about 15 inches on each side, but very fre-
^^Kently in much less. In one instance, however, it was found
^^■l the internal surface of the plate, and to be situated as high
^^b the side wall on which the boiler was set

" On the whole a gradual improvement, both with regard to
vbannelling ai. the bottom seams, and grooving at the end plates
and angle irons, is taking place in the boilers under inspection,
s improvement is due, with r^urd to the former, to the more
jBeral adoption of means fur heating the feed water, as well as
I'tiie boilers being now more frequently set, bo that the heat
a the furnace floes passes immediately under the bottom, and
ten lastly along the sides, by which means the circulation of
B wa.ter is improved ; while, with regard to the latter, the im-
pivenient is due to the fact of the end plates being now less
Tigidly stayed, and thus, as has been stated in previous repdrts,
having room to ' breatha'

" BoDers with two /unices running into a suift^e o\!\ W:

I

I

211 ENGINEERING FACTS. [Div

eontiiiiiiag a numlier of vertical water talies, liaye the advuntaga
of El more rapid circulation of the water, which is decidedly cal-
culated to prevent hoth transverse channelling at the ring seanW'
and grooving at the angle irons. There are, however, but ft
small number of these boilers under inspection, in proportion to
those of the double-flued class; but, as far as nbeervatioa
been made, they oertaiuiy appear to compare favourably, on ths
above points, with their competitors. Water tubes have
been added in a few cases to onliiiary double-flued boilers, being
fixed behind the fire-bridge with a view to promote circulation,
while, with the same object, a new boiler has lately been brought
out, in which water pockets or mid-feathers at varying angleft
are fixed in the flue-tube, with a view of securing it against
collapse, and at the same time promoting circulation of the

" Other eases of fracture have occurred from fixing angli
strengthening hoops to flues in an improper mannei'. This has
been so faliy gone into in the printed abstract of the monthly
report for June last, and whicli was circulated amongst the
bers, that nothing need now be added beyond stating that sever*
al additional cases have since been met with of plates at thb
crowns of furnace tubes beooiaing burnt and cracked, when the
thimbles or ferrules between the plates and angle iron hoops,
explained in the above report, have been omitted.

" Other cases, again, of fracture, have been caused by the fluft*
tubes and shell being bound together by a cross stay in the mid-
dle fff tlieir length, when, from the unequal expansion of the two,
one has injured the other.

" One case of fracture has been met with in an externally fired
boiler, which occurred at one of the transverse seams of rivets,
from the sudden cooling of the plates, by the too hasty introdue*
tion of a quantity of cold water immediately alter blowing out,
while very similar injury has arisen at the transveree seams over
the fnmaoea in other externally fired boilers when in work, and,
in addition, several of their plates have both bulged and blis-
tered. Boilers externally heated by the flames passing off from
iron furnaces have been found to be specially liable to start at
the seams, and crack at the rivet holes, at the point where tiia
ffnme impinges.-

BeiusRB.] BLISTEKED PLATES, 21

B "A boiler with twoinlumal fiimacea, as wtU as mi exti-nial
one lieneath it, added with a view to promote ciroulatiim of the
water, waa foimd to bulge in the plate of the externnl bIicU over
the fire, wLile tlie internal furnace tubes remained uninjurfd.
It is thought that this boiler, from the fact of its uombtutii^
withia itself the two classes of firing, viz., internal and external,
affords an apt opportunity of comparing the merits of the twn
systems, while the result just recorded is fully borne out by u,
luore extended observation of other boilers.

BMSTEHED PLATKB.
" This eubject has been somewhat anticipated uodec the pre-
vious heading, and it will now, therefore, be only necessary to
point out, that the feet of plates, by good makers, being liable
to blietei unawares, and which previous examination evidently
falls to detect, bLowb the importance of not hazarding an explo-
sion npon their soundness. Thus tlie strength of no unassisted
plate, exposed to the action of the fire, should be relied on; and,
consequently, it becomes most desirable that fui-uacea should, in
every instance, tie stayed either by flanged aeanis, or witli hoops
of angle iron, T-iron, or otlier advantiigeijus form.

" The general causes of shortness of water, from which over-
heating and injiiiy to the furnace crowns ensue, are found to be
as follows : —

1. The direct neglect by the engine-tenter of the feed appa-
ratus, which is too obvious to need remark, and too glaringly
careless to be otherwise than eseeptionaL

2. False indication of the glass water-gauges.

3. Loss of water at night on account of leakage of the blow-
i.>ut appui-atuB, sometimes from it^ being carelessly and imperfectly

4. The lighting of fires by nigbt watchmen, and others, with-
■iit any water in the boiler.

5. Blowing the water out of the boiler with the fir? still left
,11 it.

" An efficient low water safety valve, which would — on the
inking of the water below its proper level — rt;li6\e t\\e

bhe^fl

r

I
I

22 ENOINEERING FACTS, [Dii

of the stBam, would evidently save the furnaces tinder aome o<
the above eircuniBtances, though not under all.

" It should be added, that some furnaces are out of shape
from their first constructioUj being found on actual measurement
to be as much so as one or two inches, merely from carelew
■workmanship, which passes unobserved until detected on inspett-
tion. This inaccuracy considerably weakens the flues, especially
■when the major axis is horizontal, since the natural tendency o
al! furnace tubes is to collapse vertically.

" Goriwon is found to be going on in all boilers more o
and it will be seen that the greatest number of dangerous delbets
in the preceding het are to be found under this head, A
instances may be given, In one case, a boiler set upoa a
feather wall, 15 in. thick, had a chanuel eaten right along i
about 8 in. wide, which ran down the centre of the seating^
while the plate at the edges of the brickwork appeared quits
sound, and the danger conflequantly passed for si
pectsd. In a second instance, with a mid-feather 2 ft wide, tha
plate was found to he eaten almost through from nearly o
of the boiler to the other; while in a third, where lune had been
allowed to come in contact with the boiler at the mid-feather,
the plate was completely pulverized, and could be carried vwaj
in handfuls. In a fourth case, a vertical tubular boiler had h
placed close to a wall, one part being in actual contact Dam^
in the brickwork set up corrosive action in the plate, which,
being concealed by the position, went on undetected until th«
metal was completely eaten through, and a piece blown oat hj
the pressure of the steam. The original plating of the boilep
was thick, the pressure low, and the corrosive action local, only
afTectiug a surface of about 12 in. square, so that the rent did
not extend.

" A fruitful source of corrosion is found in the leakage of
hlow-out pipes at their attachment to the shell, while in some
cases the pipes themselves are fractured, and continue a
aome time unawares, the leakage meanwhile playing on the bot-
torn plate, from wliioli corrosion necessarily ensues,
"£xfunplea of corrosion miglit ^ iivaU.\.v^e& S

k

BoherbJ SAFETT VALVSS.

iiuugh, however, has been said to show the tinpurtiinc« of ha*
bg oU ports of the boiler acce«siblfl to examination, the fliu
sufficiently capacioaa, nnd the ieatinga as narrow as piissihle, on
aIso of having the brickwork removed occasionally, at all event
in places, bo oe to ascertain the condition of the plated, eiDce t
conclude Uiat the parts concealed are in the same cunditiou i
3se in view, has been fonnd in practice to be foUacioni
" The examplae of corrosion, previousiy referred to, have ai
been extetnal, (uid caused in every case by moisture, amiog
either fi-oiu leakage or dfunp in the fine. Internal corrua'
not generally so dangerous, and arises from acidity in the waten
Many members are now using carbonate of soda, and all thoM
■vho do so speak highly of it Even the Manchester tomi'S
ffater is improved by the introdnction of a slight quantity.
This water is not found to be dangeronsly corrosive, but to
ipecklo ^e plates over minute indentations, in some cases depi>-
aiting small scales, like miniature flattened walnuts, about thres-
quarters of an inch in diameter, and one-eighth of an inch thick.
Theae, on being severed from the plate, leave behind tbem shal-
low prints on its sur&ce. One firm, having several SO-hora»
power boilets, and which are fed with Manchester town's water,
Qsos half a pound of soda in each per diem, and finds this quan-
tity sufficient to neutraliKe the acidity.

DEFECTIVE SAFETY VALVES.

" Iteck]esB or even careleas overloading is now seldom if ever
met with in the boilers under inapection, though some
have come under notice of most defective arrangements in new
boikn, the safety-valves being placed on the ateam-ptpos instead
^f directly on the shell, eo that the communication between them
was contingent upon the junction valve being open.

" Many safety-valves are found improperly loaded, that
securely so, and with loose irregular weights. Importance is at-
taclied to safety-valve levers being loaded, with but a singh
suitably-adjnst«d weight at their end.

"The attachment of internal loading to dead- weight safety-valvi
has, in some casus, been found must insecure. This is a point,
from the conceahnent of tjie weights and links mthiiv tUft toUwj
which ialikelyto escape attention, though S6n0ttaaC8.\>i\a%'9'O^'

ENGINEERING FACTS. [Div. I.

in a oolilineii Loilor house in case of the valves suddenly

t treaking loose. Of internally loaded dead-weight valves, thofw.

a the safest whieh ate boxed-in and fitted with u haiid-lifliing,

Llever, and a discharge pipe fur the waste steam.

WATER GAUOKS.

"The recommendation previously given to fix duplicate water
jpLUges to evety boiler, and to have the passage in the uecks aa
EUige as x>ossible, can only be repeated, in the present instancy
rith the additional force which another year's inspection gives,.
■And many furnace crowns would have been saved by the timely
<:adoption of these simple precautions. The taps of glass water-
I'gauges are almost always found to leak; tliia cau be greatly

■ remedied by having them fitted with nut-glands packed with s
1 little cotton, while the grit, wiiich so soon cuts away the plugs,
f would be much leaseaed by the adoption of surface blowing-out

PRESS URB GAUGES.

"All the pressure gauges fixed to the boilers under inspection
B«re checked by a standard indicator at each of the inspectoi'i

■ visits, provided that the boilers are fitted with the necessary tap.

■ Thus the accuracy of luoat of the pressure gauges passes

■ xtantly under review.
"Generally, they are found to indicate too high a pressure,.

■ but, in some cases, as much as from ten to fifteen pounds too
^ttle ; the first error leading to their being disregarded, and the

E««cond to actual excess.

"The pressure gauges under inspection are, with but a few

■txceptions, of four classes, namely, the natural mercuiial column

, gauge ; the mercurial differential gauge ; the dial gauge ; and tliu

compressed air gauge.

" The natural mercurial column gauge stands first upon the
L list for accuracy, as its simple and direct construgtioa would
I 'clicate.

"Tlie differential mercurial gauge is of inverted syphon oOn-
[letruction, the short leg teing of larger diameter than the long.
I. fine, and thus the mercury has less travel in the former than
Lthe latter. The indications of pressure ore read off from thft
fiuH leg, which considerably reduces ttie \eugi\i. i>t tlw

Bl,nw OFF AI'PAnATCS. 2S

Sale of poirnda, and. those of tiie best olas* of this gaiigw are very
1> ;^ble. In one class of dilferential gaoge, however, Ihe mercary
' iilers the glass indication tulH<, whicli becoiiiM very much tils'
' 'loured in coiiBequence, and, in some cases, quite opaqup ; while.
il the same time, the gkas etnode off so iar from the iaiiex &ce,
;iiaC it call only be reud accurately when the eye is placed on h
1 1 vol with the upper Burface of tlie mercurial column. In an-
other class of this differential gauge the mercury does not unk-r
t.lie gia^ tube at all, but the pressure is indicated by a floatiu}^
jiointer, so that no discolouration of the glass takeo place, ami
tiji? gauge is always legible.

" Dial gauges are very compact, and can be fixed din^itly in
fbout of the boiler, just in sight; whOe those of the best class
are very legible; care should be taken, however, not to fix them
*too near the boiler face, or else to put a piece of wood betwenn
the two so as to prevent their becoming heated, oi' otlicrwise
their indications will be affected.

"ThH compressed air gange, in which a syphon column of mer-
cuiy, as a piston, acts upon on ur cushion, is found to be unt-
vetsallj incorrect, and is quite nnworthj of confidence.

"In conclusion, while the natural meicurial column gauge must
be allowed to stand the highest for abstract accuracy, yet the
best description of the mercurial differential column gauge, aa
well as that of the dial gauge, arc but slightly inferior to it prac-
tically, and are more easUy read ; while the dial stands pre-eminent
fur compactness, especially at high pressures, which becomes of
importance in a long series of hoilera, when each is fitted, as it is
iilways desirable sliould be the case, with its own independent

i

ff-OUT APPiRATDa.

It has already been stated, under the bead of

much injury is &equently done to the bottom plates of

boilers by defective joints of the blow-out pipe; to remedy

which, a short block should be riveted to the boiler, and the pipe

Wted to it instead of direct to the shell. These pipes, which

generally of elbow-shape, should not be bound by the brick-

the settlement of the boiler is apt to stiBiii ttveai,aind.

iw oaotared m whiuh they have beun fiofitWKd. u^ i^luwr

I

K othe
^V reanlt

ENGINEERING FACTS. [Div

From this, in one instance, considerable
enaueii ; and in another, not under the inspection of this
ciation, in which the iractwe was sudden and complete, scalding
resulted to two or three persons.

"Many blow-out taps are dangerous to use for want of suitable
discharge pipes to carry off the waste water, and, in some boilers,
the water spaces have been found to be completely choked with
Bfldiment, from neglect of the most simple precautions with
gard to the use of the hlow-oat apparatus. This subject has
Qstantly alluded to, that repetition would be lfldioa%
though, perhaps, hardly unnecessary ; it will, therefore, only b*
added that brass gland taps, recommended in previous re]

3 still found to give satisfection, and to be more certain :
their action than, either sluice or mushroom valves.

INCRUSTATION.

" Some advance has been made during the past year in ti
prevention and removal of incrustation, although much yet i
mains to b« done, It \% Via frequently concludecl that incrOBta-
tion and corrosion are not to be found in the same boiler, and
that the plates beneath the scale are protected. Such, however,
is by no means found to be universally the ease, and freqnetitly,
on removing the scale, grooving, or other evidence of corrOMon,
is discovered on the surface of the plate beneath it. An inspect
tion of a boiler, therefore, coated with incrustation, must tdwaya
be unsatisfactory^ not to mention the injury to the boiler itsal^
as well as the loss of heat that results from it.

"The remedy adopted for. this evil, in marine boilers, namely,,
' surface blowing-out,' has been during the past year frequently
brought before the attention of the members, and a drawing
made of a simple nn<patonted arrangement, and placed at their
dispoeaL A very considerable number have availed themselves
of this, while as many of the manufacturing engineers as hove
wished to do so have furnished themselves with copies. IJii
consequence of this, several of these scum pipes have been ap-
plied, the exact number is not known, hut one firm an
others may be mentioned, who have fixed one of these a
pipea to each of their nine boilers, and with the most afttisfeotoij
reanlta.

"This i

COSSTRUCTIOjr OF BOILERS

! not, however, the only descriptioTi of scQtu pipe
lopted. The subject of ' sur&ce blowing-out ' hns been token
j) by others, and two varieties uf apparatus patented, uid muiuh-
>bat general!}' introduced. It ia thought that this divenity
"1 rather prove of advantage than otherwise ; and now that
i general principle of 'sur&ce blowing-out' hae been called
intion to, the more individual ingenuity ia directed to the de-
f the apparatus the better. A more minute reference to tlin
nction of these ecnm pipo« was made in the monthly ab-
t of October Inst ; and now that these three classes have
'a operation for some time, it ia thought that the retmlts of
leir working may shortly be made a matter of comparison,
^bicb, as soon as opportunity ofiers, will be communicated lo
e members.

soda, for the preyention of incrostation, is found
of considerable advantage, and increasingly adopted. It is,
however, better introduced in small regular doses, than in large
infrequent charges. In many cases there might be fitted to the
suction pipe of the feed putnp a funnel mouth by means of
which the requisite charge could be introduced to the boiler
without difficulty ; its rate of ingress being regulated by a tap be-
tween it and the suction pipe. In some cases a separate feed
puinp has been adopted, fitteil with a small cistern containing a
day's supply, and this arrangement has been found to work niust
satisfactorily.

" In conclusion, there are liut few cases of inci'ustation which
9 nse of soda, combined with regular blowing-out from the sur-
B of the water, will not check.

COKSTEUCIION OF BOILERS.

" The consideration of the previous defects, to which the
nlers tmder inspection have been found to be liable, will, it is
1, prove of assistance to merobera wishing to lay down new
, as well as tt> those whose business it is to construct

is thought, however, that a further service yet might be
iDdeFed. Such ample opportunity has been enjoyed of seeing
jrk, as we]] as ot exsraining while at rest, CQ\isa4fi,'«W\.ft
mbara ami vatietiea of boUaTa, and atich fi\\l uiioTmB.\.\yu Yaa

EJJGINEEEING FACTS.

[Dt.

been culkcted with i-egard to tbem by the asBocktioti, that
IB thouglit if the beat proportions were ooUatedj and put together
in the form Bomewhat of a specification, it would provo of mow
assistance still than observations and analyses ol defects alone
not by any means a minute and technical specification, but
ayatematic explanation of such proportiouB as have been found ta<
exist in those boilers, giving the best reeulta, and needing the
least repair. It was intended to include this
port, but, finding that it could not be given
served for insertion in the printed raontbly reports wliich circulate
amongst the members.

KXPLOSIOKS.

'■ It is to be regretted, that no means exist of ascertaining tho.
wh(fle nuniber of steam boiler explosions that occur throughout
the United Kingdom, and there can be no doubt that many a
never recorded at alL There are known, however, to have o&
curred during the last year, no leas than 30 explosions, froia
wbicb, at least, 87 peraous hare beea killed, and 89 iqjuied.
Of the number of Kves lost by some of the above, i
could be obtained ; while, from one of them, as many a;
sons were killed, and 13 injured; from a second, 13 we
and 24 injuredj and from a third, 6 were killed, and
" The following list gives the description of boiler
the explosions have occurred, with the number of each class, as
well as of the persons killed and injured: —

Four haystack boilers — 13 persons killed, 5 others injufed.
Six plain cylindrical e^-ended boilers — 6 persona killed, I

others injured.
Throe iron-works' boilers — 47 persons killed, 44 others in*

jured.
Three plain single-fiued Cornish boilers — 2 persons kille^

3 others injured.
Two plain double-flued Lancashire builers — 4 persons killed
Three locomotive boilers, of tubular construction — 4 p
killed, 5 others injured.
I One agricultural boiler, of tubular portable construction—
[ persons killed, 4 others injured.

L Ojie iitchen-TfUige boiler — 1 peiaun \ul^e^

D acconnfe.
29 per-

ire killed,
i injured.
f to which

BOn^B EXPLOSIONS »

^ Also sevun other boilers, of the conatniction of which no re-
hable iiiformatioQ coiild be ohiaiiied, and tnim the explo-
sion of which, 7 pereoaB were killed, and 22 others
injured,

" The haystack boilers, referred to above, werp eslemally fireil,
and exploded through the failure of the part exjiosed to the ac-
tion of the fire.

" The plain egg-ended boilers, fired underneath, were found,
i :i all oasea, to have exploded from the rending of the transverse
-'.ittuB of rivets. One of these hoilera eiploded at the bottom of
L coal mine, and in another case three hollers working side hy
■^ide exploded simultaneouBly. Details of all these have already
been reported in the monthly abstracts for February, March, and
August, respectively, so tiiat further particulars need not now be
given.

" The iron-works' boilers were all heated by the fianies passing
off from the iron fiirnacea, which played not only upon the ex-
ternal shells of the boilers, but also through their internal flues.

"The first of these was what is termed an 'upright furnace'
boiler, in which the flames, passing off from sometimes as many
OS fonr iron furnaces, impinge npon the exterior, and then pasa
into an interior descending flue. In this case the crown of the
'ie*tcending flue collapsed &om original defective construction.

" The second explosion occnrred to a precisely similar boiler,
liut in this case the external shell gave way at the seams upon
nhich the flames from the iron furnaces impinged.

" The third boiler was a plain single- fl.ued ' Cornish ' one, fired
■■xtemally hy the fiames parsing off from two iron furnaces, and
internally by those passing off; through its fl.u6 tube, from an-
other. The explosion was caused by collapse of the internal
flue-tube, arising from defective construction, and might have
been prevented had the flue been strengthened, either witli
flnnged seams, or hoops of angle iron, T i"^n, or other suitable

" Each of the three iron-works' boilers was personally examined
subsequently to its explosion, and fuQ particulars were given in
the March, April, and December monthly abstracts.

" Of the three explosions which occurred to pluln ' CotnvaV
bailer^ one was caused by collapse of the flue-tvibe, cotiati^^xA.

ENGISEERING FACTS

[Div. ]

I

upon ahortiieaa of water, Thia appears to have been caused 1
carelessness, the gange-glasa having been broken. The shell (
the boiler was uninjured, and tbe only damage done was b; tlid
percussive action of the steam and water, in a direct line witlj
the furnace tube.

"Of the other two no reliable information could be obtained j
they are reported, however, to have failed at tbe front end-plato;
"Both the esploaiona, which occurred to boilers of tbe pl^H
double-flued 'Lancasliiie' class, were caused by esternal c
sion of the plates, which wore so eaten away in one case as to b
reduced in thickness to the sixteenth of an inch, and
other to that of a sheet of paper.

" One of these boilers was under the inspection of this asso-
ciation, but the opportunity had not been afforded to its inspec-
tors of making the regular annual 'thorough' examinations, th«>
importance of which has been so repeatedly called attention t
in the reports. This subject was gone so fully into in tfa
monthly report for July last, shortly after the explosion haii*
pene<l, that it is needless to repeat the details here; white thft
particulars of the other, which also was personally examined, n
be found in the monthly report for last December.

" The locomotive boilers, in every case, exploded from thinning
of the plates, caused by internal corrosion, it being a generaJl
practice in the management of locomotives only to make a'
thorough internal examination of the shells of tbe boilers, whfui
the flue-tubes are renewed. This, in some cases, has allowed a
interval of as much aa seven years to elapse between one exami-
nation and another, during which time the boiler has beea
working in a state of complete uncertainty, the actual conditioi)
of the plates being unknown. The use of the hydraulic pressure
is objected to by several locomotive engineers, thoi^h not by all j
it ie a point which bus provoked a good deal of discussion, and ii
too lengthy to enter upon on the present occasion. It may, how-
ever, be stated, in brief, that no case has been met with, ii
experience of the association, in which injury has resulted fronv
the judicious apphcation of this test, and also that no opportunity
will be lost of contributing any information on the subject that thK
, experience of the association may afford. It is one of consider'
^We interest, and affucts the safety of the whole travelling pablia

8.1 BOILER TXPL0SI0S9.

r The kitclien -range boiler exploded fioin accumaUtt^d preaBiire,
h taps of both the iulet and outlet pipaa b^ing closed at th«
e tiniti, in cooaeqnence of which Uiere waa no escape for tha
ni, theru being no safety-valve,
" Of the cause of the explosion of the agricultural ]>ortabl«
a well aa of those whicli occurred to the remaining seven
It the bottom of the list, no reliable information has been re-
leived, while the distance at which nearly all of them happened
T'l-ecluded personal examination.

'■ The causes of the above eTplnsions may be ayatomatiied us
f fill lows: —

"Of 30 explosions, which happened during the year 1862, II
I occurred to externally fired boilera from failure of the pUtes «x-
] pused to the action of the fire ; 3 resulted iirim internal corro-
L, and 3 from external; in addition to which, 4 were due to
iuipropei' original construction, one to shortness of water, and
another to accumulated pressure througli want of a safety-valve ;
while 7 occurred at a distance which precluded a pereonal inves-
tigation of their causes, at the same time that no reliable infor-
niatioQ could be obtained with regard to them.

" It may be added that the explc^ion which occurred to i
double-flued 'Lancashire' boiler, and &om which one life wu;
lost, is the third fatal explosion which bos happened to any of
the boilera under the inspection of this association, since it
establishment eight years ago; to which should be iwWed thre
cases of collapse of fumace flues, not attended with any ecriou
consequences, and which arose^ in two instances, if not in al
three, from shortness of water. During this period 712 danger-
ous defects have been pointed out in the boilers under iiispectio
&om which serious injury might have arisen in each case; while,
upon limited inquiry only, it has been found that no less
313 explosions have occurred in that time to boilers not i

Suspection of this association, which have been attended with
OGB of 472 lives, in addition to serious injury to 513 pei
and considerable damage to property,

"The depressed state of trade during the past year baa so dL
organised the ordinary working of most of the tnOia, \,\«fc v't \vJ

r

W t

ENGINEEKING FACTS. [Drr. T.

been found impossible to draw up a reliable comparative table of

mic duty of the engines. Indicator diagrama alone,

however, from most of the engines under inspection, never aT

the necessary data for correct comparison, since so much ateam

drawn off for purposes other than that of motive power. It
becomes, therefore, highly desirable that water metres ehoulcl
be fixed to each series of boilers, so as to asceitain the amoui
of water evaporated. This would enable a comparison to \
made of the evaporative power of dillerent boilers, and of thrf
valne of different coals, while at the same time the diagrama
would aiford an indication of the working of the engines.

"Two pair of engines, bidlt during the past year, have had
their cylinders fitted with steam jackets; and a superheating
apparatus, for raising the temperature of the 6t«am in its pas
between the boiler and engine, has been introduced in twi
three iustances. The objeot of both these arrangements is eoo'
nomy of fuel, and it is intended, as soon as possible, to inveati'
gate the results obtained, in order to communicate them to the

"A ' surface- condenser' is being constructed for a pair ol
beam-engines, and will, it in expected, be put to work early this
year. ' Surface eondensation' is the most radical preventative
of incrustation, since, whatever the character of the condensing
steam may he, this condenser returns to the boiler distilled water
the same quantity, with the exception of a small amount of
waste, being used again aiid again. There are many oases in
this district where this will prove valuable] and the results of
the application, in the present instance, will be a matter of con-
siderable interest to many of the steara-users of the district

coNCLUsioH.

"A very brief recapitulation may be allowed, in conolusioii, of
some of the points attained during the past year.

" ' Surface blowing - out ' has made considerable progress.
' Steam-jackets,' so long discarded in this district, have been re-
vived, and ' superheating' introduced, while a ' surface-condenser'
is about to be applied

"Althirugh these arrangements ate not in general use hem,
UiiifMre been fully tested elsewhoie, aad it ^ tlwugjit

^■^ruxa.] STEAM JACKETS, SUPEHHEATEltS. 33 ■

^mnich may be gained hy isijiorting, as it were, into this disti'ict I
the engineering experience of others. For instance, the 'steam- %
JKcket' haa, in combination with the use of highly-expanded
steam, been the principal element in the attainment of that ecn-
numy for whkh the Cormsh engine hiLS for bo long since been
notorious, while 'surface hlowing-out' and ' Burface-condensa-
tiun,' aa well as 'superheating,' are due to marine engineering
jiractioe, which has developed a higher economic result than that
generally obtained in this district.

" Although it is true that all roally sound and beneficial me-
chanical arrangements, practised in one district, will, in time,
purely find tbeir way into and secure for themselves adoption in
"thers; yet it is thought that tihia association can do much to
liHsten this process — too frequently a tanly one — by circulating,
upon these points, infoimation amongst its nlemhers ; and tu
assist in doing which, as far as it hes in my power, will always
he regarded by me, not only as a duty bat a source of satisfactinu
and pleasure.

" It is trusted that, during tho present year, the mechanical
ii-3iigement3 just referred to wiU be fully tested, and a. genend
' iifidenoe and adoption secured in this district, for such of them
I- proTe worthy of it; so that the desire expressed at the con-
' Lusion of the last annual report may be realized, namely —
■ riiat no year may ho allowed to pass without a decided mark
■i progress being clearly stamped upon the engineering practice
"i the district, by this association.' For the aucompUshment of
this, however, the co-operation of the members ia absolutely ne-
ci.i-ssary. Comparative returns of the working of engines cannot
he made, unless the members have their engines indicated; nei-
tlier can the eonsuiaiition be calculated, without aceurate returns ;
(■>:■ the evaporative power of tha boilers arrived at without tlio
■ P|riication of water meters."

" Another meeting of the executive committee of this associa-
liLin took place at their offices, 41 Corporation Street, Manchester,
OIL March Slst, 1863, Wilham Fakbairn, Esq., in the chair.

"Ihiring the past month there have been examined 370 en-
LJ'ies — 1 specially; 492 hoilela — 6 specially, 17 internally, 60
iliriroughly, and 409 externally, in which the following defects
iiiive been found: — Fracture, 2 (1 dangerous); coTtmovi, Vft l^

I

I

I

»i ENGINEERING FACTS. [DfV. I.

dangerous); safety valves out of order, 4; water gauges ditto, 21
(1 dangerous); pressure gauges ditto,. 16; feed apparatus ditto,
d; blow-off cocks ditto, i7 (1 daugeroufi); fusible plugs ditto,
5; fiimaces out of shape, 3 (1 diingeroua) ; over-pressure, 2; de-
ficiency of water, 2; blistered plates, 2. Total, 130 (6 danger-
aaa). Boilers without glass water gauges, 1 ; without preasiiri*
gauges, 1 ; without blow-off cocks, 36 ; without bauk preasura
valves, 68.

EXK.OSIONS.

" It will be remembered that iu last month's report no detailed
particulars were giFen of No, 1 exploeion, which occurred to a
boOer not under the inspection of this association, and whichi
was of the double furnace internally fired class. Fartiaulus
have, however, been since obtained, and show that the exploei
was of a very simple character. It was the practice to keep up
a file in this boiler throughout the night for the purpose of
heating the mUI, and a boy was left in chaige to attend to it.
The demand made upon the boiler for steam was such thaf no
supply of water would cany it through the nighty and theiefora
it was the duty of the attendant to make up the dcficisuoy witlk
the donkey-pump. This, however, he neglected to do, in con-
sequence of which the furnace crowns were laid bare, the platsK
became red-hot, and collapse ensued. The boy was absent fcom-
the boiler at the time of the explosion, neither was any one elaa
near it, and thus happily no lives were lost nor any one injured^
while the dami^e to property was confined to that dona to the
boiler itself.

" This is just one of those cases in which a low-water safe^-
yalve would have been of service, nut only by its givii
alarm before the furnace crowns were laid bare, but also by-
Intting off the pressure of the steam.

"Twoesploaionshavoocourruddiiring the past month to boilers
not under the inspection of this association, by which 15 peraooa
were killed and 16 others injured, making a total of 31. Both
boilers have been personally examined subsequent to the explo-
fflon. The following is the monthly tabular statement;

IVjiLEBa] BOILER EXPLOSIONS. M 1

TABCTLAR aTATEMENT OF E-TPLOStOSS, 1
Pbov FiBHiTiBT Sin, 186-^, to Uabch 3Ttd, I8S3, noLrnr*. 1

■S"

Date.

Ponona
Killed.

Pinou

[njund.

~

No.*
Sa 5

Feb. 33
Mar. 17

Vertical IronwDrta Boapr.

intemslljr fired, .
OHiuar:; itouble liae or ' Un -

ouhiie,' inlerDall; fired.

1-S
2

1

-

^^K' " No. i explosion occurred at an ironwork to a boiler connected
^^^ a series of eighteen others. It wils very similar in general

fum&c« boilera, like which it stood erect, was of conaiderable
height, and surrounded with brickwork. They, however, are
heated by the flames paa^g off from the iron furnaces, which
play first upon the outside of the shell, then pass through open-
ings in the side into an internal descending flue, and escape to
the chimney; while the boiler in question had ita own indepen-
dent fiimaCQ pla<»d in the internal Sue, which was thus con
verteil from a deseending to an ascending one, the openings at
the aide hecoming outlets for the flame instead of inlets. The

in the ordinary ftirnace claae, both ends are hemispherical, which
is an important difference.

"The boiler was 30 feet high, and about 9 feet G in. diameter.
The internal fire-box was 10 feet high, 4 feet 6 in. diameter at
the crown, and also for about the first 3 feet 6 in. below ; from
which point it tapered outwards to a diameter, at the bottom, of
6 feet 6 in., leaving .in annular water space aU round, about 18
inches in width between it and the shell This fire-box was
united to the shell at the bottom by a flat plate connected by
rin^ of angle iron inside the water space. The crown of this
internal tire-boic w^ slightly domed, and flanged at its attach-
ment to the cylindrical sides, being amply stiffened by six angle
irons laid across and well riveted to it. At the upper part of
the fire-hoK were the two outlets previously referred to, and
which were formed by short transverse flues passing through the
water apace, and thus establishing a communication between the
iuteiwl iiua-w aud the eiLtexaal Hue. Tiwae a^uA &.&«&, ■«\flRXs.

ENGINEEKINQ FACTS. [Div

were oppoaite one to tlio other, and at right angles to tlio fnruaca
door, were 2 fe«t 6 in. in diameter, and attached bj rings of
angle iron at each end

" The thickness of the plates waa ; in the hemispherical end
and cylindrical sidea of the external shell, ^ in. : in the. flat
plate at the bottom of the water space, 7-16th in. : while all tha.
angle irons ware 3 in. by 3 in. and ^ in. thick. In the fire-box
the thickness of the crown plate was 4 in-j and that of the aides

17-1 6th in.
"With regard to the lay of the plates, that in the shell was
according to the usual plan, being jadial in the hemispherical
end, and circumferential in the cylindrical sides, the a
the latter hroaking joint; while in the taper portion of the fira-
box the plates were laid longitmlinally, and thus, which it ia
important to notice, the seams were in line for a length of be-
tween 6 feet and 7 feet. The riveting was single tlirongliout,.
and the seams were the ordinary overlap.
" The boiler had been fitted with a float, two gauge tape, o
feed stop valve, one feed back-preasure valve, and one lever Bofety
valve of 5 in. diameter, which was loaded to a pressure of nearly
50 lb., and at all events would have allowed the steam to have
reached that pressure when blowing olF freely. Also there v
two junction valves, one of which was in the steam pipe oi
municating with tbc entire series of boilers, and the other in that
connected to the steam hammer. There was no steam pressnm

» gauge on the boiler itself hut one was fixed to the main steam
pipe beyond the junction valve, and thus afforded no indiealion
of the pressure of the ateam within the boiler when it was shat
off from the others in the series. Both of the junction valves
were closed at the time of the explosion, and thus the aafet|y
valve formed the only outlet for the steam. What the pressure
then rose to cannot now be ascertained, the steam pressure gaug^,
as just pointed oat, giving no indication under such c'
stances. The aafety-valve, however, was found to be free after
the explosion, and there ia no reason to conclnde that it had been
otherwise previously. But it is apparent from this how ciraum-
fliances will arise which make it important that every boiler
xhf^uJd be fitted with a duplicate safety-valve, as well as with ifai
^^dependent pressure gauge.

F

CAUSES OF EXPLOSION. 37

A Tety general impreaaion exists tliat tlie cause of most, if
not of all, the explosioua that occur at ironworks, is to bo found
in the old age and dilapidated condition of the loilera: such,
liowever, was not the case in this instance : the workmanship of
tlie boiler wad eatisfactoiy throughout, and its condition good.
It was reported to have been at worlt only a few months, winch
its appearance corroborated. Were all boilers in as goiid a con-
dition as this one waa, explosions would be of much rarer occur
rence than at present.

" The cause of this explosion was clearly not ' shnrtness of
water;' the crown of the fire-box was uninjured, the colour of
the plate black, a thin scale covering portions of it, wliile the
rents made in the boiler were not those which a deficiency of
water would have occasioned.

" A serious oversight had been made in the design of the
boiler, the top end being hemispherical and tlje bottom flat.
The bemisplierioal end would, when the steam was fully up and
blowing off freely, have an upward pressure of nearly 350 tons
acting upon it and tending to teat it away from the bottom.
There would be an equal downwdrd strain counteracting this,
induced by the pressure of tlie steam upon the crown and taper-
ing sides of the fire-box, combined with that upon the flat plate
lurming the bottom of the annular water space. As long as the
itiacliment between the bottom and the top of the boiler held
Liud, the two forces would be in equiiibrio, and the boiler m-
luain at rest upon its bed. But should the attachment fail, the
upward force would instantly alioot the top of the boiler up into
ihe air with a buoyancy of 250 tons, which, it may be remarked,
i.s equal to the weight of a long raUway tram, including the en-
L-ine and tender fully equipped with coke and water. This ac-
I iipu is exactly what took place. The flat plate at the bottom
jive way, rending eorapletely round thi-ough the seam of rivets,
lit the outside ring of angle iron which attached it to the elieU ;
when the boiler flew up and wag carried to a distance of 160
yards from its original seat. The brickwork at the top of the
chimney was shaken, and there were marks'of violence on the crown
(if the boiler, so that it is possible that it struck the top of the
•■iiioiney in its course, Tliera is nothing surprising in this when
tUs aui^i'it of tlie pent-up force of steam within bo \aige a.\; "

I

}g ENG1K.F.F,R1N0 FACTS. fDii

is Gonaiiiared, and the iliie appreciation of which ahowa how m
oeaaary is the suppoaition of the existence of explosive gaseoua
ompounds, or any force greater than that of the ateam itself j
while the propagation of such theories only tends to divert atten-
tion from the real cause of steam boiler explosions. The rcait
the fiat bottom plate, however, waa by no means the only o
that was maile. Tlie short triuiaverse tinea passing through the
water space, and which considerably assisted the bottom platof
also gave way and were torn from both the shell and fire- box,
their rande of fractare giving unmiatakable evidence of the up-
ward flight of the shell The resistance of these fines to fracture
had severed the fire-box in the waist at the ring seam of rivet^
at which the longitudinal plating terminated : and thus the fire-
box crown, ae well aa one ring of plates with the two abort iva
tubes, had flown up together with the shell, which made a eoe
what remarkable and complicated featuw ia the development
the rents. Added to this the remaining portion of the fire-box,
which waa taper, and plated longitudinally, rent at one of the
longitudinal seams opposite the fire-door, and collapsed at that

" Some difference of opinion has existed among the engineers
who have examined the boiler, aa to whether the exploait
ginated at the rent of the flat bottom plate, or at the collapse of
the fire-box. Though there may be some difficulty in detei
ing which was the weaker spot of the two, there has been noma
in deciding that the boUer was inherently defective; and the
opinion has been unaniinons that there is no evidence for attri-
buting the explosion either to ' shortness of water ' or to
eive pressure, but that it was clearly owing to the mal-consteuc-
tion of the boiler itself It may be added that the t^iplicatioii
of the hydraulic test would have detected and exposed the weak-
ness both of the fire-box and bottom flat plate, the former by ita
temporary flattening, the kttet by the moving and rising of the
outer shell.

" The jury at the coroner's inquest came to the following c
elusions, which are quite ia accordance with the preceding
port; — 'That the explosion was caused by the bad conatruotion
0/ ibe boiler. That every boiler ought to be supplied with
ateam preasam gAtige, and that no daw WV^ ou^I. Sa \ti ^^ -

work before it lias been examined by aonio competent eugitieer
«nr) pronounced to be eafe.'

'' No. 5 explosion occurred to one of two mill hojlerfl working
si'le by side and connected tngetlier, botb being of the plain
^doable fined iDterDally fired dass, termed ' lancaaliire.'
^^E^Tbe Imgth of the one in question mb& 28ft., tKe diameter of
^^Kehell lOft., and tbat of the fines, which were parallel through-
^^Ht their whole lenfiflb, 3ft, 9in. ; the thickness of the pktos
^^rere aeven-sisteentlis in tbe Bhell, and lliree- eighths in the flu<*.
The boiler hiid been fitted with one glass water gauge, one feed
back-pressure and riiop vaive combined, one blow out tap, one
lever safety valve, and one Schaeifer steam preBSiire gauge, com-
mon to both boilers. The pressure at which the safety valvfl
waa slated by the engine attendant to have blown off, was 301b.
on the square inch, which an examination of i.tB dimensions,
lever, and weights corroborated.

" On examining the boiler it waa found that the right-hand
flue had collapsed from one end to the other, and by the flatten-
ing action had become severed completely in two at some of the
ring seams of rivets, as well as torn away from t!ie end plate at
the back of the boiler. The boiler bad not stirred from its ori-
ginal position, and the connections to the one alongside remained
unbroken.

" The rush of water, however, from the opening at the back
had blown up tbe bricfe flue and carried away the end wall of
the boiler house, in consequence of which a floor above, as well
as some cast iron girders by which it had been supported, were
brought down. It was by the fall of the building that the three
men re{*ived their injuries, one of whom was found to be dead
when dug out of tbe debrit. At the front end of the boiler the
furnace mountings bad been blown o£E

" The amount of damage done to the surrounding property was
comparatively inconsiderable, and this is generally found to be
tU.i case where explosion is confined to collapse of the internal
'liiea. Where, however, the external shell gives way, the conse-
■ liii>noe8 are much more serious. The boiler does not then re-
main quietly in its seat as it did in the present instance, but —
III tbe effect of the percussive action of tbe steam, which was the
only element of injury in this case — adds that of the fivj^vt al i

I
I

ENGIHEERINO PACTS. [Bn

' fraginenta of the shell, as in the preceding No. 4 es]ilosi
aa well as in the one that occurred to an. ironworks boiler ia
December last, the particulars of which were given in the report
fur that month.

" With regard to the cause of the collapse, there was no evi-
dence of 'ehbrtnesa of water,' judging from the appearance erf'
the plates : added to whiuh, the other fai'uace in same boiler re-
mained unaltered in shape, which could not hare been the
hail defieienuy of water occurred : while, in addition, it appewrod
that the oollapBe of the flue had commenced at the middle of ita
length, and iii}t over the furnace, where the shape was lese dis-
torted than at any other part.

"The collapse cannot he fairly attributed to 'ahortneae of
water,' but ita true cause will be fuund in the construction
flue, which waa not atrengthened with flanged aeama or the ad-
dition of any hoope. Such a flue as the present, of so la^ a
diameter as 3ft. 9in., and 28ft. long, made of plate only three-
eighths thick, is not sate for regular work with steam at a preB'-
eure of 30 lb. per square inch, as was the case in this instance.
It might work for a time, but still there would be a risk, as the
event proves ; a mk that might have been avoided had the floe
"been strengthened with any of the approved methods, namdy,
flanged seams, or hoops, either of angle iron, T iron, bridge r^
section, or any otbev suitable form ; to the importance of adopt-
ing which attention has been called, it is feared with tedious
frequency, though an apology for so doing it is thonght may be
found in the repeated occurrence of such explosions as the pre-
sent, and in the loss of life consequent upon them.

" It may here be added, there is every reason to conclude that
the boiler in question was an illustration of the danger referred
to in previous reports, arising from internal flues being actually
oval, although supposed to he circalar. The angle iron rings at
the end plates were circular, hut the inclination of the
tlie collapse of the flue indicated that the middle portion had
been ovaL The other flue alongside was evidently so, and ha4
in consequence been strengthened by two stays attached to the
crown. Tlie flues of all the boilers under the inspection of the
afls<)ciation are gauged to ascertain their actual shape, when tlie
Btfuihezs aUovf an opportunity of miikiug ' thorough esamiiiar

Boirm.i BOTLaH EXPtOSTOIT-S. 11

tioua,' without whith it cannot be doue ; and very numerous ara
fliB instances in wliioh fluea, previously sujipoeed to be circular,
:in! fiiund on actual nieasinement to be oval.

" This explosion is one tliat must be added to the category of
those caused by mal-eonstruction of the boiler, and camiot be
termed accidental. The application of the hydraulic test would
have detected the weaknesa, and the adoption of any of the ap-
proved methods of strength ening flues mentioned above pre-
vented the explosion. These preventive* have now become com-
mon knowledge, they can be applied at little eiponBe and by any
iipiinarilycompetent boiler maker, and thus are within the reach of
alL It may therefore be fairly pointed out that their rejeution by
I >ne manufacturer is an act of injustice to others, since nothing can
operate more directly to induce Government interference with
l.lie present unfettered use of eteam. than the frequent occurrence
of ifiss of life, through the neglect of precautions so simple as
those just aUaded to."

At the last ordinary monthly meeting of the Executive Com-
mittee of this Association, held at the offices, i\ Corporation-
Street, Mancheater, on Tuesday, May 26th, 1863, Mr. L E.
Jletchor, ciiief engineer, presented his Monthly Report, of which
the following is an abstract ; —

" During the past month, there have been examined 257 en-
giuea — 1 specially; 420 boilers — 10 specially, 11 internally, 77
tlioronghly, and 322 externally, in adiUtiou to which one of
these boilers has been tested by hydraulic pressure. The follow-
iii£t defects have been found in the boilers examined; — Fracture,
.-, (3 dangerous); corrosion, 22; safety-valves out of order, 1;
\*"iiter gauges ditto, 11 ; pressure gauges ditto, 6 ; feed apparatus
lil.to, 2; blow-out apparatus ditto, 3 ; 'fusible plugs ditto, 1;
liiruaces out of shape, 2 (1 dangerous); over pressure, 2 (both
ikngerous) ; blistered plates, 2 (I dangerous); total, 60 (7 dan-
Suttiua). Boilera without glass water gauges, 2 ; without pressure
i-'iugea, 5; without blow-out apparatus, 17; without back prea-
nure valves, 34.
" The occurrence of explosions during the past few months
3 ii'equeiit, that the reports of their details have pre-
i any notice of the defects found to exist in the boilers
jit iBSpection, further than tliut ^iveu in the monthly liots as

KNGINEKKINfl FACTS. [Dn

above ; and, therefore, the present opportunity may be take
for some slight araplilication.

" Serioua cases of corTosion contiiiiie to be met with at the
bottom of those boilers wiiich are set upon brick mid-feathen^
tunning underneath them from one end to the other along t"
centre or kee! line. In this mode of Betting, any water wki
may fall upon the boiler, or leak from the Beams, triokleB dowl
the shell, and settles on the top of the mid-featliei
with the plates. Also where damp exists in the flues, it easily
rises through the mid-feather and reaches the boiler. Conofdoi
may be going on along the centre of the mid-feather and not b

»viaible at the sides, and thus pass undet«cted even on careful ex-
amination—several instances of whiuh have recently been met with.,
" In one case, a boiler, 10 ft, S in, in diameter, aiid of platev
7-1 6tbs thick, was found, upon the removal of the brickwork, to be
deeply channelled for a width of 6 in. along the bottom at tht
centre of the seating, ho incJioation of which was given at t'
aides of the wall, nor was it detected by hammering int^rnalljfj
but remained unknown until the removal of the brickwork,
another boiler, tlie shell of which was 8 ft. 2 in. diameter, a
I in. thickness, the plates were found to be channelled longttii-
dinaUy along the centre of the mid-feather for a width of 8 in.
The seating was 15 in. wide, and the chancel died out at 3 i
from the outside, thus giving no external sign. In a third Ixaler,
the flues of which were damp, the whole of the plates in contact
with the mid-featiier were found to be corroded and as much i
a quarter of an inch in thickness eaten sway. Other instonees
might be adduced, hut the character of the injury is so aisulsz
in each case that it would be tedious. Those already given will
show the grounds upon which the following recommendationa

" I. Wherever it ia practicable to do so, dispense with, mid-
feathers altogether, and substitute what are termed two side walla
for them, 2. In those cases where the small size of the boilei;
forbids this, make the bearing surface of the mid-feather wall a«
narrow as possible. 3. Any that must be retained in use, should,
in preparation for annual ' thorough ' inspection, be removed — at
least where in contact with the transverse seams of rivets — "
order Co admit of complete txaminaUun,

OOBKOSION" OF PI.ATEP, 43

" Further amee of corraBioD juaj be niunttouuil oocQrriug to

r boilers tfaao Iboae set upon mid-foathsrs.
" A tabular boiler, without any external fluea, van fuiind no
aoplj channelleti at the bottom of the shell at tlie tnuisvt-'Die
3 of rivets, that the pLitt«s were reduced to the tinckneas of
a abeet of papvr, and a hole knocked thmugli Ihcni in sounding
tlwir strength with a hammer. A seoond b«ler, of ordinury
double furnace, intemallj' fired construction, was ao eaten away
hf corrosion at the first bottom plate from the ironti that, m in
the preoeding case, a hole was made on examinutiun; the corru'
siun being due to leakage from the glass water guages, and mud-
bole joint, as well as to the practice of Blocking the afihes while
lying at the &ont of the boiler. In another case, where thi^
cross wall below the front end of the boiler was as much as two
feet in thicknees, the plates wore corroded nearly through. So
great a thickness aa 2 ft for these walls is quite unnecessary, as
well as objectionable, and it is recommended that they should bo
removed periodically for the examination of the plates.

" Several casee have been met with during the past month of
injury occurring to externally -tired boilers at the parts imme-
diately over the fnmaee, the plates bulging, cracking at the rivet
^^^lea, and the seams straining and leaking. One of our mem-
^^Kn has contributed a sample plate cut out from a boilfr of this
^^^Bbb, which is bulged down at the sohd, and cracked completely
^^H^tigh, although the boiler was amply supplied with water;
^Tais plate is a fair sample of the danger of the extern ally-fircd
class, and lies at the office for the inspection of membets,

" A Eafety-valve, the spindle of which passed through a bushed
h i>te in the cover, was found to fit so tight as to be quite fast
^ig huah had been fitted to prevent the inconvenience arising
I the escape of steam, under the impression that a safety
ive was nnneceseary, as long as the boiler was provided with a

a. pressure gauge.
*' HxploeioM. — A report relative to Explosion No. 9, recorded
■ tha last month's abstract, has since been received from an eii-
r who examined the boiler shortly after the explosion had
kcurted, and from which it appears that the boiler, which was
p plain cyL'ndrica! egg-ended construction, and externally-fired,
o ooustantly {oaal to bs the vjdSA io. X'E^ <^UU!%

I

I

I

ENGIHEERING FACTS. [Drv. I.

■at tbe transYorao seama over the fire, the shell dividing into
two parts, which were thrown souib distance asunder. Oua
laoiler only, and which was not imder the inspection of this
Booiation, has been repotted to have exploded during the last
month; the explosion oountruig at too great a distance from
Manchester to admit of a personal investigation. Should any
particulars of interest be ascertained, they will be communicated
in the next monthly report. — Tlie explosion will rank as So. 10
in this year's list."

At the last ordinary monthly meeting of the Executive Com-
mittee of this Association, held at the offices, 41 Corporati
street, Manchester, on Tuesday, June 30th, 1863, Mr. L. E.
Fletcher, chief engineer, presented his Monthly Eeport, of which
the following is an abstract :—

" During the past month there have Ijeen examined 340 en-
gioea — 2 specially; 528 boilers — 10 specially, 12 internally,-
104 thoroughly, and i02 externally, in which tlie foUowii^ d&-
fecta have been found : — Fracture, 8 {2 dangerous) ; coiroKon,
3i {3 dangerous); safety-valves out of onler, 9 ; water gaoge
ditto, 31; pressure gauges ditto, 9; feed apparatus ditto, 2.
blow-out apparatus ditto 36; fusible plugs ditto, 13; fumacea
out of shape, 4 (2 dangerous); over pressure, 2 (both danger-
ous); blistered plates, 3; total, 140 (9 dangerous); hoilejs withr
out water gauges, 8; without pressure-gauges, 8; without blow-
out apparatus, 13; without back ]>reesure valves, 39

EXPLOSIONS.

"So. 10 Explosion — The fact of this explosion having owunred
was stated in last month's report, but no detailed particulars had
then been received. It has since been ascertained that the boiler
was a plain cylindrical egg-ended one, estemaUj lired, and that
the explosion was caused by rents commencing at the seams over
the furnace, which baa so frequently been found to he the
in this class of boiler, and caUed attention to in these reports.
Two other explosions of a very similar character have happened
during this month, particulars of which are given.

" Nine explosions have occurred during the last month, by
whiiih eleven persons have beenTdlled, and twenty-one othem

TABLE OF EXPLOSIONS. *5

i-tf the flue, and by which ao injury waa done either io pereoiis
■ ^ smroumliiig property, occurred to a boiler under the itispectian
; this aasociatioa; while in the eight remaining cases not nne
■ f the Tioilors was under its care. Details will be fuuud below.
The following is the monthly tabular statement: —

TABITLAR STATEMENT OF EXPLOSIONS
Fhoh Uii 23d, ]Sd3, TO Jem SGia, 1

Progres-
riveKo.

foiises.

Dale.

General Desoription of
Boiler.

11

£'.5

1

So. n

So. 12
No. 13
Ko. H
Ko. IB
So. 16
No. 17
So. Ij
No. I!'

May 29

fSX

JuM 13
Joneia
June H
June 15
June JG
Jnne 26

Cjliudrioil eM-«nded, eirtenially fired.

ITgirigbl funuwe, uKeroallv fired, .

Details DOt jet ■scortuiicd.
fOrdinuT single floe, or 'Cornish')
1 inteniollj fired, . . . f

Cylindrical ega-endEd, BxtenuUlj fired,

Marine, ...'...
Details not yet aaoertained,

Total

1
B

1

a

1

1

12

(1
G

3

2
17

S

1

6

1

11

21

32

"No. 11 explosion occurred to the boiler of i locomotive en-
ifiiie whUe r unni ng with a passenger train. Between fifty aiiil
sixty perBons were injured and four killed. This result was ni't
' K^casioned however by the explosion only, but principally by the
train" running off the line. Whether the engine lenying the
mils was the cause or the effect of the explosion is an interesting
question, and one now undergoing strict investigation. All the
facts likely to prove of value to steam users generally, which
may be elicited with regard to this explosion, will be given to
the member* of the association at the earliest opportimity after
the close of the inquiry. The only injuries directly attributable
t I the explosion are those which happened to the engine-driver
.ml fireman, both of whom were severely scalded, the latter hav-
ii^ died in consequence.

'• No. 1 2 explosion, from which five persona were killed and
twelve others injured, took place at an ironworks. Tlie boiler
in question, which was not under the care of this association,
"f anainiaed ahactdy afW the exploBUia. W'^'^^sofi^i

46 EKGIBEEKING FACTS. [Div.

aud found to be of cylindrical egj-ended ooHBtruetion, having a
internal flue of hoise-shoe sliape, botli the inlet and outlet Q
which, pnsaed throngh the further end of the hoiler, the n
of the ilue being quite independent of the shell, aud thus not
forming any longitudinal tie from &ont to bode The hoila
was extern^U^f iired, the flame first passing underneath the abel^
aud then entering the flue at one leg of the horae-ahoo, a
escaping to the chimney through the other. The length of the
ehell was 28 feet, the diameter 8 feet 6 in., and the thickneBS a
the plates seven sixteen the, while the blowing-off waa abool
40 lbs.

"The boiler had rent completely into two parts at the foorttl
tranaveiae seam from the front end, the lai^ei portion of the ^ell
flying forwards in a straight line from its seat, turning a anm-
mersault in its course, and landing in a position quite t
of its original one ; the egg-end pointing to the brickwork seating
and the open one from it. The smaller portion had floi
much greater distance than the other, and not^ as is usually the
vaae, in. a direction immediately opposite, hut at riglit angles
it. A sister boiler working alongaide, and connected to the o
in question, was moved laterally, Bufiieiently so to disturb t
brickwork seating and break tlie steam pipes, though not to i
seat it altogether.

" With regard to the cause of the explosion. The boiler i
fifteen years old, the plates over the furnace had already 1
repaired, and it was stated that the seams at that port had 1
observed to he leaking only a quarter of an hour before the oat-
plosion took place; while, in addition, tlie shell waa found to be
patched in several places, and the plates cracked from the rivefc
holes to the edge. It is conclwled therefore, on considentioiB
of all the circumstances, that the boiler could not have been i
good condition, the correctness of which it is thought d
some corroboratioa from the fact, that the hoiler alongaida
futmd at the time of making this examination to be also leaking
at the seams over the furnace, and that considerably, although
not under pressure. An examination of the fractures, as well aa
a consideration of the direction in wliich the parts had flown,,
led to the conclusion that the rent had commenced at a "
tiuia/ geain of riveta, extending for some \.w() m t\\tw ^lataa o

BoiLBBS.] DE8CniPT10K OF EXPLODED BOILERS. *T

tbe faniace. The rent ran along aa iar ae tliis longitadinal scam
extended, and when met by a plate crossing it oi ' breaking
joint,' as it is termed, then developed into a transverse rent, and
completely severed the shell in two. It is thought that t)ie fiict
of this lon^tudinal rent in the furnace end of the shell, being
situated on one side of the centre or 'keel line,' aceoimta for
that portion having been hlu^vn laterally, and that the iipwapl
direction which it had evidently taken had causeil the summer-
sault of the remaining and larger portion. The explosion, there-
fore, is attributed to the imperfect condition of the boiler; and
althoDgh such defects would not be dangerous in a anitably-con-
structed, donble-flueJ, or 'Lancashire' boiler, which is always
internally flred, they are generally found to be fatal in those
boilers which are fired externally; while in the present case the
effect waa aggravated by the feet of the seams of rivets over tlie
tire being in line, and the diameter of the shell being as much
as 8 feet 6 in.

"No. 13 explosion, by which no one wa.i injured, or the sur-

miinding property dama^^, occurred to a boiler under the inspec-

n o( this association, the particulars of which are as follow; —

■ The boiler was an upright fumaoo one, working in connection

■. ith two others of similar construction to itself. It was heated

hy the flames passing oif from a furnace employed in preparing

heavy forgings; the Hames passing through an internal tube in

the eentre of the boiler, which ran directly from the top to the

bottom. The extreme height of this internal flue was 26 feet

2 in., but it was not of one diameter throughout. In order to

admit of a brickwork lining, to guard the fliie above water line

the upper part was made of a larger diameter tjian the remainder,

and attached to it by a flanged plate which formed a 'set-off' or

ahel{ on which the brickwork rested ; again, the lower portion

of the tube had a bell-mouth at the bottom, to afford an etisy

entrance for the flame. The length of the upper part was 11

■ 't 4 in,, and the diameter 3 ft. 3 in. ; the length of the inter-

. ■Hate portion waa 10 feet 4 in,, and the diameter 2 feet 6 in.j

i.ile the length of the bell-ntonth, waa 4 feet 6 in., and tho

■ meter, at the base, 3 feet, the thickness of the plates being

( '.'e-eightha of an inch throughout, and the blowing-olf pressure

■-■ Iba.

48 ENOINEEKIKG FACTS. [Div, f

" Iho explosion, which did not iii auy way dishivb tho ori'
ginal positioa of the boiler, resulted from collapse of the ii
fiue tu.be, the collapse being conlined to the isteriaediate portion
just deaciibed, which it rent at about the middle of its length,

"A tube of such small dime usioua as those just given, namelj^
Only 10 feet 6 in. in length, and S feet 6 in. in diameter, i
of plate three-eighths in thickneaa, if of good material and v
inanship as this one was, would be amply Bulficient for a preasurB
of 56 lbs, if working under ordinary circonostanoea. It has been
BJnee ascertained that tiiia flue baa been reconstrncted of pIftteS
of precisely the same thickness as the old one, and that, c
mitting it to the hydraulic test, it was found to sustain a pressure
of 120 lbs. per square iuch without yielding in the slightest d&
gree, although carefully gauged. This clearly shows that the S
did not collapse from the weakness of its original construction.
This would suggest the conclusion that the water supply had
been allowed to run short, hut no positive indications of th*
plates having been overheated appeared upon examination, thoi^h
this may, however, have taken place on previous occasions with-
out its being known. On account of the height of these uprighl
furnace boilers, the glass gauges hccome inaccessible, and the o
in question was fitted with two gauge taps only, carried down
by means of syphon pipes to within reach from the floor. Ihtu

the water could sink below the proper level witliout offordJi M

any external indication, and would consequently pass uuknovD
should the gauge taps be neglected. This may have happen
without any immediate collapse of the tube taking place, althongli
the flue would be materially weakened by it, and rendered li " "
to give way eome time after in consequence. It is impossible ta
say whether the flue tube n'as getting out of shape or not, sin
the boiler had been in such constant work that no opportunity w
afforded the association of making an 'internal' and 'thorough*
examination for upwards of three years. This may not thereforo
he an improper time for calling attention to the importance
generally, of having spare boilers, so that a suitable opportunity
may be a&brded for examination, as well as for cleaning and'
repair. The boiler was found to be heavily incrusted with hanl
scale, which must considerably have tended to the overheating
and weakening of the flue, to wMo^i tttcso \ertical boilers s

mm

alwayB prone, from the tendency of the ascending sttiiui tu cliiiij
aii'und the tube and prevent the contact of tlie water. The
inaccessibility of the gauges and tittings of these vertical boilers,
<jii account of their height, is another disadvantage connected
with them, and indeed h thoroughly good and safe furnace boiler
must still be considered as a deHideratum.

" No. 16 expiosioii happened at an iioiiwnrka, tfi an estemally-
iired boiler, 40 feet long, 8 feet in diameter, made of plates
seven sixteenths of ati inch thick. The shell of the boiler gave
way innnediately over the furnace, the fireman being acaliled to
diath from the strearu of hot water iaaning from the rent. Tiie
boiler had been repaired at thia part, by putting on a new plate,
two months previous to the explosion; and it was at this plate
that the rent occurred.

" This boiler, which was not under the charge of tliis associa-
tion, was not personally examined ou the occurrence of the ex-
[doeion, but an engineer who inspected it shortly after baa kindly
fni-uished the following particulars: — The plate ripped open
ibrougb the solid metal in two place.°, the rent being about 15
in. long and 1 in. wifie; wiiiie the parte surrounding it were a
good deal cracked, and the seams patched, so that the bottom of
the boiler was evidently in a very defective state. The ruptured
plate was about aeven-sixteentha of an inch tldck, and did not
appear of very good quality, as if not thoroughly welded in roll-
ing; but the fracturea were not, properly speaking, 'blisters,'
since the whole thickness of the plate had come down at once.
In adtlition to the inferior character of the plate, the boiler was
heavily coated with incrustation, and this bad accumulated at
t)ie bottom for a depth of 3 inches just over the fracture, and
extended for a space of 4 ft. by 2 ft. Thia mud had hardened
BO much that tbe water and steam, ploughed but a small hole
through it in rushing out There can be little question that this
rnftling of mud had kept the water away from the plate, anil thus
' il to its becoming overlieated, iiom which it gave way. There

- plenty of water in the boiler at the time of the rupture.

" It will be clear that it is scarcely possible for such a cake of
■ liinent to iiave formed upon the furnace crown of an intoTOaiVj

T'll boiler, and also tljat an efficient blowing-out appaiaWa ■^o'iii

<vs pKvaaCed ibe aoeatnulation in a great measure, i£ no^- oXX.«-

ENGINEERING FACTS.

[Div

I
I

gBther, and tliua that the explosion waa due to the dangeroutf
character comiuoii to all exteroally-iirad boileis, coupleil in thii
use with neglect.

At another meeting of this asaociation the report for the montJl
of July was presented by the chief engineer, of which the follov

; is an abstract: —

"During the past mouth there have been exaniined 324 en-
gines and 450 boilers. Of the latter, 17 haye been t
speeially, 11 internally, 55 thoroughly, and 367 esternally, ill
addition to which 3 of these boilers have been tested by bydranlid
pri»Eaure. The following defects have been tbund in the boilert
examined ;^Fracture, 8 {2 dangerous); corrosion, 1ft; safety
TalvBS out of order, 9 {2 daugeruos); water gauges ditto, 21:
iges ditto, 8; blow-out apparatus ditto, 37; fusibl)
I ditto, 2; fnrnaces out of shape, 4; over pressure, 1 (dan
geroue); deficiency of water, 1 (dangoroua) ; blistered plat^ 3,
total, 110 (6 dangerous). Boilers without glass water guages, 2;
without blow-out taps, 38; without baek-pressui'e valvea, 41.

i gratifying to find that the number of ' thorough' ez
niinatioua of boilers, though not Idgh during the paat month, ii
steadily increasing. X)uriug the month ending June 36th ti
as many aa 104 were made, in addition to 12 'internal' and 1<
'special,' — -making 120, independently of the ordinary 'external
examinations. This number is a greater one than has 1
reached in any previous muiitli.

EXPLOaiOKS.

" One explosion has occurred dining the lost montlt, of a very
fatal cliaracter, particulars of which are given below. The fol-
lowing is the monthly tubular statement

TABULAR STATE BEST O

Froh Jubh 2Tth, 1363, td Jult 21th, 1303, e

mXK».'! DESCRIPTIUN OF EXPLODKD BOILEltS. fil

No. 20 explosion, bj* whicb ten peraous were killed nini four
irtliers injured, occurred to an ordinary mill boUer nf the two-fluiui
' Laneashire' class. This boiler was not under the inspection o(
1 1] is aaeociatioQ.

"The dimensions were as follow: — Length, 30 feet, diamet<?r
t'f the aheli nearly 7 ieet fi inches, and that of the funiace tu)ie3
— ^which were paraUel thronghout, and not slrengthenwi by any
li'iopa or flanges — 2 feet 8 inches; the thickness of the plates in
tlie shell and tubes, seveii-sizteenths, in the Bat end plates half
nil inch, eaeh of them being strengthened witli three gu>)s«t atAV^,
.secured with double angle irons.

" The longitudinal seams in the shell were not laid in line, but
disposed so as to break joint. The age of the boiler was aliout
two yeara. It had not been tested by hydraulic pressure,

" The boiler had been fitted with a single lever safety-valye,
the valve being incloaed in a liox bonnetted over fiwm which the
waste etwim escaped through a discharge pipe, carried through
the wall of the boiler house. It hail also been fitted with a glass
iriiter gauge — a fe«d-oheck and back-preasure valve conibinuil,
rl icd to the front end plate, a little below water level — a blow-
iit or mud tap, and a steam pressure gauge, of the dial class;
the^iler had no tap for fixing an indicator, so as to check
accuracy of the gauge, and ascertain the actual working pres-
with the steam up.

The boiler was rent into so many fragments by the explo-
thut it was completely destroyed, while considerable damage
was also done to the surrounding property. Both the furnace
tubes were torn away Ironi the end plates, as well as separaterl
into two pieces, dividing at one of the transverse seams at the
middle of theic length. Three of these lengths, weighing up-
wards of a ton each, were blown over a row of cottages, one
alighting on the first floor of a dwelling beyond, having broken
the roof in its fall, the other two lengths falling at iii-
ite distances between these two row of buildings; while
fonrtfa ilew in a direction neai'ly at right angles with the
and also fell upon a cottage carrying in the root The
e weight, which was a ball of ab'int 8 inches diameter,
pward't, and, on its fall, broke through the roof of a
The shell of the boiler hsid beeu lotiv w^ "\vi\a so

I

I

■ 52 ENOIKEEBmG FACTS. [Dlv. I,

many amall pieces tliat it was diflicult to trace tlie course of tlie
rents, and to determine where they had first com me need ; but il
may be remarked that one of them ran through the manhole,
which waa not atrengtlieaeil as it should have been by a. sah-
atantial mouthpiece. These fragments of the shell had not tldwn
so far as the fiue tubes liad done, but many of them lay scatteredi
near the original seat of the boiler, while some were buried under
the ruins. The end wall of the intll was blown down, and the
various floors laid open, while the eng;ine waa completely bulled,
in the debris. The chimney was gashed by a large rent, running
up it for half its height, and stood tottering over the old seat of
the boiler, so that approach was dangerous j while the ground
surrounding was covered with bricks, and the ruins of the
jured buildings; the windows in every direction, a^ well as many
of the roofs, being riddled. But it is dil^cult to convey an ade~
qunte ideit of the ruin that had been produced.

" The cause of the explosion has twice been investigated before
a coroner's jury, conducted in each instance by a difiurent ooi
on account of the localities in whicli the deaths occurred,
entific evidence waa given in each case. At the first trial, one
scientific witness gave it as his opinion that there were no tracw
of there having been an^ deficiency of water, hut that the aafe^-
valve had been derange 1 and inoperative; while at the seoond
trial, another scientific iMtness thought that the aafety-valve bad
worked quite 'glibly aiii that ahirtneaa of water had caused
the explosion, A verdict of accidental death was brought
each inetance,

" With regard to the explosion having arisen from shortness of
water, it was given in evidence at the inquest that the ^
glass was blown llirough, and plenty of water observed shortly
belore the explosion happened: the correctness of which
borne out by subsequent examination, since the flues were fonnd
to be coated with incrustation, which over-heating, had it occurred,
would have disturbed; while, in addition, the furnace crowns
could not have retained their shape as they did, had the water
been low,

" As to the explosion being due to excessive pressure consoqaent
apon the defect of the safety valve, it is true that the spindle of
ibe rah'e waa bent, but it is a matter of o]^inion whether thf

CAUSES OF BOILER KXrU'SIOSS

did not become so subsequently to the esplosi^'n,
i^oiiEGqueiicc rather than ita cause. At the time of making iny
own examination, which was done immediately on the wtplosiou
being reported, there was no opportunity cif seeing the a»fity
valve, since it was in the hands of the jury who were then ni-
gaged upon the inqueat; but I am informed, an good BHthorily,
that the injury was snch as could not have ncciirred to the vnlve
m regular work, while it was kuuwn to have been previnusly in
gi>od ortler.

" But, apart from the condition of the safety valve there are
other considerations afl'ecting the view that the exploBion was
due to excessive preaatire alone. There was no evidence to pwjve
that the pressure exceeded 60 lb. per square inch, and neithf^r
that nor twice the aniount would have rent the shell had the
material and workmanship been good; while from the feet that
the flue tabes wore not collapsed, nnd the shell was rent into
fragments — although the latter should have resisted twice the
litrain of the former — it is clear that the explosion did not result
from tdmple over iiressur*.

" It cannot be douhtid that the plates were of very bad
, ijtiality, one of them in the shell, situated at the top of the ex-
tTnal flue, had fractured through the solid when the boiler was
at work a few months since, while it is reported that one of the
ticieutific witnesses, who gave evidence at the inquest, stated thiit
merely with the blow of a brick he had broken off a piece of
]>Ute about 15 or 16 square inches in ai'ea, and seven-sixteenths
iji thickness. Also, another engineer, who had an opportunity
of fully examining the plates after the inquest was closed, has
med me that he found them to be very inferior, while a
a kindly forwarded to me, at my request, by the owner
(the boiler, shows a short and cryetalhne fracture, is Uttie hett.pr
I, and quite unfit for use. The oaat-iron nature of
the plat«s rendered them less adapted to withstand the tennile
strain of the shell than the compressive one of the furaace tubes,
which therefore accounts for the shell having been broken up
a pieces, while the famace tubes were uninjured, except by
p effects of the explosion itself."

'"~ s foUovring practitio! remarks from the loport oS VVa ^V'Wi-
' 9 will be axial: —

.d tuUy
^Meformed
^HnBcimen
^H the be

KNGINEEEJNG FACTS,

BETTING BOILERS.

I

I

" Considerable irregularity is met with in the manner in which
many of the hoilers under inspection are set. The external brick-
wnrk Aues of some are so contracted ae to be altogether inacces-
sible, ao that no examination of the plates con be made ; of otheca,
the aide fiuea are of very unequal area, thus unfeirly diverting
the draught; of others, again, they are carried dangerously high,.
being considerably above the low water level; while in i
cases longitudinal seams of rivets run right along the bearing
sarface of the brickwork seating, which not only acceleiates
corrosion of the plates should leakage take place, but at the
same time conceals the injury so that it frequently goes on to a
dangerous extent undetected.

" Careful particulars are taken of the mode in which all the
boilers under inspection are set, and it is thought that a statement
of the dimensions found to he of the best proportions, and now
generally adopted, would be of service to the members, and tend
to prevent the recuiTence of the irrogalahties uid iaconveoienoo
referred to above.

MODE OF BETTINO AN IKTBRNALLY FFRED BOILEB OP 7 FEET
DIAMBTBB.

" The boiler to be carried on two continuous side walls, spaced
4 feet apart in the clear between them. The top courae of these
walls on which the boiler rests to consist of fire-brick blocks,
which can be obtained of any desired pattern, and should, in the
present instance, he of the following dimensions : — Height oi
vertical face, 12 inches; width on the base, 12 inches; width of
bearing surface on which the boiler beds, 6 inches. The angle
of this surface, in. order k) fit the circle of the boiler, should be
38 degrees above the horizontal; this will be best obtained by
striking it out full size in accordance with the foregoing dimen-
sions, which can readily be done by any competent brickBettep,
The back of the blocks should slope down to a thickness of 4^
inches, so as to form an abutment against the brickwork at the
bottom of the aide flues, to prevent the weight of the boilec
ihruatiBg the blocks apart. The top of the side flues to be o
Mire/ with the iurnace crowns, a.ad l\i6 \)ct\>U)^ a^ &\Eti«iL vLUx

I.] MODE OF SETTINO BOlLEIiS.

undfraide of tlie boiler. Their widtli nt the toj) to be <i
inches, thus makiug a distance of 8 feet in the clear betwoQH the

fiice of the aide Sues, which shoiiM Dot fullow tho sire«}> of the
liuiler, as is frequently the ease, but should run vertically from
iiip to bottom, in order to form a pocket-for deposit lo liu in
Without covering aoy of the heating surface of the boUer, aud at
tlie same time to leave room for a man to pass along and examine
the platea. The flue beneath the boiler will be formed by the
eide walls already referred to, spaced 4 feet apart ^ the height
may be about 3 feet, but this is not very material so long as soffi-
cvuiit room is allowed for convenient access. The course of the
tljtme immediately ai^r leaving the furnace tubes, to pass undrr
the l)ottom of tlie boiler; to split at the front eud and return to
the cliimney throngh the two side flues. Generally two dampers
are introduced, one to each side flue. It is important in boilei's
with two plain internal flue tubes, that the course of the flamu
should pass under the bottom before entering the side flues, in
order to promote circulation of the water, and to prevent stniiri-
ing the boiler at the transTBrse aeams of rivets on its under sida,
and causing what is familiarly known as ' seam rending.'

"It is not equally necessary, though still advisable, to pass the
ftames under the bottom hefure entering the side flues of those
boilers which are iitted with tubes or pockets tor quickening the
circulation of the water.

" In cases where the angle iron at the front end plate is ex-
ternal, the dee of the brickwork should be set back some inches,
so that the angle iron may be exposed to view, or leakage may
lake place without detection. The front cross wall underneatli
the boiler need not be more than 4^ inches thick, otherwise it
is frequently found to hai'bour corrosion. This wall should be
recessed so as to leave the hlow-out pipe entirely free, in order
that it may be accessible to examination, not liuble to be strained
by settlemeni of the holier, nor corrosion of the plates accelerated
by contact with the brickwork should leakage occur,

" All the external flues should be faced with fire-brick, ami
set in fire clay, no mortar being allowed to touch the boilur,
especially hulow water line.

ENGINEEIUNG FACTS.

r

^^P "The general arrnugemeiit of flaea should he the a

^H given above for a, holler of 7 feet diameter, and a slight altera-

^B tion only made in detail to allow fot the difl'erence i

^P "For & boiler 6 feet in diameter, the side walls ahoald bo

spaced 3 feeb apart in the clear. The fire-brick hloeta sbonld

be 12^ inches high on the vertical face, 12 inches wide on tha

baae, and 4 inches upon the bearing surface upon which thfl

boiler beds, the angle of this surface iiboye the LoriKontal being

S3 degrees, the other dimenaionH of these blocks remaining a

before. Tlie side flues to be carried down 3 unJies below Ui«

level of the bottom of the boiler, and at the top to be ou a level

Iwith the furnace crowns, this latter, as well as the remaining par-
ticulars, being the same as those for the boiler of 7 feet diameter.
" For a boiler of 5 feet in diameter, the side walls should faft
2 feet 6 inches apart in the clear, the fire-brick blocks Hi
iac\iGS high on the vertical face, 12 inches wide at the base, and
3 inches wide upon the hearing surface apon which the boilef
beds, the angle of this surface above the horizontal being 33

I degrees. The other dimensions of these blocks remain unaltered
from those given above. The side tines to be carried down 6
inches below the level of the bottom of the boiler, and at the top
to be on a level with the furnace crowns, the remaining paiticu^
lara being the same as those for the boiler of 7 feet diameter.
"For boilers of still smaller diameter if a mid-feather be un-
avoidable, it should be fac«d with fire-biick blocks for the boilsr
to rest on, and the blocks bevilled off to a narrow b«anng tmrtuio,
since one of the causes of injury from mid-feather walls, is their
width. For a boiler of 4 feet diameter, the width upon the top
edge need not exceed 3 inches. The flues under all circnmstanoes
^B must be sufKciently lac^je to admit of a man's posaing right
^H through them for the purpose of examination."
^H Another association has been of late originated in Wolver-
^H bampton for the purpose of assuring and inspecting boilers, and
^H called the " Midland Steam Boiler Assorauce and Inepectuin
^H Compaaj." A meeting of this association was held at their
^^M^oo^ Wolrerhamplaa, when, a te^ovb ^i \.W ^aab W^ ^

IT

] REPORTS, 57

1 WHS submitted by E. Martin, ctief engineer. Tlie foUowing i.<
m abstract : —

"I have tbe bonour to report that, up to the euA of 1862,
prirticolars were taken of 2,24S boilers with a view to insptution
J assurance, and that proposals were accepted for the inspection

■ !■ 404: and the assurance of 366, making a total of 770 boilers
^■^iiced nnder the care of the company. This ntiuiber has eince

led to 1,001. The 770 boilers miJer inspection niid
i miiy lie deiicribod under the four following heads ; —
1st Plain cylindrical with round e^-ahaped elliptical or hemi-
spherical endiS, and sometimes with one or more internal flues,
llirougb plain or breeches tubes, but all fired under tbe bottom,
432; 3d Furnace boilers worked by the waste heat fronj the
puddling, heating, refining, charcoal or coking furnaces, either
upright or homontal, with one or more internal tubes, 162; 3d.
Cornish or Fairhairn boilers, with cylindrical shells and one or
more tubes, internally fired, 100; 4th, Low-]iresaure boilers,
either balloon, haystack, Butterley, or wagon, with one or more
flue tubes, 76; total 770. Among tiie purposes for which these
boilers were used are colliery engines for pumping, and 227 are
colliery engines for winding; total colliery engines, 298; mills
and forges, 269; blast fumaces, lOD; pumping engines at canals
Liii.l waterworks, 41; latheenginee, 21 ; clay mills, 18; and for other
iirpoaes, 14, half of which were boUers ut saw mills. The colliery
,,iLi! blast engine boilers are often placed in groups of from two
h' aix, and the mill and forge furnaces are generally in groups
of from five to thirty connected together, which greatly facilitates
the safe working of furnace boilers. All boilers under the in-
apeotiou of the company, whether for inspection or assurance, are
-iibjected to the same exarainalion, which is either external, in-
I'Loal, or thorough, according to the facilities given. The ex-
ii-raal examination is made at any time when the boiler is work-

■ 111,'; the internal is made when the boiler is cold and empty;
and the thorough only when the flues are properly cleansed and
prepared. Tiiere have been made during the balf year ending
December 31, 1862, 868 external, 85 uitetnal, and fi2 thorough
1 (caminations, making a totdl of 1,003 No difliculty has been
■xperienced in making the examinations, as masters and engine-

6 all the hcl^ thi-j can, and your iiiapeaota take ^

f »

ENGINEERISG FACTS. [Drv.

)iil CBueiiig incon^eniencea or neeiileaa tronble. It Las beeq

uecessary to report aoms boilers as in a dnngerous condition, a.

' n all cases the repairs or renewal reoommended has been speedil;

and willinglf done. In same cases neeilless espenditate

I buen prevented by the reports of the result of the exaininatioB

I The chief points needing attention in the tvorlcing of boilen

I under inspection are frequent cleaniug, as Ihe water of the d'

i trict Bcuris a good deal, and is apt to cause the burning of t

plate over the Sre. Tbia fault in the water ie, perhaps, less i

I be dreaded than corroding, as by cleaning the boiler can. be

I BtoTed to its original condition, while corrosion produces a ]

1 inanent injury. Safety valves are generally found over weighl

Pressure gauges are often out of order, and therefore worse tl

nothing, as thay lead to false confidence. Glass water gauge

e niQch neglected, dependence being placed on the float altm

The feed is generally regulated by hand, although self-actil

apparatus nmy be attached to the boiler. Blow-off cocb a

1 frequently neglected or disused, which leads to much estra troaU

'u cleaning, and not unfrequently to danger, ficrew-patchea t

the old-fashioned low-pressure boilers are sometimes causes <

great injuiy and weakness to the boiler, especially wh^ $

small as to have only one bolt in the centre, Tt

brick covering of boilers to prevent radiation often causes nUB

in the shell of the boiler, by being allowed to get q)

< of repair, so that the ^ret gets in, in which case it is worse ^

~ o little boiler power is a frequent cause of diflieQ~

and danger, as siiflicient time cannot he spared for repaii* t

cleaning, so that when oue boiler is off others have to ba f

too Lard. The great objects to be aimed at is to have boileTB,:^

good material and workmanship, nf suitable constmction fbt fl

work it has to perform and the pressure it has to bear, an4 fi

enough fittings of the least complicated kinds to enable j^

attendants to know the esact height of the water and the |

sure of the steam. I would call attention to the gi'eat impQ

i and utility of a periodical applicatiou of the hydraulic test »

I rBorest and least injurious means of detecting faults which w((

escape notice. A suitable apparatus for this pn^

ft.Jcnpt by the company. Dnring the past year tliirty-fiva a:

"" g.bavfl been reported, but I will mention only the a'

Bi'il-KKB.] EXTLOSIONS AND CAUSES, 69

eioiis in tbis neiglibourliooii, and I am !iaj)py to report tliat none
of them are boilere under the inspeotiaii of tlie company. Three
wtre balloon boilers, which burat for want of etajB; one Comisli
biiiler from collapse of tubes; one furnace boiler from the same
riiiisfi, and one npright firing boiler from collapse of the internal
lireplace. la the two latter cases the boilers were of dofective
i;i instruction, and the explosion was eaosed by unusual prKSSurc,
i.'wing to delay for repairs iu the steam hammers wLkrli they
Motked. Both reports wore received and adopted, this retiring
directors and auditors were re-elected, and the chairman and the
other membera of the board of directors were tliankeil. — Tiie
i:hainnan, in responding, spoke highly of the engineer and the
BGcretary, anil said he hoped that, by the extended operations of
tlie company, the number of boiler explosions in this district
would be lessened."

This company held another half yearly meeting at their office*,
Wolverhampton, when Mr. Edward E. Martin, engineer, pre-
i^'.'nted his report for the half-year ending June 30th, 1863, of
which the following is an abstract from the "Engineer;" —

" The engineer's report stated that during the half-year endinjj
Jone 30th last, particulars were obtained of 371 boilers, witli
;i view to proposal for inspection or asautance, whidi, with those
lipfore reported, made a total of 2,616. Proposals had been
nr.Bpted, during the six months, for the inspection of 215 and
LliR assurance of 134, mating together 349 boilers. The total
number of boilers under inspection up to June 30th was 61SI,
:tr\ii under aasorance 500, making 1,119 boilers under the care
I if the company. That number had now been increased to
1.181. The boilers were of the followiaig descriptions; — Plain
r;vliii<lrical, externally fired, 670; furnace boilers, of various
shapes, 235 j Comiah or others, internally fired, 126 ; low-prea-
■lire balloon or wagon-shaped, 88j total, 1,119. These boilers
Here employed as follows; — Colliery engines for pumping, 95;
liitto for winding, 324; mills and forges, 423; blast furnaces,
ITl ; canals, water and gas works, 43; lathe engines, 22; clay
mill^ 32 ; saw mills, 7 ; rope works, 4 ; flour raids, 3 ; locomo-
tives, 3; stamping, 3; total, 1,119. Ali boilers had been sub-
jected to the same careful inspection, nnd, wherever opportunity
voold be given, they had been examined internally and in t\M

UO ENOINEEEINO FACTS. [Dn-.

fliies. Tliere had beBn inaiie during the half-year 1,936 Rxterna
163 interual, aud 337 thorough — iii all 2,486 examination
and both masters anil engine tenters had given every facility fo
these examinations. As the system of inspection became hett«
known still greater beneflt -would, it was hoped, accrue to thti
who placed their boilers under the care of the company, Fif^
five reports bad been sent to owners as to matters requiring
tention, and the recommendations had been speedily carritd o
Care had been taken to avoid causing needless trouble or ta^
peiise. The chief points reported on had been as follow
Alteration of shape from tiie insufficiency or want of proper stay)
or from undue heating, or careless usage, or from injury by a
niulatiriu of scurf, or blistering of plates. The strength of
shells of boilers was frequently found greatly diminished hy ii
efficient repair, especially from the use of little nan
over cracks on the edges of plates, which might effectually jw
vent leaking for a time, but which leaves the plate little, tf an;
stronger than it would he with the crack untouched. Msny
these patches have been foond on a single plate, and they i
last long, as they burn off because the water cannot
them. Safety valvM are very frequently found overweigl
either from inadvertence, or to prevent leaking when the
requires ' scouring.' These valves are of little use unless thfl
are bo adjusted as to lift freely at a few poun<ls above the ordi-
nary working pressure, so as to give complete relief before ttu
pressure can rise to an unsafe height Much danger would 1m
avoided if the practice were more common of having a valve
near each engine, of eufScieut size to let off as much steam ad
that engine usually takes, and within easy access of the man in
charge to open when there is a ' stand.' Safety valves are also
sometimes overweighted to make an engine that is out of repair
do its required work. Attention having been called to this point
iri reports, has led to engines being worked with considerably Ipw
pressure of Hteara, thereby effecting great economy. Pri'twiUB
k Ranges of all kinds are frequently found out of order and iiidi-
k Vftting wisely, but this is more often from unfair usage than frou
F^ttitj' defect in their principle or construction. They are sometiaiM
E^^laced on the steam pipes, and so close to the engine that QhM
BW&trtB trith every stroke, to the great injury of th^u deliaW

BoiLWij StS^I aSB WATffi OAtTGES. 51

niechaaism. Placed in this position tliey often give ijut an ap-
proximate indication of tbe pressure in the boilara, because th«
steam has been drawn through long ranges of esposed pipes ot
small diameter. Al] gauges should he as near as posgiblo to the
boiler, so as to indicate the pressure at which the steam is
' raised," not that at which it is nwd. A good gauge, kept in
perfect repair, frequently apphed to each boiler at taps placed for
that purpose, and the safety valves adjusted by it, would often
bn a greater safeguard than gauges left constantly in exposed
positions. Glass gauge tubes can seldom he kept in order in
ironworlcB, being so liable to breakage. Floats are often universal,
many boilers being fitted with two, but they are too frequently
found working hadtj. Scurf is found in almost all boileia in this
district, varying in thickness and composition. Scurf is only of
consequence on those parts of the boiler exposed to beat. Need-
less injury to plates and rivets is frequently caused by too vigor-
ously chipping to get it off Tlie plates near the fire, however,
cannot be kept too carefully cleaned. Blowpipes would very
much mitigate the evils of scuriing if they were more frequently
used, especially in plain cylinder boilers, and those with fire under
them. Corrosion is seldom met with on the inside of boilers in
this district, but is a moat frei^uunt cause of injury on the outside
fr im the leaking of the steaai pipes and fittings. Thinning of
iti?3 from this cause has been most frequently reported both
i\c and beneath the brickwork, and in many cases to a dan-
' '^u3 extent. In all reports attention is called to anything that
ibserved to lead to injury or expense, as well as to anything
..L-iug present danger. There have been twenty- one explosions
various parts of the country since the begiiming of 1863.
' ve of these had been personally examined and reported on by
■ engineer of this company. They were as follows: — A plain
'.inilrical boiler, with round ends, exploded from rupture over
./ fire, having been weakened by too frequent and inefficient
I'.iir. A breeches tube from the same cause; a plain cylinder,
ih round ends, from burning of plate over the fire owing to
' iiniulation of scurf; a plain cylinder from overbeating through
iiirtness of water; a two-tubo internally fired from undue
■ I'-^sure."
Perhaps some apology is necessary for the great length of the

4

r

I

ENGINEERING FACTS.

KODB OF SBTTINO INTERKALLT FIRED EOUJIRS O

" The general arrangement nf flues bUouIiI be the »
given above for a bolli;r of 7 feet diameter, and a slight e
tion only made in detail to allow for the difference in sise.

" For a boiler 6 feet in diameter, the side walla aboald I
B[>aced 3 feet apart in the clear. The Hre^brick blocka shosl
be 12j inches high on the vertical face, 13 inohea wide on (*
base, and 4 inches upon the bearing surface upon vbidi t
boiler beds, the angle of this surface above the horizontal 1;
33 degrees, the other dimensions of these blocks remaining
before. The side flues to be carried down 3 inches btslow tl
level of the bottom of the boiler, and at the top to be on a 1m
with the furnace crowns, tbia latter, as well as tlie remaining yt
ticulare, being the same as tho^e for the boiler of 7 feet diam^

" For a boUer of 5 feet in diameter, the side walla should fe

2 feet G inches apart in the clear, the fire-brick blocks lli
inches high on the vertical fece, 13 incbes wide at the base, b

3 inches wide upon the bearing surface upon which the b
beds, the angle of this surface above the horizontal being 3i
degrees. The other dimensions of these blocks re
from those given above. The aide flues to be carried dom '
iiches below the level of the bottom of the boiler, and at thiS h
to be on a level with the furnace crowns, the remaining parflm
lais being the same as those for the boiler of 7 feet diametan

" For boilers of still smaller diameter if a mid-feather be Ht
avoidable, it should be faced with fire-brick blocks for the t
to rest on, and the blocks bevilleil off to a narrow bearing «
since one of the caaaea of injury frfim mid-feather walls, is UlHI
width. For a boiler of 4 feet diameter, the width upon the to
edge need not eiceed 3 inches. The flues under all circamataMI
most be stilficiently large to admit of a man's passing i^
through them for the puqjose of examination."

Another association has been of late originated in Wolvsi
punpton for the purpose of assuring and inspecting boilera, M
psHed the " Midland Steam Boiler Assurance and T
ffiinpariy." A meeting of tWs assoMtAvjiv "waa W\A at tha
Ifeflft Woi vcrlianipton. when a report 'ioi ft\« V*'*' ^^"^^

Boilers.] REP0RT3. 57

ivas submitted by K. Martiii, chief eugiueer. Tlie foUuwiug L*
iTi abstract ; —

" I have the honour to report that, up to the end of 1862,
p;irticular3 were taken of 2,245 boilers with a view to inepottioii
iir assurance, and that proposals were accepted for the inspection
of 404 and the assuratice of 366, making a total of 770 boilers
placed under the care of the cijinpany. This number has since
Ireen increased to 1,001, The 770 boilers under inspection and
assurance may be described under the four following heads: —
1st Plain cylindrical with round egg-ahaped elbptieal or hemi-
spherical ends, and aometiraea with one or more internal flues,
through plain or breeches tubes, but all fired under the boltHUi,
132; 2d Fumaoe boilers worked by the waste heat from tliB
|iuddling, heating, refining, charcoal or coking furnaces, either
upright or LoriKoutal, with one or more iuternal tubes, 1C2; 3d.
Cornish or Fairbaim boilera, with cyliniirical shells and one or
mure tubes, internally fired, 100; 4th, Low-pressure boilers,
either baUoon, haystack, Buttcrley, or wagon, with one or more
flue tubes, 76; total 770. Among tlie purpose (or which these
boilers were used are colliery engines for pumping, and 227 are
colliery engines for winding; total oolliory engines, 298; mills
and foi^s, 269,- Wast furnaces, 109; pumping engines at canals
and waterworks, 4 1 ; lathe engines, 2 1 ; ulay nulls, 18 ; and for other
purpoaea, 14, half of which were boilera at saw mills. The colliery
iind blast engine boilers are often placed in groups of from two
tii sis, and the mill and forge fnrnaoes ate generally in groups
lit' from iive to thirty connected together, which greatly facilitates
tlie safe working of furnace boilera. All boilers under the in-
-.paction of the conijiony, whether for inspection or assiuance, are
subjected to the same examination, whieh is either esternal, in-
ternal, or thorougli, according to the facilities given. The ex-
li^roal examination is made at any time when the boiler is work-
ing; the internal is made when the boiler is cold and empty;
and the thorough only when the flues are properly cleansed and
prepared. There have been made during the half year ending
December 31, 1862, 868 external, 85 inteinal, and S2 thorou^
■ xaminations, making a total of 1,003, No diffiiexAtj \iaa'\«Ktt
I xperiencarf in making the examinations, as raasteTs aai en^iw
ui,^^ye. «ZZ lUe Laiii they call, and yaas uwpeeWjta <«iia 1

ENGINEERING FALTS.

"The general airaiigement of fiaes should be the same » th»
given above for a brillur of 7 feet diameter, and a slight i'
tion only made in detail to allow for the difference h

1 boiler 6 feet in diameter, the aide walla abould ft
spaced 3 feet apart in tlie clear. The Jire-brick blocka abooli
be 12^ inches high on the vertical face, 12 inches wide on t~
boae, and i iachea upon the hearing etiriace upon which t
boiler beda, the angle of tliia surface above the horiitoHtal 1
33 degrees, the other dimensions of these blocks remaining a
before. The side flnea to be earned down 3 inches below tl
level of the bottom of the boiler, and at the top to be on a lev
with the furnace crowna, this latter, as well as the remuning pi
ticulars, being the same as those for the boiler of 7 feet diameten

" Per a boiler of 5 feet in diameter, the side walla should, i
2 feet 6 inches apart in the clear, the fire-brick blocks 14i
inches high on the vertical face, 12 inches wide at the basa, at
~ " 3 wide upon the bearing surlace upon which the boilei
beds, the angle of this surface above the horizontal being 33
degrees. The other diraeuaions of these blocks remain nnalte
from those given above. The side flues to be carried down (
inches below the level of the bottom of the boiler, and at ^ tc
to be on a level with the furnace crowns, the rema
lars being the same as those for the boiler of 7 feet diametsi

"For boilers of still smaller diameter if a. miJ-feather be 01
avoidable, it should be faced with fire-brick blocks for the boill
to rest on, and the blocks bevilled off to a narrow bearing sm&g
since one of the causes of injury frfim mid-feather walla, a t&0
width. For a boiler of 4 feet diameter, the width upon the *!
edge need not exceed 3 inches. The flues under all circamatBiiol
must be sufficiently large to admit of a man's passing ri^
tliruugh them for the purpose of ezainination."

Another association has been of late originated in Wolw

liampton for the purpose of assuring and inspecting boilei^ M

~ Balled the " Midland Steam Boiler Assnrance and Inspecttu

•mpany." A meeting of this association was held at t
"ffolverhampton, when a report for the past I

Bdilzbs.] ItEPORTS. G7

*(is submitted bj E. Martin, chief eiiginner. The follgwiiig i.i
»n abstract; —

"I have the honour to report tbat, up to the end of 1862,
particulacs were taken of 3,34fi boilers with a view ta inapectioti
iir assurance, and that propusals were accepted for the inepectiun
i-r 40+ and the a.sBUcaiice of 366, raaking a total of 770 boilers
j.laced under the care of the company. This number has auice
l>-eu increased to 1,001. The 770 boilers under inspection and
ii.isurance may be di;scri1>ed under the four following heads : —
Int Plain cylindricftl with round egg-shaped elliptical or benii-
e]>hericsl endi^ and sometimes with one or more internal flues,
Ihroagh plain or breeches tubes, but all fired under the bottom,
432; 2d. Furnace boilers worked by the waste heat from tho
[luddling, heating, refining, charcoal or coking furnauea, either
upright or horizontal, with one or more internal tubes, 162; 3d.
Cornish or Fairbaim boilers, with cylindrical shells and one or
uniro tubes, intenially fired, 100; 4th, Low-pressure boilers,
either balloon, haystack, Butterley, or wagon, with one or more
flue tubes, 76; total 770. Among the purposes for which these
Iniilers were used are colliery engines for pumping, and 327 are
colliery engines for winding; total colliery engines, 298; mUIa
iind forges, 269; blast furnaces, 109; pumping engines at canals
and waterworks, 41 ; lathe engines, 21 ; clay mills, 18; and forother
purposes, 14, half of which were boilers at saw mills. Tlie colliery
and blast engine boilers are often placed in groups of ftom two
tg six, and the miU and forge furnaces are generally in groupa
i)f from five to thirty connected together, wliich greatly facilitates
the safe working of furnace boilers. All boilers under the in-
spi-ction of the company, whether for inspection or assurance, are
subjected to the same examination, which is either external, in-
ternal, or thorough, according to the facilities given. The px-
terual exaniination is made at any time when the boiler is work-
ing; the internal is made when the boiler is cold and empty;
and the thorough only when the flues are properly cleansed and
prepared. There have been made during the half year ending
December 31, 1862, 868 external, 85 internal, and 52 thorough
rsamiufltiona, making a total of 1,003. No difficulty has been
i.xperienced in making the examinations, as mnsters and engine-
e all the iiolp they can, and j"our iusv^*^^^* ^''■^ '^

I

ENGINEERING FAfTS. fDn-. I.

bi avoid causing iiiconvenieucea or needless trouljle. It haa been
necessary t<i report some toilera as iu a dangerous condition, and
" cases the repairs or renewal recomiueiided haa been speedily
and willingly done. In some cases needless expenditure has
been prevented by the reports of the result of the examination.
The chief juints needing attention in the working of boileia
under inspection are freqnetit cleaning, as the water of the c"
l^'ict Bcuifs a good deal, and is apt to cause the baming of tho
plate over the fire. TLis fault ia the water ia, perhaps, less to
be dreaded than corroding, as by cleaning the boiler can be »-
stored to its original condition, while corrosion produc
manent injury. Safety valves are generally found overweighted.
Pressure gauges are often out of order, and therefore worse thaiL
nothing, as they lead to false confidence. Glass wat^ gau^;
are much, neglected, dependence being placed on the float alona.
The feed is generally regulated by hand, although self-acting,
apparatus may he attached to the boiler. Blow-off cocks are
frequently neglected or disused, which leads to much extra tronblft;
ill cleaning, and not unfrequently to danger. Screw-patchea on
the olii-faahioned low-pressure boilers are sometimes c
great injury and we.ikiieas to the boiler, especially when the
patch is so small as to have only one holt in the centre. Tho
brick covering of boilers to prevent radiation often causes mvclii
corrosion on the shell of the hoiler, by being allowed to get out
of repair, so that the wet gets in, in which case it is worse ^ai^
none. Too little boiler power is a frequent cause of diffioulty.
and danger, as sufficient time cannot be spared for repairs c
cleaning, so that when one hoiler is off others have to be fired.
too hard. The great ohjects to be aimed at ia to have boilers ot
good material and workmanship, of suitable constrnction for tfaft
work it has to perform and the pressure it has to liear, and just
enough fittings of the least complicated kinds to enable the
attendants to know the exact heiglit of the water and the pres-
sure of the steam. I would call attention to the great importanoa.
and utihty of a periodical apphcation of the hydraulic teat as the,
surest and least injurious means of detecting faults which woijlil'
otherwise escape notice. A suitttble apparatus for this purpose,
is kept bjr the company. During the post year thirty-five explo-
pos have been lepotted, but X will uient^LQO. (lul's i\w ^a;

BoiLBKs.] EXPLOSIONS AND CAUSES. 50

sinus in this neighbourhood, and I am happy to report that nmic-
of them are boilers under the inspeution of the company. ThreH
were balloon boilers, which bnrat for want of stays; one Cornish
biiiJer from collapse of tubes; one furnace boiler ii'om the Biinie
uauae, and one upright firing boiler &om collapse of the internal
fireplace. In the two latter caaea the boilers were of dpfective
conBtruction, and the explosion was caused by unusual pressun",
owing to delay fur repairs iu the steam hammers wLich tliey
worked. Both reports were received and ailopted, the retiring
directors and auditors were ro'elected, and the cliairman and the
other members of the board of directors were thanked.— The
chairman, in responding, spoke highly of the engineer and the
secretary, and said he hoped that, by the extended operations of
the company, the number of boiler explosions in this district
would be leasMied."

This company held another half yearly meeting at their offices,
Wolverhampton, when Mr. Edwaid E, Martin, engineer, pre-
sented his report for the half-year ending June 30th, 1663, of
which the following is an abstract from the "Engineer:" —

" The engineer's report stated that during the half-year ending

Tune 30th last, particulars were obtained of 371 boilers, with

:i view to proposal for inspection or assurance, which, with those

before reported, mado a, total of 3,616. Proposals bad been

accepted, during the six months, for the inspection of 215 and

the assurance of 134, making together 349 boilers. The total

number of boilers under inspection up to June 30th was 61!),

irul under assurance SOO, making 1,119 boilers under the care

t ihe company. That number had now been increased to

] ls4 The boilers were of the foBowLng descriptions: — Plain

Inidncal, externally fixed, 670j furnace boilers, of various

ipcs, 235, Cornish or others, internally fired, 126; low-pres-

10 balloon or wagon-shaped, 88; total, 1,119. These boilers

■ Lie employed as foUows; — Colliery engines for pumping, 95;

iliUo for winding, 324; mills and foi^es, 423; blast furnaces,

171; canals, water and gas works, 43 ; lathe engines, 22 ; clay

fJiilla, 22; saw mills, 7 ; rope works, 4; flour mill s, 3; looomo-

:ves, 2; stamping, 3; total, 1,119. All boilers had been sub-

i'[«rl to the same careful inspection, and, wherever opportunity

iild be given, they had been examined iuteraalVj aii4 va *i«

I
I

BO ENGINEERING FACTS. [Dm 1

flues. Tliere bad been made during the half-year 1,986 external,
163 interoal, nnd 337 thorough — in all 2,486 examiitationa
and both mastera and engine tenters had given every facility fi
thege examinations. Aa the system of icspeotion became bettel
kunwn etill greater benefit would, it was hoped, accrue to thn«
who placed their boilers under the care of the company, Fifty-
five reports had been sent to owners as to matters requiring at-
tention, and the recommendations had been speedily carried on&
Care hail been taken to avoid causing neeiUess trouble or ex-
pense. The chief points reported on had been as follow: —
Alteration of shape from the insufficiency or want of proper ataya,
or from undue heating, or careless usage, or from injury by acco-
niulatiun of scurf, or blistering of platen. The atrengtb of tlH
shells of boilers was freqnently found greatly diminished by iUi
eflicient repair, especially from the use of little narrow patcha
over cracks on the edges of plates, which might effectually pre-
vent leaking for a time, but which leaves the plate little, if any,
atronger than it would be with the crack untouelied. Many u
these patches have been found on a sin^'le plate, and they selfton
last long, as they burn off because the water cannot reach
them. Safety valves are very frequently foimd overweighted^
either from inadvertence, or to prevent leaking when the v*l«
requires ' scouring.' These valves are of little use
are bo adjusted as to lilt freely at a few pounds above the ordt
nary working pressure, so as to give complete relief before t^^
pressure can rise to an unsafe height. Much danger would I
avoided if the practice were more common of having a i
near each engine, of sufficient size to let off as much steam I
that engine usually takes, and within easy aceeas of the man iR
chai^ to open when there is a 'stand.' Safety valves
sometimes overweighted to make an engine that is out of r^iaii
do its required work. Attention having been called to this poin)
in reports, has led to engines being worked with considerably les^
pressure of steam, thereby effecting great economy. ~
gauges of all kinds are frequently found out of order and ind»
eating falsely, but this is more often from unfair usage than front
any Uefeot in their principle or construction. They are sometimea
pJaced on the steam pi[>es, and so close to the engine that Ui^
witb every stroke, to the great Hi.i*Ma \& SluMet:.^ "

rutna.] STEAU AHD WaTEB OAUUES, «1

.:liaiiisiii. Pliiceil in this poEttiim tliey often give but an ■[■-
{irojcimatc iudicatiun of the presEUHi in the boiliira, bccaiis« Um
steam has been drawn through long ranges t>f exposed pipes ut
-nunil diameter. AU gnnges should be as near ae ptMsible to tlif
hotler, so oit to indicate the pressure at which the eteam U
' raised,' not that at which it is used. A good gauge, kept in
perfect repair, frequently applied to each boiler at taps placed fur
that purpose, and tlio safety valves adjusted by it, would often
bn a greater safeguard than gauges left constantly in ex{ios«l
jioeitions. Glass gauge tubes can seldom be kept in order in
-unworki^ being so liable to breakage. Floats are often universal,
iniiy boik'ts being fitted with two, bat they are too frequently
.;iid working badly. Scurf is found in almost all boUeis in this
-U'ict, varying in thickness and composition. Scurf is only of
<aseqai-nce on those parts of the boUer exposed to beat. Neod-
1-'^ injury to plates and rivets is frequently caused hy too vigor-
ously chipping to get it off. The plates near the fire, however,
cannot be kept too carefully cleaned. Blowpipes would vury
mach mitigate the evils of scurfing if they were more frequently
used, eqiecially in plain cylinder boilers, and those with fire under
them. Corrosion is seldom met with on the inside of boilers in
this district, but is a moat freqnent cause of injury on the outside
from the leaking of the steam pipes and fittings. Thinning of
plates from this cause has been most frequently reported both
above and beneath the brickwork, and in many cases to a dan-
gerous extent. In all reports attention is called to anything that
is observed to lead to injury or exjtense, as well as to anything
causing present danger. There have Leen twenty-one explosions
in various parts of the country since the beginning of 186'3.
Piva of these hail been personally examined and reported on by
the engineer of this company. They were as follows: — A plain
cylindrical boiler, vritb round enda, exploded &om ruptnre over
the fire, having been weakened by too frequent and inefficient
ri-pair. A breeches tube from the same cause; a plain cylinder,
with round ends, &om burning of plate over the fire owing to
accunmlation of scurf j a plain cylinder from overheating through
sUortiiesa of water; a two-tube internally fired &om undue
pressure."

Perhaps some apology ia aeceas&iy for the gr6a.l Yengjita, oi ^\ft

ga ESGINEEBING FACTS. [Dr

furegoing reports; these, however, comprise only a very t
jiortion of the experience of this valuable asBociation ; and v^hu
we consider the immense importance of past failure to the futui
suceeaa of any pursuit, apology will so fac be umieBeasary.

Recapilviatory Reviarka on Bailer Explosions. — The ca;
Imiler aspbsiona may be briefly recapitulated as follows :-
First, from original faulty oouatruction ; and secondly, frtri
careless attendance. Under the first cause not only ia t"
conatmctioE and des^n. of the boiler involved; but also t
efficiency of all mountings, &c, for the purpose of indicating d
internal condition of the boiler. The safety-'Ottleeg should be c
BtiSicient srea to carry off all the steam capable of being g
rated by the boiler, and on no account ahould stiifling boxes, o
even glanda, be fitted to the spindle of the safety-valve, nnles
considerable piay be allowed for such. Another c
of annoyance in safety-valves, and a frequent cause of accidenl
is the sticking of the lever in its joint Frequently aueb 1
are made a good fit ia the joint as also the pin; the c
is, that in blowing off once or twice, the joint gets rusted, a
the pin, and we have fi'equently seen the whole force of a moi
applied to the end of a two-feet lever, and without being abla b
raise it. It ia not to be wondered then, that with the additioi
of the weight or spring balance upon a lever fast in its joint, t]
fxceasive pressnre should be generated in the boiler and expla
pion inevitably follow. Now this joint not only seizes ths jui
but also the sides. of the lever, so that we have sometimes found i
necessary to introduce brass washers bet neen the sides of the joinl
while a liard brass pin was passed through the joint Thia phw
effeutually prevents the lever being held fast by rust or any otlw
cau,se. Perhaps a better plan still, although not the most eleganl
is to make the joint sintiiar to the seat for the fulcrum of a pair 6
scales, while a wedge-shaped steel fulcrum ie keyed fast in ttii
end of the lever. In such a case there is no chance of the leve
getting fust, while the friction is reduced to a minimnm, and thi
balance most perfect. Too much csre cannot he bestowed apoa
safety-valves, considering the vital neoesaity there is to have si
appliances tfi ensure the safety of the boiler.

Another fruitful source of accidents, as already illustrated ii
u£e repoiia of the Manchester Aaaocioitiou, u ti deficiency in ti

Bol

S?I5s!r^'"SEHAEiiS CS BOILEK EXPL0S10K5 63

miter guppli/; this, in i!ue course, brhiys us to tlie coneideivitiiiJi
uf tlie apponttua designed Lu iiidicDto Ciie state of tlie wiiter-levei
in eteaoi builers.

There are mauy and various forms of such appamtas, tIjQ must
eommon being tbo gauge-glass. On tlus subject we cannot do
Tietter than quote the following able article from the Mechanics
Magazine: — "Although it is quite certain that a red-hot fire-box
uaimot generate sufficient steam to explode a boiler, it is equally
L-ertain that any over-ii eating due to too low a water-level, is not
uuly injurious, but, if often repeated, absolutely destructive to
either the bottom plates of a boiler, or the top of a iLre-box, aa
the case may ba ; henee a few words on the best means of ascer-
taining, at all times, the precise level of Jhe water within & boiler,
may not prove uninteresting.

