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Harvard College 
Library 




By Exchange 



SCIENCE CENTER LIBRARY 




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\pfc MORGAN. Sl^ 
Alliance, O 



SOCIETY OF ENGINEERS. 



ESTABLISHED MAY, 1854. 



TRANSACTIONS FOR 1874, 



EDITED BY 

PERRY P. NURSEY, Memb. Soc. Eng., Secretary. 



PLACE OF MEETING AND OFFICES: 

THE SOCIETY'S HALL, No. 6, WESTMINSTER CHAMBERS. 
VICTORIA STREET, WESTMINSTER. 



LONDON: 
E. & F. N. SPON, 48, CHARING CROSS. 

NEW YORK: 
446, BROOME STREET. 

1875. 



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M.\. ^ 






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PEEMIUMS FOR 1874 



At a Meeting of the Society, held on February 1st, 1875, 
Premiums of Books were awarded to : 

John Phillips, for his Paper " On the Forms and Con- 
struction of Channels for the Conveyance of Sewage." 

George G. Andr£, for his Paper " On the Ventilation of 
Coal Mines." 

S. Herbert Cox, for his Paper "On Recent Improve- 
" ments in Tin-dressing Machinery." 



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CONTENTS. 



PAGE 

Inaugural Address of thk President .. .. .. .. 1 

Recent Improvements in Tin-dressing Machinery. Bt S. Herbert 

Cox 11 

The Ventilation or Coal Mines. By George G. Andre 23 

Modern Systems of Generating Steam. By Newton J. Suckling 39 

Mechanical Puddling. By Perry F. Nursey 77 

The Action of Marine Worms and the Remedies applied in 
the Harbour of San Francisco, California. By John 
Blackbourn .. .. .. .. .. .. ' .. .. Ill 

Tramway Rolling Stock, and Steam in connection therewith. 

By Charles C. Cramp .. .. .. .. 119 

The Forms and Construction of Channels for the Conveyance 

of Sewage. By John Phillips .. .. .. .. .. 145 



r 



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SOCIETY OF ENGINEEES. 



ESTABLISHED MAT, 1854. 



COUNCIL AND OFFICERS FOR 1875. 
dwnmu 

President.— JOHN HENRY ADAMS. 

f VAUGHAN PENDRED. 
Vice-Presidents.— I THOMAS CARGILL. 

I ROBERT PAULSON SPICE. 
JOSEPH BERNAYS. , THOMAS G. IVESON. 

CLEMENT BARNARD. ' THOMAS PORTER. 

FREDERICK W. HARTLEY. I ARTHUR RIGG. 

CHARLES HORSLEY. ' WILLIAM ROEBUCK. 

Iftemkrs of Council, tz-af&cfo. 

Past President and Trustee.— HENRY PALFREY STEPHENSON. 

Past President and Trustee.— WILLIAM HENRY LE FEUVRE. 

Past President and Trustee.— BALDWIN LATHAM. 

Past President.— FREDERICK WILLIAM BRYANT. 

Past President.— WILLIAM ADAMS. 

Past President.— 3 kWZ CHURCH. 

Past President.— WILLIAM MACGEORGE. 

Hon. Secretary, Treasurer, and Trustee.— ALFRED WILLIAMS. 



Auditor.— JOHN WALKER. 

Secretary.— PERRY FAIRFAX NURSEY. 

Bankers.- Messes. BARNETTS, HOARES, HANBURYS, & LLOYD. 

Hon. Solicitors.- Messrs. WILKINS & BLYTH. 

PLACE OF MEETING AND OFFICES: 

THE SOCIETY'S HALL, 6, WESTMINSTER CHAMBERS, 
VICTORIA STREET, S.W. 



1875. 

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TRANSACTIONS, &c. 
■+*"- 

February 2nd, 1874. 

INAUGURAL ADDRESS. 

By WILLIAM MACGEORGE, President. 

It is now my privilege and duty to address a few words to you, 
Gentlemen, for the purpose of inaugurating this our twentieth 
anniversary. The Society of Engineers has fairly taken its 
place as one of the scientific institutions of England, and has 
experienced the various phases which societies, no less than 
individuals, have to pass through in their progress from infancy 
to maturity. It has now been founded nineteen years, and has 
not altogether escaped those vicissitudes which frequently 
accompany growth. I trust we may congratulate ourselves on 
our present condition and anticipate increasing power and use- 
fulness. It has been sometimes asked by engineers whom I 
have invited to join our Society, " What is the use of it ; and 
how can it benefit me?" Now such, though selfish question*, 
require an answer, and even on the lower ground of personal 
advantage and success in life I conceive the benefits to be 
great. It is in itself a diploma to be a member or an associate 
of a body whose papers, discussions, and general influence 
command the thoughtful attention of studious men whose 
operations tend to help those who are striving after a higher 
standard of scientific culture, and whose proceedings increase 
the knowledge of all whose noble ambition is the development 
of those laws which God has impressed upon matter for the 
increase of material wealth and the benefit of the human race. 
Besides these considerations, which may well gratify an en- 
lightened selfishness, there are others which deserve a passing 
notice; not leant among these is the material advantage of 
meeting our brother engineers, and so rubbing off antagonistic 
asperities and professional jealousies and acquiring from them 
a real practical knowledge of those branches of engineering 
in which we ourselves have not been specially engaged. All of 
us, occupied in active and some perhaps in harassing employ- 
ments, know the value of this practical knowledge as dis- 
tinguished from theoretical deductions. In the latter case our 
premises may not always be true and the facts be only assumed. 
After laboriously working out a plan which some professional 

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J 



2 INAUGURAL ADDRESS. 

emergency has called forth, which of us has not anxiously 
inquired whether any similar device has been previously tried, 
and with what practical results ? And after obtaining such 
knowledge, how thankfully have we