" Were it possible to construct a boiler of glasa, many pheuu-
mena doubtless, connpcted with the relative generative powers of
different regions of the boiler, the mode in which primiug takes
place, the deposit of sediment, &c, would become so evident to a
careful observer, that many useful deductions miglit be drawn
from tbe infoHnation bo gained; hirt aa boilew are inTariably
constructed of opaque materials, all information regarding the
state of affaire within, must be described from sources more or
less indirect. A patent has, it is true, been taken out for tha
iipplication of a powai-ful lens — ^or telescope, in fact — by means
ijf which the observer, aided with a strong light cast within tlie
boiler, by a lamp and a second lens, can wholly or partially learn
all that goes on within; such an invention not being likely to
meet with very general adoption, we need not dwell further on
ita merits or demerits, bat tarn to those watei'-gauges met with

" The first we have any mention of in the historj' of the steam

engine is the single gauge-cocks, flwt applied by Savery ia the

year 1698. Its application was anfficiently obviona — it was

i.ii.ruly making a hole in the side of a vessel through wliich water

I'ild flow when it had reached it. Shortly afterwards Savery

iqdoyed two of these cocks in onler that the water level might

iiscertained with greater accuracy. Those gauge-cocks are in use

the present day, but, in our opinion, frequently do more harm

. iTi good; it i« almost impossible, when tho steitm is of b

I

I

6i ENGINEEHING FACTS. [Drv

ci'uaiderable pressure, to asuertmu whetlier water or steam esoap^
tVi>ni them. Water, by its oontained lieat, is almost instantlj
liissipaterl in spray and steam when the luwer cook is opened]
mid as it always rises tu any opening near its lurel, the appei
couk will discharge it plentifully, even, though the real ^
level is at the instant several iiicbes helow it; hence they a
almost totally useless for tubular boilers, unless we adapt si
such arrangement as that employed by Mr. Gooch in a
locomotives. He affixed a hiuas tube of small diameter bo the
boiler in exactly the same way that a glass gauge is fitted ;
thiB tube the gauge-cocka are screwed. In order to test the levd
of the water, open both cocks communicating with the verttccd
pi^>e for a few minutes, then close them, aud open a small o
nil the top of the tube, which will discharge the steam contained'
ill it; then, on opening the gau^-cocks, the uact level of the
water within the tube, and of ciui'Se witliin the boiler, may be
ascertained with certainty, as the water issues quietly by its o
gravity from the gauge-cocks.

" The ordinary gauge-cocks may aometimea be applied i
propriety to large boilers without insiiie flues, as the variation of
the water-level through a range i>f nine or ten inches is seldom
of much importance, and in many situations where boilers g
little cared fur and glass gauges are liable to be broken, they pos-
sess a certain auiount of value.

" But the most popular gauge for such situations, and indeed
tlie only one used in m:my parts of England, is the float; only
appUcable to stationary boilers, of course. This, if properly coi
sti'ucted at first, anil treated with moderate care afterwards, t
areicicliued to consider second to none; its cleanliness, aud tfaa
lar^e range of indication wliich it gives, render it on extramelj*
valuable instrument; but, when badly constructed and neglected.
for long periods, it is undoubtedly more likely to give falsa indi-
cations titan the gUss wai«r-gauge. The most usual arrange-
ment is a stone float suspended from a wire, whidi, paasin^
through a stufiing-hox, is attached to a small cjiain, which r
over 3 hght iron pulley, a foot or more in diameter — the otbei
end of the cliain carrying a weight which partly balances the atone
within the boiler, so as to keep it floating ; but as the stoae is
seldom vBiy large, and acts directly on tbc mrc, it is very easy,

PtOAT IITDICATOR.

f^ e^wing the glaud of the stuffing-box li.o tight, to rentier it
altogethei' inoperative. The use of iroa wire in such a situation
will also be certain to induce corroaion, and the consequent de-
struction of the etufOng in the box.

" The proper method of fitting a float is undnnbtedly the fol-
lowing: — Let a lever of considerable length be hung on a ful-
I rnm within the boiler; one end of thia lever must be so bent as
ro reach above the water-level, and must carry, a caat-iron ball
sufficiently heavy to balance enough of the weight of a float,
moulded and burned in hard brick, fixed to the other end, that
it shall be only half immersed in the water. Outside the boilei
a light index lever must be fitted, to the short end of which a
line brass wire is attached, and being passed through a small
brass atufHng-hox, ia fastened to the float lever within the boiler
close to the fnicmm; any amoimt of fi'iction in the stuffing-bnx
can scarcely affect the action of the float, from its powerful lever-
age ; and the light index outside can be made to traverse through
a sufficient distance to show the most minute variations in the
water-leveL

" A "vory effieient float indicator can also be made by fixing a
hollow ball sufficiently strong to stand the pressure, and light
enough to float, on the end of a lever, of very considerable length,
which will lie parallel to the axis of the boiler. The fulcrum of
the lever must consist of a brass ball fitted into a stuffing-box on
t)ie boiler end, the lever being prolonged a few inches through
:he stuffing-box, and attached as before to a suitable index. It
'.'.i-tuld be impossible, from its great leverage, to set this float fast,
111 matter how tightly the packing might be screwed down, and
I good india-rubber stuffing would last many months, owing to
'• lie almost inappreciable amount of motion in the ball. Such a
.^auge would, we have no doubt, be certain in its action, and
■ ijuld scarcely get out of order.

■' The most generally applicable of all, ia iindoubtedly the glass
:nhe, which, for boilers in motion, such as locomotives, marine
iiiiilers, &c, ia absolutely invaluable.- Its mode of application
k'servefi far more attention than it usijally receives, the almost in-
variable practice being to fit it to the fire-box end of boilers,
from the belief that there it will show exactly the amount of
water over the fire-box, and because practically it is almost tha

I

C6 ENGINEERINtS FACTS, [Dii.-. I.

only place where suitalile apace can be found fur it; but a
water-level is alwaya very uneteady thereabouta, ita iadications
are aeldoni very accurate, especially if the engine draws ita steam
from the same end of the boiler. In traction engines, in parti-
calar, -we have seen the gauge fill and empty many timea i
minute from the oscillation of the water, due to a rough road in
a great measure. We would recommend the use of two tubea^
one extending horizontally &om the top of the glass nearly to the
forward end of the boiler, where ebullition is least; the other in
a aimilar way fi'ora the bottom of the glass. The end of this
last should, of course, be snapended exactly at the minimnm
water-level; and the tube should slope from the gauge tha
whole way, so that water may not loilge is it and cause a &lsfr
indication.

"Glass gauges ate unhappily very liable to become stopped]
up, by the connections with the boilers getting filled with sedi'
nient ; a remedy is not easily found, as any enlai^ement of tha
holes in the cocks and oonnecting-pipea might lead to very aeri"
ous results should the glass tube burst. Some difficulty, too, i
found in getting tubes which will keep clear under a very heavy
pressure; we have seen four tubes put in one after another ii
locomotive working with 1 30 lb. steam in the course of an hour,
although the same glasses answered admirably in a boiler work-
ing with 25 lb. steam; very high-pressure steam dissolves the
glass, rendering it dim, soft, and brittle. Green gloss tubes are
fer the beat.

" Some makers case their gauge in a slotted brass tube;
do not advocate the practice, none but an awkward fireman will
break them by a blow, and they render the tube very difBcult to
keep clean, beeides generally entailing some trouble in replociiig
or packing them.

" For locomotives, marine, and traction engines, we etrongly
recommend the use of two glass gauges; the second to replacs
the ordinary almost useless gauge-cocks. The first gauge should
be short, and litted as wa have already proposed ; the second,
fitted in the usual way, should be of very considerable length,
say twenty to thirty inches, with a mark about the middle to
show the exact top of the fire-box; in many cases the engineer
V^Set his watei short — imte mi. fA t\wi orduiM^j gjaaa ia iaet

H.J RESULTS OP BOILES EXPLOSIONS. 67

■yet it may be very iuconTeuient, if not imposeilile, U> stop

i draw the fire, and he, depeuding on the fact that his gauge
> fitted a£ to just empty wlien there is still an inch or

u of water on the top of his bos, may go on until irrvparable
mischief ta done. T}ie second gauge would show exactly how
tW he might go in such a case with safetj. On the other hand,
ity reaching to the top of the boiler it would show, if his oi\li-
nary glass were fall to the top, exactly liow mucfa steam space
he had left The second glass, loo, will prevent the necessity for
tho replacement of a burst glass untU a convenient opportunity,
and as both are very unlikely to get stopped up at the same
time, will prevent such a mistake as a full glass with an empty
boiler — a matter of very common occurrence. The additional
expense will be very little, compared with the security and com-
fort of such an arrangement.''

BesideB efficient water-gauges, «tcitm-gaufjes are absolutely
necessary to the safe worfeing of a steam boiler. These, how-
■.-ver, have been fully noticed by the reports of the Manchester
Association, and therefore we need not further comment upon
them hei«. The second cause of boiler explosions, namely, in-
attention of " engine tenters " w Jiremen, points to the necessity
of not only maintaining a rigid system of watchfulness over the
characters aqd behaviour of such men, hut the adoption of simple
self-acting apparatus by which the danger of having low water
and ejtcesaive steam in boilers under their care, should be placed
beyond the bounds of posaibiUty. To prevent the first named
of these evils a valve, by which either the fire should be extin-
guished or the steam allowed to escape &om the boiler, by pre-
ference the former; to prevent the second evil a perfectly effi-
cient safety-valve, which, by means already specified, should
neithor be liable to stick or permit the possibility of over-
loading; these are both essential

The results of boiler explosions are very astounding, and have
given rise to several theories respecting the unaccountable force
liborated during explosion; we believe, however, the '' projectile
theory," first explained by Mr, D. K. Clark, to be the one which
ujost fully accounts for such a fearfully rapid generation of
power or destructive effect Without going into this tiUwiVj u\
•lnU^lf it Bia^ III! very Htlj' iiJostrated by an aauA vaiaJiX'bV

r

I
I

63 ESGISEERIKG FACTS. [Dn-.

namely, Giffard's injector, of the Hction of wliich probably most
of our readers are aware. We all know the esceas of power
given out by auch an instrument over tlie initial toiler preaaure,
this being entirely due to the prajection of the water at a high
speed by the steam, and therefore gaining a consideraWe
men turn.

Ha\-iiig considered this, then the theory of boiler exploi
is simple. A lai^e quantity of water exista under say SO lbs.
square incb steam pressure, tbe temperature of this being nearly
300° Fahr., a fracture in the plates of the boiler containing
takes place, and a portion of this pressure is suddenly relievedi.
occasioning a corresponding flashing off of a portion of Has
highly heated water, or — as Mr, Fairbairn has it — " liquid
ateam," which not only follows up the effect of the first poitic
of steam, but carries with it a great portion of water, which being,
a ponderous body, is projected with tremendous force against the
sides of the remaining plate, or whatever opposes its conne.
Tide may he considered as a sufticiently conclusive, if not amply
stated, explanation of the cause of such fearful and disastroui
results attending boiler esplosiona.

Before oonoluding the subject of boilere, it may be as well tc
state, that the tendency to increase the working pressure of boilers
is decidedly an upward one, and that, therefore, the attention of
engineers should be directed to the construction of vessels which
shall, with a minimum amount of material, withstand a maximum

pressure.

Homogeneous metal or mild steel has recently been much
employed as a material designed for the manufacture of boilers,
and as far as it has been employed it seems to have yielded
good results.

On the subject of high pressures, and steel as a matenol for
boilers, we quote the following from the " Mechanics' Magazine,'
that on steel being an extract from the " Verhandlnngen des
Vereins zur Befoerderung dea Gewerbfleisses in Preusser's," by
Dinglern " Polyteehnisches Journal :" —

" Boiler explosions have occurred ever since the day water was
fii'st boiled in a closed vessel; and boilers will explode, for any-
thing we can see to the contrary, to the end of time. We feel
t hesitation in endoraing the ■wotAaot'DT. MWw, aiid Tejjarft-

iloaEK8.j WORKING PRESSCRES OF BOILERS. 99

iug, tliat our gn-st giiicliug principle should be ' so to cuiiatract
the boiler that its explosion may not he dangerous' n result
easily attained by generating the steam nithin email tubes, or
ilttt spaces strongly stayed, so that the boiler really cotiBists of an
L^semblage of sraaJl generatoi«, more or less detached and distinct
■iLo firom the other. By this means, not only is great strength
.-ccured, but the qiiantity of steam and water to be suddenly dis-
persed is so much reduced that little danger caa result iniiu an
exploBion. Tbe small tubes are invariably the weakest parts of
sucb boilers, and being thin, they open quietly, without flying in
i.iieces; Lence non« of the destructive results due to the propol-
non of heavy masses of metal to great distances can ensue.
Boilejs of this construction ore usually termed ' tubulous,' to dis-

BHnmiiah them from 'tubular boilers,' in which, instead of the
tubes containing steam and water, they are made use of as
to convey the products of combustion to the chimney.
Tery excessive pressures have been raised years ago iu these
ous boilers — pressures, indeed, before which anything we
now see in daily use anka into inBigiiificaiice. Jacob Perkins has
employed a prosaure of 500 lb. on the square inch for propelling
ballets ; Dr. Alban, of Plan, in Meeklenbuig, worked an engine
^^U London, many years ago, at a pressure of 1,000 lb. on the
^^M)are inch with the greatest sucoesij. Perhaps the nearest ap-
^^^■taeh we have had to these pressures of late years, was in an
^^^^ne exhibited at the Agricultural Show at Salisbury in 1867,
^^oy Mr. Collinaon Halt This engine was worked at a pressure
of 300 lb. to the square inch, and gave an indicated horse-power
for each 1'25 lb. of coal consumed per hour. The boiler was,
we beheve, of the upright tabular class, some 2 ft 6 in. iu dia-
meter, and 6 or 7 ft. high, with a circular fire-box in the lower
part, and 40 or 50 vertical flue tubes passing through the wnt«r
and steam (which last they superheated considerably) to the up-
take. The explosion of such a boiler as this would of course be
attended with disastrous results if the outside shell gave way.
And although such boilers are very compact, and capable of
atMiding very high pressures with sa&ty, yet they are in general
so subject to priming, and difQcult to clean, deposit settling in a
hard mass on the crown of the lire-hox, from which tt coKaQt ^
remeivd, that their use is aeldom or never to W rwsoimiisiiAsii-

p

I

I

70 ENGINEEKING FACTS. (Div. I-

Mr, Hall is not, of course, the inventor; it would be difficult
indeed to say who is.

" Mr. Martin Benson invented and patented a very good form
of high-pressnre boiler three nr four j-ears ago. As it ■>
brought a good deal before the notice of the public at the tim^
our readers Tnaj perhaps be sufficiently acquainted with it to
prevent the necessity of a detailed description, for which we haT«
not space. It consists of a great number of small tubes travers-
ing H vertical fire space; the ends of all the tubes are bo i
nectod by a very simple and ingenions arrangement, quite pro-
tected from the action of the fire by the side walls, as we may
call them, of the fire space, that they become one. A vertical
receiver of considerable height and moderate diameter is placed
at tlie side of the generator. A small pump, fixed at the bottotn
of this, and worked by the engine, forces the water in a ci
tinuous current through the tube. Entering at the bottom anil
passing backwards and forwards through all its windings, it ia
disohargeil at the top, mingled with steam, into the upper part
of the receiver, or steam cheat, where the water, separating from
the steam, falls to the bottom, while the steam fiows through a
suitable pipe to the engine. Tliis boiler is said to have g'
very good results, but has cot hitherto met with much fevonr,
owing to a prejndice against the use of the circulating pump.
■Whether an injector would better answer the purpose of m
taining a current remains to he proved.

" Mr. Benson's boiler may perhaps be regarded as the best of
a class of generators, in which tjje distinguishing principle is the
forcing of water through a continuous coil of tube of small dia-
meter, exposed in whole, or in part, to the action of a fiimace:
From various causes these bnileie have never met with extendeil

" Dr. Alban's may be regarded as the type of a far aup«ior
class of generator, in which a large flat vessel, with the aides ve^
heavily stayed together, usually called the ' heart,' is mode the
means of communication between a very large number of tubes,
about 4 in. in diameter, and 6 or 8 ft, long; one end of each of
these tubes is firmly fixed in the front plate of the heart, which
stands just over the fire <loor. The tubes traverse horizontally a
^re apace aoate 6 01 8 ft. high, buoltoE \>n&VoQ.^t!LI««i«^^H^ib^

EoiLERB.] HIGH niESSDRE BOILERS. 71

heart formirg the fourth. All the tuboa are sot on a sliglit in- .
t^tine from the heart downwards, so that the ^team may, h; its
'"•wii levity, rise towards and enter the heart, while the water, by
its gravity, flowB into the tubes to replace that evaporated. The
ends of the tubes furthest away from the heart are stopped by
moveable cuverSj which can be removed to clean the tubes, as at
lliia end tliey pass through the hrick wall of the tire-space, in
order that they may expand freeiy. A simple arrangement of
plates in the heart conveys the ateam, as soon as it leaves the
tubes, to one side, where rising, it passes through a suitable tube
into a separator about 12 is. in diameter, and some feet long,
placed horizontally on top of the generator, but not exposed to
the action of the fire ; the wat«r which rises with the steam flows
back from this separator through a second pipe, which descends
at the other side of the heart, and rising from it re-entere the
tul>ee, and is in part converted into steam as before. This boiler,
though very expensive, is an extremely durable and economical
generator of steam, from 100 lb. to 300 lb. on the square inch ;
and the tubes being the weakest part of it, an explosion never
leads to any dangerous results, from the reasons already pointed
' lut. It enjoys a very good reputation on the Continent, although,
we believe, never yet used in Great Britain.

" A class of boilers much the same in principle hut very differ-
ent in construction, has been gradually creeping into favour of
Ial« years. The dlEtingiiishing characteristics of this generator
are an outside shell, square, oblong, or circular, in horizontal sec-
tion, according to circumstances, which has a second shell, or
fire-box, about 6 in. smaller, placed within it, mnch as the inside
fire-boK is fitted in a locomotive. In the bottom of the inside
box, which is heavily stayed to the outside shell, is placed the
firegrate:, while the upper part is traversed by a namber of small
tubes feruled into the inside shell at each end; the flame and
heated air pass upwards between these tubes to the chimney,
which is usually placed directly alwive.

" This kind of boiler, although cheap, possesses many disad-
vantages ; it is very heavy ; it is impossible to clean the tubes
without taking out the whole inside box ; it is very difficult to
keep the tubes tight at the ends; and as it is frequently constructed
without any regard to correct principles, it has in addition been

72 ENGINEERING t'ACTS. [Div

accused of exceasive priming, wliicli is likely enough wLtn w
cunsider that the tubes are liot only very small, but put ii
dead level, so that a constoat coutentiou goes on between tli'
water and the steam — une struggling to get out, the otha
to get ia The tubes should always be put in on an incliii
of at least 1 inch to the foot, when the steam will escap
quietly frum the highest end, while the water will enter quietl;
at the lowest; a constant circulation is thus kept up, which no
only permits the supply of dry steam to the engine, but conduc
materially to the durability of the boiler.

" Whether a boiler can be produced which will permit t
u^ of sea water under high pressures, is a question we na
scarcely enter on; the success which has attended the introdnc
tion of surface condensation rendering such a boiler needleaa
Stillcertain mechanical difficulties stand in the way of the g
adoption of tuhulons boilers on board ship; one of the most im<
portant is the difficulty of obtaining room eimugh for the intro
duction of a new tube in case of accident. Tliis difficulty ii
experieuced when introducing an ordinary Hue-tube, because sucl
tubes invariably present their ends to the firing space, whidt ii
usually 8 ft. or 1 ft. wide ; but, owing to difficulties entailed b
the position of the uptake, the tubes, when horizontal, must almo^
unavoidably run parallel with the firing space when the stoke
hole bulk-heads preclude the withdrawal or replacement of the
tubes ; another, and still more serious objection, is the great height
of boiler necessary when tubes i in. in diameter are employed.
Unfortunately, when of smaller size, they are never durable, being
very liable to boil diy for a few seconds, when of course they
become overheated, and again cooled down by the rush of the re-
entrant water; they ore thus soon burned out; lai^e tubes always
' steam quietly,' and are found durable enough. In consequence
of these difficulties, many boUers have been introduced from time ti
time, in which the steam and water are contained in a large numtec
of flat-sided vertical spaces, well stayed, and arranged like books oi
a shel^ spaces being provided between them for the circulation,
of the flame and heated air. Such boilers are all mO'
complicated, heavy, and expensive j and although the principle ia
good, it still requires much improvement before it ca '
^Aiered worthy oi general adoption. M,amia \wi«» wiX

STEEL-CONSTRUCTED COlLEltS.

w

^Hrt tubes have met with much favour in Aumtica, and seem
^^ deserve tlie good character they bear, Althongli hori/i>Ltal
aarfaces are invariably the most economical, yet the practical exi-
gtoioies of marine boiler conatroction often dictate a recourse t-o
"Vertical surfaces as moat convenient"

For steel as a material for steam boilers the foUowing advan-
tages are claimed. That the same strength con be obtained with
loss material, and therefore thinner plates. The burning m
waating action of the fire upon tliiii. plates is less than upon thick
plates. Tiiat the conducting powers of steel ooiiaeqiieiit upon
the thin plates is greater than iron; and, therefore, a larger pinj-
portion of water is evaporated per lb. fuel. Our experience of iron
tells us that thin plates stand the action of fire much better than
tliick plates, this being especially borne out by American practice;
:uid therefore steel wilt be pre-eminently superior in this respect,
' liile it embodies equal strength with the tliick iron plates.

In Prussia the particular boiler experimented upon is of the
. ijLinon e^-end shape, without flues; it in 4 Prussian feet in
ifiameter, and is 30 ft, long, inclusive of the spherical ends.
There is a steam dome on the boiler, 3 ft in diameter and 2 it
high, as also a man-hole, 15 iu. in diameter and 10 in. high.
The thickness of the plate ia one quarter of an inch thick.
There ia another boiler built in, parallel to the first une ; it is
(ixactly similar in eveiy respect, except that the material of which
it is maile is simply common iron plate, the thickness of which
is 0'414 in. Prussian. Each of the boilers works up to a pres-
sure of 65 lb. The cast-steel boiler, however, was auecesaively
tried, by means of the hydraulic test, up to pressures of 98 lb.,
130 lb,, and at last up to 19S lb., without changing its shape in
the least degree, and without showing any leakages. The only
exception to this was, that two of the rivets slightly " sweated "
under the great pressure of thirteen atmospheres, or 196 Ih.
After both the boilers were fired in a similar way, day and night,
li>r about six months and a half, and at a pressure of 3^ to 3}
atmospheres, they were carefully examined, the steel boiler more
Kfpecially, during the Whitsuntide holidays, while the works
were standing. It was then seen that the cast-ateel platea vieiti
i[iiite aaaSected, oven at the places most imdiit tlie iiAaeocft cS.
^e.£r^ ^'^^fe appeamd, on examiiiatiou, a te-markatiV^ Bva^

,

^\^

p

I

I

I

74 ENGINEERING FACTS. [Dtv. U

amount of iucrostation in the ca8t-I^tl;el boiler, as compared witb
tbe boiler of common plate. Thia waa ascribed to the fact tliat
the eteel boiler generated 26 per cent, more steam than one of
common plat& It Lad been previously noticed, while the boilers
were working, that the relative qnaatitiea of water changed into
steam, in the steel and iron boiler respectively, were as 6 to 4.
The impression produced by the above esamination waa strength-
eni?d after the boiler had been in use for a year and a hal£ At
tills subsequent examination, made only very lately, the plates,
rivets, and the steam-tight qualities of the cast^steel boiler wera'
in a perfect state, and it did not appear that the least injury had
been caused by the fire to the plates more immediately under ita
influence. The small production of incrustation was confirmed
every time the boiler was cleaned; while the incrustation was J'
of an inch thick in al! the other iron boilers of these work% it
waa scarcely noticeable in the boiler of cast-steel.

During the recent examination, the quantities of feed water
were carefully measured by means of Gifiahi's injector, and the
average of twenty days' work, of twelve hours each, gave tha'
quantity of water converted into steam by the cast-steel boiler as
equal to 13992 cubic feet, and by the ordinary iron plate boUeF
112'44 enbic feet. The cast-steel bijiler thus evaporates ll"6fi
cubic feet per hour, while the boiler of common plate only steanu
off 9 '37 cubic feet of water per hour. The ratio of the two
above numbers (124'44 to 100) is thus almost exactly equal to
the ratio of 5 to 4 obtained in the first experiments. During
the same time, the quantity of coal consumed waa on an avert^ft
— for the steel boiler, 2,706 lbs.; and for the iron boiler, 2,772
Ite., for twelve hours; thus with 1 lb. of coal 3'28 lbs. of water ;
were converted into steam in the ateel boiler, and only 2-61 lb._^
of water in the iron boiler. The steam-generating capabilitiea
of the two boilers were thus as 127*49 to 100. The ateaniing
power of the steel boiler being thereby no less than 28 per cent.
higher than that of the other. It must be remarked that tbs
amount of water we have referred to one pound of coal does not
represent the absolute, but rather the strictly comparative evapo-
rating powers of the two boilers, because these boilers
Srvd directly, init by means of the waste gases of some puddling
iaraaoea olose.hy. It is also stated t.\uJ;, iu a^N^nlk >jCatst'

s.] STATIONAItV STEAM ENOISES.

i plates, and that these haTe lusted as long i

B the previons iron plates were often bunil out within

DI\1SI0N SECOND

STEAM-ENGINES.

10^^^

application of steam-engines as generators of mol

' from the expansive force of steam, has, owjiig to tlie

y diflerent nature of their employment, of necessity Uere-

i many different forms of engines, which are daily extemJing

paselves. Our space will not allow us to proceed to the

mderation of every different class of steam-engines, cor would

it all interest our readers, whom, we presume, are well versed

I such rudimentary matter. We wUl, however, classify this

division as follows ; — Section first, Engines applied to propei

ilationary maddnert/. Sewind, Locomotive and traction engiiiea.

"bird. Marine engines, or those applied for the propuUion of

AET ENCINE8.

n many are still made at a great first cost, but with a view to
late economy in consumption of steam and consequently nf
Nearly all such engines are condensing ; some of the old
[Fatt" type, hut those of later manufacture are chiefly upon
p combined high and low pressure or "M'Nanght'' principle.
\ those engines constructed on the latter principle, the high-
preasure cylinder is placed intermediately between the luw-ptessure
cylinder {which occupies its original position at the extieniity of
tfaa beam) and the main centre, either next the low-pressure
^Bnder or next the crank shaft. The high-pressure cylinder of
^^HBsity has a shorter stroke, and is made of a diameter con-
^Kbah}^ Jeaa than the iow-preasura cylinder — accoiita^ WC\.va

I

78 ENGINEERING FACTS. [Div.

iuitial boiler prassui'e. The steani is usually " cut off" by eithe
n expansion valve, or, more commonly in the " Lancashire com
pound engine," by the "double beat" equilibrium valve. This
ixpanaion, however, is in only very few instancea variable
to adjust the "cut off" to the work being performed.

ir, in Lancashire is little required, owing to the eteadinea
"with which the cotton machinery is kept at work. In othet
worka, however, this is not alwaya the case, and therefore a g
variable espansion valve iu communication with the {
would give still better results. The piston speeds of engines a
the above-mentioned class are very slow, and consequently e
engines are massive and proportionately expensive for a p
power. In America they have shown that it is not impraeti
cable to obtain a speed of piston in beam engines equal to S0(
feet per minute. We extract the following from the " SeienHJb
Jm-Wcan," which will give an idea how far piston speed is cf
ill beam engines; —

" At one period of the science of steam engineering it wa
practice to fix the limit of the speed of the piston at so maaj
feet per minute ; and fpim this ami the other data usually ti '
into account — aa the area of the piston, pressure of steam, &c
— the horse-power of the engine was calculated. If wi
in error, 250 fL has been set down as a standard s
pistons; but modern engineers prefer to drive their p
fast as they can with safety, and to disregard rules which expert
ence proves the usolessness o£ We have, as a result, the per^
formance of the engine of the ' Groldcn City ' (a new steamet be-
longing to the Pacific Mail Steamship Company). It is of tha
beam variety, the beam weighing upwards of 18 tons. This
engine has a piston 105 in. in diameter by 12 ft. stroke, and!
upon a recent engineers' trial trip, achieved the remarkable speec
of 430 ft., or (7^ double strokes per minute. We have no
iluabt that the engine will be able to add materially to thi>
speed, OS the machinery waa entirely new, it being merely a
perimental trip. This is not an isolated ease, by any means
The 'City of Buffalo,' formerly a passenger steamet upon Laki
Erie, now dismantled for the want of trade, had an engine witl
a cj'lindeT of 76 in. diameter and 12 ft. stroke, which drova
iddle-wheela 54 ft. in diamotei, vj^u^ee &^U\uwi^\i&.^

] PISTON SPEEDS OF BEAM ENGIS13.

ig, and had from 36 in. to 40 in. dip — 19^ ll
ihh, or 39 single etrokm per minute. By a aevvK e
intitbeniatical knowledge, we ascertain this to be a piston
1 of 468 ft. per minute. We remcmbet these faute and
a very well, as at that time we were pretty much occupied
g after the engine aforesaid. The beam weighed nearly
and was stopped and started 39 times in a minute,
^ with great ease and certainty. The beam of a beam
. appears to some to be an insnperafale obstacle to the
1 adoption of the class of engines to which it belongs ; ami
t, momentnm, velocity, &c, are charged heavily to its
merit. These theories, we fancy, are disturbed by the actual
facts in the case, which are, that the beam is so poised and
balanced on its centre, that the supposed shock of changing its
line of motion is utterly neutralized ; and as for the weight, that
~ .'Hipported by the filming, and is no more against the power
.'.erted by the piston than the smoke stack. A beam, weigb-
iij; 15 tons, or 18 tons, can be moved through any portion of
its arc of vibiation by the strength of a man ; providing, of
course, that tlie binders of the pillow blocks are not screwed up,
and that tbe jonmala sit fairly on the brass. The above-cited
cases of the speed of beam-engine pistons are all distanced by
tbe extraordinary performance of the 'C. Vanderbill,' a Soiind
'teamer, in her race, June, 1847. This engine is of 65 in.
c)'linder and 12 ft. stroke, and on the occasion mentioned, at^
teined to 540 fL, or 23^ double strokes per minute. It is not at
all uncommon or extraordinary to obtain a piston speed in beum
engines of 400 ft. per minute in this country, but the perform-
ance of tbe ' Golden City,' we think, is the best on record, con-
sidering tbe size of the cylinder.

■' Since writing the above, we have ascertained that all the
t'jcls just mentioned are below the mark. The ' Mississippi.' a
I irire paddle steamer, having an 81 in. cylinder and 12 ft, strnke,
'. 1^ made 24 revolutions per minute, ttie wheels having 36 in.
lip, and attaining a piston speed of 676 ft. per minute. The
Metropolis,' a large Sound steamer, having a cylinder of lOS
in. diameter and 12 ft. stroke, has made 20 revolutions per
minnte, and we think a higher number. The working beam o
'WsBi$sippi' weighs 14 tons; that i " "'

I

I

78 ENGINEERING FACTS. tDii

about 16 tons. The engine of tlie 'Now Worlil,' a, side-nhe^
steamboat 420 fL long, on tLe Hudson river, Laving a.
cylindBr, and 15 ft. stroke, has made 20 revolutions per minnlA
or fiO single atrokea. The ' Richard Stockton,' however,

outstripped tlie whole fleet, and, we think, attained the liigheal

piston speed fur an engine of this class ever made in tlte vrorld
We do not know the exact dimensions of the cylinder, but hart
been told it is between 50 and 60 in., with 10 ft. stroke. "'
' Stockton ' has feathering wheels, and makes 33 revolutions, i>
64 single strokes per minute; and has done this duty for yeara;
having beeu built by Robert L. Stevens for the espress objeo
of testing the speed at wliich a piston could safely travel "

ia the highest speed within our knowledge ever attained by i
piston in an engine of similar size ; if any other instances c
to mind we shall place them on record. It would be difficult b
point out any other class of marine engine of the san
that in the 'Golden City,' which could achieve 17^ turns i
minute, and keep it up as a regular duty. The standard of 25Q
ft, per minute will have to be changed, and made to suit modem
pistons, as the engines themselves stubbornly refused to be c
trolled by any such snuil-iike movement."

Beaia- engines at best are massive and expensive forme (
steam motors, and even taking into consideration their economjr
yet when first cost, expense of foundations, supplying water &
injection, and other accessories of such an engine are conaideie^
we doubt whether this economy will prove so prominently high
The most advantageous appHcation of the beam-engine ia that
used for pumping. Few engines, of whatever form, have beeQ
ahle to compete with the Cornish beam-engines in obtaining «
similarly useful effect produced from a given quantity of flieL

The beams of such engines now under consideration 1
hitherto been made of cast-iroa ; but the melancholy aocideul
at the "Hartley pit" has had a most decided tendency to am
vince engineers of the importance of placing little confidence i
the treacherous nature of cast-iron for such purposes, and (
adopting in its place vn«ught-iron plate beams, which are it
every respect superior. Of this tlreudful accident, the fullowf
is an extract from a practical investigation of the cause c

Srciu EsQiNES,] MODEL OF lEON BEAM. 7;»

such a disaatrouB occurrence from the " Practical Mecftanirs'
Journal:" —

"At NewcaBtle, at the exhibition of objectB of scientific ur
other interest or novelty, produced at the Central Exchange
^■^n riiig the British Association's meeting — an exhibition whose
■Hnscter we may say in passing was highly creditable to Nor-
H|piimber]and in every way — a model v/as shown by Messra.
K^okwy and Co. (37i), of a malleable iron beam for colliery
piimpinf; engines. It was a well-devised box girder beam, con-
sisting of two vertical aides iiounded by elliptical curvea at top
and bottom, and connected by a flat web plate all round, divided
by diphragms at various points, and provided with the requisite
bosses, &a, for the several gudgeons or axes of the beam and of
the parts of the eni^ne. The joints, &c, being nil double lapped
and double riveted. No doubt; as good a structure probably as
could be put together of boiler pJato, so far as could be judged
from a model only to a small scale; but we submit tliat this
does not decide the question whether wrought iron, in any form,
bo upon the whole preferable to cast iron, applied in the best
manner, for such engine beams; and if so, whether boiler plate
"'ork in any form he the best possible mode of applying wrought
Hvu, whether it may not have itself, however convenient and
i-lieap in formation, some apecial disadvantages; whether some
ir better form of wrought-iron work might not be conceivable;
iiid finally, whether some material, such as steel, might not he
oii^ierior to both cast and wrought iron.

I" We may not be able to enter upon all these points, and
indeed might not be able to settle them ; but preliminary to all
other qaestiona of the sort, it has always appeared to us that it
.ii;,'ht to have been settled in the most scientific, positive, and
'iiiaiislralive manner, how, and in precisely what way the
f 1 ii'tley beam (tliat originated by its fracture this proposed change
t material) gave way — that is to say, that it was all-important
I have discovered at the time of that accident, by the clearest
■liin of circiunstantiat evidence available, how tlie fracture oa-
'.:-i-ed, and to have sealed the truth of the conclttsion come to,
- tri the immediate cause, by demoitstrating, upon rigid principles,
''/•it the TTiotiont and forces eu concluded upon, wei-e /aiiffitient la
■ '■improdueed the effer.t attributed to them. /

ENGISEEKING FACTS, [Div.

^B "Thi.^ it appears to ua, has never yet bowi done. The evi-

^H dence given at the coroner's inquent had the iieual amount of

^V looseness and inGonclusivenesa, and at any rate, throughout it (aa

^V repuTted) no attempt to demonstrate, upon mechanical principles,

the precise train of foreea that caused the fracture, is to be found.

" The official report made to Sir George Grey, Secretary of

State for the Home Department, by Mr. J. Kenyon Blackwell,

one of the Government Inspectors of Mines— a clear and abl«

» document upon the whole — suggests, rather thnn affirraB, the traio
of causation that resulted in the fracture ; but the author does
not commit himself even to a clearly dogmatic afiinaation of the
cause, and makes no attempt whatever to demonattate,
chanical principles, whether what he suggests as having led to
the catastrophe, was adequate to produce the results he is to be
understood as having attributed to it.

I" This report of Mt. Blackwell's is, however, the most precise
and authentic document, we preaunie, before the world
subject of the Hartley beam breakage; and in view of
so grave as this, one in which 204 persons perished as
sequence, it certainly does not reflect much credit upon BritiBb
science, that an event so full of peril and agony of heart to many,
and firom which such lessons as should effectually avert a
rence ought to have been educed, has been suffered to pass hy
unimproved, beyond what may be extracted from the merely
suggested and nndemonatrated conclusion of the report we have
^ referred to.

^L " Let us very briefly refer to the facts. The engine beam which
^H broke was a douhle-flitched beam of cast iron of the form shown
^P in figs. 1 and 2. It was 34*.5 ft. long from centra to centre of

STEAV Ksfiises.] HARTLEV COLLIERY ENGINE. 81

liie end gudgeons ; it waa 8 ft. deep at the centre (acwrding to
Mr. Blackwell's rep-Tt), 8 ft 2 in. aa stated by Mr. Short at the
iui]ueet, and 8 ft. 7 in. aa given and figured in a (wntemporary
and usually well-informed journal In this ainguUr diacrepancj
upon so important a point, we mast accept the iirst aa the only
uutlientic etatemeut. Each flitch wub 4'T6 in. in thickneui,
exclusive of the metal of the riba and boss. They were pierced
with an hexagonal eye, for the centre gudgeon, the diameter from
side to aide of the hexagon being 1'75 ft., and this centre of
motion was 8 in. nearer to the end of the beam over the pit, thau
to the other at which the steam cylinder waa placed.

" The centre gudgeon was keyed in by laige rectangular keja,
driven (in pairs on each flat of the hexagon) by the eledge or
tup, and with great force. The engine was a double-acting one,
i.e., it condensed at both sides of the piston; its etnike was 10
ft., cylinder 66'5 in. diameter, steam in boiler 14 lbs. pressure
It had at a previous period worked at 4j strokes per minute,
but at the time of the accident was working Tj strokes per
minut«. We must presume it to have been regulated by a cataract,
as we cannot suppose continuous work at the velocity of 90 ft. a
minute, or even of 150 ft.; and, if so regulated, the velocity of
making the stroke will have been nearly the same in either case,
and then, the following passage in Mr. lilackwell's report is
diflBcult Ui comprehend ; — ' That liability to breakage existed in
this engine was proved by a former accident which occurred in
1858, when its gpeed was only 4 j strokes per minute, instead of
7^ strokes, as at the period of this accident.'

'' The engine worked three seta of pumps — two, one lower and
one upper, in the pit shaft, both hucket pumps, of 2 ft. diameter
working harrel, by 9 ft. 3 in. stroke. The dry spears were of
Memel timber, from 14 in. to 10 in, square. The bottom set
lifted the water 62 yards, to the other, which raised it 66 yards
ti> the high main ue«m.

" The third set of pumps were situated at the engine cylinder
end in ' a staple.' They were bucket pumps also, 2 ft. 6 in. work-
ing barrel, 6 ft. 3 in. stroke, worked from the engine beam be-
tween the cylinder and beam centres. There was a counter
beam and balance weight shackled on to the engine cross-head
above the i^Under, to bal&uce the whole sjBtem,fta svV<y*i\i \a SX\ife

r

83 ENGINEERINQ FACTS. [Div. IJ

litiiograplis {inblishuJ at the tiiiie by Lambert, of ^Newcastia
This is alao distinctly stated by Mr. Short, the engineer of t
colliery, at the inquest — ' the load of the engine ia balanced by ■
counter beam.' {Times, Fub. 6, 1862). But Mr. Blackwet
dues not mention this, and SEiya the balance was produced 1
' the smaller weight of the top set in. the staple, which was cooi
nected with the engine beam on the opposite side of its ci
of motion to the bottom and middle sets, was compensated by ths
difference in length of the two ends of the engine beam &om th^
centre of motion — the weight of the steam piston, the piatoq
rod, cross-head, and iron catcb-pin attached to the beam.'

" The preasore on the steam piston, by steam and vacuuu^
Mr. Blackweil says, was about 62 tons. The weight of the wd
and dry speare, buckets, and columns of water in the two sets o
pumps in the pit shaft (at the outer end of the beam) whea
the engine was about to make a stroke indoors, be slates ^
about 55 tons. Mr. Short, the engineer of the collieiy, stated nl
the inquest, that the weight of the engine beam itself vns
tons, and ' the total weight on the beam working both in f
out,' between 107 and 108 tons. He also stated, 'the weigbt
it had to lift, including the spears and the column of water, i
43 tons 18 cwt, and that the united weight of the engine pisi
and rod, and cross-head, was 11,536 lbs. — rather more than
t5na'{rmw, Feb. 6, 1862).

" There is a good deal of discrepancy here between partiet^
both of whom must be deemed authorities. It would appeo^
howevi^r, that the active load upon the beam was something be-
tween 108 and 117 tons, and that its passive load was iti
weight and those of its attached appendices in addition.

" The beam had been cast at the Walker Ironworks, and Mr,
AVarrence deposed that it was composed of ^ Blaenavon No, 3
cold blast iron, mixed with f No. 1 O.M.O. Scotch pig. I
also proved, we believe, to have been flasked, and not cast in
open sand, as stated by Mr. Hoskings, C.E., at the inquest, Tha
cast iron was examined at the School of Mines, Jermyn-stree^
and we are indebted to Dr. Percy for the following determination
mad* of the amount of injurious constituents jiresent in 100
jjarts of iron, and carbon, &q.

Fbosphona .... 11.1

FBACTUBE OF BEAM.

F

^■^ " The iron, ihefefore, was by no means bad in qnality. The

^^l^eam suddenly broke t^bt ttrougb tbe eye, tbe fracture running

I in the direction marked in the fig. by a dotted h"ne, and paaang

through the two diagonally opposite, nbarp re-entering angles of

the hexagonal eye— in this, as in every other case, showing that

^^ the fracture cboosea not the very weakeat measured tectum, which

^^Uhere would have been right across the beam, but the weakest

^^nUce, section and quality of material token together, Here

^^pUirongh these angles, where " planes of weakness ' were indnced

I by the peculiar crystalline arrangement induced by the sharp

angles of the eye,

"The fracture showed no old crack, it was bright all over;
adherent ahreds of lorn out iron were remarked upon by one
witness as a proof of the toughnese of tbe metal; but no obser-
vation appears to have been made by any one with a view to de-
temdne which was the compressed and which the extended side
of the-beam at tbe time of fracture j whether by the position of
these shreds above or below the axis, or otherwise; a most si
giilar omission, when we bear in mind that the point most ii
portant to be determined in the first instance was, whether the
beam broke by a force acting &om below upwards at one end, or
by one acting in tbe reverse direction, t.e., whether by a c<
sion after the pump speara broke, or by a dead puU suddenly
arrested. The fracture also showed four great ' draws ' or hollows
left by the shrinkage of the metal as it consolidated. These
were at the sides of the central bosses, where the solidifying iron
^^^ remained last liquid in the mould.

^^L " Tbe pump speara in the pit shaft were both found broken,

^^^Mt. Conlson, the veteran master sinker of eighty-four coal-pits,

^^Huid whose voluntary and unremunerated exertions to relieve the

^^^huried men, along with those of his son and foreman, have made

their names justly renowned, deposed that the fracture was about

14 fathoms from hank, in the main spears, and opposite the

middle seam, i.e., about 60 yards lower in the other spears;

both lie and Mr. Short appear to intimate that the &acture

of the timber indicated a pull asunder end on, and not a cross

fntctum

I

I

H ENGIHEEBINQ FACTS. [Drv. 11.

" There appears some discrepftncy also aa to the quality of the
timber, some of the witnesses at the inquest stating that at the
fracture it was perfectly sound, an opinion that from persoual
oommunication we are aware is Mr. CouUon's also, Mr. Black-
well, however, states ' tlie wood in the bottom dry sx)ear neai
place where it parted was found to be not perfectly sound.'

" The engine piston, &c., had completed a down stroke after
the beam had broken, the cylinder end of the beam had come
down heavily upon the catches and spring beams, and the c
head or piston cap had been fractured. The pumps in
staple ' had nothing wrong with them.

" The outer end of the engine beam, on breaking oif, plunged
down the pit shaft, carrying the wooden brattice (which ran
and west, while the length way of the beam was north and
south) crashing down into the shaft before it, and blocking up
the latter with debris from the shaft lining, and the ruin of the
pit work generally, at about 138 yards from the hank, where all
were arrested by the oak buntous on which the middle set of
pumps rested. With these details, or with the terrible jiireum-
stanoes of the imprisonment of the men and the heroic efforte
made to release them, continued for long after they had been
released from all bodily suffering by the easy death of suffoca-
tion by ' the atythe,' we have nothing here to do.

" What we propose to consider, by the help of mechanics, how
far confidence may be placed in either of the solutions that have
been given of the precise train of forces that produced the
dent, and then to draw some- practical conclusions, amongst
others, as to the comparative advantages and disadvantages of
wrought-iron or other beams, as substitutes for cast-iron. ~
the mathematical treatment of the question, we are indebted to
our distinguished friend and contributor Professor Samuel
Haughton, Professor of Geology, and Fellow of Trinity College,
Dublin."

" The problem itself is a dynamic question of considerable
complexity, as is pretty evident from the fact that, bo far at
knowledge goes, not one of the many able colliery engineers
of the North, uo one, indeed, has ever attempted to grapple with
it, up to this date, when the accident itself is almost beginning
ta be fojgotten.

^■tKAM EN□l^-Es.} BEEAKIKG WEIGHT UF BEAM.

But &ia\, let OS set aside one or two of the popular v

tlie subject, as amongst those that, it ma; be pronounced with

certainty, could not pomhly account for the fracture. First, it

ca nnot have broken aimplj by statical overloading, long con-

^■kvied. A writer in The Engineer (Feb. 28, 1862) calculaU^

^^Hie statical strength of the beam from the common tbnnuta —

^V {BIl'— M'l 02B R > 4-5

the breaking weight, and upon the data following —

B ^ 8 inches ; D =; B8 inches, the full length of the line of fratliire ;

6 ^3-25 inehea; li = 86 inthea; buiI

L ^ 18 feet ; S ^ 296 lbs. for a bar of caEt-iron 1 inch aquaru ;

and amves at the conclaEion that the ultimate breaking weight
of the beam was = 976,7074 lbs., or about 436 tons; and

t calculating the greatest dead load upon the beam at 61,6414 '^
or under 29 tons, and deducting 10 per cent from tlie iirst value
1^ W for defective casting (i. e., the draw holes at the boseea),
k$ poutte out that the statical loail was no more than ^s^
m the breaking strain.
■ This is the smallest estimate that we have seen made in l^i[Tiree'.
H the pBsaive strength of the beam, and it undoubtedly under-
rated both the breaking weight and the load.

A more trustworthy calculation was given by Mr. Atkinson,
Government Inspector of Mines, in vol. 11 of the ' TranBactionis
i the Northern Mining Institute.'
\ From the formula —

5 W X RD= _
- ^ _\l.

■d upon the data that the statical breaking weight of a bar of
ind cast-iron 1 inch square, and 1 foot long, eitcaetre at one
^d, and loaded at the other, is = 606 Iba, reduced to 500, as
Qie beam was unsound at the bosses; and taking mfan values
for B and U, the line of fracture being S feet 2 inches deep, he
calculates the value of

W = HI3 8 3 18
But the statical load, or ' greatest steady strain,' he says, did not
exceej 106 tons 8 art, 3 i^rs^ 1 lb., acting at \S fefc\i li'Mi. 'Ovw _

ENGINEEKING FACTS. [Di

line of fracture, from wliich it follows that the greateat load was

only about j g.gg the ultimate strength. The two ratios, though

a indepandeut and different data, closely coincide.

Now, as it ia perfectly well known that, even under impulsive

r

^H strains, cast-iron may be ex]*osed to forces producing more than
^B one-fifth its ultimate extension, and lemain for decades of years
^ iminjureil, tJiere can be no hesitation in pronouncing that it is
physically impossible that the Hartley beam was broken hy the
long-continued action of ita steady load, even making every esti-
mate of allowance for the variable nature and alternation of that

In what follows, we shall find that Professor Haughton has
examined the question arising nut of one of the other suppositions
as to cause, namely, the possible strain that might have been
visited upon the beam by the fall it got iioia off the screw-jacks.
That view alone looked feasible, because it waa beyond the
reach of the judgment we form by tactile experience of such things ;
nq one could, by any analogy of experience, irat^ne what m^ht
be the atreas upon such a mass of 42 tons, dropping upon two
poins at its mid length, from even a few inches in hei^i

Let us come, then, to what we may call the authorized version
of the conditions that produced fracture. After describing the
engine, the beam, and the loads which he calculated were upon
it^ Mr. BlackwoU states — ' It appeared from the evidence of the
men being wound up in the shaft at the time of the ac<3dent,
that a breakage of the spears in the shaft, by which the etiffino
lost its load wholly or in part, did occur prior to the breakage
of the beam and the fall of its broken half into the pit;' 'and
that when this breakage of the apears did occur, the engine was
comnienciag its inside stroke.'

He proceeds — ' The resistance to the descent of the piston in
the steam cylinder being thus removed, the piston would be car-
ried downwards by the pressure of the steam on its upper surface,
augmented by the vacuum below, amounting to a force of abont
62 tons, and would rapidly acquire momentum in its descent
through a stroke of 10 feet in length, until both the piston and
J that end of the beam connected to it were suddenly arrested by
Iflie iron catch-pin, fixed upon the \jeam a\. \.\ia.t v^int, coming

Steam Esgines.1 FRACTUKE OF HARTLEY BEA^L gj

down upon the spring beame, where they were renJcreJ j)erfectly
rigid in their resistance hy vertical caat-iron columns benealh

■ The engine beam was of iron of fair qualily.' ' It was of
the full onlinary sectional dituensions of beams used in engines
of similar power.' ' The ovet-wedging of the beam centre may
kar>e contributed to render it more lialde to fracture,' but is 'not
alone sufGcient to account for the fracture.'

' 27ie breakage of tin beam must be atlrihuted to the violent
concusgion to which it was miiijeeted, when it, together with the
steam piston connected to it, were suddenly arrested, after de-
scending through a stroke of 10 feet, with the velocity acquired
under the pressure of the steam, by coming in contact with the
spring beams beneath, after the counterbalancing load in the shaft
was partially or wholJy lost'

" Such, in clear langm^e, is Mr. Blackwell's decision. Wu shall,
without fiirther preface, submit it to the calculus of Professor
Haughton. In the present section of these 'notes,' we cannot
do more than give the prehminary investigation made by that
gentleman, upon data supplied hy us, and not rigidly exact, and
which he desires shall be received as no more than a tii^ approxi-
mation to the problem of the Hartley beam. Upon mure pre-
cise data, as to loads and dimensions, form of the beam itself,
etc, since then obtained. Dr. Hatighton is stUl engaged with the
calculation, and we hope in a succeeding part to give fully his
exact determination of the strain possible to be produced by the
train of circumstances set forth by Mr. BlackweU. Meanwhile
the following calculations will show the methods employed, and
indicate the probable result of the final investigation."

tAPFBOXIMATB SOLUTION OF QUESTIONS RELATIVE TO THE FrAC-
THRB OF THE HARTLEY BeAH, BT ReV. SaHUEI. HaUGHTON,
FT.C.D., F.E.S.

Prop. I. — Problem.

A beam, of rhomhoidal shape, is euppoHed by an ams passing
through its centre, and loaded with equal weights at its extremi-
ties; it it required to find the tension and compression lo which
ittjMO-t* a

ENGINEERING FACTS.

^H 88

^V Let I denote half the total length of the beam,

^K Let d, its depth,

H Let t, its thickness;

^H Let W denote the weight of the beam,

^H and F, the weight suspeaded at each extremity.

^H The Mommit of rupture of the beam is equal to

■ (W + B P) ? .

and the Moment of resistance to rupture is

tf Ty dy :

where F deaotee the tension or compression per sq. in. at any
distance, y, from the axis of the beam, in its central vertical
gettioii (tig. 3). If C denote the tHOsion or corapressiou per aq.

in, at the top or bottom of this section, then, (assuming for the
present that the neutral axis passes through the centre of the
beam,) wo have, by Leibnitz' ])rinciple,

a EfiQiNBa.] FRACTURE OF ENGINE BEAMS,
refore, equating the momenta of rapture and refflatance^'ll

h eF)i

0'

bitegral must be token for the extended portion of the bbc-

fruni !/ = + ^toj/=Oj anil for the compressed portion

a t/ = - -~to y = 0;oT, since both extensioQ and compre*-

a are employed in resisting rupture, from y = + -toy = -~;

therefore

(W + B P) f _ C_3_£

ption of the beam,
riterefore, finally,

urtph 1, If the beam be 34 feet long, 8 feet deep, and 9^
a tiuck, weighing 43 tons, and be loaded with 300 tons lit
i the strain on each square inch of the top of the
J eentrol section —

+ 8 P) i = C a rf (2)

i sectional area of the central vertical

tample 2. If the beam be unloaded, find thi? sttairj per sq.

W^xample 3. If the maximum strain that cast-iron will bear,
m auddenlit applied, ho 2 tons per eq. in., calculate the forces, P,
suddenJy applied downwards to the extremities of tbe beam that
will just fracture its upper surface in the central section.
lu equation (2), \rnta C ~ 2, and solve tor P,

to ENGINEERING FACTS. [Dii

(12 + 6 P) 17 = 2 •! B12 X 8
711 + 102P = 11592

P = 138 tona .

Prop. II. — Problem.

If an unloaded rhomboidal beam fall on its hearing* through^
a Iteight, k, find the coefficient of atrain per sq. in. on the upperM
portion of the central section.

The mDmentum of each half of the beam, acquited in faUingl
through the height, li, is, (if V. be the velocity acquired).

tlie moment of which, with respect to the axis, must be equatedj
to the moment of resistance to rupture; therefore

iince V - V 2g k, this equation becomes

Tlie quantity y _ denoting the time of falling through k.

Example. If the dimensions of the beam be the same i
before, find the strain produced by falhng through 4 inches, i
Here, g must he expreesed in inches, and is equal to 386 inches ;
therefore

Vs

' 912 X 8 H
21 X 17

Km ■fcioijrra] rRAOTPHB tft "BNOWS B8AMA

Prop. III. — Pro blew.

fA rkomboidal beam, lifting pump tpeart at one end, and

\ed by the m/linder of a steam engine at the other etui, at

I commeneement of a stroke it guddenly alrained by att oh-

t catching the speare, which are broken aerou, ^ehet^ the

I beam if draten down by the piston of the engine., and

%motvm ie suddetdy slopped by a spring beam (supposed in

tide in position vritk the centre of pemaiion of the beam):

I the strain per sq. in. on the lower portion of the central

1 of the beam."

Itet a b, (fig. i), denote the position of the beam when thn

M^^^m

jpeare are broken, and a' U its position when its (notion is sud-
denly destroyed by the spring beam, O, and let a and a' be tho
angles made above and below the horizontal line by the centre
line of the beam in these two positious, i denoting the angle,
made in any position of the heani, with the horizon.

Then, if so be the angular velocity of the beam, hy well known
^^Mechanical principles, we have

^^k Am_ Statical Moment _ Flcait _

^^H <tt Moment of Inertiu 1

J P denoting the force of the piston drawing down the bearo, and
Tits moment of inertia, xnciuiling this force.

I

ENQISEERING FACTS.

^H whicb, b; integration between the limits B ~
^H becomes

I m

Tbe equation just written, i

multiplying botb aides by -

-')■

And, if A = i «m o, + I sin a', be the total vertical height thraugu
whidi the end of the beam descends before it strikes the epriog
beam —

or

1

^i- far

IB)

Now, it ia well known that the quantity of work stored up in t
body revolving round an axis, is equal to the quantity of work
stored up in one moving in a right line, with the velocity of the
centi-e of gyration, and having a mass equal to that of the whols
body revolving; or,

The Moment af Ruptum storad up is tlie beaiu = > I ;

and, since the engine beam strikes the spring beam in the centra
of percussion, the whole work stored up in the beam will be spent
in iracturing it, and none spent in a shock at the axle ; therefore,
aawehavebeforefoond the moment ofEesistance to rupture to bo

cad ,

c a rf

and, since I =
obtjiin, finally

.1

. VaT

i being the radiua of gyiation, i

« EsGisBB.] STREKOTH OF ESGINB BEAIIS. 93

3be thedi^onalaofarhombua,itsradiu3of gj-tnlinn,
to an axis, pasaiiig thmugli their interaectioDS, and
dicular to the plane of the rhombUB, can be proved to be

a the case of the engine beam,

(P + W)R' = WB" + PP;
e thus written, taking account of the weight, P,

, _ fl |/ F A [W (J 4

[ Example 1. Let P be 100 tons, and A eqnal to 8 ft. Find
in C.

, therefore, K = la-a ft.

Uang this value of E, in equation (7^ m

^ S X 16-a -/ lOOxl 42 X

'^eoso'^^^'™ =I'123 tonspersq. in.

a the preceding example, the beam of the engine is supposed

ided with a weight or force, P, at one end, and to carry no

d at the other. If we suppose a load at each end of the beatri

i V, the equation (7) must be changed into the following —

__(lR-/"2iP^T|y]Pj

I which E is determined by the equation

ENGINEERING FACTS.

EMimple 2. Let P be 62 tona, and P" be 20 tons, everything
1 ;„.- g before; then from equation (10) we find

iiyil..

I

I

I

= lilTo K ^"^^ = "'"^ of s 'on per aq. i„.

The preceding results are to be regarded as only a first approxi-
mation to the exact discussion of the important problem of thi
Hartley Engine Beam, which will require, for its solution, to have
taken into account the elliptical shape and eccentricity of the
beam, and the weights of the piston and condensing pumpn, and
the top lift of pumps in the staple, as well as the steam pressure^
and weight of the bottom and middle lifts and water.

In the preceding part of his inTestigation, Professor Hangh-
ton considered roughly, in Prop. III., the conditions of rupture of
an engine beam, suddenly stopped by a apring beam, r^rded as
an immovable obstacle, and supposed to be placed at the centra
of percussion of half the loaded beam. He desires here to correct
an error that has been printed in his solution.*

It is known, ajid will bo proved in the following pages, that
the whole of the work stored up in the half beam that strikes
the spring beam is destroyed by the shock, and passes into the
spring beam, in consequence of the latter being placed at the
centre of percussion of the half beam. Hence, in estimating the
moment of rupture (ai I), the inertia of the other half only of
the beam should have been computed. By some inadvertence
in the calculation, lu I has been computed for the whole beam,
instead of the half beam. The correction of this error wi"
iluoe the numerical values deduced from Prop. III. to half theit
amount, so that the insufficiency of the shock to break the beam
may be regarded as fully proved, if we accept the principle of

* Wb tiike thu blame of this quite upon ourBclvea. The MS. was iii
turned to 1)o examined by ua with the proofs, and through failure of time
bofoie going to presa, no proofs were rorwarded to ProfesBor Haughtoo, oud
so the error was not disooTored prior lo publicatioQi it ia one that does " ""
aSiet Hut juetltod employed in an; vay. — £d. Prod. UecKs. Jou/nuiL

Emgl-ikr.] STBENGTH OF ESGINK BEAMS. U

[tiatiiig tlie dynamical uioment of rapture to the atatioil luunieut

But this principle, however nsual, u in iteelf very uiifati«fac-
tory, because it requires ue to compiire a momentum with a weig/it,
^Bid nechanicianB are not yet agreed upon the conditions and n-
lictions within which such a comparison can be reganlMl as
^e to nature. Professor Haughton cnndders, however, that the
lethod he finally employs in solving the prublem of the Hartley
3 based on principles against which no such theoretical
tgection can be raised. The methoil of solution of the problem
mtaiiied in the following Propositions : —

A. There is first found the work stored up in the beam at
the instant of striking the spring beam.

B. The work left in the beam, after striking the spring
beam, is then determined.

C Tlie work of resistance of the cross section of the beam,
due to the extension and compression of its parts, is
also found, and there is then institated —
D. A comparison of the work left in the heani afttr the
shock on the spring beam, (B), with the work of re-
sistance, (C).
, Phop. a To Jind ihe rcork stm-ed up in ihe Hurlley beum at

e THOtngtit of gtrihiiig the spring beam.
\ The Hartley colliery beam may be regarded as an pllipse,
"" CISC centre of motion, A, fig. 5, of the subjoined engmvingg, is

Fig

lu outer c-iiJ, (Q), than its centre of figm
acted on by the following foroes. P. ihu
plus tlie wtig\it oS Y'^a\^u \iii, ^ft,',

ENGINEEBINR FACTS.

[Div. II

P", the weight of the dry rods ia the pumps of the top stapli
w, the weight of the uoloiided heam; Q, the weight of the;
broken speara of the pumps of the lower and middle lifts. Thft
beam, acted on by all these forces, moves from real until, thi
force P, having passed through 1 ft., the whole system impinges
upon the spring beam, b. It is required to find the work t
up in the beam. Let a, b, denote the Bemi-axee of the beam,
and let p, p', w, q, denote the distances of the points of applic
tion of the forces, P, V, "W, Q, from the axis of motion, fA) : it
A denote the height through which the force, p, descends, then
the

Work stored up in tlie beam = (Pp + Fp" + Wio — Qq)x — (1.)
Assuming as the data furnished —

P =70 tons = 62 + 8 j. = 18 ft.

P'= 8 „ p'^n „

W=49 ,, «i= I,,

Q = 19 ,, g =iei„

Suljstituting these values in equation (1), we find the

Prop. B. To find how much of the work stored up ii
beam at the moment of the »hoek, remained in it after the ihock.

To solve this problem, Professor Haughton discusses the fol-
lowing lemma: —

A beam, turning with an angular velocity (u) round a point
(A), fig. 6, fall^ upon the point, B ; it i» reqiiired to find the
angviar wlocity {oi) with wMdi it commences to revolve round (B).

Let a denote the horizontal distance of the centre of gravity
of the beam from the point A, and let / denote the distance of
B from A. The blow with which B strikes the beam may bo
represented by mv, where m denotes the mass of the beam, aad v
a certain veloaty to be found.

I 4f*«i't*(rr™.) KPFEOTB OP SffOCKS Oir BEAMS. 9:

^ig. 6

^Hlt foll-iws. froiii tliB wpll-kiiowii i)rmcii>l« i)f D'Aluinbeil, tint

^M m,./=.I (2.1

^^Bd that the shock on the beam at the axla (A) is

^B

^^^ft consequencQ of this shock, the beam commences to turn round

^^Be point, (B), with aii angular velocitf determini^d b.v the

^^Huatiou

^P m(^ — a)/=-T (4,1

" In these equatiou!!, I nrid I', deunte the momenta of inertia of
ihe beam, with resjjL'et to tlie points, A and B, Substituting
ilie value of e foiuid from (2) in equation (4), we find, after some
ti.'' I actions —

.•l- = m-(i'_a/l (5.1

-1 here A is the radius of gyration correapondiiig to the point A, or

^^<

if // dunote the eortesponding radius of gyration for the jjoint I
iting in (S), we obtain finally

(6.)

e angular velocity with wliicli the bcai
Ufvolve round 11

Now, to deduce from this lemma the quantity of work reniHin-
iug in the beam after tlie shuck, Pnifi'Bsor Hnughtiin miiki - use
iif the following well-known prineiple, aleo employLd in tin pre-
vious part of this inrestigatloB, viz.,

ENGINEERING FACTS.

[Dr>

The wai-k stored up in a revoliing body is equal to the tco
ttored up in a body of the mme weight mmiiiy in a riyht lit
ailh a tielaeity equal to that of the centra of gijratiuit.

Hence, the work remaioiDg in the beatu u

'-ir " '" ""*'■

Substituting iu this esprGssinn for u'^, ita value deduced from (
we liud

Work left in tha l.eaiii = j^ ^ ^

iince, by the same principle, the i)

ginal woi-k btoi'L'ti i

we find at length
Work left in the lieam =

work stored up originally. (J

In order to apply this result to the Hartley beam, it is .
sary to calculate k, A:', and o, and to know the Mnef, or liorix
oiital distance of the centre of motion &om the spring beam.

The square of the radius of gj'ration. A?, is found fram the fol
lowing equation ; —

(P4

= Pp»

py + w (ic'

(8.)

in which f denotes the radius of gyration of the unloaded beaia
round ita centre of figure or gravity. The other quantities have
been already given, and p is known from the expression for tin
" s of gyration of an ellipee, with respect to an axis pasein)

through ita e

uid perpendicular to its plai

, /3V 236

» H'hBweU'a Dyaaaiici, Pail 11., p. 21ft. CMnlituljjji, lS3i

Steam Engines.] CALCULATION IN STRENGTH OF BEAMS. W

we obtain

. 359-5
^ + tc* = —J- = 90 qu : />r.

Hence, we find

Fp* = 22680 )

Vp'* = 1056 ( __ .n -Qo

W(|»« + w«)= 37801 — ^'^^
Qq^ = 3267)

but P + F + W -4- Q = 132 tons, and tlierffoi-e e<iuati'ii

(8) gives

30783

In order to find ^^, we must use equation (8), substituting f<»r
Pi /^> w;> ^^^ Qt ^^® distances of the spring Ix^aiu from P, P, tlit^
centre of Ifce beam, and Q. Hence, since /=15 ft., the right
hand side of (8) becomes,

(P) 70 X 3« = 630 a

(F) 8 X 4« = 128

(356*25 . \ I )4(r><*
— ^ + (141)« j =42 X 292 12264 j ^' "'

(Q) 12 X (314)« = 11907 J

Hence, from (8) we find

24929
* • = 132- = 1«S'«

The distance of the centre of gravity from the centre of motion
is found by tlie equation

(P + F + W + Q) a = Pp + Py + W?r — ()q (9.)

or

182 a = <

+ 1260

+ 314 I" =^1^2(??<. 7>r.
— 198

or

"^2

a = -r^ = 9 ft. qu, pr.

132

Substituting the preceding values in equation (7), we find

k* — af=z 233-2 — 9 X 15 = 98 2

and finally

Work left in the beam after __ ( 98-2)* X 656-4 ft. tons , ,« ^^ .. .
the shock, — 233-2 X 188^8 = 143 77 It. tons.

ENGINEERING FACTS.

[Div. If

Prop. C, To find the work o/ i-esin/aiiee />/ Ihe Hartley cuh
I Ikry bmm due to the extension and eompreeeion of its parU.

Let A B, fig. 7, denote the poaition of the neutral axis of tin
1 beam a h, and let o (f denote the coeElicienta of extension anij
I compression at the points b and a, when the beam is on tlit
I point of breaking. If y be the distance of any element &otu th<
[ Eixis, we have

an equation which expresaea the fact that the sum of the foroM
of extenai'in is equal to that of the forces of compression,

Cft = C'S' .<11.)

1 the Report of tlu
Fig. 7.

Adopting the experimental results given
J CirmmUgwners oh Railway Structures,
(1849), p. 101, where it is stated that
the ratio of the ultimate compreseive
and tensile forceB deiluoed from thirty- ^
X experiments on cast iron, is 6'637 ; ^
or 17; 3 qii. pr.; Professor Haugh-
ton infers from this that the distance
of A B from 6, is to its distance from u
in the same proportion of 17 to 3.

Let lik denote the extension of any
element-ify of the beam, and let ds he
I the extension at the point b. Tlie force acting at dy l*ing de-
I noted by F, the work of estcnsiun

Work of e.

I End the work of compression is

f C M /■*' C (fa- J'

Work of ooiiipreHHioB, =^J F dr = — ^t~J -'* "» ^^ — H

HenCe, the total work nf it'si stance. 1joth of extension and
compression, is

w.) STRAINS CPON BEAMS.

h . If : -. dl : J^,

I it Pilaws fi-niu (11) tliut

Wurk of rcaistfluce, = -,-'l4 + b

Work of resielaoce, =s —: — x S; (12.)

B Jenoting the cross section in squite inches. It ap[>e«rs fnim
(tie experiments reconied in the Report already quoted, pp. 51,
53, 53, 55, thut the ultimate exteusile force of cust-iron is 701 4
U'ua, aiid that the exteusiou produced by this uUimut« furuu in

I— jth of the length of the har.
lutroduciug these values of C and rfs into equation (12), and
nieinbering that the Hartley beam was 34 feet l»ng, wc uhtiiiii
Mil
Itei
:.
T!
fo.

kiork of renBtsnce or Hartley )
■Keam ungiiie, |

S-23 ft. t

[ Peop. D. To compare the work left in the beam teUh the
wk Mscesfory for fracture,

I The work left in the beam after the shock is employed in
leforming the beam into a curve, with a point of contrary flexure,
s shown in fig 8, where n u' denotes the neutral axis, and ab a
neutral surface, iu which there is nuitJier extension uor oom-

The work expended between « and ab is that with whith wi;
are concerned, and the portion expended between ab and «*, is
employed iu tending to fruutiii'u tlio eiiginu heam uu the spriiij,'
_beani, b.

From A to B is 15 ft., and from A to w' is 19^ ft., from which
8 probable that hy far the greatest pwtiou of the work left in
e beam is spent on the portion between ab and n.
""" 6 work left in the beam was found to be 14377 ft. tonn.
6 work requisite to fracture the beam at A, upon the ibita
I, IB only 118'23 ft tons.

^therefore, ptuWIiVj ui a^'iaafc'

the powers of reaistaiice tif the nialeriiil, even d«duttiiif{ tho
expendffll ill tending to fracture Ilia beam at tlie point B,"

The preceding important inyeHtigaticin — which the ' Praetieal
Mechanics' Journai ' has done the engineering woi'Id good
. vice by publishing — although occupying a considerable portion
L of our apace, will be exceedingly useful to those interested
Vthe designing of such beams, as supplying important niatlie'
' matical data for ascertaining tlie precise sti'aius to wliicit audi
beams are aubjecteii

Bijara Hteam engines are not the only ones, howeveii
wliich have " compound " or high and low pressure oylitt-
iler% for of late years this system has been much introduced
o engines of a horizontal construction, and with the best re-
ts. Several cotton factories have had such engines lately
but down, eome having the high-pressure cylinder immediately
ind the low-pressure, the same pistou rod pacing through
}nth, and the power communicated to one crank. Others haTe

lid low pressure cyhiidera lyijig alongside ona
tlier, and the power communicated to cranks set diametricB]^
' e each other. In both instances the air-pump is wrOQ^n
4 Itiver, receiving its motion Irom tlie cross-hcad of {tti

HOltlZOSTAL COMPOUND ENGINES. 103

B of l]«rizunt«I Bomp-mnd etiginps ia that h«»iiig
\^ and low pressure cylindera laid, a* above, side liy side.
e omnhs i><-ing, instead of diatnetrically oppoeite, at riglil
" "■'Th U plan, tinwever, neceesitatea a receiver to contain
^^1 ef tlw high-presanre cylinder antil the low-pn»Btini
J Wftehed the end of its stroke. Messrs. "Waller, May,
f^nningham, exhibited in the late Iiiiematioiial E*-
r ADgine of this description. The receiver ur reser-
igbt-iroR, and jacketed with high -pressure eteaui
Such a plan as this tends to prodnce a steadier
B engine, but beyond this it has no advantnges. A
I, however, and very much eimilar to the above,
■■ Wenham, who also exhihited a portable engine
~i and low pressure cylinder, the ctanks being
t angles. In this case the ref^ervnir was placed in
e-box, and consisted simply of a round easing having
I tnbes coincident with those of the boiler j the exhaust
■ high-pressure cylinder was placed in commtuiieatioti
wit4j ttil9 superheater, aud the steam, in passing through it on
ifs way to the low-pressure cylinder, was recharged with a quan-
lity of heat, thus augmenting the pressure of steam, and prevent-
ing further condensation consequent upon its increase of volume
in tlie low-pressure cylinder. This we consider the beet airange-
nient of horizontal liigh and low pressure engine, for it is exactly
at this point that the steam, alter having been espande<l in the
high-pressure cylinder, requirea to be superheated, and the time
is just sufficient to accomplish this — namely, the time occupied
between the exhausting of the high-pressure cylinder and
the completion of the stroke of the low-pressure cylinder.
Such combined high and low pressure horiKontal engines
are rapidly tidring the place of the huge and elu^iiah beam-
engines, with equally good results in economy of fuel, wliile a
saving of 50 per cent, is effected in first cost. Much has of
late been argued in favour of the horizontal engine over that of
the beam, some recommending high speeds of piston, such as
1,000 feet per minute, and with a high degree of expansion. A
^ y good specimen of such an engine was exhibited in the late
ttemational Exhibition, called the "Allan " engina This engine
d » Jong stroke, aad was fitted with a pecuAiai expniaw^ ''■^^'■■'

r

I

lOi ENOINRERING FACTS. [Div Tl

whereby the "cut off" was varied by means of a. pair of exi
tremely sensitive governors, called the " Porter" governors,
engine was kept Fanning, at a speed of piston eij^ual to 800
per minute, with the utmost steadiness, " cntting off at II
per cent, of its stroka We onderstand the same engine ii
at constant work at Messrs. Easton, Amos, and Sous' i
running at a speed of piston equal to 6G0 feet per minuta
Numerous objections are made against horixonttd eiiginet, bi
practically they are not very valid. On tte snlnject i
comparison of such engines, we extract from the columns of tt
" Eiigineor" the foUovring article: —

" There is an unacconutable prejudice on the port of cottoq
spinners, com-millers, and brewers against horizontal stean
engines. This prejudice is derived from no experience, fl
gines of the kind in question have not been put upon anything
like a sufficient trial in cotton-mills, corn-mills, or breweries
Nor is the objection founded in reason, for the balance of fi
and argument is decidedly against beam engines. They t
heavy and costly, require costly foundations, aud occupy a great
deal of room, and for all this they present no compensating a'
vantages. In respect of weight, whicli is a tolerable index
cost, we may compare the nan -condensing beam engine exhibited
last year in the International Exhibition, by Messr& Mirlees anil
Tait, with a horizontal engine of the same jwwer, hy the sauiQ
makers, and intended for the same purpose, vit, driving a largv
sugar milL The beam engine had a 23 in. cylinder and a i ft
6 in, stroke, while the horizontal engine has a cylinder of the
same diameter, with a stroke of 4 ft., making a somewhat greater
number of revolutions with the same speed of piston and same
total power. In the case of the beam engine, the bed plata
weighed 7 tons 14 cwt., the six coluums 5 tons 2 cwi, and the
entablature 3 tons 5 cwt., making 16 tons 1 cwt. of framing.
Tlie bed pl.ite of the horizuntal engine weighs 4 tons 13 cwL, or
but little more than one-fourth as nmch, while its actual stability
is even then greater than that of the other arrangement of fram-
ing. The working beam of the beam engine weighed 2 tons S
cwt, the whole of which is saved in the horizontal engine. The
cylinder of the beam engine being supported upon its end, i
bt'/iiQ also, 6 in, longer, weighed IT owl. mote than that of thq

S-] COMPAWSON OF EKOI.VEg.

ms

mUi, which, witJi coven, weigha I tun 13 cwt, TLe 30 It.

i-wheel of the boriKontol eugine weighs 9 tons, tliat of tiie

a engine, working slower, weighing 13^ tuiis, liltliougb wu

mot chaise any diifetence in tlija respect to the mere amngo-

The whole weight of the beam engine was 44 tons 9

, while that of the horizontal engine is leas than 20 tong.

B excess of weight fairly attributable to the beam arrange-

kit may be set down as at least 15 tons, and the pmportioiiute

it may be pretty correctly iiiforrt'd from this diiference alone.

" I the space occupied would be chiefly one (if

Ight, which, ill this case, would not, perhaps, be of great con-

~wqnence. With a still larger single cylinder engine, the beam

would occupy from 2,000 to 4,000 cubic feet more space thuti

the horizontaL The difference in foundations ia also against thu

bea m. The supposed advantages of the beam engine are that

e cylinder and piston wear better, and that the parallel Diotton

J be mope conveniently applied, and thus economise power

rased to be wasted in friction on the guides of a hori?untal

, If there are any other advantages we are unaware of

^Examining the points of objection against the horizontal

ine, we will first consider the cylinder. In point of fact tlio

r is little, if any, greater than in the beam engine, and the

t of wear, instead of being at the bottom of the cylinder, as

pt of those who object to the arrangement conclude, in view

B weight of the piston, that it must be, is contiued almoat

tirely to the upper part of the cylinder. The side of a oylin-

r next to the ports is always somewhat softer than elsewhere,

■ring to the greater miLSs of metal there; the lubrication is not

I abundant at the top as at the bottom, and if the piston

tance to blow a little steam, the abrasion thereby caused in a

"(ontal cylinder will necessarily he on the upi>er side. A

l^linder of good metal is a long time, however, in wearing,

uitever may be its position, unless, of course, it is under the

if a careless engine-man. It is not, however, every kind

[-iron that will serve for a cylinder. Those of Messrs.

s engines are of Madeley-wood No. 3 iron, and several

%the locomotive makers have found an advantage in mixing a

lerate quantity of wrought-iron tiiminga with their pig metal,

t OJsuU htiiiii'au injD o/ great liardufra, \vVi\>i, es.CB^*iai\M:i

I

Ififl ENGINEEBING FACTS, [Drr. II.

lui't;*; cyliuilfits, tLa mixture will run very uniformly, TLe great
cylinders, from TO to 112 inches in diaineter, employed for scren
engines, wear very slowly indeed. In the horizontal engine the
piston is much more convenient of access, and the pocking is
likely, therefore, to be looked after with more care. When, too,
the cylinder does become worn, it may be ea^ly and quickly
bored anew without moving it from its bed, the portable boring:
apparatus now largely adopted in railway workshops being em-
ployed for that purpose. As for the parallel motion, that mighl
be easily enough applied to a horizontal as well us to a beam engine,,
and indeed a Wiltshire agricultural engineer has actually a^pted
radius rods for the horizontal piston-rods of portable engines. Wa
do not, however, approve of ' parallel ' motions. In the first plaC6i
the motion thus given to the piston-rod is not mathematically rec-
tilinear, aiid cannot poaaibly be made so. But, more than thj^i,
with the least inaccuracy Id original adjustment, or, what is mora
likely, that resulting from slight wear, the radius-roda throw ft
heavy strain upon the piston-rod. With a horizontal engine, it
the crank is made to turn in the proper direction, the pressnre of
tlie croBs-head is always upward upon the guides; and a« th«'
upward pressure due to the angularity of the connecting rod
not great, relatively, where the rod is long, its weight and that of
the cross-head tend materially to diminish the friction upon the
guidea. The mean inclination of the connecting rod to the guide*
should not, and need not, exceed 1 in 10 throughout the stiokSt
and the friction due to this pressure should not exceed, and pio*
bably would not be as much as, one-tenth of this pressure^
one-hundredth part of the actual steam pressure on the piabHi.,
This is without making allowance for the weight of the connecti^
rod and cross-head, which might diminish the upward preBsun
to angularity to an amount which would not probably iR-
Tolve a loss in friction of the guides amounting to one-half of 1
per cent, of the whole power of the engine. The whole frietiou,
liowever, upon the guides of a horizontal engine can hardly bo
much as that brought upon the crank-pin and main bearings of
a beam engine, in consequence of the wotse than useless stnuA'
exerted upon them, at every stroke, by the momentum of a heaVf
iiid rapidly vibrating beam. A moment's reflection must ahoi
' power in clianging the motion, sixty times a

la.] SPEED OF WORKIXU OF STEAM EN'OIS-P-t, lOr

A be&m maay feet in IcngtL, atid weighing sevcml loa& In-
id the presence of the beam prevents the uluption of tixni
A o! piston at which, all tbitjga tak«n into account, steaiii-
e work moBt economically. This renwfk applies, of C4>ur8e,
both beams and aide levers, the latter typifyiDg the worst fonii
D engine. It would be useless to consiiler the workitig of
u engine with 23-in. cjliiiiiets and 4 ft, stroko at 60 revi>-
IB per minute. The strain caused by patting the heani inti-
D and bnuging it abruptly to rest 120 times in a niinut«
i be very great. It is this impraoticHbility of rapidly vi-
g a heavy beam that has retained the old standard nf 220 ti.
[SO ft of piston per minute 60 long in use. B^^move the beam
nhe other parts of the engine are perfectly adapted to work at
B tliat speed, the heaviest engine in the navy working reg'i-
f and constantly at nearly 500 ft. per minute, while there is
n-nWy no difficulty in working at an even higher dpeed. It is
li'.n'uuee of the necessity for slow speeda imposed by the beuiu
thrit such absurdly heavy masses of machinery are to be found in
our cotton-mills, floui-ntills, aiid broweries, and sometimes, wi-
regret to say, in the factories of engineers who should know
better. Other things being eqnal, and provided only that the

I ply of steam is sufbcient, the same engine may exert 100 or
} actual horse-power, according as it may be driven at, we will
120 or 80 revolutions per minute, and conversely, a quick
Sting engine may give olf the same power as a slow moving
engine, and with a saving of from one-half to two-thirds of its
weight. Quick speeds require, at most, only a moderate exten-
siun of the bearing surfaces, the work in any case being sup-
1 to be carefully done,
J' That the preference for a heavy rather than a light job liaa
Bometliing to do with the recommendation of the beam
^ne by so njany constructing engineers we may reaaonably
ippose. ThiTe are other engineers, however, not less well-
infonned, nor less successful in the character of their work, who
]<i«fer horizontal engines, and are able to assign good and sufficient
reasons for their preference. As more generally constructcil,
there is no doubt that horizontal land engines have not hail t!ie
iwlvantage of the same workmanship which has been expended
u^ti btam enginesi and this circumstancA is \mio'E^MUD.^ % ^u.V

I

108 ENGINEERING FACTS. piv

iiig tn tke prejudice of the moat mecliaiiicul ommgement of tlia
Bteam-engiiie, instead of being interpreted, as it siiould be, t
tile disgrace of tlie workman. Excellence of material, deaign,
proportions, and ■workmanship should Le accorded alike to
beam and horizontal engines, and it wiU then soon appear that
the latter are the most deserving of preferencfe.

" Some of the principal Scotch paper-makers have adopted,
or are about to adopt, horizontal single-cylinder engines, and v
find that, with either one or two cylinders, horiKintel enginea a
slowly working their way into flour-mills. Even setting aside theii
great advantage in x>oiiit of flrst cost we are convinced that, wib'
firat-clasB workmanship, they will nltimately prove them«elve
auperior in every respect to beam engines."

The whole ai^ument, wb may here remark, on quick speed veiiru
alow speed engines may be simply summed up in a few questions.'
First, What constitutes the primary poweriasteam-engineal Clearly
it ia the evaporation of water, — in other words, the formation of
steam. It follows from this that the boiler is the true spurce at
power; and, therefore, the actual power obtained must always ds^
pend upon the capabilities of such a boiler for generating steanu
This capability, in its turn, depends upon the esact amount and a
rangement of beating surface, coupled with a proper proportion c
grate area. The boiler then ia the primary generation of power
in the shape of steam, tlie engine, simply a secondary machine
for the economio conversion of such power into work or mecbaui-
cal effect. '

Ifow the form and nature of this engine is merely a matter o
economy, in which many circumstances require consideration.
Primarily, we aim at economy of steam or heat, and consequently,
fueL According to " Joule " the theoretical equivalent of one
unit of heat (tliat amount which would raise one pound of watel
through one degree Fahr.) is equal to the work of raising 772
lbs. through a height of 1 foot^ Sow our very best enginea do
not realize more than 30 [ler cent, of this. Tliia points to serioua
defects aomewhere ; it shows us that we have a large proportion
of power escaping from the chimney or funnel of our boiler,
ftlflo points to the probability of our engines being conBtmcteii
ujuin a wrong principle, or, at least, not upon the beat principle.
TJie mast economical aud g>;neta\\3 aio^tfti tw^jue ia tlyi

mm

Stbam Engisbs.] speed OF WOKKIHG OF STEAM ENGINES. 109

constructed upon the reciprocating piston principle; but at best,
this of necessity wastes mnch power. Take, for instance, the cose
of a locomotive, whose piston-rods, cross-head, &c., weigh 1 uwt.
or more, tfais reciprocates through a course of S feet^ and performs
300 double strokes per mioute. In such a ca^e we have a mass
of material of 1 cwt. put in motion by the force of the steam, at
a speed of 800 feet per minute^ and brought suddenly to rest
again by the effects of a further quantity of steam, either in the
shape of a cushion from the exliaast and lead, or at the expense of
a hi'avy Btrain on the cranlt-pin. Now, in tliia alone we have
an insurmountable barrier, preventing us from obtaining anything
like economical results. A rotatory engine, theoretically speitk-
ing, is the best in principle, and is the only engine which will
give the best results; this, however, practically speaking, does
not yet exist, and it therefore remains for future skill and ia-
genaity to work out the problem of an efficient rotatory engine.

Ketuming, however, to the consideration of circumatances
which affect the natiire and form of the engine, we may say
that, besides the main object, namely, economy of fuel ; simpli-
city and durability of construction, as also economy in first coM
and space occupied by the machine, are also matters of great

Now this brings us directly to the subject before our notice,
an<l the ai^ument is a simple quo. Why should we put down
huge and costly engines with large cylinders and with a slfiw
speed of piston, when, practically, the very same eifect will be
obtained by an engine onc'third the size, but with a sp«ed ol
piston three times as great! 77ie same ammml of gleam mil hi
converted into mechanieal effect in the smaller engine as in the
larger, and with quite as economical results; it is, therefore,
nothing more or less than a waste of material and valuable space
to employ a large engine when we can get as mueh work from a

But amongst other objections against running engines at a high
speed, are the great wear and heating of journals; this, with
ordinary slow working engines, would no doubt be too much the
case, but that is the fauH of the journals and general construction.
Let the bearings of such an engine he in length from 2^ to 3
tioies the A\saneter at the shaft, and well fitted, at \'be tia,m% \\ta&
""fl Miie^ so as to give the shaft a gooi 'VfiWAim.

I

I
I

110 ENGINEERING FAQTB. (Div. II

bearing of aliout otio-thirj of tlie circumference, and no fear neei
bo entertained for such jonrnals heating at high speeds aa lung a
they continue to be lubricated. Such improvements as this wonli
inevitably take place, but for the prejudice of some ulJ-fiisbionei
makers, and that absurd and confusii^ term nominal hams p
ill view of wluuh many are misled iiitu the conception, ths
simply diameter of cylinder constitutes power; othei«, that it i
strake or pressure of steam ; and iu short, no two agreeing a# b
what really constitutes horse power. On the Buhject of such i
01' tiTins in engine construction the Meekanics' Maijcmne s»»ya^-

" There are few euhjeots on which more books have bee
wi'itten than the construction of the steam-engine. Tlio b
of tJte scientific truths involved ; the grace, so to speak, diapl&ye
in the movements of the finished machine j the fact of its b
to a great exttint, the basis of our whole social system, the aouro
not alone of our wealth, but of our luxuries, the spirit ministni
ing to all our necessities, could not fail to constitute it an a
tive object to scientific authors. By some it has been handle*
poetically; by some philosophically, scientifically, mathematically;
popularly; by very few, sensibly; and, in spite of the
printed matter whicli bears on the subject^ considerable dttficultj
is experienced in gathering any really useful information £rua
existing books. We need never be iu doubt, it is true, on n
matter connected with it, provided we are content to take o
taili guides, and trusting ourselves wholly in tjieir hands, p;
greas towards the residts to wliich they would lead us; but
our minds are unfortnnately so constituted that we cant
quietly submit to accept one guide, without inquiring into tlia
merits of others, we at once find ouraalves adrift, for each \
piisea to lead us to the same goal by roads differing widely ii
direction and smoothness. Such, perhajis, will alwaya be t'
case, and we regret it, for tne iact has proved more injurious ti
the steam-engine, and a more powerful cause of delay to its p
grass, than ignorance or direct prejudice on tlie part of the o
stnictive engineer ever conld have been,

" The assertion that the steam engine is, in one sense, 1

niost imperfect source of power we [iosseas, may be startling; little

reflection is requisite to prove it true. We can hardly be » " '

''' posaese any other mechaniwd sourca of motion, save faltii^

«ater. Animal strength and MOa ioroacSfta V«vi» tosi \

H0K8£ POWER OF ESalKtSL III

y Bseliil ntuler certain limitations, but they pU; b rery inftrriiir
L our manaiacturinK economy as cuui]jan^ witii nUir
b from tlie antiquity of the use of thia power, and from the
B simpUdly and invariable character of tbo latre on which
I energies depend, everything relating to it has become
roughly well knuwo ; and very little dillicalty ia experienced
lonstrucliug a water-wheel which will give foi-th a useful
it or modulus, eijnal to TO or 75 per ceuL of the thuorcticnl
X effect due to the CiU of which we avail ourselves.
Pin the steam-engine, on the ojntrary, we hud a nucliine
B entire succe^ depends on the accurate aciiiiaiutaiice of t)ii-
bneer, not only with lavrs scarcely jet well defined, but also
L the exact applicability to each or itny of them to cerbtiii
e and circumstances, which must always be exceptional, and
r with different engines. The question of Used rules for
I ateam-engine constructioa becomes as a consequence complicated
to the last degree, and presents difficulties sufficient, in our opin-
ion, to have long since bcmished them from anything preteniliDg
to be a sensible book. Tlie difficulty of practically carrying out
theoiy; our conipatative iguoraace of what theory really says
tnithlutly on the matter; the exigencies of diverse situations
into which the steam-engine has tu be fitted, as travellers wei*
on the bed of Procrustes — have all operated very effectually in
preventing its average of useful effect approaching even distantly
t>) the practical perfection of the water-wheel orturbiue. Instead
of 70 or 80 per cent., we realise about 30 per cent, of the power
due to the combustion of the coal consumed; in other words, we
bum three times as much coal as we ought.

" But one thing can set this great evil right ; for it is a great
evil, regard it as we may. Teach our engineers an accurahj
knowledge of the principles involved; but, for the ttake of pro
gress banish for ever llie collections uf arbitrary and dogmatical
rules with which the shelves of lur libraries, and our brains ar<«
equally biuiiened. We do not 'mean to assert for a moment thiit
c«rtain rales are not useful ; nay, we will go so far as to admit
thai, to a certain limited extent^ tbey may be absolutely indis-
pensable; but this can only be the cose when they are made use
of for the purpose of avoiding grave errors, not as being in them-
selves guides to success. Their proper function \a to ■gowA. onA

I

I

112 ENGINEERING FACTS. [Div. II

the course of construe tioii whicli is positively wrong, not tlin
whicli is absuluttily right. Their use ouca narrowed to thiif
their legitimate pruviuce, they become serviceable. la the pre
Bent state of tilings they are not only worthless, but to the L
degree miscbievous.

''The steam-engine differs from nearly all other niichines,
that ita aucceas depeuda, not on one, but a multitude of prin:
ciples, each to a certain extent demanding the obaorvance of eer
ttun rules of construction, most of which are incompatible o
with the other when the various principles are combined to fora
a whola !Not so, perhaps, provided we had infinite space i
which to erect our engines, but this not being the case, our asset
tion is in the main correct. Thus, a heating surface, as comparo
with grate surface, three times what it is now, would be ver^
advantageous provided it were attainable on board our steam
boats, but unfortunately it is not, because the principles
guide us in the construction of the niorine boiler must submit b
the inHuencQ of those which regulate the construction of a ship
To go further apart from what we may term external ageneiea
we find internal features and working necessities, which fro
quently lead to wide deviations from correct principlet^ whie"
may clash in their application to such an extent that each must
yield to the rest We might fill volumes with instances o'
kind, but they are so obvious as scarcely to need illustration a
our hands. We will point out one. On correct principles
water-heating, we should deprive the waste gases from a furii
of all excess of temperature above that of the water within the
boiler. So far bo good; but, on looking further, we discover
that to ensure rapid combustion, when that is necessary;
gases must possess a very much higher temperature in order that
they may ascend the stack with sufBcLeut velocity.

" In short, the more we go into the question, the g
find the difficulty of applying any fixed or arbitrary rules to the
steam-engine, the only machine which is commonly -employed
to supply motive power. T!ie water-wheel and the wind-mill
are iaatnunents depending for their success each on a simple
principle. The iitcam-engine derives ail its energy from manj;
dilferunt principles, which permit not only considerable latitnUs
i/idividaahy in their appUc&Uon, Wt, joaitivelY cannot be i

It Esoisix] POWEK or STEAM ESGIXES.

w

^Itfed in combtualion, \Titlioat, to a certain extent, Bacrifiuiiig
much that renders each most perfect. We ask, tben, how cnu

lixcd rules properly apply to a machine wimplicated in its form
an.i a hundred times more complex in its principles! Were it
possible to draw up a code of laws which would be applicabk to
erery varying circumstance, different form, and varying pnrpose
under which it is found, or to which it is apphed, they would
form a book so gigantic that it would be valaele^s ; no cue could
read it, none comprehend it. Even were such a book compiled,
and granted that it was absolutely perfect now in 1863, who
could say with certainty that it would be equally correct in 1873f
Tlie last ten years have ushered in wonderful changes, and we
feel little doubt that the coming ten years will produce results
equally important

" The engine of James "Watt bears little or no resemblance to
ihv engine of the present day. His was colossal, magnificent,
mighty in its appearance of power, The tardy giant certainly
i:i.itifetred blessings on the manufacturing world, such as no mo-
tive power which had gone before had ever done. But this giant
was costly to beep, slow in his movements, and his size anil
beauty formed but a useless pageant The condenser came to be
looked on as the most essential part of the engine — the source
of all its power. We, half a centuiy later, have learned that it
is but a useful adjunct, a means of realizing the last fraction of
economy, but not in any way necessary or indispensable to the
development of power from the combustion of fueL But all the
rules at present employed by steam-engine builders date back,
with scarce an eseeption, to the reign of Watt, and are, as far as
possible, forced into modern practice, whether applicable or not.
As well might we retain the old hemp-packed piston, as the exact
area of grate, or speed of piston, which the engineers of Watt's
day gave us.

" We may certainly apply eppirical rules to the construction
of a boiler, the speed of a piston, the height of a stack, &e. ; but,
«a bonof A different description of coals may render (
boiler next to useless; the speed of piston adjudged to ua may
entail heavy multiple gear — a difficult situation may render ex-
pedient the employment of an engine constructed apart from all
eudi riilea Of what avail, then, is it to print ani ^Mii\i^ ^a.'j.

I
I

m ENGINEERING PACTS. [Drv. 11,

after day, dogmas wliieh can bo of no general value, bei'am*
thoy are not capnbli, of general application 1 Why fix tbe speec
of a piston at 300 ft, per nunute when we find it do its duty
equally well at 100 ft aud 1 100 ft. per luiuute? "Why fij|
positively the area of a grate when a littln difference ii
of the air, in the quality uf the coals, in the skill of the lire
can alter the results obtained? Ij.it our engineers me aboAM
each narrow dogmatism ; let tliem bamlle the subject liberally,
let them study as carefully as tbey will the scientific truths m
votved in the worting of every separate part of the machine thej
propose to construct: let them display their talents in
bination of these different parta, gnided by an accurate and wait
trained perception of that coarse of construction most suitabh
to the circumstances in which they have to act, not blindly folj
lowing rules which alter not, like tlie laws of the 1 "
Persians."

The most improved and most economical engines now ii
duced are the combined high and low pressure engines, t
steam cylinder being wrougbt highly in expansioiL On t
merits of such engines a mast excellent paper was read beforo thi
Civil and Mechanical Engineers' Society, by Francis Campin, i
which the following is an abstract ; —

'■ The economical results accruing from tbe expansiye metho4
of using steam are now so universally known, that further argu-
ment upon the merits of that syfitem, except as to the degrea
wliich limits its practical utility, is needless; but I now desire
to direct your attention to the comparative merits of double snit
ningle cylinder expansive engines,

" The mode of employing steam eitpansively by tbe closjng o
the valve before the termination of the stroke of the piston, was
discovered by Watt in 1769, but he did not apply it until 177^
nor was it patented until 1782. The double-cylinder engine v
invented by Homblowerin 1781, and was subsequently combined
with Watt's condenser, by Woolfe. From these dates we find'
that the double- cylinder, or Woolfe 's engine, was invented very
soon after the advantoges of the expansive system were perceive*^
and down to the present time it has had numerous and importani
ailvocates; but, on the other hand, there are those who contemt
t/iat ihe present adoption oi\.\vi Woolfo engine is a retrograde steu

E

EsMHM.] HIGH AND LOW PRSasURE ENOINES.

P We find by searching amongst tbe patent reconla tlint evmi nl
tite present time the Woolfe engine is very highly esteemed by*
some engineers uf unduubteil experience and ability ; at leo^t euv)i
is the conclusion drawn from the numorons patented invenlions
by which it is endeavoured to render that engine more practi-
cally useful, and to approach more nearly to the theoretical
efficiency.

" Let us now examine the action of steam in the single-cylinder
engine and in the Woolfe engijie, it being supposed that the
st«am is allowed to expand to four times its initiaJ volume ; let ne
suppose our single cylinder has an area of 400 square incliee,
and that the steam has an initial pressure of 40 lb. per square
inch absolute pressure and the vacuum perfect ; the effect of
the steam in the passages being neglected at present ; during
the first quarter of the stroke the initial pressure will be main-
tained, after which it will gradually diminish to about 875 Ih.
jier square inch, giving an average pressure fur t!ie entire stroke
of about 2311 lb, per square inch, or 9'244 lb, avenge gross
pressure on the piatoii.

" The difference of pressure during the stroke is 31-26 lb. per
square inch, which is equal to 74'125 per cent, of the masimum

" We will now see how matters would be io a Woolfe's
engine under similar circumstances : let it consist of one small
cylinder of 100-in. area, and a larger one of 400-in. area. The
pressures are supposed to be as befora The effective pressure
iu the small cylinder will be 40 lb. per square inch minus the
mean back pressure; the back pressure of course varies from 40
lb. d.own to 8'75 lb, during the stroke, the average Iwing 17'485
lb., which, being deducted from 40 lb,, leaves 22'515 lb. per
square luch, or 2,251 '5 on the small piston. As the pressure
per square inch on the large piston varies frum 40 lb. to 8*76 lb,,
the mean effective pressure will there be 17*486 lb., making
6,994 lbs. on the whole piston. Hence we have for the mean
gross pressure on the two pistons 9,246*5 lb., nlniost exactly the
same as on the one piston in the last example, and as the differ-
ence is so minute (less than {cj^g), I shall take the two quan-
tities as equal.

■' In this case tbe mean pressure on the two \i«iflv» » \6'^5

ENGiNEERISG FACTS. [Div. I

lb, per square inch, nearly. The pressure on tbe small pLiton 8
•the beginning of the stroke is 40 lb. per sq^nare inob, with a
equal back pressure ; therefore, the effective pressure is nil at th4
ti)p of the stroke on the small piston. The effective pressure o
the large piston is 40 lb. per square inch at the top of the stroke
80 we may call it for the two pistons 32 lb. effective pressure pi
square inch. At the end of the stroke the effective presanre o
the small piston wiU be 40 Ih., minus 8'75 lb., equal to 31'2fl
'\ per square inch; that on the large piston will be 875 lb. pea
square inch, making the mean pressure on the two pistons eqnfti
to 13'35 lb. per square inch. The difference between the max.!'
n and minimum pressures will, therefore, he 31'25 lb,, mimii
13"2.'i Ih., equal to 18 tb. per square inch, or 67*6 per cent g
the maximum.

" It is, of course, taken for granted that both pistons act npoa
one shaft; then the method above adopted, of distributing theo-
ratieally the pressure over the gross area of the two pistons, give!
the same per-centage results as would he obtained by taking the
gross pressures on the two pistons instead of the pressure pe^
square inch.

" We thus find that the differences of steam pressure in tl
single and double cylinder engines, working at the degree of e.
pansion above mentioned, are, during one stroke, 74*125 per cent,
and 57*6 percent, of the maximum pressures respectively; henc^
"the Woolfe engine will work more steadily than the other, the
■variation of steam pressure being 22*29 per cent. less.

" Summarising the inferences drawn from the above calcula-
tions, we find :

" The single-cylinder engine is simplest and smallest, and the
Woolfe engine works most uniformly, and the cylinders are ex-
posed to least pressure in proportion to their diameters, '

" In the next place, it is necessary to notice the causes which
have hitherto militated against the general introduction of th&
Woolfe engine, and the obstacles to its practical success.

" As usually constructed, the double-cylinder engines have veiy
complex steam passages and valves, in which expansion of the
steam takes place without producing any useful effect. The loss
happens thus : when the vacuum is produced in the lai^ cylinder,
j't, o? ooume, extends itself to t\va steam ^aMagea as far a

II EsGisKfl.] HICH AND LOW PRESSUUE ENGINES.

soon as a communication is again made vf

small cylinder the eteam will espaiid and fill sucU passages, iherebj
heing reduced in pressure, and. therefore leas energetic in it«
action on the large piston than it would have been had those
passages between the valve and cylinder been absent. The
length of tliese passages will, of couise, depend upon the con-
struction of the engine, hut their cubic contents will generally be
I'ound large in proportion to that of the small, or high-pressure

'■Another disadvantage has consisted in the extra epHCe iv-
qmrc4 by the Woolfe engine, which amouats to that taken up
liy tlie small cylinder. This is evident from the fact that, «t the
euJ of the stroke, the wliole of the steam used is contained in
the large cylinder, and for equal balks and pressures this cylinder
must, therefore, be as large aa the one in the single-cylinder

" These appear to me to bo the chief objections to the WoolCe
engine; and that these may, to a great extent, he obviated by
meaDs of recent itiveiitioiis, I aball subsequently endeavour to
show,

" Having observed that the extra space required by the Woolfe
engine is exactly that occupied by the small cylinder, it follows
that this should be mode as smidl as possible in proportion to the
hirge cylinder J the size of the cylinder, as far as regards the apace
it oocnpiea, may be reduced in two ways— first, by using a, higher
di-gree of expansion; seoond, by altering the form, and position
of one or both cylinders.

" The limits of the first mode of reducing the comparative size
nf the small cylinder depend upon the pressure which it is safe
or convenient to use, and the size allowed for the large cylinder;
with regard to the second means of reducing the space occupied,
we may observe that numerous patents have been taken out for
arrangements in which the high-pressure cylinder is ao placed as
lo occupy what would otherwise be waste space; thus, in some
cases, the smaller cylinders are placed upon the top of the larger,
and connected by means of piston-rods with the piston of the
large cylinder through which the power is transmitted.

" I'he form of the cylindera is made anotheir Btibjeiit. <A \B.m\ja
patBotr/ tha^ it ia by one proposed to conatiucl l^e Wt^tcj-

ENGINEERING FACT3. [Div. II,

linder in annular form, ho us to surroand U;e smaller one, but
I tliid arrangement, as in others before alluded to, the Btsani pas-
I siigea between the cylinders mitst be lengthy, and this is a very
I great eviL

"Some time since Mr. Craddock constructed some Woolfb

E engines which worked with great economy j but I am inclined to

ink thnt for this he was rather indebted to his peculiar form ol

I boiler and the high pressure at which he worked his engines than

L to any particular superiority in the latter.

"It has recently been proposed to construct douhle-cjlindei

I engines so that the cranks of the shaft, which the pistons of the

1 two cylinders act upon, may be placed at rij,'ht angles to each'

I other, 80 aa to gain the advantages of the coupled engine in addi-

I lion to those of the double-cylinder engine; in this arra

I nieiit, however, it is evident that the piston of the high-preesoro

I cylinder mupit make a half return stroke after completing its

stroke before the steam cau he admitted to the low-pressoro

cylinder; and, in ordur to allow this, it becomes necessary to-

establish between the two cylinders a kind of r&^ivoir, lu whioti

the steam is stored until the low-pressure cylinder is ready

receive it, and from which it may also be drawn after the com-'

. mutiication with the high -press are cylinder has been closed.

L Let us now examine, relatively, the work done by a given

I amount of st«am in this and in an oidinary doable-cyliiid«c

I engine.

I " Let the small cylinder be 100 in. in sectional area, and the
I Urger 400 in. sectional area, the initial pressure of the steam
I being 40 lb. per square inch, then this will evidently expand
I down to 8'75 lb, per square inch during the stroke of the laigs
I piston. Let us determine the work done by one cylinder full
I of steam, the mean back pressure on the small piston will be
I 17'485 lb. per square inch, which, deducted from 40 lb., leaves
I 33'fi1S lb. per square inch effective pressure, making 2,3S1^ lb.
I pressure on the small piston, and taking the stroke aa 3 ft, tha
I work done in the small cylinder will he 4,603 lb. raised one foot
I Aa the pressure in the lai^ cylinder varies from 40 lb. per squara
I inch down to 8"75 lb., the me.in will be 17'485 lb. per squara<
I inch, giving 6.994 lb. pressure on the piston, and for the work
)doue in one stroke 13,988 Va. raiaed oim iuu^, «\^s^ mUad.

■■»■)

DOUBLE CYLINDEK ENGINES.

done in the small cyUader, makes a enm of 18,491 lb.

id one foot by one cjIinJer full of steain.

Now let U3 examine the caae of the double -cylinder engine

the cranks at right angles; let the dimensioiiR Hiid pressures

above, and let the reservoir he twice the size of the small

der. We must in the first place examine the variation of

ate in the reservoir ; at the termination of the stroke of the

pietun. it is evident the pressure in the reservoir will be thu

as in the large cylinder, viz., 8'T5 lb. per Bqilare inch. At

termination of the stroke of the small piston we have the

,der ftilt of steam at 40 !b., and the reservoir, twice the bulk

of the cyhndur, full of steam at 8'75 lb. per square inch.
Keuce, when a communication is opened between the small
cylinder and reservoir the pressure in the two vessels will be-
come 19 lb. per M)^uare inch; the smitU piston now begins to re
turn, compressing the steam in the reservoir till at half stroke,
when the pressure in the reservoir will be 225 lb. per sqaare
inch. The communication between the reservoir and lar^a
cjlinder will now be opened ami the large piston will begin to
move, the presaure fulling till, when the small piston is at the
end of its stroke and the large piston at mid-stroke, the pressure
becomea 13*S Ib.'per )iquai'c inch; the communication between
the reservoir and high-pressure cylinder being then closed, the
large piston finishes its stroke, the pressure behind it falling to
8'75 lb. per square inch, when the commuoication between the.
" [e cylinder and reservoir is closed, leaving the pressure in the
a as at the beginning of the stroke.
From these flgores we find that tlie mean effective pressurp
liston is about 20'62 lb. per square inch, making
3,062 lb. pressure on the piston, and 4,124 lb. raised one foot
each stroke. Similarly we find in the Ini'ge cylinder an efiective
pressure of I4'56 lb. per square inch, making a gross pressure of
5,824 lb. on the piston, and 11,648 lb. raised one foot per stroke;
then the sum of the work done per stroke in the two cylinders
will be 15,772 lb. raised one foot^

Comparing the two engines, we find that under the circum-
above- mentioned, the reservoir necessary in the double-
idCT engine with the cranks at light angles reduces the work
■^^fVB quaatitj o£ atenux fi'tnu 18,49\ W U> \^^'\'^

W70

^^ tb

r

I

120 ENGINEEHINO FACTS. [Dcv. 11,

lb. raised one foot, a loss of about 14'7 per cent. It may
here ba observed that there would of course be tbe same loss in
tliia engine compared with single- cylinder expanBiye engines,
so that the ordinary coupled engines, with cranks at right angles
would 1)Q far anperior to the above-mentioned form of Woolte'
engine.

" I have now to direct your attention to the improvement^
made in Woolfe'a engine by Mr, Syrett, whose enjjines appear
to be the most successful double- cylinder engines yet erectedi
In this form a longer stroke is given to the high-pressure piston
than to the low-pressure, so that the former has a greater velocitji
than the latter, when such can he done ; but the most importaol
part of the invention consists in the arrangement of the valve
which are so placed as to avoid the useless expansion of tlM
steam in the passages and steam chest.

amount of saving thus effected, taking in the one cose the ordi'
nary form, and in the other the improved construction, and sup*
pneing the engine to be of the same dimensions as in the last
example, the steam pressure being also

"The contents of the small cylinder will be 2,400 cnbio
inches, and the passages through which the steam would hava
to pass from the small to the large cylinder would contain about
1 20 cubic inches at least, and in this space there would of courss
be a vacuum at the moment of beginning to make a stroke.

" When the communication is made between the large antl
small cyhnder, the steam at once expands into the passages, a
the pressure is reduced from 40 lb. per square inch to 36 lb. pei
square inch, making a mean loss of 2 lb. per square inch prea-

i during the whole stroke, which is equal to Hi per a
of the mean effective pressure. If the valve is so arranged thai
the passage above-mentioned lays between the valve and th^
high-pressure cylinder, it will be filled with high-pressure s'
^_ when tht) small cylinder is filled, hy which an addition b> t
^L mean effective pressure in the lai^e cylinder will he made eqpa]
^H to about 1 per cent, which, added to the saving of 11'4 pel
^H cent., makes 13'4 per cent. ; from this, however, we must maka
^B a deduction for the extra steam required to iill the passaga,
^H When the stroke of the small piston is about to commence, tha
^K jmssage mil contain steam of 615 tti, ^rcessite ^ec aqiiare ii

I

^■b. Esc] D
Vn quantity

EsG.] LOCOMOTIVE AND OTHEK TRACTION ENGINES, HI

( qaantity of steam at 40 lb. reqnisite to fill lliia space will,
tliorafore, be about 96 cubic inches, or 4 per cent of llio ^uttntity
required for the whole stroke ; thus we linil that in Ihe present
case, even with the amoU paitsagea here supposed, the saving in
lliem alone by the improved method of construction ia 8'4 per
mal., and here I have ikot considered the saving effected it) the
steam cbest.

" Instead of going into further calculations regarding this en-
gine, it will be more satisfactory to quote an injatance of its ap-
phcation to practical purposes,

"In I860, the patent improvements were made upon an
engine driving a flour-mill at Halsteit, in Essex. It was a
single-cylinder engine, and, according to the proprietor's state-
ment, drove three pairs of stones, with a oonsnmption of 16 cwt.
of coal per diem; the cylinder was IS in. in diameter; two 6 in.
higfa-preasure cylinders were added, constructed as above-men-
tioned, and the engine waa then found capable of driving four
|iaii3 of millstones with a conaumptiou of only 12 civL of coal

DIVISION THIRD.
LOCOMOTIVES AND OTHER TILiCTJON ENGINES.

In this department of engineering, the march of improvement
fur the past year, or indeed for any one year, is comijaratively
snialL The ricli display of locomotives, however, in the Inter-
national Exhibition of 1861, showed many improvements, ami
established many important facts in connection with the locomo-
tive and its accessories. The moat prominent among these were
the extensive use of coal and conaeqnent apparatus for the con-
sumption of smoke. High centre of gravity in most engines.
The plan of constructing boilers having fire-box shells and smoke-
buxes level with the barrel of the boiler, thereby giving greater
strength as also economy of production. The almost universal
application of GifFaiii's patent water-injector for feeding boilers.
1^ apylipatioo of Alleu's straight link motiua, a Mk, ■s*\i!iiu'i&

I

152 ENGITTEEltlNG FACTS. rCrv, HL' '

iloiibt, giving tlie very beat reaillts either in full gnar or expnn-
sinn. Oiir experiejice of thia link, aa also that of the Scottish:
Central and North British Bailwajs, is, that it is ic
chI in repairs and first cost than any other, wliile it gives t
actitirate results in the distribution of steum in the cylinder, thei
" lead " being nearly constant for all degrees of expansion, whila
the ease with whicli the link is reversed, owing to its being " aetfr
balanced," ia a great advantage. The material from which e
uf the working parts of locomotives are made, promised in futnn
til be chiefly steel, produced principally from cast-iron, it bavin;
began to find its way into practice with the best results. Mat)}
difficulties will, however, yet have to he overcome in the working
pf such steel, such as hardening large pieces without the cracking
and twisting so often accompanying such operations.

The tendency in locomotives is — owing to increased apeei
and consequent boiler power — an increase of weight, but i
seems rather anomalous that enormous dead weights, such as 3(
and 50 tons, should be propelled over our lines fur the pnrpoai
of gaining sufficient tractive force to draw a few carriage* of j
liiipB only 50 or 100 tons more. Yet sucli is the cose, and thi
experience of our railways of late has been, that powi
cannot be attained without consequent weight in the locomotive
What the introduction of steel as a material for the diSerent p
of a locomotive (boiler included) may do to reduce this remains U
be seen. Certainly such enormous weights are not al}aolut«ly n»
cesaary to the power and speed of the locomotive beyond theii
being inseparably cuoneeted with the present known material
from which we fashion the parts requisite to obtain such pOWOB
The Engineer on this subject says, — "Every part of a locoroo
tive engine must inevitably have weight, and a certain amonni
of weight is, per m, desirable, in order to give adhesion to tht
driving wheels. For the latter pnrpose, however, every exprei
etigirie is from two to three times too heavy, even witbout it
tunder, while of the 50 tons of a first-class engine and tender, tbi
adhesion of 10, or at most 13, tons would geuerally suf&oe fi
I the heaviest express traffic. There is, therefore, a very wjdj
kjiiftrgin for the reduction of weight in locomotives, provided Oidj
streiigtli can be retained. We may remember, is
•, that the very weight of the locomotive and tfiodfl

Loco. EscJ WEIGHT AND SPEED OF LOCOMOTIVES, lal

often amounts, in the cnse of exprwB trains, to one half, or mora
thau one half of the total weight moved. 1^8 problem, therefoie,
is Bomi-'what simpler than that of the reilitctiou of the weight
fur a given power by aay one ha!f^ for, in proportion to the re-
iluctiou of weight, leaa power is actually requited. To move an
engine, tender, and a train of 50 tons, or say 100 tons in aJl, at
the rate of 50 miles an hoTir over an ordinary good and nearly
level railway, at least 400 indicated horse-power are required,
and with very moderate gradienta from 600 to 600 horse-power
would be necessary. But if the carriages could he drawn at the
full speed with an engine and tender of but 30 tons, not mora
than 300 horse-power would be required on the level, and in the
same proportion less than the 500 or 600 horse-power neceasary
on gradients with the heavier engine. If, ujwn any given Bystem
of cunstruction and general Rcale of proportions, 400 indicated
horse-power be obtained from an engine which, with its tender,
weighs 50 tons, only 37^ tons total weight should be required
for 300 horse-power. But if we assume that the resistance, equi-
valent to 300 horse-power, will, with a train of 50 tons, admit of
an engine and tender of but 30 tons, let us inquire whether it be
not really practicable to bring down the weight of our present
heavy express engines, including tender, to about that standard.
In other words, cannot the weight of locomotive engines be di-
minished, through improved construction, to the extent of one-
fiilh of their present weight, a fixed total amount of weight being
in any cose reserved for the driving wheels, to insure their adhe-
sion to the rails?

" Let U8 first refer to the general proportions of the engine,
apart from the dimensions of the boiler. One way of accumu-
lating weight in locomotive engines is by oilopting driving wheels
of groat size. Ifow it would appear almost uimscessary to ob-
serve that only an increase in the evaporating power of the boiler
Ciin really increase the power of a locomotive engine. "With a
given boiler, a Inrga wheel and large cylimiers cause a positive
l.iss of power by entailing increased weight, the resistance of
which can only be overcoino at the saciifice of tractive power,
otherwise commercially and mechanically applicable to the niove-
iiieiil of useful load. Thus, with a given size of boiler, and a
l^ivuQ pressure of stetm, a 15-in. cylinder, 20-in. stroke, and 5-ft,

r

124 ENGINEERING FACTS. [Urv. rll.

'wliw Is, have precisely the same tractiTe jwwer, and can draw the
n&aia train at the same speed, aa an I8-in. cylinder, 24-in. stroke,
and 8ft. Sin. 'rfheeL Exactly the same steam, would be used in
each case, hnt the pistons of the smaller engines would, at lifty
miles ail hour, move at the rate of 933 ft. per minute, whito
those of the larger engine would run off but about 650 ft.
high speed of piston presents no disadvantages whatever if ampli
wearing surfaces are provided, it heing only necessary to hav<
larger steam and eshau.it ports for a given diameter of cylindeij
in order to admit a correspondingly greater volume of steam in i
given time. We may he excused for mentioning that thf
Americans work small-wheeled engines at a good rate of speed
say 40 miles an hour, and that fur a 16-in, cyhnder, steam port
liin. long by l^in. are about the smallest employed, while lor 16in
cylinders there are instances of ports 17in, to ISin. long by lin
or l^in. wide. The valves have a maximum movement of froo
4^in. to 5in., at wliich steam is admitted for upwards of 90 pi
cent, of the stroke, the movement of the valve, when cutting o
at three-eighths stroke, being 2^in., which with a lap of Jin. at eao
end of the valve, gives an opening of the steam port of Jin. — Jii
of which, when running nearly in mid gear, is lead. TIi
American engines have cross-head bearings of great size, a »
of four guide bars, two above and two below the piston rod, bein[
provided to each cross-head. The guide bars are, each, &om 3 Jim
to i^ia. wide, giving from Tin. to 9in. of total width, while till
hearing of the cross-head is from 14in, to 16iu. long. Many
16-in. cylinder engines made in Amerira have one square foot of
hearing surface on each face of each cross-head — one square foot
of hearing against the uuder side of the upper bars in running
fiirward, and the same extent of surface on the upper side of the
liiwerhara in running backward. With such proportio
connecting rods of from 3 to .SJ times the length of the stroke,
almost any speed of piston is practicahle, the higher Che speed,
of uourse, the lighter being the parts required to develope a given
amount of power.

Ig^How, comparing an engine with 15 in. cylinders, 20-ui.
fB^Usnd fi-ft. wheels, with another having I8-in. cyUnder^
^^^^hfte, and 8ft. 8itL wheels, it is evident that, even with ■
^^^^K|gsUf the same sine in each, the former would weigh

I. Eire.] SMALL AND LABGE-WHEELZD LOCOMOTITXS. IS

I tons 1b63 Uian the Utter, probaUj ax tcnss les, AimI*
Kthe two engine^ proTiding only that a given fixed weighs
I twelve tons, was retained upon tbe driving wheels of each,
pld not only have the same ab«)lute power, bat the ligfat«r
>, with equal power, wonld draw a load aboat eight Ions
irier than that of which it^ rival woald be capable. Practi-
f, therefore, the smaller engine, having six tons less weight,
' 1 be the more powerfal of the twa But, leaving out of
ration for a moment the opportunity for drawing a heavier
t, the boiler of the small engine might be fiomewhat dimin-
* 'a aixe, and still be capable of supplying steam for drawing
d equal to that taken by the larger engine. If we make the
npariaoa between 17-in. cylindets, 24-in. stroke, an<l 7fl. 6in.
'9, and 15-in. eylimleta, 2i-'in. stroke, and 6-ft. wheels, we
J, with & given steam pressure, the same tractive power in
^, and with an increase of piston speed one-fourth greater with
e fi-it. than with the 7^-ft. wheel, we shall consume an equal
poant of steam in a given time, and take trains of equal weight
Yet the IS-in. cylinder engine, even with a
[ler of the same size as that of its rival, would weigh probably
e tons less.

•"Experienced locomotive engineers are aware that the quick
piprocations and more frequent blast of a small- wheeled engine,
a speed, are attended with a lessened consump-
t of fuel This fact was particularly illustrated a few years
I, in- working two classes of engines, the one with large and
r with small wheels, on the old Oxford, Worcester, and
BToIvethaiupton Eailway. It was found that, in every respect,
e best results were ohMned with tbe smaller wheels.
"If to the opportunities for diminishing the weight of a loo-
motive by adopting smaUer wheels, and correspondingly smaller
cylinders and a higher speed of piston, we add those which still
exist for the diminution of weight or increase of pressure in the
toiler and other parts, and the saving which the adaption of tank
engines will allow, it is almost difficult to say to what an extent
reduction of weight may nnt be carried. In the boiler, for ex-
mple, it is believed to he entirely practicable to employ welded
a, thus dispensing with riveting, with its great loss of strengtli,
c^tjte tendencj which appears to be often induced, m ^U% CbM

r
I

]2B ENGIKEERISG FACTS. [Div. lit

of riveted seams, to longituiliual ' furrowing,' already tlie c
nf several fatal locomotive boiler exploaioos. It is found, also^
on many lines, that the dome may be dispensed with with entire
siiecase, and, clearly, with a considerable saving of weight,
saving by the use o£ steel axles and tyres is already considerabk)
driving ajiles with journals only 5^in, in diameter being hot
employed in express engines with 16-in. cylinders and "JS
wheels. Even the Injector peniiits of a saving in weight,

" An opportunity for a very great saving in weight is aSemi
in the arrangement of the tank engine. The only object in carry-,
ing a large supply of fuel and water is, of course, to enable loD^
distances to be run without stops. Yet 1^ tons of coal will
carry the heaviest express from London through to Rugby, e
although nearly 9 tons of water are req^iiired, it has already beea
found practicable to 'pick' this up when the train is under way,'
1000 gallons of water, weighing 4j tons, wonld, one would a
pose, be the most which an express engine need ever carry, and
thus, if the sujiply of fuel and water be carried upon the engine,.
a weight of 6 tons at most should suffice for every really necessary
purpose of the tender now carried, the weight of which a
ally exceeds 21 ton a."

A correspondent writes to the same pax»er {Ifie Engineer), oa
tile subject of Light Licoinotives, as follows: —

" It appears anomalous to use a machine weighing from one--
tliird to one-half the load it is required to draw, to convey the
Paid load to its destination, yet we are doing this every day erf
our lives. We use engines weighing from 30 to 40 tons to
ctmvey trains whose weight averages from 40 to 60 tons only,
unless in exceptional cases. It mut^t be allowed that we cannot
move a. poaiid one inch without the expenditure of a certain
amount of power, which power represents money. With r
to a locomotive, increase of weight also entails another sou
pxpense, viz., the wear and tear of permanent way, and this last
item is rendered a very serious one from this cause alone, with-
out considering any other. It must needs be a strong and well-
laid roil that has to bear the cruHhing load nf a 40 ton engine^
crashing over it at lifty miles an hour. No wonder if engineera
find their rood anything but a permanent way under Buch
tnaiment

Loea Bwo.] LIGHT WEIGHT LOCOMOTIVES, IJ"

" This, however, ia not what I would seek to draw attenlicui
t'> go much as to the ejcpense of the engine iUel£ liailway sta-
::~tics show the coi^t of each, ton carried over each mile of grouiut,
• 1 that, in other words, every ton nf doaJ weight moved over
'..'ly space, however small, represents a certain amount of monej
i.vkaa out of the dividends. It is true that we cannot obtain
' .il.y miles an hour from a light engine— but why J for the
-imple reason that the term 'light' is mrrcly a relative one, and
uitmna that the engine is small, aud therefore light; or in other
words, the teim ' light ' 13 sometimes irapmperly used for the
mure correct one ' smalL' We cannot then get a high speed
iruni a small engine. The only influence that weight could exert
would be to retard instead of increasing speed. An engine that
lias to convey large trains at a high speed must liave large heat-
ing-surface and boiler room; to carry this large boiler we require
a strong and heavy framing, and irom this increase of weight we
are compelled to go a step further, and pn>vide wlieels and springa
(if suitable strength to bear the load with safety, which entails
another increase of weight, so that increase No. I brings us to
increase Ho. 2, and both these bring ua to a third increase: and
so. like a boy's snowball, it goes on accnmulating till it assumes
a formidable magnitude. Eveu bpre, however, we are not con-
tented, but actually increase tliis weight wantonly, by the addi-
tion of heavy iron foot-plates, which is considered requisite to
give the ' driving wheels sufficient bite ' to enable them to draw
their loads. Now, tliis last item might surely be done away
with by proper distribution of the weight, and hanging the
engine so as to get most of the weight on the driving wheels.
That this is already done to some extent I am aware, but still
so long as we are (or think we are) obliged to increase the weight
for the sole purpose of gaining adhesiou, I do say the principle
is imperfectly carried out. We have ample, indeed I say too
much, weight already at our disposal for this purpose, if brought
to bear to its utmfist extent, so that the want of ' bite ' should
not justify the use of unnecessary weiglit

" To make our locomotives lighter without diminishing their
power, I woidd suggest the following methods : — The use of
steel for the boiler and all other places where it could be intro-
dmwd. That we should try Jjow far the p

ENGINEERING FACTS. fDlv. JIl

of rivetiug could be adopted in making the boiler, as it promisaa
I greater sti«ngtb than rivets, and by this means we might havi
a strong a boOer with ^ inch plates as we now have with donbh
I that thickness. The slides should be fitted with a good balane
1 ing apparatus, so as to reduce their fiiction to a minimum, whidl
. woald enable us to use a lighter 'motion.' I would make tb<

)n rods hollow, and the connecting rods shouM be made—

' flat, of a I Bection ; or, if round, hollow ; the motion-rods bei

aile in the same way. I wonld abolish the tender altogetii^

and make the engine on the tank principle, thereby gaining a

the weight for adhesion ; and, to increase this latter, I wool

couple two pairs of wheels. I do not see why even express en

} gines should not have ' coupled ' wheels, wliich, with the use o

equalising bars, would secure all the weight almost for the diiv

ing wheels. The 'steam dome' I would also dispense with, a

it costs more and causes more trouble than it can conipenstit

for, and weakens the boiler materially, which weakening conld

not be afforded with ^ inch plates.

" I would use a comparatively snuill tank, only large onongli
fact to contain water for a nui of ten or fifteen miteft
To supply the engine with water for a long continuous ruiii'
I would introduce a far more extended use of the trough
between the rails, having one at every station fur each line of^
rails. Tlie water coidd be easily kept from freezing by not
letting it into the trough till a short time before the train i
),' and at any important station the M'ater would have
time to freeze. Where the stations were too far apart, I would
have tanks and troughs placed under the management of th«.
ailesman who had charge of that portion of the line, or some'
ither suitable person, so that there would be always an ample
supply of water. The cost of laying down and keeping those
tnragha in repair would be little compared to the saving by
having hght engines, and getting rid of those cumbersome
tenders. I would likewise allow very limited room for canying i
oal, only sufficient to bring the engine from one stopping place 1
to tlie next, with sufficient margin, of course, for contingencies. '
There would be little expense in maintaining a supply of coal '
at each station for the use of that portion of the line. Coal
' trains in most cases passing eo frequenUy would form a ready .

M

Id ]
nl ]

i. Eko-J smoke OONSPMPTION IN LOCOMOTIVES. 129

mpply, RU<1 in exceptional cases a truck load could fas
bit fa; ftoj nf the munerous goods tr^iu. It is tidieulous, the
ition of sending coala to a great depot — perhaps forty or fifty
"" i§ distant— to be carried hack again by the various engines
I which it may have been served out — a conEiderable portion
Rt thus going over the tine twice. Were it possible to fancy
3 of turnpikes established on a line of railway, and that
|) locomotive engineer had to pay so niu<;h a ton fiir his en-
B passing through, I feel certain we would sec a vast dindna-
■ in. their weight in a very short epajie of time. But it id
li isilwaya now as it was with steamships some years ago —
) in the Mler were not amalgamated The sliipbuilder
i notliing about adapting hia hull to the engines, and vies
So it is with the locomotive engineer and the civil one
', the former does very little for the road, and the latter as
I for the engine; but i^ as already said, the latter eoidd
a tannage for the use of his road, and the Ibrmer for any
'ment ' that would occur, we should see considerable im-
ivement, both in the safety of tlie public and in the amount
I the dividends. Practicaliy, this is impossible; but if we
I reason to think thiit under stimulants we could attain
^rorement, we ought to try to get it without such adventi-
£ aids."

■ Upon the subject of smoke conaumptioa, and tbe application

BGiSard's injector, tbe " Mechanics' Magazine " makes the fol-

ing remarks : —

" The introduction of good coal as a substitute for coke has

become almost universal on all tbe raih^ads in Great Britain,

the saving effeeted being very considerable, amounting to many

HkniBands per annum on such lines as the fi^orth -Western. All

^Hpigs considered, the production of smoke ^m coal-burning

^Bjpnes is not very great, and with a little more care might poa-

^BiJy be reduced to half what it is at present. Even now, how-

^Ber, it c9n scarcely be consideied a nuisance, except hy tbe fae-

^^uioue. With a roomy fire-box, and a free admission of air

^■ipre the fire, almost any coal can be burned without smoka

^H ia not easy to secure these conditions, however, in tlie loco-

^■ptive. The furnace doors are fiii too small to supply all the

^Btje^aiied if perforated ever so closely on W36 "WiVUaW ■^m-

ENGIKEEEINO FACTS.

^r 130

^^ ciple; and their fire-boxea are too eonfinfid to permit flame t-o
^m exist iu them aa freely as it ought Tlieoreticallj the g
^H oliooltl remain ia the hox till ooRsumed, a condition impossible
^H to secure completely. The seoop deftector has been liiljuduce«£
^H M a snbstitute for the perforated fire-door, and the brick fire-
^B bridge to detain the gases and aid their combustion. Thesi^
^B combined with a long gnite and a deep fire-bos, give better pia6-
^r ti<^l results than can be derived from tlie use of the combustioa
chamber, which ia rapidly going out of favour. The employ-
ment of this expedient— to designate it by its proper name — en-
taila a shortening of the tubes, which is fatal to economy, and

> materially hastens the destruction of the smoke-box and stack.
An increase in their number, and reduction in their size, as prae-
tised at one time on the East Lancashire line, where 437 kibes
of 1 J in. diameter were crowded into a shell of but 3 ft. 8J- ii
outside diameter, has given anything but good results, either ia
the economy of fnel or the durability of the boiler. Mr. Wil-
liams and luany others have endeavoured, ore now, to prove that
length of tube was superfluous, inasmuch es experimenta showed,
that evaporation was almost wholly confined to that portion of
the tube surface nest to the fire-box. Most of these experi-
ments were made with model boilere, employing gas jets to pro-
idiice the necessary heat Tlie results obtained were fallacious.
"We have every reasim to believe that a loeomotive boiler with 2
in. tubes evaporates a very considerable quantity of water close
to the Bmoke-box when travelling at a high speed. It ia taken
for granted tliat flame will not enter a 2 in. flue for any consider-
Able distance; this is perfectly true with a moderate draught.
When the lice is urged, however, by the powerful action of the
blast-pipe at high speed, such flues become filled with flame
from one end to the other if not more tlian 8 or 9 feet long.
Any engineer can determine the fact for himself by drilling a

»fuw sight holes in the smoke-box door. It ia well known thiit
by exposing a Davy lamp to a strong current of airj'ftamo will
be forced tlirough the wiie gattze, and accidents have ensued e
now from this cause. Fkme will not enter small tubes from
precisely the same reason that it will not pass the gauze meshes
of the lamp; but the opposing force can bo overcome without
JMcaltf, and notliing ia cnsii.'! than to compel flame to entw

L Em.] smoke consumption IN LOCOMOTIVES. isi

traveiae a tube of moderate diameter. Huw niacb smoke
bu consumed (to popularize the action whicb takes ptac«)
■3 of a locomotive boiler, is a subject well worthy
cssreful inquiry. Largt; and long flues may, after all, be quit)?
petent, when aided by a roomy iire-bex, to supply all the
necessary for tolerably perfect combustion, without entail-
any of the diflicultied which beset the combustion chamber,
dB experience proves, without any risk of wasting fuel ; for
heat ie lost in permitting the escape of uuconsumed gases
lugh small fiues, than can poBsibly follow frum the use of
flues, wliicli, altlwugh tliey offer less heating enrface, yet
iuder that surface more valuable by pennitting the existence of
9aiue within them.

" Though locomotives consume the produtta of combustion
m<)derately well, we have do reason tu conclude that their eih-
ciency, or the economy of fuel burned, is as yet anything like
wliat it should be. The average evaporative duty of the loco-
motive boiler doea not much exceed 8 lb. of water converted into
Et«an), for each pound of coal put into the £re-box. Lord Dun-
douald succeeded, years ago, in evaporating nearly 13 lb. of
water, for each pound of coat consumed, in a marine boiler not
of the best type — a result generally attributed to slow combus-
" Esperimenta conducted in France, however, fail to confirm

a conclusion, as the employment of a forced draught, with
combustion, was proved beyond dispute to add equally to
efficiency and eoimomy of a boiler properly constructed,
though cot specially intended for the employment of the prin-
ciple. The straight sides of the locomotive fire-box — or, worse
atill, those which are wider at the top than at the grate — are ex-
~ imely unsuitable for communicating heat to the water auiround-
them. A vertical surface is certainly not more tlian half fus
steeply inclined over the fire, a film of steam re-
ining continuously in contact with the plate, and preventing
it absolute contact of the wnter with it which is es^eiitiiil ti>
rapid production of steam. Mr. Sinclair, of Glasgow, con-
ited the fire-boxes of some of his small locomotives with in-
aidca with the greatest advantage, and the princijile dn-
general adoption. It reduces the size of the tube-platf,
;r, so much, that in order to carry it out na \\. sivQuli Vni,

of tht

132 ENGISEERING FACTS. [Dii. HI

grates must Lii iiifiile mueii wider tLuii tliey now are — a difficult
job on the nan^w gauge, froiii tlie position of the trailing and.
driving wheels. Anthracitu coaL-hnrning engines have been a
oessfully constructed in America with grates 7 ft. wide aer<.«a
the tract, and as much as 6 ft. long. Were auch enormous
grates adopted here, it might be fnuud advaatageoua to cover
them round the sides with fire-bricks, wliieh would protect th»-
phttes and conduce materially to the regular production i
steam. A thinner fire, too, might be maintained on tbe grate
with, manifest advantage, aa far as tlie prevention of smoke li
ooncerned.

" The feed-pump is rapidly being displaced by the injeotor..
On the North-'TCestern it is only retained on a few old-fashioned
engines, as much, perhaps, fur the purpose of comparison as from
any other reason. A feed-pump, filled with air-vessels and all
the requirements necessary to hydraulic machinery, driven at a
high speed, ie really rather a complicated piece of machinery,
easily put out of order, and exposed to risk from frost, &c.
understand that on the Eastern. Counties line, where the appli-
cation of the injector is all hut universal, a very conaiderablB ■
saving is effected in the item of feed-pipes alone. Sat om
ever burst when the injector is employed, while with feed-piimpa ■
of the best construction they were continually being raptured,
either by the irregular action of the pump or by frost. The
engines, too, are found to keep their steam belter when running
if the boiler is fed by the injector than when supphed by a pmnp.
There is httle doubt that the expenditure of steam is far greater
with the former for equal quantities of water fed in than with
the latter ; but this really is a matter of very little conaaqoenoe
when we conaidei- the advantages held out by the injector. The
atmphcity of its aiTangementa, the ease with which it con ba
fitted, and, we may add, the certainty of its action under all the i
varying circumstances to which a locomotive ie exposed, render
its application one of the most important improvements the loco-
motive has received of late years."

. On the subject of some of the internal disturbing forces of
locomotive engmes, a paper was read by A. W. Makinaon,
H. Inst C, E., before that society. The following is a reoapitu-
\tioa of such: —

Loco. Esc] ISTERSAL DISTtmBING F0BCE3. 188

" The author stated that, allhongh the pcnuaiii'iit way of rail-
ways had been much improved of late years, it was etill a quuH-
tion fur inquiry, which waa proposed to be undertakeu in tlie
present paper, whether, having regard to the aafe tranGit of pasa-
engera at the high speeds now demanded on trunk hnes, tlje
locomotive engines were as free as possihle from auch internal
disturbing forces aa had a, tendency to cause them tu leave the
rails.

'' In elucidation of the subject, the indicator diagrams taken
from the cylinder of the ' Great Britain ' locomotive on the Great
Western Kailway, in 1847-49-50 {ttide Clark's 'Eailway Ma-
chinery'), at the velocities of 26, 35, and 52 miles per hour
respectively, were selected for examination ; and from these a
svnea of diagrams was constructed, which exhibited graphically
the different forces acting in b, locomotive when in motion,
numerical values being assigned to each of those forces. *

" The disturbing forces were divided into two classes — first,
those which were generated by the revolving parts of the engine,
113 the crank, ci'ank-pin, and half the weigl)t of the connecting-
rod J and secondly, those which were generated by the recipro-
cating masses, as the piston, pistoE-tod, erosa-head, and half the
weight of the connecting-rod, &c. As it was understood thai,
iTi the practice of the first locomotive engine makers, the proper
counterbalance for the revolving appendages waa now always ap-
pliod, tliat class was not considered.

"The nature and origin of the sewjnd class of forces were then
L x^imined in detail It was ohserved that, if the circular path
. if the crsnk-pin around the axle was divided vertically by a
• iiaight line through its" centre, then the crank arm would ap-
i'riximately coincide vrith this line, when in its positions both ul'
_;roatest and of least velocity; and while the crank-pin moved
Hicough 180° from its position of the greatest to that of the leoHt
\f-locity, the reciprocating appendages developed preBBares in
fiivoui' of the motion of the train, but 'w lwftAjWPwAtfr om the
position of the least to that of iha gS^BK^BKtmj^V-
l.'undages offered resistances to tbe jiai^^^^^^^^^^^^B ^
ii was shown that, in general term*
'-urea generated hj the i-in insrtiu c'

ETTGINEEKINO FACTS.

[Div.

^^M to llie mid-stroke; tlie pressure during the eecimd ]ialf uf tlie
^^B forward Rtroke and the firat half of the back stroke asskting thu I
^^Bmotinn of the train, and during the second half of the bock stTokij 1
^^Band the first half of the forward stroke opposing the motion of I
^^Kthu train.

^^H " It was only by adding the pressure thus developed by m't I

^^Btner/ia to the simultaneous eteani pressure, that the total efficient I

^^Ktroctive power generated at any moment iii either cylinder conldJ

^^Hbe arrived at. The variation in amount of the tractive powerl

^^Kthroughout one stroke of the piston wtis thus seen to be niueliB

^^f greater than when the steam pressures alone were considered. T

I By adding together the amounts cf tractive power simultaneouslj'a

developed in the two cylinders of the ordinary engines, wil'

cranka at right angles tf> each other, the total tractive force'*

the train at any point in one revolution of the driving wheell

was arrived at; and the diagrams exhibited showed the j^

irregularity in amount of the total tractive force, operating t

produce fore and aft motion in the engine and train. By c

pftring mth each other the aujoanta of tractive force develojM

simoltaneously in the two cylinders, the tendency to siciK

motion in the two-cylinder engine was shown, and t ' ~ ''

graphically in one of the diagrams.

" In conclusion, the author submitted that s
engine would be free from all sinuous motion : that a
an hour it would have about the same, and at hight
leas, fore and aft motion, than the ordinary two-
that by supplying the driver with the iinaiir: l
as mucli power us was expended in putting th
a single-cylinder engine would have oqu.il l-i;:
, with the two-cylinder engine; and that Lln' use
I engines for passenger traffic would, by rt'iiii'ii'
r the carriages, render railway travelling Ics.-; uii
the cost of locomotive power, arid the es|if ii
I way; whilst the dead weight of the p!i;;'ji
[ tear of the several parts, would bo dimim.slu
' "The appendix contained matheniMtJial
formulfe showing; 1, the relation betwcin
I piston as observed by the indicator, and tin'
t the cmnk-piu ; 2, the disturbing furiic ge

ENGISEERING FACTS. [Dtv

^^P to the mid- stroke ; tlio preaaure during the second half of tlie
^^M forwai'd strolce and the first }ialf of the back stroke assisting tin
^^B motina of the train, and during the second half of the hack stroki
^^M Biid the first half of the forward stroke opposing the motion of
^^M the train.

^^M " It was only by adding the pressure tbus developed by eu

^^P inertia to the simultaneous steam pi^ssure, that the total efficient

^^ tractive power generated at any moment in either cyhnder could

be arrived at. The variation ia amount of the tractive power

throughout one stroke of the piston, was thus seen to be much

J gi'eater than when the ateam pressures alone were considered.

^^f By adding together the amounts cf tractive power simultaneously
^^M developed in the two cylinders of the ordinary engine^ witli
^^B cmnks at right angles to each other, the total tractive forco'coi
1^" the train at any point in one revolution of the driving wheel
was arrived at; and the diagrams exliihited showed the great
irregularity in amount of the total tractive force, operating to
I produce fore and aft motion in the engine and train. By com-

^B paring with each othGi the ainoaiits of tractive force developed
^^m simultaneously in the two cylinders^ the tendency to sinuous
^^M motion in the two-cylinder engine was shown, and exhibited
^^B graphically in one of the diagimns.

^^m " In conclusion, the author submitted that a single-cylinder
^^M engine would he free from aU sinuous motion; that at 26 miles
^^1 an hour it would have about the same, and at higher speeds far
^^M less, fore and aft motion, than the ordinary two-cylinder engines :
^^1 that hy supplying the driver with the means of applying about
^^K as much power as was expended in putting the breaks on hard,
^^B a single-cylinder engine would have equal certainty of starting
^^M with the two-cylinder engine : and that the use of single-cyliuder
^^B engines for passenger traffic would, by reducing the oscillation of
^^K the carriages, render railway travelling Ipss unpleasant, and reduce
^^H the coat of locomotive power, and the expense of maintenance of
^^M way ; whilst the dead weight of the engine, and the wear and
^^H tear of the seveml parts, would be diminished.
^^H " The appendix contained mathematical investigations and
^^m formula showing: I, the relation between the pressure on the
^^^jmton as observed by the indicator, and the equivalent pressure
^Hk £&« crank-pia; 2, the ' "^ iatva geiafink«L ^^ Uua uu^

]

1,0-x). eno.] equalization of motion in locomotives, is*

luluHc«d revolring raaasee; and 3, tlie preMiires, referreii to tlie
i;riink-pin, generated by the vU iiierfia and varying velocity of
Itie reciprocating parts of a loi»motive in motion."

In the discussion which took place at an ensuing meeting " It
was argued that the lateral motion of railway traias was not
Attributable so much to imperfections in the locomotive engine as
tu defects in the permanent way, which it was di£Eicult to keep
in perfect order, from the variations in the temperature, the
tianges iu the weather, and other causes. The tendency of the
: I'^iprocating moseed to produce oscillatory motion must be rela'
'ively less thou formerly, owing to the greater we^ht of the pre-
sent engines. It was doubted whether the re-introduction of the
single-cylinder engine would result in any advantage, as the diffi-
culty of starting a train with such an engine would, under certain
circumstances, be insurmountable ; and the ell'ect of having only
a single central cylinder would be to raise the centre of gravity
of the engine, thus creating a serious objection. Tlie late Mr.
Geoi^ Stephenson had endeavoured to equalize the motion, by
the adoption of a three -cylinder engine which had been in use
for many years on the North-Eastern Eailway. In that ease
there was a large cylinder in the centre, and two smaller ones at
the sides j but the cost and the complication of the parts of tliat
engine prevented its general adoption. It waa, moreover, doubt-
ful whether, even at the highest velocities, there was any apparent
differance in the steadiness of that engine, as compared with
others in which the revolving and the reciprocating masses were
well balanced. However perfectly an engine might be balanced
when it left the manufactory, after it hod been running for aonie
time, from numerous causes the springs lequired re-adjuatment.

" As regarded the disturbing forces which were said to arise
from the pressure of the steam in the engine, it was contended
that the unbalanced pressure upon a beating at any time was only
that dne to the force driving the engine by that particular bear-
ing. If it were possible to suppose a ease of a locomotive with
only one wheel, Kuch an arrangement would no doubt tend to
produce sinnoua motion, with a force proportioned to the di-jtance
of that wheel from the centre of gravity of the engine. But
with two wheels keyed fast upon the same shaft, uf sucli strength
as not to yield appivciahlj under torsion, tUere oouVi \« lua iiSjo-

I ISB

ENGINEERING FACTS.

[Div. m.

e of preasnre {of tliia Idud) between tlie two sides of the

Igine; and that was ttiie whoUy irrespective of tlie namber of

■ cylinders, or of the places whore they were put. An engine

J capable of produciiig 1 tun of tractire force must distribute it

r the two hearing, and there would, therefore, be ^ a ton on

I each bearing. Even if the engine were driven by one cyKnderj

B tnanifeat it could not put a pressure upon one side of that

I engine which was not equalled hy that on the other side at tha'

e moment ; and that there conid not possibly arise any ainuOttS

motion from the driving pressures. Beferring to the disturbancea

eansed by tlie momentum of the parts, it was observed that,

thoQgh the force of the parts in motion increased as the speed

became higher, the times through which they acted decreased;

for it could be shown, that the distance, through which these

fbro«8 were capable of moriug an engine, must be the earn

all velocities.

" As to the distance which the forces spoken of ought to i

an engine, it was demonstrated tliat, with a locomotive the crank

shaft of which was making three hundred revolutions a minute,

with a length of crank pin of 1 foot, producing a velocity of 63

miles an honr, and the moving parts belonging to each cylinder

of which engine weighed 500 lb., the total weight of the machine

being from 27 to 28 tons, there would be an amount of motion

equal to only I4-100ths of an inch. Audit must be remembered,

that while this would he the extent of each motion, the number

if such motions, as they occurred at each revolution of the crank

I shaft, could not increase for a given distance travelled

("although from the greater number of revolutions per minute

iTiigh velocity over a low velocity, there would be a greater i

I ber of revolutions in a given time.

" Supposing, however, that the disturbances were as great oa
I had been represented, then a better remedy than the siugle-cylindi
I engine would be, either the plan introduced by Mr. Bodmer i
I 1834, and modiiied by him in 1841, of having two pistons i

e cylinder, both the piston-rods issuing at the same end, ouo

I being made hollow to adroit of the passage of the other; or the

J duplex, engine brought forward at the late International Exhf

I'bition by Mr, Hoswell, the Engineer for the Austrian States

~'ailteay Company, who proposed to employ four cylinders — tWQ

x Kjio.] unbalanced pakts of locomotives, ist

If giving a forwan!, anil the olljers oil aft motion. It wae »tat«<il
' "q the year 1836, the late Mr. W. Weallens bad designed
ib engine with fotir cf linders, siiuilai in every respect to that last
■■ Ito.

invested, that the Paper would have been more com-
1, i^ as well as pointing ont the forces tending to produce
1 motion, or oscillation, the nieaaure of the effects of those
jaciea had been calculated. Taking the forces exactly as
1 by the author, it was remarked that the total lateral trans-
[on, to the right or to the left, ia the mass of an engine by
e forces, would be in one case l-6th of an inch, and in anotlier
pOth of an inch ; and at the velocity of 35 miles an hour, each
ces would act during abont ^th of a revolution; and
t aa there were two revulutions in one second, the diagrams
mted forces acting during the ^th part of a second- The
nit of this theoretical investigation had been to show, in a
ible form, a series of tendencies vhich certainly existed, and
^wing where they existed, however slight, precautions could
e taken to diminish their effect. It was evidently most impor-
tant to allow sufficient play between the flanges of the engine
and the rails, — that they should not fit too closi-ly, It was oon-
eid^red that the estimated amount of the o»;illatii>u was so slight,
that any great deviation from the established form of engine
could not be recommended r certainly not the substitution of a
single- cylinder engine, with all its mechanical inconveniences, for
the present double-cylinder locomotive.

"With regard to the effect produced by the anbaliinced reei-
prDcating parts of an engine, it was thought that the l-5th of an
inch could not be acctipted as the real ineasiu-e of the sinuous
motion of most engines. In practice it hod been noticed that,
even with a good road, the lateml oscillation amounted to 2
inches, and if the road was in bad order, then it would be much
more. But this did not express the evii in its true form ; as it
was (or might be, at any instant that the flange was in contact with
the rail) a qaestion of the amount of force exerted against the
rail, tending to bend the rail, or to break the chair. As to the
incing of the I'eciprocating mosaea, direct trials were reqiured
■■ show the alterations necessary to he miide in the positions
Ln&s^te of the jmrt^ bai'om tlie ljuat> lUiiult. au\M W m\.\«i\, ,

ISS ZNGIKEERING FACTS. [Dit. HI

There were many oLjectiona tu a single ojiiuder etigino„
besiJea the difficulty of atartiiig the train. Among these, the
irregularity iu the tractive power, in place of a somewhat dui-
tributed foree, was alluded to, aa likely to cause a jolting
action, which might give rise to accidents, Jrom the fracture
of the coupjinga; and it waa shown that, when using full,

im throughout the atrokn, the masimum and minimum rotarji
jiower of the double -cylinder engine varied iu each quarter of a
revolution of the cranks, nearly in the proportion of 1 i to 10,
whilst in the sin)jle-cyliiider engine the variation waa as much a
20 to 0. It was suggested that the moat uniform rotative powef
would be obtiiined by using two cylinders, and cutting o£f th»
eteam a little before and a little after the half stroke. FurtheFi
it would be a great improvement, if locomotive-engine builder^

3ommon with marine engineers, would use steam-jackets, botii
to the cylinders and their covers.

' It WHS bilieved that the disorepaney between the amount of
the lateral motion produced by the disturbing forces as calculated,
ftud as found in practice, arose from the circumstance, that the
theory waa based upon the supposition that the wheels i
without flanges. When the direction of the course of an engine

a high velocity was suddenly altered by any disturbing force,
the undulation of the engine brought the flanges into violeut
contact with the rails, and the elasticity of the rails caused t
engine to rebound, or rather glance ofi^ against the opposito
rails. Wlien the rebound happened to be simultaneous with a
disturbing force acting iu the same direction, the maximum
oscillation was caused; but the rebound was in some degree neu-
tralized, when the disturbing force acted simultaneously in the
opposite direction. Li support of this view it was adduced,
that the oscillations of an engine were not coincident with ita
polsations, as they would be in the theoretical case of an engine
without flangesj but that they wrere very irregular, sometimea
estending over a period of eight or ten pulsations.

" In the deductions as to tho extent to which the oscillatioa
of the engine was occasioned by the varying operations of the
steam iu the cyiinilers, the whole wi^ight of the engine had been
taken into account; whereas, it was contended, that only that
pait of the mass which was upuu the springs ought to be con-

JLono. Esc] OSCILLATING UOVKBlEirTS IN LOCOMOnVES, 13S

Tho motiou coiomuuicated to this jMrtioii of the bulk
iftbe engiae would be in excess of the estiinnted leauite;

D then, the aniouut of oscillation which was known to t-jtist
paid not be arriveil at With a perfect rwid, and an engine
nteljr adjusted, it was not possible to put that engine ex-
' straight upon the rails. Sor could anj slight defects, such
W the wheels being out of truth the ono-huiiilredth purt of un
%ieli, be detected, ^^itht^r were there any means of inrestiiptt-
iii(,' the extent to which these defects prevailed, becauM thef
iiiight be acting either together, or in opposition to each other
mill thus might aid, or retard the oscillatiuu, or tlie tendency ti
letUation, which the backward and foni-ard pressure of the
' Q the cylioders must occasion to the boiler and other parts
Ibnected with it.

■** In reply upon the discussion it was remarkeil, thut if all
"dliition was to be referred to defects in the permiuieut way,
Oi^ht be asked, why travelling on a railway worked on the
biospberic principle was so decidedly superior, in ease aud
~iae8S of raotiou, to travvlling on a line worked by hooam-
tives.. It was believed it had been establislied in the paptr,
that even if the permanent way were malhetaaticolly perfect,
locomotive engines of the ordinary construction would create
lateral and oscillatory movements of a grave character at high
speeds, and results similar to those produced hy numerous small
depressions in the level of the rails. It had been maintained,
that any oscillation in the engine, produced by the internal dis-
tnrbing forces, would be the same at all velocities. Tliis involved
two erroneous assumptions. It hail beifn taken for granted, that
the time allowed for the oscillation varied inversely with the
velocity of the engine, and that the disturbing force varied
directly as the velocity. Now it had been shown, in the dia-
grams, tliat at 26 miles per hour there was a tendency in the
engine to make two oscillations in each revolution of the driving
wheel, whilst at 53 miles an hour there was a tendency to one
uscillation only, in each revolution ; so that the time allowed for
an oscillation was the same, whether the train was moving at 26
111" at 53 miles per hour. The pressures tending to produce
iiscillation were opposed by the friction of the wheel on the rail.
The iliffifTence o£ these two presBuios waa Uie iwvuiv^ iaxxa ^co-

p

no ■ ENGINEERING FACTS. [Dn. Ill,

ducing transverse motion ; and whether this friction was assumeil
to be the one-fourth or only the one-tenth of the insistent load'
on tho wheel, the moving force incrcHscd more rapidly than tha
velocity. Applying the aame dynamical law wliich had beea
employed by several apeaters, for calculating the measure of the
effect of the tendencies to lateral movement of the front end o'
an engine while timning, it was shown that, even so well-pro-
portioned an engine as the ' Great Britain,' at S3 miles per hour,
■with a greasy stale of the rails, would twice in every revolution
of the driving wheel move laterally J of an inch, and ?
Btrike the rail with the wheel flanges. A blow, once origiaated^
between the flange and the rail would, from their elasticity, en-
tail a series of blows at regular intervals of time; and should
any of the series coincide in time aad direction with the con-
stantly recurring impulses to transverse movement originated by
the engine, a heavier blow between the flange and the rail would
follow; and this would be repeated, so that it was coneeivabli^
thatthepressuresshownon the diagrams, occurring simultaneously-
^th the rebound of the wheel from the mil, might ultimatBlf
induce a lateral pressure great enough even to drive the ^nge
of the leading wheel up the rail, and ho to cause tiie engine to
leave the rails,"

A good recapitulation of the past improvements, &c., and oUiec
innovations in the construction of locomotives, appears in tha
following article extracted from the "Mechanics' Magazine;"—

"Notwithstanding the dictum contained in Clark's 'Eailwi
Machinery,' we cannot regard the link motion as otherwise than
imperfect. Its comparative excellence we admit; but with the
growing tendency fur higher pressures and early cut-off, it
fects become day by day more prominent. In order to maint&in
anything like a full pressure on a piston, moving at 800 or 1,000
ft, per minute — a speed fi'cquently reached in express engin
it is essential that all passages leading to the cylinder should not
only be short, direct, and of lai^e area, but that they should ba
Opened and closed with a velocity proportionate to the speoil of-
the piston. Locomotives are seldom worked in the centra!
notches, except when running fiist. The travel of the valve u
tlien shortened, and the ports not only reduced in area, hut opened
aud closed with s tardiness, whicb gcciU^ -nulLta.tes a^iuat tb^

1. Esc] WORKING OF VALVES.

ICO. E:
'autogB to be derived from an early cut-ofl', diagrams 'taken ut
h speed showing a very remarkable loss of pivsaare as the
on pursues its coutse titrough the cylinder. Steam is esti-
ed to flow into a vacuum with a velocity equal to that due to
II ivody of the same density, fidling through a space equal to the
iiiight of a column of eteain of the given pressure. By this
I ;;Il', steam of 1 20 lb. pressure would flow into a vacuum at about
-,U79 Si. per second; but the difference between the velocities of
i;iy two pressures is the velocity with which steam would flow
,:ii.o steam of a lower pressure. At the commencement of a
•'liike, or rather at the moment when the valve first opens, the
iiifssiire within the cylinder is comparatively trifling, st«am then
■ Altera with great velocity; once, however, the difference in the
'i.nsities of the eteam in the boiler and that in cylinders ceases
til be well defined, steam pMses very sluggishly from the former
to the Ifttter, and is little able to overcome the resistance offered
by long curved passages and the contracted areas of the steain
ports. It is very unusual, in consequence, to maintain more than
701b. in the cylinder at high speed, indicator diagrams falling at
once on the commencement of the stroke, long before the steam
is really cut off. The analyzation of such diagrams is not easy,
as it is impossible to tell, without eetting out and measuring the
valve gear, when the valve really closed. Theoretically, the
ports should be extremely short, straight passages, opening di-
rectly from the valve-seat into the cylinder. The groat size of
the valve required to suit such an arrangement has hitherto pre-
cluded its adoption. Mr. Clark gives us good reason to believe
that as much as 25-horsB power ia frequently expended in work-
mg valves as it is — a positive waste of power which it would he
very ijyudicioua to add to. If, however, the valves are properly
balanced, there is notliing to prevent the employment of any size
deemed most desirable; and if we are to adhere to the link and
I'ccentrics, the sooner we have a large valve with a long throw,
and great lap, the better. We illustrate this week a foiro of
li^dance- valve, which, although recently patented here, has been
worked for some time in America with considerable i
I'laimnaison's slide-valves have been adopted fm the Chot
i'cr du Nord since the yeat 1861 with exctillent results both ii
tiie CramptcB ospress said Engerlh goods enguu^. ~^«^^

ENGINEERING FACTSL

I

offi
an-1

cnrapanieB don't like change, however ; and the general introdian
tjim of the balance-valve ia, here at leasts apparently

" Quitting the subject of valves, and resuming the consident-1
tion of the meana bj wliieh they are put in motion, v
iatin^ arrangement lauded for a eimphcity whit^h tliey do :
really possess. The link motion, conaiating as it does of ti
Bccentrics with their rods, atrapB, pins, &c,; a link uften built
of many pieces; and a rucking-shaft with balance weights
eppings; ia really the most complex part of the engine. Ita oxj
is very considerable at first; and from the lapid wear to n
it is exposed, and the nice adjustment which it must prec
ita maintenance forms a large item in the working expensea
the locomotive. We are well aware that this must be a dieti
guishing characteristic of any valve gear whatever ; bnt we helia
that other arrangements not a whit more complicated will g
better results, l^ie mere fact of such a piece of machiner^r, d
cute and finely wrought, answering ita purpose so well, si
rather encourage us in searching for a substitute wliich, not m
simple, perhaps, would regulate the admisaiou of steam to I
ita exit from the cylinders after a &aluon approaching more uea
to theoretical excellence. Coinplesity ia in itself no eviilenee
erroneous design. It only becomes reprehensible when it ia
troduced unnecessarily. In the construction of machineiy, i
ernl ueaally sanctthes the means; and there is no reastm tj
valve gear may not be very excellent, and very complex as
In America, the use of the separate cut-off was long adhen
and is evea atill held in high favour by many huiiders. At
one locomotive in the great Exhibition last year waa ai
and it seems likely enough that its general adoptloi
distant. The variation in the lead, when the rever
in different notches, is not the least ohjectiou to tl
The setting of valves is iu consequence a positive t
one understood, oi at least practised, only recently,
ago it was quite exceptional to meet with a locon*
' beat ' equally. Even yet there
on moat of our great railway lines.

" The question of balance weights, at o
finiticely settled, seema likely to be re-opene*l.

tKM. Eng.]

BALANCE WEIGHTS.

imbtful that it ia good practice to perfectly balance the recipru-
ing parts of a locomotive. One locomotive superintendeDt
removed tbree-eigliths of the accurate coanterpoise from bis
inBS, with manifest advantaga The solntion of the problem
e £11107, ^ ^^^ ^^^^ ^^"■^ '^^ pree^nTO on the piston doc-n
pi accurately represent that on the crank-pin, when the engme
D aoCion, because it is modified more or less by the momentum
Qie piston, rod, and connecting rod — to such an extent^ indeed,
3, that the strain on the crank-pin is much greater
• the tennination of a stroke tlian at its commencement,
fcoogh the steam is early cut off As the equaliiation of the
mpelliug force on the crank-pin is estrcmcly desirable, tending
Bs it does to the stcaiiiness of the entire machine, it is not ini-
phDhable that a heavy cross-head, piston, and piston-rod may he
better for high-speed locomotives cut off very early, than those
of a lighter construction. There can be no doubt, however, that
the wheels must he accurately balanced, and this rule is seldom
or never disputed. In conducting experiments on the subject,
care must be taken to distinguish between the conditions under
which an engine is tried in the shed, and those nnder which it
performs its work on the road,

" There is little tendency I0 alter the praetiee which deems a
single pair of drivers sufficient for express engines. Locomotives
intended for high speeds seldom or never are burdened with
heavy trains, and with rails in good order they manage to pro-
ceed well enough, but, unfortunately, not without doing great
mischief to the pennaueut way, in consei^uence of the excessive
loads placed on the drivers to secure adhesion. Still there seems
to be much weight in the ai^uments which are uiged against
coupling wheels over 7 ft. in diameter, which make 270 revolu-
tions betimes in the minute. The momentum of an S-ft. side-
rod at such a pace would be something tremendous, and its frac-
B would lead to fearftil results. For ordinary passenger trains
is no excuse for limiting the number of drivers to two ;
lupled engines are rapidly getting into favour for this kind
k. For icatbeticat as well as mechanical reasons, the second
F driving-wheels should he placed behind the fire-bos, not
inside eylindera are adopted, the latter position
re iTork oat of the hoiizoutal Uue, s-t^d. ti'[^\;^'^ \&mcj

I

I
I

I

144 EHGINEERIHG FACTS. [Div, III.

difficulties with the smoke-box and framing. A few large en-
gines of this class are doing good service on the North-Waateii^
between Birmingham and Stafford. The driving-wheels are, ^
believe, 6 fL iu diameter, and hence the cylinders do not coma
inconveniently near the ground.

'" Steel tyrea make their way rapidly into favour with loeomOH
tive superintendents, while the civil engineer regards them witb
unmitigated disgust, from their destructive effect o
way. Six or seven tons on a single wheel was, however, i
tlian any iron tyre, posseS3ing toughness enough to be safe, o
bear without spreading ; and to the employment of the hard ironi
which were resorted to as, a remedy, may be attributed many e
tlie accidents once so prevalent from the fracture of tyre& Bail-
way companies have found it much to their advantage to pofe^
chase rails honestly made of good iron properly worked, insf
of cheaper brands which proved utterly worthless. Steel t^
are not very injurious to such rails; still, a softer material is
better for adhesion, cheaper to work, and perhaps safer, 1
respects, than eteeL If a tyre could be made one, with ths
wheel rim proper, there is no doulit that its durability would i
considerably increased; not only would its resistance to spread-
ing be greater, but the shocks and vibrations to whicli it is ejc-"
posed would be transmitted to the entire mass of the wheel, in,-
atead of being more or less retained in the tyie. Under thg
present system, the tyre is exposed to a treatment nearly similar
to that which it received in the rolling mill which gave it exists
ence, the interior being nearly as much injured by the wheeL
rim, as the exterior is by the rail. Mr. G. 8. Griggs, o"
Boston and Providence Eailroad, XJ, S„ many years ago, set all<
his tyres on wood to avoid this action. The rims of the wheels
are made with dovetailed recessea all round, running in the di-
rection of the axle. Into these recesses hard wood-blocks,
thorougbly dried, are firmly fixed with the grain running b
direction of the groove. The tyres are then shrunk on, resting
wholly on the wood, which stands, say, au eighth of on inch or
less above the surface of the wheel rim. Mr. B. Adams )
brought out a far more elegant arrangement here, lie introduces
a continuous hoop spring, fitting within an internal groove in
iJje tjre, between it and the wheel Two of these hoops are, wb

Locov &m.} SPEIKG HOOPS FOR WHEELS. 1*5

believe, employed at pteBent, each about one-third cif an inch
thick and 3^ in. wida The wheel rim is turned etightly con-
Tex, and rests on the hoops, which of course sumiund it. Ex-
periments conducted on the St. Helen's Railway, lAnmishire, show
that StaflfonlBhire tyree, fitted to wheels on this system, have
given hrst-rate results when put in competition with Kruppa
steel, Swedish, and Hood and Cooper's iieat iron, fitted in the
common way. Krupp's tyres have run 40,873 miles, Hood and
Cooper's 20,798, Swedish 31,006, without requiring turning up,
fts an average mileage ; while Staffordshire tyres htled on springE,
have run 55,138 miles, remaining in excellent condition. The
engines had all 4 ft. 6 in. wheels, except the last, which had
4 ft., and their weights varied ftom 19 tons 15 cwt on
KiTipp's, to 20 tons 6 cwt on Hood and Cooper's, 23 tons 14
cwt on Swedish, and 21 tons on Mr. Adams' tyres. The saving
to the rails most be considerable, for tyres can only be worn out
at the expense of the rails. This same question of tyres nearly
concerns the prosperity of railway companies. The maintenance
of the permanent way is one of the heaviest items of expenditure
which they have to encounter; and as the destroying element is
&und in the wheels of the locomotive, every improvement of
nhich they are susceptible should be applied to them, without
regard to the primary outky, which is certain to repay itself a
hundredfold."

Smaller classes of locomotives have been introduced into con<
tractors' work and collieries, and with the best results. Such
engines are usually cheap and simple. They have mostly outside
cylinders of small diameter and long stroke, and small wheels
from 2 to 3 feet diameter. The speed never exceeds 10 miles
per hour, so that the power or tractive force is'mainly obtained
by a great speed of piston. In such engines, however, unless
the valve is wrought on the top of the cylinder, the ports are
necessarily long, the cylinder being small in diameter, and being
required to project from the frame far enough to clear the guide
bars if the valve and gearing are inside the frames. On the
manufacture and use of such engines the Meclianica' Magtmne

Liemarks ; —
" Not the least item of expense connected with the working of
^SSV "'" 'J*'^^^'' ^"7 oth« mine, is the convejimcft oi i.\a ^tc^nsA

r

I
I

I

U6 ENGINEERING FACTS, [Div. Ill,

to the place where it becDines useful The sinking of shafts, the,
erection of pumping and winding mocliineiy, nay, the very n '
ing of the coal, or ore, to the Burfetce — operations attended
they are with risk and expense in no slight degree — are, afW
all, in most caaas, but preliminary operationB, which reijuite thft
addition of a ineans of transit, safe, espeditioua, and &
before the miner can hope to reap any return for his labon^
capital, and skill. The railway station or the wharf is usually
at a considerable distance from the pit's mouth. Blast furnace^
although at first erected as close as possible to the mi
course of a few years, or even months, exhaust the veins in their
immediate neighbourhood, rendering the sinking of new shafto
at greater distances a matter of neaessity, hence the transfer a
materials to supply them becomes a matter of serious importanoe
to their proprietors.

" In the mining districts generally we see lines of railway, o
tramway rather, laid down from the pit's mouth to the whar5
the railway station, or the blast fornace, on which wt^gona capa-
ble of holding from a ton and a half to three tons, or even
are drawn in trains of two or mowi by teams of horses,
railways are for the most part of the rudest constmetion. Thi
sharpest curves and steepest inclines are considered matteis a.
little importance; contractors' rojls worn to the last, and, whei
new, of all patterns, spiked in the most neghgent iashion t(
sleepers, which are seldom replaced so long as a rait can rest on
without actually going through them, form the permanent wayt
Scarcely an attempt is made to keep the joints good, or the laUs
of an equal height; when, in addition, we remember that thtf
gauge seldom exceeds 3 £ 6 in. — 3 ft, being unusual, and 4 Qi
seldom or never met with — we are veiy liable to draw the ci
elusion that a more unpromising road to work with loco-
motives cannot possibly be met witb, even in the wilds of
America.

" On much such a, road, nevertheleaa, did steam, in the hands
of George Stephenson, commence that great era of locomotioo>
which is the distinguishing characteristic of the 19th century
hut, although railways spread in all directions around na, Uie
modern engineer, discouraged by the unpromising field, has failed
fo introduce the locomotive to any great extent, as a suhBtitnt*

I-nco. Eso,] ENGINES FOR COLLrEHY LINES. Itr

I'.ir horse Iiibour, on such linos ns George Stephenson had to (loiil
>> ith. Colliery proprietow and iron masters, believing it impos-
i 'lie to work locoraoliTes suoceasfully under the ti re um stances,
■ ri.i'er to employ expensive horee labour, contending, that any
h'antage to be derived from the employment of an engine
■^■■ luld not compensate for the lai^ outlay necessary to improve
■ \\vir roads to such an extent as tbey believe requisite to enaure
um working of a locomotive with success. In taany cases, too,
the parchase of land necessary to straighten a line woold entail
an eiiormoua expense; beaidea, rival proprietors' linos ollen cross
one anotlier, so that raising one might cause such an incline on
mother as to render it useless; all these things considered, we
'■■• apparently good reason why horse labour is still adhered to.
"Ifow, we believe that the conclusions which have led to this
■i-.jult have been arrived at too hastily, and without sufBcient
ifdeotion — without, in short, a sufficiently careful examination
into what tiie quahfications of the locomotive for such situations
actually are. An acquaintance with it only when drawing heavy
passejiger trains, at a lightning speed, on a line so perfect that
the first-clasa passenger may imagine himself passing over velvet,
gives but httle idea of the actual capabilities of suitable engines
even on the worst roads, and under the most difficult circam-
etancos. If carriiigea propelled by steam can proceed with ease,
safety, and expedition, not only on coniraou toads, hut even down,
ay. and up, our green English lands, how much more likely are
they to succeed on a road into which at least they cannot nnki
.: road indeed, which, with all its imperfections, will permit a
I ii irse'4o draw twice as much as he can on the best turnpike. The
■■■instruction of engines which will do good service in those eases,
li not a problem which presents as many diffioultiea as we may
i-jiagine at a first glance. At a low speed, carnages, whether
lirawn by horses or propelled by steam, may proceed over even
i.iie worst track with comparative ease; and, we feel certain, that
lijj'ht locomotives with low wheels, and a very short wheel-hase,
may be worked with success on almost any of the lines now
worked by horae-power. The loads to he drawn need, in no case,
I'sceed 60 tons, or the pace 7 or 8 miles an hour — 5 will usually
lie found quite fust enough for all ordinary requirements; and
is the oxistinj WB^jsoas, which iviU in moat caaea ^iMe ^w \fe

ENGIKEEBING FACTS. [Div

rl4S
icturned in active service, seldom extend 20 in. iu height from
the rail to the side beams, no possible advantage can be
by placing the engine on high wheels, which entail a great deal
of trouble in the attempt to keep the hnffer-beam low enough
to suit the waggons. A low wheel, too, insures a good blast
the chimney, by enabling the pistons to make a fair number
strokes in a minute. We believe that 2 ft. 6 in. will be foanil
a good general diameter. As to material,
than cast iron, with steel tyres. The rails iu general are cov^coi
with ao much dirt and grit, owing to their small elevation abovs
the surface of the ground, that wrought iron suffers rapid wear.

I Steel tyres appear to deserve the high character they bear, for
such purposes at least
" Too much care cannot be taken to make the bearing of sucli
engines stiff, as outside cylinders muBt be adopted, and thi
siderahle diameter and at some distance from the fi'ame, esert »
powerfal tendency to bend it ; and, the imperfections of the road
added to this, would quickly pull everj'thing to pieces
strong cross braces and plates introduoed between the frames.
For this reason, as well as another which we will refer to furthef
on, the best practice would be to adopt some such arrangement
as Forester used in his first engines — tliat is, to place the yalva
cliesta outside of the frame on the top of the eyliaders,
working the valves by means of a suitable rocking shiJt, Al-
though the engines first constructed on this principle gained th&
name of ' Boxers,' from their oscillation at high speeds, no objec-
.tion can apply to them when running at speeds under ten milea
an hour; and it was not the arrangement of the valve chests;
but of the cranks, which caused them to fidl into disfavour with
engineers. When we remember that the space between the
frames of an engine for a 2 ft 6 in. gauge is but 20 in., when
the frame is, as it should be, inside the wheels, we at once see
the great advantage gained by the adoption of any arrangement
which leaves. that space unoccupied by machinery, and permits tha
introduction of strong plates between the frame to impart tha
necessary stiffness.

" As the wheel-base is generally very limited, owing to tha
unusually sharp curves generally met with on colliery railroads,
Hie distribution of weight beuomes a verj important consideiatioi

!. ..-Li, Enc-1 engines for COLLIEnV USE3. Hn

As but four wheels ore adiuiesiblc, and they of course coupled,
means must be adopted to secure sufficient vrcight on the leading
pair for the purpose of adhesion, aa well as the prcservatiou of
the pcnnanent way, which, being weak, is quickly destroyed by
overloading a single pair of wheels. This aame distrihution of
weight is a very troublesome problem, from the fact that the fire-
box, being wider than tho gauge of the line hj many inches, can-
not go between the wheels, and, united to the weight of the foot
plat^ which must be of some size, to cany coals, lar overbalancing
the cylinder end of the engine ; the light amoke-box proving no
match for the heavy fire-hos. We have seen it necessary to
resort to a cftRt-iron buffer-heam in front, ere now, to get over
tlie diflBculty. •

" A proper disposition of the centre of gravity may always bo
secured by placing the water tank between the frames under the
front end of the engine, and hxing a la^e steam dome on the
top of the boiler, as close as possible to the chimney. Wliere a
u'lteel-base of S ft. or 6 ft. can be secured, this will invariably
give a steady engine, although it may overhang the wheela as
much as 5 ft, or 6 ft. at each end; and, in order to obtain space
for a water tank in the situation named, it is evident that all the
working machineTy must be outside, with the exception of the
link motion and eccentrics. Another advantage in placing the
vaJve chest outside will be fouiid in the ease with which steam-
tight joints may be made and broken when eaey of acce^ which
tl^ey cannot be within the smoke-box or under an engine at once
I low and narrow. The constant jolting, too, to which the cn-
^Ms is exposed is very apt to break the steam-pipe joints, unless
aiiiae elas^c arrangement is adopted.

" Ample cylinder room should be provided, to meet tho exi-
gencies of an undulating road; it is of little consequence if the
boOer is unable to furnish full pressure steam to the cjUnder for
long periods together; they will seldom exert a constant drain
in the boiler, and, besides securing economy (not, indeed, that
Uiis ia of much importance in a coal district) by working in
V'/iieral on a high grade of expansion, will, with 100 lb. steam,
,11-0 ample power for any possible exertion the engine may be
illfd on to make in ascending a steep part of the toad, &<i. ''^v,
juioir amnj' HaeB wiicb, ia general tolerably la\B\\iOTft n\\%t«

isn ENGIKEERIKG FACTS. {Oiv. Ill

two inclines nf perhaps 1 in 30 or 1 in 40, a hnndreil yarda long
oi so. Over such inclines the train, &om its slow Bpeed, pog
sesseB no impetus to aid the engine — as ttie drivers aay, ' It i
all dead pull' lai^ cylinders prevent any difficulty ii

" Where machiaery is already so much cramped for room, i
is almost needless to say that a pump is inapplicabla A So. i
GiiFard Injector is euperior in every respect; room ia easily founi
for it on the foot-plata

"Horses cannot compete in economy with liglit locomotiva
such as W6 speak of The cost of fuel ia almost nominal; ani
although we do not for a moment advocate bod roads, still we d
lint hesitate to say that in few cases need we be deterred b^
their imperfect conditioB from employing a locomotive soitaUi
to their requirements. Money will be expended to advantt^e i
improving such lines; this being done by degrees, may often I
effected almost insensibly ; every such improvement will well n
pay the outlay, by adiling to tJie durability of the engine 9n(
reducing wear and tear.

"Everything which tends to cheapen produce confers a
on the consumer. The public generally are large consumers bol(
of coal and iron, and we believe the introduction of light locoino
tives on colliery railroads a matter of some interest to the com.-
munity at large."

Amongst the most recent improvements in locomotive detaill
those connected with the tyres of the wheeb are specially deaerr-
ing of notice. Formerly the tyres in use upon various liiies v
of the ordinary Stafibrdshire description; then it was found i
"Bowling'' and "Lowmoor" tyres were not too good, that a saving
was effected by their use, even although such tyres w
more costly, until at lust we find that steel tyres are com
or leas into use, and with the very best resnlte, in both Bafet^'
and economy. Quite recently, however, the whole system
fastening tyres ia likely to be reformed. It seems anomalous
that we should be procuring material of a costly nature to reeiet
the blows to which it is subjected in the sliape of a tyre upon
the rail, and that we should also be Introducing steel and "
hardened " rails, when by other means it is possible to remove a
I* soften auch blows. TYiis \tfia ^leeu. ^iM!uii\s^ ISs. ^

;.ic... EsG.] SPRING TYRES FOH WHEELS. ISl

iiiira Bridges Adams, who hae success fully iutroJuceil a hoop spring
between the wheel and tyre. A pair of wiietsls having ordinary
Staffordshire tyres fitted to them on this principle was exhibited
:ii the international Eshibition after having rtiu 55,138 miles
i;thout turning, longer indeed than any of Kmpp's steel tyres
iLnlei similar circumstances. Such a plan seems to us a most
-i.fuonable and common sense one, and we have little doubt that if
hi.- details of &stening such tyres on sach a principle can be
II. (lie secure that they will be generally adojitod, as the saving
iiiiist be enormous.
The following data upon this subject we quote from the 'En-

"In the paper read by Mr. Thnmas Spencer, at the lost meet-
ing of the British Association, upon the manufacture of steel in
the north-eastern districts, he mentioned, as a matter of note,
tlint one firm had commenced making circular springs, under Mr.
William Bridges Adaius' patent, to be employed between the tyres
mi felloes of the wheels of all kinds of railway rolling stock,

■ It 19 stated,' said Mr. Speneor, 'that spriugs applied in this man-
:r effect an increased durability in Staffordshire tyres of 50 per
.lit. over Kmpp's cost steel tyres without springs.' We do not

xiiow whether Mr. Spencer be himself the licensee referred to,
l"r il' he be, one might be disposed to make some deduction from
his statement, but we have, in corroboration, a report from the
Hi. Helen's Railway, a mineral line in Lancashire, that Stafford-
-hire tyres set en hoop springs have run 63,913 miles under
lieavy engines, and that even then, when the engine was in to
hi} overhauled, the tyres did not require to be turned anew.
Another engine of the same weight, and engi^ed in like work,
■Hid fitted with Krupp's cast steel tyres, had come in after run-
ning 40,800 miles, to have the tyros turned down. Krupp"s
tvrea have run upwards of 100,000 miles, we believe, without
requiring to be turned, but not under engines worked like Chose
nf the St. Helen's line, upon gradients of 1 in 3fl, and around
i;urvea of 300 ft. radius. No one can doubt that the principle

■ if interposing a spring between the tyra and the wheel, in rail-
way rolling stock, is correct, the durability and security of the
application being a practical question to be settled bj experience.
IF the *fTCS ooald not be put apon spiinga without vfotYMi-j, vS

' 153 EJTGnraEEnW PACTS. fDiT. !

or in some way eiiJangering, the safety of a train, their introduc-
tion would be quite out of the question. But on the St, Hi "
line (and tliis is by no means the ouly one upon whii:h they bare
been worked), apring-aeated tyres have run for considerabla
periods of time, uuder the driving wheels of coupled engines, and;
ao far, we believe, without eshilHting any tendency indicative a
inaeourity. The speed, of coui'se, is not very high, but a me
chanical arrangement which is safe at one speed ought to be safi
at all speeds. We do not think the experiment would be a laal
one if hoop springs were put under at least the coal tracks o
other lines. If all went well, it would not then, we suppose bs
long before they would be employed — where they are J
needed — for express passenger stuck. The experieuce gained
upon the St. Helen's line points to a vast saving in the wo:
of railways, for the mere saving of tyvea la, in itself^ a small
matter. A saving of tyres represents a corresponding saving ii
rails, for the action and reaction Iwtweeu a tyre and a rail ar
necessarily equal A saving of both tyres and rails implies A
lessened strain upon all parts of the way and rolling stock—
less wear unA tear everywhere, and, conaequentJy, & saving ol
power which wear and tear upon railways necessarily absorb. T'
need not be demonstrated that it requires costly esgine power-
coke, oil and tallow, and heavy repairs — to wear oat tyres, batter
down rails, break heavy chairs in two, and, generally, knock a
strong line of railway to pieces. The priuciple of elasticity is
acknowledged in the abstract, for it is almost absolutely certain
that, without strong and yet elastic engine and carriage springs,
it would be next to impossible to maintain either way or rolling
stock at high speeds, or, indeed, to keep the trains upon the rails
at all Every railway manager and locomotive engineer under*
stands this. But in locomotive engines we have the weight of
the driving wheels, tires, driring axle, axle boxes, counterweights,
and a part of the weight of the connecting and eccentric rods, be-
sides a certain additional weight due to whatever friction tbere
may be between the axle boxes and their guides — all unrelieved
by springs. It is, of course, only the parts suspended upon the
springs tluit derive direct benefit from the interposition of springs.
In all railway rolling stock indeed, a very large part of the
veiglit in unreJieved in any way — a wev^t ■'N\iiijh. ia 'Cqe,

SPRING TYKES FOB WHEELS.

^^ lifi^ess of all dead weight. Here, clearly, we require springs,
mJ it is but the plainest conelusion from common sense that
ilie elasticity shonlil be proriJeJ as near as possible to the rolling
-^irface. Perhaps the early American 'strap rail,' a bar 2in. by
}.□., was the easiest and best perraaneat way for the very short
interval of time before it became crashed into the loDgitodinal
iiiaber upon which it rested, or, which took place very often,
iiciore the end spikes came out, and the eitd of the bar was
rijlled up by the wheels into a 'snake's head,' which now and
tlien throst itself up through the bottom of a carriage among the
Ii-^ of unsuspecting paaseugers 1 Still, if there could be such a
riling as welding iron flrraly to wood, the least thickness of iron
iriiicb would afford a good wearing surface for a rail would be
till! best, unless, indeed, it were possible to seat the rail upon
killings. As for the tyres, the application of springs appears
to be entirely practicable and higlily successful We learn that
Ibe spring wheels do not slip on the rails, but that, occasionally,
they slip a UUle between the tyre and wlieel, and tliat no prac-
tical diiadvaatage arises from this. With the wheels lifted from
the r^ls, the tyres can sometimes be slipped upon or aroand the
wheel by hand, and yet the useful adhesion to the rail is not at
all affected, and for a very obvious reason. The sUght wear of
Ihe tyros permits of their being made much lighter than usual,
other things being equal A heavy tyre ia a great evil, yet^ oidi-
iiiirily, it must be made heavy to provide for rapid wear. It is
evident that, even on the score of safety, the increased security
ai^ainst the bursting of tyres, and from the results of axles se-
verely strained by torsion, points strongly to the value of spring-
aeated tyres. The alight rooking movement which they appear
to have on the wheel is found to save the flanges from being
cut out, and yet, all the while, there is no evidence that the se-
curity of the engine, to which the tyre is applied, is endangered.
With these results we are not surprised to learn that the St
Helen's Eailway company are applying spring-seated tyres to all
their engines, as fast as they come in for examination and repair."

Upon the subject of "gauge," the "Now York Times" notices
aome of the doings of Congress in railway matters, as follows ; —

"We are shocked to observe that Congress has not apeeified
Uw Jiiaaotee of the Paoi&o ijailway oxlea — B. Bab\«A ua'd (n&^ «&.

r 161 ENGINEEKING FACTS. [Drv. 11

vastly greater importance to the safety of passengers than the
gauge of the track wliich. Congressmen do attempt to dictate, bat
which legislation 13 equally competent to pi'eaciibe. It is tru»
that physical laws have settled the principles upon which thesft
and other engineering problems are sacccssfuUy solved ; btlt'
I shall this great national highway dare to bs un^ife and espeUr
, sive when ita mechanical details have formed the subject of CoQ^

■ gressional orations) It is true that the steamship Foh Kim, 41^'
I her trial ti'ip, last week, did not ueaae to work ecoaomiCiiUy wh«

'cutting oif' short, even after they had opened Chief Engine^
I Isherwood's book against 'cutting olf' short, and solemnly l^d
I it right on the cylinder head ; but however regardleaa natoB
I may turn out to be of of&cial opinions, shall any senator dure b
I ^e a coustituency whom he has outraged by neglecting to 11
I. graft some original notion of his own — ^ood or bad, jual 1
J freaky nature is in the humour to consider it — upon the people's
I own railroadi What is the use of having any CotigreBS, if en-
I gineers, plodding in a slough of traditions and formulas — and,
I we may add, Boldiura filambciiiig over the aiiue ruaty ti'eadmilC
I' as old as gunpowder— caunot for once be compelled to turn (v
I ihort corner and conform to the supreme power of the landl
1 "Seriously, this ofUcial tampering with what is Dot profession*
I. ally understood creates irreparable mischief — worse, perhaps
li though of the same certainty, than the mischief that would en-

■ sue were a legislative body to assume the same familiarity with
f medicine that they do with engineering, and attempt to prescriba

for their own ailments. For instance, this question of railway

1 gauge. On Saturday last, Mr. Fcssenden made the fallowing

. statement in the Senate; — 'It was a conceded fact that such a

gauge (4ft. Sjiu.) was too narrow. The best roads in England

bad altered their gauges, and soma of them were 7ft. The n

I son wliy BO many roads were built on this proposed gauge was

because they had begun so, and having begun wrong, the thing

had to keep 011. But the wider gauge was safer, and susceptible

of greater speed in travelling.'

I "All of which is quite correct, with the trilling exceptions that

the only gauge iu Eughmd which has been altered is that of the

Great Western, which has to a great extent been narrowed from

win to 4£t. S^in., BO as to wotk uUaai^ sio^ wnSatva to «M-^

i'.co. Esq.] GAUGE OS RAILWAYS. 155

i.ther connecting lines; and that the wider the gauge the grestfr
ihn dangeroua weight and friction in paaaing curvea, and the less
tlie speed with a given power. As Senator Harrise remarked, it
has been proposed to narrow the gauge of the Erie road, En-
'jiTieers have estimated that this alteration could be gradually
n:coniplished at a, cost which wonid in thirty years be saved out
if repairs, not to speak of the ability to avoid transhiiiraont in
rajnnecting with other lines. With a boiler and engine as heavy
as the rails wiU economically carry, increasing the gauge beyond
the standard simply adds length and weight to the axles and all
the 'athwartahip' parts of a locomotive or car — simply increases
the load, without adding a particle of aid in carrying it. As to
■ ase in passing curvea, no gauge at all — -a mere line — would
i.'lTer no friction ; and the more the narrowest possible limits are
departed from, the greater the slipping of the wheels, the twist-
ing of the axles, and the racking of the whole structure.

"Sut these considerations are of little moment, compared with
Liie change of gauge from the common standard, to 5ft. as pro-
posed — the immense coet and labour of unbadini: uU ttm freight
from the cars of the twenty thousand miles of 4ft. BJin. rail-
way, that may happen to reach the eastern terminus of the Pacific
and reloading it upon the Pacific cars. If one principle in rail-
way management is better understood than another, it is the
yreat economy — the imperative necesaity — of not ' breaking bulk '
between connecting roads. In feet, the attempt to compel tran-
shipments at Erie, Penasylvania, by the dissimilarity of gauge,
led to actual war ; the people would not submit to the very in-
convenience which the Government now undertakes to provide

■'There arc three or fo\ir specially grave errors about railway
lr;insit with which the public is peculiarly enchanted, aad some
■) which legislative bodies never lose the opportunity of saddling
iilion railway companies, if they can get the chance. A wide
L'.mge is one. A heavy rail is another. About the time that
tlie L^islaturn of this State made use of a TO-pound rail, as one
iii the conditions of the Hudson Eiver Eiiilway charter, the best
practitioners in England ware saving lai^ly in repairs by reduc-
ing their rails to 60 lb., and even lighter, Thia ver^ com^au^
a oUfged to (fsoline more than one ecwnoifflfiti 'vta^tos*-

I

159 ESOIKEEEINO FACTSt fDm IIT.

nient and meana of safety in track, on account of this unwise
provision. Still another popular error is big driving-wheels,
We never saw an iinprofeaaional inventor or schemer in railway
machinery who did not propose about a 10ft, gauge, a 150-poand
rail, and driver, like Lord Dnndreary's Am.erican, 17ft. hi;'
and we certainly never heard of a succeasful practitioner who
did not reduce all theae dimensions, even below a standard that
is still employed on exceptional lines. In America, particularly,
and latterly in England, where the highest speeds are attained,
the size of driving-wheels is constantly being reduced, as loco-
motive economy advances. With proper counter-balancing and
workmanship, small driving-wheels and a high-speed of piston
ecouomiae both in we^ht aud in the use of steam.

"Now, the question is, shall engineers, who have made these
complex aud difficult questions the study of tbeir life, be intrusted
with the regulation of engineering details, or shall unprofessional
men, who, as a body, are not even amateurs — not even tyros-
in engineering, undertake not only to jump at conclusions which
are more than likely to embarrass this great enterprise for life,
but to compel their adoption by kw, so aa to cut off sill chances
I of remedy or reform) If Congress will just provide a teasible
financial plan, authorise the employment of the best talent in
the construction and management of the Pacific Eailway, and
then let the details severally alone, they will receive the thanks
and praises of shareholders, passengers, freighters, and the public
for centuries to come."

The expense of the maintenance of locomotives on railways
forms a very material item in their total expenditure, but with the
various improvements, such as coal burning, &c., is becoming much
reduced on lines foremost in such improvements. The present
expense of the working of the principal lines in Britain is shown
in the following table, which we extract from the 'Engineer:' —

"Allowance must be made, of course, for the greater relative
difBculties experienced by some compauies in obtaining combus-
tible, &C;, and the proportion of goods and passenger train mile-
age must i]so be taken into account. The London and North-
Westem aifleage rate, however, seems too high, all things con-
aidered. lb should be observed that the return for the Great
Wfsiern comprises the West Mi41ani,'buVTio\,'^"to9«-QftLVraliM,

Kg.] table of KAILWAY WORKING EXPKNaES. 157

f?rs-^rr« s-ffprs. t

1

i»«d»JinoDi

SsSSSSiSSglg

1 a" g i 1" S * s 5 s ?■ *

DMoipjaqnmN

aSSSggSSEiaS

awtraiiwj,

i ! i i 1 1 i i !- i ! i

rXqiraiMlFH

7,724,804
3,630,626
8.329,233
6,398,190
3.001,020
3,606.506
2.386,719

407.028
1,397.899

691,217
2,213.663
1,376,810

•wartrt

i 5 1 i 1 i !■ 1- 3 1 1 1

M 'i^lJ^* ^'UH

SBSie-lsililS

^

I ■ ■ ■ 1 ■ ' s * ■ , 5

latter unitertaking, although virtually merged in the Great
m. unfortunate];' mixed up the outlay IhgutoA Ki yc% w

1

I

158 ENOIOTlERnTQ FACTS. [Diy. iJS

rate in the return froin which our table ia compilecL" ■
Upon the same auhject another useful table of comparativeB
locomotive expenses is given by the " American Railway Tiinea,' J
the comparison being between the lilinoia Central EaiJroad an^|
the Miilland Eailway, running from Leeds to Derby, and infl
eluding the brauchea to Birmingham and Eugby. H

i

1

i

i!

jsa"sss

a

1^

Is

«iii

i

i

Si

li

1

6

i

igiiii

i

"S .

11

life

3
S
i

1

ligiil

5

1

Pi

fetasa

lili

3

II

11

lipli

1

5 !=

•si

in

ilii

s
1

p

mm

1

5

-^ /

u

Bii

i

t

n

itiils

1

&

iilli

I

—

IEno,] table of RAILWAT WOR|i[NG EXPEH9ES.

'SI;

TSS 1

gS|32

•B.JI
IF

IS.!

■5£s

^sssss

SSssi

<

" In the statement of operations of tho Midland Ilailwsy from
whicli tbe above figures are derived, the cost of cleaning incliidea
tiie wagea of ' cokemen and labourers :' in that of the Illinois
Central, tbe cost of fuel includes all handling and putting it into
ttu teii4ei ; the wages of iabourers employed m t^% a^^^ t^t W

I

180 ENGINEERING FACTS. [Div. lltM

handling material, is included in ' repairs.' On the Midland,B
one half of 'salaries aad printing' is induded in 'repairs:*!
on the Illinois Ctintral, nearly all of ' salaries ' is included iol
' repairs,', but printing is charged to another account. On the I
Tllinois Central, the pasaenget and through freight engines arefl
not allowed any mileage for switching or for standing with steam I
up : on English roads an allowance of six miles is made for eveiyfl
hoar an engine is under stefim and not inSctual service, Bring-^l
ing the Ilhnois Central mileage to this system, the total tuileal
run would probably be increased five per cent.; which wonldfl
make the total miles for live years 12,177,917, and the totalfl
cost per mile 18'43 cents. Tn reducing the mileage expenses ofl
the Midland Railway to cents,, one ptmny is as3ura.ed as equal to.fl
two cents.' ■

We proceed now to the consideration of road locomotives and ■
traction engines. The problem of a serviceable and efBcient
traction engine ia still one which, comparatively speaking, re-
mains unsolved. The great obstacles to he overcome by tita
roughness of the road render the employment of steam power a
matter of difficulty and doubtful economy. The locomotives
act of 1861 has also thrown many difficulties in the way of the
maker — in specifying the form and breadth of wheeL It will
be well, therefore, if we notice here a few of the provisiona o£
this act as given by the ' Engineer : ' —

" Any carriage containing within itself the means of its own
propulsion, pays the same tumpite toUs for every two tons of its
weight, or fraction of two tons beyond any even number of tons,
as is levied on a single horse and cart, the latter having wheels
of the some width as those of the engine. In the case of engines
of the Boydell class, the width of the shoes is to be taken as the
width of the wheels. For every carrJF^ drawn or propelled by
a road locomotive, the same toll is payable for each pair of wheels
as is paid by two horses drawing a cart, &c, with wheels of the
same width, and for every single wheel beyond a pair or piurs,
half of this toll is to be paid. In other words, for each wheel of
every carriage drawn or propelled by a road engine, the same tolls f
are to he paid as for one horse drawing a vehicle having wheels of I
width, li, however, the wheels of the carriages drawnf
ir an engine are not cylindrical, one \ia\f bwto toll is to be f

b".-o. Esq.] I,0C0M0TI\'BS ON COMMON E0AD3, ICl

Xotie of these provisioins ap|)ly to privftte niutis or briilges, uor
tu the Commercial Rnad. Engine-drawn carta not baviug cy-
liiiJrical wheels must not carry a greater load than ia allowed by
the general turnpike Act. Where the wheels pre cylindrical, «i)t
over 14 tons may be earned on a iiair of wheels of a earringa
(Iriiwn by an engine, nnleaa the wheels are 4in. or more wide,
If Gin. or more wide each jMiix of wheels may carry 2 tons,; if
6111. or more wide, each pair may carry 3 tons, but in no case,
with the following exceptions, is each single wheel to curry mure
thai) two tons, including the weight of the carriage itsel£ The
exceptions ai'o for carriages with Bptings, which may carry one-
-i\th more than the above-mentioned weights, and no restriction
f weight is to be impoeed in the ease of vehicles loaded with a
: Li^le tree, block of stone, casting, forging, boiler, or other object
.'. hich, whether in a single piece or in two or more imited together,
i'-iLTus one whole.

" Either of her Majesty's principal Secretaries of State may
I lohibit the use of any road engine which he may consider dau-
^■i;['riug or hurtful, guph pTOhiljition is to be published in tlie
'.riizelte, and if disregarded a penalty not exceeding £10 may be
■ nforeed.

" No engine weighing more than 15 tons is to be taken ovfr a
iiouiity bridge, nor over a pariah bridge when the weight exceeds
12 tons. The ownere of such engines are answerable for nil in-
jtiry occasioned by them to bridges.

" Bead engines must not emit smoke, under a penalty of 40s,
fur every day of the continuance of the nuisance.

" Every road engine must be attended by two persons, and if
mo or more vehicles are drawn another attendant must accompany
them. Two good lights must be provided for night work, ami
these are to be lighted one hour after sunset and kept burning
nntil one hour before, sunrise, whenever the engine is employed
on a highway between those hours. The penalty for neglect is
not to exceed £5.

" Engines drawing agricultural machinery are exempt from
highway tolls.

" No engine must run upon a highway at a speed exceeding
10 miles an hour, nor within a city, town, or villi^ at a
I ■sgrnA exoeeding 5 niilea an hour. The pBnaVty ^ot \oSi»,'i.'Cvi'sv

I

162 ENGirTEEEHTO^ACTS. [Di'

of this reBtriction is not to exceed £lO iii tlia case of the o

nor £5 itt the case of the peraon workiJig the engine not being

the owner.

"No locomotiT.e exceeding 7 ft. in width, nor, where the
weight esceeda 3 tons, with wlieela lees than 6 in, wide, maj
be driven within the city of London without permission of th»
Lord Mayor, nor elsewhere in the metropolis wittont permiesioa
of the Metropolitan Hoard of Works, nor in any municipal or
parliamentary laorough without permission from the proper aa-
thority. The penalty for neglect is not to exceed £5 per day ol"
such unauthorised use.

" The weight of every road engine ninst l>e It^hly marked
■upon it, under a penalty not exceeding £5, while the exiiibition
of a false statement of the weight involves a penalty not exceed-
ing £10."

The 3d clause of this act also provides, that every locomotiva
lirawing a waggon or carriuge shall have a breadth of not hxa-
than 9 inches, and the wheels of every locomotive shall bg
cylindrical or smooth-soled, under a penalty of £B for every day
any engine infringing such act shall be at work. Such a ciaose.
as this, of course, liiuits the maker to the use of smooth
wheels, and therefore compels him to have them nearer 18 inches
than 9 to secura the necessary adhesion. On the subject of the'
construction of such engines, the ' Engineer ' saya —

" We have always the fact to deal with, that on a level pave-
ment the resistance to the motion of a carriage is from S5 lb. t
35 lb. per ton, and that on ordinary roads the resistance ia froBS
T5 lb. to 150 lb. per ton. This ia exclusive uf gravity or ii
clinei), and which, on the steepest part of Holborn hill, for e:
ample, wonld^be 160 lb. per ton, and, on ineliuas of 1 in 60;;
nearly 45 lb. per ton. If a tractive power of say 160 lb. I
provided for every ton of the weight of the engine, a 6 ton e&-
gine wotdd have 750 ib. of tractive power, and at 10 miles an hone
would have to exert 20 actual horse-power. This power would
doubtless take a 5 ton carriage at the rate of 16 mdes or Sl>
miles an hour over a good road, with resistances not exoeedina
in all 75 lb. per ton. As to the jiower which may he obtained
in a steam carriage of a given weight we have tlie example ■
ete^ni Sre -engines, iu which, witti a "«e\%\it of 3 totia, a

Luco. Enc] locomotives OS COMUOS EOADS. IG3

I'f iri'in 40 to 50 Lor$(is is often exerted. With tractioii en-
giutt^ liuwever, of 10 toDs wuJgbt, we believe 50 indicattnl
hufse-powcr is abtrut the utmost exerted. There are reasoax, of
course, why a traction tsugiue, uv even a stoajn catringe, gbonld
WtiigL more than a steam fire-engine of the aame horse power,
jet the actiial iliffereuce appears to he greater than it ought.
We do not know tlie weight of Bray'a engine, but preaumu it is
JU>t far from 12 tuns. It is said to have exerted a draught of
^bpOO lb., at a speed of I ^ mile au hour, over and above its
^■ta resistance. The useful effort would be 3(i horse-power,
^Md the total work, iucluding the n:si3tanca of the engine. Bay
^Bl actual horse-powur. It is well known thiit, mth a load of
^^wdy 40 tons, any traction engine of 12 tuii^' Weight would
^^toonudsred to be heavily worked, yet on even but a moder-
^Hily ^r road the work done at 3^ miles an hour woold not
^Heeed 20 horse-power ; and if horses were actually employed,
^na dear that each might be counted equal to a load, including
^■ugon, of at least 2} tons. We have seen one of Aveling'g en-
^^BtsB, said to weigh 10 tons, take two loaded trucks, weighing
^K tous, up an iuchne of 1 in 7 at the rate of about 3 miles an
^Hm Ilei-e the total pasistance would be al^nut 3^ tons, and
^^m horse-power rather mote than 40. Tlie engine, however,
^Hdd have taken a larger load. A railway locomotive and ten-
^H: of five times the weight would have exerted ten times the
^^ber, Emd a steam fire-engine of one-fooi'th the weight, or 2j
^^■B, would have exerted an equal power (40 horses).
^^v* It is indispensable in the case of geared traction en^ea,
^^■paded to move very heavy weights, that the engine should be
^Hftvy ill order to obtain adhesion ; or otherwise, &s in the cose
^HpUeaim. Chaplin and Co-'s traction engine, that the loatl should
^Kt on the framing of the engine itselt The feathering spades
^Ktbe wheels of Bray's engines, and the cHps and studs em-
^^^ed in the wheels of other engines, ai'e for tne purpose of
^Htoining a stronger ' bite ' on the ground. It cannot, therefore,
^^Econsidered an object to greatly diminish the weight of trac-
^^BD engines, but in tlie case of steam carriages, intended only
^^kmove themselves, and from 10 cwt. to even one tou of
^Ksengeis, or perhaps one-iialf the number cari'iud in nn ordi-
^^BMtmjiiijU^ we think the weight should nol gcc^V'i <%<:Kii4

184 ENGISEEEISG FACTS. [Div. III.

tliat of steaia iire-enginea working up to iO horse-power. Ver-
tical boili^ra with small tubes, as iised in fira-engines, Eire lightet
and involve lew weight incidental!; in the way of framing and
fastening than the ordinary horizontal hoilur. The employment
of donble cylindera is, in our opinion, attended with on inci^aae
of parts, complication and weight, without a single attendant ad-
vantagt!. We are referring, at present, only to steam engines
for common roada, although single cylinders answer every pur-
pose for many other classes of engines. For steam carriages fbt
the conveyance of passengers we helieve, too, that gearing is
wholly unnecessary, and that a single cylinder connected
intermediate shaft, which, in its turn, is connected by coupling
rods to a crank axle, ia preferahle to any other arrangement. In,
atoam passenger caiTiages there will be at least 360 lb. adheaion,
of the driving wheels for every ton of the weight upon them^
and if two-thirds or even three-fifths of the whole weight is on
the driving wheels, there should he no danger of slipping,
the engine ia geared down to a very slow rate.

" Thus far wo have seen few, if any, fuaturea of steam fire-
engine practice intioduced into steam carriage construction.
We cannot helieve that steam carriages will ever give aatja-
factory results untd the present style of construction is much
modified. And many of the same changes may he profitably^
made in traction engines. One of the most successful 10 tea
traction engines now in use costs but ;£420, wliile others with.

I costly wheels, double cylinders, and other appendages of doubt-
ful value, cost from £1,100 to £1,750. Before steam can b«
successfully introduced upon common roada its application must
be simplified to the last degree of possibility."
The manufacture of the wheels is an important matter also.
The usual method is to make the boss and rim with tyre of cast-
iron, the tyre being channellecl longitudinally and transversely,
also "chilled in casting;" others, however, and the most im-
proved, snch as in Fowler's ploughing engine, are made of
wrought-iron boiler plate, 16 in. broad and Q in thick, the spokes
being secured to such rim by two rings of T-iron riveted to
each edge, the spokes crossing from the inner edge of the bosa.
to the outer edge of the rim, and vke vei'sa, they being ca«t into
He boss,

I

I

We have seen otlicr wheels Lnviiig aimilorly jilaiii scIes,
HiiJ the BpokL'3 mads uf wrought-inm gas tobing ; sach wheels
"'era I S inclioa bi'oad, and, with a lew of the rivet heads project-
ing round their peiipheries, no aljpping was experienced nitli the
heaviest loads. S^j for as the act goes, we do uot think such act
precludes the use of email rivet heads, and eveu if it did, we
know that a rough boiler plate tyre 18 ia broad, running
'fVor an ordinary roaiJ, will secure all the adhesion required in
ordinary engines of s(iy S to 10 tons weight Tiie ' Mechaiiiea'
Magaxiii^ which finds much fault with tho act, and which makes
the most of ruugh wheels, says —

■• We liave alreadj stated that the tyri-'a of such wheels are
thin ; and overhanging the spokes, as tliey ilo at each side, from
their great breadth, it is obvioua that a few days' use would ren-
der them polygonal rather than circular, as the rim would flatten
a the spokes ; in onler to avoid this, strengthening pieces,
■'strokes,' as they are termed, are fixed round the out«ide of the

e proper. The general arrangement of these strokes is a point
( which much difierenee of opinion exists ; the best practice
8 thsDi in two rows, side liy side, rouiui tha wlieel; they ace
1 lengths, generally of about '2 ft, and from 3 to 5 in.
!, and are of course lirmly riveted together on the tyre.
!Pot only do these strokes tben strengthen the tyre, but they
also serve the scarcely less important purpose of protecting it
from wear; they are themselves easily replaced when worn out,
while replacing a tyre is rather a serious undertaking. The
general practice is to leave a sjioce of about 3 iiL between the
ends of these strokes, such spaces proving of the utmost value
in retaining the clips or spades put on when the traction
engine has to cross turl^ which smooth wheels cun hardly ac-
complish.

"Now it is scarcely possible to construct a suitable wheel,
lighter or more cheaply tliitn the one to which we refer, but the
Locomotive Act renders the use of such a wheel absolutely im-
possible, if the Jaw be vigorously enforced, unless the proprietor
t'eele disposed to pay £5 a-day for the privilege ; and the worst
and most injurious characteristic of the clause is, that it will
Eiccept no equivalent for the 9 in. of smooth sole. In one of
Wi^garth's pictures, we see an electioneering pa.tt'j \«aTO\^ a. >».■&-

ENGINEEIUXG FArra.

[DiT. in.

ner with the inscription,
of Vic. 35, lap., exclaim
9 in.;' it will not suffice
if tjre surface resting t

'Give us our eleven days;' the aiithots
with equal pertinacity, ' Give na (
that we may have even double the a
the ground at one time. According t-

the framera of the bill, two 7^ in. tjrss are far more injurious
to the roitd than one 9 in. with a double load ; and the effect of
this is, that as a single 9 in. stroke will not e£fectual!y protect a
12 in. tyre. Besides greatly increasing the first cost of conetrnc-
tion, builders of this class of engine must either sabmit to hsw
cast-iron tyres, or uae wrought ones of great thickneaa, coating
about three times as much as would otherwise b

" We have no iloubt that the frameia of the clause intended tb
prevent injury to the roads. They may feel aurjirised when w*
inform them, that there is nothing so likely to injure a road a
smooth wheel; its capabilities for doing mischief &r exceed
that of the rough wheel in general work ; the reason is obvioiM
enough The only injury a traction wheel can do to a toad,
apart from that common to the rolling action of all wheels h
by Blipping. It ia evident enough that so long as a tjie b sO'
moderately luaded in propsrtion to its bearing surface, that it
does not sink into the road, that its rolling action a
paratively no liarm ; but so soon as such a wheel begins to slipj
it will cut, or rather grind away the road,

'' It is quite as much the wish of the engineers to avoid this
Bhpping aa it is the desire of the legislature to prevent the coR-
Bequent injury to the roads; but instead of permitting the u'
of a rough surfaue, to prevent this slipping, a'^d consequent abrft-
Bion, the latter compels the former to resort to a smooth wheel,
which exerts an attracting action almost continuously. Be it r
membered, that we do not for a moment advocate th« use i
spikes, spades, &c, on our highways ; such means of obtaining!!
adhesion are, except io a very few cases, not only unnecesaaryj
but positively inai)plicBble, whatever theorists, who are only
acquainted witli the mad locomotive on paper, may imagine.
HaU-a-dozen semi-spherical steel rivet-heads projecting half (»
tliree-quarters of an inch from each square foot of the tyro, wUl
give an ample amount of aiibesion tor all ordinary purposes;
wheeh go jirovided, 12 in. wide, and each loaded with 3 toiu,
jiossess quihi sufficient wihemou to ira,-*! 5

Win 1,

ESQ.] HOAD LOCOMOTIVE ACT.

r 30 without slipping, auJ will injure the ri:<<t(I^
little that they will scamily leave a mark to show where they
h<\ve goi]i> , it has heen urged that the use of oU such piMJeo
tiou^ must dig up tlie road on the same priiicijile as the roliir)'
ilt<;giiig uiocliine i such an assertion is eimply absurd ; did thv
M heals slip tiioy would certainly injure the road more than n
Binooth wheel, bat Hueh roughness effectually prevents slipping ;
and so long ob a wheel with projections of such moderate length
coutinucs to Toli, it eaii do little injury ; indeed, we must recol-
lect that the roiul is not smooth ; on. the contrary, every jiart of
il is rough, and full of iiieqiialitiea ; and into these hollo\vs and
iueijualities, such pnijections as we speak of tit without neces-
sarily injuring the road in tlie slightest dogree,

"We do not pretend to assert that traction engines are abso-
hitely hamilesB ; wti do not wish to maintain, with Boqie, tliHt
they actually improve a road ; but we maintain that, for the
transportation of beavy goods, at moderate Rjiced, they exert a
fat less injurious action ; it is easy to see that a cavalcade of
fifteen or twenty horaes with spiked shoes must do more damage
to a road than a broad wheeled traction engine trjJisporting the
aniue load, the projections on whose tyres need not be greater
than those on the horse's' shoos. So for from digging up the
roaii, these projections make but a slight indentation ; with a
properly smooth wheel the cose is dilfureiit ; such wheels slip
almost continuously, and being always as heavy loaded as possi-
ble, in the attempt to obtain adhesion, woe to the road on which
they are at work. We have seen a furrow ten yards long left
by such a wheel, where a rough one would scarcely have marked
the place where it passed.

" We thus see that this clause is calculabid to defeat the end
it had in view by its framors, and tliat it hears so injuriously
on the construction of this class of engine that it amounts almost
t" a ]irohihition of their use, and prevents in consequence the
further develnpraeiit of a principle likely to add very extensively
to our sources of transit. We believe that the matter only re-
quires to be placed before the public in its proper light, to obtain
-ueh a readjustment of the existing law as will prove satisfactory
t'l all parties."

lit coiududiqg this subjact wa cannot do beUeic tWi. ^v% tW

EKaiNEEHmG FACTS.

[Div. Ill

following acuiiratu iloscriptinn of one of the moat succeasl'iil two-

. tion-engiiie^^Measrs, Aveling and Poiturs,yet construuted. lb

' Mecliaitio^ Mugtizine,' from wliich we extract it, after soiuo [ire

liiuiiiary remurka on tbe state of roads, &o., gcwa un to siy,-

" The ttaction-eugine that was perhaps the most admirad ti;

good judges for its combined siraphcity and efficiency, aud f

it* low prime cost, the usual aecowpaiiiiiient of simplicity, w

the 'exhibit' of Mr. Avcling, of Eocheater. Its construction yr

1 bappy marriage of ingenuity with common sense. A nearl

L identical engine to the one in the Exhibition was also at wori

I at the Battersea Agricultural Show of last year. The engine i

the Eshihition weighed 8 ^ons empty, and about 10 tons wkc

full The cyliniler was 10 inches in diametei', and IS-ioc

stroke. The fire-box wjis of Howling inra, with stiiy-holts pitchec

6 inches from centre to cuntre. The boiler was flush &om ea'

I to end. A pair of longitudiiml stays placed below the tube

t were made to eouaeot the two tube plates. The fire-box wo

] lagged, and the engine was counter- weigh ted. The drivioj

I wheels could be easily disconnected from each, other, and from

V the propelling gear, by taking out a [liu uniting the boss of tlu

wheel with another boss on the axle ; this is for easily lurninf

I round cornoca. There was a powerful friction break on the driv

iiig axle, in case of need when descending an incline. Xh<

was no steam dome, properly so called, on the boUec, but t

cylinder was smTuuiided by a lagged metal jacket. This stei

I diamber is brought into direct comnmuicatioii with the etei

I ^iy meaus of liuies made in the top of the boiler, the cyliiula

I being liolted thereon. The steam thus ciccnlatea oonstantlj

I round the cyliudor, aud there b no neceasity for a steam pijMS

I The cylinder being placed close up to the chimney, the exhaurt

I pipe ia thereby very short, with its attending advantage of a

1 small bauk pressure.

" There will bo httlc tendency to prime in this engine, as tlM
I cylinder is placed as far as possible fioia the hre-bos,
I wiiere the water is most agitated by the ebullition ; the steam b
I dried by the dome-like properties of the peculiiir construction o'
[ cylinder; and on ascending incHnes, the cylinder is necessarijj
J fed with diy steam. TJie steering apparatus is very simple; i
h conaists o£ a single steering a,nd currying wheel, made to swive

^■poc. Esc!
" on its Bupi

AVELING'S TBACfnON ENGINK

Q its sappoiting rod at the ond of a light wrong) it- iron Siame
fitted to the tiont end of the smoke-box. A mun sits in fn'nt
iif the engine, guiding the wheel in his hand, and the massive
ti'action-engine belund ia literally 'led by the nose' by means of
tliia simple steering gear. The self-propelling gear consists of s
pinion on a feather at the end of the crank-asle, and working
into a larger wheel on a stud below ; on this wheel is cast s
pinion with chilled teeth, to take iji a, pitch chain, made of mas-
~i\'e iron links and steei pins. In the bracket carrying the axis
I the drum, there is a curved slot in wliich the block for the
.-lud of the small chain wheel can be made to elide. The curve
of this slot is struck from the centre of the main driving-shaft
almve. The spur wheel thus always remains in gear with the
driving pinion on the crank shaft. These were aome of the
peculiarities of the engine in the Exhibition. One of its most
iinportanl. features was the excellent construction of fire-box and
boiler, enabling it to raise the high pressure of steam for exert-
ing the great power required from a traction-engine.

" By the courtesy of Mr. Aveiing, we wore lately enabled to
see the performance of one of his peculiar traction-engines. The
engine tried was one of the several now being manufactured at
the Kochefiter Works for the Yudanamutana Copper and Mining
Company, South Australia. The mines of the company are
about 120 miles from Port Royal, and the ore has to be trans-
ported all this distance over an unbeaten tract of ground. Tlie
traction-engines have to run ten mUea at a stretch ; there being
water stations at every tenth mile. We believe that Messrs.
Aveiing and Forter an also making the fixed plant lor the sta-
tions. The cost of cai'riage is said to be nearly ^10 per ton, but
■.•n the fuel (wood) is cheap and plentiful, the traction-engines
litl probably reduce the freight to £2 per ton. In its main
iL-.itures the engine was similar to the one in the Exhibition, but
li Ldhodied several improvements and additions. The engine
'r.ail weighs, empty, H tons, and about 13 tons in working trim.
liiQ fire-box is iO in. long, 31 ia. wide, and 20 in. deep inside.
I'he fii'o-box stay bolts are 4^ in. from centre to centre. The
lioiter is 3 fL 1 in. in diameter inside, containing 37 lap welded
Mibea, 2f in. in diameter outside, and 6 ft. 7 in. long; the barrel
»nd puter fire-box bein^' of§ plates, froniEaiiDiiffle^'a'N^ti^tov^

EKGINEEKING FACTS. [Div

[17i>
tlia iiisiJi! flre-Lox is of the same thickness of plate ; the fire-box
tube pkte aud the door plate are ^ in. thick. The smoke-bnx
tube plate is a round disc ^ thick, riveted within the smoke-box
being flanged all round. The barrel of the boiler has butt-riveteil
joints and stmps, and there are two longitudinal stays
boiier barrel The whole boiler is flush, and without any angle
iron. The fire-bos is carefully lagged. The construction of fte.
entire boiier seems to come up to the best standard of locomotiviB
work, and is thus enabled to use the locomotive steam preganres
of 100 to 120 lbs. in the square inch. The cylinder "
diameter and 12 ia stroke, like the cylinder of the Exhibition
engine ; it is cast from the same pattern, and arranged im a similar
plan. On investigation, no inconvenience appeared to arise from
there being only one cylinder, as the driyer could easily take tfai
engine off the dead points by turning the multiplying gearing at
the other end. The steering gear is also the same. The working,
parts are neatly housed in from the inflnenoe of the weather.
The toothed gearing whs also covered with light cast-iron splaahera
The chief differences between this engine and the one in the Es-
r hibition consist in the mode of taking up the alack chain, and in
I the gearing being double, in order to get either two miles or four
f mile* an hour speed of traction-engine,

" There is B. pinion at each end of the crank shaft; and either

of these pinions can be thrown in and out of gear with the spur

wheel below by sliding it along a feather on tlie shaft. Tba

pinions are ingeniously kept in the positions required by

I of a simple clip or spring steel, embracing the shaft, and linetl

with leather ; it is quickly slipped off and on the shaft as required-

[ The ratio of gearing obtained by the pinions and plate wheels ia

V 1 to 20 on one side and 1 to 14 on the other. As in the 'Eshi-

I bition engine, the brass bearing carrying the latge toothed wheel

Wie fitted in a radial slot struck from the centre of the crank shaft.

• The adjustment fur taking up the slackness of the chain is, how-

F over, effected in a different manner. The brass bearing is kept

I np in the slot by a block at bottom. There is another cast-iroa

I block above, lying on the bearbig and kept down by a set-screw.

I When the bulk of the chain has to be taken up, the thinnei

f block below is taken out, and the thicker one above is substituted

stead. The bmss step is thus fixed in a perfectly firm i
f^lid adjustable bearing. A neat pUte cflNfeta m-^ *«> ^"Wwi.

AVELINC.'S TRACTIOK ESGISE.

■^ Tile ilriviug wlieela are G ft. 6 in. iu diameter, with a c(wt-iro^
11, 18 iu. wide, and a cast-iron nave 16 in. diamftt-r. Tlicre
fourteen wrouglit-inin spoies, 3j hy 1 iiL, cast 3j in. into
II.' nave, tlie ends of the spokes being tirst uotclied and dijipcd
Liiti:! tar. The nave is cost one day after tlie rim, bo timt the
■■ ■utraction of the rim may not affect the strength of the wheel.
rbe driving wheels of the Esliibition engine had blank spaces on

■ !.■ lace, in order to shp X ir^n paddlps or clijis on to the wheels
liijii passing over soft and yielding ground. In onler to con-
ini with the Locomotives Act, these openings are now filled \\[>
illi small castings, dove-tailed in, and further fastened by pins.

Tln*so castings are slipped o^ when it is wished to put in the T
]i'<iii clijis. Spikes are also employed to increase the grip of the
uliesls. The bearings are inside the wheels. The driving aslc
is of scrap iron, 5 in. in diameter. The a\le is fitted in asle
plates fixed outside the fire-bos, between the latter and the tank
i«hind. Thus, altlioagh there is no longitudinal framing, the
traction strain on the lire-box ia, in a great nieasnro, tiiken up by
the mtermediate grip oi the wliecla on tlio groimd,

" Ite weight is ehiefly on the wheels, particularly on steep
bills, which somewhat acconnte for the n^raarkahle performances
iif this engine. There are no springs, Mi'. Aveling not judging
them necessary for the slow speeds at which the engine is in-
tended to work — from two to four miles an hour. There is a
blower in the smoke-box. The man-hole is in the smoke-box
I il"? plate. There is a warming cock for heating the water in
lo tank. The loteer slide bars are of steel. The chimney is of
i-t-iron, in one casting ^ in. thick. The ends, top and bot-
: ui, of the water-tank are made of cast flanged plates, the
inought.iron sides being bolted directly thereto. The water-
lank in front of the fire-box contains 69 gallons of water; the
tjnk behind contains 211 gallons. The tanks carry coal Bnil
"Iter for a mn of 10 miles. We saw 'No. S3 ' marked on the
\ iidananiutana engine, which evinces great success in the sale of
I iction -engines, as we believe tliat the firm tJ>ok up this branch

■ 1' ilieir business only three years ago. The price marked on the
iMigine in the Exhibition was f 420. On account of the one tried
being made with a larger fire-box, double gearing, additional
vfttbet-ioB^ iiO; tlus piu» itaa heen raised to £&^Q.

r 172 ENGISEEEING FACTS. [Div. IH.

" The traction-enginea uow uiakiiig for South Australia are
[' itttendeii to draw a train of aboat six waggons. Each waggon is
strongly built of oak, and ia on four wheels, tlie front wheels be-
ing 3 ft 6 in., the hind wheels 4 ft. 9 in., in diameter. The
I front wheels can swivel, and there is a light h'on coitpling between
I each, waggoa At the late trial of tliia traction-engine the roada
I were ill a yielding, sloppy state, from the effects of the ■weather;
I the ntud formed a oomplete labricating material between thfl
I wheuls of the engine and the road. At the same time, to prevent
I any injury to the road-stuface, the clips were not applied to the
I driving wheels; a few spikes only were inserted in the rims. Eadi
[ wa^on, when loaded mt\i laige baulks of timber, weighed nbont
[ five tons. We saw the engine take five waggons up indinm
I vatying from 1 in 12 to 1 in 8, at speeds varying from four mHea
I to about two miles an hour. The engine ran 7 miles iu about
I S^ hours, and consumed about 3 cwt. of coaL Probably, no trao-
r tion-engine, of the some weight, has ever accomplished so much.
The engine, with its train of four coupled waggons, passed some
very sharp corucra with great eaee. This is oas uf the great ad-
vantages of an engine over a train of horses, as in turning comers
only one or two horses are able to pull properly. The hiasiug of
the steam certainly frightened some horses on the i-oad. This is
one of the impediments to the more genera! inti-oductiou of
traution-engines. We know, however, by our own experienet^
that horses very soon get accustomed to the whistling of steam.
" It is well known that the resistance offered by the aurfiica of
common road to the motion of a vehicle is in a direct ratio to
leloadj is in an inverse ratio to the diameter of the wheels j white;
I the resistaQGD is almost uninfluenced by the breadth of the wheels.
n speeds the resistance is almo'st independent of the velo-
I city of the vehicle. The co-efficient of resistance, however, varies
I so much with the state of the road (according to ^Moiin, about
I- &om 1-1 3th to about 1-60 th of the load), that it would be scarcely
I possible to estimate, by calculation, the precise tractive power
I exerted by Mr. Aveling'a engine. Suppose we compare the trao-
I Koii-engine to a team of horses; neglecting the power exerted in
I moving itself, and only taking into account the four loaded cara.
I Each car weighed with its load about 5 tons, v/iih wheels averag-
' J 4 A. ia diametei', and i\ in. in tyres. Considering the bad

L<KO. BrG.5 tWAtS Gf ESeOTJS AT TTOBCBSTWl SHOT. ITS

state of the sutface, we may take the cr>-efficii.'nt of n^tii^tance on
the road at l-20th of the weight; aod the four curs weighing
together 30 tons, the reaiataDce on a dead level would thus be
1 ton. To this would be added 3 tone for an incline of I in 10,
making a total of 3 tons for four waggons, on an incline of 1-lOth,

" Perhaps the most accurate means of learning the available
tractive power would be to uae a strong dynamometer, simi)at to
the one employed by Mr, Fowler for ascertaining the draught of
hia MK-furrow eteam-plough.

" We believe thut we may congmtulate both Mr. Aveling and
liis customers on the results of the experiments we lately wit-
nessed."

It may he probably as well to append to this seoti(.*n the fol-
lowing account of the trial of portable engines which took place
last year at "Worcester Royal Agricultural Show.

The prizes offered by this society were for fixed engines not
exceeding 12 horse-power, liiO, and ^10 for the boilers of such
engines. For portable engines j62^not exceeding 8 horse-power,
and £25 for those exceeding 8 horse-power. The nature of the
leeta were aa followa, and were instituted principally with a view
to determine the quantity of fuel consumed. The judges were,
Daniel Kinnear Clark, Esq., C. E., author of the well known
work on Eailmay Machinery ; G. V, Goooh, Esq., C. E. ; and Mr.
Stewart of the Midland Sailway.

The portable and fixed engines were arranged on the ground,
and the former had 7 lbs. of coal and 1 lb. of wood per horse-
power, carefully served out to them ; the fire being then lighted
and steam got up to a pressure of 50 lbs. per square inch : the
whole of the coal in the fire-box was then taken and weighed,
the weight being deducted from what was served out at first, so
ds to enable a correct estimate to be formed of the amount re-
quired to raise Bteam. The driving-wheel was then placed in con-
iiHction with the pulley of the friction dynamometer (which was
made by Messrs. Easton, Amoa, being an improved form of De
I'lon/s friction brake) by means of a leather belt. The engine,
■ms arranged, is now required to exert its force upon the Dyna-
iimraeter, whose number of revolutions are registered by a counter,
iiid is allowed to run as long as it will turn the brake at the
nquired speed. When the engine is stopped a aeoottd ^rtvaa.

r

I

I

ESGINEEEiNG FACTS,

piv. II

of fuel is aervetl out, when ateam is agiiin raiaeJ to 50 lbs. pei
aq. ill. Every means are employed in stoking to keep up e
as long as possible, and the fuel ia broken up into small piece^
not lai^r than a small her'

When the engine has eshauateil its power a second time, tbfl
number of revolutions of the brake are noted. The speed of th<
tirake is nbtaLiied by the relative proportions of its pulley an
the driving wheel of the engine, the number of revolutions <
the latter being known. The load on the brake or engine is detei
ininpd by the nominal power of the engine multiplied by 33,001
and divided by the circumference of the centra of effect of t"
lii^B proper or collar, multiplied by the number of revolution
of the brake wheel per niinule. The duty of the engine is o
tained by dividing the total number of revolutions of the I
wheel by the number of revolutions of the engine per minutl
The conditions of the engines competing were very numerous tbi
most important were ; Of the portable engines it was reqniidl
that the 8 horse class shouIJ not exceed that power, nor have i
cylinder of greater diameter than 9f in. ^o lixed engine Bhoali
exceed 10 horse nominal power, nor have a cylinder exceedinj
11 i in. The engines were required to ite submitted either befbn
or after trial to a complete examiiiation of their valves, pistons
and other internal fittings, so that convenience of arrangement
might he considered by the judges along with the working efil
ciency. The tubes in boilers wore not allowed to be smallet
tiian 2i in. inside nor less than No. 12 W. G. thick, the tnbea
to }ie spaced not closer than 1 in. clear.

The following table exhibits the results of such trials ;-

FIXED STEAM ENGINES.

lis"
ihi ■

(■8S
B-04
G'51
7-10

Burett, BchaJ], uid Amlieva
Clayton and SLattleworth..
Sonisb; knd SooB

inf and Sons

aadWbiit»iei

asa7\ * \6t-s\ \o'? a\

I

TABLE OF BE8CLT3 OF TRIALS.

a

¥4 i

■amaoa
}0 9auj

^iSSsI sign 8 a istiti 8

^Vqj^'

liSsl K!K ^ 1 i!!iS§ 1

■"qi "!,

a

I

i

Hi

1

^32223 ..... .. . .,-..3'. .

1

^KiSs Silll s 1 !""l"l 1

CSS

SSSgS BSSig E s gsssss !a

■BoiSng JO

23SS3 -™ - - -»--- .

3ll3o[»iii3

Pill iPP i i PiEli i

i

t

i

11

II

t

1

jl

:-i

1'

si

i

S ;

■311

II

n

Jj

1

i

J

3

1

1

1

1
^1

i

if

1
1

B might be en

1 for trift] by

r words, vn.

f,UlC mater

pposed, nearly the whote of the enginpa suL-
tho nrnkera were specially constructeil engines,
m " racers." This waa fully corrohurateil by
3 relueing tu have Uieu cuuimeimX «

I

I

176 ENGINEERING FACTS. [Drv

tiieil against such " racers ;" some ileclariiig that their otlier e
ginea exhibited at thoir stands had no pistons. One firm onlj
we heheve, consented to the trial, at least had no objections to con,
sent; this was Messrs. Brown and May, whose engine, owing fa
some slight noncnnfomiity in the tubes to the ruli?s of the society
was disqualified for the pi'ize list. This difference in tho tahc
(being outside measurement, we heheve, in place of inside) ga;n
the engine no advantage, although it nominally preyented then
gaicLug a prize.

Many important improvementa have been introduced ij
department of engineering manufacture in the few past years
these, however, ,ha¥e been chiefly improvements of conatruction
no decidedly novel arrangements having been introduced,
siderable amonnt of locomotive practice, however, is becoming A
seminated among the makers of portable engines; such praotio
illustrating itself in the shape of good boilers, well-stayed f
boxes, and general good propoi'tion nf the working parts.

MARINE ENOIHKB.

Progress in this department of engineering has during t
past few years been exceedingly slow ; indeed, no decided adv&no
has been made. Some attempts have been made to introduce si
perheaters, but without nmch success ; in most cases the supw
heaters have become bnmed out, and in others it has been found
that surcharged steam has a decidedly injurious effect u^
indeta. A plan has been adopted of Wethered's to temper ti
eiiicharged stoam with saturated or moist eteam, so as to prevent it
injurious effects upon the cylinder. This also has been abandonej
Surface condensation has been revived, and worked with a
to facilitate the adoption of high pressures ancillary to expaaain
working. In t)je engines the combined high and low j:
system seems to have made much pi'ogress, and this especially ii
thelmndsof the enterprising Glasgow engineers, Messrs. Bandolpl
& Elder. Mo^t of their engines are constructed on this b'
patented principle. The engines are usually of the inverted c^
inder or hammer description, adapted for screw propulsion. Th
high-pressure cylinder is placed in a line with the low p
cylinder, aud at right angles to the crank-sliaft. The lew pressuii
cylinder has four times the area, oi &e \wg^ ^vesaure cylindee

rth<

^^■wn

■1!.] IMPKOVEMESTS IN MARINE EKGISKS.

"mJ is placed immediately ovef tlie CBntre of the erank-pin. The

twu eylindets ara connected by an intermediat-e or side lever, a>

Hi»t wliila one piston ascends the other descenJa, and vire versa.

The low-pressure cylinder is directly connected to the crank by

eonn^cting-iwi, and the high-presaure cylinder pieton-rod is

ied right down into the air-pump, which is placed in front of

ii&ce^condensar. The two cylinders are jacketed with high

m completely round and through both covers and

The boiler pressure is from 30 to 40 lbs. perBqnare inch,

being admitted to the high-pressure cylinder, where it

off and expanded four to six fold ; such engines have given

resolta, and have reduced the consumiition of fuel to as low

;2 lbs. ■per indicated horse power per hour. They are, however,

iwhat complicated engines.

'easts. Humphrey and Teunant have recently patented some

acting compound engines upon the combined high and low

principla The small, or high-pressure cylinder, is

the same centre line with that of the low-pressure cyl-

into which the steam ia exhausted. The low-preasure cyl-

occupies a place immediately in front of the high-pressure

ider, and communicates its motion through the medium of u

to the cmnk.

B general problem in marine engineering to be solved seemi^
one of economy, not only in fiiBt coat, but in dead weight, n-s
economy of fuel, fur this oonatitutea the greatest dead weight
in aliips bound for long voyages. The 'Engineer,' speaking «i
marine engine economy, says, "The problem of marine engine im-
provement has not, however, been finally solved, and there arc
itigns even that wo shall have to retrace some of the Hteps
taken in this direction, at least should no timely remp'ly
ivered for some of the evils which have alwady appeared
with the refoiined practice. In this we do not in-
the failure of high-pressote boilers, fur steam of much more
40 lb. has not yet been adopted to any considerable exU'nt,
ugh the attempt to introduce a pressure of 130 lb. in con-
with surface condensation has already resulted in a lat^e
of the Mediterranean companies. It is certainly sin-
with distilled water, a high- pressure boiler has not
ladc to irodc properly at sea ; W\i "«b»si vi* to Akbrk

f

I

178 ENGINEERISG FACTS. [Div

the estraordinary example of lioiler-makiiig employed in
attempt just referred to, there would be no wonder nt the result.
The failure was doe, it would appear, to defective oireulatiini,
and to ihat alone. It is strange that the locomotive hoiler, with.
the cylindrical fire-box of Mr. Allan, has not yet be^n tried at
sea. Thia, we shonld anticipate, would answer well. Ramsdcn'
high-preasure boiler is understood to hayo given good remtlts, and
considerable expectations have been raised by the description of
Inglia' high-pressure marine boiler, which, we understand, is being
tested in the north. Speaking of water circulation, it 1ms been
stated that the injector has been successfully employed apon
some of the Woolwich boats to transfer the boihng water from
one part of the boiler to another. It is alleged that boiling i
may be readily forced by the injector if the source of supply ba
above the level of the instrument. In taking boiling water under
pre£siire, the effect of the latter, as assisting iu the movement, ii
to be considered It has been denied, we should aay, that tha
condensation of the steam passing through the injector is essen-
tial to its action -J and it ha$ been observed that, if the imiteil
jets of steam and water be directed into the open air, the s
disengages itself from the water at a short distance from the point
of discharge, and rises by itself, to condense immediitely in K
visible cloud of mist. Some such result, indeed, was to have
been expected, from the known large quantity of sti-am p:
through the injector in performing any given amount of work.
We introduce this subject, in connection with marine boilera,
it is possible that the injector miiy yet he found to serve other
purposes than that for which, thus far, it has been almost exclu-
sivBly employed.

" As for superheating, anything beyond drying the steam ia<
found to introduce practical evils. But for these, possibly, enperr
heating would have been long ago generally resorted to. In tbfr
old days of boilers working at or below atmospheric pressure, on*
Ttiomas Saint (specification No, 2,670, 1802) proposed to emjJqr
a self acting valve, thi'ough which, whenever the steam fell be*
low the atmospheric point, hot aii' might enter from the fira
directly into the steam. In 1809 William Enghsh patented tlie
application of superheaters to steam of about 237 deg. tempera-
tam, thereby expanding it ao us to \'(OTk with increased eSuct

SUPERHEATED STEAM- 17tt

tlie cylinder of tne engine. Englisli propoaad to use m a supoi^
lieater a ' tube or tubes, or otlier ajiprofiriate vesaels or recei>-
taolea,' Ilia deaeription pointing to iron tube* lined with brass iir
oopper. He contemplated a red heat ' when required,' and this
intensity of tenipciuture, doubtless, proved the rock on which lila
Mbeine was wre::ked more than half a century ago. Ut: patented
the use also of superheated steam for drying purposes, and the
fate Bryan Donkin took out a similar patent in 1816, and the
same thing, we believe, has been sHveral times patented since.
Trevithick had heated his steam cylinders by means of a separati!
lire, and with good reaultii as far as the mere economy of steam
was conuerued. The late Mr. Ifolici't Stephenson stated on one
<i<jcasion that it was from a communication from Trevithick that
lie was first led to place the cylinders of the Planet locomotive
within the smoke-box. In the same year that this was done,
I'iz., 1830, Dr. Huycraft took out a patent relating to superheat-
ing. TTia speciiication contained a blunder much the same in
kind as that which Woolf committed when ho declared, in 1 804,
that tbe steam of 40 lb. would expand forty-fold before falling
to atmoapheriu pressure. Dr. Haycraft asaerteil that by super-
lieating to 100 deg- above the normal temperature of steam it
waa expanded ten-fold, and the consumption of fuel for a given
power dirainisheil by nine-tenths. He, too, proposed to employ
the cylinder as a superheater, by surrounding it with briokwork
and applying fire to it. Surcharged steam, he stated, * had
heretofore been attempted to be used in steam engines, but with-
out any success,' as it burnt up the lubricating material and
destroyed the packing — exactly aa it still does in our own prac-
tice. The Dr. projiosed a contrivance, of no great probable
merit, for preventing the evils of superheating, and he insisted
upon the employment of metallic pistons instead of hemp packing.
The most creditable feature in his specification was the employ-
ment of a small high-pressure boiler in addition to tliut working
at low pressure, the steam from the former being passed througb
II ^teara jacket around the cylinder, and afterwards discharged
through a small loaded valve into the low-pressure boiler. The
Tloctor particularly pointed out the object of preventing cmiden-
-ation within the cylinder, 'which condensation by the suljse-
HHBiA evaporation oociuions an abstraction ut \\ea,t uu^ ^ vu\is£r

ENGINEERING FACTS. fDiv. III.

qnent waste of steam.' Most of his sehemea anticipated a num-
ber of aubaequent patenteea.

" Superheating was not abandoned, nor did it, either, make
much prt^reea In 1847, Moaes Poole, in a specification, referred
to the long experience of the loaa of heat by condensation within
the cylinder, and again proposed superheating. As the difScuI-
tiea attending the use of very hot steam were well understood,
Poole proposed to temper the heated steam witli ordinary satut-
ated steam, and with the help of a thermometer to maintain a
workable temperature in the cylinder. This, of courae, inviili-'

,ted Wethere(i's subsequent patent for 'combined steam,' ol
which so much waa heard five years ago. Since 1858 supeT*
heating has been resumed, and hot steam has been largely worked
in marine engines in every part of the world. But in the cas4
of ihe Holyhead and Kingstown boats, it has been found ne*
ceaaary to return to the old mode of working, with saturated
steam, ajid although the iron tubes of superheaters have been
generally made J in. thick, the Peninsular and Oriental Com<
pany have found it necessary to abandon iron superheaters albh
gether, for the preeent, others of copper being employed in then
new ships. In the practice of the leading engineers, MesanL
Penti, for example, a 'dryer' onlyis now employed. Steam, as it
ordinarily escapes from boilers, generally carries more or less apiay
with it, and there can be no doubt of the advantage of completely
converting this into good dry ateani. Meaera. Fairbaim and Tait'd
experiments on the density of ateam showed that, even where it
was produced in small quantities, and with every care in the eon'
structiiin and management of the apparatus, it carried moisture away
with it from the water. This waa proved by superheating it, wheii
it was found that the expansion for a few degrees above the poinlE
of saturation waa three timea more rapid than that which oc-
curred at a higher temperature, under which the steam followed
tlie usual law of gaseous bodiea, expanding about jj^th of iti
volume for each additional degree. To bring the steam wholljf
into the gaseous state, and even to heat it a little farther, it
well enough; especially when we know that, without S1lpe^
beating, many enginea are worked regularly without any othei
tnbricnnt in the cylinder than that supplied by the condftnsoil
u itneW. As for the mode nC m^CTHpB.t\n5, it is not imp

lot LIB^OI

SURFACE fONDENSATHjS,

hahlo that the bent of any is that proposed li^' Haycmftr
nil, tiiivelupiag the cylimitir with eteam of a faigbei* presBurt
tliau that worked within it, enipluylDg a email gnpplem«ntary
huUer for the piirposp, as is ni>w done on some of the Coiiudimi

"Aa for surface Bai]ilt.'nsatio(i, it cannot be dviiied that a
corcoeive action has been nmnifeeted in boikrs fitted with eiu-
face CDudenaers, in some caaes to such an oxteut th^ the boileis
are rapidly destroyed. So, too, the brass or copper tubes of the
eoudeiiaer have been aometimea fuuud to disintegrate tu such an
extent aa t« cramble to pieuea within a short time. In America,
where surface condensation has been extensively practised, some
moat striking and, indeed, unaccountuble, cases of this kind have
been reported."

In writing of marine engine luipravement. tlie ' Mechimicn'
Magazine,' comparing the marine engine ivitli the locomotive,

" Suarcely any class of engine baa undergone the same
amount of improvement &6 the locomotive ; comparatively an
infant in years, it shows all the science, culture, and physical
development of the full-grown man. All the resources of science
and the refinements of art Imve been lavished on it; always ail
attractive subject to mechanical minds, from its extreme beauty,
its exquisite simplicity, and its vast concentration of power
within the smallest limits, it haa, perliapa, during the few years
which have elapsed since the ' Rocket ' first astonished those who
gazed on its till then unparalleled performance, received mure
attention than almost any other form of enginu ; its powers of
bringing ileelf before the public have Iweik unrivalled, and,
themfore, it has met with world-wide attention. Elaborate
treatises have been written on the minutest points connected
with its phystque; its anatomy studied with a skill worthy of a
liuuter, or a Cooper, and as a result we have — tlie modern loco-
motive, a machine before which admiration becomes dumb, and
oven praise sinks into silenca"

" The great cause of locomotive improvement haa been the

B scope hitherto allowed, to both the builder and desiguer, for

exercise of their respective talents; certain restricliona

taitHU^ so tii&iag aa acarcely t>o uusnl Ui.« XkBiou^ w^iv

ENGINEERING FACTS [Div

rl82
jilieJ with, they moj follow the full bent of their iticlinatious^
tmd introduce anch alterations as their es]jerionoe may suggest ai
likely to prove not only alterations, but improvements.
" In many cases we find, too, that, from the skill and atten-
tion of locomotive superintendents, particular classes of locom<h
tives have derived certain peculiar advantagetn, which cause thern
to stand high in the opinions of the engineering public Gifte4
in most cases, with considerable attainments, and carefully
trained in the practical routine of their professions, aU such ii
required were the means and permission to carry out such et
periments, anil make such alterations as they considered would
effott improvements. Directors willingly granted the permi»
(don, aharoholders eagerly produced the pecuniary requirementa
necessary, and, as a conseiiuence, locomotives nf the most varied

» construction were turned out from the workshops all over the
kingdom. Experiments could easily be entered into; no diffi-
culty could possibly be experienced in tiying a new engine, even
although it was like nothing which had gone before, and in-
volved the newest and strangest featuiissj for risk was merely
nominal, the cost of an engine seldom exceeding £2 000 i
£3,000; so thatj even if the machine proved an utter failan^
and found its place in the scrap-heap instead of working the Uiw%
it was a matter of little consequence ; no risk of life and Umby
considerations far more imptortant, being involved, it was jnot w
safe to travel a hundred miles with such an engine as with o
of the ordinary trains; indeed, we find that many of the most
valuable resulte we possess have been obtained from experi-
ments conducted with ordinary passenger trains in the osual
course of bus

I" Hanking before the locomotive in economy, though second'
to it in importance, we have the Cornish engine — ^a niacfaina
which approaches nearer to theoretical perfection than almost
any other which man's ingenuity has enabled him to construofc
Uere, again, we see the result of genius untrammelled by o
ditions, either dictated by circumstances, or, worse still, by a lay

public. The designer, totally unfettered, devotes all the energies

^^M of his well-trained mind to the subject, and regarding the
^^B chine in the abstract, instead of the positive, brings it to such
^^Jperftction [Jiat we find a consumption of a coutile of poundfl e

Em;-] IMPKOVEMESTS IS MARINE E.VGISES. l«:l

twal per hour gives ua a horae-power. How liiiTerent in all re-
spixts is the history of the warijie engine from either that nf the
/rwomotire nr the Cornish ; it is a history in which we find little
but u constant war between theory and prai;lic« — a perpetunl
fertruggte, on the part of the engineer, to make that which was
Bght expedient aa welL The result has been a class of engines,
Btevy, bulky, and expensive, both to purchase and use, but pos-
^kdng the one advantage, which, up to the present, at least, is
HpisiJered to compensnte for the want of every other, they are
^■Efoctly trustworthy.

H " No improvement in the marine engine is likely to meut
Eith universal, or even partial, adoption until it has been
■horoaghly proved by a sraies of esperiments, conducted on a
Bre&t scale, by able men; until, in fact, the engine has under-
Bpne tlie same thorongh examination as the locomotive, we re-
Hiet that at present we see little chance of any great underlakiog
^Kthe kind likely to lead to useful results. It is true that, in a
Kv ctiaes, we see engines embracing many novel features taken
^pto favour, but such cases are too rare to infiueuee the publii;
Hmd to any considerable extent. Experiments assume a very
^pav« aspect indeed when they are performed on a machine cost-
B|g tens of thousands of pounds, and tni the successful working
If Avbich depends, it may be, the lives of huuilreds of our fellow-
^pBaturea. The breaking down of an engine, the leakage of a
H^ler, hae, ere now, alas, too often carried desolation and misery
H m&ny an English home ; rash, indeed, would be the man who
Hpuld for a moment advise euch a departure &om precedent as
nould introduce a single element of extra risk on board a steam-
^bip ; hence wo find old plans and models of engine adhered to
Kith a tenacity of gripe which the hand of science has hitherto
Ipoved too weak to unloose. Let us ask ourselves, how long
Bm this state of things continue; and, supposing we are dissatis-
Hpd witti it, to what quarter are we to look for an initiative in a
^Bange for the betterl Tliexe questions are doubtless full of
Hpportance, and worthy of the most serious consideration, not
^■lly from the engineer, but also from the public at large.
B " The general practice amongst steam shipping ownci'S is,
^bien giving an oriler for an engine, to go to some lirat-class firm
HflQ]uated foi the constrnction uf the piuticular clasa of en^ne .

f

I

I

EVGINEEBINC FACTS. IDif. in.

they maj i«qu>t« ; and tbia firm would no more deput fi«B Ifas
urdinaiy style of engine on which their leputatioii testa thaa tfa^

uld bote holes in the Teasel and send her to the Uitton.
deed, the certainty is that any attempt at the inbodnctioD of m
decided novelty would be as atoutly resisted bj the owneiB
the actual scuttling of the ship, With all our dedre to a
advance, we cannot but admit that such piindples a
correct in the cose of ocean ateam-ahips. Certain forms of e
gine a long series of years have proved trustworthy, and tlie k
')t the ship and all bands, or even a consideraUe delay od tier
voyage, would be badly compensated for by the eaving of a lei
tons of coals, or the use of a smaller engina Such steamers anr
i^uite unsuited for the first embodimeut of a crude idea — cnidia^
because untried. Nor does the Xavy offer a much better field.
Such ships would badly fulfil their purpose did they break down
fur from home, perhaps close on au enemy's shore; but^ forto-
naltily for the ends of science, all necessary opportunities are still
afforded to the engineer by the large class of vessels which carry
on our home trade, making short voyages from port to ]>oA
Such vessels can rarely encounter any risk comparable with the
uceaii steamer, and otien belongii^ to companies, who give al-
most uuliniited powers to Iheir manager, who stands, indeed, in
nearly the same relation to hia employers that the locomotive
superintendent does to the board of directors. In such situa-
tions, u)on of talent and enterprise can do much ; and, although
tied up in many respects, they have nevertheless every reason-
able opportunity for experiment ; the ships vrith which they
have to deal are gBneralLy of moderate size, and making but short
voyagBB little danger is run of a breakdown, which is very un-
likely to happen, because the ship spends so much time in port
that every opportunity is afforded for the most thorough examin-
ation of the machinery.

But, granting that we have thus a sufficiently numerous class
of sluuiuera ou wliich to conduct experiments, in what should
thvHU i>X[)erimenta consist 1 Wo reply, in the first place, that,
on board a steamer, an eugiue on a perfectly new and untried
principle should never be made the subject of experiment.
We have known such cases where the only result obtained by
fi ivali/ oJevor thing was loss of money, risk of the ship and

\UKINE Eno.] improvements in marine engines. 1R5

crew, and the creation of auch a disgust for onythiag uoiv il
'>}ie minds of all connected with tlie ship aa led to the engine's
being ignominionsly removed, and replaced by macliinery which
could be depended on, although inferior in all other respects to
that rejected. All such engines should be carefully tried on
ahore first, tried for many days in constant work ; carefully tried
afterwaiils when on board the ship on the re^lat trial ground.
Many things will be found to require alteration and improve-
ment and the result wiU most probably be u vessel which wilt
pve perfect satisfaction.

"In making use of the word 'experiment,' we do not mean
the conducting of a series of observations in order to obtain
certaia iniormatiun which we require relative to the working
uf any (larticutar class of engine ; we mean that every engine
the construction of wliich involves any novelty of principle or
working detail, is in its first nso an esperiraent, and reqaires
careful testing ere the Hves of passengers and the ]>roperty of
public companies are suSei'ed to depend on its successit'ul working.

" The question only remains, to what quarter should we look
foi Buccesa I The answer is obvious ; uo further economy can
be obtained in steam power without the use of high presaimi
and expansion. The theorist who proposes such schemes may
tind fault, and complain of the tardy adoption of his ideas ;
lint he should remember the difficulties which beset the marine
Lingineer in every attempt to make what is theoretically correct
practically correct also ; that the possibility of doing so exists,
is proved by the great comparative success which has alreaily
attended the labour of many of our junior firms ; and we feel
little doubt that from such men the subject of steam propulsion
viiW meet with aucli sound attention as must, in the course of a
few years, lead to improvements which wiU niolto the marine
iank with either the Cornish or locomotive engine in economy.

Again in another article it is stated, that " such engines as
the ' Lord of the Isles ' or the ' Great Britain ' locomotives, have
(in many occasions exerted as much as 800 indicated horse-
power, in rogidar work. If we neglect the weights of the lead-
ing and traihng wheels, springs, &c., as being only necessary to
the locomotion of the machine, not to the mere exercise of its
power, we shall find that any of them weigh coDsiderabl; under

ENGISEERING FACTS.

(Div. Ill

I

40 tons in working order — tliut ia to saj, with tlie boiler full
and the driveia retained as fly-wheel& Ifow 40 toaa dlTtdeC
into 800 horae-power, givea na 20 horae-powei' for each ton n
dead weight If we regard 800 horse-puwer as au abnorma
effort, which, if long continued, might lead to the injury of tlia
machine, and only coneidor the moximnni of efTect as 500 horm-
power, we have still over 12 horse-power for each ton. Now,
the best practice in marine engineering has hitherto failed ta
reduce the weight, of diiect-iicting engines, with tubular boile
and injection condensers, to leas than 12 cwt. per horae-pow
nominal; and aa the mdieated generally esceeda the ttominil,
ftbont three times on an average, we may safely aay that e
of the marine machiniiry in daily nse prodnces but 6 1
power, while a firat-claas locomotive can produce 1;
the greatest ease, and even 20 under exceptional circumstaneeft
such facts speak for themselves, and ought naturally to lead ll
the consideration of the means of procuring equally good lesotti
in both cases ; the first effect of which would be to place at ott
disposal a, cIrbb of vessels possessing all the speed, and two
three times the cargo capacity, of the 'Persia,' for i
without any increase in' her si^e. Such vessels could not fail tl
prove more highly remunerative to their owners than anythinj
which has gone before ; and it is sufficiently remarkable that m
trials have ever been made with steamships fitted with screti
propellers and small engines of the locomotive class, running al
locomotive speed with high -pressure. We can only attribntf
this supinenesa to the small interest which companies generally
take in mere engineering concerns — meters which they usually
trust wholly to their superintending engineer, who, having all
the risk in ease of failure, and but little prospect of reward ia
case of success, is commonly well satisfied to do well, without
any desire to risk reputation or prospects in the attempt to do
better. Neveithelesa, the reward held out to shipownei
mi^nificant, and it is high time they bestirred thomselvt
obtain it."

Much importance attaches itself to the manner in wliich marina
engines are constructed, and this in particular to the fitting of
brasses and bearings, Sea. On this detail of the marine engine the
'Sdenfijie Amenccin' makes the following practical rem.irks;-

■BuneEno] brasses and bearings. 187

■"So little attention is given to thia snbject by peraone who
^nit to know better, and so mnch indifference is miLnifested to
B resulta of neglect, that we have felt it important lo cnll
Bjaition to the subject, and, by pointing out the canpps iif ilis-
Br, bring the matter to the direct attention of all interested.
Hty ateatn engines have be^n disabled, and the safety of the
Mongers and cai^o iniperilletl when cm ship-board by inatteii-
K to the condition of the bearings. We have onrselves suen
■rge beam engine slowed down and ftnallj stopped entirely
■it tlie cause alluded to — so hot had the beam centre (the part
■toed) become, that the utmost efforts of powerful men anil
Bh^ sledge weighing some twenty pounds were unavailing to
mjk off the nuts which held the 'binder' down. As for im-
wwing the nnta in the legitimate way — with a wrench — that
mk out of the question ; a three-fold block and luff tackle would
Bdly have started them. In the case alluded to, the diameter
Kihe centre was perhaps 14in., bj about 20in. in length, and
■bough for thirty minutea previous to the disaster everything
Wk working properly, so rapidly did the bearing heat up that,
■otattended to longer, it would probably have eplit the pillow
Kflr, there being no other possible outlet fur the expansion.
Bb have cited thia case as one showing the importance of clow
ftreillEiDce of the detail in question, for not only is valuable
oe lost, but the machines themselves are greatly injured, some-
bes involving costly repairs. In turning up shafts and hear-
nt we have observed a reprehensible practice in some shops,
B that is the use of the file, Ifo good turner would employ
■pi a 'tnol to finish work that ought to be done by the cutter.
Kb tendency of filing is to produce irregularity, and when the
■rk is heavy and the speed slow, the use of the lile is the height
■absurdity, and ought not to be permitted by any foreman.
■"The beautiful glaze produced by a sharp turning tool is as
Btrly akin to the working surface made on shafts by long
bning aa any new journal can be, and consequently a well
bned bearing is much less likely to heat and cau^ trouble than
Bled one. When new shafts heat at the outset, a little time
UA patience will, in general, suffice to bring them down to their
Brk ; and in all cases it has been found the best practice in
Ih esmat^ to bo» the brsasea from a Bixteenth to as eighth of

!8 ENGINEEUING FACTS. [Div. I

1 inch larger, according to tlie diameter of the shaft, S
the journals may bottom faii'ly, anil not touch the sides at a
When shafts are 'aide bound' they wiU invariably heat, b
'q addition to the peouhar TOliing friution of the worl^ there if
added the weight of the metal, which, in ahafts of fifteen and
twenty tons, is an important item. Of conrae weigbt is pteseni
' L any case, but in a well-htted bearing it ia dead, and i
wedging weight, so to speak, such as exists in brasses whieli S
tightly to the sides of shafts. In our best machine shops £lag

e virtually disqarded in fitting large brasses to bearings ; as, i]
addition to their awkwardness, theie is the expense of them t
he considered ; besides this the peculiar liarsh surface they It
is not favourable to a cool bearing. The scraper is substituted
with good results, both of time and execution, as when wdl
le the scraped brass is perfectly mirror-like, and is reduced U
a working surface in a short time. Shafts may he well turned'
and properly fitted to their jilacea, and yet heat beyond all c
trol. This evil can aometiines he remedied by applying 'medi'
cine' to the shaft with the oil, in the shape of blacklead, sul-
phur, and, in cases of great emergency, common quicksilver ;
this last substance is most excellent for curing journals that hava
been cut of the peculiar rough aurfiice they acquire, as it pro-
duces a kind of greasy gloss that fur a sliort time covers
neglect or misfortune of the engineer. Where all other h
fail, the bras& itself must be taken out and its composition,
changed — either it is too hard or too soft for the journal
have known of a chronic hot bearing being cured in this way,
after a great deal of time and labour had been expended i
keeping it in running order, even to the extent of playing npoib
it with an inch hose throughout the trip. In the navy all the
journal boxes on the new guiihoata are hollow, and fitted with
pipes through which a stream of water passes continually,
merchant ships are also thus fitted.

'' It is a curious fact in connection with bearingii that thoy
will oceasionally defy all the efibrts of experience and sciei
reduce them to obedience after they once heat thoroughly,
possible that this eflect may be traced to a want of proportion
between the size and the labour on the shaft ; but of two bear-
inge both precisely similar ^in fact on the same shafts ire Ltkva

bEno.J .TOUENALS of marine engine shafts. 189

round ihat the one wliicli had the most duty to perfiirra behaved
tiie best. This is, of couise, an unusual case, and ia merely cited
as an example of the previous remarka. Wlien shafts set in
brass boxes heat, tliej merely cut the shaft or the bos ; bat when
Babbitt metal ia used, heating causes mischief that can only bo
repaired by ovorliaaling. One peculiar effect of white metal ie
to reduce iron journals much more rapidly than brass ; wliero
brass boxes are lined with Eabbitt metal, aa ia often the case,
tie iron journal will be found very much worn down where the
white metal comes in contact with it, while the bi'oss shell of
(he box is but slightly thinner than it waa originally. This is
owing to the peculiar toughness of the white metal. Where
jintmals are run in this substance, and well lubrioat«d, they ac-
quire a perfect surface in a short time that very much lessens
the friction of an engine or other machine. We have seen large
I'ligines 'turned over the centre,' when the steam gauge did not
■Uow a pound of steam. This is nut wholly owing, aa many
.suppose, to extreme delicacy of wortmanahip and tightness of the
working parts, hut to the yaeniim produced in the cylinder by
the almost infinitesimal portion of vapour admitted tn it ; and
although the steam gauge may not indicate auy tension wliat-
ever, there is a certain amount in the boiler which is transmitted
to the cylinder, or else the machinery could not be moved This
u a little digression from the subject of bearing)*, but is in a
measure connected with it ; for while we stated, a few lines back,
that free movement waa not entirely dependent on easy bearings,
we must admit that a stiffly coniftcted engine will not turn the
centres readily ; where the resistance amounts to more than the
vacuum ia able to overcome, of course the engine must stand still.
"A great many engineers seem to think that slacking off a
hot bearing will cool it, independently of other considerations.
This is not always the case. Too much friction is, of course, a
aource of derangement, hut excessive freeiiom ia also a fruitful
I'auae of hot bearings. This may be accounted for by the theory
tiiat the oil ia pounded out by the journal in jumping up and
ilown, and it thus cornea in contact with the naked metal ; the
fact remains true, whatever be the reason assigned. Good luhri-
canta, care, and cleanliness, will generally result in handsome
beutngaj no one will question that a large amount of power ie

•mn

ENQINEERIIfG FACTS.

Piv, UH

I

iiDsorbed by a rough bdiU'itig, or one lialf oiled. Stop up t
nil holes, and if the cciUara have much play buck forth, arrangi
leather shicldB to cuver the space ; keep dirt out and oil ia,
much better results will be obtained than where carelessness ij
practised and filth allowed to aecuinuliite."

In addition to this we may only state uur own experience, tha
if a brass is proptrly fitted, firat with the fi.le and then wi
scraper, until the sliaft bottoms ]jroper!y, that is, having a
iitg surface at the bnttcm of ab^iUt one-third the total ciro
enee, and being cleared away at the sides perfectly free, n
need be entertained of such a journal heatiug aa long as it n
the proper attention in oiling, keeping clean, &c In locomoUn
practice this ia particularly well attended to in fitting all a
box, connecting aud coupling rod, and other brasses, and the n
suit is that they are rarely known to heat; and it is well knov
that for both speed and hard work the locomotive has not itn n
equal in any class of machinery.

A new antifrictional bearing material has been patented bf J
Mr. If. J. Aimea of Maudieater, whigh is said to heat (
ordinary pressures, aud with a minimum wear ; its compa
is described as follows : — " Animal fibre, plumbago, steatite
caoutchouc, or gutta percha, and any resinous gu
glue or size, are combined in proportions almost immaterial i
the animal fibre be in sufiicient excess ; the composition being
moulded or out into the regular form.

" Vegetable fibres have been similarly used befo
much as animal fibres, such m silk, wool, hair, or disintegratec
skin or pelt, are much more durable, and possess other euperioi
qualities, the patentee employs it in combination with Ibe afoF»
aoid materials in contradistinction to vegetable fibres, as not hav-
ing been hitherto bo employed. In bearings, journals, (
frictional surfaces where water may be employed to assist in
lubrication, he prefers to employ a resin or gum called ' rhiM
copallinus' (gum copal), or a varnish made therefrom,
medium to unite or bind tc^etlier the other components, a
gam will best resist water in a heated state. The
, bushes, journals, steps, and other frictional surfaces e
f oast or otherwise produced with cavities, spaces, or excavatlom
r tbfi reception of the composition or filling, which i

IKK Kvo.] STEAM ENGINE CONSTBOCTION,

lexl to and in immediate contact witli the shaft or wearing i
i.e; or, if required, the composition may, in some instances, be
■■■d aoliti, without the support or combination of metal or wood.
i i.i: composition will be found suitable for such pnrpoees com-
i^i.'d of silk, wool, liair, or other animal fibre (either in a fibnnis
■uU: or redaced to a pulp), two parts; plumbago, steatite, nr
.fuilar lubricating or an ti friction al material, half a part; and
. -iiioud substance, gam, or Tarnish, half a part; or in such other
I'lportions sa ciTcn[u3tanc<^ may require."
In concluding the subject of the steam engine we shall notice
I' most modem features in the construction of such engines, as
.i,ri that of their details, TIte great hulk of steam engine work
> [jhw performed by the aid of machinery, very little fitting re-
1 iriiig to be done by hand in firat-claas establisliments. Cylin-
r faces, valvas, and links, as also innnmerable details, are fin-
ned by the planing machine, self-acting lathe, and slottiui;
i.ii:hLne. A very beautiful specimen of machine work was ex-
j:l<ited in the International Exhibition in the shape of a slot
link fur a marine engine, turned oat by Mauilaley, the atot, U'
ilie greatest nicety, splitting the centre punch marks determining
the radius. Such a finished Unk, we should say without heaita-
'ioii, was quite fit for regular working; indeed, we tliick that
irora sneh mnebine work the different parts would much sooner
<;ijiiie to a good and true bearing than where the file was used,
fur, in the first place, only a few skilled workmen know how to
liulil their file so as to produce tme work, and, in the second
(jlace, the very beat filed work ia far inftrinr to machine work.
A good and exceedingly handy machine is the traversing drilling
'^:ichtne, wliich makes a most superb job of cotter holes and
liV other work re i^uiring oblong slots. These are at all times
■ \]iensivB to cut by hand, and when done the worknian has
J ;i>at difficulty in finishing such perfectly parallel The apaci-
;i:n3 turned out by the macliines exhibiteil at the International
[^■i.liibition presented a surface perfectly parallel, and shining
!ii.' a mirror. The following practical article on the details of
.-iLuum- Engine Construction appeared iu the ' Enijinenr :' —

" Nothing can be said against the working of a well-constructeil
Ijeam engine, although it is both heavy and costly at the ontaet.
Dm jipx«l yMteiu of this class of engine, non-ui.M:vienBVii%, B.ad

ENGINEEKING FACTS.

[piv. urn

^H 'with a single 22 incli ujlinder, and 1 ft. 6 in. stroke, has 5 tontf
^H 2 cwt. ill the coIuniDa, 3 tons 6 cwt. in the entahlaturo, and S
^H tnna 9 cwt. in the beam, or 10 tons 12 cwt. in the parts
^H tioned, whereas all the other parts, exclusive of fly wheel (but
^H including a sole plate of 7 tous 14 uwt.), weigh but 30 tons 1^
^H cwt, the whole weight of the engine being 30 tons 19 cwt, <
^^ elusive of a fly wlieel of 13 toua 10 cwt. The weight due ti
^1 the beam, or say, in all, 1 1 tons, would be saved if the horiaonta
^H arrangement wore a<lopted, and the "latter would require a i
^H le^ number of parts aud wearing surfaces. It ia difficult t
^r discover exactly the grounds of objection so often made to t

horizontal engine, although one commonly hears it said that Uij
weight of the piston wears the bottom of the cylinder. Tla
bottom of the cylinder may be slightly worn by the weight a
the piston, but the principal wear of horizontal cylinders, wheth«
in marine, locomotive or iixed engines, ia invariably upon th« '
upper side. Not only will an examination of a worn horizontal
cylinder always disclose this fact, but the reasons for it i
aiifficiently apparent on a little reflection. All luhrieatiiig tdbt
terial admitted to the cyhnder gravitates to the bottom, leaTing
the upper surfaces comparatively, dry, and furthermore, whenever
the piston is so loose aa to ' blow steam,' this leakage will ta,"
, place chiefly around the upper half of the circumference of t
Steam, in ' blowing ' past a leaky piston, will rapid^
' both the cylinder and the packing. As for lubricatioD,
we should never admit a drop of any lubricating material to •
steam cylinder having gnn metal packing rings, excepting only
when the cyhnder was steam jacketted with high-pressure eteam,
or when superheated steam was used The packing of a wall
titling piston ovight never to be pressed outward with a ft

r than 3 lb. or 4 lb. per square inch, and for this, and eveq
a greater stiflness in the packing, the slight condensation o
steam always going on within a cylinder, however protected, ia
sufficient for evei'y purpose of lubrication. Wo know of largs
cylinders, both in marine and in land engines, which have b
in use for years without other lubrication than that afforded i
tlie steam, aud they have maintained an excellent internal enr^
face. We dwell upon this fact ia connection with horizontal
8 far this reason : if the cylindei be once regularly Itibi

eEsu.] working of ENGINES-

W

^^Hfed, i&y with ttiUoiv, it will be found that lubricating material

^^^b be thei«afbei required, and that cutting is likelj to follon' if

^^^B tallo'w be dLicoiilijjued. The cylinder shouM be ruu with-

^fw tall<tw from the first. Li Iwrizniital en^nes, therefori-, lu

whidi tuUow is regolarly used, the upper internal surface of the

I'vlintler £tila to retmn it^ share, and cuts in consequence, altliou};li,

.ii! a rule, if no tallow were used at all, there would be no cutting.

We are not stating a theory, but an indisputable deduction from

the ascertained &at that marine and fixed steam engine cylinders

»:ldom require other lubrication than is afibrded by the steam.

" Locomotive cylinders, of coiirse, must have lubrication, as
the engines ore often run for considerable distances (as down iti-
clines and near termini), without steam. So, too, if the valvo
gear of a locomotive be reveraed, aa is sometimes done while the
uigine is still running forward, and without admitting steam,
t air and soot is jjumped fi^m the smoke-box, through the
laust porta into the cjlhiJers. But horizontal cjlindctH, oven
r the severity of locomotive service, do not require to be
&'boi«d as often as might be expected. And when reboring is
necessai'y a horizontal cylinder may be bored in dlii by means of
a portable and easily applied apparatus, now very commonly em-
ployed on railways. The vertical cylinders of beam engines can-
not be aa conveniently bored in this way.

" At high s]>eeils the momentum of a heavy beam would be
very great Tliink of a beam weiglung several tons with its op-
iate ends working up and down at the rate of from 600ft. to
toOft. per minute! A great and useless strain would be thus
)ught upon the crank pin and upon the main journals at the

I of every atiMka The Cornish engincci's regard the great

b<Ams of their engines as counter weights, and however massive
they may be, their momentum assists in forcing out the contents
of the pump when, after the steam in the cylinder haa begun to
••xpand, its pressure has fallen below the mean load on the pump.
Indeed, when it was first proposed to employ wrought iron engine
beams, and thus, while gaining in strength, to save in weight,
•ome of the Cornish engineers objected, because weight in the
a was the very thing they wanted, although one ton of iron
^n the pump pole has more effect than two or three tons in the
In the Cornish engine, weight, in vibrating c

191 ENGINEEBING FACTS. piv, HI.

eating motion, is exactly what is required, bat la a, rotative eti-
giae it is tlie very tiling to be ayoided. The u'rangement of the
beam engine is better adapted to the employment of the parallel
mution, but, as made witli radius bars, no parallel motion
guide the piston rod in a truly straight line. There must be
Bome, although not mucli, deviation on every stroke. But the
glide Ixirs and guide blocks of the horizontal engine, while
Huring absolute atraightnees of motion, need not cause much more
frictioa than the heat parallel motion. The plan of the horin
engine is iavourahle for the employment of a long connecting
rod, say of at least three times the length of the stroke. In this
case the maximum vertical pressure on the guide bars will bo
one-sixth of the preasure uu the piston, and as the mean vertical
pressure throughout the sti-oke will (BUpposing the engine not to
work expansively) he nearly 70 per cent, of this, the mean
tical pressure for the whole stroke will bo about llj per cent.
of that on Uie piston. As the co-efficient for a well lubricated
cross-head ought nut to eswed one-eleventh of the pressui"©,
have as the loss by the fiiutiun of the guides about one hotse-
powei of every hundred. Tliis is not much, certainly. Speaking
of gciides, we should give a much more liberal allowance of bear-
ing surface than is provided by most engine makers. The guides
wear all the better if the maximum vertical pressure upon thein
does not exceed 25 lb. per square inch, and for a ISin, cyliudv,
working 60 lb. steam and having a good long connecting rod, wa
should not make the cross<head bearings less than 90 aqnan
inches in extent, or say two blocks, one on each side of tti^
l>iston rod, and each 3in. wide on the bearing and ISin. loi^.
We would always make east iron cross-heads, with the pin eithei
cast in, or fitted in, in wrought iron. As long as one end of the
piston Tod is keyed within a cast iron piston, the boss of which
is seldom over-strong, it appears needless to forge a costly ' afaape ~
to receive the other end.

"All land engines lahould, and, we heheve, sometime will, be
regulated by the action of the governor upon a variable expan-
sion gear, so as to dispense with throttle valves and wire drawing
the steam. Mr. Petrie of Rochdale, Mr. Brownlee of Glasgow,
and others, have applied arrangements for this purpose. The
Fivnch makers, as MM Farcot, and others, have adopted this

^aon Em] WOEKING OK ENG15ES.

tetii, but it is [wrhapa best carrieil oat iu & cla^ of eii);in«a ot

hicli two, of Prussian make, were exLibited in the late Eslii-

I, aud which were exact copies of the engine kuowu in the

^iteii Statea aa Corlisu' eugiue. One made by the (.'orliss

tie Company, of Providejiee, Khode Island, United

«• working at Meaara. A, Pirie and Co.'s paper mill

t Aberdeen. These engines are reguhitt-d twice during ew;h r

eluUon, taking, according to the requirements of the woi'k, frwm

e-twentieth of a cylinder-fuU to an entire cylinder-full i>f Bt^ain

I each stroke. Engines of the same construction, emi.iloyeil ii

lolling milla, work under a load varying IVoni 60 to 3ij0-hor«:

power within 5 seconds, and yet without any sensihle alteration

in their speed. Mr. Corliss employs valves and valve gear iJ'

peculiar construction, and connected in a jicculiar manner with

the regulator. We have nu doubt that Pitcher's hydi'aulic

govemor, as mode by Messrs. Fanner, of Sulfurd, miglit be nse-

fuliy applied to shilt a link motion, and thus to ucc<jmplislj iu

part the purpose of Corliss' valve gear.

" We believe it to be time, with increasing pressures and

1, to make longer bearings on engine shafts. The Buultoii

1 Watt pnmping engines at Stoke l^ewington furnish a notable

e of niisproportion in thia respect. With 6ft. cylinders

3 8ft, etroke, and with a 25tL fly wheel weighing 60 tons (the

D ftlone, 24in. by 17in. nearly, weighing upwards of SO tons),

i journals are but abi:iut ISin. in diameter and 30in. lojig.

e engines, as is well known, have been almost reconstructcxi

nt the pump end, but although new plummer blocks have been

put in, with 4|i]i. holding down bolts going 36ft. deep into the

foundations, the fault of too small journals baji not been corrected.

Wo lately saw a pair of 18iiL cylinder engines working fiO lb.

steam, anil having 6^in. Jonmals apparently but 8ut. long.

On the other hand, we may observe tliat one of the best working

pairs of botizontal engines we have evi:r seen, and having 12iii

cylinders, S^l't. stroke and working 60 lb. steam, had 6Jiu

journals IS^in, long, the abaft being of cast iron.

" Piston valves may yet be found to answer best for eteam
engines. Messrs. Simpson and Co. have already used them very
successfully for large pumping engines, the 14-in. pistons fonuing
the valve having a sitigle gun metal ring Gin, wide on tlie face.

I

198 EXGINEEEIKG FACTS. [Div. Ill

and feebly pressed uut by a small siiriiig. Tliera is a. difficullj-
■with self-adjusting packing on jiiston valves. The rings are likely
to spring out on passing the exhaust ports, jaat ae Bamabottoin't
wire packing springs out at the eniia of the cylinder where coun-
terbored, and in passing the induction ports the liugs of piston
valves will, if fitting elastically, be pressed in by the steam.
There is an adjustable, but not self-adjusting, packing ior piston
Talves, of which we have heai'd good accounts. Each jiiaton of
the valve hiis a broad cast iron ring, projectin<r over the edge of
the junk ring as well as over the edge of the piate cast
central boss. The ceutml boss ia turned so largo that the ring
ret^uirea to be sprung on, and its tendency when on is not to
expand, but to coatraet closely around the turned boss, wliich
serves as the body of the piston. The ring is cut open at one
point, and to oounteraat its oontraction a wedge-shaped key is
forced by a screw between the ends where the ring is cuj open.
By means of this key, wliicli fills out the full ciron inference of
the piston, making it perfectly steam tight, the ring can be set
out to any degree of tightness, while at the same time no prea-
aure of steam can press the ring inward on passing a port Al-
though these valvea are not self-compensating they work steam-
tight for a very long time before the key requires to be tightened
to set out the packing ring. We have seen them working rapidly
With the end covers of tlie piston valve chajnber removed, and
there was no perceptible leakage of steam. The least poasiWo
power is required to work well made piston valves, whereas, with
short stroke engines especially, a great amount of power is ab-
sorbed in working largo slide valves. It is questionable whether
piston valves really require packing, or rather whether it is not
'iheaper to turn thenj out of the solid, and to replace them when,
after a considerable time, they begin to leak much steam. We
are now speaking only of small engines. Mr. David Joy, of
Middlesboro'f has employed \inpackad or sohd cylindrical steam
moved valves fur a considerable time. He has made them up to
5^in. in diameter, and worked them at 300 strokes per minat^
under 50 lb. pnissure. When made with long bearing suriaces,
the valve and bored chamber in which it works being of the aune
metal, say oast iron, they wear a vnry long time without leaking
flu/ notahle amount of steam,"

^HEari^ce Eng.

P1ST0K3 OF STEAM EXCISES.

The writer now proceeds to the consideration of pi«toiuji
fore, bowever, concluding his article, we would hens interpolalti
s very excellent and procticul paper read before the Imtitutioii
^^M Mechanical Engineers, hj Mr. Geoi^e M. Miller, of Dublin,
^^u. the Buliject of metallic packing for steam engines and jiumpe.
^^m " This packing consists of two ring^ pressed outwards agaiust
^^Be cylinder by the preastire of the ste^ as it acts on the alter-
^Bate faces of the piston, without the use of any springs. This
constraction of piston is used by the writer in the lucomotive
engines on the Great Southern and Western Eaiiway of Ireland.
Tie piston is of cast iron, 2 in, in thickness and 16 in. diameter.
Vo square gi'ooves are turned in the edge of tlie piston, § in.
Jt width and f in. apart, and a corfesponding steel ring is fitted
Kto each groove, the rings being divided at one port with a plain
untt joint, and sprung over the piston into tlieir places. Two
small lioles, ^ in. in diameter, open from each face of the piston
to the bottom of the neajeat groove, whereby the steam is ad-
mitted behind the packing ting and presses it out against the
eylinder bo long as the steam is acting upon thnt face of the
piston. The alternate action of the two rings is continued as
long as the steam is acting on the piston, one of them being
always pressed steam-tight against the cylinder.

" Another form of the pist<in has been used in eases where
the piston is desired to be flush on buth faces or to lit a cylinder
with flat covers ; in this a circular flat head fotged upon the pis-
ton-rod is fitted between the tnmed faces of the two halves of a
cast-iion piston, which are held together by turned pins riveted
over, forming a hollow piston flush on both faces, fast upon the
H'piBton-rod, and without any loose part besides the two packing

Hk " The ends of the rings, where divided, are made either witli
^^ butt joint or a lapped joint. The piston body is turned to
pass through the cyhnder easily ; and the joints of the rings
have been found to be practically steam-tight. In some cases
the joints have been tonguod, as shown,- but in the writer's ex-
perience this has not been found requisite; the butt joint has
invariably worked well, whilst it has the advantage of perfect
simplicity of construction. In pistons whore the packing ring
traveb otbt the apeaiiig of the cj'lindei part,a.sicnii.fe\*s^\'i.^a^J

p

EtiGIS"EEHISC FACTS. [DlV. ir

I

in the bottfim of tlic groove, entering a. sliort slot in the packing;
'ing, to prevent the ends of the ring coming opposite the cylinder
F jiort, but still leaving the ring free to travel roncd a little in the
piston grooves; but it ia preferred for the packing rings not in
travel over the cylinder ports.
I " These steam-packed pistons have heen used more than seven
years in the locomotivps of the Great Southern and WeBtern
RaUway, and have proved so satisfactory and advantageous that,
their use has been extended to all the 94 locomotives working
upon thftt lina The following are the results of the working in
the engines running from Dublin, as regards the diu^bility of
one set of rings, the period of their wear, and the mileage of the
engines whilst wearing them out, Nineteen engines workiug
with one set of steel rings averaged 33,020 miles and 16^
months' running, one engine having worked for 3 years and run
S3 much as 98,073 miles with one set of packing rings. ■ Five
engines working with one set of brass rings under the sam
cumstances avernged 30,986 miles and 19 months' running
greatBst work amongst them being 2^ years and 43,13r miles,
Twenty other engines with steel rings, which are still in
have also averaged 40,444 miles and 21 months' work, o:
these having wfirked for 3^ years and run 94,399 miles with the
^ original set of rings.

"The general result of the above is that one set of steel pack-
ing rings have lasted 37,000 miles and 19 months' work, and
one set of brass rings 31,000 miles and 19 months' work, the
liifference in durability being about 16 percent, in favour of
tlie steel ring*. In some of the individual cases of the pistons
with steel rings, a very considerable variation from the average
result of 37,000 miles is found in the durability of the packing
rings, some of them having lasted 2| times the average, and

only as ranch below the average. In the cases of the b
■inga the variation is not so great^ amounting to IJ times the
iverage in the highcit, and about aa much below the average ii
[■the lowest. Thie variation in wear has not been fuily acconnted
it may have occurred from a different charaeter of metal in
'the cylinders, from priming of the boiler, and from the presence
iiifgrit in the water; but the writer has reason to believe that
rings hrtva Iwcn frequenUj' 'j^n.V »v\jq tiotV. eudset nith.*

_4ifB

Id

E Eng,] P13T0N3 OF STEAM ESGINFS, IPC

re upon tlie cylinder from Iheir own elasticity, thus cnasing

iioe of wear. It is tbund the best plan to tnm the rings to

exact diameter of the cylinder, and to put them in irithout

Bpriug upon them, so that they are not subjected to any

except when the steam is acting on them. The 8tc«I ritig4

now slightly tempered, to admit of their being sprung into

gciioyea without altering theit form. In all these piatuns

steel packing rings were | in. tliick originally, and | in,

Lde, and they were worn down to about | in. thick in the Ihin-

part before being removed. The brass rings are worn dowu

7-16tha in. until tlicy are j in. thick. Specimens were

exhibited of steel rings from four engines that have worked

38.000, 61,000, 84,000, and 96,000 miles respectively, since

lirst put into the pistons. It must be remarked, that, when

opportunities occur, as when engines are under repair, the rings

are taken out and reset to the size of the cylinder.

" It ie fuund in praotice that two steam purirs of J in. dia-
meter are quite eufficient for each of the steel packing rings.
The tinga niugt be made to fit easily in their groores, so as lo
move freely, with a, clearance of l-16ths in. at the bottom of
the grooves for the steam to pass round beljiud the rings. No
difficulty has been experienced from the steam passages becoming
ipped up by a moderate nse of tallow in the cylinders.
"The use of this piston-packing in locomotive engines has
m. productive of economy by reducing the friction, and by
prolonging the wear of both pistons and cylinders. It will be
obeerved that only one ring is in action at the same time, and
that when the steam is s)mt o^ as in descending inclines and
approaching, stations, the piston is fi'ee to move without any
Action. The cylinders of the four engines from which the
specimen rings exhibited have been taken, show a highly
polished suri'oce, are very little worn, ami are nearly parallel
throughout. The operation of putting in these rings so as simply
lu fit the cylinder is extremely easy, whilst great care and skill
are required in giving springs the requisite degree of elasticity,
and in making them with maintain it.

"A set of brass packing rings was also exhibited, taken out
of the pistons of a pair of vertical stationary engine cjlindera at
the Dublin Eailway station, in which they have been in constant

I

ft

I

Sno ENGISEEEING FACTS. [Iliv. Ill,

work for the last four years, witli a pressure of 60 lb, ateaiu.
The diameter of the cylinders is 19^ iu., and the rings were ori-
ginally j in. thick anil f in. wide ; they are now worn down to
fi-16thin. thick.

"A number of stationary engine pistons are working with
these packing rings, and they hiive proved very durable and
thoroughly satisfactory, giving an advantage in reduction of fric-
tion, and in preserving the cylinder face in perfect condition.
In one case of the engine of the Oldbawn Paper Mill, near
Dublin, with vertical cylinder 16 in. diameter and 21 ft. stroke,
working with &0 lb. steam, the cylinder had previously been
worn considerably out of truth and much grooved, and one of
these pistons was put in having two steel rings of } in. width
and I in. thickness, and was in constant work for four years
\vithout the packing rings requiring renewaL They have lately
been taken out for examination, and were found to be stiil ^ in.
thick ; and the cylinder, from its previous defective condition,
has been brought completely to truth throughout, with a highly
polished eurfuce.

" These packing rings have also been used for four years for
pump buckets, and have proved very satisfactory. In one case
of a double-acting pump 8 in, diameter, the two packing rings
are of brass, | in. wide and 5-16ths in. thick, and are pressed
out by the pressure of the water acting at the aUornate faces of
the bucket through t*o porta, ^ inch diameter, similar to those
in the steam pistons, Tliis pump had two years' constant work
at quarries and bridge foundations upon the Great Southern and
"Western Railway, before the packing rings required renewal.

" In the case of single-acting pumps the bucket has only a
single packing ring with porta opening from the upper side. A
pump bucket 5 in. diameter bas'been working constantly fur
2i years at a station on the railway near Dublin. This bucket
was exhibited, having been taken out for the purpose ; the pack-
ing ring was originally J in, wide and ^ in. thick, and has worn
less the l-16th inch in the 3^ years that it has been working
up to the present time. As the diameter in tins case is too
email to allow of the ring betfag sprung over the body of the
bucket into its plac«, it is put in by means of a jnnk ring screwed

at the under side of the buoki-t

PISTONS OF STEAM ENGINES. 301

"An application of the Boino constractiuti of packing tbat h»s
lieeu made to the gland packiug of a 9 in. pump plungeT, in
' b two hrasa packing rings ore used, i in. tvide and g in,
;, just like the piston packing rings, except that they act
e opposite direction, being pressed inwards upon the pUnigrr
3 pressure of the water through the portfl.
PMr. Miller exhibited specimens of the steel packing rin^s
[I the pistons of four locomotives which had run fn>m 38,00(1
56,000 miles; and also the hra» packing rings fnm the
s of the stationary engine, together with the bucket of the
I. single-acting pump referred to in the paper.
PDnring the discussion which followed, Mr. J. Fernie said he
pglad tJiat the subject of packing rings for pistons, which
B such an important part of a steani'engine, had been brought
rard in the paper jost read. He observed that steul pack'
■ rings had not been found to wear well in other instances in
[kih they had been tried, and moreover they cut the cylinders ;
i Lb inquired whether the cjliudeis in which the ateel rings
%id been working for so long a time were made of a very hanl
quality of metal

" Mr. Miller replied that the cylinders were cast aa hard hs
they could be made, consistently with allowing of the subsequent
boring. The packing rings were made of common shear steel,
and sometimes wore down irregularly in thickness, but in many
cases the wear was regular.

m " Mr. J. Femie asked how the steel ring^ were made.
^k'^ Mr. Miller said the steel was rolled in lengths of the required
^■Kpe, bat ehghtly tapering in section from the outer to the inner
WmOB, so that when bent into a circle the two edges of the iijig
became nearly parallel, giving the same depth of ring throughout
its whole thickness. The bar was then bent in a miaiiature plate-
beilding machine, hammered to the size of the cylbider, and
fitted into the groove in the piston by simply filing, without
any other work being spent upon it. At first the rings were
turned in a lathe out of a steel cylinder and then cut across,
but it was found better to get steel rolled of the proper section
~* t the purpose, and afterwards bend it and fit it by filing.

" Mr. F. J. Bramwell inquired what amount of sjiring wiis
n to the packing rmga before they were pnt in tlieir place.

I

I

202 ESCLNEZIUNG FACTS. pii

and wlmtliet the piston hail nver been tried without admittii
the eteiini behind the riug;^, iu order to see how far it would I
rend«red ateara-tight by the pressure of the rings alone withoi
the Bteatn l)ebiiid tbem.

"Mr. Miller explained that the packing rings were put i
without any amount of spring of their own, being made no larg
than the diametei of the cylinder, in order that there mifjht
no pressure against the cylinder, and therefore no wear wbUi
rtiuning with the steam shut off.

" Mr. J. Femie remarked that the steel packing rings ii
Ramsbottom's piston, generally three in number, were aet with
certain amount of spiing in themselves, by which the reqm
pressure against the cylinder wa^ obtained. ; and that plan p
qniral the cjlindera to be of rather hard metal to stand t
constant pressure iu working. He inquired whether the bm
packing rings that had been used had been adopted for tha p
pose of working in soft oylindera,

"Mr. Miller said the rings iiri^t used with this mode of pa
ing were brass, and after some time a set of steel rings was tB
the experiment being proceeded with rather cautiously &om fi
that the steel rings might cut the cylinder; but it ^
they did not do so, if fitted in without any spring whatever il
the rings themselves, but with only the steam behind f
them against the cylinder. The result was that it veiy n
occuTfed now that a cylinder raq^uired reboring : the cylindet
not only preserved a fi.ne smooth surface, but kupt more pojulle
than under the old modes of packing the pistona The reaso
of using the atecl rings and discarding the hriiss was that tfa
steel lasted about twice as long.

" Mr. J. Femie asked what was the weight of the steam-packe
pbton for a loeoniotive cylinder of 15 ia diameter.

" Mr. Miller replied that the weight of a piston of tbatUi^
meter was 64J lb. without the rod, whicli was 2| in,
the piston was 2 in. thick.

" Mr. J. Femie said they had tried some pistons on the Midlam
Riiilway on this principle of packing by the jiressure of s
behind the rings ; they were wrought iron pistons forged BoUj
on the piston rods, and the packing rings were of brass ^ inch
aqiians ia SBCtion. A very Voug nuieasp was got out of t

«cEso,] P13T0SS OF STEAM EN'r.lSES.

I, 1)ut it was fonnd thnt with soliil piatfim thcro was n g
of troTiblo from tlia nwx'asJty of getting the criiit^haatls off
row tlie piston out, wlinnever il wns wanted In ilo anytliinj;
IB piston iir look at the packing rings ; anil they had tlii^n?-
now gone back to the old-fashioned piston with a JQuk rin^
I tiie face for gt'tting at tho packing raigs. The benr-
euHace waa now reiluced to 1 ia in tho pistons ; there wi-re
^ in. pocking ringf, and theee gave a longer mileage than
1 to be got out of two 1^ in. rings. A grent width of bear-
sorface was not reqnired, but a sninll bearing surface was
«ratile, provided the rings were made to fit tlie cylinder ac-
'y all round ; anil Mr. Enmsbijttom certainly had the oreilit
Aving first calleil attention to the advantage of narrow pack-
rings well fitted. The 16 ia piston now used in tlio Mid-
l locomotives weighed IJ cwt., indading the piston roil, hav-
bden rednced in weight 28 lb. below the previons m^e, in
a of wliich a longer milei^ waa gtit ont of the pack-
nngs ; the wear of the cylinders was also greatly rednced, a
lUy polialied aurfuce being maintained. Formerly there used
a great deal of tnmble from the cylinders wanting reboring,
now with the narrow packing rings and light pistons this
. quite removed. He thought highly of the Btoara-packed
I, and the reatilts obtained in the durability of the packing
■ iTCTe certainty very extraordinary, 90,000 miles far exceed-
aay mileage previously attained. In his own experience
it 20,000 miles was the durability of a set of J in. sqnan>
B rings, and then they would want setting up tmce or three
IS during that period. He enqnired how often the steel pack-
rings had been set up before they were worn out.
'Mr. Miller said the packing rings had not been examineil
eet up at stated times, but whenever the engine happened to
ri for casual repairs the piston was taken out, and the rings
aiined anil set out if required, by slightly hammering them
Tound to bring them agiiin up to the exact diametiir of tho
nder j or they were replaced by new rings if worn out. The
ilta of milpago with the different sets of rings were drawn from
itum of the exact mileage of all the engines that were work-
under his own observation.

E. F, J. BmmweU thought tliete would uIway" ^ iinrl^

I

ENGINEERING FACTS. [Div.

the Ihll pressure of the steam behind the rings that there wa.
the cylinder, judging from the quickness vith which the ati
filled the cylinder of an indicator through a small orifice.

" Mr. Miller said that with the brass packing rings first ti
the holes behind the rings were drilled \ ia diameter, but ti
was found too large, and they were therefore reduced to ;
a Uiameter, which proved to he sufficient for ohtaining t"
required pressure to make the piston steam-tight in the eylinda

" Mr. C. F. Beyer, the Chairman, inquired whether the pistoi
body was turned much smaller than the cylinder or only k

" Mr, Miller replied that the piston body was turned down ti
about 1*32 in. smaller diameter than the.cylinder, so as .to paa
easily through it.

" Mr, F. J. Biumwell asked whether the packing rings fiUa
out to the size of the cylinder as they become worn, or whethfl
when the steam was off they returned to their original insiti^
diameter.

" Mr. Miller I'cplied tbat when takeii oat after a great deal o
wear the packing rings were slightly smaller in diameter than tl
cylinder, and then requii'ed setting out by hammering. Sometime
they wore perfectly cnually all round, and sometimes more at tl
ends or in the middle.

" After some further discussion, the Cliairmnn remarked tbM
after making and employing a great many descriptions of pietonsi
he thought the steam packed piston described in the paper vi
a very good one, and it had the gii'at advantage of being v
simple in construction. Formerly, it was a great object to kee]
the steam out of the piston, on account of the internal packin
springs; but in this piston the steam was admitted inside to a
as the spring upon the packing. The practical feature of tin
new pistons was their great simplicity of construction ; but to Ml
Eamabottom was certainly due the credit of first simplifying thi
construction of pistons to so great an extent He considered th(
piston now described ought undoubtedly to work well, b
tiioro was so little about it to get out of order, and it could n
do otherwise than prove highly satisfactory. He proposed I
vote of thanks to Mr. Miller for his paper, which was passed.*
Ill coniirmatioa of the forogoing ^x^^^*^^ ua,i^r, we maf a

i:x{ierience of Ur. Kdinabottom's pu:king uf luinl d
'Inw moor rings, simjily sprung iu to the cylinder, is, that it u
liie most simple and most ecouc)miMtt packing in existence, — exyi^-
rieiicB wbioii is fully borne out by the London and ^orth-^i^lcin
Kailway Com^iany, aud other lines using it; we bboulJ My, liow-
cv\!T, thUit the admission of steam beliind the rings is a decidml
iuiproveniput, imd likely to equalize the spring at the proper tiniu,
itnd thus malce the rings run till they vore completely worn
tlu-ougb, Katnabottom'a packing having fK'quently to be taken
■ int and replaced with new rings before the old ones are quitu
worn out, owing to their having lost their spring. Continuing
again in BonoUiaion the ' Engineei'g' article: —

" 'tis. Richard Boberta made solid locomotive pistona, 1 lin. in
diamet^, in 1834, and they answered well fur a considerable
time on the Liverpool and Manchester aud Dublin and Kings-
town Railways. A late attempt, however, to employ solid loco-
motive pistons on the North Loudon Eailway completely foiled.
Mr. Humphrys, of Deptfuiil, has for many years made donkey
tiigiiiea with solid cast iron pistona, and ouo of these which we
have lately seen, although but 3iiL wide for a diameter uf 10 jiu.,
and although it had done a great deal uf work, was in excellent
coudition, and not perceptibly smaller than the internal diameter
of the cylinder. "W"e should not, however, like to depend upon
them unless their breailtb, as measured on the wearing face, waa
equal to at least one-half of their diameter.

""If engineers chose to u.^e them they would find cust iron
[.■ccenldc hoops better than those of any other matoriaL They
wear aa well as gun metal where, as in the case of well propor-
lioued eccentrics, the pressure per unit of area is not great, and
iMSt iron is free &om the ' spring ' wliioh gun metal hoops have
iilieti not made exceedingly heavy.

" If, however, gun metal wearing surfaces be preferred, there
In no cheaper or better way of making them than that Oiloptud,
if not invented, by Mr. Humphrys, of Doptford, He employs a
strip of hard rolled brass, say of Na 13 gauge, and cut about lin.
shorter than the circumference of the eccentric aa well as a trifle
uari-ower than its width. This atrip is drilled with several holes,
til allow of the free passage of oil, and then lieiit around the
pcctjntric, the hoop being bored out large enough to go on over

r

I

I

208 ENQIITEERING FACTS. [Div

it This brass u fruu to turn either with the eccentric o
within the hoop, as luay hnppen, and aa il aomtstiiiiefi turns m
is sometimes at rest, it really affoRU a double weoi'ing i
It is more durable by far thuu niiy other kind of eccentric hoop.1

" The time will daubtless come when, tor most purposes, single 1
cylinder engini'S will be prefurred to ddubla cyUiiders. Duubl«
cylinders have one e.^peciul advantage ; if onu engine break dowK
another may generally be worked. On the other band, doulilo.
cylinder engines, having twice the number of parts, are always
mora likely to broak down than aingle cyhnders. Tudaed, fi
some purposes, double cylinders, or coupled engines, are, if m
almoat impracticable, at least troublesome. Cuttpled blowf
enginea are so owing to the great and rapid alteruatioits in thi
strain on the coupling shaft The intermediate shafts of s<
ships are always the moat troublesome in respect of breat
and for large double cylinder Oijcillntiiig engines the AmericaiU
have found it best on this account to place the two cyliiideni oi
ia &ant of and the other behind the shaft, the cr.Luk pins {
both being in nearly the same vertical plane and connected bj il
'drag link.' Aa for getting a single cylinder engine 'o
centres,' none but a careless enginenian would (except i
cose of a locomotive) allow it to stop on the dead centrua. Neatlj
all the large American river boats, coasting steamers, and fi
boats, have single cylinder eiiginea, and aevei'ol with lOS-
cyhndec and 12ft. stroke are now being made for o
on the Pacific. An engineer who would stop one of these engiaa
on the centre would, after one or two reprimands, be dLsmiesed
Even for large sci^ew engines, with from 70-in. to 84-in. cylindeqi
and from 3it. to 3R. Sin. stroke, the Americans more cutiimoiil|
employ single cylinders, and with much advantage

" The strong point with the advocates of coupled eugmca tiasi
however, been uniformity of motion. With a heavy fly-wheel,
however, and especially at the higher apeeda now in favour^
single engines run with a great degree of unifunnity, eaough m
believe for any purpoae, even if it ba cotton apiiming ou Sm
couuta. We will anppoae a 16-ii[. cylinder and 4fL atrolca
working with fiO lb. steam at 60 revolutiona per minute,
the fly-wheel be lift, in diameter at the centre of the section
of the rim, and let the weiglit of the rim be 20,000 IK Mor-

lljnt Ekq.] single ASD DOUBLK cylinders. 307

feaa it Ihen will, nt, 44i^ ]>*:r tiecotid, thr fly-whecl rim uuti-
e of 596,232 fuot-poiuiiis of meclianical pi>wer, aitil
biliag ofT&oiu 60 to even 5S revolutions, 17,129 foot^pouixlo
'» power must be libt-ratej, this alone being equal to a inwin
e of 21 lb. per square inch on the Ifl-iu. piatoti thmu^h-
(its stroke of 4ft, When we consiUiT that the movint; puri-^
whinery dj'ivea have, in the aggregate, a large uuOQIit
Lomeutnni, or stored up mechiHiicil (lower, we may saftly
|t Ihe heavy and rapidly moving By-wbeel to redress, almor^t
tely, the irregularities resulting from the variuliU- pressure
nittod to the crank. In the case of a flour mill with several
■ of heuvy 4ft. stones, the Upper stone making from 130 to
I reTolutiona per minute, a considerable and prolonged vari-
le power must occur in opler to sensibly alter the

e gratified by knowing that some of the iiii>f;l eminent
i, both in this euuatiy and abroad, agree with us in um
a single cylinder. We will not mention the names
I English engineers who share our views, but we may say tliat
^vlieu we lately had occasion to discuss this point with Mr.
Horatio Alien, the foremost American mechanical engineer, Le
ii.-)«ared us that if he bad to construct a marine engine of great
[tower be should unhesitatingly adopt a 15U in. cylinder in pre-
ftronce to two of 106 in. each. The success already attained
abroad with single 105 in. cylinders aiforda good ground fur tliiH
])art.iality."

r

208 EJfOlSEEHING FACTS. [Drv, IT.

iii!iay important fecta weie elicited. I'lie trials were competitive,
and a fund was aubacribed by a niunbeF of tiDbtemen and gentle-
men from which :6700 was offered in tlie shape of prizes for tha
best engines. A committee was formed for the purpose of d^
ciding upon the merits of the yarious engines, of whom the Dukq
of Sutherland and the Earl of CaitlmesB Mere working d
Captain Eyre M. Shaw, Superinteudent of the London Fira
Eni,'inc Establishment, being honorary secretary.

Before stating the results of such a trial we give the following
description of the various engines competing, which we have
compiled from the otdciBl report of the Committee and the 'En-

"The engines entered for trial were two by Messrs. I
Mason, and Co., of Upper Ground-street, Blackfriara Bridge;
two by Messrs. Merry weather and Sons,' of Long-acre ; one bj
Messrs. Easton, Amos, and Sons, Sonthwark ; one by Mr, William
Boberts, of Millwall ; and three American steam fiie engiu
all, we believe, yirtually entered by Messrs. WelHngton Lee a
Co. of Cannon-row, Westminster, although one appeared in the
name of Butt and Co., and another in that of 'Steam Fire En-
gine Company, Manhattan, No, 8,' New York. Messrs. L W.
Gray and Son of Limehouse, also brought an engine upon tl
ground yesterday morning, and the engine exhibited by Mesen.
Merryweatber and Sons last year in the International Exhibitinn
was also present, but weighing lather more than three tons, v
^excluded from competition.

Messra. Shand, Mason, and Co.'a large engine weighed 67
cwt 1 qr., without ooal, water, hose, or other gear, the extm
weight of which is not considered by the committee in their
limitation to weights of 3 tons and li ton, respectively. The
boiler is upright, 2 il. 8 in. in external diameter, witli, we be-
lieve, 296 flre-tubes, of brass, I in. diameter, and presenting, to-
r with the submerged smoke-box, 108 square feet of heat-
ing aurfaoft The fire-box is graduaUy enlarged below its junc-
tion with tlie barrel, being 3 feet 9 in. in outside diameter at the
bottom, and presenting I9| square feet of heating surfaca The
whole height of the boiler (barrel and fire-box) is 6 ft; tiie
steam apace 7 cubic feet, the water space 4"52 cubic feet (28^
imperial gallons). The tubes are pitched very cloaely, the clear

FiBE Eng.] SUAND'S fire excise. 209

between them being, we believe, but ^ in, but inHtead of
lupying the wbnle circle of the tube piatee, th«y ore airangcd
four symmetrical groups with a considerable clear w&terwuy
se groups. The smoke-box is eurrounded with a
iter space, and the water rises above it so as to surrciimil the
limney. In order to diminish the qaantitj and weight of
kter carried, it is not permitted to come in contact with the
aurfaoe of that part of the barrel of the boiler immediiitelj
iding the tubes, but is kept 2 in. or 3 in. away, all round,
a th'"" partition placed annularly within the l>oiler, and
[Lily joined below to the barrel itaelfi while the top of the
bncloaure thus foimed is open to the Bteam, which thus 6nds its
way down a considerable distance below the water level. The
barrel of the boiler is fastened to the fire-box by rings of angle
faced and secured by bolts and nuts. The smoke-box
put in in the same way, and thus the boiler may be
liecea in a short time, and without the least injury to
ly part. The water space around the fire-box is veiy narrow,
we believe, than | id,, but, as a. whole, tlie boiler curries its
water veiy well indeed. The framing of the engine is formed
of two deep slabs of wrouglit-iron, supported on easy springs,
the wheels being large for fast tntvelling. The fore wheels are
combined in a wroughtiron fore-locking frame. There are two
horizontal steam cyliiidei's, placed siiio by side, the bore being
B^ in., tbepistons of 9 in. stroke, working each a double-acting
gmi-metal pump of 7 in. boi«, the aiva. of the steam pistons to
that of the water pistons being as 1475 to 1, tbe stroke of both
steam and water pistons being the same. Tbe water passageH
are of gun-metal, the pump valves being of india-rubber disca,
having an area of 12141 sq. in. and | in. lift. The suction
pipe was 4 in. diameter, hose 2| in. diameter. Slotted cross-
heads are employed to give a rotary motion to control the length
ke, steady the action of tbe engine (fly-wheels being ap-
and for working tlie valves. TTie ordinary speed of the
le is about 120 revolutions per minute, tbo cranks of the
shaft being set at right angles, and a large'nir vessel
d to give a steady jet. Tbe ordinary working steam-
3 130 lb. per square inch, although this wus not kept
tl The boiler may be Sad by either of two feed ^uint;is

I

I

I
I
I

210 ENGINEERING FACTS. [Div. IT.

or by a Giffard's injector. The steam from the cylinders vt
turned into the chimney, the orifice of the blast pipe being made
BO as to be easily varied in size. A single jet or 'blower' of
Bteam may be also turned directly from tlie boiler into and up
the chimney. This is of great advantage is starting, as, after
Bteam of, say 15 lb., has been once raised, a strong drauglit
may then be obtained, thus raising the pressure qnickly to 100
" or 150 lb.

Messrs. Shand, Mason, and Co.'e small engine weighs 29^
t. Its boiler is of the same construction as that of the engine
just described, the diameter of tlie barrel being 25 in., and that
of the lire-box, measured at the bottom, 34 in. The height of
the boiler is 4 ft. 6 in. The small bra.sa tubes, 12 in. long, pre-
sent 48 square feet, the heating surface in the fire-box being
lij- square feet. The water apace iu the boiler is 16J gal-
lons, or 264 cubic feet, the steam space 3"62 cubic feet. The
working pressure is 160 lb., although 180 lb. has been reached,
the boiler having been proved to upwards of 300 lb, A single
feed-pump and an ipjuctor are providei There is a single ve^
tical steam cylinder, T in. iu diameter, the piston having a stroke
of 8 in., and being directly connected by two piston rods to the
plunger, 6| in. in diameter, of a bucket und plunger pump, 9 in.
in diameter. Tlie area of the steam piston to the displacement
by the plunger is as 1 '1 2 only to 1, while the area of the piston
as compared with the dilference between the bucket and plunger
is as 1'32 to 1. This apparent difiereuoe is compensated by the
aeetioD of the piston rods. The pump, and the parts eonneeteil
with it, are of gun-metal. The plunger is hollow, and a connect-
ing rod, jointed at its lower extremity, turns a crank shaft which
revolves between the two piston rods. The crank shaft carries
ft fly-wheel and an eccentric for working the valve. The auc-
tion valves are in the form of india-rubber discs 2| in. diameter,
seven being employed, and having a t'ltal area of 21 square
inches with § in. lift. The delivery valves are similar, but only
sis are employed. The suction pipe is 4^ in., hose 2| in. The
air vessels are very large, comprising a roomy space around the
pump barrel, and n tall cylinder besides. The framing of the
engine consists of two parallel steel tubes, apparently alwat
' ia. in diamotcr, polished outside, and serving within as ra-

■j^EAM FirbEnc] MEIiia'AVEATIlEK'S STEAM FIBE ENGINE, ill

ceptaclos for the branch pipes and tire iroiia. The wlicels ore

large, those in front being fure-luuking, and easy springs atv

used, both the ordinary plate springs and spirals being fitted

r the axle of the lorgLT wheels. The ordinary miiuber of ro-

Bvolutions of the engioe is said to be 1 60 por iuiutit«,

Messrs. Merry weather's lai^ engine weighs, we understiuid,
I tons 1 8 cwt. 1 qr. 7 lb. Tlie construction of the boiler is such
ihat, after having been once £Ui?d, it cannot be entiri;ly tinpticd,
Uid thus with a quantity of wnter in the tubes estiuiuted Ui
■j 3 qre, 1 lb., the weight, aa taken, waa 2 tons 18 cwt. qrs.
This engine is named the Sutherland. " Tlie boiler is of
e vertical tubidor description, having an outer Hheli of lionio-
s ntetftl .^ in. tliick double riveted. The tube and tojr
plates are of Lowniooriruu ^ in. thick, lliameter of hIioH 3 fl. G
., height 5 fL The arrangement of the tubes in this boiler, which
E similar to Perkins' one, is as follows: — The tubes art! of
solid drawn copper, and attached to the fire-box crown, so that
pthey are filled with water while the fire circulates around them.
To ensure a proper circulation, a centre tuhe, open at both eiidfl,
is introduced into the water tubes, having its lop fined out like
a funnel, so aa to deflect the steam currents out of theli' course
and permit a free course to the entrance of the water. By this
means, a perfect circulatiun of water in the tubes is maintained,
(lo much BO, that the greatest available heating siuface is much
augmented by the superior otrculation. The tiilses are closed nl
the bottom end, being simply suspended from the fire-box crown,
while the heated air, &c., escapes by a centre flue into the chimney.
The total tube surface is 192-6 sq. ft., while that of the fire-box
i« 14'i5 sq.ft. The fi-atoing of the engine is of angle iron. There
are two horiJwntal steam cylinders placed side by side, eacli of
8^ in. bore, the pistons having the usual stroke of 24 in., and
working directly the pistons of two double-acting pumps, 6J in.
^in diamet«r,-and of the same stroke, the ratio of tlie area of the
a to that of the water pistons being as 1983 to 1, or veiy
mearly 2 to 1. No crank ^laft is used, the steam valve of each
Icytinder being worked imm the piston rod of the other. An iii-
nious arrangement — too much so, we almost fear — is employed
D prevent the pistons from striking the cylinder covers, and tii
e the proper going of the pistons, ot, in other words *o kee^i

ENGINEERING FACTS.

[Div. IT. 1

phem in tlie same relative poBitionH to eacJi otlier wliinh tliey fl
iwould occupy if connected to cranks at tight angles 1/7 each other."
e Buctiott valvea of the piinipB are of gnu metal, imiia rubber I
ced, 10 in. long, 1'375 wide, and having a lift of 1 ia ;
■total area being 13'T5 aq, in. The delivery valves are similarly I
Bonstnicted, 10 in. long, 1'26 in. wide, the area being 12*5 sq. ii
uid the lift 1 in. bore. Size of suction pipe 6^ in., hose 2^ in. 1
Mossra, Me fry weather's small engine, the Torrent, weighed 30 I
[ ewt 1 qr. 12 lbs. The boder is of a similar description to their ]
I Ui^r engine, being composed of an outer shell of homogeneoui

metal full J in. thick, 48 in. high, and 28 in. diameter. Top I

f and tube plates were of Lowraoor -f^ in. thick The tubes ven \

of solid drawn homogeneous metal, having a total surface of S7

the fli'e-box surfiico, including flue, being 75 aq. '
The water apace of this boiler, when at work, contains from 1 6 to
30 gallons. The steam space has a capacity of about 4 cubic ft. ,

I is but one steam cylinder, which ia placed horizontally,
the diameter being 6^ in., the stroke 13 in., and the double I
acting pump, worked direct at the eame Btroke, 4f in, Eatio of j
steam and water areas, 1"87 to 1. This engine has no crank
shaft. The piston rod works a very small slide valve, which
admits steam upon a piston valve answering as the main valve."
The pump valves were of gun metal, leather faced. Suction, 9
in. long, 1*0633 wide, having a lift of 1 in. IJelivery 9'6 in.
wide, 1 in, wide lift, 1 ia bore. The suction pipe was 3^ in.
diameter, the hose being 2^ in. diameter.

Messrs. Easton, Amos, and Sons' engine, the Sabrina, weigha

2 tons 1 S^ cwt., its original weight haying been rather more than

3 tons. To bring it within the prescribed limit, the fore wheels
were made to serve in place of the larger pair, and their own placi

I was filled by a still amaUer pair. This engine was designed ii
k almost every part, we believe, by Mr. "Wellington Lee, formerly
f Hew York. The boiler is upon Messrs. Lee and Larned'a
patent, consisting " of a central furnace BI^TOunded by a shell of
rertical water tubas 2^ inches; around this is a steam chamber,
which, in ordinary work, is filled with water to about one-thiid
f its height; from this chamber deijenda a flat water-space, the
Bonnection being made with the steam drum by a series of 2J
i vertical tubes, a aeries of abort 2^ in. igaaa Imle^odently of

■I FiiiE ESG-I F.ASTOK ASD AMUS' F1RJ: KStMSK. 21.i

a through the suspeiid«<i slab nud eteam dmra iiK<pecliveiv,
A series of ^in. tubes p&s^ from th? su8p«iidoJ slab to the watvr
bottom, into which the bottoms of the outer tubes are secured.
Made of gun metal and stei:!, in coiijiiiictioi) with beet Lowmoor
iron. Tlie tube surface is 173 aq. feet, while the fire-box Burlsce
is 37 sq. feet. The quantity of water contained in the boiler is
about 41 gallons, the stcom-space being 11050 cubic incltee."
Tbe fruming is formed in & single forging of some difficnlty and
considerable iugeuuitjr, There ore two horizontal stccm cyliujera,
the pistons working double-acting piunpa of the Game etrokv.
The airangemeut, known as the duples pump, ia that of Henry
R. Wortliington, of New Yutrk, and has been patented by Mr.
Lee in tlila country. The steam cylinders are 9^ in. in diiuueter.
the ]>ump9, during the trial, being of 6^ in. borc, although they
may 1>e changed in about twenty minute^ to a bore of 6^ iu.,
where greater forcing power, irrwpective of volume, is required.
The engine is fitted and intended to work with either of th^
two sizes of pumps, as the particular nature of the work may re-
i]iiirQ. XhQ atrgke of tbe pistons i»t 8^ to 9 in. WitJi the
" duplex pump " no crank shaft is required, the piston i-od of one
..■iigine working the valve of tbe other, while separate eteaiu and
exhaust ports are employed, and both pistons ciimplet<;ly cnsliioned
by compressed steam at both ends of the cylinder. The oi'dinary
working speed is 1 50 double strokes per minute, hut tile engine
has been driven (not on the pi'esent trial, however) at npwMda
of 350 double, or 700 single, strokes of each piston. Tliia was
with the Sj in. pumps, the ratio of steam to water with this size
Ijpiiig as 285 to 1, while with the 6i in. pimips the ratio is
^^'136 to 1, tbe area of piston rads not Iwing taken into account.
^Kfi a private trial of this engine a plate was placed across the
^^■Buth of tlio ail' vessel, shutting off the access of water to its in-
^Hlraor. The engine conld not thiis be driven up to its full speed,
not was the jet very steady, yet it was very niucli nioi'e so than
would bave been supposed.

Mr. Roberts' engine weighed 39 cwt. 1 qr. 4 lbs., "and thus,
although apparently intended originally as a. competitor in tbe
B of 1^ ton engines, had to work against those of 3 tons,
a boiler, the body of which is 30 in. diameter, 2 fL deep,
4 iroa full y^ in, thick, tube plates are bare j in. thick.

r

I

au ENGISr.EKlNG FACTS. [D.v. IV.

Tlie fire-liox is fortn»l of a. circle of 29 vertical water tubes I
ill, in diameter and 2 ft. loug, these being surronuded by a. thin
sheet iron casing, while the Ixidy of tlie boiler contains 248'
tubes j ill. in diametiT and 19 j in. long between platea The
whole tubular siirfece ia 118 square feet, the fire-box surfuea
being 23 feet. The quantity of water contained in the boiler is
13^ gallons, the contents of the steam space being 6507 cubic
inches. The cylindet is single and vertical, 7 in. in diametfti
■with 13 in. stroke, with a cross-head and side rods working
down to one end of a bell ciiuik, from wliieli is worked one of
Mr. Koberta' patent double bucket pumps, 9-J in. in diameter,
and ii-ith a motion of 3^ in. on each bucket, one double stroke
I'f the steam piston thus clearing a cylindi'ical water space 9^
diameter and 6^ in. long. The suction and deliveiy valves of tha
pump are of india rubber, having an area of 12-17 ia, and
of i in. Tlie suction pipe ia 4 in. diameter, the hose ii
2^ in. diameter. From the bell crank- a connecting rod drives
a small fly-wheel, the shaft of which carries the eooentiic for^
working the slide valve. The framing of this engine is of light
angle and strap iron. The boiler is fed by a pump, a araa"
jector not having been found to work well. The main suction
and delivery valves are connected, by Mr. Roberta' regulating
apjmratiis, bo that the amallest possible streams — less than -j'ntli
inch ia diameter — may be thrown if required.

The engine Victoria, entered by Messrs. Butt and Co., was
made by the Amoskeng Manufactuting Company, of Manchester,
New Hampshire, TT.S Its weight ia understood to be 6,100
lb. The boiler ia upright, with 313 fire-tubes, 1^ in. outsido
diameter, and presenting 183^ square feet of iieatiiig surface.
The flra-box has 16^ square feet, the Bmoke-lwx is submerged,
the water level being above it. The boiler is 36| in, in
meter, and 5 ft. 5 in. high. Its water space ia given a)
cubic feet, or 62^ gallons, while the stc-un apace ia 8J cubic
feet The framing of the engine is a hollow gnn-motal casting,
BOTving aa air vessela, water ijasaagea, Ac, The fore wheela
cannot fore-lock, and this remark appliea to all the American
engines, although it was formeriy the custom in the States to
fore lock tlie wheels. The single vertical steam cylinder ia lOJ

ill MaiJieteT, the piston of !2 in. stroke working directly a

f

^^double-acting pump of 6 in. bore, the ratio of steam to watrt
being aa 306 to 1. The ordinaiy nmnber of strokes was given
as 200 per minute. The suction and delivery vulves are of
india rubber, numerous and la:^e, giving the same area as the
bore of the pump. The litl is j- in. The finish ef tiiia ei^ne,
as that of all the American engines, was of a superior kind,
even after making due allowance for its showy and rather bizarre
character.

The Alexandra, entered by Messrs. Lee and Co., is by the
same makers, and is of the same general construction as the
Victoria, The weight is given as 3,100 lb., the boiler 27 in. iii
diameter, having 199 vertical fire tubes, 1^ in. in diameter, and
presenting 97^ sqnare feet of surface. The fire-box has 9J square
feet of surface, and the submerged smoke-box 9^ square feet,
^^.TBter space 4'23 cubic feet, stesjn space 4'33 cubic feet. The
^^uongle steam cylinder has a bore of 7| in., the piston of 9^ in.
^^Rtroke, working a double acting pump, 4^ in. bore, and of the
^Bteme stroke, the mtios of steam to water being as 3'33 to 1.
^^ The ordinary working speed of this engine ia given as 300 re-
volutions per minute, the steam pressure in all the American
engines being about 100 lb. Both this engine and the Victoria
^^^ave slotted cross-heads and fly-wheels.

^^L The Manhattan is of the same general construction as that ex-
^^Hiibited last year by Mr. Lee in the nave of the International
^K^xhibition. The dimensions are larger, however, and the
^^ weight, 5,300 lb., correspondingly greater. The boiler is of thu
same construction as that of M^essrs. I^ton, Amos, and Sons'
engine, having 213 tubes, a part of which are 3^ in., and the
j^^ others ij in. in diameter, the lengths varying from 3 in. to 4
^Kft., the tuba surface being 133^ square feet, the fire-box surface
^^BAS-^ square feetj the total heating surfnoo in contact with water
^^^nd steam being 182 square feet. The water space is 38 im-
perial gallons, steam space 7^ cubic feet. The diameter of the
boiler is 36 in., and its height 5 ft. 5 in. The single hori-
zontal steam cylinder is 9 in. in diameter, the piston having an
8J- in. stroke, and working a rotary pump up to 400 revolutions
r minute."

Messrs. Gray and Sons' engine weighed 38 cwt, 1 qr. 4 lbs.
Xlw piLucipal feature of this was the boiler, which is a cyllndei

E eno.] lee and co.'s fire BNGINF.

IS ENGINEERINO FACTS, [Div. IV.

JO in. diameter 26 ia. long. Slowly revolving over the fire-
grate on two trunnions lired at its ends, and containiDg 38 inm
ubea, of 3 in. exterual diameter, and 28 ditto, 1 4 ia ditto ; the
helt is of steel plates, ^ in. tliick, and ends of ditto are ^ in.
jiwmoor. The boiler ia enclosed in iron casing lined with fire-

wiiich patent, by the way, is not very valid, seeing the veij same
arrangement was patented many years ago, and an illustration ia
to be found of it in some of the hack volumes of the ' Praetiml
Meehamce' JoamaV The engine has a steam cylinder of 9^ in.
diameter, the water cylinder being 7 ia diameter, both having
B stroke of 8 ia, the pump being double-acting.

In the foregoing description of the different engines, excellent
examples are to be found of hoilera of comparatively large power,
and occupying little space, being at the same time capable of
standing high-pressures and embodying little weight In many
cases homogeneous metal has been the material employed, and so
ar with good results.

Proceeding now, however, to the resulta of triaL

LAEQE CLASS.

PIE3TTEUL. (ForMr™i«p.21B).

Ddivering 1,000 QaOom into a Tank at a troe diUmitt qf 67 ft. and 27 dtg.
from the horiion. Tht aattr iathe Boiler iemff CbM B>*«1 (A« tignal «(

Steam, Preaimv of 100 lb. on the »g«i« inch.

Ko.

NaniBS.

Time of

Timeot
filUnB
tank.

TotnL

RIMAUS.

1
S
S
5

Easton anil Amos,
Menyweolher,

ghand and MasDii,
Butt SDd Co.,
Roberts,

13 H
10 25

10 51
Ifl 30

11 ia

B 16

9 7

12 19
8 «
20 SJ

min. Bee.

19 30

20 7

23 -10
23 18
32 i

rautnloi. pipe .ibokod. Ml
I off working .bout* min.

1.

^

J

Pjrk Kyr..]

TKIALS OF STEAM FIRF. K

V-fJlNES,

1

1

n

'Si

e-3

»=1

•pajsitpp

s

^

^

§

!i

mollis JO -ofj

2

£

S

I

■satasasH

S

s

s

S

S

=

nioflsiJtnv

1^

s

3

3

3

3

»

^

^

^

c

S

BtiDTWP aity,

•a

"

«

■"

"

^

_

s

_

\

,q8iaq[ra!waA

'

"

-

'

'

TMJ

s

3

s

S

5

3

■oaiupai

JB,M q=R*

5s

2

2

s

S

S

■Binon p sns

>. 1

•«"1 P -HSni

^S

3

S

3

s

s

"

1

1

s

=

=

s

s

s

1

s

=

-

s

p.

-

*

^

tn

W

J^

^

■FWjo-otJ

S

j

3t

^

5

1.

_l

1

s

ll

i

E

1^

J

-

=.

«

-

-

.

1

Ik'

.1

■

818 ENGINEERING FACTS,

Rexaeeb.

1. Pire lighted 1.1m. 55b., gauge moved at 4.8in. 20s., eogine Btiirt«d
4. 12ni. 37h. , water drawn in about 10 revolntions, pompfl not pruned, ralre ^
leaked alightlj, and engine worked ssitisfactoiily in every respect.

2. Fire lighted 11.25m. 16fi., gunge moved at U.Siia. 539., engine al&rted
ll.BTm. Ta, pompa primed at 11.45m. 4Sb., drew water at li.4Tnu, water f
thiuugli nu^e 11.4Sm. 59., in hood at 11.411m. 19fi., shifted noule, 31 mini
dela;. Hi^h wind.

3. Fire lighted at lI.ITm., started engine at ll.SSm. Stls.

4. Fire lighted at 5. S.'im. lOs., started engine at B.Bm. 20a., repeatedly
~~~ elide valve not acting, and stopped entirely at 6.4flm. from cylindi

h

breaking,

fi. Kre

2.1Sm. Ga.,

falUni

stopped entirely at S.Mia. IIK, from t

re lighted at ID. 51m. 143., gange moved 10.59m, 20b., drew water directly
m nu to 140 lb,, at 11. Sm. 45s, titopped two tuiaiUes, in&rted again, made '
revolutions, and fly-wheel broke,

TRIAL {F<rrTablto/la Trial ire p. 218,)

Steam Time of

Shsud and Hason,

Uerryweather, ...
Robert*, ...
Esstoo and Amos,

Verikal JH agaa
FOURTH T

Qreatest heiglit (krowa.

I Shaod and Mason . .

ShantMerryweatbet

Butt aniherta. .,,.

i FiBE Eso.] TRIALS OF STKAM FIRE EXOISh-S-

^ Itaali) vas in Buh o

Hlected b; the proprietor of the engine
.408.; 3t«un, Ulb. at 7. I'm.: got to work

"a KnoiNX -.—lAiiAei . . . . _ . ...„_... _._

w firea : T-S7m. , WH.t«r throDvh hoee : ovinff to some of bbf
■ ■ ■ -'-■ '-—VrlriaT could be

SHALL CLASS.
irring 1,000 Oalloru into a Tantal d true diglaact of 56/1., a
■J. fn^a tht Affruon. Tht wilfr in tkt Beiien bring Cnid vAoi (/
i tcoM ffiren to eommaict; tarh fftwiiM commtncing to tcork on alfa
iteam prauire of MtO lb. to Iht aguare ineh.

FIRST TRIAI-

Shaad and HsfloD

li.MH™h

EEC

OSD TRtAU

Niuae.

Steam at
begin niDB.

work.

filling

RkH ARILS.

i|»d»»dH»on

^••irfc.

8S
12S

ion

S' 49
S 50
B 17

Leakage remedied.

220

ENGINEERING FACTS.

[Di

'3^

I

*5 2

.e

m

*p91dAIl9p

8ao[];88 jo 'o^

^

00

00

'dJusBdjd

998I9Ay

o

00

kO

'ainssaid
ure9!)s

99BJ3Ay

5

00

o

00

•aozuoq

IS

to

domr^sip

CO
to

S

«o '
»o

"^ ^ ^

HI dacre<^Tp
|g^nozTJOH

'OAkVip 81

uiojj q^daa

CO

CO

*a|zzou
joazig

.S

.3-

tSBO

*a8oq
JO q^aaq

• o

^

^

•uado
sauaAipp

rH i-t 1-4

•

O' o o

•

a

O o c

W

rH rH t-i

o

J

o

rl (M

oc

a

•-3

o

J

f-i C4 CO

TRIALS OF STEAM FlUE ESGINES.

Laboe Ci^sh.

SuAU. Class.
lliissrs. Shand, llnaon, snd Co., first pnic
Uessrs, W. Lee and Co., Mcond prize

r i^ UBual, in such trials am the above, much diseensioa arosp,
lecially among thi)se who did not get prizes. As to the aocn-
i of the tests auii the discretion of the jiulgee, it is not niii-
e to enter into sny argunienta for or against such trials,
jtrring mther to lut the facts speuk fur themselves, as they
k ho useful to engineers who may he interested in fire
B constmctiiin.
a concluding this division we append the following siigg'.is-
e for improvement made by the ' Meekanie^ Maijaziiiu :' —
" In tbe steam Are engine, more particularly wjieu intondBiI
f«r service on land, we have a machine which must satisfy many
strictly exceptional requirements. In order tliat it may be use-
ful and admirable in the fullest sense of the terms, it must not
only be extremely light and portable, but of enonnoun strength
as well. Intended to work under the moat trying circumstances,
and at seasons when the calmest pulses are accelerated, and the
coolest heads lose their self-possession, it must be prepared for
Fough work and much knocking about Nothing but iirat-elass
■wnrkmnnsliip and materials can reconcile these incompatibilitiP!«.
Ere long, we tjiist to see steel take the place which wrought-iron
now bolils in the lii-e engine. It is already partially used, in the
form of piston rods and crank shafts; and there ia nothing to
preclude its enjployment in the shape of boiler shells and carriage
f'rameB. In cylinders and pumps, the use of homogeneous metal or
malleable cast-iron, would effect a very considerable reduction of
weiglit, and positively add to their powers of endurance. The
principle of annealing articles of cast-iron required to sustain
great strains, ia better uuderstood daily; and a steiun cylinder or
pump valve, one-fourth of an inch thick, so treated, is stronger
thsQ one of twice the weight left as it comes from the moulder's

ENGINERRING FACTS.

[Dir. IV, I

tiiisk. By tiiese means alone, we do not doubt that an imporbutl
rediictiiin might be effected in the weight of future enginesif
whilst improveinotit in the arnuigement of the working j
frames, and trusaeB, would permit a more equable distribution d
the strains to which the machine is exposed, and materially Hdill
to its longevity.

" Tlie principles involved are simple enough. In their adap-l
tution to the reqiiiiemeuts of practice lies the difficulty,
gives out its useful effect equally well, wLether a piston mov
fast or slow, so long as economy of fuel is not an object of dea
Hence, if weight v/ere nut a consideration, the s[ieed uf the ei
gine would be a matter of slight importance, and that veloci^l
be^ adapted to the description of pumps employed, could bif
adopted without hesitation. In order to secure portability, how- F
ever, in the highest d^p^e, with a pressure kept witiiin r
able limits, quiek - working engines are indispensable,
would, of course, entail no difficulty were the motion of watei M
manageable as that of steam. Unfortunately tliis is not I
case ; and, us a coiwequence, the steam fire engine requires U
be treated more as an hydraulic than as a steam machine,
are, therefore, inclined to prefer that principle of eonstructi
which permits a lung stroke of the steam, and a short stroke a
the water pistons. Such an arrangement is, perhaps, more Ukeqj
to secure a high co-efficient of useful effect in proportion to ii
fuel burned and the weight of the machine, than any otbc
High-speed engines coupled directly to the pumps, p
capable of doing good service, as oui' American frienda h&vf^
showed ; but we imagine, with a very considerable and n
sary waste of fuei Were it not for the effects produced bjfl
wear, the rotary pump, as adopted in the 'Manhattan,' wonl'
seem to be best of any ; and it is quite possible that this objeo
tion may not be found insurmouutable. Notwithstanding a ~
boiler, the admirable qualities of tliat machine, in everythi
concerning the engine and pump, were sufficiently manifest W«|
believe that excellent results would be obtained from a »'
arrangement supplied with steam by a generator, say on HrJ
Field's principle, of sufficient power. TJie rotary pump, howJ
ever, is condemned for the present by those best acquainted witbfl
,jto cApabilities; and it is, therefore, unnecessary to dweU fui

ku FiRB Eve] WORKING EXPENSES OF STEAM FIRE ERl^^H

Bctual remedy. If the centrifugal form is deemed ohjetSffl^^
p, there ctie man; citfaers open to our adoption — a rowltflca-
n of Pitcher's governor, for instance, miglit probably be usmI
ni great advantage. Tliese are, Ijowever, minor matters; and
pre have good reason to be satisfied with the progress made in
I last few ypars, we may safely leave tliis considcTation, for thi.-
bent, to those most intereEted. The ueeessity foi a fly-wheel
B crank-shaft is a more important questioB, on which great
mrencB of opinion exists. "We believe that its adoption sim-
nea the valve gear, gires steadiness to the motion of the
Mne^ and permits a considerable reduction in the spacii
ppied by the machinery — advantages not to be lightly

With regard to the working expenses of «team fire engines i\a
kpared with hand worked engines in America, the following
pnblished by the Amoskeag Manufacturing Company ; —
E*In regard to the cost of running a steam fire engine many
N)le have very wrung impressions, being led, by the reports of
I cost of BiflintaininR them in eome large cities when tliey
ba first put into service, to suppose that the expense must be
w great iu all cases. In these cities a regular 'fire brigade'
puployed, and tJie extinguishment of fires is a daily business,
H Uie number of men necessary to work an engine are con-
pily em[iIoyed and paid. But even here, as shown by the
Biic^ the use of steam engines has reduced the running ex-
t&ea of the fire depai-tment. Bnt in cities of 25,000 inhabi-
■b^ more or less, where fires occur perhaps not oftenet than
n or twice in a month, the expense of maintaining a steam
I engine is very much reduced; iu fact, a steamer in such a
W can be run at a less expense per annum than the usual
k of maintaining a hand engine.

B* In the city of Manchester, N.H., the fire department con-
k of three steam fire engines. We append below the expense
Running tliese engines onu yeui, taken from the city report,
B the expense of running a hand engine for the same period.
B cost of repairs is found by experience to be no greater on
l^eteam fire engines than on hand engines. The first steam
Hne, which has been three years in service, has not rei^uihid
■at to be espunt}i:ii u^iou it ii.< yi'1

ENGINEERING FACTS.

[Div. II

"A ateam fire engine comjmiiy ia cuinpuseJ of fourteen
all told, one of whom, acting as a driver and steward, ie con
stantly employed, reiiiiiining at the engine house with a pair i
horaea always ready to run out with the engine in case of a
alarm of fire. The other members of the company have otlic
employ nieuta, and tuni out only on an alarm of fire.

Steam Fiee Engines.

Dols.
Amoakeag Expend iturpa . SBi 33

Kire King, . 856 78
E. W. Hm-rington, 4flfl 09

" 'Jhe above expenae includes pay of members, team expenses,
cost of gas, wood, oial, and all necessities incident to servic&

" The Tl W. ifarrington is a second-class engine, atationed in
the outskirts of the city, ami was run cheaper from the fact that
no horses were kept for it hy the city.

"A firstKslass liand engine company is allowed to number,
all told, fifty men, and the members of the company are paid ai
follows i— -

I

1'[]1S1-CLA«

a Hand Eko

NE CottP

NY.

DoU

■2S 00

6S 00

men, at 18 dola. ecuih.

82S 00

60 men. Tntiil, . 08" 0(

" By this it will bo seen that in a city like Manch ester, wiih
20,000 to 36,000 inhabitants, a fiist-claas steam fire engine
be run at an expense not to exceed that of a firat-claaa hand en->
gine, while in service it will do at least four times the work.

" In the city of Boston, the comparative cost of running th»
two kinds of eugiuea is as follows, viz. : —

1 ulerk.

1 Btewanl,

3 leading hoaemen, at 1 25

" - -, Bt lOOdols, eaoli,

Tutil,

DIVISION FIFTH.

TURBINES.

The following intoreatiiig aii<l able article from the ' iJeeliamW
Muij'isiiie ' will fitmi an approiiriate introductioa tu this Ue^iiri;-
iiii'iit of tlie work : —

"The ulass of water-wheela, kuown by the general term 'tiir-
Ijjiie,' 8uppli(!8 UB with, perhapa, the most [iractically perfect
iiieaiiB to be met with in the arts, of obtaining the highest results
fi'om given mechanical eU'eats. To all inteiita and purpoaes, the
turbine is, if properly constructed, a perfect motor, capable nut
oaly of working under all sorts of circumstances and under tln'
most variahle conditions, but of invariably giving oat a high co-
ellicient of useful tflect aa welL Perhaps invented, at all events
first rendered effective and economical by Fourneyron, in 1837, j
it baa gradually worked its way into general fiivoui' solely by ita J
own marits. It is not easy to say liow many of theni are ut I
work in Great Britain at the present moment. Messrs. Willinia- 1
son, Donkin, Scliiele, the North Muor Foundry Company, andB
many other flrras, have, we believe, full employment found theml
in their construction ; while abroad their uat^ is even nioi'e exfl
tended than it is here in the fatherland of the steam-engine—fl

ENGINEERING FACTS. [Drv-

^^L the giaut who will scarcely Irook the presence of a coiuyK^Utii
^^K- within ilia domains. In France and Germany, the turbitii:
^^Kenjuya great iavour; the comparatively high price of fuel aul-
^^F iiig to some extent as a bar to the habitual use of steam nm-
1^^ lihineiy. In America, the ordinary vertical water-wheel

cluflively emphiyed — the breast-wheel being couaiilered beal —
until 1844. In 1843, Mr. Elwooil Moms communicated to the

» Journal of the Fmiiklin Institute, a tranaiation of Morin'
perimenta on turbines, which attracted couaiderable attention.
The year after, Mr. Eoyden, an engineer experienced
manufacture of hydraulic machinery, designed and constructed
liorizontal water-wheel for the Appleton Company's mill,
Lowell, in Massachusetts, which at once embodied several im-
provements on the Foumeyron arrangement, and may be r^ardeil
^as the first instance of this application of water-power
States, In 1846, the same gentleman cooatructed tin
bines, of about !90 horse-power eaoh, on the same general prin-
ciples ; the particular design being somewhat modified and im-
proved. It is said that the mean maximum effect of two of
these was found, by careful experiment, to ecjual 88 per c«nt c^
the tlieoretical power due to the fall — a statement which, pro-
bably, contains a slight exaggeration. The general principleB
and mode of formation which distinguish the Fourneyrou wlwvl
are so well uuderstoud that it would be superfluous tii dwell
them individually at length. The water, distributed in lionn>n-

»tal jets by peculiarly curveil vanes or guides, issues from the cir-
cumference of an inner fixed wheel, composed of two discs kept
apart by the guide plates, and passing through an outer annulu
wheel, fitted also with guides of a contrary curvature, puts it in
motion; its interiur periphery revolving as nearly as posaibit
contact with the exterior periphery of the inner or guide wheel.
This is the Foumeyriju turbiue in its simplest form. One of the
niost impiii'tant imprnvemsnts effected by Mr. Biiyden, was the
application ol the ' diffuser,' almost universally ailopted siiioe.
The invention is embodied in the formation of two large sta-
tionary discs without and around the wheel, the space between
winch at the inner periphery is very httie gi-eater than that be-
s of the wlieel at the part next to them. These
s curve annrt and outward, so that the s^^ace at their exi

».]

TURBISES.

■periphery is twice bb great. Tlie sectiun through which tlie
■ nnCer ]>ft£«es in escaping from the wheel ia thus enlarged in the
I ratio of one to four; hence its action shouM fall from 1 to l-16th
I 111 the Banie distance, ppovijed the wheel be aiibmerj^ed. Tlie
[ iitfect of this arrangement is to reduce the pressure on the escap-
f ing wHter, and thus inerL-aae the piwer aa though the fall were
iucreiaseil. The tlieoretical gain to be derived by this arrange-
mont is equal to about 6 per cent, on the whole power; though
from one caniie or another only 3 per cent is usnally realized.
Mr. Boydon suspt-nded his turbine from above, and was the hrst
to point out the expeiliency of employing very thin guide-plaleit
^md vunea. One of the greatest objections to the Fourneyron
wheel nnd its modifications is. that, being altraya submerged, it
i^ to 8i>me est«nt, iuacceeaible fur re[>airs or examination. It is
frequently far irom convenient to drain away the water, espe-
cially when more, than one turbine is supplied from the same race.
As early as the year 1838 this objection was recognized, and the
' Jonval ' wheel introduced to obviate it In^ad of revolving
outside the atationary guidee, the buckets in this turbine revolve
below them. Both' the fixed and moveable wheels are placed
within a tube of nufficient diameter, the orifice of which, plac
helow the level of the water in the lower race, ia so contracted
as tu allow of only the proper quantity of wat*r passing through,
due to the velocity arising from the difference of the two level,
above and below the turbine. By this arrangement the wheel
may be placed in any piirt of the height of the fall deemed most
(tcsirable; the necessary force and velocity of the water being
obtained by the pressure of the atmosphere on the upper surface
of the suspended liquid column. When the supply of water in 1
eut off by clfi--^ing the upper sluices, the wheel is left high a
dry for repairs, as the tube ia usually latge enough to aflonl ]
Ample space for a man to work in it with ease.

" Wlien the turbine is employed to render high falls available,,

the foot-step of the vertical spindle often gives much trouble, i

well from the difificulty of lubricating it properly, as ftt)m tlij

great weight which it has to suRt.un, and the high speed e

. which tlm shaft revolves. At St. lllasier, in the Black Foresf

[ ft wheel only 13 in, in diameter is put in motion by a

^ of water 35i ft, Iiiyh. Whether a,lV 1.\w -^nwwitft •J.-aif, t« yj

930 ENRISEERING FACTS, [D(v. T.

vast lieiglit is retiJpred availalile or not, we cannot say. The
wheel makes 3,200 tuvolutiona per minvite, driving 8,000 wutvr
«pi)>d.les, vrith t)i<i nccessuiy machinery fur slubbiug, roving, &c
Fifteen hundred revolutions per minute are liy no means uncom-
mon with laiger wheels, Mr. Boyden, in America, and Mr.
Mallet, in tliia country, cut the Gordian knot by hanging the
revolving ring and ita shaft, and aU the weight of water upon it,
from a ilrg of conical rollers above the peu-trouj;h, running be-
tween two faceil-up iron plates, the central toe or step being used
merely as a atcadiur. When the footstep is retained, the beet
practice is to form a cavity in the end of the shaft, which, in fitted
accurately to a hardened steel pin, projecting upwards, firmly
lixed in the base uf the wheel pit, on which the entire weight is
sustained. The proper shape for this pin and its corresponding;
cavity has been made the subject of much mathematical disqiii'
I siticin. Oil is usually suppKed throutjh an aperture drilled up
I the centre of the pin, by a very small force-pump, put in motion
by an eccentric on some slow running shaft in the mill above.
In the great Faimioiint Jonval turbines, intended to supply water
lo the city of Philadelphia, the central sitafta are supported on
stout cast iron columns, bolted down to the iron bottom of th*
draft box or vertical tube. A socket, resting on the top of thii
column, contains a circular block of lignum vite^ 15 in. in itio-
meter and 8 in. or 9 in. thick. Its upper' surface is niunded to
a partially spherical shajie, and a few spiral grooves are cut in its
surface to permit the entrance of water, and thus secure constant
lubrication. A cast iron socket, hollowed out to fit this block,
is keyed on the lower extremity of tlie vertical shaft, thus form-
ing the bearing. These wheels are, perhaps, the largest of the
kind in the world, being not leas than 9 ft. in diameter over the
buukets ; each wheel, we believe, drives a nearly horiEOntol double-
acting pump, 18 in. in diameter, and 6 ft stroke, intended to
make twelve double strokes per minute wlien pumping agMnst
the head of water in the reservoir.

"The construction of the turbine suggests some of the most
cu Hi plicated problems in hydraulics, and theory scarcely yet
affords the means of solving thi'm. Pi'actice alone supplies us
with thoroughly trustworthy results. From tins reason, there in
Jittio doubt that the i^tatementa of Ike utiual effect realised from «

F

|l^^pveii full are frequently oTer-estimaU-il, llie nuaiitjly of wuttr
paasiug thraugii the wheel being really in excess of that BSSiunml
&oni calcalation. Still, making every allowance, there ia uo
doubt tliat with proper care turbines uauaEy give out a higher co-
efficient of useful effect than perhaps any other moving power in
existence. At first sight, it appenra that the entering water ebon lil
impart a severe shock to the curved bactets which oppoae ila
motion. This disappears, however, when the wheel moves at »
proper velocity. Under correct arrange menta, the water entei^
the wheel without impact, and passing along the whole length <if
the blades which constitute the buckets, and exercising a presBuro
i every part, whereby its velocity is constantly reduced, while
e direction of its motion is modified by their curve, it Anally
e the wheel with an insensible motion, being deposited as
t vere in the tail race, Irom which it flowa in obedience to the
r of gravitation at a velocity detenuined by the inclination of
s floor on which it rests. In order to secure this action, the
boat extreme accuracy of workmanship ia absolutely essentiaL
I is useless to set out the proper curves with a strictly matho-
itical precision, if these are afterwards departed from by an
( method of practical construction. Theoretically, the
rves should have no thickness; and although this de-
fideratuni is unattainable, we can, at all events, a]>proach almost
indefinitely near to it. It is not easy to secure the necessary
accuracy of fitting through all the details, by hand labour. The
e extended use of machine tools specially designed to carry
i in view, and of cast st«e1 as a material of construc-
I, may do much to reduce the first cost and improve the per-
a of tlie turbine ; the latter imparling that stiffness and
rength which, cannot be obtained frtim the use of sheet-iron.
k ia impossible to over-estimate the importance of correct form,
Ind it requires little reflection to show how easily thin guide
'plates may be deflected by the pressure of the water when the
wheel is at work, although, when at rest, their shape may leave
nothing to be desired. Machuie tools would rapidly and cheaply
impart that smoothness of surface and delicately beautiful cur-
raturo tn the guide plate and buckets, on which the efficiency of
^ a machine almost wholly depends." — ' Meckaniaa' Muf/azine,'

FITTING UP OF TrBBIKER.

^

231! ENGINEERING FACTS. [Lev

Tlie fuUowiiig article oil turbines and the friction of water ii
tlie various porta of a turbine appeared in the ' Engineer:'—

" In the caee of a small supply of water with coiieitleTable &I1—
a case in wliich the advantages of a turbiue over any other D
are becoming better understood every year — it ia necessary b
bring the water down to the turbine through a pipe. If there i<
u supply of, say, 400 cubic feet of water per minute, an unpro
fessionjj man is apt to suppose that only a pipe capable
charging that quantity of water is wquired. An engineer is wall
enough aware that a large allowance must be made for tlie fi
tion of the water in the pipe, but the exact determination of tli(
discharge and loss of head due to friction is not always easy, evm
to those whose pursuits really require that they should I
thoroughly conversant with such mutters. Frofessioual me
therefore, who ao well know the paucity of elementary scientilie
knowledge among those who delight in calling themselves 'prac-
tical men,' will readily pardon the introduction and application
liere of the rules fur estimating the flow and friction of water in
jiipes. Eytelweiii's formula for the flow of water in pipes at then
full dlschatge is ^ follows—

2356 V rf'
4/1 + 50 d

- discharge

in cubic feet per minute, I, h, and rf being, respectively, tha
length, fall, and diameter of the pipe in feet Where thi
length is considerable the divisor may be taien os'K-r-.

60 diameterB allowed for bringing the water 'into train' being
disregarded. The square root of the fifth power of the diametei
of the pipe will be quickly found by those in the habit of refers
ring to a table of logarithms, and to those who are not, the cslon-
lation itself ia not necessarily very tedious. It will save time,
ill many cases, to remember that, for a pipe 1 fL in diameter, the
square root of the fifth power is 1, and to make a note that^ ioi
a pipe 6 in. in diameter it is 0-177 nearly; tor a pipe 18 in. ia
diameter 2765, fora pipe 2 ft in diameter, 6'667; 3;fl., IB'SSSj
d 4 ft,, 32. Thus, to find the discharge of a lomg pipe, in

TirRSiKta.) WOEKINO VELOCITY OF TUItniXF.''. aM

'■■ibic feet per minute, tlie square root of the fifth power of tbr
iuiemail diametei' in feet is inulti)]lied b; 235G, atid tho ptxxluct
j^ divided by the square root of the quotient obtAined by dividing
the length by the fall. Mr. Beanlmore'a valuable i/yrfmn/ic
Tables, published by Mtasrs. WntiTluw, contain a table of c(pn*
i-tiints, by Mr, Jauea Leslie, CE,, from which the discharge mny
he sttU more readily obtained. If we take fur illustration a 1 tt.
pipe, 500 ft long, and falling 20 fl. in that distance, we shall
find the dischatge to be, by the fornmla already givun, 471 t'libic
I'r.'et per minute. This discharge, on a 20-ft. fall, would, were
there no loss from friction, correapond to 17 8 horiw-power, of
which about 14 might be eoimted upon in practice with a tiir-
liine. But 471 cubic feet of water discharged per minute through
;i 12-in pipe must move

■78S* : I : i tn : 59»7 ft.
per minute, or, say 10 ft. per aecond, and the friction due to this
velocity must he allowed for before the available power can he
known. The formula generally adopted for estimating the fric-
tion of wiiter in pipea ia that of Wiisshacli, and is as fullnws : —
I 001716 ) 1, v<

" From this formula Professor Thomson has compated a tahje
showing the friction of water in pipes of different diameters nu'l
100 ft. in length, at velocities ranging from 1 to 7 ft. per seconil.
Tlie last named vehcity is, perhaps, the highest practically mtt
with in pipes; hut, in tlie case already asBmneil, the velocity is
greater than ia provided for in Professor Thomson's table, and we
must apply the formula ; II being the head rcquii'cd to ovei'come
the friction, L the length of the pipe, D the diameter, and V the
velocity per second, all in English feet. The head due to fric-
tion will he found to be 15"36 feet, leaving but 4'64 ft,, or less
than 4 ft. a in. of the whole head of 20 ft., avaikble for driving
a turbine. Thus the whole theoretical power obtainable from
the water discharged through a pipe 600 ft. long, 1 ft, in dia-
meter, and having a fall of 20 ft, would he but 4'1 horse-power,
of wliich a turbine would give only about 3 horse-power. We
may mention, while upon this subject, that the theoretical hoi's!!-
power of a streun is moet nadUy obtained by multiplying thu

I

I

I

2^4 ENCINEI!RlNG FACTS, [Div

numteidf culiic feet of ivLitcn' delivered per lainate by the efTectir
fall in fuet, aud diyiding the product by 629. Tlie power pra
ticttlly obtainable with a good turbine will be found by dividin
the product (obtained as just described) by 700, correapondin
to an efficiency of about 76 per cent.

" We have thus seen that, if » pipe be allowed to delivei
its full discharge, very Httle power will remain in the water s
the point of delivery. Indeed, without calculating t
1 ms <]f head due to friction, it is only necessary, in thi
aumed, to find the head corresponding to the velocity at whi«'
the water is discharged from the pipe. This is 10 ft. per secont
for we have seen tliat the tlow throu};h the pipe is at the rate C
599 7 ft. per minute. The he^ht in feet corresponding to thi
velocity will be obtained by dividing it by the velocity due tl
1 il. of fall, and taking the square of the qunticnt. The actiu
velocity of water falliiij; in the air ftom a height of 1 ft. is aboi)
B ft per second, and ^ = 3, which, squared, gives 4 ft. as tl*
Lead oorrespondiiig to a velocity of 10 ft. per second. This r
c^ult Ls doubtless very near the mitrk, and when the pipe was di
oliarging up to its full capacity about 4 fL of the whole fall ti
20 fL would be the most that could be counted upon for thi
purposes of a water wheel.

"Let na, now, assume that an 18-inch pipe is employed will
the same length of 600 ft., and a fall of 20 ft. If the supplj
of water were sufficient, this pipe, having 2^ times the area a
one of 12 inclies iu diameter, would discharge 2'7S5 times Bi
much water, the square root of the fifth power of 16 bein^
2-765, while that of 1 is 1. Thus, the 18-in. pipe would d"
charge 1297'6 cubic feet per minute, and at a lineal velocity o
12 '24 ft. jier second. But as we are dealing with a supply (
water equal only to the full discharge of a 12-in. pipe, or 47
cubic feet per minute, tliia, in an 18-in. pipe, would move witb
a velocity of 4'44 lijieal feet per second, and the head requisite
to overcome the friction of the water in the pipe at this velocity
would Iw 2'3 ft,, leaving 17-7 fL available faU. With a S-fli,
pipe the velocity of flow would be but 2J fL per second, anf
the losa of head but -6125 fL, or less than 7^ in. in 20 ft. ; b)
the saving of 1 7 ft, of fall might not, perhaps, compensate fi
the diSoreaoe of cost between 5tlQ &, <j^ VS)-\c_ ^igo «

S.1

roWKR OF TirRBI.VES.

same length of 2-ft. pipe, the difference of weight, with-j
ijiet*! in the pipes, being 7 tons, and the difference of cost Ixiing
therefore from £30 to £40. The aarirg of I'T ft additioual
fall would, with 471 nibio feet of water per miiiTite, correspond
to a gain of upwards of 1 actual horse-power, and in manj eitua- l
tiona this would be more than an equivalent for the interest upon ,
the additiontil weight of pipes. In cases where the water can
B brought down a vertical pipe for the whole height of the fall,
■ 6 diffcreoce in weight between a large and a siuall pipe ia of '
s practical iniportanc* ; and in anch a case a pipe of at least i
T times the sectional area of that which would just dischargii J
e given quantity of water should be omplojed." )

f The following letter, addressed to the ' Eiiffinefr' by the well- j
TTO inakera of " Vortex or Whirlpool Turbines," Messrs. Wil-
1 Brothers of Canal Ironworks, Keudal, was called furtli
f the above article: — " We beg to submit a few remarks, hav- jl
J re'erenee to the article on Turbines, in your paper of 5th 1

ind shall feel obliged by their inwrtion in your nest pub-
iation. *

I " In regard to the angle formed by the extremity of the vanrn,
( buckets, with a tangeut to the circumference of the wheel, you
i tliat, in outward flow wheels, an angle of 30 deg. is
Ibpted, and that one author prescribes 10 deg. ; and yon add
I, in Tliomaon'a ijiward-ilow wheel, the corresponding angle is

1 30 deg. to 45 deg., and that, conaequently, a considerable

part of the power ia lost

" In reply to this we may state that the masinmni angle which
ocelli's in Professor Thomson's wheel, constructed according to the '
I'onnul^ prepared by him, is less than 30 deg., and that in large
wheels it will be little above 30 deg. ; certaiiJy the average does
not exceed 25 deg. But you omit altogether a very important
consideration, which materially affects tlie amount of work carrieil
away in the water leaving the wheels, namely, that iu the vortex
the water and wheel, at the point of dischai^e, are moving with
velocities greatly below those which they have in the outwanl ]
low turbine. It is the exeeasivoly rapid motion of the wheel at I
' 3 discharging en<ls of the vanes, or buckets, in oiitwanl-flow '!
irbines, that renders a very small angle necessary or advisable
n onJer that the vniter a»y be abtAfaKk i^jiiBtl'j «sai]^ i

asH ESfllNEEEING FACTS. [Div. V.

witliput the communiciLtiijU of a very prejudicially great radial
velocity to thu water on ita leaving the vanes. But, oa the con-
trary, in the vnrtex, the wheel has so little rotatory velocity Hb
the inuer, or discharging, enda of the vqdcs, that the water doe
not require to be shot backwarda rapidly ; and while the radiftk
component of its motion relatively to the wiieel is small, the pro
par tangential cornpnnent ia also small, and thus a larger anglfl
for the inner ends uf the vanes is perfectly admisaibte and pruper^
There wonUl be no riifficulty in diminishing the angle
tex, if that adopted were not as perfectly good as could he desired^'
To midce it smaller we would only require to increase somewhat
the depth of the wheel at the inner ends of the vanee.

"The following la an example, in the simplest furm, of the el
of this difference in the velocities at the points of dischar^go in tl
two wheels. The velocity of the outer cireumference of t)
Founieyron turbine, where the water leaves the ends of the v
may be fairly taken for this comparison as equal to that due tl
the whole fall, while the like velocity in the vortex will be thB
due to one-eighth of the fall (since the inner circumference when
tlie water leaves, in the hitter, revolves only at half the speed 01
the outer circumference, which, again, has the velocity due to
lialf the fall). Practically the actual working velocities v
he arranged somewhat less to allow for the practical effects of i&.
si^itances of friction, &c. ; hut as the modification would he aji-
phed to both wheels, it is unnecessary to take it into account h'

"If^ then, we suppose an outward-flow turbine in a fall of 20 ft^
and that its outer circumference is running with the v

mentioned = V 2 x 32*2 x 20 = 35'8" ft per second, a
that the angle formed by the ends of the vanes with the taiigeafl
to the outer circumference he the extremely small t^ne of 10'
deg. ; also that the water is sent backwanls, si) that the tan-
gential component of its motion (relatively to the wheel) b«
exactly equal to the velocity with which the wheel moves forWahli
(theoretically the condition of maximum eifect), then the abaolnbi
velocity of the water will he V tin. a = 35'87 x tan. 10 deg. a
6325 ft. per second, and the loss of head corresponding thereto =

^^^ - = 0-621 a With the vortex, the velocity forward of thl

\ wJiue! and backnanlof tlie vtatot ViWtaft yftW-uMi*

s.] FORMcr^E FOR TritDISES.

t' («r second, aad with the average angle of 25 deg., the velocity
. ;,iiiied by tlie water = 12(58 x tan. 25 deg. = 6912 ft. per
-ond, anil the lo^ of head coiTespoiiding = (i5i2 ft. Ttiue,
iking the tuiusnaUy small angle in the outward llow wheel, un<i
ihti average une actually used in the vortex, the amount of work
luri'ied away in the water leaving the latter is lesa than In thu
tipiuier. Besides wliich, we have, in tlie Tortex, the mivanU'ij,'C'
'i! a Wtter formed orifice.

"Turning to Profeijsor fiankiue's work on Prime Movers, and
.Implying his formulte for turbines to the supposed case, we lind
llie results to differ only very slightly from those wliich wu have
• liown. Professor Bankine gives, in the above work, a tahle of
i^'Ies which may be used for various turbines with corresponding
i[r-et ; for the outward flow wheels the two luwcst lie inentionB
111.- 14 j dttg. and ISj^ deg., and the angles he assigns for the vor-
tex, with the same loss in the final velocities, are 36 deg. and 43
de«(. respectively.

"In regawl to the paragi'nph you qnute (which is, Ihougli uot
qujto accumtely cojiied, fiom a nptice hy William Thomson, Pro-
fessor of Katural Philosophy in the Univereity of Glasgow, and
not the inventor of the vortex) we eannot see that it presents
nny difbeulty. It points out the important fact that, in the tor-
liinea of Fouj'neyron and Ponaelet, the water has communicated
|i> it a much higher velocity than in the vortex, where the maxi-
mum ia appmximately that due to half the fall ; whereas, in the
Fourneyroii wheel, it necessaiily attains the velocity due npproxj-
luately to the whole fall, usefully applied, and tn many exaniplos
'if reaction-wheels nmch higher velocities are imparted to it.
As the loijses from friction, &a., increase as the sqtiare of the
velocity, a reduction such as ia effected in the vortex id of great
importance.

■' We will now refer briefly to the question of the efficiency ob-
tained with the outward flow wheel, and we give the following
ipiotations from Weiebach and Biililmai:), who have prohalily
more completely examined the principles of the turhine than any
tilher writers on the subject.

"Weisbach writes ;—' These recipients of water power are in
many respects admirable machines; but to suppose that an efti-
•:int*i!ff = 85 to OSO haa been obtuued £i^m ^um, &'»»:». ^\'»'%k

r

I

»

gume mistake.' After finumeratiDg tim v^irious lusaes Iram fris
tiun, &c., whicli he estimates together to aiiiDivil ti^ 2i pen cent.)
lie proceeds: — 'TLere remain only 76 per cent, of useful effect
mill therefore a turbine that gives an efficiency uf 0'7S tuay fc
considered as a very excellent one, Tbe experimeuts of Moriiii
and other impartial persons, j;ive results aa to efficiency a
as 075, but never alwive this.'

"Biihlniaii wnt«s : — 'It is now fully admitted thut Fournev-
niQ deceived himself ia supposing that these vheels economiKd
80 per cent,, and more of the total available force. But thv
latttst and fullest experience has shown tljiit they eco
tainlj from 60 to 70 per cent., whi!ii those precautions ai'B ti
which should be attended to in their formation.'

"Do LacoIoDge cousiders that, as leaving a mai^in. for d
oration in the turbiue after working some time, 66 per cent n
be prudently taken, ' notwithstanding,' iis he says, '
presented by some lightly made experiments showing figures 6
079, 0'80, and even more, and the a-ssui-oncea of some inventon
possessed of more imugiiiation than information.'

" We might multiply such instances of the opinion of th'w
liest informed on the subject; but instead of this wu will gi?i
the results obtained by various experimenters on the CoDtinftn^
including Eedteubacher, Morin, Bieu, Daugny, and others. ~"
elfieieneies for fifteen different wheels (the majority mod
J'ourneyroa himself) are the following: — One gives lesa t
0'6; seven between 0-64 and 0'70; five between 0-70 w
075 ; OEB 077 j and one 079. The correotuess uf the last a,
pears to have been afterwards found to be doubtful by S
who made the experiment. All these are given as maxiiuui
I'esults, and the average for the tit'tei;n turbines is 0699.

" Of experiment)* made in America there are published j
detail, we believe, only those by Mr. Francis, at Lowell, sn
those by the engineer of the Fninnourit Waterworks, Philadiil'
pbia. Of the former we may say that, from the apparent e
and completeness witli which they were carried out^ it ia p
bable that their results are not far from the trutli. But they dq
not give an efficiency greatly exceeding the approximate calculi
tion of'Weisbach, although the wheel tested was of very laif
size, new*, of good workmaiiehi^, tuid inauiuderate tuil, aJul v '

TrMtires.] WOKEISO OF tPBTOITlB. 2W

Its best speed expu-tmentiiltj aecertaiueil ; in fact, witii vve^)'
condition in its favour. Yet tbe uioxinium eEReiency obtained
is 0'79375 ; and, by the way, there are in the same book experi-
Dienta exactly ainiilarly cuuducted on an inward flow wheel,
which gives a slightly higher result, Daiiieiy, 0'79753. Thus
Hit- highest efficiency rfiown by Mr. Francis is obtained froni an
: i . ivord-flow wheel, which, we mny add, is demonstnilily inferior
!■■ the vortex.

" Aa to the Faimiount esperiments, the apparatus enipKijed
ftir ascertaining the fall, the quantity of wator used, and t\m
iv.jrk done, are not such as to give trustworthy results, especially
in the short time allotted to each trial. Each cxperiiueat lasts
fnim twenty to tiiirty eeconds, during which a weight is raised
to a height of 35 ft. j on the cord which hfta the weight are tied
two pieces of tape, 35 ft. apart, and au otiaerver notes the time
at which the first passes a given point (the turbine liaving pre-
viously attained its proper speeil), signals to an asai^taut to direct
the water from the turbine into a measuring trough, and when
the second tape passes, again signals for the water to Iv stopped,
iiotea the time, and tbe experiment is complete. An errur of
one second in the time of admission to, or stopple of, the water
from the trough will alone malce a difference of 4 to 5 per cent.
in the result. Although the most important errors do nut neces-
sarily appear in the recorded rei-idts, yet even in these, the almost
constant variations of the quantity of water used, and of the
time occupied, in repetitions of experiments, where tliey should
be identical (because the weight raised, the height of liil, and the
fall pf water on the wheel are given as unaltered throughout),
abundantly prove the existence of error. Certainly these ex-
[•eriments cannot be held as authoritative against the unanimous
leatimoiiy of the numerous eminent scientific men who have, in
Europe, investigated the tfuestion of efficiency by rigid trials, and
also by the application of the general principles of hydraulic
science."

In answer to the foregoing letter, the following appears in the
' Enyineer:' —

"A letter appears in another cotunin in defence of the so-
c«Ued ' vortex whceL' The writers touch upon several points
ri'iiuiring a few woiiis from ouwelves, and these joints we will

i

EKCIKEERING FArrs.

[Div. V.

I take ti]! ill tlie ordt^r in wliiub wb liiid tliem. TLe tmgle of tlie
I inner ends of tlie buckets in the so-called ' vortsx wheel,' is g
I by Mr. Fairbaim, in bis wurk on 'Millaand Millwork,' page 164,
k Sit from 30 deg. to 45 deg. (Mr. Fairbaini spt^aks of Profeasur
I James Tbomson, tbe, patentee of tbe wheel in question, as '<
I of ray own pupils,' in erroneouslj' giving him credit for tlie in-
I vuntinn of ' turbines in which the wuter fluwa horizoiitally in-
I warda.') It is our inipresaion that the angles mentioned were
I ^ven in a paper upon this wheel once read liy Professor Ttom-
I son himself. If he now adopts an angle of 25 deg. from ft
I tangent at the extremity of tbe buckets, we must suppose that ]it
I i* giving less of the objectionable reyersed curvature to the
I buckets than be formerly did, Lir possibly he makes the circle of
I the inner extremities of the buckets greater than oue-hulf of tb«

■ ■■whole diameter of the wliee!. In either case, or in both, the
1,'jmrtial return to the practice of former makers of inweid-

■ 'fluw turbines must, we should say, have been attended with ad'
I Vantage.

I "We are next told that 'the velucity of tbe outer circomfer-
I c&ce of tbe Fourneyren turbine, where the water leaves the ends
I of the vanes, may be fairly taken, for this comparison, as equoi'
I ti> that due to the whole fall' We cannot answer for everything
I that M. Fourneyron may have done, but in no good outwatd-
I flow turbines with which we are acquainted is the velocity of the
■'Outer circumference equal to that due to the whole fall, or i
I tiling near the wliole fall. In outward-flow wheels giving from
I 78 to 79 per cent, of the full theoretical effect due to the vator,
Ltlio velocity of the inner circumference has ranged from 64^ pec
I cent, to 67 per cent., and tbe velocity of the outer circumferenCB
I from 68 per cent, to 83 per cent of that due to the whole fUL
I In other words, the velocity of the outer circumference ranged
I from that due to 46 per cent, of the "full up to that due to 6"
I per cent of the fall ; 46 per cent of the whole fall generating
I 68 percent, of tbe velocity due to tlie whole fall, while 69 peg
I cent of the whole fall would generate 83 per cent of the velodtjr
I due to the whole fall. The relative velocities of the disdiaig--
I ing ends of the buckets are made use of^ by our corrospoudetits,
I to show that the inward-flow wheel may have a more otatuM
Lt;y,'ie,. hetH'eeu the enda ofthe'buGV.tten.wAUw^'iiUt'j tlififti

tl-kbisbs.] working of turbines. Sll

than outward-flow wheels. They do not mention, however, that
the Inward-flonr muni, other things being the same^ have a mora
ohtuse angle for the buckeU than an oulward-flow, in order to
prriperly get rid of the water,* and to prevent ita being forced
into a direction nearly opposite to, instead of at right angles to,
that ill which it entered the wheel. Thia wovid, indeed, be a
llitw of the water ' backwards,' sa our correspucdenta use the
iBmi, whereas, in their wheel, the water should only flow for-
wards and towards the centre, and were the buckets eontinued
to the centre (if we may for an instant suppose such a. thing),
the inner ends of the buckets would require to be radial to the
wbecL More strictly, as the inner ends of the buckets approach
the centre of the wheel, so must they, pi-o tanto, assume the di-
rection of ladii to the wheel. All this, however, has nothing to
^Mki with the &ct, that whatever centrifugal force is left in the
^HBuent water is exerted against the head acting on the inward-
^IpDW wheel, and in favonr of the head actmg on the outward-
^Blow wheel This is the main point wlilcli we have all along
■ iiiged against inward-flow wheels,

" Heit as to the unintelligible, or, if intelligible, incorrect state-
ment of Professor WQliam Thomson, as ijuoted by Mr. Mallet,
Hind again by ourselves in an article on turbines in our impres--
^HBOn c^ December 5th. If the statement means what our corrc-
^l^ndente state that it does, it is untrue, because, let, in well
^■Iratstructed outward-flow wheels the velocity with whii:h the
water moves in the buckets is less than that theoretically due to
one half of the fell — that is to say, less than 70'7 per cent, of
the velocity due to the whole fall. A velocity of 62 of that
due to the whole fall, oorreeponding to 38j per cent, of the
whole fall, is a common velocity for the passage of water through
the narrowest parts of the buckets of good outward-flow wheels.
Slid, Whatever may be thia velocity in outward-flow wheel?,
there is nothing whatever in the principle of construction of in-
ward-flow wheels, as a class, which can necessarily cause the
velocity of the water through the buckets to differ from that in
^^Otward-flow wheels. Professors William and James Thomson
^^HtTB shown a want of knowledge in contending for any such
^^■fferencQ. In respect, therefore, of the friction of the water in

' B43 ENGINEERING FACTS. [Div. T.

the buckets, tliere is no necessary difference between the outwarJ-
flow and inward-£low wheels.

" Our correspondents then quote a number of authoritiijs to
show that no turbines can give oftmore than 76 or 76 per cent.
of the power of the water, Tliis limit is one deduced from
theory, while a«thoritiea entitled to greater confidence SBsign fl
per cent as a result actually atbtlned in practice. Our corro-
apondents admit that Mr. J. 13. Francis' statements are probably
'not far from the truth.' And, in almost the ne;ct sentence,
they commit a flagrant error, in representing the highest efficiency
reported by Mr. Francis as '79753, and as having been obtained
from att inward-flow wheeL Mr. Francis had stated that two
out of three outward-flow wheels, of 190 horse-power each, had
lean most carefully tested at the cotton mills of the Appleton
Manu&cturing Company at Lowell, that the data were put into
his hands for computation, and that he found that 'the mean
maximum effective power of the two turbines tested was eighty-

r eight per cent, of the power of the water expended.' We mi^t
employ a harah term to designate the manner in wbich our co^
respondents have made use of Mr. Francis' work. He had, it h

, true, himself designed four outward -flow turbines of 165 horse-
power each, and the highest result obtained from the only o
these tested was -79375. and he had also designed two inwanl-
flow wheels of 230 horse-power each, having the great external
diameter of 9 ft, 4 in. (S ft. internal diameter) and one of theae
once gave 79753 efficiency. The 40 buckets of these wheels
made the sharp angle of 1 1 deg. with a tangent to tiie ii
cumference. These wheels were made with great accuracy, and
■were probably the most complete and moat nearly perfect inward-
flow wheels ever made, whereas Mr. Francis' outward-flow wheels,
made for the Treniont and Suffolfe Mills, were not fitted with
the 'diffuser,' invented by Mr. Boyden, and applied by bin
the purpose of utilising the enei^y of motion in the water on
leaving the wheel The large turbines of the Appleton, Merri-
mack, and some other cotton mills at Lowell, have these diifusets,
and are known to utilise &om 80 to 85 per cent of the eflicitmcy
of the water,

"All that has been said in favour of the inward-flow vheel
dues not remove the facts, \A, &b,\i nun^ tn \<a» ouitrifbgalj

&] VORTEX AND PABALLEL rLOW TURBISE

^'foroe is carried away in tlie water issuing hom all lurbinea, anU
2nil, tbat this lurce acts antagonistic to the water doing ite work
in the inward-fiow wheel, aad in favour of the water (loiiig its
work in an outward-flow wheei Upon this very point Professor
J. Thomaon 'ataked' (and, it can hardly be denied, lost) his 'pni-
fessional reputetion' in our own columns last summer. A liki-
want of knowledge has led to the absurd steteut^nt as to the

tlocit; of the water being leas in the buckets of the JDWard-
w than in those of the outward-flow wheel If the velocity
the water were really less in one wheel than in the other
would only follow that leas water was passed and leas work
ue. The standard of comparison between aiiy two turbine:
let of course be the quantity of water passed in a given tiint^
a given iall, and if these be the same, and the area through
i narrowest paits of the buckets be the same in both wheels,
' the water must have the same velocity, and its motion be at-
tended with the same amount of friction in both turbines,
whatever may be the principle on which they may be (
racted. The best tuvbinea of all classes move, with relatioii
> the water passing through them, with a. velocity equal to
ut theoretically due, not to one-half, but to about three-eighths
f the fill], and often, indeed, with both outward and inwanl-

V wheels, with the velocity due to but 31 per cent, of the fall.
1 inward-flow wheel must, in order to pass a given quantity o

a given fall, be of larger diameter than an outward-

V wheel, and as the guides, in the liist-nanK^d wheel, i
1, the weight and cost of fltting will be greater for '

I^Brd-flow wheel The ao-called 'vortex wheel' differs from other
Biward-flow wheels chiefly in having but four guides, atid buckets
of needless length, and having a reversed curvature wanting
correspondence with the path of the water through the wheel, and
the 'vortes,' or any other inward-flow wheel, if made for the
same quantity of water, the same foil, and the same number u
revolutions, and of the same materials, will be found to cost
considerably more than the outward-flow wheeL

" But for general purposes we believe the parallel flow t
Jonvol wheel to be preferable to either the outward or inward-
flow wheei Our reasons are, chiefly, that while the action of the
water is scarcely leas effective than in the rourneyron wheei, the

f

2*4 ENGIKEEKING FACTS. [Dnr. Tl.

Joaval wliGel may, with tLe uid of tlie 'ilraft bus,' or suction
pipe, be placed above the tail water ; autl if the fall be
25 ft. the wheel may ha placed even 25 ft above the tail race,
and thus, while obtaining the same effect oa if the wheel v
subnie:^ed, it ma; at any time be left high and dry fur repain
by aimply turning off the water. Thus, with a few feet of p'
ing a Jonval wlieel giving from 75 to 80 per cent, of effect may
be more cheaply put up than the cheapest water motor of any
other deacription. Our correspondent eeeka to throw doubt npoii
tba experiments made by the Philadelphia Water Department,
and yet of nine trials made with one form of Jonval wheel, witJi
thu gate fully open, but witii loads varying in nearly all the
trials, the variation in efficiency was but from 7771 to ■8310,
the tjuantity of water used in each experiment having been actu-
ally measured, and not estimated by a formula. "With another
form of Jonval wheel, the trials having been made under pre-
cisely the same circumstancee, the variation in twenty trials, dur-
ing which the gate was fully open, was but from 7857 to ■8777,
the average being '8485. These differences were fully aggounttid
the difierenoes in the weights lifted ; the load on the wheel,
with the lowest efficiency, having been nearly 20 per cent, greater
than in the trial giving 8777, or 87J pei cent., which wai
elusive of the friction of the wheel and testing apparatus. The
Philadelphia experiments sliowed, on the whole, u remarkable
correspondence and probable accuracy ; and we have
'no hesitation in saying that Jonval wheels may be constructed
to give off 85 per cent of the full theoretioal effect of the watet
expended,"

DIVISION SIXTH.

RAILWAYS.

The most novel application of railways of late to large towiu
" een in the introduction of underground lines. The !AIetn>-
lohtait Underground Kailway in London has been a complete
iuccess, both in an engineering and commercial respect, so maeh
H tlmt several otliers ate ptoYiosBii, audi, ase WEmn I'aj"

fiiiLWATs.1 WOUKING OF UNDEIiGKOUSD RAILWAYS. 116

present. These, however, are likely to lueel witli strong opptisi-
tion from the Metropolitan Board of Works, coming in coniact,
as they lio most aericmfily, with their extensive drainage opera-
tions. The only reinainiug difficulty in uiideiBround railways,
not quite solved, is the application at Incntuotive power without
uccasiontng the production of noxiouB giisep from the furnace of
the lK>iler. At present, when the engine enters the closed tun-
nel the exhaust steam is turned into the tender, and there con-
densed, but there still issues from the month of the funnel much
sulphurous acid and other disi^reenble products. It has been
proposed to work these engines by atmospheric pressure ; this, no
doubt, would be very gocjd, so far as securing efficient rentiJation
from the exhaust vent, but the power realized from compressed
air is not more than 60 per cent, of the power required to com-
press it, besides the objectionable heat generated hy compressing air.
The writer has had occasion to design some heavy air-eompressing
engines to compress air to 50 lbs. per sq. inch, and he found, in
working theair cylinder at a rate as slow as BO to lOOfe^jt of piston
per minute that the temperature of cwnipreaBed air, altlmugh the
cyhndcr was aurroun<ied with water, rose very shortly to close
npon 300° Fahr., and in nsing this air in this particular case not
mote than 40 per cent, of the original power was realized. Mr,
Fowler, we believe, has made some experiments upon hot water
locomotives, that is, water contained in a reservoir at 400° or
thereabout, hut as yet the mutter has not been fully developed.
Another and perhaps a more feasible plan is proposed by Messrs.
R. and N. Hawthorn, the eminent locomotive engineers of New-
castle. A contmunication on this subject was made to the
members of the British Association, of which the following is an
abstract : —

"A system of working railways by fixed engines and topes
has long been in use on the colliery railways around Newcastle-
upon-Tyne, as well as in other districts, and a plan for the same
was made the subject of a patent by "Mi. Benjamin Thompson,
then of Ayton Cottage, in the county of Durham, and was intro-
duced on one or two colliery railways. It consisted of a suceeaaion
{ fixed engines at certain intervals from one end of the line to
)r, each engine being employed to work a, portion of the
|iiwB;f iu tiie foJIoH-iug

r

I

I

•M ENGINEERING PACTS. [Dit, VI.

" The engine gave motion, to two rope rolls, and the rope from
one of those rolls was attached to one end, aad the rope from
the other roll waa attached to the other end of the tcain. While
one of the rope rulk waa disengaged from the engine, and
allowed to run looae, the other was in gear, and the rope from tt
waa passed along the line, and round a loop sheave, then brought
back and attached to the traia The engine being put ii
tion the train was dragged to the furthest end of the section
worked by that engine, at the same time unwinding the rope
fnim the loose roll, and taking it with it to be afterwards e
'ployed to drag back the returning train. This waa continued
throughout the line, each successive engine taking up the train,
and carrying it over a section of the line. This method t
a satiatactorj one for the convejance of passengers, as the rider
or guide in charge had not sufficient control over the movemeata
of the train, and there is an objection to the carriages being at-
tached directly to the rope, and at such a distance from the
tive power. Ropes have been, and are yet, applied in other
waye, for instance, on gi'avitating oi descending planes, down
which a loaded train passes, having the rope attached to the
after end, round a sheave at the top of the incline, and then
down to the ascending train, and thus the descending loaded
train draws up the ascending light train ; or, where the load has
to ascend, a fixed engine is employed to draw it up, and the de-
scending train takes the rope down with it. Ropes are also ap-
plied in a variety of ways to the working of incUnod planes on
passenger railways. Thus there is nothing new in the use of
stationary engines and rnpes for working railway traffic. It will
be observed that, in all the cases referred to, the rope is attached
directly to the carriages.

"la the proposed plan now offered to the notice of membera
of the association the means of communicating motion to the
train gives greater security, as well as the advantage of avoiding
the necessity of attaching a train to the end of a rope, thus en-
suring to the guard as complete control over the movements of
the train as he now has in the employment of the locomotive
engine. In the new system, it may be stated without exaggemtiont
"lat the rope drives the locomotive wheels, and each Cftrriage
irries its oivn railway.

riiWATO.] WOBKING or DNDEEGROCND KAILWATS.
" It is propfised, with the onlinaiy construction and gangc of
railway, to place in the intermediate space between a douWe
line of rails a series of double grooved theaves, fixed in Bpiiidlus
or axlea which paes across under the rails, extending a little
over the centre of each line ; a plain wheel or roller is fixed
upon each end of the^e axles, by which the motion is commuui-
cutdd to the train from a stationary engine or engines, placed at
a convenient point ot tlie line — by means of au entiles wiil-
or rope, passing alternately over and under the grooved aheaves
to the extremity of a section of the line where it is taken round
a large loop sheave, and returned to the engine, now passing
over each sheave which it before passed niider, and viai ver»ii,
tlie double groove providing for the rope crossing itself without
cuntncL ^

" Having traversed twice along the line of alieaves the rope
goes ^ain on to the ^uge winding sheave of the engine, on
which a sufficient number of turns are taken to ensure the re-
quisite friction.

" From this ajrangemeut of the rope on the sheaves it will be
seen that every alternate sheave i-uns in the same direction, and
every intermediate sheave in the contrary direction ; and this
motion is communicated to the traction wheels or rollers before
muutioned.

" It is proposed to construct the carriages for passenger lines
on the principle of those used in America and on the Canadian
railways, of a length of from 60 ft, to 7fi ft,, and supported on
bogies, and capable of seating from 120 to 160 passengeiB, each
carriage to be fitted with traction bars — these bars extending
over two or more alternate traction rolleis — and to be furnished
with the ordinary flanged wheels, for running on the ruil& The
traction bars, of which there are two, ore [ilaced side by side, at
auch a distance from each other as may be necessary to meet the
requirements of the line; and these traction bars are worked
either in connection with, or independent o^ each other by a
suitable arrangement of levers or other gearing, by which eitlier
of the hara can he raised or depressed, thereby bringing a por-
1 of the weiglit of thf carriages upon the traction wheels or
pollers, thus giving motion to the train of carriages in either di-
Ectioa Or both these bars can be raised out of contact with

ENGINEEHING FACTS,

[Dfv. Vi

I

traction wlietsls or rollets, and the traia left ii-ee from all
tractive force.

"The traction bars will be nearly tbe full length of the
carriage, and the traction rollers vrill be placed about 18 ft.
apart, or at the" rate of 293 per mile.

" The carnage made in this way is adapted for running with
either end first, being pro^-ided at each end with a platform,
which the driver stands to work the traction bare ; and it is o
eiilered that, for ordinary traffic, one carriage will be sufficient to

a train, but two or more may he attached to each other,
the number of trains of a single carriage each may he increased
to meet the requirements of the tralEc.

Tbe motion of the train can be qnickly and cartainlj re-
tarded or stopped by raising one bar and depressing the otlier.
ill the manner of a brake, thereby reversing the direction of tbo
driving motion.

" A separate or independent traction carriage may be used,
fitted with the traction bars and gear; but it is considereil that
such an arrangement would, in most cases, only be adding u

ess and unnecessary weight to tie useful portion of the train.

Xhe present line of undjerground railway through London,

1 Paddington to Farringdon-street, is favourable to the use of
the locomotive engine, where so much of the surface of the
ground under which it passes is unoccupied by buildinga, and
readily admits of a good deal of open cutting and ventilation at
the stations, which cannot he the case where the railway passes
under the densely-populated parts of a city, as those projected
London must do. In such cases it will be necessary to provide
for working in a continuous tunnel of, perhaps, three or four
miles in length, in which the steam and smoke of loconiotLv<
engines would prove obnoxious to a much greater extent than ia
experienced on the present line, wliich is only partially an under-
ground railway. As there does not ap])ear to he any means of

idying tliese evils, except at a very extravagant cost, it is be-
lieved that t!ie new system may be introduced with advant^B
'n Buoh cases as are above referred to, viz., railways passing under
arge towns, or in situations where opportunities do not occur of
laving openings to the surface.

TJje iuainteiinrioe of the eu^iuea w\U bo winaiderably l(%

k _

w

■S.] LIGHTING OF RAILWAY CARRIAGES.

lan with locomotives, to balance the expense of keeping in
■working order the sheavea, ropes, &c, which will cost more than
an ordinary line.

" lioth caluulation and experiment on the adhesion reqiuied tu
propel a train remove any reasonable doubt of lieing able, )<y the
new system, to olitain sufficient tractive force by the tractive
'bars and rollers, and it is evidently ijuitt feasible to increase this
tractive force if required.

" With a locomotive a train of fifteen or twenty carriages has
to be drewn by an intense pressure on six or eight points, and it
is this which adds such a heavy item to the cost of railway
maintenance. This disadvantage will be, to a great extejit, remedied
by the proposeil system, the tractive force being more disturbed,
and conaeqaently, the wear and tear diminished. Finally, if
snch a system as the one proposed eon be introduced free from
the objections that have hitherto been considered inseparable
I'rom the nse of ropes, it will greatly facilitate the construction
and extension of undetground railways without their present
draw- backs."

The carriages of the uiidergronnd railway are beautifully illu-
minated with gas supplied &^m reieivera over-head, contjiiniijg
gaa at a very high pressure. On this subject a corresfwndeiil
of the ' Pnietical Meckama' Journal ' makes the following sug-
gestions as to the various points to be observed in lighting trains
with gosL — ,

" The pioneers in this country, in the construction of apparatus
for compressing gas, and using it in a portable form, were, Thel-
luson, Gordon, and Heard ; and more recently in Fraiice, a
system has been adopted of supplying rich portable gas, which
has extended itself to several important towns on the Continent,
and with a very fair amount of success. There are companies
estahliahed at Paris, Milan, Turin, and Moscow, their object
being chiefly to supply gas to those parts not within the range
of the ordinary gas companies' mains, so that they do not act
antagonistically to them. M. Hugon, of Paris, is more or less at
the head of each of them, he being the gentleman whose mode
~ production, compressitm, and regulation of the gas, has been
In America, the steamboats and some of the rail-
tiains ara lis^ited with gas made on the boat or train, as

r
I

aso ENGINEERING FACTS. [D:v.

well also as by tbe means which have ao fretiuently been tried
in this country.

"Thompson and one or two others have be«n tolerably ai
CHBsfiil in the lighting of railway trains, bat it may be preeiuned
that thoir systems have mnuy objections, or railway compatitea
would assuredly adopt some such plana of lighting their carriage^
which for many aelfevideut reasons are preferable to oil
the Society of Arts, Mr. Teiilon, representing the railway interest
clearly showed that while he was thoroughly acquainted wltb
what had already been done, yet that the result, ao far, was any
thing but satisfactory, at least not so much so as tg warrant thft
Gonipaniea adopting it generally.

" I am aware that the gas, as deliyered at the housee of cw
tomere at Paris, which is stored in reservoirs at five atmosphen
pressure, is readily regulated from that pressure down to thai
which is necessary for being properly burnt — say equal to i
column of water live or sis-tenths of an inch in height, but thtj
means by which that is accomplished there, cannot be i
HvaiLible for Hghting railway trains with gas.

" I venture to say that there are considerable difficulties fc
overcome before a proper system of lighting railway carriage^ ai
we now find them, and for long distanceii, can be success&llj
brought into use,

"The conditions which railway companies must have are;—

" 1, That but little room be taken up by the apparatus.

" 2. That the M^plicatinn be readily made to existing carriag
at Utile cost.

" 3. That the hght be butter, and at less coat, taking evei
thing into consideration, than lighting by oil.

" 4. That the apparatus be simple, and that each carriage be
lighted independently of the others, so that they may be detached
at pleasure, without putting the light out

" 5. That the light last as long as the oil lamps, or say f
London to York, Holyhead, Exeter, or Dover.

" 6. That it be as certain in its action, under all circum-l
stances, and that defects be as readily corrected as by the pra-l
sent mode of lighting.

" The plan adopted at the Metropolitan is not generally apj
eahle, and only fur such an except,laaaL Ua^ of cailwfty a

^^r, toi

1.] LIGHTING OF CARRIAGES.

e gaa at thfl mpre pressure of that which is necessarj' f"r
liiimiug it, would require fnr the joumeiy between Loodou and
York, hiilf ns much cubical capacity as the earringcB themselves.

" In OTiler to faliil the conditious I have naiueil, the gas must
bp condensed to ten or fifteen aliuosphereg, and the difficulty is
I'l rediiee tiiat pressure donii to five-tenths of an inch column of
water, and to maintain it at suab under all ciicnniBtancea, so as
tu comply with the conditions I have stated, and the regulator
must be entirely metallic. I am fully acquainted with all the
pnbliehed methods from the first introduction of gas-lighting,
but not any of them comply fully with what railway companies
must and will have, before they generally adopt the principle of
lighting railway trains with gaa"

In India a most stupendous railway undertaking has been
lately brought successfully to a close. In it there occurs an in-
Inline of unusual length and eteepnesfl; its length being over 15
miles long and averaging 1 in 48. An excellent description
iif this incline called the " Shore Gliaut " was given in a paper
rend at tlie Mecliauics' Institution, Bombay, by the President,
James J. Berkley, Esq., M. ICE., F.G.S.^Chief resident En-
ilineer of the Great Indian Peninsular Eailway. The following
is an abstract: —

"What the circulation of the blood is to the individual, a
i;omplete and spci'ily Cfliamunication is to the body politic ;
• tisease and dcatli result from a stagnation of the cui'rent of
life, while genera! poverty and local faming are contuiually
(.resent in a country unprovided with easy locomotion between
its outiying districts. Good communication equalizes the prices
of tlie necessaries and luxuries of life by adjusting and concen-
trating the markets; it brings the right product to the right
place for its consumption, and it assimilates all the classes of a
nation through facilitated intercourse and a general diffusion of
comforts and luxuries. In time of war, the advantages of good
roads are increased tenfold, multiplying by ^peed the momentum
of the body of men chosen to repel an invader. The Romans —
conquerors by profession and herita^'e — always consolidated their
freshly acquired territories by sound and durable roads, many
of wbich are still extant aa ineffaceable monuments to Roman
SoKBight ami /loirer. England — Roiub'b \:\e\» ^^^ tokwj \.\\\\\^Ji —

ENGINEERING FACTS, [Div. V[.

r

^H has always been noted fur giKid comiuUiucationaj and ]i)Tig befon

^B Englidhiiien ran the first louomotive on. a line of raik, they h

^V einpluyed for years postal acrangementd on macadamized r

^B peculiar to the country and unsurpaaaeil for speed and efficiency.

^M It is strange that the same nation should hare eo t _

^1 crdstinated with the introdnetion of improved means of tronaii

^H into their immense territorial poBseasions in Hindustan ; that thi

^B palanquin, with its dusky human liearers pursuing their toilsomft

^B march under a burning sun, shovdd only have been replaoei{

^B within the last few years by carriages impelled by xteam aloiijf

^P iron roads ; that the bunch of iron rings used by the native run*

ning courier to scare away the byienas uf the jungle, sbonld have

been but so lately superseded by the shrill shriek of the lucomotivi

steam whistle.

" In a recent work it is stated that the cost of locomotion ill
India is such that, during the campaign in the Puujaub, e
man in the British army bad cost £150 in transport alone; th(
usnal allowance on an Indian line of mareli being one camel b
lira fighting men. AUbougli the imporliancii uf easy means o
transport of troops from one point of India to another was loiij
acknowledged, and although it was generally known that Indi^-
with cheap raeana of transport could ' clothe the world in cheaj
cotton,' it has required the united stimuli of a wide-spread mili'
tary mntiity on the one hand, and of a complete stoppage of 01
ordinary supply of cotton on the other, to overcumo the obsloclet
in the way of a g^d inland communication for our East Indian
poaaesaiona. At last, however, the first meshes of the i]
destined to rajver the land of the burning sun are at lost being
laiii down; anil English science is now affording some compeu-
sation to a people snbjngated by Englisli lust < ~
dominion.

" A line of mountains called the Western Ghauta run almotf

Pthe entiin length of the western coast of the Peninsula of Hill'
liostan. They extend in a nearly parallel lino — about 30 milei
distant from the coast — the whole extent of territory between
Travancore and Bombay. This abrupt and lofty volcanic »
has offered for countless ages a serious obstruction to tlie com
iijuniaition between the weatera ijorta and the interior of t'
iMuntry. Until laMv it tools, a i'lvi.'mei tA^-«ii4a.-siW%

s] RAILWAYS IN ISDIA.

itid three fur goods, to traverse about 48 mile& of the
of the country. Along a range of 220 inil<« there were no hojies
at all for wheeled traffic; hut rimply a number of precipitous
foct-patha and steep rugged tracks for heasts of burden. The
eonstruction of the railway passages of the Thull and Bhure
Ghauts 'were thus imperatively necessary before India, and espe-
cially the port and I^eaidencj of Uombay, could enjoy the full
benefit of railway communication ; and the engineers of the Great
Indian Feninaular Railway may well congratulate ibeniselves on
their success ia oyercoming the enormous cUfficulties of this psr-
ticular portion of their line.

" The investigations of Mr. Berkley, the chief engineer, and
bis colleagues, on their anival at Bombay, in 1850, resulted in
the rejection of the Malsej Ghaut Railway ascent selected by the
late Mr. John Chapman, and laid out and surveyed by Messrs.
Clarke and Conybeare. The present Incline is a modification of
a second projected design laid out in 1852, hut embodying the
objectionable feature of a statioikary engine plane; fortunately,
thia has been avoided hy laying oul a continuous locomotive
gradient from the base to the summit of the incline. After some
delay, hi 1853, from the hesitation of Lord Dalhousie, caused by
t.he gigantic character of the present designs; and after some
iiiodifications during the progress of the works — scarcely to be
made clear without the aid of a map — the present Incline was
finished lost year.

"TlieBhore Ghaut Incline of the Great Indian Peninsular
Railway is 15 miles 68 chains long; the level of its base being
196 ft. above the sea, and its summit 2,027 ft.; the total eleva-
tion surmounted by the Incline in one long lift is 1,831 ft., and
its average gradient is thus 1 in 48. This extraordinary portion
of the railway system of Western India ia now successfully oom-
pleteil, after being in progress for seven years and a quarter ; and
on. tlie 30th of last March an experimental train was run for the
first time, accomplishing the 13^ miles from Fndiislicrre to Elian-
daila in 52 minutes.

" TTiere are only two other mountain ascents in the world that
can be somewhat compared in magnitude and difficulty with the
Bhore Ghaut Incline. The Giovi ascent of the Apennines, and
of the Semmering ascent of the Boric Alipi, taa. waKi^'j \fc « " "

r

I

I

251 ENOINEpEINQ FACTS. [Div

to equnl in difficulty thia port of the Great Indian Fuiiineulwr
Kailway.* The almost inaccessible volcanic scarps of the Bhor
Ghaut had to be encountered by cuttings of a most difGcnlfi
cbarocter; in some flituationa, one-half of the line ii
benching, while the other half had to he caiTied on a
bankment, or on an embankment supported by a wall of masoni^
In other places, it was imjMssible to use battering walla, and tha
line had to be curried on arches; while in some inBtaneea, one*
half of the width of the line stands npon rock benching, and the
other half upon vaulted arches; in fact, the great number of ox*
ti-aordiuary cross sections — nearly 2,000 — in probably unpanli
leled by any other engineering work. In the vicinity of tha
numerous beds of basalt, of intense harilnesa, intersected by the
inchne, great dilhculty was caused by some of the masses of rock
talhng away in large blocks as the cutting proceeded. One p
tion of the line shows a vertical face of 60 ft. to 70 ft. for a
a quarter of a mile. All the materials had to be hauled up a
great length of new roads, whose formation was necesaitated by

AKflnL imm Peycrbucli

aisiani^jj,^ Incline commenccB 7f milea from Gfnol^ at a point 886 ft,
Travanco. level of the Meilit«rraiiB(iu, ami lucsudu the Apemunea. Ili*
has offered l^'^'ine is replete with extensive and. extraorJinary worksi and
I _ _■ ,. _iry opeiitions and atuiiy occupied from 18J2 to laiS, a period

JWUniCatlOn .■!,i;„ „-^„^, ,„ «-«. IR.-i*. it. «,nst™,-tinn l,.vn»'t«t«<

intoy. ITii,

It was opened in Miy, 1SS4, i

»-l

RAILWAY W ISDrA.

Hlie dUiep and mnuntainous character of the Ghaute; ten miles
■i)f cart-road, more than twice that length of briille sud I'liUock-
Ipatb, tmd a mUway siding of ntwly two niilee. had to be laid
I tluwii in order to bring up the uateriBls. Tho two milPB and ■
I lialf of tunnelling have been cut into trap rock of great luinbiesa,
[ Aud the precipitous character of the liilLs rundered it iuipoBtiible
' to sink ahafte. The tunnels had to be entirely mined fruni both
ends; and the sharp curvea and steep gradients made this a
work of some nicety; while the euforoed absence of shnfts ren-
dered the ventilation of the headings exceedingly difficult. Thi-
arched of the three i^uartere of a mile of viaducts are built <if
squared stone laid in courses, with ashlar and quuiua. ^'<> bricks
were used in any of the works. Their fiiundationa were required
tu be exi:avated to a great depth before a sufficiently secure bed
of rock could be I'eached, Up to the surface of the ground the
viaducts were built of solid block -in- course masonry, and above
that of block-in -course face-work, tied Hnnly through, by bonds
tjf block -in-courcie, to the inside work of sound rubble.

"The engineering difBoultias we have slightly alluded to —
hard to surmount in any country — were doubly so under the
burning sun; the miasmatic exhalationa of tbe-Boil; the fbmild-
abte Ghaut monsoon; the drought of water; all specially char-
Kccteristic to that part of India. The railway works had to be
' 'most completely stop^ied during the four months each year of
tlie rainy season. In March, 1861, 43,000 men were employed
Q the works ; in the following June, this number had dwindled
1 to 4,000. The disadvantage of the annual dispur.ijd of
the skilled wotk-people was, however, in some degree overcome
by employing them in the Poona quarries in preparing the stones.
The scarcity of water during the hot weather was another great
difficulty; and the water for drinking purposes, anil for the
masonry, had to be brought up from the Oolassa Kiver — a dis-
tance of 4 tu 5 miles irom the centra and some of the lower part
of the incline — on bullocka 1,500 of these animals were con
stantly employed in the carriage of water when the works were
in full progress. In the season of 1859-60, the cholera cauaedi
a great mortality, and an almost complete dispersion of the work- J
people. The inferior labour of the natives, as compared
that of JEaropeajis, also deserves tq lie le.ga.iAftiNtVft'ft'v^^^.'eSM

EKGINEEKING FACTS. [Dit.

^V SSfl

^^f s compaiisou between the Bliote Gliaut locline and the two
^V eimilar works carried out in Europe,

^H " Oue of the most original features of this steep railway ii

^^ chne consists in the peculiar system of ' reveising stations,'

^H adapted to accomplish an inci'ease of the length of ttte base, and

^B a flattening of the gradients ; as also some reduction of the yerj

^P heavy works that would be otherwise required. It is an appli-

^ cation of the American ' zigzag ' plan of laying out a mounlaia

railway ascent. The line is forked into something like ths

shape of the letter Y; and the engines being turned at the e

tion, the tail of each traui becomes the head. It appears to ga

back aa it leaves the station; but the train continues its

journey by running up the other branch of the fork. Thia plan

permitted an alteration in the direction of the line at a veij

acute angle, by n)eau3 of points and crossings — avoiding the

otherwise necessaij' adoption of curves of an objectionably small

i-adiua.

" The rails of the permanent way were manufactured to a
apecial Bpecification, prepared by the then consulting engineer—'
the late George Stephenson. They weigh 85 Ihij. per yard, a
four-fifths of the. number are 21 ft, long, in order to lessen tlu

(amount of joints. The entire piles out of which the rails i
rolled, were built up with hammered iron. In order to protect
them from the heat and moisture of the long sea voy^e to India,
all the rails were dipped while hot into hot linseed oil — a pro-
cess which has been very eucoessful in also preserving the raik
under wear. The joints are fished, and they rest on small caat-
iron saddles, spiked to longitudinal timber bearers, the ends c

I which are secured to the tianeverse sleepers by means of fang'
bolts. All the ohairs were cast from iron subjected to a daily
test by the inspectors of the company — the rail-bearing Burface
being chilled,
" The engine rolling stock for working this incline consiata olj
seven pairs of double four-wheeled tank engines coupled back 6
back, or rather fire-box to fire-box, and running in pairs. Tlia
arrangement, while afibiding the requisite tractive power fbl
steep inclines, adapts itself very easily to sharp curves, and i
our opinion is infinitely superior to the monstrous Eugertli ei
I pi'o, BO affeetioned ou tiie CoiAvneTA. Kvniia.i ««'^ss& '<a

RiUtw«¥i;] lI'i'KW ^'WIWBB OB" BOtMRtJ STOCK. WT

tially used on the Giovi Incline of the Turin and Genoa BaHwav,
and tbey were also proposed by Steplienson for the Semmering
Incline of the Vienna and Trieste lina"

On railway eoires and their evil effects on the rolling stock,
Mr. William Bridges Adams has addressed the following letter to
the ' Practiail Meelianics' Journal :'

" On railway curves it is a practice to elevate the outer rail
above the inner one, with a view to balance the centrifugal force
by gravitation, — a practice that obtained on the highway curves
ill the old coaching days of high speeds, and which still obtains
in the sharp curves of the anipliitheatre, where both horse and
rider leau over towards the centre of an angle corresponding to
the speed.

"But in the old coaching days the wheels on either side were
enabled to vary their speed to suit the length of the curves they
described, and the inner wheels made fewer revolutions than the
outer. So, also, it will be found in the amphitheatre that the
inner legs of the horse makes shorter strides than the outer.
Otherwise the animal would be driven against the barrier — his
leaning inwards notwithatanding.

" On a railway wheels proper, i. e., revolving independently of
each other on the same axle, are not used, but there is a contri-
vance intended to produce a compensation. The periphery of
each wheel is coned, or baa a varying diameter, largest internally
and smallest externally. Theory saya that the centrifugal force
teuda to drive the wheels against the outer rail, and so bring the
larger diameters into action thereon, and tlie smaller diameters
into action on the inner rail, thus producing compensation and
curvilinear movement

" But theories are not sonnd when they do not take into ae-
coimt all the data which may affect them. If the play or width
between the raUa, j, e., the gauges, be not wide enough for end-
lung movement of the axle, this conic compensation is defeated.
And, if the axle be so fixed in a long carriage oi engine that,
while going round a curve, it cannot point to the centre of that
curve, the compensation will he imperfect. The actual condition
on almost every curved line, whether the proposed curves of the
engineer or the multiplicity of short and sudden curvatures and
variations of rail suiface induced l)y wem oi im'^e'cfctt. 'Hwcbman.-

EKGiNEERING FACTS. [Dir

aliipf the actual condition involves both the defects — wrong
position of the aslu and wrong diameter of the wheeL

" The resuU ih that the wheels become, not rollers, but sledge«^
and induce that grinding vibration which physicians object
for their nervous patients, and the esiatence of which is ignored
frequently by those said to be experts.

" The proof — Centrifugal force and inward gravitatii
nicely calculattsd and balanced by engineers to determine the
exact elevation of the outer rail above the inner due to each
Tbeoi'etically, the weight of the engine leaning in-
wards should tend to grind the inner rail, but the exact oppoaita
< the constant fact. The inner edge of the outer rail
ground away and polished, even when on a curve of 600 ft,
riulius the outer rail is elevated 6 in. — equal to an inchne of one

e niEchanical reason for this is that the inner wheels ru;
ning la ijiameters too large for the path of the inner rail, a
acting with an outward thrust that wholly overpowers the gravis
tation inwards, that very gravitation tending to increase the bit4
iion of the inner wheels, and to force the lighter loaded
cuter wheels to ' skid ' and slip against the outer rail with a forC4
tending to burst the fastenings by the flange actioiL If, ondec
these circumatanceB, there be a yielding or sinking of the inner
rail, the adlieaioa of the inner leading wheel will be lessened,
and the flange force of the outer wheel will be increased, tend-
ing to throw the engine off internally. If, on the contrary, thero
he a yielding or sinking of the outer rail, the Sange force will ht
weakened, and the adhesive furce of the inuer wheel will tend to.
tlirow the engine off externally.

" Other things being equal, the greater tlie length of the
wheel base compared with its breadth the steadier the engine
will run on straight lines, but the greater will be the risk of its
H getting off the rails on curves unless provision be made to keep
^h the axles true to the curve centres, and to ailjtist the diameters
^B of the wheels to the respective lengths of the rails.
^H " Such provision is not made— is scarcely thought of being

^M made — and as a general rule would be thought a heresy, would
^H be objected to, and yet herein lies the wliole of that " mystery "
^^L so frequentiy adverted to aa tVe »i\u'unti. -oiA w he coiii{)i^

I

I

^HniLWAn..] ACTION OP WHEELS DPOH EAILS- SM

^^leaded, wheii railway accidents occur by eugiti«8 getting off
the line.

" All railway practice is full of the proof. WLy do nils
glisten I Why do the treails of wheels work ink) deep bollowsl
Wliy are wkeel flanges cut to the sh^^ne:^ of knifeblades t AH
this is proof positive of sliding frietion, and not of roUiiig.

" And now to the proof n^ative. A resident railway eu-
ineer applied to four engines mnning on a line of sharp curves
md steep gradients fonr classes of tyres of different qiuditicf,
ying in price from £75 per ton to £25 per ton, representing
reby their various degrees of durability. To three of tlie
"engines the wheels were applied on the uanal mode with the
beat tyres. To the other engine, working un<Ier far more un-
favourable circiuostances, the lowest class tyres were applied, so
that tbe wheels obtained conipensution in curves. The result
was that the inferior tyres exhibited about two and a half times
the durability of the best. And, ss action and reaction between
tyre and wheel must be equal, the saving on the rails must have
■Jteen proportionate to the saving in tyres, i.e., the seven years'
ration grew into seventeen so iar as that engine was concerned.
" So much for the pecuniary advantage in wear. Yet this pe-
Inniary advantage represented also a corresponding element of
fety. Possibly, this practical tact, still only a portion of what
eeded, may in process of time and by the help of accidents
[ow up into recognition, and, like the grain of mustard seed in
e parable, become multiplied till that source of railway acci-
mta disappears."

DIVISION SEVENTH.

IKON,

The subject embraced in this division is of paramount iuiport-
uce to the engineer, and of the most comprehensive character,
embracing, as it does, so many details of siaentific and practical
importance. It would be idle to expatiate in this work upon
,tbe moDj- aad varioua applications of tUia m.ufit valuable ai .

r

I

■iid ENGISEEKING FACTS- [Dtr. TI!.

itietala; suffice it to say, that to become thoroughly acquaintol
with its various conditions and qualities is the first step tonoida
the aucceseful applieatioa of it to the variona works met with
in engineering practice. The various eourcea of iron, as i
known, is from the different ores which contain a large pro-
portion of pure iron in combination with carbon, foilphar, phos
phonu, and other haaee. The most common ores are a
lowB ; — Magnetic oxide of iron, which oonsista of 3 atoms e
iron in combination with 4 of oxygen (Fe.j O4) and contains
ing aboat 73 pet cent, iron. Red IJiEmatile, or peroxide of ii
contains 2 atoms of iron in combination with 3 of oxygei^
(Fe.Q 0)), and containing 70 per cent iron. Brown 3antatit«f
a hydrated peroxide of iron, is composed of 2 atoms of pep*
oxide of iron, 3 atoms of water, and containing 60 per cent, iroa:
Blaek-band Irot^loTie, a carbonate of iron, is composed of I atom
of protoxide of iron in combination with 1 atom of carbonic acid
Fe. + C0°), and contains 48 to 50 per cent. iron. Iron it
abo found in combination with sulphur, called iron pyrites, but
tliis is unimportant, such an ore being useless to the iron n:
Dwing to the pernicious effects of sulphur in iron, whether ex-
isting in the fuel or the ore itseli

The process of extracting iron from its ores may be briefly stated
as follows: — If the ore to bo operatud qpon is a carbonate, it ia
reduced by means of heat, which drives off the carbonic aoidi
while a quantity of lime is used to remove the earthy conatituenta
with which it combines, forming a glassy refuse, known aa " slag."
The iron thus remaining in the furnace is principiilly oxide, but
has its ojfygen removed by the largo qiwntity of carbon with
which it is in contact, and the liual product is a carburet 0*
iron, known aa cast iron, it being a mixture of pure carbon and
Other impurities, however, frequently require removal)
such as sulphur and phosphorus ; this is effected by the action of
chlorine, which is introduced into the furnace in the form of
chloride of sodium (Na. CL) or common salt

Theironofcommerce, as ia well known, exists in three different
forms, mallaahh or wrought iron, east iron, and steel Malloablt
the metal in its nearly pure state, — steel having a certain
proportion of carbon in combination, while cast iron has still a.

The processes hy wiiich theae -^anoMa comiitlooa of iron

PRODUCTION OF IRON AND STEEL

ubtaiJJed are very Dumerous. The great bulk of irna obtained i«
first rcdticed to the stats of ea^t iron, then the carbon ie extracb^d
by means of " puddling," or exposing it to the oxygen of the
atmosphere iu reverbcriLtory furnaces in a melted state. Tlir
oxygen combines with one atom of carbon to form carbonic oxide
<C0), which burning with a blue coloured flame cotnbineB witli
another atom of oxygen, and escaping as carbonic acid (CO^). The
iron by this process loses its carbon, becomes agglutinated, and
is taken ont and " shingled," after which it is worked up with
the steam hammer. Steel ia produced from wrought iron by in-
troducing into it the necesaaty amount of carbon, and this ie
effected, according to one process, by introducing into a retort
bars of wrought iron along with carbon, the whole being main-
tained at a red heat for a considerable time. This is the most
common process of making stee! from wrought irou ; bnt lately,
l>oth. wrought iron and stee! have been obtained by a peculiar
process direct from the ore.

Having thus endeavoured briefly to explain the processes of
obtiuning tli6 different eonditione of iron, we shall return to the
conaideration of " pig " or " east iron," and in doing so, the first
step is to ascertain, as far aa. possible, the exact component
{Nirta of the difierent samples of cast iron, and what constitutes
hardness and softness, &c., in iron.

As this is a subject the chemistry of which is still to a gi'eat
extent unknown, we shall simply give the experience of practical
connection with observed facts.

The latest solution of the question as to the state of carbon
st iron ia given by William Crossby, F.C.S., which we extract
the ' Chemical News:' —
I have long been of opinion that anytliing throwing light
upon the chemical constitution of caat' or wrought iron and steel
b of great importance, and I eubmit the following considerations,
which are partially supported by experiment, as tending in this
"irection.

In analysis of cast iron the carbon is generally shown in
statesp-viz., combined and unoombined; combined as a
fusible carbide, uncombined as graphite disseminated throughout
the mass of the iron; and, according as-the graphite
Itide preiloaiinatea, we have grey ov white iioi\. T.^\%'«\v&a\&«u&

I sea ESGISEEBING FACTS. [Dcv, VI

e ite peculiftr propertioa to containing but little graphite and
mnch carbida Tlie grey, on the contrary, contains but Iittla
arbide and much graphite, or fiee carbon.

" I don't know why theae views should be held, never having

wn any reason given. They are the views, however, generally

f held, aa may bo easily shown,

"111 the ' Chemieal News' for Saturday, January 31, 18
t paper on the Chemical Constitution of iron, &a, by GenenJ
Sobrero, of Tuiin, the following passage will be found: —

" ' . . . The cast iron is rotated nntil the moment it soli-
diBea; for this reason, carbon cannot crystallise separately, bnb
emains in combination, hence white iron results.'

" P. A, Able, Esq., in a lecture at the Eoyal Inetitution. April,
27, 1860, says:—

' In looking at these specimens of cast iron, you will be a
OSS to discover a very considerable diiference in the appei
I of moat of them — indifl'erence which is borne out by folly aa
graat a variation in their phyeical properties and chemical com^
position. HerB is a very dark eperjmeii with glistening fracture,
containing a considerable portion of carbon in a peculiar conditioiii
— in the graphitic forra, as it is allied.'

" Miller, in hia ' Inorganic Chemistry,' p. 879, says: —

" ' In many varieties of cast iron the carbon eidstB in

distinct forms — one portion being chemically combined with tlia

metal, the other matdianically diffused through it as graphite —

the scales of which may be distinctly seen with a magnifying

i when the surface of a newly fractured bar is examined;

se scales remain unaet^id upon when the niutal is dissolved

I in dilute acid.'

" I liave frequently had occasion to examine samples of grey
'on with a lens, and never yet have I seen the scales he
I ferred to ; and I believe if grey iron he carefully examined, it
'je found to be made up, not of iron and graphite, but of
I crystals aggregated together, aiid containing carbon and iron
I chemically combined. When iron is acted upon by dilute acid^
I'Hs shown by Calvert, the carbonaceous matter left possesses Uie
s form, and occupies the same bulk, and, in fact, has the
■Asnjti appearance in every respect as the iron from which it has
"Mai nod.

F

^^ " But, fur the sate of argument, we will suppose that in fe'rey
imn the carbon is really aa graphite; and here at once a di9i-
cnlty meets us. How is it that grey iron ia more fluid than
white ironl In grey iron we have almost a pure iron (which ia
very difficult to make fiuid at all) merely mixed with carbon.
In white iron, on the contrary, the carbon is chemically com-
bined, and we all know liow much more fluid melted carbide of
iron is than iron free ^m carbon. How is it, too, that the
graphite does not separate when the iron ia in the fluid atate t
The graphite itself ia infusible, and its specific gravity niuuh
lower than the iron in which it floats, one would think that it
would separate from the iron and rise to the surface. TTiere are
those who answer these questions by saying that iron ia capable
of dissolving graphite when it melts, and again liberating this
graphite when it coola, while others say that a carbide of iron is
iormed when the iron melts ; this carbide ia again decomposed
on cooling.

" I think 1 can prove that neither of these explanations can
be correct, or, indeed, any other where it is assumed that the
carbon exists in the two states, combined and ancombined.
First, let ns see how far the theory that the graphite, when the
iron melts, is converted into a fluid carbide, holds good. Before
doing this, however, let me draw attention to the fact, that iron
made from the same stone, and under nearly the same cireum-
atanoes, whether white or grey, contains about the same total
oentage of carbon. For instance, the carbon determined by
mbuation, in three samples of grey and three of white iron
pve the following results ; —

GEEY AND WHITE IRONS,

Grey. Avorage.
Carbon 3 -94 )

Wliite.

Diffarc

Average,
cent. = S'SS i = 3'87 per caut,

. -Oi per cent,
that these irons are melted,

"We will assume, now, that these irons are melted. The
e is already a carbide ; the grey is converted into one by
lelting. Here we have, then, two irons in the fluid state both
containing the same quantity of carbon, yet one more fiuid than
the other. Let them cool and soKdify. How ia it that one
iffipamtes graphite aad the other doeft axM Sut anly thia^ but '

ENGINEERING FACTS. [Drv. V]

I wo actually know bofotehand which of the two will liberate ths
I graphite, or, in other words, be the greyest. If this theory
correct, surely graphite ought not to be separated in the one ci
and not in the other.

" 2. The theory of Bolutioa This, I think, is even more un-
tenable than the one already referred to. Faraday haa shown
that iron is capable of combining with C per cent, of carbon.
I Very few commercial irons contain more than i per cent, ai
if a. portion of this be uncombined, I cannot underetaDd the ii
dissolving without at ths same time combining with it, much
J same way, that a solution of chloride of iron, and containing
excess of iron, will dissolve more iron by uniting with this
n to form more chloride.

" There is an experiment mentioned by Carey, I believe re-
peated by Wylde, and confirmed by myself, where a little eulphidt
of iron is added to melted grey cast-iron; the iron immediately
changed to white, with the hberation of graphite, which rises afe
e to the surface of the iron ; and I hold that if thb graphite
had beea meroly mechanicaily mixed, and yet unable to sepante,
[ separation would not have occurred on the addition of sulphide,
f for the quantity requisite is not sufficient to produce any ma-
terial change in the physical properties of the iron while in »
[ fluid state.

" We will now look at these questions, assuming, first, that
I there are two carbides of iron, and that ca«t-iron is a mixture of
I the two, with an excess, perhaps, of metallic iron, or of iron al-
I loyed with siliciura, calcium, manganese, &c The one carbide is
[ grey and aoft, the other white and hard, and for reasons explained
I hereafter we must suppose the grey to be a higher carbide than
I the white. We ciin now easily account for the non-eeparati
l.of the graphite when grey iron is melted, the grey appearance
r being due, not to this substance, but to a fusible compound of
carbon and iron. But it may bo said that graphite does separate
when the grey iron is melted. Admitted; but how small a per-
centage of the total carbon present separates in this manner ; and
this quantity can be accounted for as resulting from the decom-
l position of the grey carbide; in fact, this brings us to one of the
■^rinci^ml properties of grey iron, viz., its instability. Like some
' the complex conipoimda known \a a\^ms^ ^tva-QA^rj,

i

,] GREY AKD WHITE IRONS.

jht changes are sotiicieiit to effect its decomposition. Thin ia
shown by the liberation of carbon when a little salphide of
iron is added to it while in the melted state, also b; its non-
production excepting when the furnace ia in the very best work-
ing condition; very sudden changes of temperatvire, too, may
effect its decomposition. In many of their properties the grey
and whit« carbides of iron may be compareil with the two com-
pounds of carbon and hydrogen C' H* and C* H*. How much
more stable is the lower carbide than the other; and how readily
is the latter decomposed with liberation of carbon, and formation
of the less highly carbonised compound.

" For the purpose of testing some of these views by experi-
ment, I broke four pieces from a pig of very grey iron, and put-
ting three of these in separate plumbago crucibles, each crucible
was covered and coated with fire-clay, and then put into a wind
furnace, which was gradually ui^ed to a white heat The tire
was then allowed to bum out, and one of the crucibles removed,
which was labelled No. 1, The (ire was again lighted and urged,
and again allowed to cool, and another cmcibk was then re-
moved, and labelled No. 2. The third was again treated in a
similar manner, and then labelled No. 3.

" My object in melting in carbon crucibles was to prevent
access of air to the melted iron ; if any air did succeed in pass-
ing through the crucible it would be deoxidised by the carbon
of the crucibles.

" The button of iron found in No, 1 crucible was coated on
the outside with ' kecch,' or kiah, as the graphite ia genemtly
called. Wlien the button was split, the fracture showed it to be

* Ko.' 3 iron.

" The button of iron from Na 2 crucible had less graphite on
the outside, and, judging from the fracture, it might be called

• No,' 4 iron,

"The button from No, 3 crucible was 'mottled,' or 'No,' 5
iron; it was quite free from graphite on the outside,

" Thus, by melting No. 1 once, ' No.' 3 iron was formed ;
melting a second time, ' No.' 4 ivon; and a third time, ' No.' 6
iron.

" I explained these changes by supposing that in the first
toeltu^ a sBiai) quantity of the grey iron li&d been. decom^<iQed.

I
I

EH6 E^•GINEER1NG FACTS, [Drv. VII

and a little graphite liberated ; in the second melting ranr
phite separated, but the graphite liberated from the firat melting
had again united to form the white carbide ; in the third melting
all the graphite which had previously separated again combined,
and ' mottled ' iron resulted.

" I afterwards determined the carbon in the buttons of iron,
and the results obtained appear to confirm the above views.

" They were as follows ;— -

3rd „ , . . . = 3-96 „

"The low results obtained in No. 1 ia accounted for by thrf
graphite hherated in melting. In No. 3, the graphite had agaia
contained, hence this discrepancy ia not seen.

" Another fact, which seems to support the view that the
carbon in grey iron is cbemically combined is the losa nf carbon
in the form of volatile carbides of hydrogen ; when iron is acte<t
upon by acids, no matter how grey the iron may be, or hgw
lai^ the crystals, there is always some loss in this manner, bo-
sides a liquid oily substance formed, which floats on the surface
of the acid.

" In conclusion, many writers mention the fact, although 1
have never tried the experiment myself, that by exposing a h
of wrought-iron to a high temperature in a current of coal gs%
it is possible to convert it into grey iron. Now, if grey ire
contains large flakes of graphite disseminated throughout i
mass, I vrould ask how these flakes can possibly enter the potoi
of the bar and get into its interior in an experiment of this kindf
T can understand the outer coating of iron acting as a carrier of
combined carbon in the inner portion, and by this means the.
bar of iron increasing in size and assuming a crystalline form;
hut I cannot understand a flake of graphite being first formed
on the outside, and then forcing its way into the interior, chang-
ing the properties and form of the bar."

The quality of ii-on, besides being afi'ected by the proportioa
of carbon contained in it, is also materially atlected by the ia&a
ence of the blast in the process of reduction Vast improvemenl
Jiaa beea eSected in the iiomnonaiacVQia'^i^ 'i^B^lsua^iI.^i»b

Ikon] HOT-BLAST IRON. MT

blast, although in some trona it is said tliat sach has a ileterior-
atiDg influence. Aa it la, the Baving of fuel is immense ; and some
fuels are now used which, with the cold blast, would have been
absolutely worthless.

In connection with this subject we quote the fnUowing froiD
the 'Meehanica' Magazine:' —

" When we consider the immense interests involved in the iron
manufacture, it seems strange that the pTccise influence of the
different applications of the blast on the quality of the iron pro-
duced in the blast furnace has not been investigated with the
care dejnanded hy the importance of the subject. The most
eminent men of science ate at variance when attempting to ex-
])Iain the principal phenomena resulting from the action of the
tuyeres at tlie hearth.

" If we remember that a weight of nearly 14 tons of air is
mnsumed in an hour in some of the large famaces — an emonnt
nearly three times as great aa that of the aoUd materials; the
nre, flux, and fnel — it must be evident that the volume, the den-
sity, the hy^scopie state, the chemical constituent^ and lastly,
the temperature of the air employed, must exercise a powerful
influence for good or for evil upon the products of the furnace.
The action of the air will evidently not merely confine itself to
the ' yield' or quantity, but will also exercise an influence on the
'make' or quaUty, of the pig.

" The density of the blast employed has a considerable infla-
ence on the emelting operations, 'and it is principally determined
hy the dimensions of the furnace and the kind of fuel employed.
The season of the year also requires some variation in the pres-
sure of the air; and when its density is diminished hy the heat
of summer, the blowing engine has to make up the deficiency by
increased speed, in order that the fiimace be supplied with the
requisite amount of oxygen. Before the introduction of blowing
engines worked by steam, great difficulties were encountered in
the use of eoke and coal in the fumsce. About 2 lb. to the
square inch is the miuimura pressure of air now employed, and
dtiB deneity is generally increased with the density of the fuel
3 it reaches 3^ lb, to the square inch. Con-
table difference of opinion still exists as to the precise shape
a and the exact number to Aie eTO\i\a^«A. Ife. XiMs-

KSGIKEEBISG FACTS, !

mil patented in 1855 (No. 1730), 'a mode of constrnctinK nozdi
pipoa BO that they should deliver through one tojrere two or w
juts <jf Llost, hot or cold, of like or diiferent densities. '
nox7.le pipes may be divided by partitiona or be doable^ one
ing within the other, bo that the outer one delivers an animlm
jat, Olid the two jets may be supplied from different pipes, ant
he of Jiffi-rent densities or tempemturea.' We do not knon
whether this plan has ever been tried. The blast ia generall]
apptiml by means of three tuyercE^ but as many as ten or twelvi
iioulea are sometimes used. The small tuyere system i
(-.jiilly oiloptcd in Scotland. It is to be regretted that esact data
do not exist as to the relative values of the two systems.

" The hygroscopic state of the air, or the amount of moiston
oontoiiic"! ill the atmosphere, is another potent element of i
ceu or failure. It is estimated by Mr. Trurau, that about 21
tens of air are consumed per ton of metal, say dark grey pig ironj
and thus, with a make of 120 tons per week, the amount < ~
blnat cimsumed would be 3,000 tons. Accordin)^ to Daltoi^
tbo air in England contains about 1*42 per cenL of moistnrB ii
dry wuatlier, and more than double that amount in wet weather,'
NO tlml wu have a quantity of from nearly 50 to 100 tons tA
water diachargod weekly inte the furnace. This is, no doub^
tliu vxpliuiation that there is less fuel consumed and a bettei
quality of motal proilnced in winter than in summer. '
OTUMO of ntako ie, in fact, estimated to be from 4 to 5 per cent
CKat«r durin}! tlie winter months. The chemical constituents of
atiuMphoric air being invariably the same, it could only be by
artitioinl nioait' that any action on the furnace could be Bought
fi>r by diatigiiiii lh« uhuiiiioal composition of the blast. Vorioua-
attomptfi ill tliis direction will be found recorded in Her Majesty's
latent Oftioa Thus we find one invention (Patent No. 6,948,
Old Law), proposing tti inject 'pure hydrogen gas' into the blast
furuaot^ Apart from the risk of explosion, the great expense ii
jirgeuriti);; tin' gas would of itself form an insuperable bar to the
praotiual iiitroiluiition of this process.

" The prcoiee effect of raising the temperature of the injectedj
air to about (110 deg., or the use of the liot blast, is still a d»
butoable point with those concerneil in iron-making. The qnea

k iian

tOMiy b

i into tknw «e'£«xa)A\uia&k-, '&«%

^^

liin.v.1 CONSUMPTION OF COAL IN HOT BLAST, 999

iicing the inAaence of tlie bot bUst on the oconomy of fuel, tliu
second its action on the quality uf the iron produced, the thinl
being the coniniereial or traJo value of the hot blast

'' There ia no doubt that the consumption of furnace coal is
i-^diiceil by the hot blast. The saving effected varies greatly
with different kinds of ooal and ore. Taking the coal used in
the stoves for heating the blast into account, the saving effectwl
has been estimated at 3 cwts, of coal per tun of pig Iron in
Wales, and from 6 to 7 cwta. in Scotland. Yarioua reoBons
have been given to account for this economy of fiieL By some
it has been ascribed to an annulling of the cooling efFocts of the
I'lild blast on the combustion of the furnace; by others, tliat a
ijot blast supports combustion better than a cold blast; the rela-
!ii-e proportions of the oxygen and hydrogen on the air, are, how-
.'ver, unaltered by the addition of heat. Mr. Truron ascribes the
i-cunomy effected by the hot bkst to a reduction in the quantity
■if coal required in the furnace from the extraneous heat thrown
in by the blast, as a reduced proportion of coal to ore is always
-ueceeded by an increased quantity of iron produced. The
umount of coal required in the furnace being thus leseeneil, there
!» a less volume of blast Tequireil, the additional result being a
iliminished consumption of fuel in the upper parts of the fumaoe.
Briefly stated, the economy of fuel effected may be ascribed to
two canses; the reducing power of the heated blast injected at
the bottom of the furnace, and the lesser proportion of carbons
in the fuma<M to the volume of the blast.

"With regard to the influence of the hot blast on the quality
of the pig, we are stiU somewhat in the dark. There is no
■ ioubt, however, that the use of such a powerful means of acting
on the furnace may, in unskilful hands, lead to bad results. Mr.
Robert Mallet, in hia work ' On the Physical Conditions Involved
in the Construction of Artillery,' ascribed the ' much discussed
and unquestionable (!) inferiority of hot blast iron over cold ' to
unnecessary heat of fusion, caused by an unskilful use of the
hot blast ' Unnecessary heat of fusion injures the quality of
the metal, as unnecessary heat of "pouring" injures the quality of
the casting. It does this in two ways — by the introduction of
foreign earthy and alkaline baaea, which greatly reduce the co-
hesion, and far more by the great increaae of surface, jjroduced

r

I
I

t

270 ENOINEERINC FACTS. |T):v. VII

by extreme elevatiou of temperature, in tbe disEeminated pUlea
of graphite. These, scattered through the mass, like i
homhleade in granite, present at their innumerahle planea t
cleavage almost no cohesion ; but these planes are, in accordano
with the general law of arrangement, in planes of least preasutq
found mainly to coincide in parallelism with thoae of the oryatal)
of the iron itseU (i. e., the carburet of iron, which constitutes th<
metal of cast-iron chiefly), so that the total deterioration i
strength is very great; and this is, in £ict, the secret of the muc
discussed and unqueationable inferiority of hot-blast iron on
cold; nothing more than the elevated temperature introduced it
the blast furnace.' Fully admitting that the injudicious use c
the hot blast may pi'oduce the injurious effects ascribed to it h
Mr. Mallet, we nevertheless differ from him in his sweeping con
demnation of the process. To corroborate our opinion, we will
further quote the following : — Mr. Hoilgkinson, in bis report ta^
the experiments on hot and cold blast iron, made by Mr. Hodg
kinson and Mr. Fairbairn fur the British Association, says:
is rendered exceeduigly probable that the introduction of a heatei'
blast in the tnanuiacture of cast-iron has injured the softer icon^
whilst it has frequently mollified and improved those of a "
nature, and, considering the small deterioration that the ii
quality No. 2 have sustained, and the apparent benefit to th06«
of No. 3, together with the great saving efiected by the heated
bhist, there seems good reason for the process becoming so gone-
ltd OS it has done' Respecting the specific gravity of hot h"
iron, we may state that some years e^o, Dr. Thomson carefQlly
analyzed the chemical constituents of hot blast iron, and 1m
tbund, as a general result, that the specific gravity of hot blait
iron is greater than that of cold blast, and an average of eevend
experiments showed that the hot blast increases the speeifie
gravity of caal^iron by about l-22d part. Dr. Thomaoa tisa
found that hot blast iron contained a smaller proportion, of car-
bon, siHca, and aluminum than cold blast iron

)W coiue to what we have termed the commercial s
trade influenca of the hot blast on the quality of iron.

" The best English ironstone is the argillaceoiis or clay iroih
tne, and it requires the cold blast to work it in quantitiea
IB Itou produced is iieat\ier 'teA aVift' "a-ist ■■ laAi. dosvit, and fa

liioK.] INFLUENCE OF HOT BLAST OK QPALITY. 271

iliua nt^ver brittle, wliether hot or oild What ia called 'cinder'
IS the refuse of the puddling aarface. It contains a large per-
centage of iron comhiued with impuritieR that have been ex-
pelled hy the puddler from good iron, or 'mine,' The power
given b; the iiot blast in extracting the ii'on from aniongst these
impurities has greatlf increased the production ; hut tlie produce
is rendered very inferior by an admixture of this mnterial. It
is called 'cinder iron.' We do not assert that the hot blast in-
jures the quality of the icon. As we mentioned before, its prc-
ciae effect has not been oacerlained nith any precision. But we
have seen that the hot blast may be used to extract iron from
H[iy material, fi'oni the best to the worst The cold blast can
only be applied to the be&t ore and fuel, it cannot be used to
njalte 'cinder iron ;' and thus the very name of 'cold blast iron"
is to some extent a guoruitee as to its quality. The introduc-
tion of the hot blast has thus been a great benefit as regards
luantity of produce, but as regards t/aalify, it lias offered facili-
ties for 'scamping' the work, of which, unfortunately, bat loo
many have availed themselves. The hot blast has also been the
means of permitting the ironmasters to use raw or uncoked coal,
instead of the desulphurized coke. It is evident that more itn-
^jiTirities are liable to be worked up with the iron when raw coal
^& employed. The Scotfib coals are generally so uufit for coking
^^mat they often lose 55 per cent, in the process, and the intro-
^Rnction of the hot blast, by greatly economizing the coals there
^employed, has raised the iron raanufaoture of Scotland to its
present importance. Within twenty years the make of iron in
England has been trebled; in 1840 the total produce was a
little less than 1,400,000 tons; in 1860 it was more than
4,150,000 tons. This progress, however, is more of a striking
than solid character. Of the 1,400,000 tons of iron produced
in 1840, 770,000 tons of this quantity was cold blast iron ; of
the treble quantity in 1860, only 150,000 tons were produced
by the cold blast. Figures, however, do not give a true account
of the produce of the iron manufacture. Mere quantity is a
very rough estimate ; quantity and quality combined ought to
taken into account. Double the resisting powers of the iron
^uced, and for many apphcations leas than half of the qnan-
js required

I
I

272 EHOINEEHING FACTS. [Dir. V]

"Tlie value of raising the temperature of the blast is thu
wthor pomt upon winch muuh difference of opinion still e
i we have seen, sojue say that hot-blast metal ia greatly i
ferioT to cold-blaat, in contradiction to others who assert the co
trary opinion. The exaut amount of economy of fuel efiectei
by the use of tlits process is another subject of dispute. K"
definite data exiit that would warmnt our drawing concluBtoi
us to its precise influence on the molecular atructore and chemi
cal constituents of iron. We consider that this great uncertainty
is a liisgrace to the iron manufacturers aa a hody ; and withoui
overlooking the fact that a strict inquii'y iuto the matter ti
involve great expense and difficulty, we nevertheless consider i
very extraordinary that the exact value of a process emplpyei
for the last 36 years, is still involved in obscurity. The f
soema to be that the manufacturers, on the one side, ignore thi
deductions of theoretical science ; while, on the other, laboratoij
I'hemiats refuse to consider the practical requirements of mana
faoturing on a large scale. The only means of arriving at thfl
truth would be by the labours of a scientific cnmmission, meetii
the iron-makers on their own ground. The usual way adopta
in England in encountering these questions, is to summons I
host of witnesses before a Parliamentary Committee of Inquiry,
and the culminating result of this expensive procedure is a
voluminous blue-book, which is read by nobody. The evidenca
given is, no doubt, often very valuable in its way ; but who ia
to separate the grains of wheat from the mass of chaff 1 Tbiff
separation could only be effected by the light of science ;
by orators from parliamentary benches, hut by chosen men, takei(
from the foi^e, the laboratory, ami the workshop."

lu the above article we quite agree with the writer in saying^
that much of the inferiority attributed to the hot blast pig is d
to the amount of " cinder iron " worked up with the good p _
and this " cinder iron " contains impurities sufficient to contami-
nate laige quantities of good iron. Were special attention di-*
rected to the complete purification of the iron extracted from
" cinder," then " red and cold shortness " would so far disappear
ich of the commercial pig. Upon the purification of sn^
" cinder," A. L. Fleury, chemist, Franklin Institute, PhilA>
deJpliia, has published a circular Lu lUo " Scieiii-ijic Amen'eanJ' de

N.) EXTRACTION OF IKON FROM FTrBNACE CINDEES. 378

w

I^Tfcnjjtive of a new prooess of oxtraoting good iron from " cinjer, in
wliich he states that ho " baa succeeded in extracting good wroiight-
iron and steel bom the waate cinders of puddling and reheating
fumacea, which have hitherto been considered a nuisance in their
vicinity. Ue states that, from chemical aoalyaia, he is aesured
that such, ciuders contain from 25 to 50 per cent, of iron, com-
bined with Bulphur, silica, phosphorus, and alumina, forming a
hrittle compound. Near the lai^e ironworks at Troy, N.Y.,
tliouaanda of tons of these cinders are spread over the roads, aud
in every 100 lb. there are about 35 lb. of iron. By reworking
this cinder with lime and charcoal, iron bad been eBtraoted, but
it waa invariably red-ahorl (brittle at a red heat), as the sulphur,
silicon, and phosphorus remaned combined with the iron. Num-
herlesa unsuccessfid efforts bad buon made to work this cindvr
I'uonomically. Mr. Fteury states that the problem of extracting
!lie iron from the cinder and removing the impmities, was
ii.ilved by taking advantage of the chemical fact that unslacked
liiinit lime possesses the property of decomposing silicates doring
lliu act of being slacked with water. He mixed » proper qmm-
tity of powdered burnt lime, with iine ground iron cinder, wetted
the wbole with water, and exposed tlie mixture to the atmo-
sphere. When this compound waa dry, it waa placed in a com-
mon puddling furnace, treated like pig iron, and 50 per cent of
wronght-iron waa obtained. This product, however, waa some-
what red-short, as it contained traces of sulphur, but the impurity
—Mr. Fleury informs us — he afterwards extracted, by mixing a
" ,e salt with the water which he employed to wet the lime
ixed with the cinder; and a good quality of iron, we are in-
med, can he invariably produced when the operations are pro-
■tly conducted. It is also stated that the cost of preparing the
ider does not excued 2 dols. per ton, aud the operation of
Miting can be executed in puddling, blast, or other suitable
The invention has been patented in America aJid

^The advantages of the Lot blast system, however, are very
eat, and especially with the Scotch coaL Mr. Truran ascribes
b economic superiority to two separate causes —
!* The fli^st is, that the heat thrown into the furnace along with
k.blas^ permits a corresponding quantity of cual to be with-

r

I

I

!7J ENGIHEERING FACTS. [Div. VII,

drawa from the burilen of materials, and a proportionate reiliic-
tion in the volume of blast The cffL'ct is seen in the angmeu-
tiition of make, but not in any eaving of fusL The sucond c
ia, that the reiluixJ volume of blast, and the lat^'e amount <d
lieat which it carries witli it, cause a diminished eonsumptioc
fuel in the upper pacta of the furnace, the result being that a;
(quantity of fuel is saved at the furnace greater than what wouttt
bii due merely to the caloric introduced by tbe blast,"

The quality of different aamples of cast-iron can be pretty
well ascertained fay the appeaiunce of their fractui'e, those having^
a laT),re crystalline appearance being of a soft and tough natural
those presenting a fine grey granular appearance being of a hard'
and brittle nature. The heat test, however, ia tbe application iif
the hammer and chiiwl or file in the hands of one who boa
practically worked in iron. The following is a te
mended by a writer in the ' Mechaniai Matjaaiie ' for aacertain-
ing the quahty of iron wlien in a melted state: —

" When melted pig iron is tapped iuto a ladle in modenlA
quantities, so that excessive heat may not prevent pretty olwa
observation, it will sometimeB be found to boil violently, »
times its surface is calm from the first Now, if this molten it
id allowed to stand a few minutes until it becomes perfect/'
quiet, and is then carefully skimmed clean, ire shall find that k
beautiful irridescence covers ita entire surface, due to the consluut
breaking up of the extremely thin film of oxide formed t
iron. Tills irridescence, frequently called by moulders the
' pattern of tbe iron,' may, on close inspection, be found to oc
i^ist of a mnltitudu of many sided or rayed stars, in constant ni
tion ; breaking up and vanishing, and forming anew with the
velocity of thought, and almost eluding the eye. It is a i
of extreme difficulty to deterraiae the number of vays ii
figure; we believe we are correct in saying five; ime tiling a
certain that their shape and character is invariable with eve^y
species of iron with whicli wo are acquaintbd.

"" This much premised, we would call attention to what we W

' Led to consider as a proved feet — namely, that the auS (^
different figures which make up the 'pattern,' in

the size ol grain o? \\w, wovi -wlwu in the pig. Unlit
itite, whicli is a \arga-?;KtiTic4wo\\,-*i'-Ki,'«^«;^'ni^4iii,^

^Kos.] UANUFACrrRE UF WKOIXHT IKuS. SIS

l^ient a large pattom, Fine-grauBei] irons, such as the grey f jrge

pig of aome of the StaifordBhire woriw, give aii exlreniely smnil

pattern. This diBtinctioa is, we miiieratand, so wtll mitrk«J,

that in some cases a glance at the melted iron will enable an

^■Uicurate opinion to be formed as to the siise of gi'ain ij) the pig."

^B Coming now to the manufacture of wrought iron, wu have

^neai'd of little novalty during the pa.4t year; but the puiMjere'

^^(tribe, which has raised the price of wrought iron to such a

height, points only too plainly to the necessity of puddling

by machinery, or superseding puddling altogether. Upon the

subject of puddling by machinery the 'Engineer' saya :—

" The present attitude of the South Staffordshire ])nddler8,
who threaten a stoppage, temporary at least, of the iron trade of
their district, renders it more desirable than ever that paddling
jhinery be perfected and generally adopted.
' Wbat is puddlingi It appears to consist in stirring a
intity of melted iron, and in bringing each portion of the
thole mass successively up to the surface. What is the iib-
of puddlingi Simply, by bringing each particle of the
d iron to the air, to allow the oxygen of the air to seize
and combine witli the carbon and silicon associated with
DU, Practically, it is only the presence of carbon and silicon
liob tender iron fusible in the cupola, making it, as wu say,
iron.' When desilicatiaed and decarbonised (for the silica
always carried off tirst in puddling), the particles of the iron
Dobere so much more strongly than before that a much hight^r
degree of heat ia required to separate them — so high a heat, in-
deed, that the iron will burn before it will melt. Iron thus
..cleansed, we need hardly say, ia ' wrought iron.' The primary
"jject of puddling ia accomplished by any means which will
■ing the particles of the melted iron succeaavely up to the air,
jn the other hand, carry the air through the iron. Althougli
technically a process of puddling, the Bessemer treatment nf
I pves much the same, if not the same, results. The diffei'-
j, so far as there is any, in this respect, would appear to be
it the Bessemer process cannot be interrupted, with a certainty
iccess, until the iron is thoroughly decarbonised or nearly so,
reas puddling is never carried quite to this extent. At the
high tampec&tuie at which the iron is kegt in fusion towartla

p

I

I

STfl FA'aiNEERTNC FACTS. [Div. Til

the Bad of the conversion by the Bessemer process, there is
01 less burning, and the sabsequent addition of ' spiegel-e
produces di^inctive, although generally excellent i^sulta upon the
product. Still there is a difference between Bedaemer metal and
puddled iron, and of such a kind that, thus far, the formi
inapplicable to many of the purposes of the latter. Whatever
may yet be accomplished in the mode of converting iron, we
must retain the pnddling process for a time longer. Bat it
caunnt be impossible, we should suppose, to contrive a machine
capable of performing what the puddler now does laboriously by
hand. It is true tliat his work is not nltogcther mechanicaL
He certainly has to use his eyes and to act with considerable
judgment. But there are tliousauiia of men who might readily
be trained to the necessary degree of observation and judgment,
^though unfitted for the perspiring task of raking and baUing.
What is wanted is a puddling machine capable of doing the work,
while the attendant, with a fair aptitude and some preparation
for the business, supplies the observation and directing skill.
(Japt^iu Warren, Hi. ToDth, aai otbera have inTented puddling
machiuefi, but they do not appear to have answered. Captain
Warren proposed a revolving cylinder, lined with fire-hricks,
and turning upon a horizontal asis oblique to its own. Melted
iron, placed within this apparatus, would thus be churned fiom
one end to the other with an energy corresponding to the speed
of reroluticm and the obliquity of the axis of the cylinder. Mr.
Tooth employed 4 cylinder so liqed with fire-brick as to present
alternate ridges and depressions along its internal length. This
cylinder was put in revolution upon its own axis, wliich was
lioriznntal, and the iron was thus successively carried up on one
side and allowed to fall again. Fair r^ults were claimed for this
contrivance, two years ugo, and it was especially urged tJiat^ in-
stead of the usual con^umptiDn of 35 cwt. or more of coal per
ton of pigs puddled, a very much less quantity was found to
suffice. On the other hand, it was represeuted that many of the
blooms puddled by this process were but little better than cast
iron, and whether this be true, or whether from questions as to
the validity of the patent, it was not thought expedient to push
the matter further, the fact remains that little or nothii^ haa
iioea heard of the ' mechanical ^uAvWm' fci ttve. -^aat, t-wo years.

P^DDUSG OF IRON.

F

^^ts actiun certmnly did not resemble that of llie puddlers hook,
and this, ws thlak, must be the starting p(>int in designing any
machine for the pnrpoee. By the correaiwndence of the " Mining
Journal-,' it appears that Messrs. Domeny and Leniut, imn-niastv-n
at Clos Mortier, near St. Dizier, liave invented and set tu work
a paddling apparatus, which consists of an adaptation of mechan-
ism to a series of ordinary puddling hooks. Tlie ilescription
given is in very general terms, and leaves ns uiiahle to form
anything like a judgment as to its real eucceas. There must be
many ways, one would think, of imitating mechanically the ac-
tion of tho puddling hook. Something like Scliroder's evapoi^
ating pans, as employed on sugar plantations, would, if the discs
were wrinkled or provided with ppjjections of some kind, at least
bring the iron well up to the air. Whether any material of
sufficient strength could be found to stand the heat would require
to be settled by experiment. The central sha^ would require
to be coated with fire-clay, ganister, or calcined silicate of mag-
nesia, and might even require to be made hollow with a circu-
lation of water through it. There is also a contrivance employed
for whipping e^s and creams, in which apparatus a pair of radial
amis revolving horizontally in opposite directions are provided
with stirring pina, set much like the teeth of a rake. It would
be interesting to know how far an apparatus of this sort, with its
aidiB of revolution inclined in a greater or le^ degree from, the
sarface of the melted metal, might be made to produce the eifect
of puddling.

"Not only are the ironmasters now at the mercy, so to apeak,
of the puddiers, but at the best the work of puddling is of a kind

I it which no human being ought ever to he employed. Besides

Pits laborious nature, too, it is moat nnsatiafactory to he compelled
ta work upon such small masses of metal as are dealt with in
tba puddling furnace. Puddling furnaces cannot now be made
larger than the size permitted by the range of the puJdler s hook,
and this must be hght, and therefore short, in order that even a
strong man may work it for half an hour or so in the high heat
1 to which the puddler is always exposed. As it is, a 3 cwt. charge
j^^iiB about as much as be can manage at a time. The time will
^Blome, will it not, when the least charge will be as many tonsT'
^H The difficulties to be oveniouie iu puddling by machinery, we

I

I

ENGINEERING FAr'I'S.

tliiiik, are very great, since nn machinery, however automatic,
iiicurp'Ji'ate mind in its actions.

1. more feasible plan would be to supereede puddUiiR altogetli
by a direct conversign of pure or wrought iron from the oi
The Bessemer process is not exactly a substitute for puddling,
being in a measure simply a process of forcing the oxygen
contact with the metal in place of exposing the metal to tbe
action of the oxygeu aa in puddling The converting vessels re-
duce a (Quantity of cast iron to a state of wrought iron in a few
minutos, the iron being kept all the while liquid. The additional
lieat required to keep the iron liquid during the proceaa of de-
earbonization is obtained by the direct combustion of the car-
bon in presence of the oxygen forced into the converting vesseLe.
The iron, however, by this process, although excluded from the
air as much as possible, suffers consideTable loss from burning.
The direct conversion of wrought iron irom the ore baa of late
received a certain amount of coaBideratJon, and abroad conwder-
ablo success has attended such operations, — much uf the foreign
bar importeii iiito England being obtained by thia direct prooesa,
A tiuscription of one prooesB of effecting such
in Tniran's " Iron Manufacture of Great Britain

" The production of wrought iron direct from the ore — tha
mode of manufacturing — has engaged the attention of
' practical and scientific men, and is practised to a limited
extent abroad; but the attempts made to reinstate it in this
country have hitherto been, commereially speaking, unsuccessful
and though the ores and fuels we possess are unquestionably
superior to the foreign for this purpose, fusion in the blast fur-
nace, and conversion into malleable iron by the puddling processi
ia pursued with all tbe bar iron now manufactured.

" Tlia conversion direct into malleable iron dispenses with, tbe
blast furnace and appendages, and the intermediate processes nf
refining and puddhng, and if successful, should result in the pro-
duction of a finished bar of superior quality, with a smaller con-
sumption of ore at a proportionately lower cost. In all experi-
ments on converting on this plan, the bar is of inferior qiuility, the
consumption of ore larger, and the cost of production augmented
over that attending the manufacture by blast furnaces and re-
Tlie caussti tending lo pio^uAc ^.^u ^SfibK.usji!. botwwao

mm

Iron.] JUNCFACTtmE OF IKON. aW

t)io reaulta of theory and practice are nutQerous, bat will receivo
from ns only a brief notice,

" The ore to be converted is ground to 8 coarse powder
in mixture with a quantity of carbonaceous matter similarly di-
vided, is chained into a reverberatoiy furnace not unlike the
OTdinary paddling furnace. The draught is forced to the pro-
duction of a high temperature, reducing the ore to a semi-liquid
^_ -slate, when, by dexterous manipulation on the part of the opera-
^Ltive, metallic iron is eeparated from the extraneous raatt«r, balled
^Bisp, and shingled as in the usual manner The theory of this
^Foperation is simple. The carhon of the carbonaceous matter is
1^^ consumed by uniting with the oxygen of the ore, and the metal
is left free to agglutinate into a mass. The Beaufort black band
waa thus converted into malleable iron, though after a few ex-
perimental trials the operation was discontinued. The principal
objection to its extensive adoption, seems to lie in the difficulty
of effecting a complete separation of the extraneous metalloids
of the ore. In the blast furnace it is accomplished by mechani-
cal Bubsidation in the hearth, and the extraction of the metallic
iron &om the low level ; in the direct mode of manufacturing it
is effected to a certain degree, by severe manual labour, which
being skilled, commands a comparatively high price, and mate-
rially enhances the expenses incident to the process,

" The prolonged exposure of the metallic iron to the oxydiang
influence of the flame and gasei during the process of separation

Ptrom the alloyed matters, reaulU in a considerable wa^te of metal^
Hid accounts for the comparatively inferior yields.
" To obviate this loss, and to economize tlie fuel and labour de-
manded, the ground ore and carbonaceous matter have been aub-
jected to the necessary heat in a closed supplementary chamber,
whereby the combustion of the carbon is slowly tarried on at the
expense of the oxygen of the ore, but at a sufficiently low tem-
perature to avoid oxydizing the mass. From this chamber it is
drawn as required into the fiu;nace, balled up and shingled, the
deoxydizeil ore agglutinating without undergoing the puddling
process, whiph being essentially s decarburiziug process is nn-
jieoeasary with the minimum volume of carbon consumed in the
■deoxydation of the ore in the close chamber,

J " tJround carbonaceous ore may be substituted for the cur- .

I

ENGINEERIHG FACTS [Div, Vll.

■bouaoaous matter, auii laixed in the ue*!easary proportions with
same ore calcined, or, with raw hermanite, the ileoxydatLon
bo effected without the uauul ground coal, at a corresponding
reduction in tho expenee. lu this respect, the posGessiou of okb
' such varied character gives the iromuasteis of this country an
iportont advantage over their foreign compeers; and, should
mode of manulacture, at some future day, beootne more pro-
le than at present, would enable them to nuiiutoin their
ipretnacy in tlie trade. The rich carbonaceauB ores of Scotland
or Wales, mixed with the hematites of Lancasliire or West Cum-
berland, or other similar ores, reduced in suitably conatmcted
furuaces, may be converted into malleable iron, at costs conffldur-
ably under those incurred with the blast furnaces and subsequeut
decarburizing systezu.

" With exisling modes of operation, the advantages of direct
conversion are principally conhned to the comparatively small
capital required to estabhsh the mauufacturu, which may be on
the smaUest scale, yet, to a corresponding extent, profitable.
Hence it is especiaUy applicable to new districts^ requiring an
immediate small supply, and to countries deficient in the capital
necessary for carrying on operations on a large scale with blaet
furnaces, and attendant mfinicg and puddling furnaces. To
establish on a sound badis works consisting of blast furuocea,
Mfineries, puddling foiges, and rolling mills, a capital of at least
£20,000 per blast furnace, where there are four, is requirod;
with a fewer number, more. In the direct mode wrought iruii
in proportionately smaller quantity may be manufactured, with a
capital of only one-twentieth, or one-thirtieth of this sum. Jn
this respect, therefore, it is more advantageous, and may couse-
ifuently, under certain circumstances, merit the preference over
l^ie established system."

^ Proceeding now to the consideration of steel. Beginning with
the descriptive part of this manufiicture, wo camiot do better
than give the following interesting and valuable paper read belbru
the mechanical section of the British Association, by Mr. T.
Spencer : —

" The history of the manufacture of steel in this locality com-
mences at a vtry early period; for we iind that, probably 300
ago, a colony of Geimana seWXei t& a ■bW« an. liui tLvit,

■i.] MANUTACTUBE OF STEEL

w

^^^emeut, within a few milee of this town, mid, uccoriliiijj to tra-
dition, there (^tahlished this bmnch of local industry, where
they abo attained soraa celebrity as miLnufacturera of ewurds ami
Lilge tools, llie names of thcae JmiuigTantB who, it is stated,
tuok refine in this country, that Ihey might enjoy religious
liberty, wmv Olo, Moh), Vouz, &e., &<!., and some ol whose dtr-
^ceudania still reside iu the villnge where their ancestors origin'
ally settled, the names being now Anglicised to Olei/, Mole, &c.
'I'lid name of this village is Shotlcy Bridge, and in the wall of aii
I'ld two-etoreyed dwelling-house, the original materials of which are
hidden under a coat of ' rough-cast,' there still exists a stone above
i.he doorway with an inscription in bad Gennan, to the following

rffect : DEa. HERREN. SKCBN. MACllET. REICH. OHN. ALLF. 80R0.

WAN. DVZVOLEICH. IS. DBISBM. STAND. TREVW. VND-LLEISIC. BIBT.

VND. DVEOT. WAS. DiR BELOHLEN. iBT 1691, of which the follow-
ing is a free translation, showing that the original importers of
the Bt«el manufacture t« the district were probably good Lutherans,
who liad suffered persecution for conscience sake : — ' The blessing
of the I/ird makes rich without care so long as you are indus-
trious in your vocation and do what is ordered you.'

" But tliere ia a much earlier record of these German immi-

^^ffrautd than tlie above ; the parish register at Ebchester church

^BtaDtaining the following entry, by which it will he seen that tlie

^^■KiB even then had undergone a c)iai>ge :—'' Elliner, the daughter

^^H Mathius Wrightson Oley, was baptized on the 17th day of

l^^ane, 1628;' and shows, also, that tiie grandfather of the child

then baptized had probably married into a family of the name of

Wriglitson, at that time resident in the neigh Ixiurhood, aa appears

by several entries in the pariah regiister of the period, clearly

marking a third generation.

" In all probability the next works of this nature established
in this locality were those of Sir Ambrose Crowley, who is de-
' us an ironmonger, and afterwards Aldernian and Lord
pKyoT of the City of London, and who appears to have cora-
" 1 manufactory at Winlaton Mill in the year 1691. The
mes of Landells and Chambers are mentioned as heing in this
an early period, after whom came Cookson, Spencer, and
Uiers, whose works are carried on at the present time.
L." The inaDuiactiire of steel, as at present carried ou in this

««

ENGINEERING FACTS. fDiv, YII.

^K liisti'ict, comprisea the foUowiiig descriptions: — Blistered, Glieur,
^^L spring, and cast steel, to produce which the following matetiala
^^B are required: iron, carbon in the shape of cborcool, manganese,
^V coal, cuke, tire-bricks, and fire-clay — of these the iron and maa'
ganese are imparted into the district, the former fur the beit
qualities of steel being brought from Sweden, The charcoal, nul,
cuke, fire-bricks, anil fire-clay ate produced in alniost inexhaustible
quantities and pf most excellent quality in the immediate neigh-
bourhood ; a small proportion of fire-clay, however, having (o b«
brought from a distance for admixture with that found in tha
Imality.

" I'Lie mode of mauufnctun; iu use here is that known at the
cumenting or converting process, the furnaces used being large
enough to contain from 10 to about 23 tons of materiala at OM
time; thi? material consists of selected irun, and kni
uianufa/:turer as being most suitable for the purpose for whieb,
it is ultimately intended. It is placed in the cells of the fuman
with bruised charcoal in alternate strata, the whole being corerad
with a vitreous material to effectually exclude the air, and belt
is applied for a period of about eight or ten days, according ta
the degree of carbonization required. Tlie mass is allowed to
' cool for several days, and the haca are then taken out in the fotm
I of blistered steeL The change that has taken pli
I ture since it was placed in the converting furnace is very maijw^
I for instead of now being of a fibrous nature it is quite of a crjS'
talline chui-.ioter, and it must be reduced or drawn out under iciQa
I or heavy hammers to bring hack to it something of its former
I nature. It is, however, used in the blistered state for nuDf
I purposes, such as for welding into hammer faces, and for wel<"
to iron for edge tools and for spades and shovels, although
steel is now fast superseding its use even for these ptnposea
Spring steel is made by simply reducing with rolls the blistend
boM, and shear steel is made by repeatedly drawing down U)d
welding the blistered bars. This last-mentioned descriptit
- also being fast superseded since the introduction of mill welding
Spsiist steeL

" The most important of what may be termed the secondaiy
m processes of this manufacture is that for producing cast steel,
ytand it is (among the old methods of wuikiiig steel) of the ijgrt

intriKluctinn. Coat stoel is ditFi-rent from all tlie olhur
nnptitins of steol in its fineneas of grain, greater Btnsiigtli, ami
iliomt^neity, The first steel nised in tlit^ country partaking
Ul of tbe nature of this description of steel was the Itiiliiin
[, wliich vae much prized by users of steel, especiully liy
It makers of dies for coining presaes, who, it is faid, paid tiiv
twt fabulous price of five gQtuww per ponad fir it. Tlie dis-
Iteiy of the Englisii method of making cast atutl is diiu t-i
■ijainin Hnntsman, of AttercUfTe, who appears to have airived
~t by a series of experiments. He was a clockmaker, and
1 to improve the quality of steel for clock-springs. Ho
■ bum in some part of Lincolnshire in the year 1704 ; find,
igh his family are said to have been Oermfiu, he must bnve
) thoroughly Anglicised, as he was a strict Quaker. In
■probability, this discovery was made before tbe year 1760,
t had become pnbhc previous to bis death, which took place
h776, at 72 years of age. ITiis process was first introduced
I this locality by the late finn of Messrs, Crowley, Milling-
)f and Co., in tbe beginning of tbe present century, probably
it the year 1810, who were next followed by Messrs. Spencer,
PTewbum. Afterwards, Messrs. Cookson and Ca erected
melting furnaces, at their works at Derwenteote ; and
Q the last few years, Massra. Fulthorpe and Co, of Duustou,
i.ommencei.1 this branch of the steel trade. Cast steel is pro-
duced by breaking tbe blistered steel into small pieces, and
]jlacing the same in crucibles or melting pots, capable of contain-
ing 36 to 40 lb. weight each, two of which are placed in each
melting furnace. A plentiful supply of coke is now filled into
the furnaces, and by the aid of a strong draught of air, an in-
tense white beat is obtained and kept up fur three or four bout's,
according to the nature of the steel required, Wlien it is ascer-
liiined that the steel is perfectly melted, the crucibles are taken
out and their contents poured into iron moulds conveniently
placed near, and left to stand until in a cool enough state to be
taken out as cast-steel ingots. These ingots are afterwards re-
h'.'ated and bammered or rolled, or it may be both hammered
and rolled, according to the description of article for whicb it if
intended to be used. To produce lai^e ingots, a number of
crucibles containing liquid steel are brought out of tbe fui-uace.i,

ENfllNEEUING FAfTS,

[Orv. Vlt I

quickly following aacb ulliur, aa<l a. coDtinuous stream is kii)>J
flowing into the raould. There is scareely a limit to the S
ingiit that may be inaiie in this way, aa was evidenced by Iha
monster block of steel exiiibited by Knipp, of Essen, nt Ibe In- J
teruational Exhibition, in London, last year; but great n?^ |
are run of getting an uusound ingot, as the least delay in g<^ttiiig
out every craciblo of steel in perimt order might c
tion of the stream, and thus make an unsound casting, bi tlia
year 1839, a great improvement was made in cast steel by J
Heath, by the introduction of manganese. Having describe
the various processes that the several different kinds of elM
nndei^ in its manufacture, it may be useful to notice some
the new methods that have been tried iu the neighbourhood.

"The method of making ateel by the cementing or convortil]
process, as already described, may be called the indirect methoi
because the object of the process is to deprive, in the first il
stance, the pig iron of the whole of its carbon, making the p
duct as nearly as possible a pure malleable iron, and a '
imparting to it again the necessary quantity of carboQ to D
it into steel The new methods seem to aim, for the moat pu
at making steel by a dii-ect process, without depriving the p
iron of tiie whole of its carbon, and without reducing it into
malleable iron condition. This Lt effected by extracting a It
portion of carbon, but taking care to leave in a sufficient quftuti^
to make steel, the object being to save the great waste of ir
attending the puddling of iron, as well as tlie actual cost of thi
process. Of these last methods the Uchatius process is one %hi
was extensively experimented on a few years e^o at the Ifewbiii
Steel Works, and the following is a short description of the mat
ner in which the process wna carried un. Pig iron, of a fi
cloaa quality, was melted in a reverberatoty furuace, and run iut
a tank Jillrf with cold water, where it was reduced into grannln
this granulated coat iron was mixed with pulverised oxide of iroi
and some alkaline earths, and the whole put into the oidinnijt
steel melting crucibles, and then placed iu the furnaces. Id
which heat was applied in the usual way until it was broo^il
I a fluid stato. By this method it was thought that tita di
IB of hardness i>f the steel was capable of being regulated h
tiiB- u£ tiio granules, ^ud by IVie i^wmViVj at QSA>]£a uaodrVi*

Kr a gvent iinitibtir of experiuienls, at a cost of little under h
Busand pounds, on attempting to work it in lar;g« qaautities, it
B fbond that the product wns eo uncertain iu the qualities
kssATy to good steel, that the pioceae was altogether aban-
fc«L This irregnlarity of the produce was probably caused
I the uncertain quantity of carbon in the pig iron nsed.
rA method of malciiig 'puddled' steel baa been tried in thiii
Blity, but without euccess. Thia process was a patented iii'
Itiou of Rjepe, a German, and consists in puddling cast iron
la furnace constructed specially for the purpose, until it is
■BTved to be in the condition of steel Tliia state is found to
nt wben a particular form of bubble appears on the surt'aco of
I metal

P'The Beaaemtr process of making steel has also been inlh'-
Bed into the district at Tndho^ near Ferrjhill, but with Mbat
Keas the writer is not able to say. The operation, as is gener*
* known, conidats of blowing atmospheric air through a mass
kelled cast iron until tbe carbon and the whole of the inipuri-

■ (rf the iron are burnt out of it. This, process has been so
m deambed by Mr. Beaaemer himfielf, at the meeling of the
■ish Association, at Cbeltenhaoi, that it is unnecessary to give
■tailed description of it liere ; but it may hn meiitinned, that
^eonmtenced by extracting only a portion of the carbon, in-
Uiiig to leave in a sufficient quantity to produce steel, but the
■calty of adjusting the exact amount linally led him to ex-
fat the whole, and afterwards restore the exact quantity rcqui-

■ )qr adding a measured amount of highly carbonized cast iron.
Beriments in making cast steel from the ^araimtd sand from
Mr Zealand, and also from another similar sand from the coast
Htaly, have been tried at I^ewbnm with a resi)lt of getting
Lsxcdient quantity of steel ; but, although yieldipg about 51

■ cent of metal, the cost of its production, without including
vthiuE^ for tbe sand, was so great that it woijld pot answer
SninereiftUy. It may be meutioneii that thja description of
Halite sand appears to possess the remarkable property of not
BOtning oxidized when kept in a moist condition; and the
iter wonld call the special attention of chemists and metal-
Wsts to the fact, with tbe view of aniving at (what would be
I invaluable discoveij) the production of iron or steel that

388

ENGINEERING FACTS.

[Drv, VII.

»

would not Im subject to the destrojing action of the uxj-gun uf
the atnioapliere.

"The articles mauufactiired from eteel in this locality n
vtiry numertmit, amoogst which may be mentioned railway taim,
tyres and springs, piston rods, motion bars and files for eu
!, rings for Ekkeley guns, shot, Sec, the great bulk 0!
tonnage being railway springs of various kinda ; buffing, beariug,
and traction in the iaJninated form, as well as the volute spring
originally maiiu in tiiis country at Newborn, and of which there
have been many huudreds of thousands mado the last few yean.
The rings supplied for guns made in this district have bi?«n pio
nounced by the oonsumera superior to any others. A liiTn, il
this locahty, has been apxiointod makers of springe for ill, 10
Bridges Adams' patent for the application of circular spriug* faJ
tween the tyre and the frame wheel for all kinda of rolling stod
n railways j and it is stated that spring applied in tliis maBH
i'ect an increased durabiUty in Staffordshire tyres of 60 H
cent, over Krupp's cast-steel tyres without the springs. j

"The estimated a^jpual value of the steel manufactures of U
district is about :£100,000, giving employment, at the ptCMj
time, to about 300 persons, and consuming annually about 15,0fl
- tons of coals. There are in the district nine converting fill

3es and 63 cast steel melting furnaces, of which the foUnritJ

a list of firms having those furnaces: — Messrs. John SpenM
aud Sons, ^ewbum, 6 converting and 36 melting fumooH
Messrs. Cookson and Co., Derwentcote, 1 converting and 6 mm
ing furnaces ; Messrs. Fawcus and Co., Swalwall, 2 convertiiM
anil 6 melting furnaces ; Messrs. Fulthorpe and Ca, DuoHtCH
uu converting and 6 melting furnaces. I

" Aa far as can be ascertained, it would appear that the nun
ber of persons employed in this trade in 1838 would be fM
70 to 80, and the weight of steel produced annually at tiM
time would be about one-ninth the quantity now produced. IS
prices of steel range from about £18 to Xll3 per ton, accordifll
to the description, the quality, and the size. This district'M
liigldy favourable for the development of the manufiudM^M
steel of the best quality, owing to the facility and cheapi^H^|
ivJtich a supply of iyod. can Vw; obtoiaed from Sweden-^^^^H

slow a

i.ft4.

-kq\ Asa's

fcj

'fflnHtxv ifmsL

kand&nt supply of cheap iuel and labiiur in the neigh boarliocl.
I busiiieas require^ however, the most vigilant attention '>!'
ighly practical nnd experienced persons in its managenii'iit
'q anj considerable amount nf succe^*."
•The Germans seum to I>e fur ahead of us iu priKluoing steel in
as the blocks sent to the 1862 luteiiinlioiial £.\hi-
i fully illustrated. OwiwR to the system of melting cast
il in crucibles considerable difficulty and danger attended the
Baling' of their contents in regular and quick Buccesnon bo as
a sound and homogauoous casting. Each crucible was
n weight, not being able to contain more tbau 100 lie.
i, and this required two men to handle it. The following is nn
ptract from an article translated by the ' Pmeiieal Meekanicn'

li' from the 'Kolmiseho Zeitung;' —
r The first manufactory of cast steel was established in Sheffield,
' s year 1740, by Hunteman; and, till this century, he had
I snccessful followers, except in England. The exorbitantly
■a of steel was, meanwhile, a strong inducement to attempt
PTproduction elsewhere. Gei^nany was not behind hand, ami
B hEHi the happinese of posaeBfiing men, who iii)t only imported
lliB English mode of manufacture lo their own land, but, by im-
provements and new inventions, raised it to such a height that,
in the present day, the German manufacture of cast steel stir-
|)iL3se3 that of all other countries. England siicceedeil in pro-
ducing cast steel of such superior quality, that, itt this I'cspcet,
no material advance has been made upon it ; but the size of the
individual pieces, which the manufactory furnished, was so small,
that, necessarily, only tools, weapons, and fine articles of ail kinds,
were made of cast steeL There appeared, in the London Exhi-
bition of 1861, a block of cast steel of almost 5,000 lbs. weight,
exiiibited by Herr Krupp, of Essen. The astonishment which
it produced was general and great ; it could not have been greater
ita<l a skilfully cut diamond, of a pound weight; been pro<luced;
and such a gem would have been of much less importance, for,
to the existence of a block of cast steel of several thousand puuiiik
weight, was attached the pos-sibUity that this strong material
might no longer be limited merely to the fabrication of chisels,
d files, and utiiev small articles, but could be used for machinery,
the construction of railroads and carriages. Tliat block

I

i

288 ENGINEERING FACTS, [Div. XO.

upeiied B. new career to cost steel, while it proved that no limit
t'l its size ezidted, save in the extension of the furnace and V '
plant; and that this limit can be widely stretched, Here £i
demonstrates by the block of 40,000 lbs. weight Bent to tlia
present Exhibition.

" In the English factories, aa well as in Kmpp'a foHndiy, taHj
blocks of the most simple form were, and are still, produced, till
steel melted being poured into cast iron moulds. These bloeki
acquire, in process of working, the same character as fiuiahed bu
(fertigen luppen) in the manufacture of iron, which can onljr bi
enlarged by the welding on of other pieces, and, like these btf
of iron, the simple steel blocks are fashioned into objects of vaij
ing form and size, by hammers. Toilers, and other mechaniea
means. This kind of eteel manufacture has been marvellondj
improved in Krupp's work. He has gained for himself the donhb
merit of producing in his melting works, steel blocks of the h
quality, and of every desirable weight, and of afterwards fi
ing thera in liis fnrges, and meehanica! workshops, into objeo
which none before him had ever made of cast steeL In additiv
to many other things, Krupp has furnished cast steel axles fi
marine engines, locomotives, and rail-earriages, and cannon, ftoi
the lightest to the heaviest calibre. Even a square si
is iashioned by mechanical means into a round wheel-tire of on
piece, and without being welded. All that can he made from I
simple steel block, by the agency of mighty hammers, and ti
ing, boring, and planing, is executed by Krupp with a skill a
yet unsurpassed.

" By this method of fabrication, those properties of cast etee^
which it possesses in common with malleable iron, are tamed to
the best advantage ; but the other qualities found combined In
it — its fusibility, and capacity for eaatitig, are not fully hro
forward. Perhaps many a reader has already remarked tfajsj and
inquired, with surprise, why only simple blocks are cast from V
molten steel, and not, as with c^t iron, all tlioae objects wfaid
owing to their complicated form, are forged with difficulty. I
is, apparently, quite aa simple to employ cast ateel in the Ban
manner as cast iron; and the great advantages to be gained h
so doing lead to the presumption that attempts have not bM
wanting, since the firet cisV, rf nwVten. ■Ajs^'^caa a»«v-, hat ll

^iS^^^^^^^^^mm

atb9iup<;i< were Ii>n;^ unsuccMsfuL N<} cast forma, propertj no-
called, cnulil be ubtaiued from ateel by oay of tlie nipUiixLa ti
use, with otliar niL-lak A new discovery al-jiie could reach
the goal

" Of all who strove with this aim, one only was suceeufal :
Uerr Jacob Mayer, the faunder of the Bochma Steel Manufactory,
and the present g«jentitic director of these works, for the maau-
^ture of cast steeL

" With the untiring perseverance of years, and the euetgi-tic
hitb of a man who is urged forward by the coii^ciousnesa Unit
f will at last overcome all difficulties, Htrr Mayer baa com-
)«ted bis ta«k, and discovered tbe method aud way to make,
i steel, true castings, answering evoiy purpose. Thus an im-
erviee has been rendered to science, for now only is it
iBible to profit, in an edieient manner, by the great advantages
hicb cast steel unites in its double nature. Many obji.«ts which
prove too weak when made of cast iron, and which are very ex-
pensive, and, perhaps, still defective when made of welded steel,
II ar malleable iron, can be cast directly from steel, in consequence
^^tf Bstt Mttyer's discovery, and are not to be surpassed in ezG«l-
^^bce. Ag^, things which are first ca^ can be subsequently
^^Kepaxed by hammers and rollers. While, fur irun, casting and
^Vbrging are two completely separated regions, Herr Mayer has,
'' for cast steel, thrown down the partition wail, and summoned the
former to the assistance of the hammer aiici roller. Of course,
steel casting has narrower limits than iron casting. Tbe extra-
ordinarily high fusing temperature of cast st«el, and its imperfect
liquidity when melted, hinder the casting of as fine objects irom
steel as from iron. The boundary may be somewhat enlarged,
but cannot be entirely removed It is, however, practically, of
little importance, and is no hindrance to the employment of caat
steel for many useful purposes. Some specimens, forwarded by
I tlie Eochum Company, to the London Exhibition, deserve espe-
^hmI notice ; and we must be allowed to speak of them la parti-
^^■olar. Belative, however, to the peculiar manipulation of these
^^■tstings, nothing can be communicated, for this is the secret of
^^Ke Bochum Foundry.

^^K " Church bells were the first castings which Herr Mt^er at-
^^Kinpted with his new method. When these were first exhibited

■ I

I
I

I

eoo E>T01NEEKING FACTS. [Dur. VR

ill Pai-is, in 1855flht-in motto, ' May their firat chiaios be peaot^'
WHS ni>t fulfilled, font TiolentcaMroversy mom about tiia mab^H
itself; and the quBstion, whetlier they wore stoel or cast imi\
divided the men of the department into two hoBtile factions, i
Mighty authority (ruled by the thought, I am, t/ie me-nufaeivaei
iif steel) would not allow tbat they could be cast steel bells; ha
Hert Mayet iuoontestably proved that tliey were so by breakiiiij
one of thsm. The jury awarded the lart^ gold Dieda! of honoia
to the Bucbum Compaiiyj opposition was silenced; friends ao
knowledged; and adversaries could not gainsay, tiat the diseov
eret of eteel had a formidable pival in his territory. Since then,
many handred steel bells baye been cast. Tbe advantages whuA
the new bells possess over the olit (which do not siupass them
in cleamoas, or loudness of tone) are greater durability and sbrengthy
with nearly the same size and form; and well nigli half the ex
pense. This last cirenrastance has enabled- many jioor churches
to rejoice in the chime of a bell. The Buchum Company esliibit
in London a ateel bell of 8^ feet in diameter, and nearly 20,00(
Iba. weight ' Let her name be Concordia.'

" The nest important application of Herr Mayer was in favoui
of railways. The wheels of rail- carriages and loconLotivea, litn
those of common mads, are secured with a tyre, only neoesaaril;
much stronger. They are usnnlly 2 inches thick, and 5 or I
inches broad, and have, in order to prevent their running off thi
rails, a flange on one side — »pih-kranz. Formei'ly, wlieel tyrai
were conHtruoted of iron or pnddled steel Both these matervib
permitted no other modfl of fabrieation than bending into the
wheel tyres, a Btraight bar forged for tbe pwrpoae, tbe ends i>f I
which were finally welded togrtlieft Tlie weld is the weak poiutv
of the tyre, and, on account of bhe great danger connecteiH
with it'* fracture, hua absorbed much attention. Tyres, withoii^|
a weld, were long the desideratum of railway constructors. Hei^H
Kropp was the Jirst who ^tilled their wislies, and furnished tutJ^I
wElded tyres of cast steel — the best raateri^ for the purpose iii^|
existence. His method of manufacturo, so fer as it is known, ^^t
ns follows i^First, a long flftt bloek is cast; this is lmmntue^|
out ; a long, slot-like hole is pierced along throiigli the middli^|
and, by wedges, it is gradually estended, while liot, into a ni^^H
mid, hstlf, it is made round on a. l^s,n.^TO.\ -mVW ieenfrirm^j^M

s.] CAST STEEL -n'ltES FOR WHEELS.

^^nssed tlirough it. Inateail of this difficult metliod, auother is
employed in the Bocbiioi works, l^jt wliicb the production of
>^t(!el tyrba is much simplified. Tiie dtscofpiy of Herr Un3'er
ri'uders it possible to cast the tyre witb the Saiige npon it; tfai.4.
like every otliei ca.stiiig, mast be freed from the mould; in tliid
^late, it biis only balf tbe finished diameter, and is euliLrged by thi;
f^tretchiiig it undergoes between the central roUcca; these niv
■ lriv«n by a nearly 300 horse-power engine at Bochum. Tliis
Iliebuni method of wheel-tjre manufacture is a fiiir example nf
tin; extent to wbicb tba preparation of steel can be facilitate!.! by
liie preliminary operatirin of casting ; in fact, casting and furgiii;,-
.-.Ijould go hand in band. Ou tbe German railroads, thoosands
MJ' Eoclmm tyres am already in use, and highly approved of.
Among those sent to tbe London Exhibition, is one of tlie uii-
ii:jUaUy large diameter of 9^ feet, and another, which has been
bent close double in tbe cold state, to show tbe toughnf>.ss of the
material As east ateel tyres (on account of their great durability,
iiud consequent less wear and tear) are of the greatest importance
to the raUway interest, the companies have much reason to thank
tbe Bocbum Company, since, by their method of production the
|M'ice bas been reduced by one half,

" To scomre the tyre on the wheel frame, tbe contraction, con-
sequent on the cooling of the tyre applied while reii hot, is made
iide of; tension ensues, and the strength of tbe wheel depends
on tbe cam witb which the fitting is adjnsted. This initial strain
i-xpoaes tbe tyre, under certain circnmstances of temperature, ti'
the danger of bursting. Tbe tyre is also rendered thinner by
tbe wear of tbe brake, and continued rolling in use, expands
uiid looaena the tyre irom. the wheel. These avils might be
^'^ iated, and cast steel wheels brought to the highest perfection,
they could be faahioned in a aiugle piece. In any case, this
b very difficult task for the founder, and, till recently, no steel
t was ever changed by tbe hammer into a wbeeL But tbe
mtor of castings in steel bas succeeded in casting, by his own
1, a railroad wheel, in which the tyte, spokes, and nave,
^e piece. This oast steel wheel is tlie best of alt
B yet invented for railway carriages, and it would be ditti-
: to snrpnss it. It is (if not in first cost, at least in u»i!)
r than ordinary wheels, provided with steel tyres ; and it

ENGINEEBINO rACTS. [Div

rsna
lia-^ llie grfliit advantage of being strong, light, and needing no
rejjairs. The Bochum wheel ia exclusively the work of sted
ciiiiting, and neither hammer nor roller is u»ed in its fabricalian
"When taken from the mould, and freed from the sand. It ia care-
fully annealed for the removal of any internal strains (apannnn^
due to conlractioD, and then completed with the assistance of
the boriug and turning lathes. In the spring of 1860, the
Boclium Company first came publicly forwani, and proved by
ciimprehenaive experiments, in the presence of a. large assembly
uf railway contractors, the advantages and superior strength <n,
this new manufacture, which soon became exteasively employed
on the Glerman railvrays. In an International EKliibition, this
invention appears in London, now, for the lirat time. The Bochum
Company ha." sent thither two cast steel asles, with wheels at-
tached ; one pair of wheels ia juat as it would be fumiahed ta
the railroad ; but the other is turned and polished, and show%
by its unblemished surface, how coripletely Herr Mayer has
overcome the dif&culties of moulding in steel, and succeeded in priH
^ ducing a clean and solid casting. Besides these carriage wheek^
^k there are two locomotive driving wheels exhibited, in which tkA
^^ bosses fur the shaft and crank pin have hoea also cast ; steet
^1 wheels, for locomotive tenders, have been in use for some tim^
^M aud have surpassed all expectattuna. It has been the fate c^
^H many a German invention to meet with its first honours in. ■
^H foreign land, or to be plundered by strangers; but a happiet
^H destiny ia allotted to steel costing. The Bochum Company hu
^H the means ai keeping the invention on German ground, and eu-
^H nbltng it to take roo^ aud come to perfection, on the spot whera
^H it first saw the light. Their great foundry, in which every kind!
^B of cast steel is manufactured, has nndertaken, as its principal
^H biisineaa, the supply uf articles for the railroad trade. In addi-
^H tion to these articles, the Bochum Company has furnished cart
^^H steel axles, and springs fur locomotives, and railway carri^ea,
^^H of anperior excellence. Its extensive workshops are furnished
^^B fvith the best tools and furnace apparatus ; anil, by their aid, and
^^H the toil of upwards of a thousand men, aa much as 40.000 Iba
^^H nf cast steel are daily pioduced and manufactured.
^^H " Amid the treasures and splendour of the London Exhibi&)%
^^■£/ie cojjtri billions uf German aXxtA ^iNut \i«a\sliY maDy TJio^ta

TaoN.] STEEL CASTINGS. 2»5

scarcely remarkeJ ; auil yet they are of great i[ii]>ortaiice, aii-l

l-uiot to one of the must remarkable advouctimenta of tlus agk;.

in the working of metals, TUia pnigress is more important,

::ausc it concerns steel, Ifte material jchicJt is ilestintii to tii/'ir

e place of iron, as the man spriutfs up /rum llie bin/.

" Great as is the prngreaa already ma'Jo ui Westphalia in stet-l

mn&cture, ShcifEielil will, we betievt', run tier hard in the race

r beginnicg ; and aided by the Beascmer proce«s, which, vie

EODgly aie of opiiiion, will in the end be foond f;reatly auperior

p the puddling one — for steel, at least ; we predict that we shull

t snrpaBS our German rivals in ntnguitude and fttcility uf pro-

f steel in great forged or uist masses ; and, we bopt^,

in superiority of quality.

'' Already, along the line of the Midlantl Bailway, at bctli
, where it passes thmrugh Sheffield, manufactories uf the
t class have sprang up, fur the prodaction uf heavy steel ;
lOBffit these, one of the most remarkable is that of Messrs.

a & Co., Atlas Works, who are engaged in the production

of soft iron armour plates by the rolling process, as well as steti.

They have two converting vessels, upon the Bessemer patent, at

work, each producing 4 tons of cast steel at each uperatittii ;

with the two, they can produce 24 tons of sttel a-doy, Mr,

Bessemer himself^ at his own works, upon a. somewhat less scale,

prodocea a large quantity ; and Messrs. Cammel & Co., Cyclops

Works, are at present constructing very large new works specially

~" r Bessemer cast steel, of the heaviest class. Nearly the whole

[ the steel now made by this process is subsequently forged

iito axles, shafts, cranks, gun moulds, etc

L " Sound steel castings, of finished objects, are, at present, not

tempted to be made, by pouring directly from the Bessemer

mverting vessel ; the mass of metal in this, as may naturally

B expected, appears to be hciuisoujte, more or less, end, probably,

'n act of evolving gases, that make it porous. But uni-

mity of chemical constitution of the metal, to the extent of

) large capacity of the converting vessels (say 4 tons in one

iss) is insured. This might be run into thin ingots, broken

J, and melted again, for steel castings, in crucibles, as by Krupp

ind Mayer, or in some still better and more fuel-and- labour

S9J ESGINEERING FACTS.

"All that is wanted, in iact, uow, to enable stucl castiugs to
B made quite as good, if not better than the German one^ of
any size, and at a greatly reduced price, is an air furnace,

leltiug the steel in large bulk, and without deterioration of
its quality."

Tlie Emperor of the French haa with considerable sngacil;

devoted large sums of money to the prodnction of a teverberat«ry

[ furnace, according to the invention and designs of M. Sudre,

I which is said to have been capable of fusing steel in large

I and thus giving facilities fur the production of heavy costings

The following is an abstract of a description of such furnace,
I wliich we quote from the ' Practical Mechanics' Joui-nal

" The methods of M. SuJre appear to have been devised as
uarly as 1857 or 1858, and have been patented in Great Britain,
as well as abroad; the date of the British patent being 3lBt
December, 1858, (No. 3007) sealed 29th May, 1859
munication to John Henry Johnston, London ; and rather more
than a year appears to have elapsed, belbre the inventor Boe-
ceeded in arresting the attention of his own Government, bo as
to be enabled to commence bis trials on a great scale in October,
1860. He had previously held a position upon the 'Chemin
dii fer du !Nord,' and made experimental researches on the fusion
of steel in its forges.

"M. Sudre'a discovery rests upon the combination of three
distinct inventions or applications, viz., a method of constnicting
a reverberatory furnace, producing, with pit cod, a heat sufficient
to melt cast steel, without destroying itself. A method of
misiiig the heat of this furnace, by preliminarily iieaUog the
eteel to be melted, near to its fusing temperature, without injury
to its quality ; and a method of protecting the steel,
"a placed in the reverberatory furnace, from all injurious action
of the gases, etc, passing above it, or otherwise, both before and
after its fusion upon the hearth of the furnace.

" The furnace was perfectly successful ; but experience
use, and some suggestions due to the acuteness and sciei
M. Sainte Claire Deville, developed some points in which it
miffht be improved. The second furnace differed from the former
:tioa^ and in aoma attwAMiaV Ck>^(K^te

^^"ball alludo hereafter. The furnace conaiata of tlio iuubI ^S^I
of hiii burs, sepurated by a bridge frum tbe hearth, ami that "
separated by a second aiid coutracted bridge, from an uveii. in
I w liich is placed a large niuiHe, or earLheii retort. The flame ti-ttu
s fuel passing over the first bridge, and deflected by the low
;b above in the nsuid way upon tbe hoUow of the hearth, passna
over the second bridge, envelops tlio luuffle, and finally pasaea
iB^ through a descending and borizoulal flue, u> the chimney
tftck — ft damper being interposed.

" The chimney stalk at Muutatain:, into which the fiirnaoe
Irew, was about 85 feet in liuight, 6 feet square inside at the
Ase, and 3 feet 8 inches square at top, and three or four pud-
ling furnaces aiRO worked into it, during these experiments.

" The draSti of M. 6udfe'« furnace, however, is not dependent
rliolly n|X)n the ascenaive piTwer of the stalk, and this conati
Utes one of its main peculiarities. It is supplied by a forued
^ut from a fan, delivered into the closed aah pit. The &n em-
loyed was about 33 inches diameter, and 14 inches breadth of
lade, and nut 1,200 to 1,500 icvolutiona per minute, Tim
font of the aah pit ^a closed by a plate, Temovable for the pur-
0Be of getting out tbe ashes, after one or more fusions. The
kearfh of the furnace is so formed that the steel, when in fusion,
B& be tapped out, through a lateral aperture, opening into the
ottom of the hearth, provided with a moveable iron shoot
incd with Are clay, hooked on to the peculiarly formed aide
W of the furnace mounting. This is stopped by a plug of
ipered infusible clay upon the end of the ordinary bott gtielc,
li as is commonly used for the like pur]ioso in iron foundry
npolas,

" Great care and precaution n
f the bottom of this hearth
tin nearly 1,800 pounds of li^ i
flos, etc

" It was formed of one mas. f y caref llj he t aiul tem-
pered clay, formed in place tip 1 y f dry sand,
Qorered with thin niillboaid on top, (which, when itduced to
'joiooal, was expected to leave perfect freeilom of contraction tc
le srfe of ■clay) the sand bed being laid oo courses of bricks on
Tim ^isleoal fot the eolfi was formed of oue-fouilJi

mpl

^ d

tl

foiTuation

p

tv

^tas

,1 at to con-

tuel, ith

Hi

t room for

I

ENGINEEKING FACTS. [Drr. VII.

tempered infiisilite cla? of AndemKt^ irorkeiJ up with great care,
with tliree-fourthe of like clay pTeviouslj baked, and the masses
reduced to powder, and sifted to fragoieots of about one-eijg'Uth
inch in diomt^ter. The ohject of all this care was to prevent
the fluid steel from finding its way down below the sole of,
the hearth, en the latter being acted on by the protecting flux
employed.

" In the second furnace employed, these precautions were in
part neglected, and the sole was formed of fiic brick of the same
cby, but, as it pioved, with disadvantageoua icaults; and the
result of experience bos cuused M. Siidre to propose for hi« future <
fnmaces, soles formed by the potter, in each a single pieca of'
infusible clay, baked, Rud Liid into place on a bed of sand. The
first experimental niulHe was formed of fire brick, but this was ■

found to answer; aud a couple of earthen coal gaa retort^
laid side by side, and supportod ou pilaruts of bricks, so that ^<
draft circulated beneath as well as around them, were subati-
tutedi these answered tolerably, though not sufficiently infudibley,
&nd found liable to crauk, and so to !ut ia ail to oxidise the steel
withia

H. Sudre in bis last furnace employed snch retorts; laid
npon a eolid sole of lire cley, and ctiitted all over above, with a
(.■onsiderable thickness of the same, so that the flauie, <&c, only
layed above them.
" In this furnace, too, he remedied some other iuconTenience*
found iu the firat. Thus, for the fire clay plugn {ohfurateursi ift

frames, with which the apertures of the first furnace wok '
dosed, and which were fnuud to expand and stick fast, and even
to get soldered into their places — he substituted the ordinary
Blab of fire tile in a balanced sliding vertical frame, as usual in
-puddling furnaces, aud the two bridges were made hollow, the
air spaces through each passing right out through each of the
side walls of the furnace, bo that any cracking or escape of steel
here, could be at once seen, and gutuded against by ramming in
dry sand into the air spacer.

The main other diiference of this second furnace from the
, consists in the lengthening the whole considerably. This

due to M. Sairite Claij* Deville, who remarked with the

that the point, of gi^ateab \iiaA wm ^soci^ *£««

l«oK.] aUDFE'S FUKSACES FOR STTEL. 2W

hrii]ge. It is indeed obvious, that a reverbenitory furnace with

a forced drail, must have this point ' In coup de fluilnwaa '
thrown further forward beyond tlie biidge, as the draft i*
stronger.

" The dimenaiona of every part of these furnaces, the apeciiil
precautions adopted by liim in every detail, the results obtuined,
K-ven the accidents and mistakes and tentatives through whiuh
this, like every other great improvement, has passed, are minutely
recorded by M. Sudre, with honesty and intelligence, in his vahi-
able moraoir; but, to the original, we must refer those wlio take
a direct interest in the subject, as occupying too much space here
to transcribe.

"We pass therefore to some explanations of the principles
upon which his methods are based. It has been known since
the researcbea of Dr. Robinson's (of Armagh) early years, to be
found in the Transactions of the Royal Irish Academy, that as
high a heat can be produeed by a draft furnace, as by one urged
by blast ; that the only difference as regards the mitzimum tem-
perature attainable, ia one of time. The blast funiace arrives
within a few minutes, at a temperature that the drall or wind
furuace may take hours or days to attain. But upon tbis ques-
tion of time dejiends, cceteru panbaa, that of the endumcce of
the fornace itself; whether, in fact, if the heat be snflicient, the
matter exposed within the furnace be alone melted, or witli it,
or before it, the furnace itself be melted down.

" It was by proving and taking advantage of this truth, that
Dr. Robinson was able, quite thirty years ago, to fuse platina in
a small blast furnace, using as fuel the pure haril anthracite of
the Kilkenny coal fii^ld; and with which he attained a tempera-
ture that ceriaiuly has never since been exceeded witli any solid
fiteL It is true that, as Dr. Wollaston (who was present at some
of these trials) showed, the magnesia of the crucible acted
slightly on the platina, to produce an alloy more fusible than
pure platina itself

"This then is the first object of M. Sudre's ingenious com-
bination. Ey applying forced blast to an air furnace with the
reverberatory hearth, he is enabled, after bringing up by air
draft oitli/, the heat of the whole furnace as high oa its materials
wiU aaiaif' bear, then, at the right momeat, by converting Uw

ENGINEERING FACTS. [Div, V\l,

niiturai draft into a forced blast, he can withiti the fiiortest [kw-
sible time — and therefore with the least possible injury by inelt-
ii;g uf his furnace — bring it up to the exfcremity of beat necea-
sary to bring the steel into fusion. But furthnr, the steel itaclf
uust be hri'>ught to such s. preliminary state of high temperature^
that it shali offer the uainimuia of lesiiitiuice to the fusing power
of the furuace thus urged to its highest point ; in other woidf^
Cold steei must not be put into the hearth of the furnace, but
Bteel that has been already healed up to the highest point at
which it cau be handled with safety, and freedom from any seri-
s amount of oxydation during Uie momenta rf transfer. With
is view, he employs the waste heat of his furnace to heat the
ifQe, ill which close oven heated %.U around, but haFing n(
communication with the interior of the furnace, the cold steel ii
placed, surrounded more or less by grossly powdered charuool,
which deprives of oxygen any little air that may find entranut^
vhile the faggots or pieces are gradually aud thus safely, froin
chemical change, becoming heat«d up.

"£ttt the Steel tlius bruught tu a bright red or even yoUow
Ileal, when thrown into the hearth of the furnace to be fLaallj'
liquified, must still be protected from the evil effects of direotr
contact with the gases, &c, of the fueL The means by which
this ia effected, constitutes the third of the methods, which c
bined, constitute M. Sudre'e inventiou.

" "While certain biMlicates or silicates, such as those of the re-
linery heai-th for example, exerciae a. chemical solvent power of
amazing energy upon clay compounds, such as fire-brick, &e., it
is well known that neutral or basic silicates aw almost devoid
of any such power. Thus, glass of various constitutions may
be kept in a fused state for weeks, and at the high temperatun
of the glass house furnace, in the Stourbridge (or other like)
clay, melting pots, without any serious erosion <tf the latter tak-
ing place.

" These basic or neutral silicates (of earthy bases) have no a
tiou whatever upon metalhc iron or steel, at the fusing tempera-
ture of the latter, although they dissolve and take up whatever
oxide of iron may he adlierent to the surfaces of the metallic
masses exposed to them. In britf- then, M. Sudre fills, lo a
u poiiii, the hearth ol liia Iuiyi'M'" '*■\'C&\)^llVM\l,■«^su4 laoUJ

sO

SUDHE'S pnOCESS OF STEEL MARINO.

r Trith slag from blast furnaces sraelting iron with ckar-
M1 fuel, or fniliog the possesaiou at either of thetse, vith nbont
) parte fliiit or pnre siiioeous saiiil, 32 parla of liuM, and 1 2
) 16 parte of alumina (in"pe claj), and bring* these into perfect

" Inte ^13 bath of fluid glass, the pieces of steel, removed
iKth tongs from the muffle, and abeady heated to a j'ellnw heat,
are plnnged npon the hearth of the furnace. The steel heiiig of
higher density sinks to the bottom of the glass, bj wliiuh it is
thna conjpletely prevented from all chemical action of the gaees
of the furnace — while with nothing but a Btratum of an inch or
two of liqnid gliiss between, it ia freely exposed to ita heating
power. Within the liniitl of time, during which the steel is
here exposed, the silex of tho glaaa will no doubt have no per-
ceptible action upon it. "We may mention, however, that iron
exposed fur very long periods, in presence of common window
glass (crown glass,) becomes strongly siliciurctfeii. Tlie writer
fonnd, some years ago, that pieces broken or dropped off tliu
ends of the iron blow pipea in Mr. Coathiipe's works at BriBtuI.
and which hid remained for months in the bottiim of the glaas
pots, were converted into globnlar masses, harder than any file,
a high silvery metallic lustre, and upon analysis proved to
IQtain a definite compound of silicon and iron.
"To each 1,000 pounds of steel he finds it necesaory to have
lout 700 pounds of hquid glass upon the sole of the hearth
r complete protection. The glass gets partially devitrified,
'n a single fusion, but, as in Paris, the price of broken wine
I is only about twenty shiUing per ton, a new supply is not
plargc item in the ejipense of the procesa
" French bottle glass, like our own, differs much in com position,
iniplea approximate to the formula.

KO 4

3 Ca O + 2 A 1 , 0, + Ffi, 0, + S s;, 0,.

Our English bottle glass is fi'eqnently made with cnide soda, or
with Glauber's salts, from the salt cake works, in pari, at least,
^■nd so may not be free from sulphur compoirnds, which might
^■pjuriously act upon the ateeL M. Sudre gives his own prefer-
^Hpoe to the French bottle glass, hut has also employed with Buccess,
^Hm slag from the high fuiuaceB of Iha Couviu iron wotlu^ ia

KKBO ESGISEERING FACTS, ptv, Vtl.

ISolgimn, the iron of which, produced by charcoal, is justly ccle-
linited. The coal which he actually employed in his experiment^
mid of which lie appears to have burnt in all aomething like 50
toua, was of very inferior quulity, and very ashy,

»" He reniarka that the glass of the enveloping bath, aftei" tits
fUsioQ of the steel, had acquired certain hands and stripes of al-
ternate green and blue, which he says had some roBemblanee to
malachite and to ultmmarine, but it di>es not appear to hava
struck him that this blue baniliag, (like the intense bltte opaque
slags, sometimes met with in StafFordahiro, and which we havs
ourselves proved to be artificial ultramarine, accidentally formed
in the blast furnace), is no doubt duo to the actual preseiice here
of ultramarine ; and hearing in mind the nature of Guimet's pro-
cess for its manufacture, this affords absolute proof of the effective
protectiim which the liquid glass affords to the fluid steel beneath,
from the sulphur compounds floating above them.

" Theresultsnf IvLSndre's experiments at Montataire, have bean

to show iacontestably, that steel may he thus fused iu masaBS of

almoEt any magnitude, free from deterioratioD, and that his proceaB

is practicable in all respects, capable of being carried on, day by

day, iu a manufacturing manner, and with an economy far greater

. tlian ia poasibla in crucible operations, on equal weights of metal

" The consumption of coal, (of such quality as he had,) was

Vint 2 pounds for each pound of steel melted, and the total loss

' ■ ' in the process varied from about 8 down to less than S

ir cent Such preliminary trials, however, are no teat as to the

K^moant of loss, which must always, in sacb, be excessive. The

Tj'rocess, when systematized, would probably not reach 3 per oent.

n actual work.

"The steel employed for these experiments, (probably tot

Mnnray sake,) consisted, in great part, of old files broken np.

" These apparently, from the large amount of surfaue rust, and

■from the teeth being more iir less filled with minute particles of

brass and copper, or other metals perhaps, do not appear to have

given very good results, as to the quality of the steel after fusion into

large ingots. Puddled steel, however, both of French make, and

1 Ynstaljftra, in Sooth Wales, made from anthracite iron,

Rras also fused. And amongst the ingots obtained, pieces sent

«■]

BDDRE'S STEEL.

ktltir)' tools, and ttattd in various wuj-s, unil fouml W be uf rx-
■Uent quality.

" M. Sudre's results actuallj lead to a finauciul result, uf a tdii
E sWel melted at a total cost of about 58 frauia; bat we do
1 tliint it quite fair to fix uiwn thia, so candidly given by
s at all tho luinimuin to which his |irocess will eveutii-

" He thus suma up the comparative financial statement of liis
3 method, and of tho old one of cracible fusion. M. Siuln-'s
IS produces an economy of about two- sevenths the fuel, which
^ill, no doubt, hereafter be pushed still further.

" The coat of crucibles is whoUy got rid of, which amounts lo
yaat 30 francs per ton of «tcel.

*' The coat of keeping in n-pair the reverberator)' furnace is

an one-third that of the cracible wind ftimaces for

iqnal weights fused. Four-fifths of the manual labour emplnyed

I the crucible operations are saved — in the case of common

Bed oaiA steel ingots, viz., of from 50 to 100 pounds each; but

u the case of such gigantic ingots, as those prodnnod by Empp

by hia method of multiple pouring from erucihlcH, it is impoaaiblc

to say what saving may he effected — probably, more neatly nine-

_ tenths of the whole.

. " The outlay in plant for ftising equal weights in equal times
y this mode B estimated, by M. Sudre, as two-thirds less than
jtfa crucible furnaces.

" In. addition to these, as we believe, perfectly well eBtabliBheil
piBiiciBl lesults, we have the simplification and facdity of manu-
(Clinra, and the perfect BaJety of the workmen insured, as com-
i with crucible work.
" The form of the ingot moulds, adopted hy M. Sadre for his
mtfijaresliowninelevationandplanin figs. 8, 9, and 10 of
IT plat£ (not here given). Tlie latter was intended for gun moulfjs,
'■^at he shows good reasons for n>;andoning round, i. e., cylindrical
iiigots for every purpose, and adojpting those of the unequal aided
octagon instead. These reasons are related to the subsequent
process of hammering, and have been anticipated hy Nasmith,
"let. Clay, and others in this country. The method of pour-
T transferring the steel from the hearth of the furnace to the
onld, adopted hy M, Sudre^ consisted in tapping out the

I

.lip

302 ESQlNEEttlNG FACTS. [Div.

mi'tal, into a crime Imllc, lined vith more than usuallj refractor}
cluy, un<I previously strouglj heated.

" III the bottom, of the kdle was b bole, stopped hy & cc
plug or valve of baked clay, en the end of a vertical irou stem,
rilling above the eurface of the liquid eteel, hy raising which, tlia
jet of metal flowed vertically and directly into the ingot mould

" Tilts method, adled in Frauce, the ' ermlee & la quenouilU, i. t,
literally btf l/ie distaff, which the clay plug resembles, has tM«B
often employed in our iron foundries, and is that employed by H.
Eaisemer for pouring the steel made by his patent process.

" M. Sudre, wo observe^ claims, in his English patent, the m-
closivo right to the re-melting of steel mode by the Bessemer pnt
cess. Should the Bessemer steel ooDtiniui to improve inqoalit^
and in certainty of result, aa we fully anticijiate it will, probalilf
all great masses, such as gun moulds, &c., will be run directs fiwn
his converting vessels; and, in so far, M. Sitdre's process willbl
needless, but its value and importance, in re-melting steel, aitdiB
many future brandies of iron metallu)^, that aa yet only dinil]
show theraselvea in perspective, will not be superseded.

" Four to five hours, from first charging into the hearth, 11
found sufficient time to bring into perfect liquidity 600 or 81
kilogrammes of steel. When we recollect that the fiirnaoe w
fed with cold air, that the Goal was of bod i^uaUty, and that ihi
whole Bffaix was novel, and the brick work of the fumaoas ai
Hues, in all the latter experiments, soaked in wet, trava the over
flow of the Seine river in fiood, ws see that this short time can
still be greatly curtailed hereafter. The employment ot hoi blot
is provided fur by M. SuJre in liis specification, and its am
will, no doubt, greatly advance all the objects- of his method;
We believe he might also greatly improve bis method, or, at "
atill further exalt the tsrapemture, and reduce the time, of ftctios
of his furnace, by employing for fuel, at the last »tage of t"
process, pure anthracite coal of the hardest quality, =im!h as th
of Kilkenny, already brought into ignition in a separate fire plac^
and devising means by which it should he fed into the grat«
of the revei'beratory furnace, in mensured bulks, without eVB(
opening any aperture to the extemal air. For, although 'with
the fan blast, the rush of flame is ouliranle and cold air is not in.
(fOiJucet), the regimen of the flB-me at its yoint of maximam

i

■ten

] S0PKE'8 STEEL, APPLICATIONS OF. *»«

tensity ia thns, for the raiment of feeiiiug witli fresli fuel,

constant]; disturbed and the beat loMrenU. One iitimi^ijBe ii<l-

v^intiige of such anthracite as we above refer to, is also that it

jirocliices litemlty almost no elinkec to ahoke the bare — riuI

i the poiut in M. Sniire's indention which in practice wl'

I disposed to tliiiik will be the most truublesoroe, to fe«I one's

f to perfection witli.

'As this method becomes employed, it must give rige to a

land for fire bricks and moulded blocks, of various large sizeH

I forms, fur building these furnaces, of a far higher quality,

i much luoaj cefcaatery, than ajiything at present in the Eiig-

I fire brick market. In thes» we have mwih to learn from

many, where crucibles (tiegel), bricks, and all forms of tire

jJts, Sec, are made of a quality and iiifusiliility that we liii\e

yet attained to. M. Sudre well remarks, that the hiryar i\w.

BJ» of which his furnaces shall be built, tlie longer and beCti-r

f will stand the severe action of tlie fuel, &c. ; and he advises

t to be eaiplDyed, that shall not contain more thnn 3. per ceiik

Bhes,

' The staieiaents made by M. Sudre in this remarkable memoir
fully borne oat by the report of the tlireo Uoinmjssionera of
Emperor, who w»re ]hresent at sevecil n£ the experiuientH.
ij slate that it has been proved satisfactorily, that thus a ma^t
ipwards of two tons of steei may be fused, withont any injury
te qnalitiea, ojid with remarkable eeonoiny and facility. Two
I is yet a long way behind Kiupp's — ^20 tons ingot ; but there
lO reason why 20> or 50 tons should not be IJius nu^Ueil, in one
more furnaces.

' This invention nuist prniaoto powerfully the much-needeil
abolition of wrought iron in paddle shafts, cranks, screw sh.iftvi,
;. Why should not all our propeller screws, too, he now cast
steel at once, in place o£ making them of gun metal, at iiii
enormous cost, and to the dcstructinn by corrosion, of their own
necks, and of all the '\v*m of the ship around them.
The day, too, of wrought iron actillery ought soon to end ;
guns, all up probably to 32 pounders, may be cast, and
, and linished solid; but although M. Sadre's metliuda
he means of casting, aTid afterwards forging in (me mow,
ily larger thEiu even Krupp bus done, it will be

ENGINEERINQ FACTS. [Dn. TO

^B iiiii.4t unwise to turn back, from tliat ringed atructui'c with iiiitiiil
^^L teiiainn which aluiu: can give the luucimuui strength fi'um a giv«a
^H- weight of DieUl
^^P " Wlint theae im^niveiuenlB in steel point totvarilB, aa respucte
^^ iha heaviest claflsea of artiileiy, is this, that weJding, as well
wrought iron, with which it is iuseparalily oonnect«d, Bhonlii
iilandoned. That every separate piece and ring of a gun, wl

Annstroug or any other, nhmdd be piviluceii from the liquid

^^t\ in a single waited mtua, aud that thus, while oa the one bind
^^K| llie unct-Ttainty of welded unions is got rid of; we subatitute
^^B tlie change, for a material of about 30 tons breukiog weight, OM
^^M of from 70 to f*0 tons per square inch."
^H Much discussion exists upon the molecular eonatitution of etsd,
^H its true association with carbon being to a certain extent aCil
^H inisuuderstood. Many experiments have been instituted with
^^K view to settle this question, but the results obtained have almosl
^^1 lieen as inexplicable as the original subject it«el£ From the
^^M 'Chemical Neiw' we extract a number of experiments institutod
^H by M. Caron ;-
^^1 " Earaten observed that by the action of acids upon aofb steel,
^H a graphitic substance is obtained as a residue, wbicli is not li^
^^1 taiiied by the action of acids upon hardened steeL This i\A-
^^B stance he represented to be a definite carburate of iron FeC*'
^^B Berthier also stateil that cast steel contains another carburet, CF&
^^H " M. Caron* infers, from the results of numerous analyses, tiiat
^^B these carburets are probably mere variable mixtures of carbou
^H and iron, in which the iron is protected mechanically by the aa-
^H bon from the solvent action of the aciiL
^H " He has experimented upon et«el in three different voniti-

^H " 1. Steel as it comes &om the cementation chambers.

^^B " 2. The same ettsel hammered for o. long time.

^^P " 3. The same steel hardened.

^H "By the action of hydrochloric acid on theae three kinds of

^H steel, the quantities of graphitic residue obtained are very differ-

^H ent, being for 100 parts as follow: —

^^K * Camples- Rciuius, Ivi., iS.

BrO GABON'S EXFElElMKNTS OS HTEKL

F

^■ordinary steel . . I-S24=0'S2S 0GS7 O-IH

^■jCammend alcel . l'S4S=0'5eO 0'4JS S38

^^n'empered steel . 0-240 = tni«e. trace. 0210

^^Tliese reeults shnw that the effect produced hy t^raperiitg is
to some extent produced by liammering, and the qunlity of the
tteel appears to improve in proportion as the catbon is intimately
cumbiued with the iron.

" In tlie same manner forging, which improves the quality of
tleel, alfio reduces the quantity of carbon that is Eeparated by
solution in acids. Knlk-d aleel gives more graphite thau hani-
niered steel The influence of heat in this respect is the rererse
of that produced by hammering and tempering, and reheated
steel does not recover its primitive quality, or its chemical pro-
perties, as regards acids, until after it bas been hammered or
tempered.

" White pig iron presents the same variation in the quantity of
carbon that it contains in a free state, and tlie duration of the
annealing. However long thia may lost, them is still some car-
bon remains iincombined.f

" In the tempering of steel, the rapid cooling has a compress-
ing influence upon the metal, almost iiistantaneotis, and present
ing the closest analogy with the blow of a, hammer.

" A bar of steel rapidly heated to the temperature requisite
for tempering, and immediately plunged into C(dd water, under-
jgeut the following alterations of bulk ; —

■ Dimensions in centimdrea . j 1 '00 1 '03 1 '01

r ( I'OO 103 1-01

Voliimo ditto . 2000 21oa7 20'36I

"The effect produced by the tempering consists in a rapid
approxirantiun of the particles acting in every direction. It is
tliis concussion which M. Caron regiirds as prod\icing the com-
bination of the iron and carbon. The increase of temperature
has the effect of dilating the metal and giving to the molecules
a mobility necessary tu enable them to unite ; the sudden cool-
g bringing them rapidly together, causes combination.
*Abar of iron heated to bright redness was briskly ham-
f Compleg-IUndia, IvL, 211.

A k.

ENGIN'KERINO FACTS.

[li:v. m.

I

merod on an anvil jovered with liTitly-powdered carbon ; wlii^n
it had cunled ti> a dull red heat, it was suddenly plunged intti
lid water. Some parts of the bar were then found to hpe
been converted into steel at the surface, and resisted the file.
'T\ie same iron heated to redness, and cooled in the midst of chw-
thout being hunimered, did not present any tnioe of l»-
'ing converted into steel when tompeied in the same manner.
' Hammering does not effect so complete a combination M
pering, because it causes tiie concussion of the particles onlj
ine direction, while tlie sudden cooling in water causes tbni
iu every direction simultaneonsly. Moreover, the
temperature of the mutal after hammering tends to destroy the
combination, that has been effected by it. Oa the contrary, the
metal being quite cold after the ooncuaaion produced by plung-
ing it into water, no further reaction is pnasihie, except by heat-
ing the metal again.

" Reaumur* and Einman+ state that the volume of tempered
steel is l-48th greater than that of soft steel. £arsten,J on
contrary, snys that it is not ^uite certain that all ateel espanda
by tampering, and becomes of less density. In M. Caron's
pnrimeiits on this subject, he heated the ateel in earthen tubuH
filled with hydrogen. A bar of hammered ateel, 1 centimetre
square and 20 centimetrea long, was tempered, and found lo b«
reduced in length to the extent of half a. millimetro ; the other
diraenaions were inereasej 0*06 mm. ; the density waa rather
less than before, 7-796 in place of 7'817. These diiferences
being small, the experiment waa repeated several times with the
following results; —

100
1-00

" Heuce it appears that the reduction in the length of bar
after thirty temptriziga was nearly one-teuth, The dinunutiuli
in length waa not due to oxidation, and the sharpness of its edge*
waa retained almost entirely. The bar was then c'

' " L'Art de Oonvertir le Fer Forgi en Aciar," j
t Riuman, I., 220 to 228.

cleane^^H

fttt»iim«

9 Oir BTEII.-

yn

t density ftmnJ to be 7"743; eonsequeutly the voluran liml
ini;rea6e<i

" Similar experimBnta with a great number of bars of eteel j^avc
like results, and M. Caron concludia, that in tempering, uted
bura are reduced in length, while t)ie vidtli and thickiiese aug-
ment in the same [iroportiun a^ the density ia reductid

*' The opinion expressed by Kajsten, and the differences ob-
served in steel of different maimfactiire, induced M. Cawm to
I'liutiiiue his examination to drawn and sheet steel, witli the fol-
lowing results : —

Rauuil ilruwti hai steal

" These leeults, and those already give

V that ii

. Hammered steel bara are reduced in k-ngtli.
** 2. Eound bars partly hammered and piirtly drawn are aciircely
tered in length.
" 3. Plate-steel inoreasea both iu length and width.

. In a!l cases the density diminiahes — a result which agrees
nth M. Eegnault's observation, that soft steel is denser than

mpered steel
[ " It appears, therefore, that a bar of eteel may, in tempering,
Uge its dimenaions in a. different manner, according to the
"e of its manufacture. This accounts for the fact that alen-
ir articles, sucli as liles, become twisted ; this would naturally
result if, in for^ng, one side were more hammered than
e other. At the moment of immersion in water, the side that
I been moat hammered diminiahes in length more thau the

giving rise to the defect.

"The effect of the sudden cooling of steeJ in temiiering, may

ft compared iu other respects to the effect produced by the blow

^ ft hammer. Thus, the more sudden it is, the more consider-

e ia the correeponding force exercised, and the greater will be

B hardness. This may be inferred ttvia the following table,

ENGINEERING FACTS,

ropresentiriR the time of cooling of a, bar of steel, ani) the o
Bfioiidiug degrtea of temper produced iu the raet.il: —

*'iiiU temp, of tho liqun
Time of cooling
Ilogreo of t«iuper.
Shortening of tbe liar

alight. FL'iy Blight-
1-H7 1-173 !

" Tbe result of & great, many experiinenta with various liqniilft
—mercury, saline or acidulated solutions, water covered with of"
or containing in eilution mueilaginous or ajntp; eiibstaneea, oil,
&C, — appeared to indicate tli^t the liardneaa and otliet characters
produced by tempering are inversely proportionate to the squam
of the time of cooling.

"M, Deville* regards these resnlta aa accordant with thft
resnlta of liia observations on the rcinaTkable physical anil
chemical properties commanicated to substances by rapid cooling,
or, in other words, the excessive proportion of latent Iiaat, of,
heat of constitution, they retain when suddenly conled.

" Those observations showed that substances mighty in this i»^
speet, be divided into two very distinct classea

" One class comprises s-nlpliur, selenium, silicium — or rather
its compounds, silica and silicates— and tbe experiments of Ja^
quelain, Lavoisier, and Silliman justify tbe addition of carbon tO'
these. The other class includes lead, tin, bismuth, and probaUf
metals generally. The substances of tho former class ore 'snpe^
fusible,' and capable of being tempered, and acquiring the vitii
ous or amorphous condition. The substances belonging ta tin
second class present the same molecular condition after cooling;
either rapidly or aloWly, their density remaining constant,

"M. Deville considers that the results obtained by M. CtimL
may he explained by regarding iron and carbon as belonging p
spectively to tliese two different classes. Those results an
Karaten's show that iron and carbon combine at a high '
ture; that if the compound is allowed to cool slowly, the MB-
Btitueutfl cryatalliiM separately, the mass acquires a maximom
* CompUs-Reiiiua.Wv., W&.

CAROS'3 ExrERlUKSTS uK STEEU

bi&ity, and auid^ efiVct its sejmration into imn nnd a grapliiao
On the contrary, wlien the cuoliiig is sndJun, the
^1)011 remuins in a state of euperfuai»n, and conimaitiaites the
erty to Ibe campound utmtaiuiiig it in the soinii mniiner that
a conmiunicates this property to ollfiilies and metallic oxidtw.
"When the proportion of carbon is larger than in steel,
xiling gives white pig iron, and slow cooling grey pig iron.
>m this point of viuw, steel may be compared to glasa,
which becomeB divitrified when it is heated, or to sulphur, which
becomes CK^tahedral sulphur when heated to near 100° C. It is,
iiiiieed, worth inquiry whether in the tempering of steel, the
elfoct produced is not absolutely similar to that observed in tem-
pering sulphur; that is to say, the production of two distinct
layers, one superficial and very thin, the other intenial, and cor-
I'espondinf,' respectively to insoluble and soft sulphur,

" In any case, the sudden approximation of the molecules de-
termined by tempering, and compared by M. Caron to the etfeut
of hammering, maintains permanently a greater ilistance between
the molepulBs than their gradual appMximatioii bj ^low cooling.
" As regards heat of constitution, there is in such a case a in-
tention of a certain quantity of heat, which is, on the contrary,
disengaged daring slow cooling. This is the condition whith
M. Deville terms snperfuaion.

"In the ease of tlie different tinds of allotropic sulphur, it
a been possible to some extent to measure the quantity of heat
Erolved duiing tlie transformation of soft sulphur and insolulK^
Tphnr into octahedral snlphur. In the case of steel, the den-
and calorific capacity afford only indirect evidence of the
e of similar conditions.
"IL Deville considers that not only carbon is capable of oon-
in into white pig iron or steel, but that, in accordanw;
pitit the views above expi-essed, any of the electro-negative ele-
ments placed in tlie same condition as carbon would have that
tffeot. nitrogen he considers to be especially suited for tliis
purpose.
^^_- " A continuation of M. Caron'e researches on this subject re-
^Bktes to the function performed by manganese in the production
^^■t Bteel. £<>garditig it as e fact that all good steel is obtained
^^■M^wtiuc or Jjemutite oi-es hi;j\Ay Imyw^nttted wUU ciAte- ]

ENCfSEEHING FACTS.

[D...

w-

^B, gAueae, and assaniing that the presence of this metal is slniuit
^H e»«enti&l to the production of ati.'el, he lias endeavoured to nscer-
^H toiii the nature of its influence. Ho etntea lLa.t, bj means o[ i
^B auitable addition of metallic manganese, pig iron may be depriyvl
^H of the Bulphnr and Bilicium it contains, but that no influence is
^H exerci^d in the separation of phosphorus.
^H *■ The pig iron with which he experimented is described ttx of
^B Tory gooil quality, containing only traces of ailicium, and it vnis
^H melted by means of wood charcoal as free as possible from plioe-
^H phorus, sulphur, and silicium.

^1 "One portion of this pig iron was melted with a known qnau-
tity of iron phosphide; another portion, with iron aiilphide; and
a third, with iron filicide. The three kinds of iron th
tained were the subject of the experiments.

" Two equal quantities of the jihosphuretted iron were
n crucibles; in the one instance without any aildition,
[ other instance with 6 per cent, of metallic manganese.
I manganese used gave on analysis: —

1 -n )

'' The metal was kejit in fusion for one hour, and then poured

t. DuiTiig the operation the metal was slightly decarbonized

I by the oxidising action of atmospheric air. Analysis of these

two portions of iron gave the following per-eentoge results ;-

PliDsphu retted iron .
Xo. 1, Pliosphin^tted inm melted alone
No. i. Pliog]iburettod irou molted with fi per ot

inEttiganeau
Nd. 1. Melted agRin without addition
No, 2. Melted, again without addition
Na. 1. Melted a third time without ailditioti
No. i. Melted a third time without addition

PhoBphuretted iron melted with 10 per oi

retted it

nelted wilh 10 per H

"JSese reaults appear to inilica,\,B ^\\e,^ va i^&iwk^ '■^xvn.-^wc,;

} CARON-S KXPEBIKEKTS ON STEEL SI

. pig iron, manganese does not eSect thn separation of plii>i

Sulphuretted iron
y 1. Sulphuretted iron ineltrd alone
>. 2 Sulphuretted iron melted with S per c
muigtinese.

). 1. Melted agaia without addition
3. 3. Melted agaiD without addition
]. 1. Melted a. third timo „
3.8. Melted B third time „ ,,

Sulphuretted iron nielteit with 10 jH^r c

iroQ oxide ....

Sulphuretted iron nielled with 10 per c

iron oxide and 6 jior cent, niangaucso

These resulta show that, hy simpk fusion with acceaa of air,
effects the separation of 7-lOths of the sulphur iti tim
Repeated melting, without further addition of man-
ge, does not produce any considerable effect, and it appeurs
the proportion of manganese should be large, for by remeit-
the same metal with a fi«sh quantity of Diangaiieiie the sul-
may he almost entirely sepatated,

fiilicietted iron .... 0'99

I. Silidetted iron melted nlotte . O'SS

± Silidetted iron melted with 6 per cent, man-

Snese ..... 1-30 *77

ed again without addition . . 080

[o. 8. Melted again without mlditiou . I'Olt 3'DS

Silidetted iron melted with 1<J per cent, iron oxide 0-61
^ioietted iron melted with 10 per cent, iron oxide

and S per cent manganese O'ST 2'G2

Melted again with 10 per cent, iron oxide . 0'fi2

Melted again with ID per cent iron oxide . O'lS I'lO

'' The manganese used in these experiments contained siliuiiim,
id in this way, as well as by reducing the silica of the onicible,
Ided to the amount of siUcium in t[i^ iron, But this is not

9 case when the iron is decarbonized by the addition of irun

It may be inferred from these.: results, therefore, that man-
leee determines the separation of a laige portiou of the siliuiutn
lAn iron.
f" Xiu^eTaisuliB agree witli practical experience. The ores abuvu

I 512 ENGINEERIHO PACTS. [Div. VII.

meotioned, that yield the 'better kinds of steel, often contain
suliihor, but never contain phosphorus; and it is a noteworthy
f»ct that, although those ores coutain copper pyrites, the pig ii
they yield does not contain sulphur.

"Althongh TOangaaeae does not determine the conversion

iron into ateel, aa Karsten has well shown, it is nevertheless cet^

tain that — besides rendering steel capable of being welded — it

has an iufluence in improving the quulity of steeL M. Garon

considers that thid iifduence may be explained by the aid of iaetg

which he has formerly made known. When a aofficient quantity

of manganese is added to grey pig iron, the carbon of which is to a

great extent in a free atate, white pig iron is obtained, in which

the carbon is almost entirely in a 'state of combination. Tbs

effect is the same with steel ; a very small addition of mangtuiew

is sufBcient to retain the carbon in a state of combination, and,

J in consequence, to confer on the metil the characters peculiar to

■■good steel. However, the amount of manganese in steel

I not exceed 5-lOOOtha; more than that renders steel hard and

I brittle, the surface of fracture becoiaee cry^talliue, and the mebd

I is deficient in tenacity.

" It is a common practice in refining iron to mix ordinary pig
I iron with manganiferous pig iron, and the above results show that
I the beneficial effect of this practice is greater according to the
I Amount of manganese present. It appears, therefore, to be a
I point of practical interest to reduce manganiferous ores in sueh
manner as to obtain the largest possible amount of manganese
1 the pig iron. The spathic ore of the Siegen district
I from 15 to 20 parts manganese for 100 of iron; but the pig iron
made there does not contain more than 6 or 7 per cent, of man-
ganese. M. Caron con^idei's that if this amount could be in"
creased to 10 per cent, the oommercial value of the pig iron wonld
bo increased."

The vast stiporiority of steel, as a material for resisting extrenM
strains, leads us to expect that it will eTeiitn<tlIy occupy
c>nstruotive arts the position which wrought iron now occnpiea
•■ contrasted with the past use of cast iron. Steel produced by
r process seems to be of excellent quality, and of
~" )nly problem remaining to be solved
(j,of this Btee\ in \b.t^ i^>io,\is;v\.\a6 a^ &

^fet

EXTENDED USE OF STEEL IIT COBSTRCCTIOy. JIB

When such is done, we shall find that it will be bi tlio
intereEt of eugineera, in eveiy sense of the wonl. to ulopi socb •
safu anil mnst tniatworthy materitiL We may then expect to f««
ateel cyliuiler^ steel boilers, ateel ahijis, and armour plates, ami
ill shiirt, everything at present of iron will be maile of steel H
Jiiiif the expenditure of roaterial, and with incrt«sed durability.
lli^l'ore thi^ however, cun be dune, and in addition to the prO'
'liiution of such quantities of steel at h che«p rate eiigincvn
nill require to be provide<i with data indicating the beliafioor
it( steel under diilereiit circum stamps, as in ehips, boilers, and
utber atructuree. Until such are supplied, engineers will be slow
iiiid cautiuoa in their adoption of steel in many instances whvie it
might yield good resalts. We would ttierefure suggeiit to tbuw
interested in the general introduction of steel as a substitnte for
wiijught iron, that tliey should comluct such experiments as wonI>]
enable them at once to supply the necessary data to engineero,
and thus bring forcibly before their attention the demonstrated
mlvantage to be derived by the adoption of such a material

III all the TBried appUcations of llie three conibinatious gf
iron with carbon, considerable difference of ojiinion exists as to
how far we should trust such materials under str.iin or load. Of
coulee, tliis materially depends on the quality of the sani|>le in
u^^e. The breaking load of ^ny iron can be ascertained by the
simple experiment of testing a bar one inch square till it breaks.
This lias been done with almitst every quality of iron, ond will
lie found recorded in almost every engineers Pocket Book; it
is, however, usual in casting large work, to cast at the same
" pouring,'* a test bar, so as to ascertain the exact breaking weight
the particular iron or mixture will resist. Once this is known
the question presents itself, What is the Factor nf gafeiy at which
it Would be prnileut to load such a casting 1 '111 is is the questiiin
to which scarcely two engineers will be found to give the same
Professor jRiinkine, in hia " Civil Engineering,'' gives

fa £jllowii]g as examples of actual practice ; —

ENaiNEEHmO FACTS.

Ult. Stmngth
Proof Strength.

Ult. SCrangth
Workiog Loud.

Proof StrengUi
Workip"^ Load.

UrdinuxSW^ ">* Wrooght
Iron, StBaaj loftd

„ „ Mo-mgload
Wrought Iron riveted atiac

CsBl Iron Steadj Innd
„ ,. Moringl™!

1-5

2-<\
■2-0

3'0
2to3
30

3
4(ofi

6toS

1-6

2-0
about 1-3
2 to 3 68

The abuve three columns repreBsnt the ratio in which the
tUtimalB Inail should exceed the proof load, the tdtimate load
the working load, and the pronf load the worMng load. It is an.
established maxim to err on the safe side, but it is unquestion-
ably erring at best wben material is needlessly employed, to ae-
oure an over safety in any Btructnre ; it is, therefore, important
that Bueh a aabject as this should be set at rest. For its further
illustration we quote the following ex-celleiit paper on tile
Itelations iKtwcen the Safe Load and tlie StreDgth of IruHi
by Zerah Colburn, Esq., C.E., read befure the Society of
Engineers:—

" A great number of experiments have been made ty many
experimenters, to ascertain the ultimate resistance of iron to
tension and cnmpresaion, and its strength has thus been deter-
mined with perhaps as much precision as is possible in the onse
nf a material presenting almost constant variatiims of quality.
Every engineer is now aware that, as an average result, the ten-
sile strength of cost iron may be taken as about 8 tou^ per square
inch, anil its crualiiiig strength at 48 tons. Wrought iron of fair
quality will bear from 26 tons per square inch in tension, while
its crushing strength is variously stated at from 12 or 15 tons
per square inch up to 28^ tons, the last named being given by
Mr. Mallet as the result of experiments upon large hammered
bars, which bore but from 23 tons to 24 tons in tension,

" When, however, we come to the question of safe-working
strength, much difference of opinion exists among engineers, the
permanent supporting powpi- of iron being variously estimated ftl
i-IOths down to 1-lOtli of its breaking strength. Thus when,
meMteea years ago, a BAja.VGumuuKibuitxBaS.ta vtv^xinSsAftr

STRESOTU OK IRON STltUCTCRES.

GlympP|
.uW never 1
The L>1« I
a ratio of '

applicnticm of iron to railway etruetures, the Ute Mr. GlynS^
his evidence, recommended that a caat-iroa bridge slioulil d
be loaded bejond one-tenth of its nlthuate strength. ~"
~" '. Stephenaor, with several other engineer, thought a ratio of
sixth sufGcient, wliile the late Mr. Brunei vaa satislied wiUi
^ ratio of from two-fii'ths to one-third; or, in other words, if a
rder would just bear 100 tons of distributed load, he vouM
int from 33 tons to 40 tnna upon it, where Mr. Stephenwin
would allow not more than 1 7 tons, and Mr. Gljnn only 1 tons.
" Were we now to have another commiiision intrusted with th«
tame inquiry, it is not nnlikely that as great a difference of
a would be found still esieting. For there is no acknow-
idged natural principle upon which the safe load of iron has yet
a determined, and in the absence or oversight of such a prin-
tple each engineer must be governed by his own judgment of
wtiat is safe and pmdent. It is true that the authority of the
Board of Trade has been so iar exercised in this matter as to
have limited engineers, in the design of wrought iron railway
""iridgea, to maximum tensile strains of 5 tons per squure inch ;
md. although it is commonly believed that with wrought iron a
SompresBive strain of from 4 tons to 4 j tons corresponds to a
le strain of 5 tons, the Board of Trade impose the same limit
t strain for both the top and bottom chords of a wrought iron
ptder. The limit of 5 tons per square inch, it is hardly necen-
_ /to say, is an entirely arbitrary one, nor is it modified accorl-
ing to the quality of the iron and workmanship in a structure.
Thus, in girder bridges, plate iron is used, of which the breaking
strength is occasionally not more than 18 tons per square inch.
In punching the rivet holes, however, and irrespective of the loss
of the metal actually punched out, the solid iron remaining botweau
the holes is injured, so much so that. In a series of esperimenta
mode many years ^o by Mr. Fairbairn, the mean tensile strength of
1 specimens was rediiced from 53,486 lb. per square inch
e punching to 41,590 lb. per, square inch of solid iron left
een the holes after punching — more thiiii 20 per cent of the
angth of the iron being destroyed by punching, a loss distinct
a that of the metal actually punched out. Drilled rivet holes,
a satisfactory to know, are now being adopted in the bevt
»o(bivige work) but in bndgea olteaili erected and contoiit-

F

ENGINEERING FACTS. [Dit. VH.

ing plates occasionally no stronger than 18 tons per square inch
before imnchinj;, the loss of strength ascertained by Mr. Faiti-
bairn would diminish this to ahout 14^ tons for the net section
of metal betvi-een tiie rivet holes. Ou the other hand, the best
■nspenaion-briiige links have a strength of from 26 tons to SS
tons per square inch of section, and yet the Board of Trade in-
specting officers wonld not probnbly depart from the arbitraij
limit of a nuucimum strain of 5 t<jn3 in either cnse. As far,
therefore, as is necessary to meet the requirements of the auUio-
ritiea, good iron and sound workmanship go for little or nothing:
uid not iinty does this remaik apply to the inference of the
&)ard of Trade, hut in the cose of Chelsea suspension-bridge, the
chains of which are believed to have a teuaile strength of up-
wards of 25 tons per square inch, two of the leading members of
our profession have declared that structure to be unsafe until it
shail have been so strengthened that the greatest load which the
heaviest traffic is likely to bring upon it shall not exceed 5 Uma
per square inch of the sectional area of the chains. The hig
authorities, we are juatilied in siippoBin^, would, at the b
time, be satislieil with the same taasimum strain in the chords
of a pkte girder bridge, oven if the actual breaking strength of
tlie solid iron between the rivet boles did not, as we have reason
to beheve it often does not, ezceed 15 tons, or three-fifLfaa that
of the links of Chelsea Bridge.

" While some of the conditions of elastic action are now onder
consideration, it appears desirable to define, as neatly as may be,
what elasticity really is. We are all familiar enough with its
manifestations, as in a watch spring,, an air cushion, or a, bit of
india-rubber, but we seldom inquire to what condition of matter
these manifestations are to be attributed. When, however we
regard matter of any kind as a collection of distinct molecules or
atoms, between which the force of attraction is always predon
nant in solids, and the force of repulsion in gases, we have no
difiicuUy in pereeiving that any alteration in the amount of either
of these forees, acting within a body, must produce a correspond-
ing change in the dUtaiice between its atoms, and in this vei;
change of distance we have the whole phenomenon of elasticity.
Elasticity is nut a force, but the result of the antagonism of two
opposite forces r an antngoiuam la. ■wiwAx. evCaai ^\sa ums.'

k_ ^

F

^Tfe act t

EIJSTiaTY OF IKOy.

I act through a certain range or (iislance — a range dilTieriiig
greatly in different matwialB— before being completely oTercome
by the opposite force. Under the influence only of attraction
tiie particles of all mutter would cohere, and without repiilsion
tliere coulil be only solid bodies in nature, for the existence of
liquids and gases would then b« impossible. The repulsive force
appears to be tlie force of heat^ to which physical tepnlsiou may
!« generally traced. Under the influence of heat alone, and
without attraction, there could be neither cohesion nor liquidity,
and all substances could exist only in the gaseous state. We
ehall soon be able to trace the hearing which these distinction*
have npon the elasticity of iron. At present we have only to
bear in mind that there is reasonable physical evidence to show
that the atoms of matter, so far as we can comprehend their ex-
istence, are never in actual contact with each other, even in solid
bodies. Iron, as we know, is a comparatiToly porous material,
since air and water may be readily forced through it under mo-
derate pressures. MeiTinry, it is well known, will rapidly insinu-
ate itself between the pores of an apparently eulid body, for gold
immersed in mercury will acquire the condition of an amalgam",
and will crumble to powder. We know, furthermore, that the
particles of most, if not all, solid bodies may be so far separated
by beat as to convert them into liquids, and it is quite reason-
able to suppose that, with an additional degree of heat, or repul-
sive force, all these liquified solids might, like mercury, and even
melted gold, he converted into vapours. Now, any force applied
after the manner of tension in a bar of iron, thus tending to
separate the particles, in opposition to their cohesion or force of
litual attraction, may be considered to act in the same manner

l^the repulsive force of heat. The point at which rnpture will
e place will evidently be where the particles are so far sepa-
i that the cohesive force is less than the tensile strain, hot
a good ground for supposing that, even after rupture, the
ms of the iron would again cohere could they be again brought
t within their original distance from each other. This, of

l»Drse, would be impossible if we attempted merely to place the
two friictured surfaces in eontaet. In the case, however, of two

clean surfaces of load, we may readily bring them so chisBly to-
g^titar aa to restore cohesion, and, in Ute same way iron journals

EHQINEERINO FACTS. [Dir

I'

^B-«uijning in steel beai'inga occasionally becorae welded to tliom
^Kwlien the pressure ia tuo great for ordinary work. In. tliiu
^■bringing two bodies within the range of cohesive force, we Dinst
^Pnmember that it is the ultimate atoms which cohere, and that
tlie finest perceptible particle of matter may really consist of
myriads of almost iitfiiiitelj smaller atoms. In all welding we
first employ a di^gree of beat siifticient to overcome so much of
~ e cohesive force between the atoma of the iron as to allow ol
L sufficient motion among themselves to bring all, or moat of the
I mtoras forming one surface, within cohesive range of those forro-
r ing tlie opposite surface. Two cast-iron surfaces are readily
welded together by running melted iron betweeo them. With-
out heat the two Burfaoes, however well-finished, would touch
only at a great number of separate points, although there would
be considerable cohesion even then, as every one knows who has

J.lrought two carefully soiaped surfaces of iron, or two sheets of
flate-glaaa together; and although a part of the apparent COh»-
rion is due to the pressure of the atmosphere, there would ivolly
be some cohesion in a vacuum. It is only from the fact that
the atoms of matter will always cohere when once brouglit si
ciently near together, that we are enabled to make bricka and
all articles of earthenware. Soluble bodies, tike clay or sal^ oo-
e after solution and evaporation, simply because their atom^
laving been lirst separated hy the liquid solveiit, are again left
ohesive range on the evaporation of that solvent. Brick%
Kit for the waste of fuel in burning them, might he made &uni
Kithe most dilute solution of clay, and the final baking is only
B'aieces.'jary in order to so completely expel the moisture as to
'iring the clay atoms witliin the range of cohesion, but their own
character is in no respect altered. Iron, were it possible to di*-.
ivithout combining it with nitrogen, oxygen, sulphur, or
iither matters, would again return to its ordinary granidar
•»nd would recover its cohesion, on the evaporation of the sol-
vent. Great pressure, too, will effuct oohes'
Bobstances naturally having none at all Thu^ in experimeols
made with the ballistic pendulum to ascertain the velocity of
Lnon shot, the sand packing against which the shot is fired is
n converted into anntlstone of consideriihle atreJigtlt
I "From the illustrations given, IW c'Vb^^.ua'^.^ erf anliila " pp g^a

ELASTICITY OF IKON. SIB

loro tiian Lhe rauge or play of the attractive and n;-
hilsive forces of matter, aa variably eKert«l, bnt williin t)io
mils of rupture or cnjshing. Tims elasticity is the same in
" bnd whether the repulsive or Bcparating force be extvriiaity ap-
pli«I, or whether it be that of beat acting between the inoteiiiilea
of tliB body. If a bar of good wrought iron be stretched to the
1-lOOOth part uf its length, corresponding, say, to a strain of 10
ti)U9 per square inch, its elnaticity will be fully excited or nearly
so, and it wil! not support a much greal«r strain without taking
a permanent set. It is true that, if the same bar of iron, when
nut under strain, be heated to from 160 to 200 deg. above its
normal temperature, it will also elongate by 1 1000th part of its
length, and that without injury. But if this elongation takes
place under a compressive strain, or, if the iron, hi^t raised in
temi>erature by 200 deg. and thereby elongated, be attached to
two fixed points, and thus, while cooling, be made to contract
under HtraJn, it will be found that an elongation of not far from
1-lOOOth of the orii^inal length of the bar is the most that can
be borne without injnry, even when that elongation ia due to
lieat alnne. But if the iron be first heated sufficiently to soften
it, as railway tyres and gun hoops am heated, the particles will
be re-arranged, and, within certain limits, without injury; but
after the metal lias once cooled below the temperature at which
the particles have the mobility necessary fur this rearrangement,
any further contraction arumid an unyielding objtct wiU be at-
ided with permanent, and, there is reason to heUeve, injurious
Even in setting railway tyrea, it is believed to be best to
t them on cold, and under graduated pressure; and in tiie
B of gnn hoops. Captain Blakely and Mr, Mallet, who appear
I'bo entitled to the credit of the modem system of the ringed
iBtruction of artiUery, have always insisted upon the import-
e of a definite degree of shrinkage of each ring, so that the
consequent strain shall not exceed the elastic limit of the material.
Sir William Armstrong has stated that he does not consider any
pspecial accuracy essential in the distribution of the strains im-
Darted by shrinking his gun hoops upon each other; but it may
~e questioned bow far the failures of so many of the Armstrong

s have been due to neglect in this respect.
V'lt would he interesting to know the pi'ecise manner in which

EHGINEKRING FACTS. piv, TO,

suparatin^ strain acta upon the molecules of iron, ot r^tliut U
mow tlie succeKiive positions of the atoms during the apptita-
in of the strain. We are, however, without any posi^Te
lowlodrra of the positions which the atoms assume in sulidifl-
tiun and urnler Puhaeqnent forging; but the nmltifariousforai
which all atoms visibly crystallize serve to show us that th:^
,nnot all he at equal dialances from each other tliroughout tha
'hole body. If they were, the arrangement would be that e!
Litnon halls in a triangulrir pyramidal pile. Could v
<|ii«sent the atoms as occupying the angles of an infinite nambw
if tiquilaterfLl triangles, we should understand that a. linear st
sting to separate any two of the atoms would, at the same tim^
raw a third atom, if not a. number of atoms partly between them,
.nd when, from this intrusion, the repulsive force, or hen^ sl-
ays enveloping the intruding atom, had onoe overpowered the
;tractive or cohesive force existing between the two atoms thni
ITained apart, these would, in turn, cohere anew to the atom
'hich had been drawn in between them, and thus we should have
permanent rearrangement of the atoms, or, iu other word^ a
srmaneut set, with permanent elongiition in one direction, and
jrmanent contraction iu a plane at right angles thereto. That
te atoms are thus drawu into parallel rows of straight lines, ii
any kinds of iron at least, seems evident from the appeafanoa
', fracture, which presents stringy collections of particles forming
hat is commonly called fibi'B, although there is great r
mbting that anything like tibre existed in the iron befin^ h
as broken. Mr. Kirkaldy's recent extensive experiments appear
show, as many others have shown, that iron may he made to
short or to break with an ajipearanue of libra, just accord-
it is broken with a sudden blow or a gradual pull SomS'
hing like fibre may be imjiarted, on a viiarss scale, by repeated
oiling or in wire-drawing; but it is more probable that a
t atoms are thus drawn into strings than thut any fibre is really
mparted to the atomic arrangement itself.

' It is commonly held that, within certain limits of strain, iron is
erfectly elastic. No nutter how ijften it ntay be streteiied o
scted, up to aoertniu point the general beliiif it
k to its original form every time the load is taken o
Jl^h authorities, however, whu Toaiatiuin tbai ii

ae streteiied or de-

s that it will come 1

taken ofC Tiiera I

ct iion. takes a pet- I

SET OF CASTING UNDEK PUESSURE. 8S1

lent set andFr even veij moderate slraiiis. If we are to uiidet-
lad that thesetisesce«dingly email, this may be tnip. Hie late
pfr. fiodgkinsnn, for example, remarked, on th« 36 Ut p-ig« of
Ilia 'Experimental Besearcbos,' that two cast iron beams took eacli
a permanent aet with weights respectively equal to l-£7tli and
1 -80th of the breaking weight. In a discussion at the Iiistilutii >n
of Civil Engineers, a. Mr. Dines mentioned that he had tested
apwards of 8,000 cost iron girders fur the late Thomas Ciibitt, and
that he found it hardly possible to apjily a we^ht so small as not
to produce eimie permanent set, I -20th of the breaking weight
producing a perceptible set. In the experiments of the Iron
Commission at Portsmouth a bar of annealed wrought iron 60
ft, long was said to have taken a perceptible set with a weight of
less than 1^ ton per square inch. After this weight had been
doubled, however, the set was still only perceptible; and not-
withstanding that the elasticity of annealed iron is known to be
inferior to that of unannealed bars, the whole set of the GO ft bar
was hut the 1-S50th port of one inch, after a strain of 8^ tons per
square inch had been borne; and the set was but the l-20th of
an inch in 50 ft at^r a strain of 11 '9 tons per square inch.
Mr. Edwin Clark has experimented on a wrought iron bar 10 ft.
long and 1 in. square. Under a strjjii of 3 tons per square inch
he gives a permanent set of nearly the l-4000th part of an inch
in 10 ft. With 8 tons the permanent set is given as about the
l-1280th of an inch in 10 ft., and it was not until a strain of
13 tons per square inch had been applied that a set of l-33d
of an inch in 10 ft became apparent. With such exceedingly
niinnte measurements, we mtiy, perhaps, doubt if there was really
any permanent set at all, with strains under 9 or 10 tons per
square inch. An increase of temperature in the bar of perhaps a
single degree, while the measurements were being made, would
more than account for some of the reported sets, even under con-
siderable strains. Thus Mr. Eilwin Clark gives the permanent
set of his bar, after a strain of 8 tons per square inch, as the
1-153, 846th part of its length, and this ia almost exactly what
the extension of the bar would have heen hod its temperature
been raised but a single degree between the observations. Iron
is heated in the very act of straining it, and a suddtn breaking
strain will generally leave the broken ends too hot to he handle"!.

EMGINEEEISO FACTS. [Ttw.

B 322

^K Siicli ft sliglit apparent extension miglit aho have occariixl wUle

^B the shackles by which the bar was strained were coming to tiiot

^H bejiriiigi £ut even if such a microecopic permanent set mlLj

^H existed, it is one of which no engineer would take the slightest

^H Berious notice as afTecting the strength of the bar in which it vu

^1 uliBurveil. "With the means of meosui^ment commonly employed

^V by engineers ordinary wrought iron is seldom permanently

^H stretched until after it has borue strains of upwards of S tons

^H per square inch. In seven esperimeuta by Professor Barkn?,

^M on wronght iron bars 10 ft long two of them retained their MX

^F elodtieity under a strain of 11 toDS per aquare inch, three b

bore 10 tons wiibout injury, while one bore 9^ tons, and anotiien

miide from old furnace bats, did not rettun its elasticity beyond

a strain of 8^ tons per eijuare inch. All the links for the PsBtll

» Suspension- bridge, upwards of 6,000 iu number, and 12 ft. long
frijm centre to centre, were tested without permanent set up to
& tons per square inch, and those of Chelsea Suspension-bruJgB
were tested without permanent elongation up to 13^ tons per
aquare inch. Mr. Edwin Clark, from the results of his experi-
ments, considers that the limit of elasticity of wrouyht i
tons per square inch, and this appears to have been adopted by
^^ him both for bars having a breaking weight of 24 tons and (or
^^L plates having a breaking weight of ^0 tons. Every chain cabls
^H purchased by the Admiralty is tested up to 11 '46 tons per square
^V inch of the metal in each side of the linlt, the standard test being
630 lb. for each circular ^ in. of the diameter of the ii
witich the cable is made, oue-half of this strain coming
each dide of the link. The iron of which the cables are nutda

»does not, as a rule, take any permanent set when strained to this
amount, or to say 11^ tons per square inch. Mr. Howard li
stated that the best iron begins to stretch permanently Dud
Bbout 10 tons per square inch in 10 ft. lengtlis, aUhough be
occasionally testa up to 16 tons or 16 tons per square inchj
' breaking weight being from 26 tons to 28 tons. Miv %bll«^
about four years agi), presenteii to the Institution of Civil En-
gineers the results of a valuable seiiea of experiments i
■wrought iron and puddled stool, from which it appeared that the
I elastic limit and the breaking strain under tension were, ii
use of certain samples, as foWo-^ ■,—

ft.7

BREAKINO STOAISS Of IRON.

^^Kiiammered sUb or bar, 12iii. bj lin.
^^H ilBinuiered bar
^^1 Rolleil slib or bur 12in. bj 4iD.
^■Boiled bar ....

^F Fajopted forged sUb, tR. Y.y 4ft. by
^r Onffaal fa^cot burs, Horsfall gun
I lAD^tudiiui] cut, forged musa

I CiTi'umferentviil ,,

Tmnsveiso ,, ,.

(L'hiti'coiil rolled bar Crom boring from tlie Hi
lull gun

" Sir Marc Isamliflrd Brunei matle a miniber of esperiments
un Yorkshire irOD, liammeivd to small dimensinns, or from | iti.
Uj ^ in. square. A very Ligh elastic limit was obtained, as

" Mean of ten bars began to etcetch with 22 '2 tons per equare

belt, tbe mean breaking weight being 30*4 tons per square incli.

pith ten other bars the mean strain at trliiuh tliey began to

retch was 24'4 tons, the breaking strength being 32"3 tons.

r square inch. It is to he burne in mind, however, that these

) reduced hy the hammer only at the centre of thei

ingth, and that, therefore, the stretching could be observed upon

lit a veij small part of their length. Mr. John A. Eoehling, the

igineer of the Niagara Suspension-bridge, has mode e.xperi-

mta upon bars similarly drawn ilown to j in. square at the

'e breaking weight being 33 tons per square inch;

J bats bore a strain of 20^ tons per square inch without

sibly stretciiing, and when no jar was given to the bars they

h)uld support this strain for a week. Upon any vibration, how-

fter, the bars immediately took a permanent set.

" Dnder strains, bowover, considerably within the elastic limit,

K gradual rearrangement of the particles of the iron c

"and if the strain be contiimed suiSciently long, permanent set

will after a while take place. Tlie late Monsieur Vicat, whose

work on limes and mortar is so well known, began as early a

^^830 to investigate the effect of continued strains on nnanneided

^bran wiio. Ha applied various strains to similar wires of a known

^Hpreahin^ Bb^ngth, and continued these strains from July, 1830,

821 ENGINEERING FACTS. (Div, 711,

) dctober, 1833. Ocie wire was strtiiuBil to one-fourth ik
breaking weight, but beyond the elongation which at ODce twli
[ilace no additional stretchiug oecurred in thirtj-three months,
A second wire was etrained to onB-tbird of its breaking weiglit,
nd in thirty-three months it stretched at the rato of 2f putt
u every 1,000 parts of its length, this stretching being adiiitiona!
that which took place as soon aa the weight was applied, \iat
rh'ich, of itself, was not suffitiont to immeiiiately prodoce bjij
jHTiuaneut act. Under a strain of one-lmlf the breaking ireight
another wire stretched rather more than 4 parts in erery 1,000
parts of its length. Under a atmin of three-fourths of the break-
ing weight, a fourth wire stretched, in thirty-three months^ 6^
paits in every 1,000 parts of its length, and then broke, whicU
I circumstance terminated the experiments: Monsieur Vicat's
' account of them appeared in the fifth volume of the second series
; of the ' Annales de Cbiraie et Physique.' It is to be regretted
that, in place of the constantly recurring experiments upon the
breaking strength of iron, and which, as is already beginning to
be understood, give us hut a very partial knowledge of its avail-
able working properties, we have nut a lai^er experimental ac-
quaintance with the continued supporting power of iron,
afforded by experiments similar to M. Vicat's. Mr. Fairbairn,
it is true, m.ado an extensive series of experiments between tha
years 1637 and 1842, to ascertain how long bars of cast iron
would support weights equal to about 1 9-20th8 of their breaking
weight, fiy taking care to prevent any vibration in or about
the hiLra, several of them continued, for five years and upward^
to support nearly their full breaking weight. Their deflection
steadily increased, however, during the whole time, and Mr, Fair-
bairn has stated that some of these bars afterwards broke with
but l-20th of their original breaking weight. As bearing upon
I last-mentioned circumstance, it may be remarked that M,
' Vicat, writing in 1833, observed that Monsieur Henri, on en.
^ ginecr serving in Russia, had already shown that iron which had
once withstood a great proof strain often broke sometime
wards under a much less strain. This fact must indeed hava
been known to practical men even earlier than in 1830,

" Now, in employing iron in any structure where it is sub-
J fcoteJ fo strain, we seek to kee^ viitlun its luiiit of elaa^cL

STRENGTH OK IRON USDEB STRAIN. MS

■ Vet nut uiily have we but a compantively small number <>r ru-

■ curdeil experimeuts to show us what thia limit is, even under a
1 "^iiigls and temporaiy strain, but wb have, at least, the result of
J SL Vicat's exjieriments to show us that we cannot depend upon
I unything like this limit uniler a Ion g-onu tinned stniin. What

experimental knowledge we hare goe« to show thst the origiiiat
(-'Imtic limit of iron is greater wlien hammered than when rolled,
but we are unable to count with any degree of certainty upiiii
the ultimate superiority of hammered iron, in this respect, after
l>>ug-continued strain. Aa a rule, also, — the abundant evidence
of which it ia not, perhaps, necessary to introduce into thu
present paper-— all harsh, hard, crystalline irons have a higher
•elastic limit, in proportion to their breaking strength, tliiiii
soft, ductile, highly fibrous irons — like Swedish bar, for ex-
ample ; — that is to say, the harder irons will bear a greater
striiiu before taking a permanent set, although, aa we shall
presently have ocuasion to inquire, it may not follow that they
are really superior to other irons which are more readily
stretched, and which, indeed, may have an even less breaking;
weight. What information we have goes to show that there is
no settled relation between the elastic limit and the breaking
weight of iron ; the former is much more variable than the latter,
and can hardly be expressed at all as an average result, ranging,
OS it does, from less than onefoui-th to more than two-thinls of
the breaking weight ; or if the elastic limit be taken irrespective
of the breaking weight, the instances already cited show that the
former vories from SJ tons up to 24^ tons per square inch in
different qnaUties of iron, although the range in ordinary bur
iron and plate iron is not nearly as great Now, no engineer, iu
appoitioning the strains in a structure, wonld think of working
up to, or near to, the breaking strength of iron. His object is
to keep within the elastic power of the material, not merely a
ftsoertoiued by a single strain of a few minutes' duration, but tlie I
continued elastic power of the iron as exerted through a very I
long series of years. We ought by this time to have hundi'ei.ls I
of trustworthy exppriments upon this point where there is i
one. If the safe working strength of a rautal is limited, a
1' "Would appear to be, by its measiire of permanent perfect elasticity J
M-iK may aay that we hardly know, evefl yet, wb^j^^^treugtl^

I
I

32« EKGJNEERING FACTS. [Div. VIL

of the materiiila we are conetantly dealing witli, uotwitlistuudiiig
tbat not a jrear passes without some udditiun to our stock ( ~
knowledge of breaking weights.

"Willie we ate about considering the permanent injury which.
iroa Buffers when strained beyond its elastic limit, it is to be u
deratood that iron may be strained for a short time almost up to
the breaking point without in the least diminishing its strength
under a breaking weight subsequently applied Indeed, in gradit-
ally applying the breaking strain to any sample of iron, it is
clear that it must have borne 10 tons before it is subjected to k
strain of 16 tons, aud that it mu^it have borne 15 tons before iG
is strained to 20 tons, and so on. Sot only is this the c
after a bar of iron has been actually broken under a tensUe strain,
the two broken portions of the bar will almost always require a
still higher stmin to break them. Ihe weakest spot in the bar
will fail first, and although the breaking strain will at the
time permanently stretch the bar throughout its whole lengtli,
the iron on each side of the frActure will still have its original
breaking strength. Professor Barlow's Treatise on the StrengtU
of Materials contains the results of several experiments made at
"Woolwick Dockyard, as follow ; —

"A bolt of Solly's patent iron was nicked at one place, and
then broken by a strain of 26'7 tons per square inch. One of
the pieces was then tried and broke at 29^ tons. In the next
experiment a bar of the same iron was first broken with 33^ tons
per square inch, then again with 26^ tons, a third time with 26{
tuns, and a fourth time with 25| tona,

" Mr. Thomas Lloyd, engineer to the Admiralty, made a like
series of experiments a few years ago, on ten bars of SC crown
iron, 1 1 in. in diameter, and 4^ ft. long. The mean breaking
weight at the first breakage was 23'94 tons per square inch,
the second breakage, with pieces 3 fl. long, the mean strength
was 25 86 tons per square inch. At the third breakage, with
pieces 2 feet long, 27 06 tons per square inch ; and at the fourth
breakage with 15 inch lengths, 29'3 tons per square inch. Mr.
Lloyd's experiments have been held to show that iron was ac-
tually strengthened by stretching it, or, in other words, that by
ilestroying the cohesion, at o\ie ^oint, the cohesion was every-
wiere else increased. A.moi6obN\o\is. «s.-^iaM.'C\KiG.Ss^'iiai,.y

w

N.] STRENGTH Or IBON 33;

first bioko at tlie witalccst port, then ^aiu at the nexi n-oak-
part,ftiidso oil AvaristioD of from 2394 ton^ to 39 '3 tons
the stretigtii of the Game bur ia undonbtedl; lac;ge, the greater
igth being 22 pec cent, more than the leaser, a (lifTerence
vhich appeared to exiat in each of the ten ban triisL It ia well
known, however, that liardly any two bare of iron hare exactly
the same strength, and Mr. William Boberts, manager of Me^rs.
iwn, Lenox, and Co. 'a extensive chain cable works at Miliwall,
cut a 12 ft bar of iron into 2 ft. lengths, and found, nn
that there was a difference of strength of 20 per cent,
'een the strongest and the weakest of these pieces. In the
experiments of the lioilway Iron Comnuasion ujKtn the exten-
sion of cast iron, the strength of Lowmoor cast bars was 7'32S
tons per square inch at the first, and 8'153 tons at the second
'eaking. Blaenavon iron broke with 6'S51 tuna per square
at the first, and G'738 tons at the second breakage. Gart-
. broke with 7'5C7 tons per square inch at the firGt,
8'475 tons at the second breakage. Otlicr cast irua bars
a certain mixture broke with 6'6I25 tons per t«quare incli
at the first, and 6'777 tons at the second breakage, the latter
being at an unsound place. Upon these results the commission-
^ remarked that 'it would appear that iron, repeatedly broken,
iomee more tenacious than it was originally. This erroneous
iclusion may be obviated by considering that it would be very
dt, if not impracticable, to obtain cast-iron bars perfectly
Bound and 50 ft. long. Fracture may be supposed to take place
the first time at the largest defect, and subsequently at those
smaller, until, finally, none remain.' It is not intended, how-
ever, in the present paper, to entirely deny that the breaking
strength of iron may be actually increased by being stretched
when cold ; and this point may be left as an open question.
That iron is so strengthened derives some probability from the ,
*;iiowu lad that its strength is greatly increased by being drawn 1
lid into wire, and also by cold rolling. When heated moder-
ly, or to less than a dull red, and then stretohud, iron is
igthened throughout This treatment ia known as thermo-
and in an extensive course of experiments made about
iwenty years ago by Prefes-ior Walter K. Johnson, for the United
Government a total gain of nearly 30 per cent, in sticugth

K«etti

nS8 ESnlN'EERlNG FACTS. [Rrv. VM.

' aiid length, taken together, was estimated to have been oLtaiiii^il
with a vuri«ty of irons. A bar of irou, having a strength of 6'
tone, WP18 heated to opwarda of 500 deg., and tljen stretched bj
6^ per cent of its length, when it ftGqiiiteii a strength of 72 tolia.
Cftptain Blakely has liilely proposed the same treatment of iron,
and his experiinonts, it ii underatood, corroborate those of Pb>-
feS3or Johnson. All the links made for the four great pitch

_ chains employed, with the steamship Great Britain's engines, for
jetting up the speed of the screw, were stretched ^ in. while at
k dnll red heat

"But from what has heen said, it is not to be supposed that
a ia not injured by excessive strains, notwithstanding that tin
metal strained may, when tried immediately afterwarda, still re-
tain its full breaking strength. The injary will appear whsn B
subsequent working strain ia long continued; and even without

Ivaiting for this, it will be found that the strained iron has been
deprived of a large part, if not the whole, of its natural elasticity.
In B paper of great value, raad nearly seven years ago before tbd
£oyal Irish Academy, and afterwards published in a quarto
volume, entitled, 'On the Physical Conditions involved in tha
Construction of Artillery," Mr. Robert Mallet has laid down B
uceful mea-sure of the working and ultimate strength of iron.
Poncelet had already employed coefhcient^ which indirectly ex-
pressed, not merely the elastic limit and breaking strength of
iron, but the range also through which the force acted in each
ease in reaching these limits. Mr. Mallet has adapted these co-
efficients to the English standard of mechanical woric, to wit;
' foot-ponnda ; ' and he represents the structural value of diffBrent
materials, or of various qualities of the same material — in
ca^e by the pi'oduct of the elastic load in pounds into half Uie
range, in feet or parts of a foot, through which it acta ; and in
the other case by the breaking weight in pounds multiplied also
1, by half tlie range, in feet or parts of a foot, through which it
||-Hte. Mr. Mallet employs Poncelet's coefficients, as follows; —

= foot-pauidH in reocliEug aluBtio limit of tensioii.
= li •! to produiM) rupture Ity tonsion.
= „ „ in reatliing elastic limit in cotiipressioii.
2V = „ 1, to proiiuce crnahiug.

light into l\ua 'fl\uAfi. ftS,\«Ma\!«i, ot, -w^iat. ia

t*Aftt»fcji«fW«**ri«rifS rw iron.

B thing, the whole ireiglit uito half Iha ext^nBion, i« silopUt]
" E force grailaally applied to brenk a bar must tncRiiM>
■ fTom nothing to the breaking weight. Upon Dr. Honke's law,
I lit tennio ma vtt, the weight of a grain will in some minate ilc<
I gree deflect or etiteud the heaviest bar of iron, and the deflection
iiT extension will iiiurease progreasivBly with the weight applied,
up to rupture. Therefore, if a. bar be stretched 1 ft, and then
broken with a weight of 33.000 lb., the work done will be the
mean of zero, and 33,000 lb. into 1 ft., or 16,500 footpounds.
This, as has been said, is the work done in the case of a grudu-
iiliy applied strain. IX however, the weight he applied without
impact, hut at the eunie time instautaneously, upon the bar, it
will, ao long as the limit of elasticity is not e^iceeded, and sup-
posing the bar to have no inertia, produced twice its former de-
llection, and, therefore, twice the ultimate strain. For the
weiglit, in failing through the distance of the deflection due to
Liie load at rest, will acquire momentum sufficient to carry it
<:hrough an additional distance equal to that of the static deflec-
tion. This may be best demonstrated experimentally with tlie
aid of a spring balance. If uptm th« plan of a balance suffi-
ciently strong to weigh up to 40 11.., a weight of 15 !h. be
placed, and this be then lifted to zero on the scale and there
released, it will descend, momentarily, to nearly 30 lb. o
scale, and if there were no opposing resistances and the spring
had no inertia, it would descend to exactly 30 lb. In the actual
application of strains in practice a weiglit is never thus appUed,
but a consideration of what would occur under such circumstan-
ces is sufficient to show how important it is that Tibratory action
be not overlooked in considering the strains on bridges,
to be remembered that this action of suddenly applied loads i
only manifested in the ease of the application of weights; for if j
the strain he produced by the sudden admission of steam or any /
other practically imponderable body, no additional deflection will J
lake place beyond that due to the pressure acting statically,
vteam pressure acted in the same manner in this respect a
weight, the steam indicator would show nearly or quite doubleB
the pressure acting effectively within the cylinder of the engineM
" It will not be attempted in the present paper to enter full J
into tiie application of the coellicientB adopted by Mr. Midlell

r

830 ENfJlSEEltlSU FALTSl [Dit. TO,

for there are objections against, as well as reasons in favour ii(,
their application. It is evident that T r may be the same in
two cases — in one of which a liigh breaking weight is exerted
through a very short distance, and in the other of which a luw
breaking weight produces stretching through a correspondingly
greater distance. But this coefficient does possess a value b
taking account of the combined cohesive force and extensibility
of iron, instead of the breaking strength alone. As Mr. Mall^
justly observes, glass has a high cohesive force, and ia, nev^thft-
less, nseless under strain, owing to its brittleness, while caout-
chouc has great extensibility or toughness with but slight cohenon.
The products, therefore, expressed by the coefGcieats in queedoo
do not afford a complete notion of the practical value of a gireo
material unless the factors whereby these products are obtained
are also given. The elastic limit of iron, however low, is not to
be exceeded in practical use, whatever its range of elasticity may
be; nor iloes it appear prudent to work iuto the neighbourhood
of a high elastic limit when the elastic range is known to bs
small It ia unt to be underetood that the cmftiGieiits in qm
tion are intended to apply otherwise than in comparison of ban
of equal length, else it would result that the measure of 7*' ia «
bar fiO ft. long, was one hundred times greater than that of a
bolt 6 in. long, and of the same material and sectional ai
Tor the purposes of the engineer a long bolt is not only
stronger than a short one ; but, as it can he no stronger than its
weakest part, it wil! follow that the average strength of 1 00 bolt«
6 in. long, is likely to be greater than that of a single bolt of tba
same diameter and 50 ft. long. Every engineer must be awan
of the importance of toughness in combination with cobesiTft
strength in iron, hut we need much more extensive and accorata
information as to the former ; and a consideration of Mr,
Mallet's coefScients should lead to additional experiments being
undertaken. It is but right to mention here that, in 1848, M"f.
Homersham Cox contributed a paper to the Oioil Engineefi
and Architects' Journal, in wliich lie represented the mechanioat
work, in foot-pounds, expended in deflecting a girder, the worfc
being expressed by the product of half the weight into the range
of deflection, Mr. Kirkaldy, proceeding upon an independent
•■ourso of inquiry, hut with Uie

w

^^■r. Mallet, has lately pablislied the re«alta of « most imptirtuil

^Beriea of experiments, whicli are the first upon anything like •«

eitensive scale, to take into account the cunibined cofai«ive fuive

mil extensibility of iron and steel Mr. KirkalJy ejcperiment-'l

upoa many Lntidroda of specimens^ but he did not ascertain

their limit of elasticity. He has giren b»th the origitutl dimcri-

sions and cross sectioDAl ana, and the dimensions and atea after

I fioctnre ; and he has also given the amoant of plongation at fne-

I, although be did not ascertain the extension of the elastic

The reduction of diameter of a bar at tlie point of fno-

a serves to gire a practical man a good idea of tjie quality of

~ ut it does not admit of an expression of the mechauioal

t done in producing fracture, as does the combined breaking

ight and linear extension. In tearing a bar in two, also, wo

Ive to consider the permanent stretch communicated to all

a of the bar alike, and the additional stretch at and near the

point of fiacture. That part of the stretehing which extends

uniformly throughout the whole bar would, we may suppoae, bo

exactly proportioual to the length of the bar; while thst part "f

the stretch which takes place claae to the poiut of frncture

would, we may also suppose, be a fixed quantity, whatever

might be the length of the bar. Mr. Kirkaldy's specimens of

'ton and steel varied from 2'i in. to 8*2 in. only in length, aiut

bitii these the ultimate elongation at fracture varied from nearly

^hing to 27 per cent, of the original length, whereas longor

s would have shown a proportionally less elongation. Tliu

Inplee which batdly elongated at all were of puddled steel'ship

One sample, whioh bore 63,093 lb, per square inch of

e original area, stretehed before breaking but the l-20th part

Q inch in a length of 7-6 in., or leas tbau T-lOtha of 1 per

mt. of the length. Adopting Mr. Mullet's coefRciunt, the

ructural value of such a material would be almost nothing.

1 fact, Mr. Kirkoldy found the puddled steel plates, through-

ont, to have much less extensibility than cast-sli-el plates, while

the former, also, were of very irregular breaking strungth. TIiu

interest attached to the subject of puddled steel may possibly

serve as a justilicBtion for mentioning this fnut, although

^^Enreign to the object of the preaeut papier, which bos to dvul

H»itb iron.

ESaiNEEKlNG FACTS. [Div. Vli.

" We have, op to this point, considereil the elastic limit w
itaneiit supporting power of iron uuder a single applioatioa
if stmiii, exteading in some cases over a few minutea, and id
others over some montlis. We have very little experimental
knowteilge as to the extent to which we may approach the elastic
lirait under continued strains; but there is a probability that a
continuous strain much exceeding one half of the elastic tlniit
I would he attended with gradually progressive permanent set. At
e time, with good iron, poasesaing a fair amount of es-
■ tensibility, a single temporary strain, producing a slight or even
~ eonaiderabte permanent set, may not diminish raateriallj the
strength expressed by Mr. Mallet's coefficient T r, and the iron
may stilt hold up indefinitely with an ordinary load considerably
within the limit of elasticity. But, apart from the consideration
of the time through which a strain acts, we have also that of
the frequency with which the load is applied and removed.
Fitirbaim loaded cast-iron bars to upwards uf nine-tenths of their
breaking weight, and this load remained on from five to s>
years before the bars broke down; bit with a repeated applio*-
I tion and removal of load, the Iron Commission experiments
I showed that iron bars, when repeatedly deflected by impact
I Ihrimgh one half the distance due to their breaking wei^t,
r^uke down after from 130 to 4,000 applications of the strain.
KUr. Fairhairn communicated some of the results of an important
if experiments to the British Aaaociiitiott at the Manches-
ter meeting, 1861, from which it appeared that a large model of
a wrought-iron plate girder withstood, without injury, 1,000,000
appliLations of a load equal to one-fourth its breaking weigb^
and afterwards 5,1 TS applications of one-half its breaking weight,
when it broke down. The model was then repaired, and 25,900
applioations of two-fifths its breaking weight, and afterwards
nearly 3,000,000 applications of one-third its breaking weight,
were made, it was said, without injury, although neither the de-
flections nor the permanent set were given. We know that iron
altera its form, temporarily, during the application of very mo-
derate strains, the elasticity of good iron being generally observ-
^nQjle with strains of one ton per square inch. And we know
^Bbat its form is permanently changeil, both immediately on ex-
^Kbeding tha lirait cf elustidly, a.ii.4 ^laiwaW-j Mnici it.t:imia'«aMt\;iti

bi

IT'
ti
d
i\
»

^hoM.] STREKGTH OF (BOX UMDEB CONTIKl'ED STBiJX. 333

Hapftroacbing that limit. TlH'n.* clearly most be a Tcorningemeiit
Hiif iLe particles of iron always going on wliere the strain u great ;
Bund a.s we know tliat when even a more moderate strain is eased
I off the iron tends to resume ita original form, it appears iuuoti-
I testible that final Injury must reisult under what may appear mn-
I derate, although irregular loads — say one-tliird, or even ratluT
[ le^ of the breaking weight. Iron, it is still to be tenieiubGrrd,
has not been employed long enough for purposes of construction
to enable us to compare ita endurance witji masonry, of which
there are abundant examples still perfect after many hundred
years. At the same time, it must not be foi^otten, that, while
we can never know the absolnte strength of a bar of iron without
destroying it under strain, neither can we always infer its
strength from its deflection, or apparent range of elasticity; for
we are not yet secure ^ainxt flaws or those other faults of mole-
cular atmuture which Mr. Malliit so well describes as ' planes of
weakness.' A bar of iron may have a general atrejigth of 22
tans per square inch, except at a single point in its lengtii,
where, for an almost inappreciable linear distance, the strength
may not exceed 10 tons. K the bar he broken this fault wiil hn
detected, hut hnrdly, if at all, otherwise; for under a strain of
even 6 tons or 9 tons, the extension at the precise point of
weakness would he so slight as to be quite overlooked in a
observation of the total deflection or extension.

■' In this fact, which was mentioned thirty years ago by M.
Vicat, and in the known effects of suddenly applied strains,
vibration, impact, &c, we have abundant reason for extreme
caution in the use of iron for permanent stmcturea of any kind,
Tt can hardly be said that the Board of Trade limit of 5 tons,
srbitrary as it is, is too moderate, aithough there shoidd be si
account taken of the known quality of the iron to which this
strain is to be applied; and it may nut be necessary to adopt I
an unlikely load as that which is to produce the mo
strain of 5 tons. The recent discussion as tu the security o
Chelsea Bridge affords much suggestive material upon thea
points.

" The application of iron to bridges, especially to thoa
It large span, necessarily requires the moat careful consideration ij
L apportioning the strains, since every pound of metal not brougll

^B sa

ESGINEERING FACTS. [DtT. W.

into effective actiou, is so luucli dead waiglit or nselesu load —
being not only niisappUed of itself bat requiiing ailJition&l nut-
t*.ria! to support it In considering tlie etraina upon iron,
tlierefore, reference haa been more particularly made in the pre-

I sent paper to its employment in biidges; but in the case tt
"boilers, iron ships, cranes, ordnance, railway bara, warehooM
giitlera and columns, roofs, engine beams, and in many other
applications, the most careful distribution of material and adjust-
Dient of strains is of very great importance. Iron la, pe^pi^
'more severely strained in steam boilers than in other stractaiea.
In the case of locomotive engines, there is a dispositto
ploy still larger boilers and to carry still greater pressures.
With 60 in. boilera, formed of 7-16 in. plates, double riveted,
and carrying, as is now not usual, from 130 lb. to HO lb. prea-

Ieure, there is at the higher limit a circumferential strain of SJ
tons per square inch at the joints, and a longitudinal strain of
nearly two tons per square inch along the whole length o
toiler, the resulting strain at tiie joints being nearly six tons
^r square inuh. Tiiis strain is constantly maintained with
plates ran^Dg from 21 tons to 2i tons in strength, and under
*11 the contingencies of corrosion, incessant vibration, and occa-
tdonal sudden ejtaltations of pressure due to the iustantaneoua
production of steam upon overheated tubes or plates. In masy
eases we have 4 ft. hiiilera with | in. plBtw", single riveted, and
worked at 130 Ih., corresponding to a strain of at least 6| t
per square inch at the joints of the boiler when new, the circum-
ferential end longitudinal strains being both taken here into ac-
count. Pnt under this strain when new, many locomotive
boilers are worked in all from ten to twenty years, and often

I from three to seven years, without any internal examination of
the plates. Tt is nbt remarkable, therefore, that explosions are
becoming so frequent.
""We may regard with much hope the increasing use of steel
En large masses, as produced by Krupp and by Mr. Bessemer,
dnd others whose discoveries have already effected a great economy
tirate stMinUction of that materiaL Although a departure frfm
able with sff the present paper, it is interesting also to refer
that its form'*^" °^ phosphorised copper, as now produced by the
oeediug tbn U *'"i o^liGr copperaiBfi\iCT4. Vt ■^aa wiasiinceJ,^

K>B,1 SAFE LOAD OF lEON.

^^hree years ago, as a new discovery by Mt Abel, chemist to tiio
War Department, that the addition of from 2 to 4 per c«nt vt
phosphoms to copper greatly iuLTeaseil its density and strength.
There is no doubt of the large advantage of this uombtnation,
although it was discovered in tlie last century and made puhlicly
known sixty years ago, A French chemist, M. Sage, contributed
a paper upon this subject to the Journal de Phygique, anil which
B trunstated into the 20th volume of the Philmopldcal Mag'i-
i, for 1806, By combining the maximum quantity of phos-
B with copper, the ktter acquired the hardness, grain, aud
■ of steel ; and although M. Sage ha<i already kept tho
mpound for fifteen yt-ars, it had suffered no change from ex-
a to the air. It was easily turned and took a fine poiiah.
E may yet be found that copper thus treated is the best material
r many of the purposes of the mechanical engineer.
"In conclusion, it must be regretted, if not indeed, deploi-eil,
it oar exact knowledge of the permanent supporting power of
a is eo limited. The present paper, it ia feared, will hardly
nil£l its title, which may have led to the expectation that some
tlefinite relation would he assigned between the safe load and
the ultimate strength of iron. Even at the lisk, however, of
leaving the subject as the author found it, he indulges the Lope
t the eonaideratiuns which have been touched upon may in-
closet observation and inqiiii'y into the real working proper-
s distinguished from its ultimate strength, Tlie
ition involved in this subject does not appear to he one which
aita of solution by a reference to any known natural law, nor
18 it appear that it oan be disposed of by mathematical inves-
ttion, but our only safe conclusions must be derived from the
olta of protracted, varied, and repeated experiment. In the
I prudence requires that we ascertain, with as
h accuracy as possible, the elastic powers of every given kind
a proposed for permanent works, and that we then so pro-
n the parts that the working strain shall never much ex-
ane half the elastic limit — a ratio which will correspond,
mrding to the variable quality of iron, with a load of from
■8th to l-4th its breaking strength."

> In testing iron work on railway bridges no special regulations
'e laid down in this country, the general course pursued being

I

ENGISEERING FACTS. [Dlv. VD.

to i-over tlie briilgo from cud to cud with locomotive engine
lieavy working trim, and to gauge Hccurately tlie deBeetiuiL
In Prussia a questinn is raised relative to the dilTereat ivga-
iHtiuns I'or testing railway bridges; as to whether it is safe tu
Dssuine a maximum etrain of 10,000 lbs., or about 5 tons &ig-
Jish, aa in France only 8,200 lbs. are allowed. The asBainp-
.tiun is that it is perfectly so. From the experimeuta made
on the deAectioDS of different coiistructiuns of girders, it is found
that the same depends wholly on the proportions of each con-
struction. '■ Calliug the ceutral deflection/ the span I, modolaa
uf elasticity E, the height between the centres of top and
bottom flanges A, the strain ou the flanges k, the weight of
the structure itself p, and the niasinium load per foot
j>', while p' = A Himilar but smaller load, P = I"
luad in the centime, and P' = a smaller central load ; then
have for smaUer bridges,

For larger bridges, the foUnwing formula; are to be used, wlien —
fPk

For parabolical girders,/ = I '3456 + — J A,

For lattice girders of same section tbi'oui;!iout,/= ('2083 + --)\.

For lattice girders of varying sectional ai'ea, f = ( -25 + —^ .

^ 21-'

For a pair of girdeta loaded on one hay, / = (ue a + —)a.

'Where A signifies the relative proportion between the largest uid.
Btnallest sectional areas of the flanges."

In concluding this important subject we shall submit to our
leaders the following valvwible ^-^bi, ksA \i^ Mc David Eiric-

R»s,] KIKKALOrs EXPEEIMENTS ON IRON, 837

dy before the Institution of Engineers in Sctitland. Tlie paper
taroughout abuimds with experimental /u<;/«, and ia therefore to
be implicitly relied upon.

" Mr. Kirkalily exiiibited several oases of the fractured speci-
mens upon which hia experiments were maile ; and, by way
of introduction to the discussion, there were read from his Trea-
tise the following conclusions arriv^ed at by Mr. Kirkaldy in the
course of hie inquiry ; —

1. The breaking strain does not indicate the quality, as
hitherto assumed.

2. A high breaking strain may be due to the iron being of
superior quality, dense, fine, and moderately soft, or eimply to
its being very hard and unyielding,

3. A low breaking strain may be due to looseness oud coarse-
ness in the texture, or to extreme softness, although accompanied
by very close and fine quality.

4. The contraction of area at fracture, previously overlooked,
fonns an essential element in estimating the quality of sjie-
amena.

5. The respective merits of various specimens can be correctly
ascertained by comparing the breaking strain jointly with the
contraction of area.

6. Inferior qnaUties show a much greater variation in the
bi'eaking strain than superior.

7. Greater differences exist between small and large bars in
coarse than in fine varieties.

8. The prevailing opinion of a rough bar being stronger than
a turned one is erroneous.

9. Boiled bars are slightly hardened by being forged down.

10. The breaking strain and contraction of area of iron plates
are greater in the direction in which they are rolled than in a
transverse direction.

1 1. A very slight difference exists between apeciraena from
tha centre and specimens from the outside of crankshafts.

12. The breaking strain and contraction of area are greater in
those specimens cut lengthways out of crank-shafts than in those
cut crosBways.

13. The breaking stiiiin of steel, when taken alone, gives no
clue Ui the real (qualities of various Icin^ of that metal

r

EHCISEEBIBG FACTS.

I

15. The breakiug strain, ^'otn/Zy with the contraction of ftnia,
affurda the means of comparing the peculiarities in variuus lota
of apecimens,

16. Some descriptionH of Bteet ate found to be very hard, m
consequently, suitable for some purposes; wliiUt others are ex-
tremely soft, and equally suitable for other uses.

IT. The breaking strain and contraction of area of puddled-
steel plates, a» in iron plates, are greater in the direction in vhicli
they are rolled; whereas in (rfM^steel they are leas.

18. Iron, when fractured suddenly, presents invariaMy a crys-
talline appearance; when fcactured sluwly, its appearance is ii
variably fibrous.

19. The appearance may be changed &om fibrous to crystalline
by merely alteriiLg the shape of the specimen so as to render it
more liable to snap.

20. The appearance maybe changed by varying the treatment
so aa to render the iron harder and more liable to snap.

21. The appearance may be changed by applying the strain
B") suddenly as to render the specimen more liable to snap, from
having less time to stretch.

22. Iron is less liable to snap the more it is worked and rolled^

23. The ' skin ' or outer part of the iron is somewhat harder
than the inner part, as shown by appearance of fracture ii
and turned bars.

34. The mixed character of the scrap iron used in large fold-
ings is proved by the singularly varied appearance of the htuAxivat
of speciJaens cut out of crank-shafte.

26. The texture of various kinds of wrought iron is beautifully
developed by immersion in dilute hydrochloric acid, which, acting<
on the surrounding impurities, esposes the metallic portion alont
for examination.

36. In the fibrous fractures the threads are dmwn out, and
are viewed externally, whilst in the crystalline fractures the
threads are snapt across in clusters, and are viewed internally or
sectionally, In the latter cases Ihe fracture of the specimen is
always at right angles to the length ; in the fornior it ia more o.
le»a JiTEguW.

F

laoH.] KIEKALDyS EXPEKIMESTS OH lEO.V.

27. Steel invajialily preseot^ when fractured sktwly, a eilky
fibrous appearance; when fractured saddenly, the appeanuico i»
iiivariabt; granular, is which case also the fracture is always at
right angles to the length ; when the fntctuiu ia iibrouii, the
angle diverges, always more or less from 90 deg.

38. The granular appearance presented by steel suddenly

fractured ia nearly free of lustre, and unlike the brilliant crya-

^^allinti appearance of iron suddenly fractured; the two combined

^bi the same specimen are shown in iron bolts partly converted

^^ptb) steeL

^V 29. Steel which previously broke with a silky librous appear-
I ance is changed iuto granular by being hardened.

30. The little additional time required in testing those speci-
mens, whose rate of elongation was noted, had no injurious effect
in lessening the amount of breaking strain, as imagined by

31. The rate of elongation varies, not only extremely in dif-
ferent qualities, but also to a considerable extent in specimens of
the same brand.

32. The specimens were generally found to stretch equally
throughout their length until close upon rupture, when they,
more or less, suddenly drew out, usually at one part only, aiime-
timee at two, and, in a few exceptional cases, at three different
places.

33. The ratio of ultimate elongation may be greater in sliut
than in long bars in some descrij)tion of iron, whilst in others the
ratio is not effected by difference in the length.

3i. The lateral dimensions of specimens form an important
element in comparing either the rate of, or the nltimate, elonga-
tions — a circumstance which has been hitherto overlooked.

35. Steel is reiluced in strength by being hardened in water,
wliile the strength is vastly increased hy its being hardened in oil.

36. The more highly steel is heated (without, of course, run-
Ing the risk of being burned) the greater is the increase of strengtli,
a its being plunged into oiL
I 37. In a highly converted or hard steel, the increase i

rength and in hardnesB is greater than in a leas converted o
?t ateel.

. Heated Btee], by being plunged into oil, instead of water,

I

I

I

I

no ENGISEEKIHG FACTS. piv. VIL

not only conaiJerably hardened, hut touyhnned by the
treatment.

3d. Steel plates, hardened in oil, and joined together with
rivets, are fuUy equal in strength to an anjoint&I soft plate,
thtt loss of strength by riveting is more tlian oouuterbalanced by
the increaae in strength by hardening in oil.

40. Steel rivets, fully larger in diameter than th'jse used
riveting iron plates of the saiue thickness, being found to be
greatly too small for riveting steel plates, the probability is sug-
geateil that the proper proportion for iron rivets is not, as gen-
erally assumed, a diameter equal to the thickness of the two plates
to be joined.

41. The shearing strain of steel rivets is found to bs about a
fourth less than the tensile strain.

42. Iron bolts, case-hardened, bore a less breaking atrain than
when wholly iron, owing to the superior tenacity of the snia]l
proportion of steel being more than counterbalanced by the greater
liuetility of the remaining portion of irun.

43. IruQ hijj'hiy htahid, and Euddeuly cooled in water, ia
hardened, and the breaking Btraiu, when gradually applied,
increased, but, at the same time, it is rendered more liable to

44. Iron, like steel, ia softened, and the breaking strain
duced, hy being heated and allowed to coot slowly.

45. Iron, subjected to the oold-rolling process, has its breakisg;
strain greatly increased by being njade extremely hard, and not
by being ' consolidated,' as previously suppos

46. Specinieus cut out of a crank-sbaft are improved by addt
tional hammering.

47. The galvanizing, or tinning, of iron plates, prodi
sensible effects on plates of the thickness experimented on.
The results, however, may be different should the platt
tremely thin.

48. Tiie breaking straiu ia materially affected by the shape of
the specimeiL Thus the amount borne was much less whi
diameter was uniform for some inches of the length than when
confined to a small portion — a peculiarity previously
tainad, and not even aus^xitted.

49. Jtianecasaary tokfitiwtMTieii'is'CttaesMai'

li[os.] KIEICALDVH EXPERIMENTS ON IRON. 941

which any tests are madB, before we can oijuitably mimpaie resulti
cihtained from different quajtere.

50. Tiie startling discrepancy between experiments made at
tlie Royal Arsenal, and by tlie writer, is due to the difference in
the shape of the respective specimens, and not in the diSt^renct'
ill the two testing machines.

51. In screwed bolts, the breaking strain is found to be greater
irhi^Ti old dies are used in their formation than when the dies are
new, owing to the iron becoming harder by the greater pressure
required in forming the screw thread when the dies are old an.!
hlunt, than when new and sharp.

52. The strength of acrew-holts is found to be in proportion
to their relative areaa, there being only a slight difference in favour
of the smaller, compared with the larger, sizes, instead of the very
material ciifferonce previously imagined

53. Screwed bolts are not necessarily injured, although straineil
nearly to their breaking point.

54. A great variation consists in the strength of iron bara which
have hum cut and welded; while BOme hear almodt as much as
the uncut har, the strength of others is reduced fully a third

55. The weldingofsteel bars, owingtotheirheingso easily bullied
liy fihglitly overheating, is a difficult and uncertain operation.

56. Iron is injured by being brought to a white or welding
heat, if not at the same time hammered or rolled

57. The breaking strain is cunsiderahly lesa when the strain is
applied suddenly, instead of gradually, though some have ima-
gined that the leverse is the case.

58. The contraction of area is also less when the strain is
suddenly applied.

59. The breaking strain is reduced when the iron is fi'ozen ;
with the strain gradually apphed, the difference between a frozen
and unfrozen bolt is lessened, as the iron is warmed by the draw-
ing out of the specimen.

60. The amount of heat developed is considerable when the
specimen is suddenly stretched, as shown in the formation of
vapour from the melting of the layer of ice in one of the speci-
mens, and also by the surface of others assuming tints of various
ahailes of blue and orange, not oidy in steel, but also, alth(

in a less marked degree, in iron.

1

^■p EN-GIN'EEKING FACTS. [Dtv. V[I,

61. The specific gravity is found generally to indicate ptetty
correctly the quality of apecimena

62. Tlie density of iron is decreatfd by tlie process of wire-
drawing, and by the similar process of cold-rolling, instead of

^mSnereamJ, aa previously imagined.

^B 63. The density in some descriptions of iron is also decreased

^mj aiiditional hot-roUing in the ordinery way; in others tliB

^Bensity is very slightly increased.

^m di. The density of iron is decreased by being drawn out umlet

^h tensile etraiu, instead of increased, a.=i believed by some.

■ 65, The most highly converted steel doos no^ as some may
Bnppo.%, possess the greatest density.

66. In cast steel the density is ranch greater than in pnddied
steel, which is even less than in some of the sapcrior descnptiona
of wrought iron.

" The breaking strain per srinare inch of wrought iron is gener-
ally stated to be about 25 tons for bars and 30 tons for plates.
This corresponds very nearly with the results of the writer's ex-

Iperiments, of which the following table presents a iMinden^oiI
inmniary :^
opi

i, rolled, fl8,S48 14.584 S7,6S6 = Sid]

jE-inin, &c., 63,715 87,809 6i,7S9 =241

167 Plates, langthwHjs, 63,544 37,474 60,737 |_-,,

160 Plates, croamavs, 60,756 32,450 46,171 j — "m

" Although the breaJcing strain is generally assumed to be alwut
i tons for bai9 and 20 tons for plates, very great difference of
1 opinion exists as to the amount of worh'ng strain, or the load
which can with safety be applied in actual practice. The latter
is variously stated at from a third to a tentK It will be observed
that whilst much disuussion has arisen aa to the amount of work-
ing strain, or the ratio the load should bear to the breaking
strain, the important circumstance of the quality of the iron as
influencing the working strain, or the ratio the load should bear
to the breaking strain, the important circumstance of the gvali'i/
lithe iron, as influencing the working strain, has been overlooked,
^e fioard of Trade limits t\ie attoia to five tons, or 1 1,200 lbs.
V^nare incn.

BREAKING AND WOHKIHG STRAIK OF IRON.

It must be abundantly eviilent, from tlie facts which have

been produced, that the breaking strain, wlien taken aiona, gives

a false impression of, instead of indicating, the real quality of

t!ie iron, as the experiments which hare been instituted reveal

the somewhat etarthng fact, that frequently the inferior kinda of

iron actuaUy yield a, higheT result than the superior. The reason

of this difference was shown to be due to the fact, that whilst

quaKty retained its original area, only vtiy alightly de-

by the strain, the other was reduced to less than one-

Now, surely tbia variation, hitherto unaccountably com-

rtely overlookt'd, is of importance, as indicating the relative

or softness of the material, and thus, it is submitted,

essential element in conBtderiiig the safe liuid that can

practically applied in various structures. It must be bomo

mind that although the softness of the material haa the effoct

lessening the amount of the breaking strain, it has the very

iposite effect as regards the working strain. This holds good

,s : first, the softer the iron the less liable it is to

ip; and, second, fine or soft iron, being more uniform in

"Ity, can be more depended upon in practice. Hence the load

ih tluB description of iron can suapend with safety may aiv-

!h much more nearly the limit of its breaking strain than

be attempted with the hnnler or coarser sorts, where a great

margin must necessarily he left.

" Special attention is now solicited to the practical use that
may be made of the new mode of comparison introduced by the
writer, viz. : the hreakivg strain per square inch of the nuoirRED
rea of the specimen, instead of the breaking strain per equare
of the ORIGINAL area.

Am a necessary corollary to what ha has juat endeavoured to

iblish, the writer now submita, in addition, that the workiug

should be in proportion to the breaking strain per square

inch of fractured area, and not to the breaking strain per square

inch of original area, as heretofore. He does not presume to say

what that ratio should be, but he fully maintains that some kinds

of iron experimented on by him will suatain with safety more than

luble the load that others can suspend, especially in circumstances

'here the load is unsteady, and the structure exposed to concus-

abip, or to vibratory action, u m % n.Uwa.^ ttcidt;^

area
^ftdiat

ENGINEEKINC FACTS, [Div. VH.

^1 " The writer baa not attempted to expkia the cause of the

^B mysterious chosge produred on steel by heating it and plusgiDg

^B it into water, or the no lesser singular result effected by plunging

^f it, when heated, into oil. Neither has he tried to account fir

the mysterious change produced by subjecting iron to the pro-

ceaaes of cold-rolling or wire-drawii^. The explanation offered

by some, of this difficult question, that the iron or steel are eoii-

Pden^ by the processes to which tliey are subjected, is completely
oonttadicted by fact, the metal being actually expanded. The
aim of the writer being strictly to ascertnin facts, and stale the
conclusions which he considers to be iairly deducible from them,
he has not felt himself warranted in attempting to speculate
a subject respecting which so little is yet known.

" In conclusion, the writer ventures only to express a hope tliat

P^ the experiments, on which he haa been so long and unremittingly
eiigageii, may not prove wholly unserviceable to practical aoience
»nd the world at large. The im]>urtance of possessing a thorongh
knowledge of the capabilities and strength of substances t
which the livea and property of bo many human beingg iJepemi,
no one will attempt to deny. TJie only excuse, ii^ indeed, e
cuse it can be called, for employing an inferior description

» material in the rearing of litructures on the abability of which
Buch momentous issues are involved, is ignorance or misappre-
hension of its proper quality. The writer has endeavoured, by
a plain statement of iact^ to furnish some information on a sub-
ject which seems, until now, to have been denied the attention
which its paramount importance demands. Were this question
fairly taken up and considered, some security might be afforded
^^ against the repetition, in future, of disasters occasioned by its
^L being so often practically ignored The necessity of using n
^^Vthing but the very beat description of metal, where human li
^^Bor valuable property ia at stake, may, he tnista, come aoon to be
^H More generally recogiuzed than it is at present. And an increased
^V demand for the tiner varieties may conduce to a genorous emulation
^H| amoDgat the manufacturers to improve still further the quality of
^H their production!^. Should his labours tend in any way, even the
^H smallest degree, to diminish the annual sacrifice of life and pn>-
^V pvit^ occasioned by faulty material and workmanship, lie will feel

ACTION OF WATER AHD OIL OS STEEL

-. KirkaUly exhibited 490 selected apecimetis, wliiuli v
mtaiued in iive cases, SEUuely: —

^ Case I. 9 ii-oD bars, showing elongfttion mid lalTal ci

1 iron p1at«, ditto.

1 bUijI plate, ditto.

h Case 11. a steel bars, showing fiafluns and contraction or uea.

I lOS iron bars, ditto.

^ Case III. 36 steel platea, ditto.

BO iron plstea, ditto.

24 angle-iron. 4«., ditto.

^ Caae 17, S6 iron liars, showing fractures and efferta of ditforence of

suuuciiiy I

4

12 steel bars, ditta
10 iron plat^ ditto.

IG iron bars, showing frsctares mid elTvct« of strains suddenly
and gradually applied.
i C>H T. W iron bias, showing fractures of screwed bolts.
12 iron bars, showing frictnrea of welded joints.
B steel bars, ditto.
2S iron bare, showing texturii as deFelojied by oi
6 iron plates, Jitto.
1 iron plate, wtb surfacE cold-railed.
i iron bars, with snrfaoe eold-rolled.
" In the discuseion which followed —

" Mr. Walter Macfarlane said it was well known to all prac-
J workera in steel and iron, that if they attempted to temper
roe kinds uf steel articles in water they cracked ; but that if they
ame thing in oil there wiia not the same danger of doing
He did not know whuther Mr. Kirkaldy had givnn, or coulil
low give, an explanation of the cause of the increased strength
if Bteel when tempered in oil, aa compared with that tempered
B water 1 He wouhl like to know whether the fibi* altered,
IT what tended to produce tlie result.

> " Dr. Macquoru liankine remarked, that Mr, KJrkalily dia-
itrowed in hia book any attempt to explain the changes which
»k place in steel when plunged into water or into oil.
"Mr. Macfarlane saidhe thought there was an abaolutenecEBaity
ir their getting at the cause of that important result.
" Mr. Kirkaldy, in answer to the president, had nothing fur-
r to say upon the point.

"Mr. D. More said that Mr. Kirkalily invited 'special atton-
a to the jirnftiuil use that ma; he m^de of the new mode u'

mode t^ J

to be
■ Jfow,

^■irokei
"^was si

mue ENGINEERING FACTS. [Div. Vll.

' eoiupui^on introduoed by Liin, viz. : the breaking gtrain per
square inch of the fractured area of the gpecimen, imttead of tlie
breakitig strain per equare inch of the originai area.' Thataeemed
to be the principal point hinged upon, as it woa given in italic*.

i Jfow, be did not think it was even the hreaking strain of the
'mctiirr-d area that must bo considered, fur after the iron was
roken it drew out a little further. This sort of posterior action

^ was shown in some experiments made by Dr. Eonkint and him-
self in regard to iron and also brick They found, in crushing
the brick, that it withstood a considerable firce, and afterwards
crumbled away with a less foree, th;i3 showing that the breaka^
had really taken place before the brick bad eommenced to crum-
ble away. In experimenting with an iron bar, it was observed
that the iron drew out and became narrower at one part (as he
showed by a sketch on the board) until the strength of the material
was overcome. Then, immediately on the iron beginning to
break, it drew out before it was finally completely separated, so
that the fracture took plac« when the bar was a little bigger than

I it lindly became. He thought that the ttuth lay between the
'wo areas — the original and the fractured area.

" Mr. Kirkaldy said he had given tlie stretched area also in his
tables, so that parties could judge of it for themselves. The three
re given — the original, the stretched, and thefracturedareas.
" Mr. W. M. Neilson reraarked that Mr. Kirkaldy's book was
I mass of dfafu &om which to deduce results. He thought it
was a very excellent thing that Mr. Kirkaldy had confined him-
self to giving facts, wliich would cause his book to be much
more relied upon. He believed that Mr. Kirkaldy wished to lay

this facts before the Institution for discussion, and that he would
not be displeased, although they pulled them about as they liked.
Etegarding the effects of frost upon iron, upon which point he
had never Idmself been quite clear, it appeared that frost did
not affect the strength in a direct strain ; but he had always had
an idea, that perhaps not the drawing strain, but the breaking
stntin, was very much affected by frost They ail knew the fear
they had of using chains in frosty weather. Now, he supposed
that the strength of the chain links was very mucli diminished
hy tbe frost, and that the links broke not so much by tUrect
teaaiou M by A breaking attun.

INFLUEKCE OF FBOST OS IROS.

" Mr Rirkaldy said lii^ experituenta on the iullai
were all mtule with apecimens taken frum one bar. He reffretted
that the weather changed before he could carry out hia intention
of repeating those experiments with bars of various qualities.
As the bar experimonted upon happened to be of very good
quality, perha,p8 they ought not to draw general concluaiona from
its behaviour.

" Mr. W. Simons said that in the operations attending upon
the placing of a thousand-ton ship on a ehip-dock, during one
frosty niglit he had seen three rods 3J inches in diameter, broken,
au that they had to stop and pnt fire to all the rods and joints,
and after that none of the rods broka In the International Ex-
hibition, he had observed a very good specimen of Swedish iron,
which some of the other members might also have seen, which
yras all crumpled like a hat, it being the bow of a steamer after
collision. He did not believe that any Scotch iron would have
stood such a test. He was of opinion that the result of Mr.
K irkaldy's investigations would be, that the present system of
^^&ip-building would be found to be entirely erroneous, and that
^^br the future iron would be used in ship-huilding with ita lon-
^Bntndinal £bre placed in the direction of the roost constant
^^ftiain, a principle which had hitherto been ignored in marine
construction.

" Mr. B, Connor said that some very interesting experiments,
which had not been published, had been recently made by
Messrs. Naylor and Vickers, at Sheffield, with a view of testing
steel, so as to ascertain the best suited for railway axles and tyres.
I They had found that the material best suited for axles was the
^Bworst for standing great tension. Tliey found that steel, which
^BOuId bear only 35 tons of tension, was tlie best for journals.
^Khe; tried steel with 15 cwt. falling from 1 ft. np to 36 a The
^^Rensional strength of the steel was then increased so as to stand
^H^) to 69 or 70 tons, but it broke with the weight falling one-
^BBkird of the space, and with less than one-half of the weight ;
^^KBd BO that that which stood the greatest tension broke with the
^^fcaet concussion. He thought that between the highest and
^Hbe lowest quaUties of steel there was only a difference of one-
^^feurth per cent, of carbon.
^^y^jtfr. Xirfcaidy thought that theae ex^'n.m<9TA& a'^.'^^Ual Kteon^ )

I

ENGINEEHISG facts. [Div. vii.

nasTiDS for takiug the stretched and fi'actureJ areas luto account.

B. Connor did not think the steel with the greatest

Moount of carbon, that broke almost short off, would show nearly

great a Jifferenoe between the fi'actured and tlie original areas

the soft flt«eL

" Dr. Maoquom Rankine concurred in what Mr. "W. M. Neil-
iBOn had said as to the very yaluahle ci>llectiou of facts^ moat of
itliem entirely new, which Mr. Kirkaldy had given in his book.
It was a storehouse, from whicli they could all draw materials,
■nd form their own concluaiona upon thein. Mr. Kirkaldy had
Tery fairly described those facta, and it was the better that he had
not set up any hypothesis upon them. One of the particular things
wliich he (Dr. Knnkine) remarked was, that the experiments of
Hr. Kirkaldy seemed to point to the conclusion, that a process
which many supposed to take place, namely, a change from the
fibrous to the crystalline struotiire, had no real esistenoe; and
that the same piece of iron would show a crystalline or librons
appearance accordingly as it was broken by a stroke or a stmn.
li^ gam^ to the same concliisii>ii himself uiaeteen jeara ago by
experimenting on the fracture of railway axles, which when fitted
id to have been quite strong enough. He collected thu
broken-off journals of such axles j but he was sorry that he could
produce them, as no means had been taken to prevent
[Hhe ends getting rusty. Bat he had made full-aized drawings,
oolonred from nature, of the more remarkable of them, which he
presented to the Institution of Civil Engineers, along with a
paper, an abstract of which was published; but the drawings
were not pubhshed, and remained at that Instttution, where they
could be seen by any one. He still, however, possessed the ori-
ginals of those drawings; and if it would be agreeable to this In-
•titution to see them, he would produce them at a future meeting.
""" courrw they were not so satis&ctory as the original specimens,
Mr. Kirkaldy's; but unfortunately the originals had been
ipoiled by tust He got the journals of axles that had run two
iliree years, and had then broken off spontaneously, and almost
■ery one of these showed a fibrous fracture, with here and there
crystalline spot. There was invariably a crack which had eaten
(rom the shoulder of the journal, and which was perfectly ini-
'tibia until after the iractuw UioV 'j'Uce, 1\ia t-tat^

liiiiK.] BKEAKING STRAIX ASD FRACTURED AREA OF IBOS. U9

to have gone on until it had reduce the nriginol Jintueter of the
journal to about one-hal^ and then the axle snapped; bat it al-
ways presented a fibrous fracture, whilst if the same joumftls were
broken off with a blow of a hammer, thej presented crystalline
or graonlar fractures. Accordingly, he had ever aince thought it
proliable that a ohanga from fibrous to crystalline, as supposed,
was an erroneouB hypothesis ; and he believed that many othi;r
perwns bad come to the same opinion, and he was glad that Mr.
Kirkaldy's experiments corroborated it. An important point in
those experiments was the calling attention to the comparisoit
between the fractured area and the load that caused the piece to
give way. Every one knew before, that bare of iron would draw
out, especially if soft, before giving way ; but never before Mr
Kirkaldy had any one accurately measured the final area to com-
ic that with the load. He thought that there was a great deal
the principle Mr. Eirkaldy laid down as to testing the quality
iron, by the comparison of the breaking strain with the frac-
area; but be would not go so far as Mr. Kirkaldy and eay
tibat it woa the mo^t accurate teet, although he hod uv doubt it
waa better than comparing the original area with the breaking
load. The experiments of Mr. KirkaJdy had substantiated results
that had been anticipated by theory. For example, it was a re-
sult of theory that the form of the longitudinal section influenced
the breaking load per inch of area. Experimentalists, however,
had not taken that into consideration before. Experiments were
made upon the tenacity of bars that were for a long distance of
a uniform diameter, but there had been experiments made with
bars shaped so as to have an increasing diameter on both sides
.ot the middle part (as he pointed out on the board), and the re-
It was a great apparent increase of strength. It had been
fectly well undeistood by writers on t!ie theory of elasticity,
lat the shape referred to must give apparent increased strength
to the narrow portion of the area, as the wider parts on each side
resisted the tendency to draw out, which was not the case with
the parallel bar. Experimentalists, however, had not taken this
into account until Mr Kirkaldy took it up and arrived at the
results detailed in his book. Mr. Kirkaldy showed that the re-
sistance of steel rivets tu shearing was about a quarter less than
tb» teaaei^ of the sleeL That, also, was anticipated by tlieory, |

^rfth
■talt
Kbrfe
P&iat

F

Mr. ]

Bof th

per I

inch

■ ^Baen

■rteel
■»tit

Lnrnt
We

ENGINEEBISG FACTS. {Dn: Til,

There was one very imputtant point upon wUiuh Mr. Eirkaldj'
made some remarks, namely, as to tbe iactor of safety — the reHu
ju wliich the breaking load oiiglit to exceed the working load.
Mr. Eirkaldy considered that the wurhing load per square inch
9f the original area of the piece should be a certain percentage
~ the breaking load per squure inch of the contracted area at the
,nt of being broken. He (Dr. Ranldiie) concurred in 1~
More's opinion, that the truth lay between the extreme views.
thought it would be going rather too far to make the working load
per square inch a certain fraction of the breaking load per square
inch of the fractured area. He might call attention to experi-
i the strength of steel by Pro£ Tresca, of the French
ivernment Corps of Engineers. Tliey were made upon bars of
el cut out of boiler plates, and tliey showed tho gradual elou-
gSition of the bar with the gradual increase of the load. Xh"
TBBults were represented hy a curve (of a kind sketched on the
board by Dr. Kankine), the abacissea of which represented the
load^ whilst the oidinates represented the elongations due to the
loads, It was found that as the loard woa increased, the elonga-
tion increased at a uniform rate, until it reached a certain point,
when there occurred a great increase in the rate of elongation,
which was not quite sudden, though nearly soj and there resulted
a curve, the early part of which proceeded in a nearly uniform
direction, and which merged by a quick bend into a portion pro-
ceeding in a different direction corresponding to the more rapid
elougation, Now, he thought the point where the change in. the
curve of elongation occurred was that at which the strength of
the material had been overcome. It was very probable that the
drawing out, which was so conspicuous iu Mr. Kirkaldy's expe-
lents, began at that point, and that the greatly-increased curve
elongation showed that tlie breaking had begun, and that the
would break if the same load was simply put on it several
times, without being increased, as was seen in Mr. Fairiiairu's
esperiments. The experiments of this class were very interesting,
taken in connection with Mr. Kirkaldy's experiments. He
.thought, then, that the best test of the quality of the material
avas the strain at which the sudden change of the curve of elon-
jjation began ; or, if that supposition of bis was right, the point
*■ wJiieb UiB ^wing out oS ft\e ffimsa c^tKa»a»A. ^jM^Mii

WEiEB.] STRENGTH OF IKON— TIMBER.

I^^OuM auly make experiments so precisely as to measure the niva
' n{ the bar at the instant of change, and compare it with the luiul,
aiid take the corresponding strain per square ineh, the; would'
get at the true strength of the material ; it would give a result
between that of the old method and that of Mr, Kirkaldy's
methoii But although it was very desirable to obtuin such ex-
periments, yet there were difficulties in the way of perforniiug
them upon the immense number of materials that Mr, Kirkaldy ,
had experimented spun. The Institution could not be too '
gratefiU to him for hia labours, for he had collected a mass of
I facts which were of the highest value in a scientific and practical ]
^n»int of view." ^^^^J

^H DIVISION EIGIITH. ^^^|

On the properties of timber and wood, the following is u i
thoroughly practical paper by Joseph Justen, which we extract
from the 'Builder:' —

" By wood we understand that portion of a tree between the ,
rind and the marrow, and we have to distinguish the heart from
the sap wood. In hotter climates trees generally grow largest.
A. piece of lieart wood is heavier and harder than a piece of sap
wood, and a piece cut from near the root will be heavier and
stronger than a piece cut from near the top.

" The size to which some trees grow is astonishing, A few
famous cheanut trees on Mount Etna measure irom 60 to 80
feet in circumference: near Worms, in Ciermany, grows an elm
tree (Ulmus campeeti-ia), called the Luther tree, 116 feet high
and 35 feet in circumference : on the island of Teneriffe, a draeasiia
(<lragon tree^ is seen, 80 feet high with a diameter of 29 feet.
Still larger than these are the mammoth trees {Wetiingionia
ffigantea), and the firs, found in America, some of which are

Iinported to measure 400 feet in height and from 60 to 80 feet
In circumference.
L "The inner structure uf trees is the foundation of all Dm ,

ESGINEEIUNG FACTS,

^K Bingularities of the wooda. It is tbe sBme in most EiiTOpeau
^H Slid other trees. If we look with the assistance of a niaguifying-
^^B glass at a cross section, we obaervc in the centre the
^^P next to it the heart wood, then tlie sap wood, the cambium, and
I the bark. From tho marrow run out towards the rind thin

lines, which ai'e crossed by riogs, taking the appearance of tha
cobweb of a spider. These rings indicate the age of a tree, one
' being in general added every year. Some trees live very long:

I for iustance, the Adansonian, standing on the banks of the Sene-
gal, is estimated to count nearly 6,000 years.
" The yearly rings stand in close connexion with the develop-
ment of the leaves : if we find them imperfect, it bos been caused
by the loss or the freezing of the branches. It might also have
been eflfect«d by dryness, or by insects and larger animals who
Uve upon and in the trees. Among the most destructive in thfl
animal kingdom whioh attack trees are enumerated the cock-
chafer, hornheetle, the barkscrab, tlie castor, hai'ea, rabbits,
squirrels, and deer. In some instances it bas been found that
the August sap forms in the same year a second ring, by which
the age of a larger tree becomes doubtful if it is estimated ttom
its yearly rings. Tbe formation of these rings is not so clearly
marked in the wood which has grown in hotter climates.

t strange appearaaoe is caused by the unequal width of the" rings,
and in fact it is never that two of them are found alike, o
least very seldom. Tlii? feature, is, however, of valuer because
one may judge by it upon the physical condition of the wood;
and we will, therefore, examine this point more closely.
" The fir, which grows on very dry marl, forms very namw
yearly rings ; if on rich or damp marl, they are wide; and when
on wet soil, they are agiiiu smaller,
soil, has even smaller yearly rings than if on dry sand or marl.
j^Froni this it is evident that too wet or too dry a soil ie not suit-
i|, timlP for the promotion of this tree.

experiihs alder {BetiHa tdniis), the willow (Salix), and partly,
taken in coV ^f^e {Fratcinvs), grow heat on wet soil, and tlmv&
thought, then, tP standing dry.
1. was the strain at Jife of a tree requires a certain amount of light
[Stion began ■ or iif^^i ""bic^i ihb isacesaary, besides the noMriah-

GROWTH OF TIMBER- SSS

kneferred iiito a mora suitable climate or liolier soil, it will

ally improve in condition ; but should any element be de-

mt, we ahall notice no improvement, or tlie tree may impriDve

B way, such aa inereaae in size, while it suffers on the otlipr

lldj for instance, loses in its specific weight. A pine witli

pU yearly rings is of good quality, for we Snd each apring la'

mer ring surrounded with riptr autumn wood, richly eatur-

f Towards the bark the autumn rings remain about the same

\aeaa, whilst the softer portions are seen larger. A white

!, twenty-five years old, and situate in a tolerably suitable

I, may have a diameter of 3 inches or more, whilst another

(dry ground will be but 1 inch tliick. With the former the

jrly rings will bo 25 mill., and with the latter 0*16 mill. If

■■Hubrait a cross section of each under the microscope the for-

• will appear like a net with large pores, while the second

bs almost like one solid mass. This fact iUustratea the cause

■ 11)6 many accidents which have not their immediate origin

i'the lutten or bud state of tiiuliers. Ttie grcateat attention

uld be pajd to the pnint in the selection of masts and spars

hip-building yards. The usual width of the rings in the fir,

L young, is 3'4 mill, with a slight decrease towards the

; the smallest rings are found in the Sweiiish and Russian

: this may be ascribed to the short summer in those climates ;

' Bv are found similar in more southern climatea:

refore the same result is brought furward under different cir-

" The leafwoods with large pores deserve special observation,
s but opposite to those made with the pines, we notieu
k them that, although the rings become smaller, yet the qtiau-
y or bulk of the porous sjjring wood does not diminish "t the
nte ratio; therefore, a uubic inch must contain more mass the
' pores in the same; or, in other words, the broader
e yearly rings, so much greater will be the mass of the wood ;
ison is, that the pores are considerably smaller on trees with
r yearly rings, and at the same time leas numerous. Thu
r rings of trees are often found almost bb porous aa the root-
Tliis is atiU more frequently the case with the branches of
aea. 1£ we havejthe^fore, to select between two oaks, wa

I

ENOINPEItING FACTS. fDiv. Vlll. |

shall choose the one with the bruoder yearly Hngs, because we
Khali have in a cuhic foot of tlie same a lai'ger quantity of wood
tlian in the other.

" Should it so happen that a whole forest produces trees with
wide yearly rings, and another forest treea with small rings, then
the question arisea whether the former is caused by the wet con-
dition of the soil ; in which atse the wood in the fii'st will ho
mure porous and loose than in the latter. We must, therefore,
take into conaideration the specific wuight, as well as the browl-
nt^BS of the ringa ; and if we find both correspond, theii we may
conclude that the timber is sound. Wood that has rings of more
than 6 mill, wide for a section of some inches, should not be
used in building; it is only fit to be bumed. Trses which
have grown in marsh or clammy soil, along rivers, ftimish bad
timber.

" If we dissect the stem uf a tree throughout, and notice the
yearly rings, we find many divereions, for tlie explanation of
which wa have to refer to the organigation of the growth of tlis
tree.

" In pines we find more i-egulaiity in the width of tha rings,
from tha centre towards the hark ; this pmcttss depends much
upon the position of the tree and tlie surrounding influenoee.
With loafwoods we lind a greater variety in the rings, but the^
as well as the pine have that same feature in common, that ttin
rings increase towards the bark, and that close to the latter they
decrease again. The number of branches influence the width of
the rings in iheir position; and if a stem was cut tlirongh in its
centre, we might then form the relative width of the rings in
the various heiRhts, and come to a conclusion as to the cause uf
their changes. It is necessary to remark, that the assertion that
the rings are wider on the south side of a tree than those on the
north, is devoid of all truth; still, eccentric trees have broader
rings on the projecting side than on the flat side ; also inclined
stums and branches show them smaller on the upper side. The
biirk is of importance to a tree ; it acts as a protective band for
the distribution of the sap, and is therefore necessary for the
formation of the yearly rings. If the hark is damaged or split
in a certain place, we observe that the next following ring in-
vreaaea conadeiMy at this wovutA; a.^ Bs.i»:YV\w\ f^ "Oro* w. the

R.j

SAP-WOOD IN TIMBEK-

aimond tree {Amygdaluv), which beuda hollow in the place whew
the bark has be«ii damaged.

" If we turn our attention to the condition of the woods, n
tafce a cross section of the atem half an inch tliick, it will liardly
be possible to detect any difference between the younger aud the
older wood. If we take a stem of the same wood about as thick
as an arm, the centre portion wiU appear dryer and luay be called
Lha ripe wood, while the outer portion is cliarged more with sap,

i called sap-wood. With many timbers the heart-wood in of
• deeper colour, or between the ripe wood and the sapwood is a
a of different colour.

" The ripe wood absorbs water less than the sap-wood: it has
bgreater durability, and it is not so easily decomposed as the

f " In some trees the destruction commences with the ripening
f the wood ; for instance, the Canadian poplar {Populue) and

e willows (Salix), which begin to darken in the centre ; aud
f their smell they indicate tjieir decay,
' " The aap-wogd of ban! wuwi tr«us ie uf little use ; it never

a for auy period ; aud when used it only serves to introduce
estmotiTe organs into the butter wooii

" When trees arrive at a certain age they should be out down,
Fit is intended that their wood should be of good and durable

ftlity. If they ata left growing the quantity of wood will cer-
Binly increase, but the quality will suffer.

" The limits of the period when t)ie trees are to be felled Je-
jends upon the development of their wood.

" The colour is a prominent feature, not only with the various

ecies, but also ui the quality of the wood If the tree is felled
. rainy or damp atmosphere, for instance, during a mild
rinter season, then the heart of the wood will retain its natural
yet colour for a longer period. In a dry spring atmosphere the
heart-wood dries sooner, although the sap-wood retains its mois-
ture longer than the ripe wood of the atem : by this latter pro-
cess the moisture evaporates and draws towards the bark, by
which the sap-wood takes the darker colour of the ripe wood.
LThe proper colours of the various woods are only fully developed
T they have been exposed to the inHueuce of the atmosphere
B time. The time when the timber is highejst in colour j

^ tecL

ESOISEKEISG FACTS. [Div, VUl.

to be liiuiny the [leiioii whea the tree ia iu full bloom,

ich asscrUoa has, howerer, not yet been fully venfied.

" If the colour of an oak is of one cast, it is a Edge of its good

iditinn; but it must be of llie same ehade in the ripe wood

rell as in the various yearly lings: as the shades atand under

influence of action fe>m without, a proper judgment upon

condition of the wood can only be given when the tree is

tbrested. In s<>me inatanoes the scent of woods emiblos vs to

pass a judgment upon their condition. Persons who pass in the

lirst spring month a number of old white poplar trees {Popaius

'dba), will notice an obnoxious srael!: this proceeds from tlie

sap, wiiioh flows from the decayed interior to the outaida The

pine wood will retiuu its natural smell for years. Leafwood

have generally a aour smell, and it is reckoned that the

stronger it is the healthier h the wood. Should this smell be

' int we may jndge tiiat the tree is dj'iug ofE

" The Bap which circulates in the tree and promotes its life ia
ipoaod in its main portion, of oxygen, hydrogen, carbon, n
trogen, ami sulphur. The Bame forma a considerable body in the
green or fieah wood ; it changes more or less in the qualify of
the wood, and the intimate study of its infl.uencea is of gre«t
technical importance. It has been said that ^e sap flows out
' a tree after it is cut down. From experiments which liave
' ; resulted in thia being the cose with very few
'ooda, and not with the majority ; with most of them the mois-
ture evaporates.

" The quantity of sap changes very oonsiderably during the

season of the year. In elucidation of this a fine example i

furnished to ua by M. Duhamel de Moncean, and described i:

■k, ' Exploitetion des Bois.' During the years 1732 and

733 he felled each mouth eight oaks of equal age, and from

same spot. These were cut immediately into twenty-fiv9

ies, each 3 feet long and 3 inches square (Paris n

obtained the following results : —

340718 pounds (Pu

8 weight)

n Decomber.

8(0 'B06 „

January.

328-031 ..

February.

331 -087 „

March.

311 '876 „

April.

SAP IN Till HER,

2B7-3ia .,

Juuf.

397-250 „

8HM9 „

308-876 „

Oelober.

331-000 „

(Que pound Pa

I " From these figures it a,ppefLTS tiiat, during the months of
^rnber and January, the trees contain more sap than at any
other period. It diminishes in October, Novemher, February,
and March ; next in April, May, August, and September ; and
its quantity is least during the months of June anil July.
, "From another experiment, made in 1737-38 with six stems
t young oaks, it -was aacettatned that the lower portion of the
ffvik weighed (hydrostatioally determined) of the December
" ", 1-132; Aiiril wood, 1-016; July wood, 1-017.

"Thia proves that there was most sap in the December wood.
pe difference between the April and July woods remains
^btfuh The same pieces of wood were also weighed wht'ii
■, and, compared with the fresh weight, it gave tlie follow-
g tesnlt in lb, weight : —

April wood

July wood

DeuBuiber wood . , .

Dry.

2-S75

'- " Thia shows that the quantity is most in December, and le
fi July and August We must not overlook in these cases
~ e into eonaideration the iniluence of dry and wet seasons, by
fcich the sap is materially affected. Contrary to the preceding
teperiments, the notion prevails that the quantity of sap in a
re in the spring than at any other season. Another
author, Mr. Th. Hartig, found, after many experiments (wliicli
are fully described in Nordlinger's 'Technical Properties of
Woods'), that, upon the average, with most woods the greatest
_nioiBture is in trees during the mouths of January and February.
B reckons it at 6005 per cent. During t!ie months of March
iod April some trees discharge through their bark a quantity of
^ liom whidi cme should believe that they were full uf it*

ENGINEERING FACTS. [Drv. VIU.

r«hile only 475 per cent. U itially in tlic'in. lii May aiid June

Lllioy bold 48 5 per cent. ; in July, during which the yearly ting

"s tiirineii, 50 per cenL ; and in Septemljer, when the ring is fuliy

icloped, they ooiilaiu 48 per cent.

" ITie large amount of sap which is fuund in stems during the
■inter monthB diminishee towards the spring.

" Heavy hanl woods lose by drying alwut one-thini of theit

original weight : lighter woods, iroplars, alders, pines, &e., lose

Hfiom one-third to one-half, wtiieh in some degree is dependent

#Tipoii the soil where they were grown. The bark prevents the

r«ap from running ont of the stem ; therefore, if pieces were ta."

from the same stem, some with and others without the bark

it will be noticed th.tt those without bark will discharge much

quicker than the latter. Experiments have also proved that the

weight of pieces with their bark on fluctuates, whilst the weight

of barked wood steadily diminishes. The cause of this difference

is most probably due to the hygroscopity of the bark to absorb

humidity from the atmosphere.

"Wood never loaea all its sap: when it becomes air^dry it
generally has about 20 per cent, of its weight. It is of impor-
tance to know how long various timbers of diU'erent dimensions
and strengths will take to become air-dry ; that is to eay, how
aoifu will they arrive at the medium weight which they always
maintain, and to which they return whenever the influence of
the atmosphere alters it,

" Many mechanics require dry wood for their work, but it is
not seldom that they use it before it is properly seasoiied.

" I have before alluded to several instances which affect the
line seasoning of timber, and from these it is impossible to adopt
it general rule, because in each place surroanding influences must
be taken into consideration. Let me, however, refer to the cause
of the warping of floor-planks, which has its reaann, — that the
air does nut leach the lower side of the deal. It shows ilselt
i^tronger where the plank has been planed at the top and the
lower side has been left in its rough state, by which a largi^r
quantity of moisture is discharged by the outer side, which causes
tliB warping.

" In exposing various woods to the action of water, it wUl bo
J'ouuii th&t the younger atenw ».» naoTftBii!iiiwij<ASft"\S»Sna«ja«afc,

R-]

DEtrSITY OF TIMBtB.

! it absorbs more water than old wood. For Lj'draiilic
HistructionE, noae but well seasoned old hard wooda shoaM be ■

; and the sap wood ahould also be avoided, because it pro-
10168 the decay of the Bound parts. The specific weight miift
t be taken into consideration.

" Moat of the woods swim in water. The specilic weight
[ wood is found by taking the dry weight, then thrown intti
tater until quite saturated, after which it is weighed again. We
Bust then weigh it under water, If we then divide with the
ifferepce of the second and third weights, which represent the
ight of the water displaced by the wood, into the natural dry
weight, we obtain the specific weight. This answers in general
well enough, but it is not ao correct as the process recommendeil
by Mr, Marciia Bu!L He justly observea that the wood is liable
__to swell in the water ; and after having token the dry weight he
jrered the piece of wood with a varnish having the exact
isity of the water. Tliis varnish is composed of rosin haviug
Ldenaity of 1 079, and wax having a density of 0'967. By this

ish the water cannot penetrate into the wood.
I " The aohd matter uf the wood divested of all cavities is heavier
n water, and its density or weight, compared with that of
pater, varies, according to Eumford, from 1*46 to 1'63,
; " It is very difficult to give a general figure for the specific
Ifeight of anykiudof wood. Pieces fi-om the same tree produce dif-
rent results, but the following figures give an average weight : — i
Ironwood
Greenheart
Sabacua wood
Bniil wood
EboQY
Box .

^T

ENOISEEItlKG FACTS, [Div VIII.

Fopl»r (saver) 0-629

Suaafraa 0-1S2

Puplai (commnii) OSSS

Curk ..... 0-2iV

r

^H " The weight of water for the above ia btken at 1,000.

^B " Experience had sbowii that the time wheu treea are felled

^PvM much influence upon the condition of the wood. A ttial

"'WM made in Germany with four pieces of uak, cut down in Do-

cember, January, February, and March. A tin ring was fixed at

one end of each of the four pieces: theao rings were filled each

with two quarts of water, and it proved tliat the piece of wood

cut in December did not permit any water to pass tkcough its

■' The January wood, after forty-eight boura, passed a few
^—dropsj during the same time the entire quantity had run through
^^tte February wood; and the water liad passed through the
^Bfarch wood in two hours and a hal£ This accounts for the
HIbct that barrels, of which the wood was felled in February or
Mardi, will luae within « year ba much as 8 quarts of water,
wliilst others lose hardly any at atL One should suppose that
wood would absorb Bait water mora easily than fresh water, be-
cause of the pressure of the former being so much higher; still,
this is Dot the case; and Mr. Duhamel has proved this by an
experiment. He took two pieces of oak from the same plank,
each weighing 6 pounds. During eleven months the one was
exposed to sea water, and increased only by 2*141 lb, in weight,
whilst the other put into fresh water increased by 4-141 lb. in
weight.

" Wood which lies in the atmosphere will constantly vaiy in
weight, which depends upon the wet or dry season, and as ^he
action is accordingly, we find the wihkI in its section, in a regn-
iai bygrometrical action.

" If we attempt to abstract all moisture by heat from the wood,
we must not forget that at the same tune we destroy ite nature; ;
that iE^ the physical condition of the wood, by which it becomes
very liable to break. Too much hot oil on wood has abnost the
same infiuence ; by this it loses considerably in weight ; and
soon after the oil has been put on, the wood becomes brittle, and
U-arps moro easily than in ita naWwA ^a\e.

WEIGHT or TIMBER. W

"Tlie reroaiiuier of ilie sap, which is left in the pows t>i [>li«
timber, serves aa a binding substance in the vholi>. It aUo pre-
vents hjgroBcopical action provided tht! tree was cut at the pro-
per tima The hygroscopiclty is in couatant action in tlie wood,
and affects its body, shape, and weight, which in time leaiis to
its dissolution.

" This change is an much a chemical as a physical process, luid
noticed in all woods. The weight of wood is of great impur-
because its hardness, resistance, aud its heating power,
well as other valuable properties, are all more or leas depend-
upon it. Let us, therefore, enter closer into tliis subjeot.
In the first instance, we must consider that oven wood which
has been forested very hght will become heavy when put fur
time into water ; but in such timbers the sap is already
to dissolution. If the fibre were the only substance in the
then the siieeific weight would de[>end upon the number
poiee contained in its body : the pores are, however, filled
Ltb a substance such as rosin, die, &a. It comes to this : that
ing trees contBin a great quantity of eop, whilst old treea have
proportion less ; a volume of air being contiiined in-

we leave the troubleaume portion (the water) out
t Uie question for a moment, and inquire into the reason which
a the heavier or hghter specific weight in dry wood.
"Thehardest and heaviest woods come fiTjm the hotter ohmates;
the only exception is the pine, which thrives considerably better
and furnishes lieavier timber when it has grown in colder regions
or upon high mountains.

" Trees grown on northern slopes furnish lighter timber than
if grown on southern or western. In these remarks we have "
already noticed the fact that the soil has great inflnence upon the
width of the yearly rings ; and I also remarked that from this
I able to come to a couclusiun in regard to the specific
pReight; We have since heard of a uuraber of facts hy which
' lU between the yearly rings and the specific weight
IB greatly modified ; but, aa an instance, I mention the fir and
^rch trees^ which both ai-e heaviest when their rings are smalleat.
"Another influence upon the specific weight is exercised by
p resia and the die which are contained iu the inteiioi: i^ the ■

_ CIS

M2 ENGINEERING FACTS. [Drv, VHl.

wood. On level dry grtmnd or deep sandy soil we find the fir
(Pinus 11/leestrvi) boiutifully red inside; iu the same condition
we fioit the leg-iir (Pimai muff/nig) on turf soil whej« there is an
abundance of water ; but when we look at it on liaa soil, it shows
broad yearly rings and hardly any colour at all The larch tree,
;i^ain, in such Eoil developes itself well, with a rich colour. The
cuu^ for these appearances must therefore rest with the chemical
iMjndition of the soil and ita effect npon the individuality of the
lir, Oake generally furnish good timber when grown slowly in
dry ground, whilst those from wet soil appear comparatiTely
spouji_v ; aimilar results are obtained with other trees.

■' Trees cut in summer give lighter wood than when felled
during winter time. The cause for this may probably be
SBcribed to the fact that in wiiiter a large amount of nouriahment
is stored in the stem which, during the spring and summer, ia
spent for the formation of bloom and leaves.

" We call hardness of the wood resistance which it opposes
when another body enters it. If wood were an equal body like
ininerale, we should ba able tn determinB ita rcBiating pnwer or
hardness; but it being differently built, and, whilst trying its
hardness, other properties interfering, we cannot arrive at a de.
cisive result.

Sometimes a wood has very hard fibres but very little body;
lat is, it is lighter built than another wood with soft fibres and
ra full body : it is therefore unadvisable to judge the hardness
wood according to its fibres. Experiments to ascertain its
hardness sliould be made across the stem and not upon a longi-
tudinal section; and although there is no instrument which leads
us at once to a definite result, we can generally arrive with a satr
it a fair conclusion. Many persons constantly employed on wood
bre of the opinion that it bec<imes harder if it is workcil or barked
Whilst green.

" Wood, as a porous body, contains in its natural state —
whether dead or alive— a certain amount of moisture: hy the
loss of that moisture or increose of the same the bulk of the wood
either contracts or expands.

" If we have a piece of wood when this action takes plac«
opon one side, it is obvious that the piece will alter its fonn
«bape.

V

K.} ELASTICITY OF TIMBElt,

" Tlie cansequeDce of the lose of moislui« is &\m the warping
and aphtting at the wood. The inner structure of s stem ia irre-
gular: for iDstaiice, we find the inner moisture of a yearly ring
to he more than on its outer side: thia causes the splits on t'l.-
exterior, after the wood is dry ; and it also accounts for tlie
impOBsibility to form out of green wood a regular body which
could not lose its weight or fihape. The time during which the
evaporation of the moisture takes place depends upon the statp
of the atmosphere. Several authors are of opinion that the con-
traction ia regulated by the specific weight This, as a rule,
cannot he adopted ; for instance, lilac and oak both being heavy
and hard, contract quickly, whilst the double American maple,
which is equally hard, contracts slowly. It is evident, however,
that the fiiUer of sap a tree is the greater will be tlie contraction.
This will account for the fact, that we find on cut timber the
cracks extend frtim the exterior towards the centre, because the
snpwood will contract more than the heart-wood.

" Planks turn with their sides upwards; that is, the edges rise

from the level of the centre line. This explains why we turn

the inside of a plank towards the joists whilst we lay a floor,

which prevents the twisting. The contraction and action of the

food cannot be checked altogether. Among the means to pre-

it stands foremost the one of putting the tree into water;

when taken unt it must not be stored in a place where it

too soon, as it still would burst if lione ; nor must it be left

long in the water, as this will injure the quality of the wood.

All the wood which is used is never quite dry: besides

it works a little in itself under the changes of the

lospbere; and therefore attention mu.st be paid to the aelee-

the timber for the same purpose, for the heart-

il ia less subject to such action than sap or splint wood, This

important point with the furniture niakera. The expansion

contraction is less apparent in the length of the fibre than

the cross section of the wood.

" The elasticity of the wood ia called its property of return
original form and shape after such have been altered by
er cause. With this quality is connected the valuable fit-
>f some woods to transmit sounds, for which reason they are
used bf insCrament makers. The elasticity has its limit;

ENGINEERINO FACTS.

[Div. VllL

I

Itnil the more a piece of wood oan be bent without breaking tb«
greater its ehuticttj.

'■ The resistance of wood de].ienJs upon the three following
eonditioDa: — 1st. Two pieces of equal length aai height offer
different reaistanee with reference to tiieir breadth. 2d. Two
)}ieces of equal length aud breadth offer different resiatonce with
regard to their height. 3d. Two pieijes of wood of ec^ual heiglit
iiud breadth offer different resistance with regard to their length.

" Again, experience has proved that a piece of wood resting
freul; with its two eiida will carry from one-third to ooe-batf
lusa weight than if the ends are Jixad or built in a wall Old
wood has less elasticity than young, and heart-wood ia less elastic
than sap-wood. The same difference is found with wood &)iii
the lower etem compared with that from the upper crown. Tim
elasticity dimisiahea with the progress of the specific dry weight.
Sqiiarp-cut timbera laid horiEontally with their yearly rings have
not by far such bearing power as when laid perpendicularly.

" Green wood has considerable elasticity. Toung stems,
although they suffer sumetiiaes by the wind, will region their
original poeition in a shoi't time. Here it is necessary to men- I
tion that where young stems or branches have been bent through I
snow for a longer period, they will not return to their former form. [

" I submit to you the following as the resiilt of some experi-
ments relative to the bearing capacity of various woods. Thn
pieces were all three feet long and 2 inches by 1 inch, and air- I
dry. The constimta arrived at were the following: —

°. i^'esu

29 002 ,
33-437 ,
■STt; 41-812 ,

37-312 ,
45-760 ,
45-312 ,

SB '750
G3'312

Yellow Pine

35S

BaiCic PiDs

Red PlDB

4(17

Ash

517

English Elm

595

Pitch Pine

e20

Aincriflan Elm

831

American Oak

flaD

Africaa Tonk

878

Mora

Bfi]

Sabicu

854

Afi-icau Ouk

889

Gi-aenlieart

1,079

English Ouk
laSau Teak

—

^HlBnn.] BKEAiiING WEIGHT OF TIMBKR. S85

^H IroQ Wood — ... 7S'50n ,,

^H English Larch — ... 32'GfJ2 „

^^V " Ftirmula to find the breahing-weight of a piece of timber : —
^^Bbuastant, b breadth in inches, d depth in inohes, { length iti
^^nt, w breaking-weight in pounds.
^B

" The adaptability of greenheart fui' hjilrLiulie oonatriiction,
dock-gates, &C., cannot be over-estimated. I refer you to an instance
where a olough was taken out of a spwer after si.xtflen years; it
had been made half of oak and the other half of greenheart:
the oak was completely worm-eaten, whilst the groeDheart was
in its original condition. This certainly contrasts with the fact
mentioned by Mr. Buraell in his paper, that he has a piece of
greenheart riddled by the teredo; and it would be interesting to
ascertain undcp what circumatances the teredo will attack or not
attack this kuid of wood. My experience proves that greenheart
~l|«empt from the theroaion by the teredo ; hut there is a mol-
C in this timber which we find ahve in it lu< the same arrives
e from the West Indies. The worm is found in sizes from
) lymexylon to the teredo ; but is of a diffi^rent species, and
B not to live in this wood when usedin sueh constructions as
Sok-gatea, &c., in this country. Green sapwood will not retain
B form and bend if it ie easpended horieontally by its two ends,
me will occur in timber constructions where green
aod has been used I may mention that the artificial process of
^ing wood should not be extended beyond 10 per cent., because
It will cause it to become brittle and totally oseless. A close exa-
mination of a beam supported by its two ends will teli that the
upper half of the fibres are stowing while the lower fibres are
extending. The centre of gravity lies in the middle of the cross
section. AH woods do not offer the same resistance, and we can
increase it by strengthening the centre of gravity. M. Duhamel
describes in his work, ' De la Force des Bois,' the following ex-
riment in elucidation of this fact : he took twenty-four sticks
nt fiflm young willows of equal strength : each stick was 3 feet
■is) long, and 1-J inch square. Six of these broke in the
y iri(h an itrer^ weight o£ 256'909 kUo^auimea (I kilo-

ENGINEERING FACTS, [Div. Vlll.

[ giamtuu equnU 2'205 lb. Englidb). lu two other pieces h
I a cut across ^ inch de«p in the oeutre, aud tilled it out with u
I piece of oak : they broke with au average weight of 269718 kilo-
f grammes. Two more were cut ^ iniih deep, and otherwise treattnl
le manner; they broke with 265 312 kilt^rammes
t Five were cut J inch, and broke with 259'7G4 kilogrant

From this it results that the smaller piece of harder wood, fixed
I across the centre, considerably increased the strength of the sterna
when put in half and even three-quarters of the thicknees. It
is also the rea;wn why a beam composed of several smaUei pieces
will bear as muclt as if of one eutite piece. And again, as tha
bearing power of the timber voriea, some advantageouii resulta
may be olitaiued by putting etrou^'er and weaker wood together
in a construction.

"A round or square piece of a stem will nffur about the ai
resistance from each side ; but if we compaie a timber out witb
the yearly rings VL-rtically with another having the rings hori-
xuntaliy, we find that the former will bear mure than the lattar.
"The sap which protects the wood does not prevent its deca^.
Turpentine, which is often in the sap, prolongs the preaerratioii
of the fibre. According to Baron Liebig, the decay of wood
takes place in the three following modes : first, oxygen in Um
atmosphere combines with the hydrc^ni of the fibre, and 1"
oxygen unites with the portion of carbon of the fibre, and bi
porates as carbonic acid. This process is called decompositioaii
Secondly, we liave to notice the actual decay of wootl which takes
place when it is brought in coutact with rotting substanoeB ; a
the third precess is called putrefaction. This is stat'^ by Liefaig
to arise from the inner decomposition of the wood in itself ; a
loses its carbon, I'orras carbonic acid gas, aud the fihre, under Uw-
influence of the latter, is changed into white dust.

" As an example of this, 1 refer you to the woodeu eeilinga

of houses wliioh after some time go into that state. The chief

cause is, that the free access of the air to the wood is preveuleii,

aud the iittle dampness occasioned by washing is aulficieut to pro-

L mote the dry rot.

"The sap of wood contains partly sacchariue matter, which
hKi'JJ iiatarally decompuae iti \.t»iVf, 3.ad this is noticed in ttmUt
ts ironi the aouv laate b.i\4 amis'i o^ wida "sui^Aa.

LiUBEK.] PERIOD FOE FELLING TKEES afl?

" Tim actual time whicb wo<)<l liuU depends in a great meoiiure
on the time wlion it was felled, and in how far the soil in whifli
it grew was suitable for ita develupment.

■' As a rale, the wood cut in summer is lesB durable than tlnit
felled during the winter months.

" It will also be the cose with trees which remain a longer
]>erioJ before their removal in tlie forest after being cut ; Iinw^
ever, a great difference does not ejrist between ripe wooda, whether
tJiey are felled in the summer or winter time, because the formn-
tiiin of the leaves and the hlosaoma affects only the sap woi«i
mid the bark of the tree ; therefore, if the sap wood ia cut off
.lud the heartwood is properly treated and seasoned, the quality
lit' the summer wood would be equal to that cut in winter time.
Ill support of this I mention, that most of the trees in Southern
It.dy are felled in July and August.

■' The pines in the German forests are cut down mo.^tly iu sum-
mer time, and their wood is generally very sound. The notion
that this causes dry-rot must remain out of the question, for I
believe whenever such takes place it is in oons>«juence of unsen-
soned timber being used Considering the lai^ quantity of
timber imported into this country, I must mention that my ex-
perience tends to show that the North American woods, with the
exception of red pine, are leas durable than those from the uoHh
of Europe. Tlie ktter are stronger, superior, and not m much
subjected to dry-rot as the former.

" In the earlier portion of this pai»er I had oceasiun to men-
tion some enemies of the wood which attack it wiiilat growing;
it ia lucky that they are combated and destroyed to a. great ex-
tent by other animals in the forest ; and, among those doing
great service in this respect let us remember the woodpeckers,
linches, swine, hedgehoga, badgers, frogs, and many others.

" Dry or dead wood has also some terrible foes, which at times
cause alarming ravages ; and unfortunately no effectual means
have as yet been found to check them : the moat dangerous of
tliem are the termites, the Ijmexylon, the sirex gigns, the tereiio,
and the lymnoria terebrans.

" It is sometimes difficult to distinguish good from bad timber,
and I beg to draw your notice to some illustrations from a work
publi^ed bj the Sieack GDveniment, — ' Inetiuctiona am les Bois

I

I

|S8 ENGINliERlSG FAfTS. [Dtr. 71IL

do ilarine,' with special reference to the oaks, anil to which th«
following explanation may seive : —

"Plate 43, figure I,* represents meagre or better known ae
English oak, of the best quality. To this kind of oak belong
the Qiie)v«j pedaticulafa, and the Qaereua sessUiJIora. The &e£h
cat of euch ia a yelluw straw colour, sometimes of a. rose colaur.
The annual rings show a fine glossy grain, which allows it to
take a fine polish. The homy layer of three to five railliniBtrM
IM quite di>4tiuDt from the cellular portion, and the poree are verj
little to be seen.
. This kind of oak is very sensible to the influence of the atmo-
iphere. In damp weather it swells, and in a dry temperatnro it
contracts considerably. This makes it liable to split ; but not-
withstanding this it is excellent wood, and the best suited for
^the ribs in a sbip. The fibres hold together with a great longi-
tudinal and even transversal tenacity, which gives it a great re-
pstiag power.
" Plate 43, fignre 3, (see foot note), shows the cross section of
an iofeiior quality. It i; spougy; lia^ lai^e pores of a pale
colour, aometiniea broivn or reddish ; its deficiency has been
caused by too wet a soil, by want of nourislmient, or of &esh

»ot of any other condition requisite for its full development
" If such wood be ruptured it mil break clean off, and a fibre
may be rubbed into dast between two fingers. A valuable pro-
perty of this kind of oak is, that it altera very little by the
changes in the atmosphere, and it is therefore much in use f
floors, furniture, and carpentry.

"Between, these two qualities of oak, range a great number
others, differing in their condition.

" When trees are found to be vicious at the trunk, it must
[■attributed to an interruption of the functions of the roots. It
i-will occur that one or several of the roots die, by which putre-
ffection is imparted into tbe lower part of the stem. If this rot
\hB white or black, it is not very dangerous : it does not generally
each more than 1 foot above the roots ; but when this rot i^
if red colour, the wood should not be used in constructioi
soon lead to decay.

Trees arrive at an age when their wood beoonias
JTot given here. BeeSo. oS 'Buildw' ^m^Sia.Wia,-

TisiBEB.] DISEASES OF TREES. 360

then it is time to fell them. It may be seen vhva the top of
l)ie true brings forth no leaves v Bprii>g. Such treus arc super-
Hnuuated; that is to say, Uiey grow no longer; onii tlieu they
become Bubjected to a serious evil called the dial. This is ex-
plained by the following process : — We know that with a vigor-
ous tree in full growth the heartwood contains the smallest por-
titin of wat«r, and that its density decreases from the centre to-
ivimls the cii'tiumference : when it is felled and dried it will split
from the outer side towards the centre. This is nijt the ca^e
«-ith a superannuated tree, in which the oldest wood begins to
perieli first ; and consequently the greatest density lits between
the heartwood and tiie bark Sotr, in sucli a tree the central
wood contracts while drying, which causes the splits. Some-
times splits are found in trees whicli bear a glossy blackish
aspect, and they must be distinguished from those just men-
tioned. Tljey extend from the circumference towards the heart,
and were created whilst the tree was growing. It is asserted
that they are effected by frost. They Iiwk at first straiglit or
capillary, and enlarge with each heavy cold. They show Ihem
selves mostly longitudinally, on a swelling of the stem, and make
the tree useless.

" The splits in the heart of a tree must not he confounded
with holes caused in falling. There is no danger with the latter
beyond that they dimiiush the length of the timber.

" Otten in the trunk of a stem a particular irregularity is
found in the non- juxtaposition of two successive annual rings.

" This fault is cansed by strong winds, which affect it in the
point where the flexion of the stem has its maximum.

" It will also arise when the tree has not suflicient nourish-
ment, by which two layers are prevented from growing well to-
gether. It shows itself in incomplete dark rings. If these are
only in the sapwood they may be looked upon as unimportant;
but when they are, on the contrary, in the heartwood, and ac-
companied with the dial, they betray a serious vice in the tree.

" In difierent ci'oes sections of an oak we often notice cii'cular
bands of a different colour from the remainder of the section,
sometimes white, yellow, red, or brown. The texture of these
bands appears loose, even spongy, and betrays signs of decom-
position. It is found in the best qualities of wood, and it can-

ENGIBEEniNQ FACTS. [Div. VII

^^f not be cured. Tlis reason for this decay is not definitely Icuoi

^V gome persons suppiwB it to arlsa when the aopwoud ib prevented

^1 by severe cold from developing itaelf into good wood. When

^P this evil 19 in the heart, it looks like a whitish circle, and is

called the moon. Wood from such trees ought not to be

because it will soon decay. When the vicious bands are straight,

and the shades of colour are less observed, the

" l>ruxy knots are cauaed bj woodptckere, by lopping, and by
de»J and broken brauchea, which muke holes into the tree : into
these the water nins, decomposes, and directs the evil towards
the inner stem. If we find on a tree a swelling or depreaaion,:
we may conclude that the condition of the tree is bad.
trees are often found with the sap running out of their anupit&:
Among the varioua rots engendered by the knots we Lave the
^L following :-

^H " Wet rota are coiupuseit of porous fibre runuing Crum tltS'
^H knot into the trunk of a tree. This rot is of brown colour, and'
^V haii an offensive smell.
^M " This evil is often fouud with wlute spots, the latter of watery

^B substance. When it has yellow llames it is very daiigi
^M Black coloured knots are easily cuied, and unimportant
^M " We find wounds on trees which have been efiijcted by the

^H fall of a neighbouring tree or by the friction of a cartwheel
^H through which the riud was torn. If this wound does not reach
^H beyond the bark, it ba^ no bad eifectupon the wood; but should
^B it have damaged the ligneous portion of the stem, the wood
^M takes soon a greeu-like colour, and begins to decomposa
^H " It occurs that a new rind grows over such wiiunda, and

^H such instances the evil is not detected until tiie stem is cut into
^H timber. Similar defects are also caused by lightning.
^H " As a very elaborate work upon the various kinds of oak, I
^^L mention Kotscliy's, Eichen Europa's, Durability awl Preservation
^H of Wood.

^^H " Well-seasoned timber will last for an indcfiuibe period if
^^P .kept in dry air or under water; hut when alternately exposed
^H^ to atmosphere, water, and hght, it begins to decompose. The
^H ordinary causes bj which this is effected are chiefly the fermen-
^^^tatioa of the azotic substances wyiWwqA \n \k4 kaM-^W

TiMBEK.) PRESERVATION OF TIMBKB. 3(1

Tliia is developed under the influence of the oxygeii in the atmo-
sphere, aud bj tlie moisture contained in the wood. \Ve have
therefore the problem to find means to prevent this fenueutation,
either by obviating aU such ctrcumstimces as air aod water, or
to extract from the wood its vegetal albumen, or to act upon the
latter in a manner that it resists fermentatiDti, and abio the attack
of ineect£. So process has as yet been invented which answers
to all these conditions, and with all trials we must have Ibe
assistance of chemistry and entomology,

" I refer to our museums as the place where, among other
rude-made articles, here and there is left a remnant of wood
nhicb bears the ages of decenniums, and other specimens of
pctriJied wood nhicb must have been in existence in its natural
state centuries ngo.

" That wood in sandy soil will lost for centuries may be seen
in the specimens which were dug up whilst making the new
docks at Birfeenhead, from depths varying from 8 feet to 32 feet
below the surface, and they ai'e reckoned to have been there for
centuries.

"Among the many inventions to preserve wood, those oi' Eng-
land have proved the most successful. Already in 1737 a
patent was granted to Mr, Emerson, to prepare timber with
hot oil, and soon after the methods of Oxford and Kyan came
into nae.

In 1837 a patent was taken out by Margary, to impregnate

twith sulphate of copper; and since 1838, Sir William
lett'a system, chloride of zinc, was also used.
Mr. Payne obtained a patent in 1841 for preparing wjod
h two solutions, such as carbonate of soda and sulphate of
iron. Some very good results are obtained with this system, bnt
it must be done with the greatest care.

" Still better is the invention patented by Mr. J. Bethel),
which consists in the injection of oil of tar after tbe nir has been
extracted. This process is effective to a groat extent, and for a
full description I refer you to Mr. Brunell's paper, read liefore
the Society of Arts, in Loudon, 1860.

"The disadvantage with the creosoting syBtem is the offensive
and the increased danger by fire ; but it is recommendable
jailwsys and hydraulic works.

^MOQd
■Mth

ENGIIfEEEINQ FACTS.

[DIV. VIU.

" In France the price of creosote is too high to a>.limt itt
Wneral uae; and eolutions of metallic aalts are used insteflJ.
Ainotjg these M. Boucberie'a method haa obtained the Iwst n
Isult^. Ue acts with a pressure of 5 or 7 feet of water upon

>o'l not later than two ur three months after it is felled, and
njectB a solution of sulphate of copper by a transversal Eection,
while the eap runs out in the opposite direction. Bailway
' eleepurs prepared in this manner were laid down in 184S ; and
in 1853 they were in such good condition that evur since SJ
Bouoherie'a system is much applied in France. Another eeom
niical process of Mr. Foutenay is worth mentioning. He acts
upon wood with what he calls metallic soap, which he ohtaim
from the residues in greasing-boxes of carriages ; also &ora the
Acid reniaina of oil, suet, iron and brass dust, which axe a
melted together.

■' A piece of wood was put in such a hot fluid for forty-eighl
hours after the water had pre^-iouslj been partly extracted under
the ordinary pressare of the atmosphere. Wlien taken oat the
metallic solution which it had taken up stood at 3 per cent, In
Sta first weight This piece of wood was used as a railway
sleeper on the Orleans Railroad, and after eight months it yi
in i>erfect condition, whilst other wood not treated in simjiir
manner was in a state of decomposition.

r process is the following, recommended by Mr. Don-
much applied in France and Germany, tt is a ptiat,
consisting of the following ; —

!5 kilof

igramraes.

_ l.itJiarei

^Btfl/ these a

Zinc or white lead
Vermillion, red or yeU.
Colour (clay oaluurs
thicken too mu(
CeniBnt
OiidB nf iron
Gatta perulm, elue, i
Hydrate of chalk
Lanl .
I.itliargB

(Ode tUopfliumB = 3 -SOB lb. English).

TiMiiKB,] PKESEUVING OF TlMBKl;. 3;-t

WTien applied warm it nuiy be useil with a biiish ; but not tiio
hot. IJ may alsu be us«d cold ; in wUioh case the paste miiBt
lie miseii with a little varnish or turpentine oil. Tlie re.iiiH*i
I'btained with tbia pn'ceas are reported aa yet very aatisfiictijry.
It prevents decay, and admits no hnniidity.

" Mr. Dondeine further reports that it prevents nxydation of
iron ; and wherever walls have had a coat of this mixture it ha^
kept away all wet, and unpleasant insects, anta, bugs, Ac. Rjolls
of pasteboard or of wood which have been painted with the mix-
ture keep dry, and withstand the effects of rain and snnw.

" Wood impreguftteii with sulphate of copjier will not last
longer in sea-water than other wood. It is quite as niueh a^
tacked by the sea worm na when in its natural state. On the
other hand it has been proved that wood imjiregiiuted with sul-
phate of copper, will have ion^r durability in the soil thiin
when either tarred or charred.

" The fallowing statement of M, Broiizet to the Freiidi Aca-
demy may also he of interest. He has a seat in the Careimes
Mountain, where he cultivates aUk-worma The Bhelvee upon
which they breed are of pine. During the period from 1853 to
1868 all liis crops perished througli illness. In 18C0 he was
' o make new shelves of pine impregnated with sulphate
jt-fiopper, and ever since the ailk worms have been in the finest

1 healthiest condition. (See ' Cumptes rendus de rAcadomie

LDjiaise,' vol. 54).
L " At Saint Sebastian, in S]>ain, the piles of a wooden bridge
" .ve been guarded against the attacks of

TVonnB in the following manner. Each pile is surrouuded by
■irooden box, and the space between tilled up with cement.
K years it was proved that the pilea were in perfect ci>n-
fetion, whilst the outer boxes were completely riddled by thu
pomis.

" With these I conclude the remarks on wodi], and will nest
nisidersoneworkswhich have been constiueted in that material''

On the Growth of trees the following is a note addressed to
' e Editor of the 'Engineer^ by William Bums, C.E, : —

" The following article on the growth of trees has appeared in
several periodicals lately, hut while the article shows the piipulur
^TOF it does not explain the cjvuse ot thft vfnut of uy.i&KivLt"j in.

ENGIKEERING FACTS.

[Dn-. VIII

^^F the thickness of the annular rings of trees. Will you allot
^V tlierefore, to append a few facts which might be of some .value M
^1 a number of your readers : —

^^ " ' Popular Erhob Kegardisg the Want of Uniformity in

^B THE THiCKNEsa OP THE ANNULAR E1NO8 OP Trbeb, — On reference

^H to the cross section of a newly felled tree, it will be obaerveil

^F that the timber has not formed of uniform thickness round the

pith of the tree, This is uniformly the case towards the base

of the spniee, Scotch fir, and larch. The popular belief is, that

the wood forms faster towards the side most exposed to the light

I and the heat of the sim's rays. Were this the case it would
prove that we have more of these from the south-east than from
any other quarter. The prevaUing high winds in Britain are from
the north-west or south-west, and they usually blow hardest i
autumn, when the young wood is moat liable to be permanently
bent in any given direction. This makes the top lean towards
the north-east or south-east; and, by one of the many admirabla
compensating operations of the Great Creator, the wood at the
base grows fa&test on thofie sides. So that it may act as a natural
buttress, and maintain the centre of gravity.' ''

" The above is a very old-fashioned, but very unaatisfactoiy,
method of trying to explain the cause of any effect we do not
understand ; in fact, it is no explanation whatever. We know
that the Great Creator is the first cause of every operation ia
nature, hut he at the same time causes secondary laws to govern
many of the operations of nature ; and if we exaniine the powers
operating upon the growth of trees, we will Und that it is by
simple mechanical action that the annular rings are always th~
on the side opposite to the direction of the prevailing i
because, when the tree is bent, it forma a bow or arch, and tho
fibres on the convex side of the arch undergo a tensile stiain,
which partially closes the pores of the wood on thai side; whU^
on the concave side of the tree, the fibres undei^o vertical c
pression, which has a tendency to open the pi.ires on tliat side;
consequently the sap rises more freely on the concave side, iinii>
more rapid growth on that side than on the other; af
a lime the wood is much tiofter than on tlie convex side.
In proof of til 13, toket\ieSco\*.\ife,'Wp!fi,Q^s^Ta'^,».i\d.exainitia
a section near t\ie Vhwb ■wi^V&j"'"

PRESERVING OF TIMBER. 375 ■

md that the pores on the convex siiie are raueh finer and com-
ut th^n on the other.

" Again, take a longitudinal section of the tree cut through
' e centtK eo aa to ahow both the convex and concave sides, and
it will be found that on the convex aidea the fihrea ore hard and
run in nearly striiight liavs, whereas on the concave aide they
are soft and have a wavj appearance caused by vertical com-
pression. Again, cut equal portions from the convex and con-
cave sides of the same ti'ee opposite one another, and dry them
tborougiily, aud it will be found tliat the wood from the couvex
side lias a much higher specific gravity than that from the concave
aide. Again, the wood cut from the convc-jt aide is much stronger
and will sustain a gi-eater tranaverae strain than wood cat from
the concave side of the same tree. Again, the wood cut froni
. side of the tree is more durable than that from the
le. Where Scotch tir, larch, or spruce haa heim used
? poofiiift joiating, or flooring, I have always tound that the
3 side, with the larger fibre, gata worm-eaten and quite
Bthm lung before the other side. These facts I discovered many
s ago ; a knowledge of which is invaluable to parties using
t kind of timber to enable them to know in what direction to
rat up the trees for certain purposes."

On the Premroaiion of timber from decay the following facta
from the 'Builder' will be found useful: —

" JFrom reliable experiments that have been aiade in Europe
i the East Indies with railway sleepers which had been treat&l
with pyroligneous acid, it has been demonstrated {says an Ameri-
Q paper) that they endure three times longer than the aanie
i of timber, not so prepared, when exposed to similar influ-
Kices. Many improvements that have originated iu America
We been iirst applied in other countries. This has been the
8 with respi'ct to the treatment of timber with pyroligneous
atiid. Its apphcation for such purposes was proposed in New York
forty years ago, but it haa not yet come into general use there,
while it is iu very common use in England. In the Mew York
J Daily Advertiser^ of Dec, 24, 1823, a description was given
i experiments that had been made in treating timber with pyro-
I acid, and its benefits and modes of application were
F deombad. So railroads ^ere \kea m e^tAKOiK^ «(«»««i- j

F

~ quel

KNGlNEEltlNG FACTS. [Drv, VIII.

queiitly, its use vaa chiefly urged for sliip tiuibei exposed to lupid
decay. The article on the subject said r — ' When seasoned
timber or plauks am hewn into the intended shape, put them

II under cover for a week or ten days to protect them from tha
^^^ Bui-iug tliis time let the acid be applied to the aiirface daily wiUi
^^V ft bnuh. It will penetrate an inch or more into the wood, and will
^^I'.bt: found an clTuutuai pn'scrvativc The central part nf the wood
^^K or heart of the oak lieirig less liable to decomposition, it will
^^M quire less of the Kcid, The frame of the ship or boat may be
^^B put together when all the external parts of che timber are i
J^f jiletely satnrateil. Uwen timber cut in tbick forests after being

III satuvated with lliia acid will be nearly as good for ships, steam
and canal boats, as the teak wood of the East Indies or tlte live
oak of our sea-coasts.'

^_ " The pyroligneous acid recommended for this purpose wai
^^L condensed smoke of wood. The best way to obtain it is by tlis
^^m tUstillutioD of wood in an iron retort and the condensation of
^^f its vapour in a refrigerator. The charcoal thus obtained

retort ia of excellunt quality for amelting iroir, and the crutla
pyrohgneous acid may be applied without any further treatment

I to the timber. It was not only reeommcnded for ships' bniber
to prevent dry-rot, but also for the timber of gun cairiogea, poets
set in the g^)Ulld, the ^ills of wooden buildings, &c. By
smoking timber in the same manner that hams are smoked,
eimiiar results are obtained, for the preservative agent ia thi
creosote in the fluid and the smoke. In coal tar there is a simi
lar preservative agent called carbolic acid, which in many of its
ptopertius resembles creosote. It answers the same purposes aa
»n antiseptic for timber, and is used for this object, but it ia dis-
agreeable to apply ; wherever it can be obtained oonvenientiy,
liowever, no better substance can be applied to timber intendad
to be exposed to moisture and the weather, more especially when
in contact with the ground."
From the ' Bulkier ' we also take the following on the use of
petroleum for prenejiihig wood: —
" The oil wells near Prome, in Burmah, have been in use from
time immemorial. Wood, both for ship-building and house'
building, is invariably BAtui-.iWL oi to^WS. vi\tt\. Uuj product ol
I tJioae veils. Xiie leaalte isi M\\is« immvi.'aA'j 'iio'ai. i«f3>.^,«.-oi.'i!B

PHESER7ING OF TIMBER. 87'

'tkgee of the whiW ants wbich in that country are so generally
itructive. M. Crepin, a Belgian GoverDiuent engineer, whu
tried esperimenta on tlie relative aJvantagea of creosote and
Iphate of copper for tlie preserratiou of timber in marine ci>ii-
itions from the attacks of wormB, &c, says tliat creoaoting
l^e only process he has found to succeed for thie purpose.
Btatea that aulphate of copper affords no protection whatever
it the action of salt water atiil maiine insects. The Belgiuik
ivemment now require that all the wood sleejiers used in the
its railways should be creosuted ; and the Government of Hoi-
id have also made the same resolution ; and upwards of
10,000 fiieepera per annum are now being creosoted by the
itoh Government, and more by the Belgian Government."
A correspondent, " A. T." (Antwerp), writes to the ' Builder'
Wood' Praseiixitive Prncesate alitiatl : —
1 have read with mucii interest the artitle in your journal
iUed ' Notes on the Properties of Wood.' Noticing the im-
ice you attach to the different processes for preserving
wood, I moke bo bold as to cSwr you some data wbicli have been
arrived at iu Belgium, Holland, and I'rance, concerning their
relative merits. It is quite true, as you say, that the continental
engineers esteem the processes of English origin the moat highly,
and especially Mr, Betliell'a creosoting process. The efficacy of
the creosoting process has for some years been admitted in the
most absolute manner by the engineers in the Ifetherlands, and
no other wood-preserving process is used by them. It has been
proved in an equally aliaolute nmnner in Belgium by a series of
experiments upon the principal wood-preserving processes, made
the Belgian Government engineers. These experiments have
ted through a period of twelve yeara, and were conducted with
greatest care and vigilance. Iu the course of these expori-
Uenta there were laid down creosoted sleepers, 223,664 ; sleepers
prepared with sulphate of copper, 199,061 ; sleepers prepared by
other processes, 25,730. And in 1860, 'C<)iupte Kendu dea
0[i6rationa des Chemins de Fer Beiges, I860,' page 28, the
Minister of Public Works published hia determination to pre-
pare in future all railway sleepers with creosote, except the oak
sleepers, which are not to be prepared at alL M. Crepin, a Eel-
it eu^neer, vrko \ia& Wua^ «:i.^Yvuufe^'a.\Ki&tJi;i» i

I

ENGINEEttlNO FACTS. pir

relative advantages of creoaute aai] Bulphate of copper for tlia
preservation of timbei in mariae constructious from the attacks
of worms, &c,, has lately published a report, 'Annalea dea Tm-
Pubhcs de Selgique,' tome 19, in which he states that
creoaoting ia the only process he has found to succeed for this
piirpnse. Indeed, lie states that sulphate of copper affords
protection whatever against the action of salt water sjid marina
insects.

"As reganls France, I must add that although immense quan-
tities of timber prepared with sulphate of copper liave been used
by the French railways ; nevertheless, there also, experience
points to the condemnation of this preservative. At the end of
the last year, the committee of the Belgian engineers
able to reconcile the facts they bad observed in Belgium with
the opinions of the French railway engineers, and fearing lest
the failure of sulphate of copper in their experiments had been
occasioned by some imperfection in their mode of employing it^
the Belgian Minister of Public Works asked permission fit)m the
Nord and other railways of France for a committee of Belgian
Government engineers to inspect the sleepers prepared with aul-
l>hale of copper and placed on the said railways in France. "'
Msult of the inspection made by the committee proved to them
tiiat no better results had been obtained in France than they had
obtained in Belgium ; and tjiat consequently they had not to
blame themselves for any want of skill in their application of
the sulphate of copper process. It was quite by chance, through
my being iu Loudon for a few days, that I came to read your
article ; and it is in the interest of truth alone that I send
the above facts, which I hope you will kindly place iii your next

" The Belgian Government now require that all the wood sleep-
ers osed in the state railways should be creosoted ; and the Go-
vernment of Holland have also mode the same resolution
upwards of 300,000 sleepets per annum aw now being creosoled
for the Dutch Government, and more by the Belgian Govemmeni
" A, T., Antwerp. "
M. Lapparent, director of one of the French dockyards and
lapector of timber, in ptes&nXwig, a. te^iirt, Ui tW GoTeijuttent on
'ation of timbei, Btatea, omon'^ ti^tet 'Cm.-a'jj.,^ "' " "

a.]

SEASONINR OF TIMBER.

s^ of timber is composed of nitmgeiioua elements wbich are

called uiistaM(^ because under oertain vircumstances they are eo

liable to change — producing rot When timber is treated so as

to alter the nature of the sap or to dry it com|)letely by what is

called teaeonimj, it reaiats decay more effectually than if used

without being dried. Moisture and cuniined air tend to produce

decay la timber, and on the otber hand timber exposed to a free

ircalation of air and shielded from moisture will retain its strength

LOst animpaircd for centnries. The oak beams, rafters and

timbers of old churches and houses which were built before

plosteringof walls was introduced, have remained sound for six

' aeven hundred years. Of course, ships cannot be kept dry,

if their timbers are well seasoned before they are exposed to

elements, it has been found by experience at the French

'al dockyards that they will endure five times longer than

ibers not thoroughly seasoned.

well known that when timber is steeped for a certain
water, then exposed to the air to dry, it seasons more
idfy. It has been customary, therefore, to immerse ship timbav
water prior to drying it. On this head M. Ijipparent states
the practice of those shipbuilders who steep their timbers in
water is wrong, and that fresh water is the most suitable for
purpose, For oak planking, he states, it should be steeped
year in river water, two years in fresh water not ho frequently
iged ; while in bracldah water, continually changing, it re-
years' immersion.
" In drying timber to season it, exposure to the air is the most
lie method, but this requires a very long period of time fur
ship- timber. Another method consists in drying it in large
exposed to currents of hot air driven in by fans. By thit
I the surface of the timber is liable to becomu dry and
_ ik before the interior is seasoned, and for planking it is, them-
fiire, objectionable. Another method has lately been tried neat
Clierburgh, France, which consists in exposing it to the smoke,
Hteam and gas of wood and coal under cumbuslion. The small
lunt of moisture in the smoke prevents the tiukber from crack-
and Ml Lapparent looks upon this mode with favour. But
fovourite mi-thod in treating timber to prevent its decay is
iif its surface. He Btates tWt lima -^vam-^aaooBs*

ENGINEERING FACTS.

[Dlv. Vllt

I

"trio'l iliiruig the last century in the IJriti^li royal dockyards ;
tlmt the frigate Sot/al William was built of carbonized timber,
•Dii that it waa i)iie of the most remarkable coaea of durability
record. Thia ajBtem has bacii revived in France with iw-
■ppived apparatua, and it is about to he extended to all the dook-
yanla in the empire. The timber to he operated upon is secured
apou aa. ailjiiatAble taible and ita surface is slightly charred by ii
dame of gas mingled with a jet of air. The conaumption of ga-s
gallons fiir 10 square feet of carbotmed surface, and oue
u carbonize 440 square feet iu ten hours. Some timber
ia im])roved by giving its aurfece s very thin coat of tar before
charred. It ia stated that the whole surface of timber ia
carbciuized with great unifurmity hy this method, and M, La{i-
pareiit saya : — ' It ought to be applied to every surface in con-
taut with, or in general intended to bo surrounded by, moist und
stAgnant air.' It is also recommended for Creating tlie beauia
and joints of hou^e timber, iutended to be eiu bedded in the walla
or surrounded with plaster. By carbonization a practical and
ecouomical means is also uffi^red to mUwa; conipaniea of preserv*
ig, almost for ever, their sleepers, particularly tliose of oak. In
Francis, the annual cost for vine props amounts to no less than
24,000,000 dols. By charmig these this cost will be rednas.!
two-thirds, and a relative saving will also be efi'ected in thus
treating hop pok-s. As the vine and the hup are oxtansively
'Cultivated iu America, tlus system uUo deserves the attention of
our people who raise these agricultural products,

" III building ahipa M. Lappareiit suggeata tliat horizontal holes
'■hould be bored thrnugh the riha, at certain distances apart, and
'tiiere should be spaces between the outer and inner planlcing to
permit currents of air to be driven between the ribs, also that
portions uf the riljs should be smeared with a paint composed of
flowers of sulphm', 200 parta ; liuseed oil, 135 parts ; and man-
ganese, 30 parts, to prevent tlie development of fungu In citn-
cluainn M. Lappareut says : — ' I have pointed out the means for
preventing the rapid decay of timber ; they are simple, logical,
economical, easy of adoption aud perfectly innocuous. By em-
ploying them we shall save that tiiuber for building ships which
in my opinion, far supenoi; \fl \n)\i, tw \.\ia m-uih yuryoae.' "

m

Ge-v. Machtsery.] WOOD-WORKING MACHINERY.

I DIVISION NINTH.
_._...„,_ „
consent," saya an able writsr in the 'Engineer,' " to adopt
'tindard eizes and patterns of doors, window frames, sashes, shutteia,
-laircases, &c, a great field would be opened for the iutroduction of
wood-worting Eiaehinery. Mi'. Wliitwdrth, who has given so
much attention to the proper graduation of size in all the various
branches of the mechanic arts, observed, in an address delivered
in 1836 to the In^tttution of Mechanical Engineers, ' I think no
estimate uaa be formed of our national loss from the over multi-
plication of sines, • ■ • This question is also well worthy the
attention of our architects and builders. Suppose, for instance,
that the priucipal windows and doors of our houses were made
only of tliTBB Di foar difTereut sizes. Then we should have a
manufactory start up for making doors, without reference to any
particular house or builder. They would be kept in stock, and
made with the best machinery and contrivances for that particular
liranch; consequently we should have better doors and windows
ut the least possible cosi' In the construction of carnages, fui^
niture, &C, a determination on the part of the leading makers to
secure such a degree of uniformity as to pennit of the more
general use of machinery would result in a better quality and
lessened cost of the articles produced, just as machinery has im-
proved and great^ cheapened a large number of maiiufeeturea
formerly carried on by handicraft. There is still more or less
prejudice against machinery, and as for wood-working machines
they now cost heavily, although there can be no question as to
the excellence of tlieii quality as turned out by onr leading
makers As a rule our builders work rather barder and more
uo^ly woods and with less waste than the American wood-workers,
but the differences in the prices of the tools employed are extraor-
dinary. Let us take a rack circular saw beach. One, by a first-
class firm, with a rack-bed 40 &. long, 26 in. wide, and intended
Air a ffJi-in. saw, running at 600 ie\o\a'l.\oa&, u.\4<;^^lt^^^l't v

ENGlNEERINIi FACTS.

(DiV IX.

ip, wdglis a lona, anJ coats, exclusive of saw, £260.

portable circular saw mill, used in the States, lutving a
lO-in. saw, running at 400 revolutiuns, weighs l-J tons, and costs,
icIiistTe of eaw, £100. Here we have a, planing machine, with
both fixed knives and revolving outtera and side cutters, the whole
weight being sis tons, and the maker's price £380. The Ame-
ricans use chieUj revolving cutters; and with these their Wood-
worth planing miichines, with iron frames, 13 ft. long, planing
24 in. wide, and having top and bottom ontteis and grooving
cutters, end made throughout in the best style known in the
States, cost £190. A class of machines on the same principle,
but having wiKjden frames and deaigued for planing narrower
boards on but one side at a time, costs £l 10, and is largely used
in the States, Mr. WhitWOTth found them planing boards 18 ft.
long, and varying from 3 in. to 9 in. in width, at the rate of 50
per miuute. The cutter heads had three cutters, the circle
iribed by the cutting edges being 12 in. in diameter, and the
' IS 4,000 revoUitioDH, or over 12,600 ft. pw minute. Mr.
'Whitworth was informed that the cutters only required sharpeu-
ing with the oil-stone once for evei^ 2,000 ft. tfl 3,000 ft. of
work, anil grinding once for every 20,000 ft to 30,000 ft. Onr
best makers charge £200 for a planing, surfaciog, and squaring-
Hp machine; and where made donhle, to take two pieces of tim--
faer IS in. square, the price is £325. A machine for the same
purpose, and known in America as the ' Daniels planer,' planing
42 ia wide and 60 ft long, costs £102 ; while that planing 16
in. wide and 20 ft. long costs but £42. The beat power mor-
tising machines made in the States have also a boring spindle,
and the chisel is worked through a link in such manuer that,
jWithout interfering with the driving power, the stroke may
itantly adjusted from ^ in. to 1 ft. by the pressure of the foot
treadle. Those machines cost from £26 to £66. The
irgest and best mortising macliines made in Xioudon cost, with
iring apparatus, ^£200, the smaller machinea costing from ^80
£100. Without extending the comparison we may say that
lihe prices of wood-working machinea, such as are used through-
out the United States, vary from one-fourth to one-half those
wliieh prevail here for mochinefi intended to turn out about the
same or possibly a Mtiboi \a!fg,6i t^iaiaViilEs tA ■»iti£s^

Ges, Maobinkbv.] WOOD-WORKIHO MACHINERY. 383

some cases t>LS Auteiicaii tools are mode to turn out inon; work
than ours. The American wood-working machines have gener-
ally had wooden £ramea, but this does not account far their cheap-
ness, for where iron frames are adopted, the price of the machine
is but very little more. The framing ia, however, very much
lighter than our own, the whole weight of the macliine licing
always much lesB, The American machinists insist, however,
that their wood-working machines are amply strong, and while
they are doingprobaT>ly a hnudied-fold.if not a thousand-fold, more
wood conveiaion than is done in all the rest of the world toge-
ther, they could not be induced to adopt our proportions.

" Wbile upon the subject of wood-working machines, it may
be interesting to state the actual standard thickneaa of the cir-
cular sawa used by the American sawyers. For from 4-iii. to
5-in. saws. No. 19 of Stubs' gauge is the thickness employeil,
from 6 in. to 8 in. Na 18, 9 in. No. 17, 10 in. and II in. N...
16. SawB of from U in. to 16 in. are of No. 15 gauge, 18-iii.
sawa No. 14, 20-in. No. 13, while from 22 in. to 26 in. the
gauge is No. 12. Saws of 28 ip, and 30 in. are of No. II, and
from 32 in. to 36 in. No. 10. From 38 in. to 42 in. No. 9 is
adopted, while from 44 in. to 52 in. a gauge of No, 6 to No, 7
ia used. From 54 in. to 68 in. the gauge is from 5 to 6, ami for
saws varj'ing from 5 ft. to 6 ft. in diameter, a uniform gauge of
No. 5 is adopted These thicknesses are rather less than the
Americans have been supposed to use, although it is the fact that
they do occasionally run thicker sawa, especially at the high
speeds of li'om 12,000 ft. to 16,000 ft. per minute, which they
often employ. A 5-ft. saw, which costs here £18, costs £36 in
the Status; a 4-ft. saw costs ^7 10s. here, and ;C12 lOs. there;
ii 3-ft. saw costs £i in both countries, while saws under 3 ft.
iMSt less in the States than here.

" It may bo that the band saw is destined to bo much more
used than heretofore fur heavy sawing. Mr. Wnvssani, we be-
lieve, has fitted it to some of his heaviest rack saw benches in
conjunction with the circular saw, and for cutting logs up to 42
in. in diameter. For reciprocating saws a steam cylinder can he
fitted tlirectly to the swing frame, something on the plan patented
lost year by Mr. Greenwood, but with provision against the sbiik-
iug of the piston or swiug frame, no matter how audUenlv tlie

ESGINEEKING FACTS.

[Drv. IX.

esistftiicc to the saws might be removed. Thus the piston sliould
a trunk on its lower Bide, leaving an area upon which the
ire of the atoam ehoulil he alwaya sufficient to cany np the
■awe and frame, ami upon this area the steam should he alwaya
fessing, no exhaust taking placp, the area of the whole upper
e uf the piston being atich that the steam should not only
y down the saws, but overcome, also, the constant pressure
n the lower side. The cylinder could then be made of any de-
red length, without couaequent waste by exhauatiug a large
i of steam from below at every stroke. A steam-moved
|-walve, of the same form as the main trunked piston, and having
Wt constant pressnre of steam on its smaller area, might be easily
pttod so OS, without any valve giMir, to regulate the admission and
^hauat of steam to and from the top of the piston, and this
■ iCOuld easily be arranged to give any required stroke to the latter,
and that always without waste of steam. The cheapest and best
reciprocating saw-mill which could possibly be devised might, n
believe, be made on this plan,

" There is a useful tendency tg combine upon the same Irame

ore of such machines as are not required each to be in

■.constant use. ITius Messrs. "Worasam's ' general joiner,' on a single

f firame, and for ;£S5, serves the purpose of, at least, five distinct

achines, which, if constructed and sold separately, would cost

a ^6300 to £400. This kind of combination can, doubtlees,

e carried out with advantage in the case of other machines.

"The rejection of needless weight, unnecessary finish, and
tounilahout combinations of parts and complicated movement^
fwill lead to the production of a class pf wood-working machines
much better adapted to the general wants of engineers, manufoe-
Wrers, and builders. American machines furnish, among others,
e instance of such useful simplicity which we will notice and
which deserves to he copied. The journals being turned, they
e placed in cast iron boxes, recessed out ao as not to t«uch the
fenished surface hj i in. or so all round. Into this
_» composition of 100 parts tin, 10 antimony, and 2 of copper,
fwhieh forms a perfect wearing surface, and which may at any
time be cheaply renewed. The composition lining is, of course
divided to serve both halves of the plummer hoic. Where lateral
motion ia especially to be gu^■c4el q;^\i««., 'Ont \c\irwii. v

^Bi. SlACBiNEiiT.] WHEELCUTTISO MACHINES. S.Sn

Lurned with a nnitiber of circular V grooves, each forming a c<il-
lir like (he thread of a screw, or like those in Mr. Rotertwm's
Itictional wheels, and the conijioaitiun already descrilicd is then
cast arouitd the journal thus formed. This simple and incxpca-
sive practice gives results not to be attained with fifty times the
expenditure of money on iither plans. This U liut one illustra*
tion ol' the kind of inijirovenient to wliich our wood-working
machinery must he sulijeeted hefora it can ever be used ti)
.itiything like the extent of machinery fur a like purpose
abroad."

WHEEL-CUTTING MiCinNBS.

3 scarcely iiecesaary to urge upon any practical mechanic
k great value of a good wheel-cutting machine. It is well-
D that tbia deacriptiun of special tool was amongst the first
IShinea that made their appearance in English engineers' work-
Messrs. Fox, of Derby, appear to have been the origiua-

jTin England nf an engineers' tool for cutting and dividing

I teeth of wheels. Brass wheels, and wooden wheel patterns

k Bmaller diameter than nix inches, and of fine pitches, liave

Kir rinia generally east to the depth of their teeth, which ai'u

divided and cut out of the casting by the machine. Circular, or

rose-^juttera, are often formed in the same way.

" If a cast-iron toothed wheel be oast perfectly true, it is, of
course, better to leave it untrimmcd. To take the skin off a
casting always reduces its strength, but it aJso diminishes the
duration of the teeth of a wheel The skin on u casting is
niewhat like the skin produced by case hardening a piece of
ight-tron. For rnany years Mr. Whitworth has turned out
I change wheels of his lathes, &a., without any trimming.
r wheels, however, are often trimmed up, as it is not so
T to cast a large toothed wheel quite true, Tlie wooden
9 of mortice wheels are also generally shaped by hand, and
nore especiaUy the case with the cogs of bevel gearing.
I wheels intended to work with mortice wheels, gener-
ally have their teeth trimmed up by hand. This is a costly and
tedious operation, but its necessity is apparent. The wooden

I
I

^ase ENGINEEEING FACTS, piv. IX.

cogs of a mortice wlieel wonld be speedily wom away by the
rough Buriiicfl of cast-iron teeth,

" Steel circular cutters of tbe exact shape of the looth are
generally used for cutting epur wheels. It will be see
that it would be impoBsible to cut a bevel tooth by m
circular cutter, without Betting the cutter at an angle, TliB
teeth of a bevel wheel of courso advance and recede, both Eis to
depth and breadth. Even when a correct circular cutter is need,
the wheel is not completely finished by this procesa; it most be
trimmed up by hand-liling. It is acarcoly possible to get a cor-
rect bevel wheel by means of a circular cutter,

" In our number for October 24th, 1862, p. 253, under the
heading of ' Machine-tool Substitutes for the File,' we alluded at
some length to the subject of circular cutters, and we there pro-
posed to make a circular cutter for tion upon the aame plan aa
the cutters used in ' £icldell's ])atent oat-miUs.' It ia evident
that the circular cutters used for wheel-cutting machines might
be made in the same way. Circular cutters, formed of one piece
of steel, often Bpriug while being hardened, and are also very
liable to warp wiiile undeigoing this latter operation. When in
use, should any teeth be brokea off, the whole cutter must be
tui'ned up, softened down, and recut. There is also a dilSculty
in sharpening the edges of the teeth, when the cutter gets worn,.
Mr. James Naamyth, of Patricrift, some thirty years ago,
circular cutters out of a number of separate knives, in tbe fal-
lowing manner: —

" He built up the circular cutter out of a number of separata
steel cutters, the inside of each cutter being of a wedge ebapc^
and the whole number required were arranged in railii from th«
centre of the disc. A wrought-iron ring was shrunk on the ar-
cular bundle of cutters, so that it could he turned up
lathe, just as if the cutter wore in one solid piece. One aide of
the cutters is first turned up, and is then fitted into the chuck
of the circular shaping or wheel-cutting machine. The chuck is
furnished with a set-screw, and tlua screw is caused to press
upon one 'of the separate cutters, which thus acta as a wedge
between the other cutters. The wrought-iron ring is tlwo
knocked oS, and the other ^tt of th« circular cutter ia tunwil

mw

t. KiOHlUMT.] OUTTEBS OF WHEEL-CUTTING MACHINE

F

^^P in the lathes^ so that all llie aepaiate knives or cutters are of
the same shape.

" On slackening the set screw, the separate knives can be
ensily taken out of the chnck, and filed up to the reqaired shapi-.
On being properly hardened, tlie knives are replaced in the
chuck. Xbey are then screwed up by the set screw, and the
whole circular cutter ia thus ready for use, Before the modern
impioTenienta in moulding, enabliug us to cast wheels with
greater precision, wheel-cutting and dividing machines seem lo
Lave been in greater demand than at present We have aeen,
in an old German periodical for 1843, a design for forming a
circalar cutter for toothed wlieela, upon a plan somewhat Bimjlat
to that of Mr. Naamyth. The German design was avowedly
s^^geated by Mr. Nasmjth'a cutter. A circular cutter tor the
teeth of wheels mnst, of course, cut on thre.e aides, taking up the
sides and bottoms of the teeth. Thia kind of circular cutter
must also be fixed ou a mandrel, and requires to take the shape
«f a wheeL It is thus impossible to fix such a cutter on the
chuck of a hithe- it must bo independent of all such support.
The way described was the following ; — The separate cutters
were filed up to a wedge ahape, and arranged in radii together;
wrought iron ring being then shrunk cm the whole. This steel
disc was then placed on a lathe, and the centre bored out to the
size of the spindle upon which it was to be fixed. The disc
was then fised on a mandrel, pruperly turned np to the required
shape, and a cireular groove was then formed some distance from
the centi^ This groove was made of a conical or bevelled shape,
and a ring was fitted into this groove. The ring thus keeps the
separate cutters together, when the out:jide ring was taken oif.
If this inside ring be once tightly driven into the groove, the
Dutaide ring can then be token ofi'. Tlie steel di»c or cutter is
then placed on a mandrel, and turned up in a lathe to the re-
quired shape, There is a boss on the spindle of the circular
cutter, and a nut ia screwed up atj.iinst the other side. The
separate cutters aie thus kept from being pressed out. These
independent cutters can alao he separately taken out, sharpened,
faid hardened, just like Mr. Niismyth's cutters.

" In our volume for 1849 will be found a self-acting method,
JKwosed hy a student of St. John's, Cambridge, for cutting t

ENGINEERING FACTS. [Div. IS,

^■^ 333

^^H teeth of the drivers of pin tvheela or trandles. AVc do not know

^^B whether this plan has ever been carried out.

^^1 " There were three machines in the Iiit«mational ExhibitioD

^^P for cutting the teeth of wheels; two of these used circular cut-
ters. One was exhibited by Mr. Whitworth, of Manchester,
and figured in the western annex. The second maebin
uesit hy Cook and Sons; it waa intended more especially for
horological wheels, and was on the same general principle as
Mr. Whitworth's machine. The machine exhibited in the In-
ternational Exhibition by Mr. Whitworth, was intended to cut
apur, bevel, and screw wheels ; in metal or wood. It could cut

I wheels up to ten feet in diameter. This machine consisted of a
long bed, similar to a lathe bed. A circular cutter was used,
which waa iuteaded to te net at an angle when bevel wheels
were required. The circular cutter was on a vertical apindle,
wurkiug in an adjustable head-stock. The speed of this cutter
could be varied to suit wood or metaL The wheel to be operated
upon was fixed on the end of a mandrel fitted .'
bracket. There was an ordinary dividing apparatus for pitching ■
the teeth. This machine is amongst the best tools of Mr. Whit- 1
worth. It no doubt does its work very efficiently, with respect.!
to spur and screw wheels, but it is subject to the objections we ¥
have previously alluded to; when speaking of cutting out bevd I
wheels by means of a circular cutter. The third wheal-cuttiiig
machine was exhibited by John Hunt and Co., of Bow. ~~

^lutve also heard of this firm in connection with anti-frictioa J
metal boariugs. It was a special tool for dividing and cutting 1
bevel gearing. Although in an out of the way comer, it excited I
some attention, from its exquisite ingenuity, and as an example ^
of tight adaptation of means to an end. The attendant asserted 1
that the machine cotdd pitch and trim more wheels ta one day I
than could be achieved in a week by a good millwright. The I
apparatus conflists, essentially, of a shaping machine with a
^L procating tool. This tool has a stroke of about three inches. I
^^L The slide is made upon the plan first adopted by Mr. Nasmyth,!
^^ft of Fatricrift. The tool box slides on a top and bottom Y, audi
^^r is therefore less subject to any side deviation through wear, f
^^r la iront of the tool ho\iiei atc tfo fitted bearings, carrying a crosc.l
^■hlAflft, through the centre o^ w\i\^ \a awiejjft."w3^a!a!4,».

OltN. JUcHlNEBT.] TOOTH BHAl'lNG MACHINE, 383

f .On the bottom enii of this maniirel is fixed the wheel or pattern
D be operated upon. On the top end is adjusted the dividing
f apparatDs. This mandrel has a motion in a vertical
.nd another motion horizontally; out of a composition of
I two movements the varying depth and hreadth ul the
bevel teeth ai'e produced. The vertical motioa is obtained by
of a worm working ia a tpothed segmeiit. The feed mo-
i commnnicated by a cam on the driving shaft, working
Ento a racliet wheel. Tlus wheel in ita turn works the worm
I segment. The depth of tooth for the hevel gearing is thus
Obtained. The form of the teeth ia produced by means of a
^er attached to the mandrel on which the work is tised. In
) oth<^r end of the lever is fixed the shape of the tooth upon
' Bomewhat increased acale. This templet acta against a steel
might edge on a line with the tool The vertical motion
acting upon thLs lever works the tooth duwn, and thus trans-
mita the motion from the templet to the tooth of the wheel
being produced. The templet ia kept against the steel straiglit
edge by meana of a spiiiig. Tbera is an ingenioiia spring and
detent motion, throwing the vertical movement out of gear when
the tool reaches the bottom of the tooth. The dividing plate,
to which we alluded before, is set by hand when each tooth is
finished, and it is kept in position by a lever and point. This
lever is adjustable, in order to regulate the thickness of the teeth.
The pitch ia given by the holes in the plate. After cutting one side
of the teeth, round the whole cireumference of the wheel, a left-
handed cutter is substituted for the previous tool, which we.will
suppose to have been right-handed Tlie templet or ahaper i

changed to the other side. The machint

on to complete the shape of the teeth.

In our volume 52, for 1850, p. 97, will h

kxtracted from the 'Franklin Journal') of 'a

1 for bevelled gear' then patented in Amerii

isa. The machine is not illustrated, but, e

lered from the description, ita principle is slightly similar tn

; machine of Messrs. Hunt and Co. 'A recijirocatiiig cutter

lat moves in a slide is used, which cutter vibratos on an axis

jides, or nearly so, with the apex of a cone representing

o£ the whetA to be cut, vai^ \n v\ciSa.-r'

foimd an account
iiachine for cutting
rica by George H.
} can he

1

KSGIKEERING FACTS. [Div. IX.

depth of the cut ia detennined.' It is thns se:ii that tlie renpro-
catiiig cutter is adjuatatle.

" The tcork is wljustahle in Messrs, Hunt and Oq.'s

ment. — 'Mechania! ASaQOzijie.'

On the application of machinery to eoal-cnttiug, a paper was J
read hy Mr. Samuel Fii-tli before the British Association, of which I

I the following is au estract ; — .
" While excaratiiig machiuery is used with suuli ancceas in the I
>great Mount Cenis Tunnel, it is not too ranch to expect its early I
introduction into our mines, under circutnstances certainly not I
more difficult. Mr. Firth, in the coarse of his paper, said :-
" Numerous efforts have been made, dnring the last fifty years^
to bring coal-cutting in mines under the influence of mechanical
power; but in no case, I believe, except at the West Ardsley
Colliery, has any continuous operation survived the experimental
" I do not expect that the introduction of machinery into coal
mines for the purposes named would ninti-rially diminish the
OTinber of persons employed, but rather that the effect would be
to meet the increasing consumption. That increase may safety
be taken at two millions of tons per annum, and to supply this
increase would require an onnnal increase of labourers amount-
ing to about 3,500. Thus there will not be any displacement of

" The steam-engine has a 20-inch cylinder, and the air-pamp
18 iu. The air is worked at a pressure of about SO !b. to the
square inch. The air is conducted down the sliaft in iron pipes
of 4 in. diameter, and thence to the workings (about 800 yds.^
in gas piping, and down the face by india-rubber piping ckE
1 in. diameter, which is connected to the machine. The machine
is moved on iron rails laid on cross iron sleepers, and is propelled
a little, after each blow of the pick, by the hand-wheel. Gener-
ally, the machine is passed three times over the face of the coal,.
each time with a longer pick, to gain the requisite depth for tak-
ing down. The first cut being 18 to 20 ia, the second 9 to 11
ia., and the thiiJ from 6 to 8 in. ; 3C in. being the depth aimed
nt and accomplished- The actual quantify of work done ii
consecativa days of eight \ionTa 6a*i\, t^ one man with one ma-
cbine, waa 6184 J'^^-- °'^ »bo'^ *^^ "^^^ '^ '^'^^ "^^ie, isaa.'-<»

Gek. MACHnrajir.] COAL MINIira MACHINE. m

attended by two boys, who cteoa out the groove, and reraoye the
GOEtl thrown out by the macblue. In the West AnUley eeam a
man will average 7^ ydfl. of coal o-day, so that if the machine
were worked by shifts of eight hours, three men and six boya
would do the work of forty oien, and that, too, the most severe
and trying work in the pit

"It must be understood that at West Ardsley the seam is
somewhat favourable for the purpose. It ia 4 ft. thick, having
a. good roof and floor, and is worked on the long-wall aystem,
with a somewhat soft bareing part, about 12 in. above the floor,
and in thb the pick works. The comparison, however, with
handwork is fairly mode, because both work in the same part of
the seam. The machine thua far has only been put to ' bare-
ing," or 'kirTing,' but the proprietors expect to efieot 'straight-
work' by a different arrangement of the picks. The filling, and
all other work of the pit, is untouched by this machinery. The
air-power works admirably ; and its use gives a cool and refreali-
ing stream of pure air to the far-distant works, which issues from
a cylinder at a temperature very little above freeiiny-point. It
*1 not be necessary to say here that the air-power is acquired
&a much larger measure of steam power ; but this ia not a ma-
ftial item at a colhery, where so mach engine coal is almost
I am not prepared with the exact commercial results
■ saving in cost, but at West Ardsley this part of the question
|I believe, eminently satisfiictory. I have been informed that
e experiments have been made, within the last few days, at
B Hetton colliery, by the West Ardsley machine ; and although
<e seam is of a hard nature, the kirving was done 3 ft deep
ith a groove of 3 in. at the face and 2 in. at the back, giving
B average cut of 2^ in. high ; whereas the average height of
d-kirving in the same seam is about 1 1 in.
"This saving of good coal from destruction ia equal to an
erage of 94 per tou upon the whole yield of the seam.
"Another machine of a different principle has been invented
I West Ardsley, and promises to be a most useful one. It ia
B the direct-action principle, with a to-and-fro motion, from n
l^linder mounted transversely upon tlie carriage, and regulated
a similar manner to the pick machine.
"Tfaia inventiiin lias not advanced ao fei a& ttva ' ^w.t^ Wt.

^KBome recent experiments have given most satisluctory results.
^BXlie complete success of this machine will l>u of great impoft-
^Hfnoe, as it will be more eifective in 'straight- work,' 'headings,'
^F uiJ ' drilling,' than the pick.

^^ " In ooncluaion 1 may express the confident opiniou that, at
no distant period, every branch of mining will be accomplished
by machinery ; and if we look at those results froui
point of view, the sooner they are reulized the better it will be
^L fur all parties, and espeiiially lot the working collier."
^H We ourselves have repeatedly seen this machine iu operation,
^V anditia truly wonderful how simply uud efficiently it does its work.
The mochiae ia so hght ami compact, that, if by any means the
small wheeb get off the rails, one man can with great ease lift the
one end of the machine and rpplacu it upon them. 'She machine
! we saw was one of the oldest and most used, and was literally
L covered with coal dust, and apparently had not seen a piece of
I its erection ; withal this, however, its action
a perfect, and the work was done apparently as well as if the
■.machine had been made of the best workmanship p;)SBible. The
■admirable fitness of compcessod air for working those mocluQes is
Witll the more marked when wu consider that the exhaust serves to
■Tentilate the seams. Other work is done in the West Ardsley Fit
ueans of this compressed air, instead of using horses, or In some
s boys and men, for propelling the trucks along the seams, a
11 winding engine is employed, worked by air, thus saving
h laboiu- and expense. The only defect in the use of com-
pressed air to propel such machinery ia the small percenter of
power realized from it in comparison to the force required to com-
press such air. This is principally owing to the diiKeulty in utilit-
t ing the whole of the expansive property of the air in the coal ma-
ihinery, while in compressing it all such expansive property oQsn
II resistance in compression. The loss aUo of latent heat is
mother source, as also friction, in compressing, &a. With all this
's not much more than 40 per cent, reulized, and this under
rourable circumstances only. A good air engine will materially
iduce this loss, but when done, it is of little importance at the
pit mouth where abundance of ilack and other refuse capable of
producing ateam can be obtained.

a the ajipUcatioTi. oS. fti^ voadoiQKri ^ *iW Wuat

ENGINEEBENG FACTS. [Dit,

F

MAOHtEEST.] BOOT AND SHOE-MAKING MACHINE.

'AnMey Pit that we <lo not consider ourselves too eangaine is
cherishing the belief that in a few yeura the great bulk of tha
work ill coal and other mines will he all accomplished by its
aid, and this accompanied by a great saving of money, and
what is of atill vaster importance, a saving of human Ufe. Ee-
cently, owing to the acareity of labourers in America, machines
have been dent out there, and there is every reason to believe
that they will he generally adopted wherever they are at all ap-
plicable.

Bool and shoe tmlHng has within the last few years been

greatly accomphshed by machinery, — Huch machinery complet-

ig the work and leaving almost nothing to he done by hand.

America this machinery has been carried to the greatest

ite of perfection, owing to the demands of the war and the

ity of labour. The ' Scientific American ' thus describes an

iblishment fitted up with such machines ; —

Three large apartments are occupied by the operatives, mo-

and goods. The skins for the uppers are fiist spread

itj examined, and selected according to the purposes for which

required. DUferent cutters then out out the respective

Lrte according to the size and form required, and these are all

loged and classilied. After this, these separate parts are given

lots to be sewed by machines, and those uppers which are

itended for boots are crimped, and the whole made ready fur

iving the soles. Tlie more heavy operations of punching,

'ing, pegging the soles, and finishing the articles are next exe-

Tbe sole leather, in hides, is first steeped in a tank of

it*r to soften it; then it is thoroughly dripped, and afterwards

It by a machine into measured lengths of a certain breadth,

irding to the size of the sole wanted. After having become

l^iently dry, these cut strips of leather are run between, rollers,

id also submitted to severe pressure under plates in a press, so

me to effect as complete a compression of the fibres as is attained

according to the old mode by beating with a hammer upon a lap-

stona From these compressed strips, soles of the different siuea

punched out at a single blow by a machine, the cutter of

which is of the size and form required, and it turns round so as

cut a right anil left sole alternately. Heel-pieces are also cut

iff boUow punches at a single \i\ow, tVia ai^ta-AMiiawi

I

I

ENGINEEKINQ FACTS. [Div. IX.

and IimIs are next amootliod aiid polished in a amoll rotating
machine; and another machine then makes the channels in the

soles for the rows of stitching. After this, the under solte and
uppers are fitted upon lasta and made ready for sewing. This
nperation is executoil by Mackay'e peculiar machine, adapted for
tills specific purpose. The waxed thread ia wound upon a ver-
tical spool, and is conducted through a guide situated on the top
of au elbow secnred on a awivel joint capable of turning under
the needle, and conducting the thread into the crease around the
sole. The needle operates vertically above the sole, and the
waxed thread is fed into the interior of the boot or shoe by the
guide, the needle descending through the sole, drawing through
the thread and forming the atitehes, which are pressed down close
into the crease by a tracer-foot, upon which great pressure is ex-
erted. In this maimer the sole and upper are united firmly and
neatly together in a few seconds, without employing a welt
Hand-sewing cannot be compared with such machine-work for
accuracy and rapidity. Another machine is enjployed for putting
un Uouble eoles with copper pega. A thin strip of cuppsr ia fed
in at one side and the holes are punched in the sole, the pegs
cat and put into the holes, and then driven down at one con-
tinuous operation, with a speed corresponding to that of sewing
the soles. The crossing of the half sole at the inatep is pegged,
and also fastened with a screw at each side hy hand; the heala
are also pegged down. The edges of the heela are neatly trimmed
by a small rotating machine, and the soles are also rubbed down
by a machine; so that nearly all the operations connected vrith
the manufacture of boots and shoes in this establishment are
performed by machines designed especially for the purpose. The-
legs of the boots are stietehed and the wrinkles removed by new
boot-trees secured to benches, and are expanded in an inatant from
the interior by pressing on a treadle with the foot. Theae boot-
trees are altogether superior to the clumsy old wedge kind. The
materials used in the manufacture of these articles appear to be
of a superior quality, the machines not being adapted for operaU
ing on inferior patch leather. Another novel feature connected
with these machines is that they are driven by one of Iloper's
hot-air engines, illuatrated on Tfii^ ^^i ^°^ VUI. (new series)
of the ' Srientific Amerieo.n': IX. taa 'Weii. TOnmat "isn. ws««t^

r

Gen- MACHraEiiT.] TYPE-SETTING MACHINES. S96

months, reqiuriiig but little attention and consuming a very smull
quantity of faeL The accurate operationa of these machines and
the rapidity of their action place them in a highly adyantageous
poaitiou for manufacturingi boots and fihoea. The price of hand
labour had become 8o high, and worlnuen ao scarce, that such
machines became a necessity, and the change etfected by their
use is equal to four times the quantity of work executed by band
labour — that is, one hundred men will turn out with these ma-
cbinee as much work as four hundred men without them. The
saving of labour to the country is therefore immense. About
600 pairs can be turned out ilaily in this establishment. Per-
iJiape no labour connected with boot-making is so severe as that
"" iwed upon burnishing the heel with a warm iron. Thia

irk is still executed by hand, hut a machine is now being set
\p to acoorapliBli this finishing operation, and it will eoon be

work."

Tj/pe-aettinff machines. — "A lecture was delivered on thia

ibject, on the evening of the lOtb inat, at Stacy Hall,
^Boston, by Charles W. Felt, the inventor of a type-setting
machine. It was given before the Boston Printers' Union,
by invitation. Alluding to the efforts made by others re-
cently to facihtate the composition of type, he said : — ' Thomas
jr. Rooker, and John H. Tobitt, of New York, and Mr. A.
H Bailey, of the Boston ' Transeripf,' were mentioned as
having devoted more or leas time to improving the prevailing
methods. Mr. Kooker has introduced into the ' Tribwna ' office
forty cases with moveable bottoms. In these cases the bottoms
may always be kept conveniently full in composition, and in dis-
tribution the bottoms may be lowered so as to receive a large
itity of type. Mr. Tobitt's plan, and ulao that of Mr. Bailey,

that of uniting two or more letters upon one body, ao that by
lift two or three letters are set up instead of one. Mr.

iley's system of combinations is calculated to save from 20 to
40 per cent, in composition. When it is considered that the
■word t/ie forms six per cent, of the language, and and about four,
while many others exceed about two per cent, the advantage of
R combination system is evident. The difficulty in tlie matter,

Mr. Felt alleges, is as to how many and what combinations
be used with profit. The ubq oi I'j^^'iKft'^ ■Kia!ii\Ess^=i,

ENGINEERING PACTS. [Div

^^f vos claimed, would add 25 per ceut. to the earninga of the print-
^B ei) but the stronger argument in its tavour is that it will add
^H 25 per cent, to his liie. Though the subject of combination t;pe
^r is one of primary importance, because ao simple, and beoause
yielding a gain which is a proht of itself yet the great reform
printing is to be made bj introducing machinery. In all ma-
chines hitherto invented no attempt has been made to justify.
The possibihty of justifying by machinery has long been doubted,
but Mr. Felt contends confidently that there i^ no im{M)6sibili^
in the case. The types are aet up in bis machine in the usual
order as the keys are touched, and the words are separated, not
by the usual epacea, but by piece.i of steel with beads by vhich
they may be drawn out.'' — ' Scientific American.'

Coming now to agrieultural implenieiiU and machine» we

» propose treating first of steam ploughs, an invention of compera-
tively recent date, but one of considerable importance and int^^st
to the agricultural engineer and the public
To do this most effectually we shall simply confine ourselvea
to the consjdijration of such facts as have elicited themselves ftt
trials, &C. That the history and nature of steam plougliing may
be better understood, we quote the following article &om thi
' Mark Lam Exfiresa:' —
^L " Steam ploughs may be divided into two classes — (I) thoae
^H only adapted for ridge ploughing, and (3) those constructed for
^H one-way ploughing, i. e., for laying the furrow slices all in oni
^H direction, thus leaving the ploughed laud without open furrowi
^H or ridges.

^B " Of the former of these two cinsaea little now requires to be
^H said, as the thorough drainage of land has rendered the latter
^H preferable. But when steam ploughing was first proposed, and
^H indeed up to a very recent period, ridge ploughing was essentially
^H necessary to effect the surface drainage of a lai^e area of land
^B HO that steam ploughs had to he constructed for this kind of
^H work. To overlook this fact in our notice would be doing an
^H act of injustice to several of our most talented pioneers who
^H m^t the contrary at our hands.
^B " Of ridge steam ploughs, for ploughing land lying in ridge%
^K aad for drilling fur turnip, we maY mention thoae of Major

w

™ Tiatfinti

r. Machisbet.] STKAH PLOUGHS, 897

patented ia 1839 and 1840 (the former No. 8,108 and the latter
No. 8,517); Clnrke, Freeman, and Varley, 1846 (No. 11,077);
and Osborn, 1846 (No. 11,304). Into their mechanical details
it would be a waste of time and space to go. As old paleute,
those of Ciiiupbell and White possess the most merit aud atten-
tion of inventors,

" One-way ateam ploughs liave been constructed on two plana
— (1) the two seta of plouyhs being placed heel to heel, and (2)
the two sets placed share to aliiire. The lalter only merit a de-
tailed notice. To the former we shall merely reftr, as in the
case of ridge ploughs.

" Of patented steam ploughs, the two sets placed heel to heel,
those of Major Pratt and Oshom above, aiay be mentioned, and
wore recently Lacy in 1855. Of those reduced to practice not
under patent, the example of Lord Willoughhy de Eresby merits
the most favourable notice. The chief difficulty experienced is
the position of the furrow wheel of the carriage ; but into details
of thiia kind we shall not ent*r, as the system has been super-
9$dgd, at least for tlie present.

" One-way steam ploughing, as now practised by those using
Fowler's steam plough, haa many things to reoc-mmend it; and
the first implement of this kind on our list of patents is M'Eae'e.
It was successfully reduced to practice in Scotland, being con-
structed on a plan differing in several parts from what is repre-
sented in the drawing accompanying his specification (No. 8,329,
A.D. 1839), and was shipped to Demerara, But, previous to this,
various propositions were enunciated for plonghing land on tliia
plan by agriculturists, engineers, and others; and of these one
was patented by a Mr. Pinkus (a.d, 1839, No. 8,207) resembling
in some points that of M'Eae's. The latter, consequently, in the
reduction of his proposition to practice, had to avoid the infringe-
ment of the former's patent, and it will therefore be necessary to
notice the peculiar claims of Pinkus' implement, so as to be able
to solve the interesting problem as to who is really ' the father
of the steam plough,' and also to establish a no less important
question as to what is public property in the steam ploughs now
at work in oui' fields, and foi' which fajmers are called upon to
pay long prices.

"JU>: Pitikua had two patents — ^ &\k>\i& '^oa^ ^g«»:«ij«&,

~m

388 ENGINEEBING FACTS. [Div. IX.

M'Bau's, aod another in 1840 (Xo. 6,644), In neither case
doe^ be lay anj claim to novelty in the construction, of his
pluugUa Indeud, between 1831 — when the committee of the
Hotiae of Commons gave to the public its memorable report in
favour of ateom- locomotion on common roads — and 1840, steam
ploughs actuated as proposed by PJnkua was the cummoa con-
versation of hundreds of intelligent farmers, whenever they met.
In tbe ' Quaxterly Journal of Agriculture,' vols, v., vi., and vil,
the subject will be found disouased in a series of able articles,
includiug a full account of Heatbcoat's expeiiments of steam
ploughing at Red Moaa, Burton -le-Moiira (vol. viL, p." 227). In
vol. v., p. 480, reference is mode to a Mr. Thomas Gibba, who
had a moitel of a ' travelling steam plough,' and ako a rope
system of hauling, or, as it is there called, of ' towing ' steam
ploughs between two engines, one on each headland. But^ how-
ever interesting a detailed account of sueh would be, oar limits
will not permit us to go farther into the histoty of the steam
.plough and the rights uf the public,

" Pinkua, in hia specilications and drawings of both hie
patents, merely gives a popular outline of what M'Rae or any-
body else may do, without iniringing existing patents. In other
words, the mechanism of his plouj^ha and luode of yoking two
.«ets below a carriage-frame borne on four wheels, one sut for
'ploughing one way, and the other the opposite, were then public
'property, and, hence, cannot now be claimed by grasping and
monopolising patentees, so as to prevent others improving such
mechanism and modes of yoking, thereby going ahead and leav-
ing them behind in the march of prepress.

In both drawings only a part of the implement is shown,

while that portion ia not drawn to a scale, so that they are nut

ily mechanically defective, but wanting in detul ; consequently,

requires to he acquainted with the progress of tldngs at tlie

period, to understand the drawings of either patent.

"The object of the patentee (Pinkua) evidently appears to be
the illustration of variety, the two sets in tbe drawing of the
first patent being mechanically unlike each other, while both
widely in niechanicai construction from the two sets of
loughs shown in hia patent of 1840. In the former, from ro-
being made to the Wnfiioa Qt ^\QM.'^"S.a. "t,'*. Vs, 'sumi-

Ges. Machinbkv.] steam PLOUGHS. SUB

feat that each plough had au individual action, and was held liy
its owu ploughman. On teaching the headland the copse of the
plough is screwed up to the frame hy the attendant on the cor*
rioge, 30 that the plough would heel out, as iu the ease of the
common plough. The three ploughmen would then Ms up their
ploughs to the framing hehind, as ehown in the drawing; thtn
go to the opposite end of the carriage, and let down each hia
reepectivB plough for the reverse movement. Now, this, at the
time, was a very common piopositioTi. Iu the second patent,
again, each set of ploughs is rigidly fixed to a diagonal l^, the
four ploughs in each having a common heam. This is neither
more nor less than a four-furrow ' Somerviile plough,' as they
were then called, with a common beam under the caniagB so
as to expedite the acrewing-up of the copse, to take them out
of the ground and let theia into it with equtil despatch. This
waa also a very general proposition hetween 1830 and 1840,
but objected to as involving a sacrifice of mechanical principle,
and what is worse, the subjecting the famiur to hard work at
each headland.

"Thishighlyobjectionalilefeatureof rigidly fixing the ploughs,
either in a frame or on a diagonal beam, so as to enter together
at the one headland, and to bo taken out in a, similar mBnncr
when tbey reach the opposite, on the Somerviile plan, merits a
special notice, as it is now being generally adopted. Practical
(^riculturists have, fram the first experiment of the Somerviile
plongh, condemned it without ceremony, owing to the bad work
it makes at the headland — the loss being much greater than the
saving of manual labour counterbalanced. In horse culture this
objection to the Somerviile plough is unanswerable, and under
steam-culture a different conclusion cannot be arrived at either
practically or scientifically. We ure not insensible to the diffi-
culty of entering and taking out sets of ploughs, three and four
being in each set; but that does not justify the sacrifice of me-
chanical principle, nmch less the making of bad work at the
headlands. With the latter — bad work — farmers are familiar.
We never heard it estimated at less than double the ploughman's
,, about 5s. per acre. It is one of those valid objec
B to steam ploughing, as now performed, that greatly increases
»expeaae, aud thus stands intha^v; c^'^to^SREA. ^^tl^lG«.

ENGINEERING FACTS, [Dtv,

f

^^m former — the sacrifice of mechanical principle^-this we aboU
^^B unine under Fiaken's impleiu(>ut, aa our remai'ks will be better
^^m niiilerstood after noticing ^I'Ea^.'s Hteam plougli, which
^H from this cardinal objection.

^H "As the writer haa determined on having a steam plougli
^1 made on M'Bae'x plan, exactly almilar to the one that was nmda
^V by the Messrs. Thomas Edington and Sous, PhiEnix Ironworks,'
^* for the patentee, and succeBsfiilly trieil on the lands of Fossil,
near Glasgow, and worked by him on his own plantation estato
afterwards, in order to prove that hu (Alexander M'Kae, Ssq., of
the county of Demerara, British Guiana, planter), is the legiti-
mate father of the steam plough, a general description of tbo im^
plemeut ia all that will be neceesary at present, a promise being
given that a drawing of It, with the usual descriptive details of
its mechanism, shall be forthcoming at no very distant date.

" Like too many almllai' projects, M'Eoe's appeals to have
been patented before it was reduced to practicn. This, generally
(peaking, is a prudent course to pursue, and perhaps upon tile
whole tlie freest from objcctioa, ware patents less espenalve to
obtain; for, in the carrying out of auch projects, new discoveries
are often made in the manufactory and field, which require a

I second patent to cover them. And this was the case with
M'Bae's steam plough, for his specifications and drawings do not
whidlj cover it. In other words, the improvements made, when
his project was placed into the hands of the above engineers to
carry out, were such as to justify a second patent ; but the ex-
orbitant oharges of the Patent Office at that time, we presume
prevented this, and also the general public, irom getting the in-
formation which otherwise they would have derived from the
specification and drawings of the Improvements juat mentioned.
The loss thus sustained by the public may to some extent be yet
counterbalanced by placing a model of M'Eae'a steam plough in
the Patent Museum at Kensington ; and this national duty, we
hope, her Majesty's Commissioners of Patents will not fell to
perform, seeing that they have ample funds at their command
legitimately available for this important purpose — one whicli
could not fall to stimulate the progress of invention in steam
oultaie,
"Aeeoiding to the diawina ft^ aceamvMaaa "WBwi'

r^

Gen. Maohimkuv.

STKAM PLOUGHS.

mi

ficfttioa, a carriage-fmme suspended Iwlow llie axles is btirne oti

r wheels — two furrow wheels and two lund wheels — and la

)7iushed with two seta of [ili^iigh^ three iit each aet, pl»ced

f khars to sbtire, as shown in the drawings of Pinkua' flrat ^Jatent.

me set bavtng right hand turnovers, simikr to tho^ of the boni-

<^ii plough, fur phmghing from the engine in the punt to the

KUehor in the other punt in the opposite canal, the other set

living left hand turnovers for the return movement. In con-

" nictiou the ploughs and plough-beama differ considerably from

n horse ploughs, or from those of Mr. "Williams' (Baydon.

ptnita), Hallcett's, and subsequent examples of a similar kind ;

t in principle they may be said to be alike ; and when in ac-

1 they perhaps more resemble Fisken's, owing to the beams

% both terminating somewhat abruptly immediately before the

I^^oulter, tlian any of the other examples now in the field. The

beaina, together with the draught-bar and t^o suspension bars

of M'IfAe's ploughs, ubviously involve the principle of a ' parallel

motion,' as it was sometimes termed, to which the drawing does

itot do justice. Long prior to the date of his patent, the prin-

•iQplB of a parallel movement was discussed amongst practical

K&rmera who had received the necessary education to do so, such

■ m was taught at Edinburgh, Aberdeen, &c, where hundreds of
BSeotch farmere were annually tlius quiiliJied; and looking at

■ Vliae's drawing, wa are led to the cunclusiou that he ctintem-
^ojated the solution of this problem; but if so, he has evidently
Utiled. Into the mechanical details of such a problem it would
H» fonugn to the object of our present series of papers to enter,
Hb its solution has not yet been reduced to practice. Coleman
Bsd Sous, it is true, showed sometbLng of the kind at Chelmsford,
Bte 185S; but it was defective in several points.

■ . " It i« hut justice to M'Rae and his patent agent to observe
mliat, at the date of his patent, drawings were not made with tht;
FniDe accuracy a^ under the present statute, and his drawing ap-
P^vara rather to illustrate principle than the details of mechanism,
^n tiiat it would be highly uncharitable, if we are right in this
ILJiypotheBia, to examine it in any other tight, more especially as
■ihe invention or principles thus illustrated were immediately
ftrsduced to practice, as already stated.

B " According' to the drawing, thaietire, the dtau^ht-bar and

ENULSEEUISt; FACTS. LDjv. IX,

a wliua in action would be rigid, thtis fanning a, leverage o£
V thu eecoud kind ; the fulcmni, when the pluugh is lowered into.
I BL-tion at the one hettdland, or taken out of the ground at tin
I- u^iposite end oi the field, being the draft-pin of tbe copse by which
8 hauled when ploughing. Six vertical bara are bolted to the
I earriftge-frame, tliree towards each end, each bar being directly
')ove the body or frame of its own plough. These vertical bara
a for the lowering and elevating apparatus, which consists of
s vertical suapenaion-bars, working each in two guides, the
lower end being fixed to the frame of the plough, apparently a
little behind the centre of ^vity, and actuated at the upper end,
which passes through a slot, by a lever. Near tlie one side, and
towards the top of the upright bars, are seen the pins, upoa
which the levers work. Below the frame of the carriage are four
small pulleys for guiding the draught-rope or chain, and keeping
it from getting entangled with the ploughs j and upon the car-
riage above is shown a hand-rail, for thu aocontmodatiou of the
ploughman.

" The canals in Demerara, we may observe, ' rim parallel to
each other, and at a distance of from two hundred and forty to
three hundred and sixty feet apart/ quoting from M'Rae's spe-
cification.
I "The improvements made in M'Bae's steam, ploiigli, already
I referred to, are chiefly these. Instead of four carriage wheels, as
I previously adopted by Pratt and Pinkus, and subsequently by
[ Fiaken, vist., two furrow-wheela and two land-wheels, two main
[ central wheels are substituted, as subsequently adopted by Fowler
1 and Grig, one on the furrow and the other on the land between
r the two sets of ploughs, while two smaller Wheels are placed one
t at each end of the carriage-frame, now lengthened beyond tlie
ploughs, so Ds to enable the implement to cross the open ditches
between the canals, used for bottom irrigation in dry weather
I and surface drainage in the rainy season. These alterations were
I essentially necessary to the successful working of the imple-
I ment in the low-lying plantations of British Guiana. The
P other improvements have reference chieSy to alterations in the
I |>lough-beamB and apparatus for lowering and raising the
Iplougha.
L " We have already fitpr""""'^ ° \..^. f.^\TAi<n ..s \\.» ■^■^n^aa

m

^^ TlpOI

llACBiNEKY.] U-BAE'S aTEAM PLODGH.

Upon which M'Eae'a steam plough ia conBtnicted i and it is but
just that we should hero observe that the opinions thus enter-
t^neil are not based merely upon a knowledge of mechanicB, but
olao upon it» succeasfid working near Glasgow, and alao of tlm
equally suucessful working of Halkett's ploughs, made on exactly
similar prinuiples, the one experiment corroborating the otlier,
thereby proving the soundness of the conclusion. Leonard
Wray, Esq., in his valuable work, ' The Practical Sugar
Planter,' published so far back as 1848, by Sraitlt, Elder and
ICa, 65 Coruhill, London, speaks in the highest terms of thc^
Ttriuraphs of steam ploughing in British Guiana, as the foUowinj;
quotation will show : —

" ' As the plough arrives at the extremity of the field the two
boats move on the required distance ; then tbe motiou of the
en^ne is reversed, and the plough returns, so that by this sim-
ple arrangement the ploughing of an estate is accomplished most
expeditiously. The Demerara planters deserve a very great deal
of commendation.'

'• We might quote other authorities from our West India

ilonies, but the above is sufficient. That M'Kae's steam plough

ipable of improvement wiU reaiUly be granted. Indeed,

Libia is the reason why we are determined to have it con.structed

V, and hauled by wire rojies.

An accouiit of the experiments with M'liae's steam plough

on tlie lands of Fossil, near Glai^ow,' aa referred to above, will

found in the ' Mark Lane Express,' April 27, and November

6, 1840, and ' Fai-mer'e Magazine,' for June, 1840, and also

the number for December of the same year, the former quoted

the Glasgow Herald and the latter from tbe Olaagoin

Courier. Both reports pronounce the experiments ' eminently

locessful,' the expression of approbation just quoted being from

le former paper (the Nemid). Temporary canals were formed

to test the working of the two punts, the one carrying tlie engine

and hauling- dram, and the other the anchor-pulley as well as

tliat of the implement. As might be expected near the eutet-

priaing city of Glasgow, a large concourse of the laudowuers and

^mers of the neighbourhood were present at the trial, u8 also

f«ngineer8, including the writer, who was in Glasgow at the time.

hjghest praise was justly bustowt.'d upon Mj'. M'liiie and the

ESGINEEKINU FACTS, [Dn"

^B AM

^B Htssrs. F. Edington and Sous by all who wen< qualified

^H noiuice an iinbiftsaed opinion on tlie subject"

^1 The meeting of the Koyal Agricultural Society for 1863 was

^H held st Worcester. The trials of moat of the implenieutB and

^H ste^n) engines were competitive prizes being awarded to many

^H succoesful makem Of the agricultura] or portable engines

^H have already treated under the section devoted to lucomotivee.

^H In the coai'se of a somewhat cursory and hasty examination

^H not see any decidedly nnw or nuvel implements. Perhaps the most

^H nriginal implement was that of a chtdT cuttur, exhibited by A. £.

^F (Jhilda, the invention of Messrs. Gittus and Leggett of Milden-

liall, Suffolk. The blades were straight and moveahle on thi

M'heel, in place of being fixed and curved, and had the proper

uiigle so as hi obtain a drawing cut given them by means of

I fixed eccentric, the inner extremities of the knives being an
ducted to a. strap, wliich, much on the principle of feathering
paddle wheels, gave the necessary and constant angle of cut.
This machine was of necessity complicated and expensive, and
wu can only regard it as an ingenious and novel substitute for
the curved knives ', but Vi'e are strongly disposed to think that
fiir simplicity, and cheapness, and perfection of cut, nothing
ever supersede the knife of a proper curve.

Another new thing — if we may so term it, for it is rather thi
application of a novelty than a novelty itself — is the greatly-
spread adaptation of Bruckshaw and ITnderhill's elevator to
» thrashers; an improvement effecting a great simplification of these
•till much- to-be- simplified piacbines. Its general principle may be
said to simply consist in the gi'ain being brought into imineiUat«
contact with the blades of a common fan; the grain is thus
cleaned and elevated by the conjoint action of the percussion,
centrifugal force, and the blast, generated by the revolution of
the blades. The bringing forward of this valuable arrangement
has directly and indirectly effected quite a revolation in tbraah-
iug machines; and we have probably not yet seen the last and
most forward shape in which this improvement may be carried
out. It is, perhaps, not generally known that this adaptatic
tlie common fan has been proposed nearly a century and a half
ago, aiid has been in extensive use for many years by our "
Heuioas neighbours accoaa tUe ehanvwV _

] lUYE'S STEAll I'LOliim.

ma

Comiug now to tLe trial oj' ateaui I'louglis, tUe reimrt of wliich

B extract frum the Prueiicat Merhanies' Joicmal : —

"The stewarda of this department were Sir Archilialil M.

alonald, Sir E/lwarU Kerrison, and Mr. Torr. who wen

Slated, during the trial of steam ploughs, by Mr. Aiiios, tlie

society's conBultiug engiueer, and by four eri(;ineBriDg and prsic-

tival juilges.

" Mr. Haves, of Stony Sttatfiird, seiit a .slutionary engine

windla^B. The peculiarity of his system was that no signalling

id required, the anchormen at the ends of the work stopping the

action of (he vrindlase at iileaeiiro hy iiieauB of cords laid along

the field for the purpose. This is qd adyantage in foggy weather,

or when working by raooulight, and lessens the chance i

breakage from inattention of the engine-driver. Tlie wiiidiiig

drums are driven by baud-wheels ; the engine strap being shifted

L&om one to the other as lequirert, and thuK no whcohvork has

Bto be put in or out of gear, and by the simple movement of a

mdle the pulling drum is instantly atopped, the rotation of

libe paying-out drum arn'sted by a steam-jireBBure break, and the

Bnotton of bott^ drums reversed, llie implement worked v

B^Hio of Mr. Fowler's cultivators; but unfortunately an accident

red which prevented the prosecution of the experiment.

" Mr. Smith, of Woolston, sent a three-tined cultivator, driven

\ double-cylinder 10 horse stationary engine. Mr. Smith

^aa much improved bis combined cultivator atid corn drill Tha

raming is now light, but very strong, balanced upon a pair of

P'vheeln, ao aa to be turned round with the utmost eAse, and'

K^gQided with accurate precision in a straight line. With this

1 implement nine rows are sown at onc« iu a beautiful Beed-

terumbled by the tines out of moist ground previoualy imtoucheil

\hy any tool whatever. The saving of labour in ploi^hing a

repeated harrowing, and of time in seeding wheat or barley, 1

proved of vaat advantage on elay lands.

" Mr. Steevens, of Hammersmith, was one of the competitons,
but the machinery was di^hled by an accident at the conimence-

" Messrs. Savory and Son, of Gloucester, hang a G ft. dni
kn^wn friction rollers around the boiler of a double cylinder 1
« engjjiti The cjiindeis ate placed transversely in front oC

ENGINEERING FACTS- [Div. IX.

tlie smoke-box, and tlie crank-ahaft, pfiMing alongside the boilw
and within the dram (wLicli is a cylindrical ahfll without
or spokes), carries pinions which gear with internal teeth o;
dnim, and also a screw or worm, which actuates one of ihe tra-
wheels when the engine is required to advance. The
drum, being large enough to carry 500 ft. length of rope
single layer of coils, hauls the implement by winding up the
rope that runs singly across the field, and a similar engint i
apposite headland pulls the plough again to that end of the
jouple of guide rollers traversing in front of thi
drum upon a revolving screw shaft, feed the Pipe on to thi
drum so r^ularly that no coil grinds against or overlaps another.
'"Wliile one engine is hauling the other is simply allowing its
drum to run free, hesides advancing n few ieet along the head-
land into position for the next furrow. The implement worked

s a Fowler's plougk

" Messrs, J, and F. Howard, of Bedford, with a doublo-eylin-
der 10-horse portable engine, a stationary windlasa with coiling
dniius, the rope Inid out around the plot, and the slack rope held
Tii) off the ground by a ' compensating pulley '.{which i
plishes this with a much less waste of power than is occasioned
by applying a break to the paying-out drum), worked their
lliree'tined cultivator, making capital work, full 7 inches deep nt
' e rate of about II acres in 10 bour& This firm has brought
out a steam plough of very novel construction. The balance

ciple is altogether dispensed with, excepting so far i
general equilibrium of the machine is concerned, so that the ten-
dency of the set of ploughs in the air to liit the other set out of
V avoidei Two sets of plough bodies upon two beam
flames are hinged to opposite ends of a three-wheeled carriage
feime, and the weight of each set' of ploughs is sustained by

I spring in a box. Bnt the action of the parts is i
justed that when a set of ploughs is at work, the spring exerts
but a slight upward pressure; when the ploughs are raised the
spring gains greater power, and, when they reach the highest
point, bears up the whole weight.

" Mr. Fowler, of Cornhill and Leeds, has improved upon his
Ijppamfns fi)r employing the commim portable engine. The ro
J aonisa the iwld ani \»tt'& aieii"S iwSK^*;^ \**Nt«isa,'»

Of.x. MAOtisrEBT.] COLEMAK-S STE.UI PLOUGH. )ft7

['iilley on the self travelling anchorage and tlie 'clip-drum,'
wbich hauls the rope, not by coiling, but by gripping it tightlj-
iu a groove funned of moveable and eelf-acting pinching pitsces.
The drum is hang beneath a carriage, wfaicb has eharp blade-
tlanges upon Its wheels (removed for travelling upon hanl roads),
'tutting into the ground and withstanding the side pnll of the
rt-pe, and the carriage advances at intervals along the headland,
taking the engine with it. Of course, a driving belt could not
lie employed to transmit the motion of the engine fiy-whee] to a
Ijand-whuel uiHin the carriage, which alters its distance and pos-
ture at every advance. A chain of hard-wood blocks, in V-shaped
grooves, answers admirably, and will probably wear estrenjely
well. Owing to the loss of a plug, and a disarrangement of the
pump, the engine made too many stoppages for time to be taken
into account in its working of the balance plough with ' digger '
breasts at about 9 in. depth. Bedsides this form of apparatus,
Mr. Fowler has also his clip-drum huiig underneath the boiler of
a self-propelling engine; and, again, an airangement for two en-
gines, one at each end of the furrow, but each with a cuilinj^
drum underneath its boiler, instead of a drum engirdling it, as
in Messrs, Savory's invention.

" The system of Messrs. Coleman is different from any other,
in having two implements alternately hauled in work towanl
the engiue on one headland, and then back again out of work
toward an anchored pulley on the opposite headland, the ropes
being coiled upon two drums hung nt one side of the engine.
The double- cyhnder 10-horae engine worked two 6 lined culti-
vators at a depth of 8 in.

" Mr, Collinaoii Hall, of Navestock, has superseded the use of
wire-rope in his apparatus by a chain of round steel bars and
short flat plates and rivets at the joints, the drum and the an-
chorage pnlley being seven or nine aided, instead of circular.
Very little wear appears upon the present chain, which has
worked over 400 acres, and the rivets can be replaced at a trit-
ling cost; but time will soon decide whether a chain that cannot
be carried with advantage over friction rollers may compete with
wire rope that both Messrs. Fowler and Messrs. Howaril hold
clear off the ground in order to effect a great economy of motive
pawer aa{l of costly wear by Mctwa OTi tloda and stoniM

^m

ESGISEERINO FACTS, [Biv.

Tilt) competitoR who had not been disabltd hy accident w
o work ill a field of hard old lea, when the time of moving
ut of »ne fl^ld with the apparatufi packed up for travelliiig, anil
Wtliig down in another field half a mile aWay was noteil with
Iw following ruBtlltB ; —

" Mr. Fowler was 55 niitititea moving with eight horses, and
inished hie two acres in 1 liourSl minutes; Me^r?. Howard
lOved in labour with eight horaea, and completed their two
crea in 1 hour 57^ minutes; Messrs. Savory moved in 26
biinutes without an; horses at alt, and finished their two a
J hour 40 minutes; Mr. Smith moved in one hour with eiglit
hordes, and finished his two acres in three hours and one minute.
The depth was ahout seven inches iu all these cases; the fuel
consumed differed consideruhly — Fowler's was 3 cwt. 1 qr. 2 lb,.

•Howard's 3 cwt, 1 qr. 19 lb., Savory's 6 cwt. 1 qr. 10 Ih., aad
Smith's 3 cwt, 3 qr. 21 lb.
\ " On a subsequent day the cultivators were tested on some
heavy, hardened land, and the result was in favour of Mr.
Fowler's mftcliinery. If in common turn-over plougbing ou tlie
light land Messrs. Howard and Mi'. Fiiwler made equally beauti-
ful work, — the perieytion of the Uudford raouldboaids ae-
^, complishing the most neat and efficient turning of the slice,
^^g — on the heavy ground Mr. Fowler's ' digging ' shares have far
^^ntrpassed the cultivators of Messrs. Howard and Mr. Smith.
H%i fact, no such wonderful work has ever been shown before ;
the immense slabs of indurated clay being riven up and thruwn,
not for several inches, but for several feet. It appears to be
established that the stationary engine and windlass do not Ml
much behind the moveable engine and anchorage in amount of
^L^ribrmance, provided the rope be well carried clear otf the
^^nound; and that the employment of one engine is most econo*
^^Sical and best adapted fur single farms, though (as proved hj
^^Hessrs. Fowler and Savory) two engines may he most advBnC»-
geous for working by contract, when frequent removals and much
travelling from field to field are necessarily encountered.

" Mr. Seaman's patented improvements in agricultural imple-
ments, to be used in the cultivation of tlie soil, deserved Dotio&
Thiign jinprcveuientB are partV^ w^f'^'^^^^* ^ "jUnigbs, cultivator^
liJid haiTuwa, and ooimist liiatty ui «. ^aa'iivix axvaa

Oen. Machinery.] SEAMAN^S STEAM PI.OUr.H. 4nfl

mode of applying leverage to tlie frame of a cuUivator, no lliat.
by presaiiig down a levef it causea all lliu tiues aud eliares In
rise equally from tlie ground ; and seetindly. to t!ie mode of
forming that port of a cultivator, known as the share legs, with
the view of obtaining liglitness with giwi fitreiigth. Instead of
making them of solid bara the inventor oaes two light bars put
togetlier, with email atnits and rivets, so that when lonking at
tlie front of the atalk i>r line there is a space between the two
bars, and on talcing a aide view of the same stalk the upper part
is in two parte, one lying behind the other, but meeting towards
the front when they are welded together. Various other im-
provenients in details have alao been invented Mr. Seaiuiin
has also invented a peuuliar method of eonstructing wheels
for ploughs, cultivators, or other wheeled impk-meiita; and he
lias improved the construction of Whipple trees for the purpose
of applying power to the draught of agricultural implements anil
machinery.

" The prizes for the boat application of steam power for the
cultivation of the soil have been thus awariled ; — Tho gold medal
to Mr. John Fowler; and the sum of ^50 has been divided,
f 30 to Mr. Fowler, and £20 to Messrs Savory. The prizes for
the best application of steam power which may he effectively and
safely adapted for ainall ocoapations have been thus distributed;
£25 to Mr. Fowler, £15 to Mr. Smith, and £10 to Messrs.
Howard. Tu Mr. Steevens a silver medal has been awanieii,
whilst Messrs. Colemao have received u commendation."

At the Smithfield Club meeting held at the New Agricul-
tural Hall, Islington, a very rich display of implements and en-
gines took place. The following is an extract from a report by
the ' Mechanics Magazine.'

"Anytliing like a detailed description of the implements ex-
hibited would at oiice exceed our space, and prove nninterestiiig.
Literally speaking, the visitor miglit walk through the building
east and wejit, north and south, without discovering anything
very new, Perhajw tho most remarkable feature of the Exhibi-
tion lies in the self-pcopelling engines. In the International
>jthibition of 1851 there was not one traction engine ; and it ia
not perhaps Haying t^io much, to state that a general belief ex-
inlad that uuiut could Le coutriveit to auawer any commercial

ENGINEERING FACTS. [Dn-. IX,

purpose. All that U changail now ; and, Ixitli in Jinglaml nm
the colonies, road locomotives, day by day, act a miii« promi
nent part Our readers will doubtless recollect what an im
porlAnt class tbey formed at Kensington last year, and some pn
greaa bas been made aince. Mnkera of this description of steam
Uiachinery ilnily become more eiit«rpTiaing, and the dimension!

'nf three or tour of those shown at Islington, would have put thi
niilway locomotives of twenty years ago to the blush. Mesant.
Aveling and P<irter, Garrett, Clayton and Sbuttleworth, Fowler,
and Howard are exhibitors in this ckss, The workmanship of
their engines is generally speaking good, although individual
rnngements are not yet all that they should be. In the fii^
rank we must place an 6~horse engine, by Messrs. Aveling and
Porter, which appears to us to meet almost every possible

'4}nirement in the most efficient manner. Perhaps there is not at
present a tirm in e^tence which has had so much practical ex-
perience in the road locomotive. Although tbeir engines are,
comparatively speaking, a thing of yesterday, Messrs. Aveling
ftiid Porter hare completed altogelltei ninety-SBTeii engines of
the kind, ninety-six of which are in use. The engine exhibited
is of S-horse power, according to the method of calculation
adopted by the Eoyal Agricultural Society, having a 9 in. i^lin-
der by 12 in, stnjke. The gross weight fidl, is alwut 9'5 tons.
The general arrangements are too well understood to need descrip-
tion ; and the only novelties embraced in the present engine are
a simple modification for obtaining two speeds, and an improved
method of taking up the slack of the cliain. Close behind the
fly-wheel shaft a second is placed, carrying two spur wheels of
different diameters, which ate put in motion by pinions on thi
fly-wheel shaft. Either of these wjieels can be placed in geai
by simple means, according as the fast or slow speed is required
the other, of course, being thrown out for the time being. This
spur-wheel shaft is supported in brasses, which can be moved up
and down as occasion requires in curved brackets bolted to tlie
boiler, These brasses rest on iron packing pieces of varioua
thicknesses. When the chain becomes too slack by wear, it is
only nRccssary to raise the shaft and brasses in the curved plam-
hlocka, and replace e. lb™ ij'ifiVing ^ieee by one a little
cer, to take up th« aVasi. ut t\ia c'lwio. Tufe'wViiK.-u

r. HAcniSEST.] AVELINf.'S TRACTION MACHINF;.

Ibenl is kept ti^ht by saJtable eet screws, and snswers its purpose
'u the most efficient manner: it being intposaible, with the most
moderate amount of care, to put t)je second sliiift out of piirallel-
1^ ism with ttie first. The chain is made with solid block hnks 2
^Hb. wide, each finished in the shaping machine. Thus, a large
^^Kariug surface is provided, and wear is reduced to b. minimum.
^^ft may not be out of place to state tlint oue of these engijies, of
f^^ somewhat larger size, has travelled over 6,000 miles of country
roads, and is still a, very efiicieut macliiiic, having on one occa-
sion drawn 26'5 tons, in ciddition to its own weight, up an in-
cline of 1 in 12, 602 yards long, a performance almost unique.

" Mf^ssrs. Garrett and Son show a very neat single cylinder
8-hor«e self-propeller, embodying Mr. Aveling's patents. The
cylinder is placed in the smoke-box juat beneath the chimney.
~ 'fl engine is without the doubJe speed gearing. The driving
'a are 3 ft. 6 ia high, and very wide on the face. It is the
y road locomotive in the Eshilrition provided with spriiiga, if
'a-Tubber blocks, fitted in a very simple and ingenious axle-
Sus, deserve the uome. It is strange that engiueere should wil-
fully "shut their eyes to the advanti^es to be derived from the
interposition of a flexible mediuin bytween the dead weight and
i carrying wheels. It is in voiu to urge that, at slow speeds,
■■pedients of the kind are unnecessary, We never could un-
tatand why speed should be kept down to the same rate with
B unloaded as with a loaded engine. One of the best traction
ver met with, could draw 30 tons comfortably on a
till rond at 2^ miles per hour, and run light, at from 7 to 8
~ s with the greatest ease, thanks to the long easy springs so
juversally eschewed That they fonii an item of exjiense at first,
s admit; but the saving which they efl'i^ct in the subsequent out-
f for repairs far exceeds their firat cost. Messrs. Garrett also
Ebow a well arranged double cylinder portable 12 hnrae engine ;
II drill; a very good finishing thrashing machine,
with a single fan on the drum, shaft ; and several other articles,
the workmanship of which is quite good enough to maintain the
well-earned reputation of the firm.

" Clayton and Shuttleworth exhibit a traction engine, intended

t Egypt; the cylinders, 8'6 in. diameter, by 14 in. stroke, are

It the smoke-box just bcnuath the chimnev ', the driving

F.SGINEEEING FACTS,

[Dl/- !

r wliuels, oewly 7 ft. high, have cast-iron CBUular lims and wrought-
iron flpokes. The gent-Tiil arraiigcmenta ut' the machine a
^loi], aoil the workmanship excellent. T)iq ilriving gaar ie «
vory iieculinr, that, without drawings, it would be impossible t
give an act^tii'ate idea of it. SiifHw it to say, that the dnviiig
whuels each revolve looae oa the main axle, which ia immoveable
Just in the rear of the boiler, and al> a convenient height abovB
the fire-door, nuia a transverse shaft, uarrjing a differential eyetent
of gearing at the ends. This sliaft is driven by a pitch chain
from the eronk axle. Inside eacli driving wheel ia bolted a larg)
spnr wh<;c], put in motion by the transvtrHe shaft and differentia
I whi-'dla. The whole aS'air looks compllcitted, but is really very
I simple. T!ie effect produced is, that bo long as the reaistftnce ia
I the same to both lirivera, they will both be ppipelled with e
I velocity. li, however, the engine ia in the act of turning i
I corner, the inside wheel will simply remain at rest, or nearly sc^
I because the action of the steering gear places an obstacle in tl
P way of its progress ; the outside wheel will then ailvanoQ at i
BjiiNid aa much greater than its nunual vttlncibj, as that of till
iii.'ide wheel is leas. Thus, if one wheel were blocked, the ctbet
wheel would proceed ut a double velocity, the engine shaft 8l
making only thti same number of revolutions ; and this actioi^ s
80 perfect, that the steering is effoeteil with the greatest p
ua^ie. The whole arrangement is extremely ingenious, and t
ing well carried out with cast-steel pinions, &c, should prori
very durable. The steering is effected by an endless screw and
pitch chain ; the principle involved being none of the best, i
asmuch ua the screw offers a nearly rigid point d'appiti to any
force inipresaod on either fore wheel by obstractions on tl
and the ohanoes of stripping the teeth of the worm wheel s«
materially increased in consequence. While speaking of the fore
carriage and its connections, we may remark that no universal
joint arrangement is provided to permit either end nf the axle t
rise or fall independently of the eiigiii& This may seem trUling;
but it is on such trifles that the stiecess of the r>>ad locomotive
depunds. It ia folly to attom]jt to compel an engine to prooeett
(jver iiTegular ground on four rigid points of support A awlvd
joint in front obviates tbe difficviAt^ li^ reducing their number ti

^;i-\. MAcnrSEfiv.] FOWLEK'8 STEAM PLOUGH. 413

tlii: opemtion of steering is greatly facililateij. Meesu. Claytuu
ami Shuttlenurth also esiiibil, a double cylinder stationaiy Bngine,
fitted with expansion gear; a threeLiug machine; portable en-
f^inee, &c., of excellent workmanship and good design.

"Messrs. John Fowler and Co.'s stand presents little with
which the public are not perfectly familiar, save a rather coarsely
got-up traction engine, intended to carry an midemeath clip drum.
The driving gear is cnmpletely boxed up within a lieavy plale-
irou inclined trunk, canying the outside bertrings of the ahaflH,
su that it ia not very easy to determine what it is Uka The
steering gear is in one Bense extremely neat and compact, yet as
nunieiJianiGal and defective in principle as it well can be. A
large hand wheel on the foot plate, far removed from any bearing,
jiuta an endless screw in motion, throngh the medinm of some
gearing and an inclined shaft about 18 ft long. The endless
screw takes into a very smalt, qaadrantal, toothed arc on the fore
uarriage. This ceilaiDly does not look like good engineering.
The foot plate of a traction engine is generally far too small to
render it advisable that the steereman shiitdd discharge his duties
there. So long as n locomotive is intended merely for ploughing,
the arrangement may be tolerated, because the engine-driver can
guide the engine forward for the few yards required at a time.
The machine in question, is, however, set forth as a traction
i-ngine to which the winding dran) mci!/ be attaohed, if deemed
desirable; and such being the case, the steering wheel has no
business on the foot phite. An engine and windlass, similar to
that shown last year at Kensington ; a set of ploughs, cultivators,
&a., are highly creiiitable to the makers, and api>otired to mett
with thorough appreciation fiimi the pubhc

" Messrs. Howard exhibit a set of their patent steam-cultivating
apparatus, inuluding, of course, the inevitable 10-horse self-pro-
peller, by Clayton and Shuttleworth, and very similar in eveiy
respect, save the absence of dilforential gear, to the one showu
by that firm and already described. The workmanship of all
these articles is above the average. The merits of the system are
too well known to require comment.

" Messrs. Homaby and Son exhibit a very highly finished
aible cylinder pirtable 10-hurse engine, suitable for ploughing or
tr purposes, The cylinders are placed in a steam chest over tlia

r
I

I

ESGINEEKINQ FACTS. [Div. IS,

fire-liax. The propriety of using Itingituriinal wrougLt-iron si
rods from the cylinder covers to the crank shaft brackets, is trn
than doubtful The boiler must expand fat more than they «
removed as tboj are from any direct source of heat ; henc^ ^
tremendoua strain must be exerted oq the cast-iron brackets, which
appear to be quite slroug enongh in themselves to support an;
legitimate strain to which tbey may be exposed, without the aid
of auch questionable expedients. We notiiMid a very ingenious
and carefully got up reaping machine, in the same sbanil, whiol
delivers the corn from an inclined table, by means of a potent
arrangement of eudlexs chains, provided with fingers, whicli sffei
off the cut corn and place it by the side of the machine. Measra
Homaby alao exhibit an excellent thrashing machine, ploughs,
and many other articles,

"Messrs. Tultfo^J and Son show a lO-borse power patent
* housed ' engine, got up as usual with great care, an Ap]>ol(i
centrifugal pump, saw-bench, &c., which call for no particii'
remarJc,

" Messra Barrowes and Carmiuhael exhibit an 8-faorse ]k>i
table engine, one of the best of its kind, aa lar as neatness, m
plioity, ami good workmanship are concerned, that we have ev
seen. The cylinder can be removed from the boiler with tl
greatest ease ; all the bolts being accessible without I'eiiniving tl
lagging. The crank is slatted out from the slab. The (
head is peculiarly elegant in its crinstraction. The position oi
the cylinder on the centre of the fire-box shell is objectionably
bowever, as it entails a v^ high crauk-shaft. The engina it
provided with steel volute carrying- springs — an orrangemetil
which we tiAist will soon become more general.

"Mr, r. H, Wenhamexhibits the most remarkable engine within
the walls of the Agricultural HaU. This little machine, weighing
barely 2^ tons, and scarcely larger than an ordinary S^ho
portable, has indicated full 16-horse power. Tt is provided with
a high and low pressure cylinder, placed one at each side of Iha
chimney, on the haunches of the smoke-box. The smaller t"
the two is e in. in diameter, the larger 8g ia ; the stroke of both
being the same, 12 in. The cranks are placed at an angle of Sff

: ; stpam is led ditecV twTQ tW boUer to the small cylindar,

exhaust steam fiom vXtiiiV \e cawNc-jvA 'wi a. ■wK^^K&KMflja in

Ofs. M*chixert.] fOLUUSON HALL'S STEAM I'LOL'IJII. JIS

Ilia arooke-bos, tlie tubes of whidt ure coinuiilotit with llie biiili-r
lilies, 80 that both may be swept out at one operation. Tlie
•ileam dried and increaBed in volnme, by a temporary sojourn
liere, is tlien led into the lai^e cylinder, from ivliicli it fiually
escapes into the chimney. All the airangemunt)! are simple and
scientific, and we can very well credit the statement of the pH-
teutee, tbat he haa ohtained 16-horse power with about 32 lbs.
of coal per hour. Indeed, indicator diagrams, with wiiich we
have beeu favoured, leave nu room for doubt as to the actual
powers of a machine, which well deserves the favom' of aU em-
ploying portable engines. The email woight for a given powi-r
IS in itself no Blight advantage in a hilly or difficult countrj-,

" Mr. CoUinson Hall exlitbita a model of his ploughing appa-
ratus; aome illustrative drawings; and a steel link rope, eon-
etracted on his principle, which has ploughed over 600 acres of
stiff land and looks none the worse. Mr, UaU eschews the wire
rope, preferring one made of steel rods each about 18 in. long and
half an inch iu dianietn', jointed to the next by two small, Hat,
steel links. The windlass employed is polygonal, and thus slip-
ping is altogether avoided without any peculiar meclianical expe-
dients. Mr. Hall's drawings illustrate a system of working by
which the engine (or engines) rests stationary outside the field
to be ploughed, two anchors being employed, between which tlio
implement travels. The anchors are supported on small iron
wheuis, which proceed along the ht^adland automatically, on rails,
consisting simply of Sj-in, angle-iron bars of such a length that
they can be conveniently moved by one man. The flanges sup-
port the anchor wheels, and prevent that important member of
the system froni yielding to the strain of the rope. The angle
irons are retained in position by broad stakes driven into the
soil, against which they hear. The anchor man takes up the
bars as tbey are left behind, and, having previously driven the
stakes, puts thum down in position to receive the wheels as the
aiLchor odvanuea. We have, before now, spoken in terma of
praise of Mr. Hall's system, which is, we believe, really one of
the best yet developed. Its economy is not its least rcoommeii-
dation ; while its simplicity, and the ease with which the me-
chanism necessary ca]i be managed, and repairs effected, render
it eminently suitable for situations whore the aid of skilled

'ACTS. [ftiv, iT

ESr.lNEEHlNO FACTS. [fil

^1 liibour is "btiiiiU'd witli JifEcully. Mr. HaU'e apparntua ia<lLt-
^^B pbiyed ill the stand of Messrs. £. R. and F. Tiimvr, who «-
^V hibitagood 7-1iurse portable engine and tbraabing iQachine:
^^K niill a of variouH kinds; and Ager's patent digging inaciiine — au
^^K ingeiijfua implement, which it said tu perfoFm it« work vevy M-
^^H tisf'actorily.

^^H " Mtfxars. Wallis and Haslam exhibit a 4 ft. 6 in. cotnbiuect
^^f tliriuliiiig mochiitti, fitted with Coubou's spring hangers, and 1
\ hiiiiiineller resembling UnderhiU's elevator in its geneml details —

the fan is not uneii na an elevator,, however, its duties b«ing con-
fined tn till! Imiunielling of the grain, and tho supply of atab-
Iaidiar}- bhist for cleaning the cora In this ataod we noticed
very ingenious Btiiam pressei and plough combined, which ie wnll-
Bp<iken o£ This Arm has lal«ly purchased the patent for ~
ley's single wheel steerage for drills, &e., which we recomtneiiiL
to the attention of agriculturists.
" We had our attention called here to a well-iinialied mndel
of Wallia's patent system of raising and delivering goods owv
twd, three, or fnor hundred feet, over intervening ground or build-
ings, u'lthout interference with the trafBc beneath i tLereby saving
the whole of the expense uf trucking or l)ai'king, as mm in utie>
If gooils are taken from a sliip'a hold, or from a railway truck, [»>
the upper floor of a granary or mill, some power by applicatii
uf a atrap to a rigger, is required; but for loading out, th« ap-
]taratua is self-acting. The invention is partially carried oat, uul
may be seen at work at Wallis and Thomas's flr)ur ralUs, at Bbs-
ingstoke, where the intervening space traversed is 1 60 ft, oonii
prising a timber wharj; belonging to the loodon and
Western Railway Company, and a public footpatli."

We shall conclude this division by tlie following practioa] n-
marks on the value of " system," and on other points connecfoi
with the erection of machinery, and workshop dutiBB, 8elect44
" m the ' ^MHtiJ^c A

" Persons who have noticed how work is carried on in manj
' irge niachine-Blio'ps, caunot but wonder why it is that nff
JBtahlished system fl,ndioaW'ne\ft\mii\Q-w^te\ftE5wi«CT«A.Vi^Ui

W:

UaCI:

v.] ADVANTAGES OF SYSTEM.

il7

workmen. The advautages of such a plan are too olivinus to re-
quire any comment j and it is, as we have remarked, incredible
how many thisgs atv left to take cnre of tlieniselres, that ahould
have been regularly classified, and arranged with refereuce to tlie
demands of the work. Let us take, for instance, the item of
mandrels, as they are called here; or arbors, as they are Iwtter
known in some other parte. TJiese valuable, and indeed indis-
pensable aids to machine work in too many instances have no
more care or atteutiuu bestowed upon them than if they were
aemii-irou. They are often made of iron, instead of steel, and
are cut, backed, battered, and groimd in tbe centres, by careless
workmen, nntil tiiey are utterly uaelesa. A good niaadrul costs
too much money to be sabjected to such usage, and this is but a
small part of the evil ; for where such bad practices prevail there
are not likely to be good workmeu, and no siiup can create or
maintain a reputation where such careleasness is permitted. The
loss pecuniarily is to be considered also; for where there are no
regulations as to mandreis or other tools, any workman makes
one Bfi he rcqaiiea it, and throws it down on the fluor when he
[.JB done, from whence it is perhaps snatched the next moment ami
.y/sed for battering some other mandrel, into, or out of a puOey.
" Such foily and wastefulness as this must and should receive .
eereiest condemnation of every right-thinking person. System,
of mandrela, is not tbe only place where it
[hi be adopted with good results. Let us take the matter of
Tu too many workshops the only
for proper fittiiig work is placed on an old, illegible,
ptgwasy, shaky-jointed, smooth-ended, wooden two-foot rule ; which
' , JB about as useful fur measuring purposes as so many inches of a
broomstick. With this valuable aid, the old-fogy workman
gravely takes a pair of callipers, and turns up a shaft from it tu
the size of ' four inches.'

ARE SCRAPED SCRFACBS tNDIBPKNBADLK !

" In stating this question as broadly as we have done, we dis-

I nliiim at the outset any intention of dispensing utterly with

k toraped surfaces, or of erasing from the vocabularj' of mechanical

iZMtisa/itiea fJiia detail of the workabop. '£\i«^>it)\\H.>JM&«i

2d

ENGINEERING FACTS. (Drv. IX.

r mind whether much of the time and elaboration expended

on scmping iron Btirfacea might not, without injury to tbia work
iteeli^ he omitted. Tlie value of a poaitivel; correct face on a
I Talve seat or on the V-shaped riba of a slide lathe or pianer, is
I undoubtodlj' great when it ia well done, but when poorly ese-
I euted the utility of it is, to say the least, questionable. Wa
F make the unqualified assertion that not one man in twenty is
com|ietent to finish a truly scraped surface. Scraping iron down
to a perfect face ia an art by itself and comparatively little at-
tention, so to speak, has been given to the subject in this eonn-
try. The common method In use is to take an old file of any
kind (except round or sqnarw^, flatten its end out like a chisel,
I grind it up square on the stone, and then 'grub' away on the
' iron wherever the workman sees fit The chances are that pie-
■vioua experience has not fitted the operative for this branch of
his bufiineaa, and lie mistakes a shade on the iron tor a bearing,
and makes a depression still deeper by misapprehending the
' situation,' Of course the fallacy of attempting to make a true
face in this way is manifest to every one familiar with the sub-
I ject. It would have been (ar better to have saved the time wasted
I in such attempts and trust to good planing and attendance in
future to rectify inaccuracies.

" The better way to make a scraper is to fonn it like a Vene-
tian stiletto, or more iamiliurly, after the model of the section of
a beech nut; that ie, to have the blade triangular in aectjon, and
approaching concavity. With such an instrament, properly tem-
pered, ground, and sharpened, the finest work can he produced.
A flat-bced scraper is an abomination, and only fit to dig holes
or to rough out the work for the triangular scraper; it is apt to
1 make ' chatters ' iu the surface, and when these occur we may
I hid a long ferewell to any fine work without filing them oat — a
very pretty task to undertake after something like accuracy has
been attained. Most scraped surfaces are nothing hut a com-
bination of scratches, shining blotches, and untruth ; and while
they are a waste of time to execute, they add nothing to the
■uechanical value of the work. We may fairly question whether
1 of dp-seats up to 180 square inches of area, say 15 inches hy 13
Iflstabli!*"' fcen^&*«'l M acw.YUi^ "to wnaia Vis^^'^lvvo-shops in

^fffss^msm.

tool-marks on it run in one direction, and place the valve so that
similar marks in it cro»3 the seat at right angles, und to set tlie
valves running in this way ivithout further adjustment. The
results observed nre thiit in a few days the valve has made a seat
for itself that is far mote durable than if it had heen badly scraped.
"Wb do not go so far as some persons and assert that a. scraped
valve-seat is a positive injury, insomuch that the pores of the
iron are filled with an impalpable dust that works out to the de-
triment of the engine in future ; this theory is very finely drawn,
^^hough it may he partly sustained by facts. A finely-finished
^Btror-like surface on a valve-seat or lathe shears is indubitably
Hp great value, ami we must, in common justice, give credit to
^BgUah workmen for great skill in this particular; in general
^Key fer excel our own workmen.

^H " There is no reason whatever to interfere with the execution
^Ha finely-elaborated scraped surface in our own shops; hut our
^BkRervation convinces us that time spent in doing such work as
^Bjn have seen, might he better employed in some other way.

^ft EETINO WDEELB OH SBAFTa

^K** Wheels in macliinea are secured to shafts by difierent me-
^Bods, such as foi'cing them on, by keys, by sut« and washers,-
^Ed DQcasionally by riveting; keys are more generally employed
^■(ui any other device, being the surest way of preventing the
^Heel from turning, working off, or becoming loose, when the
^■SpectiTc key-ways are well made and the key properly fitted.
^Ve have heen requested by various correspondents, at different
^Bnee, to inform them where they could procure a work on key-
^■(^8, one which treated of the relative proportions for different
Hbea of wheels and shafts, and other general particulars which
Bte eiperienee of the author might suggest "We do not know
H| any, nor do we think such a work would be likely to meet
^Mth a ready sale; besides which it would not be at all easy to
Jg down rules, or laws, for definite instructions in a case where
Hb much depends upon practical knowledge. The principle of a
Jpiy is that of a wedge, and it secures the wheel mainly by that
Bferce; how far the taper of the key should extend, and what
Materia/ should be used for it, ate matters whitd ra.'ist, -iKwaEi

ENGINEERING FACTS- [Div

f

^^f wliolly upon knowledge acqtiireil by obsepvatioD. Iii Dearly all

^H cases steel Is prefflrablo for buisU keya ; but in some situations

^H Mft iroa IB better than the former, for the reasim that it affiliate^

^H or hugs, the shaft closer thnn a harder and hner-gi'aiiied metal

^H Tould. The aea-guing ateaiuere out of tliia port have laige keys

^B in their paddle akail centres, by which they ore held iu plaosL

^P It was at one time the praetioe to cast the eye or hole of tlie

centre octngonnl in ehape; each plane of the octagon being truly

filed to a bearing; the shafts also hod corresponding planes, and

when the keys were driven they were placed alternately with

reference to the head and point; one key being driven &om the

» right, the next one from the opposite side. In this way the
oentre was keyed up truly all round ; the keys were large dabs
of wrought iron, from 14 to 20 inclies long, by 4 inches wide,
and 1 ijich tliiiJc; the taper or 'draught' allowed on these was
not more than I'gth of an inch; in some cases not so much.
This plan of securing paddle-wheel centres has now been measoi^
ably done away with, as it was costly and not at all mliablc^ so
many keys bviiig ua^d that 'oue tnok thi^ strain off the other, and
some invariahly worked loose. The method now adopted is to
use one, or at most two, large and heavy keys. The centre is

Peered out in the foundiy, so that only one half of the circum-
ference of the shaft hole has to be hored ; this half is accnrately
bored to lit the turned boas on the shaft, and the keys are fitted
to ways cut in the uoreJ-ont part of the centre; when they are
driven, thurefoi-e, the bored part fits the shaft, and is forced into
the closest contact with it. This plan is now generally pursued
on all large steamers.
_ ~ " The hold of a key depends so much upon its fit and taper

^k that, aa we have remarked, individual experience must be the
^K guide to success ; but it is not amiss to assert that very littl»
^F taper ia necessary, and that beyond a certain amount the ten-
dency of it is to split the wheel and cause it to work ofE Tba
wheel should fit nicely, and then there will be still less strain
required to retain it in place. In all cases gib<heads to the keys
are a convenient meaus of drawing them out when such a course
is necessary. We Iwheve that car wheels are now preased on,
in the very heat praoUce, aii4 fti\s -siVW \«i fo\iwd a (fpod plan ia
moat eosea tor other work. Beasiiaa "bauni, d»i»»^v* "■» " "

I. Mai

] PIECE WORK— WOEKSHOPS.

421

there is always a bui'sting strain on tlie bub which ivwle
'Boken its endurance. Seats too deep and others too shallow
Lihe Bhaft and wheel ore to he avoided ; the latter soon works
f the comers where wheels are not well fitted, aud the furmer
unnecessary work and looks badly. In aU eases the key
I proportioned to the work or duty the machinery is to
and this proportion must be learned by observation, and
of the laws of common sense.

*' There is, it appears, a general and growing inclination, all

T the country, in favour of the system of ' piece work/ or of

|pwing each man to earn such wages b^ his skUl and ahilities

" ' " n to. In favour of the plan there is much to be said,

a in discouragement of it there would seem to he very little

ind for ohjection. In the first worksho]>s of the country the

1 of piece work ia now very generally adopted; and the

tt conducted and most prosperous establish men ts are invari-

j committed to this method of carrying on their liuainesa.

I proof of this assertion we may point to the Wheeler and

1 Sewing Sfaehine Manufactory, to the Waltham Watch

Qipany, and others we might name, all working by the piece,

a presume no oue will deny that if the piece work plan will

'n these places, there can be little doubt of its success in

tat branches of niauafacture, which do not require as much

e and constant oversight as those above mentioned. It has

■ted in condemnation of allowing operatives to work as

b as they chose, that the quality of the article produced was

1 inferior to that made by day work. This statement is

nsparently illogical, when we view the splendid work turned

t by tlio companies enumerated, and bear in mind the compe-

a they ore subjected to. In favour of piece work it may be

1 that the strongest incentives are laid before the workman to

e all the latent talent and ability he may possess. The

toriea in this cutuitry that produce a standard kind and

Bftlity of work, as pistols, sewing machines, &c, have special

' 1 for the accomplishment of their objects, which tools are

D ly the workmen; posuibly thej do i

I

423 ENGINEEKIHG FACTS. [Dvt. tX I

ag they might ; if a certain device was applied on Bome port they
wrnild do double duty. The man in chai'ge sees this, beuause it
is for bis interest to: it will increase his wages; the addition is
mftdo, sometimes at his own expense, and involving quite aa out-
lay: for the workman is satisfied to give t«n, or a hundred
dollara, where be knows that he will receive a thousand in
tiim. This is largely to the advantage of all parties — the ft
ceru and the artizana — and it is also a direct acquisition to thi
■world of art and science. If any pereon wishes to inspect tl ' '
machines — those that approach the nearest to human intelligent
— let hitn visit some of our best conducted manufacturing ei
blishments, and he will see what the system of doing work bj
the piece tends to encourage and develope,

" When a man is Iiired by the day, he gets his wages (if i
notoriously idle) even if be does not accomphsh nearly as much
as bis neighboui-; but when he lias a, stimulant lield out bafon
him to double his task, it induces him to strain every n
accomplish it We have heard it asserted that piece ■
tended to make men dissipated find demoralized, by tbe 1
wages they earned ; that they neglected their families and becami
idlers, &c, but this is a very weak argument against the syatem.
Piece work is not intended to force moral convictions opon a
workman's mind ; if he have not these principles instilled i
early youth, he is of little value as a crafteman, either by iS
piece or by the day. Piece work is an acknowledgment of a
man's right to earn all he can; while a certain amount of hire
weekly virtually limits his capacities to the sum alloweiL Men
work by the day pretty muuh as they chouse, whereas if they are
awarded contracts in themselves so to speak, they are more apt _
to execute them faithfully and quickly. Some brauohoa i '
manufooture do not admit of the introduction of such a system M
while many others, that are not so c<)nduoted, would be benefit©"
by its adoption.

" The lifo of a machine depends measurably upon two thi
'» construction, and. t^ie visa^w. U> -aVviv \.t \b snlijected;

III who

Maohikbbt,] CONSTHOCTIOH AND REPAIR.

a tiiacliiae is made, the greater credit will belong to those
who constructed it. But in sending awa}' machines &om the
workslinp as finished, mistakes and oversights are sumettmBa
committed, that redound injuriously to the makei's reputatio
■Theoretically, the mcchaniciil luinutia of the beat locomottTes
it a model which should be emulated, and copied into other
hanism all over the laud. To be expHcit — the
ily and accurately-fitted gibs and keys in the connecting rods
locomotive engines, the neat manner in which the brasses are
to their several places, the tight joints, the reamed holes,
steady pins, in addition to the security derived from screw
ilts, fur preventing parts from shifting out of line with each
should be more generally adopted as mechanical practice
t is. Of course, all machinery wiU wear out, sooner o
iJater. Every too! has its allotted period of service ; but the time
of its utility may be very raach lengthened by the manner in
Vhich it is put together. Cheap tools are not always cheap.
They may be sold at a low price, but they are continually break-
ing down, and require renewing so often that the outlay upon
ihem in a short time equals the value of a first-clasa article.
Tools to be cheap must be well made ; then they will laat for
yeaiB at a small expense for repair. Our steam fire engines have
in praised in England, on account of their superior finish, and
leral excellence of workmanship ; but those sent out were not
}y any means the finest we have, being only a sample ; the
Manhattan ' in particular having been in constant use nearly
years. We cite this fact as going to show the attention
iry where paid to good workmanship; and the important bear-
ig it haa upon the reputation of the. maker, and the perform-
icea of the machines themselves.

We have been sorry to remark, in some parts of the country,
general iuattention to the well-established mechanical laws
id rules (not scientific, but practical ones); as, for instance,
mtting a ^ bolt into an ^Jth hole; drilling holes too lai^e
diich were to be tapped; putting I'ough bolts into reamed
)les; using threads of too coarse pitch, and similar acts, pro-
lionally improper and irregular, which should not occur. Wo
Siake these remarks in no captious spirit, hut with an oamest
our mauuiacturera, all over the country, jvail

EFGTSEERINO FACTS. [Div,

lemselves of the skill and iniprovementa of others; believii!^
lat by si> doing tliey will ia the most direct manner serve tlitir
WD interests.

■niR ABUSE op Fiij:s.

" There fire hy fhr too many filsa wasted and mieuaed in ordi-
innry work, and the abuse h one that shonld be checked at o
To judge from the treatment aome peraoas bestow on tl
costly thiols, they are Eia common as pins and about as valuable.
A new file is used for fitting a Babbitt metal box to a sliaf^ or
a tile for brass-work is used alike on iiun and brass; and then
another mnst be procured when the workman desires to finuh
hrass again. And so the interchange goes on, mitil the conw-
3 is that the workman guilty of such carelessness has no
sle of any kind, fit for any purpose in his drawer. Hard sted
dilfereuca to a file-abnser either. Apparently then
a aome individuals who think that because a diamond will out
■-another diamond, so a file must bite another file; they pur
this theory and rasp away on the scale of cast-iron, or over
black places in forgiiigi^ with an utter disregard of their em-
ployers' time and money. A fifteen-inch flat bastard (ile cost*
from a dollar to a dollar and a half, but we have seen on
these tools placed Aoc* de combat in five minutes by the bltui-
dering stupidity, not to say criminality, of the person using it
If the individual had been obliged to buy it himself, it is honily
to he supposed that he would have treated it in such a roanuer,
It contributes in no wise to the reputation of any worknia;
be careless of tools that he uses but is not obliged to purchasft
and it would be much better for all parties if a little more coa-
Btderation was given to this mutter."

e of Files,

"load LooomotiTe, .

B* Spring-aealed Tjrea,

Africoltaml Show, triolt oi no

gtoee &t Wocceatar,
Ameriiut nod England, Comparatiir
LoDomotive Bxpenueq, .

■■" WorkiDg Exp

Fire Engines in,

, , Jaaton nod Sons, SleBto

-Itoe Engine, . . . '.
StJ-FricbonMBtciriolforJonntalB, 11
imlus, Hovaid's Steam Culti-
i
Apparatua for indicating Water

Xeiel in Boilers, .
Application of audre'a SU , .
An Scnkped Surfaces In(lispen»

impariBon of Breakii

Bifli Pntt'tured,

yiimn'fftt'f*'] Maneheater Boiler-
~ Biuiiiieers Beports,
Anunnre, Midland Steam Boilt
FBngineer'a Eeporta,
ll.'Veling'B Traction Eii^ne,
P.vard of PriEeB— Steam Plou|[hf
[ Prises — Steam Bngini
jt WoreeBter, .
bvud of PriieB — Steam
yginea, .

rl'iSfirs

nemer Steel Frocesa, .
re Gant Incline in India,
t, hot, Inf nence of, on Prodoc-
.m uid quality of Iron,
rtereci Plates,

Lploaions. See RaprntB o
Manchester Boiler Atsociatioi
tad Midluid AasnniDce Co.

4 Boiler, Marine, Improveiiient,
' "-='^rB, Mode of Setting,

■ra, LoconiotiTe, Lightneaa of,
rs, Steam Fire Enginea, . S

3 BoUers, Steel, data,
Boot-makingMaehine, . . 3

i Brasaea and Bearings, . . 1
Brass Boiler Tuhen, Bconom; of,

5 Breaking Strain of Different De-

Heri^ons of Iron, . . 3
! Breaking Strain Compariaon with
Frartored Area, "

Buttu

Calcnlaticn of Strains in lion, SI
Carbon, Slate of, in Combiiialion

with Iron, .... 21
Caron, M.. InrestigKtions Into the

Chemical Constitntioa of Steel, SI
Carnages, Lighting of, with Qns, 7/
'lost Iron Qirdeis, Permanent Set

of, under Presanre, . . 31
Oaat Iron, Proi:eeG of Beiluctton

from Ores 2t

Cast Iron, Breaking Straica of Dif-
ferent DescriptionB, . . 31
Cast Steel Bells, . . , 9
Oast Steel LocomotiTe Wheels and

Tjres, 2!

Cast Steel, Mayer'a, . . 2l

i Castings, Steel— Sudre's Method 21
Chemicnl Constitution of Steel—

M. Oaran ft

Cinder, Dxtniction of Inm from, 2
Cla^n and ShattleWDith— iW-

3 Coaf-minin^ »iaehine. '. '. 31
1 Collierj Linea, Mineral, Locomo-
tives for !'

r Colliery, Hartley Pit Engine Beam, :

1 CoUinwin Hall'a Steam flougb, i'.

Colemau's Steua Plon^, . ^ K

Comparison, Marine Bngine with

LmMimoUve,, . . . >

F

. . dElder-s.
Conpouod Murine Bnginea, Hum-

phnj wid TeDDoot's, 1

CampoDnd SlAtionaj}' tiDrizoiilAl
Bogituie, .... I
I OoDdnuatuio. Snrfsoe, ■ t

} CuiduotiDg Power of Brus and
InuiTuW
Oonatilnljiiii, Chemical, of Steel, S
OoiiHlriii'tloo uid Repair, . i

[ Con^U-uction, Engine, . . 1
OoDMruclian of Maeiuotrr, Bl-
tendea Cse of Steel in, . 3
' CoDgDinpCioD of Smoke in Laio-
I motivea, . . . . 1

Copper Tubes for Boilora,
( CwTodon of Boiler Platea,
,' Oaring Heated Jounuils, MsBoa of, 1
Cnrvea, Railway. Eaecta ou Balling

Biploeioii, Boiler Theories,
Kiiended Cae at Steel in the Con-

Btroctjon of Mauhinoij, . S

BjLtntatioD of Iron from Cioiler, 2

FitctoT of Sofetj in Iron and Steel

Description nf Turioos Metiillio and

SMoni-pBsked Piatoos, . 1

DMcriptioD of virioiu Iron and

Breaking Weights, . . 3
SeBcrifilioQ of various TDrhioaa, S
Designing of Turhines— formulie

Diatorbing Forces, Internal, in

Buton and Amog' Steam Fire Bn-

Eeononuc Advantages of Sj^tem,
ESeda of Bsilway Curves on floll-

isg Stock, ....
Blastio Limit of Iron,
Hastieitr of Iron, .
Kasticity of Timber,
Elder, Randolph and Co.'s Marine

132

Plow, Parallei Turbine Water

Wheels, .... a

Porcea, Inlemifl Disturbiog, in

PormuliB Dsed in the Dosigniug of
TurbiiiBB a;

Formulffi Used in Pmssia in Tell-
ing Bridges, ... 3:

FormoJie Used in Aecertnining the
Bretdting Weight of Timber, 3l

Pormulie Osod in the Investigation
of the Cause of the Hartlej Kt
Beam Practare, . . 85— lOll

Fowler's Steam Hough,

Fowler's Plonghing Bngir

Foumeyron'sTiirbinfl Water Wheel, 239

Practnred Aren, Compirison with

Original Area in listing Speoi-

Pnction, Anti-, Tutorial for Jour-

nats ia Kaehiaerj, , . i\
Frost, Influence of, oo Iron, , »
Furnace, Sudre's, for Melting

S4S

fts, Lighting of Railway Carriagea

I QMTett and Sona' Traction Bsgine, t.
267 1 Gauge of Hailwajs, - . . IJ
aSI Gaut, Bkore, Iodine in India, , 31
S17 Oelting, Coal Machine, . . a
'"'' Qirdera, Permanent set of Cast

Engine OonMruction,
Kngjnra, Beam Bngines, .
Bngines, Locomotive,
Bnginea, Marine,
Engines, Stationaij,
Engines, Traction,
Engine Trials at Worcester,
Bngland— Locomotive Expenses,
Enponflea, Working, of Staam Fir

Sn^nes in Amei'ica,
S^ierinents, Mr. Kirk^iiy!

Kj I Mu-uei-s, xurrnanent sei

Iron, under PrsBSUre,
'6 Gray and White Cast ~
_.t] , Gray and Sons' Steam
TT.GrOHth of Timber, .
133 1

170; Hawthorn's System of Working
102 1 Railways, "

ISO Heating of Jon . ., .__
173 I High and Luw Pressure S
1581 gineB, .

H^h Pressure Boi
226 Horiiontal Corapoi

\B(*, 'Eia«(l.,\BfillElltB

^^^^^r m 1

^^^^^E Vnf^\ Put 1

1" Howard's Steun Plough, , W8

Kircftldy'B, Mr., BiperimenU on

How&rd-B Steuii Cultivator, . il3

Stee! and Iron, ... 337

HniDphrey ftnd Teunaut'a Patent
Marine Englnoa, ... 177

Krupp's Steel, . . ■ . 284

I«e and Co. 'a Steam Fire Engins, 216

^^beline, "Bhara Gnat," in India, 251

Lighting of Baihraj CarriagOB with

^^■Mnsiice of Dot Blast oa Quality

Um, 240

^Kjud FrodnU! of Iron, . 2IIT

Link Motion and Slide Values, . 1«J

^Ksaenco of Fronton Iron, . 347

Loa<l, Safe, and nitimate strength

^^^tenittl DiBtnrbing Forces in Loco-

of Iron, relations between, . 311

' motivee 132

Load, Safe, of Iron, . . . S3S

ImBstigation into tba Causes of the
Hftrtlej Pit Beam Fracture, . 79

Locomotive Boilers, . . . 17

Locomotive Eipensea. comparison

between England and America,

Iron, Breaking Strain, compared

Ifift^lSS

with Fraotored area, . . 3*9

Locomotive Expenaes, MidlandRkil-

Iron, Bteatiug Straina of varioua

way 169

dBBcriptioQs of Wrought, . S23
Iron, Calculation of Strains on, 32tf

tocomotises. Internal DistnrWng
Foroea, 132

Iron, Cast, Permanent Set on Gir-

Locomotives, light. ... 137
Locomotives, Mneral for Oollieiy

dera under Pressure, . . S21

Iron. Cast, Breaking Strains of, 327

lines, 148

Iron, Eiperiinenla on, Mr. Kirk-

i^! artnwtion ixm CiodBr, '. 273

Iron, Haaticitj of, ... 317
ron. Elastic, liait of, . 331

Act of Parliament. . . 165

Locomotives, Speed and Weiglit

ron, Drav and White, . . 265
ran. Influence of Hot Blast oa

of, . . . . .* 123

Qualitt and Pro-luce, . 287
ron, Indusuce of Frost on, . 347

Locomotives, Wheela, laxje and
small, . . ... 125

Iron, Manufacture of Wrought, 275

LocomotivBB,Wheelsand Tyres, Cast

ron Melted, Teat of Qualil J, . 274
Iron, Ores <k. . ... 280

Steel, . . . . . 2B1

Locomotive Tyres, Adams' Patent,

Iron, Puddling, ... 276

Spring Seated, . . . !41

ron, Keiationa between Safe Load

aad Strength of. ... 314

Iron, SUte of Carbon in comhina-

Machine, Boot-making, . . 863

tionwith, . . . . SB3

Machine, Coal Mining, . . 891

^_Jroii, Strength of, under Cantinned

■Tst^, . .... 333

pair, 422

^^■nm Testing of Railway Bridges in

MachineiT, Ertendad application
ofSteef, .... 312

^KPnusia 336

^^bon Tnbes for Boil era, . 7

tical Hints, . . . . 41U

^KqdteI Turbine Waiar Wheel, 220—2*3

^■lonle'e-'oqaiTalent," lUB
^Hcumala, Heating of, means of eur-

tion. Engineers' Keports, . 17
"Manhattan" Steam Fire Bngino, 216

^B^ing, . . . . . 1S9
^Kniiinls, Anti-friction Material

Manufacture of Wrought Iron, . 276

^Kfi'c. 1^

^Bn>rt«n, Joseph, Fapet on Timber, 361

Marine Engines, . . . 17U
Mason's, Siand and Co. 'a Steam

^K«r''u.- yf^^^ "•> shasui. m

Fire Kn^piMs, , . . m .

Ibteri^, AuU-fdatlan, for Joor-

tak, 1

Uaycr'* CbM Steel, . . . 2

Melted Iron, Teat _^ Qiulitj and

KaWM of CiTsUU,

Midluid Bulwaj LocomotiTt

I Steam Binlei

■Co., Enijinaeni' Reporta,
I, T'ruck Louomoti

J nrw of Practoied S;
_ oi IiDii compareil witi
:tani oreu, .

iked Staam, Fiatoon, . . 1

liel Flow TurbineB, . 2

at, Adams', Spnuf Seated

Tjtres, '

I, AreliDg'B Traction Eneji
•niiOHt, Murioe EngJne, Hninplii
■nd TennanU'

Patei

itentLMliriDe EngJne,
ennanta'.
Marine Engine,

and El

Bandolph

neoB Wotfc,' Advantages of, . *
Period for FelUng Treea, . . 3
PeraianetitSetanCatjt Iron Girders. S
FiBbHiB, MetaJliiMind Sleam Packed,

tbeir relative eSciencj, ■ I
Piabm Siieeds of Steam Boginen,

77,1
PUtes, Boiler, Blialered, .
Power, CaudoDlJng of Braes and

Iron TnbBB, ....
Fower of Steam Enginea, . . I
PreaervttUoo of Timber, . . S
Prius, Awards of Bayal Agricul-

toral Show, WorcesWr, . . I
Priwa, Award! of, at Crygtal Palace,

Steam Fire Knginea . . 2
Pmctioal Hints in lie Mannfac-

ture of Machiiiei?, - 1

Prasjiire, penoBuent set of (Hrdere
" . under, 3'

BuiitT Eiplonon, . . . .

Properties of l^ber, . . ii
Prusaia, Formnla for Testing Iron

ihulwaj Gridgee, ... 3!

Qoality and Produce of Iron as

affected by Hut Blast, . St

Quality, Test of, in melted Iron, X

Bui way Bridges, Formula for Test-
ina, as

BaDdolpb and Elders Monne En-
gines, 17

Regnlations of lie Rood Locomotira
Art 16

Eelative EfficiBncy of the variouB
Steam and MeUJlio Packed Pia-

tiona between (he Safe Load
d Ultiuiate Streusth of Inn, 31
)rt. Engineers', Manchester

to;..

Beporta, Ennneen', Midland Boiler
Asaociation Co., . . . 1

Brault, tabulated, of Trials, Boyal
Agricultiual Show, . . \'i

Kesulte of Trials al Ciyatni Palace,
Steam Pire Engines, . . H

Raipe's Process M Puddlii " ' ~

Biieting Steam Boiler

Koberta Steam Pire E

Safe Load, relation between, and

DItimau Streagtb of Iron, . 311
Safe Load of Iron, . . . SX
Safety YaWea, . . . . B

Sapwood in Timber, . . . tSS
Scraped Surfaces, are tiey indis-
— usable! .... 418
an's St«am Plough, . . tO>
Seaauaiog of Timber, . 378

Betting itf Steam Boilers, . . St
Set Permanent of Cast Iron Qinlere, 121
Shand and Maaoa's Steain Fire Bd'

Sbow, Boyal Agricultural, Tria] of
£ngiue!i, .... ITS
lattlewaith aad Clayton's Trac-
tion Engine 4lt

Small andLarge Wheel Locomotives, ISS

^leed md Vclgiit of Locomotires, 12i
Speeds, PiEfon. of Enginea, 77, 101

" ■ ig-sealBi! Tjre«, AiiainH" Patent, H4

Statu of Curljan in cambiiiatia

StotioDBi^ Steua Endues,
Steftm Boiler AsaooialioD, Manches-
ter, Eneineer's Kepotts,
Steam Bailer Assmance Co.,

laiid. Gugiueers' Beports,
Bteaiu Buik'rs, Fire Engines,
Steam Engines, Locomotive,
Stem.1 Kngines, Jtiiriue, .

[u Fire Engine Boilers.

Trata of Qnality of Melted Iron, 2
letting Iron Hailwa; Bridge in

Proaaia, .... 81

Timber, Properties of, . . 3i

Tooth-Qhaplng Maehine, . . 3<

Traction Iliginen, . . . Ii
Triflla of Steam PluBgha.

Turbine Water Aheels, '. '.
Tubes, Brass and Imn Boiler, .
~ Setting Mmihiues, .

, Adams' Spring Seated, .

I^es, Steel, Loconiotive, ' '.

ast;

into, bj Mr. Caron, 304
ir, . . 283—293

... 284

I, Reipe's Process, S86

ents, Mr. Kirb&ldy's, 837

(d Oso of, . . 312

•e Tyres and Wheels, 291

Strains on Iron, Calculation of 3;

StniinJ', llie!Lking,of Wrought Iron, 3'
°'— ■' ''- -'-ing, compared with

Strength, DItiraate, of Iron, Kela-

tiona between Safe Load, kc i
Structures, Factor of Safety, . J
Saperheatine Steam, . 1

Surface Condenuation, . . 1
Sydenham Crystal Palaee, Tabu-
lated Trials of Steam Fire En-

Dltim

e Strength of Iron compared

llgUL Ol LUHlf^T, - . . iM

leel, Small and large, in Loco-

uotivea, . . . '. i:
leels and Tyres of Traction En-

jinas, It

lecls. Cast Steel, Loromolives, 21

leel Cutting Machine, . . 31

lirlpool Turbines, . . %

Wood Worliing Wacbinery, . 31

Wrought Iron, Mannfacture of, 21

Wrought Iron, Breaking Straini, 3t

Wronght Iron. Mr. Kirkaldj'B Ki-

penments on, ... 3!

\^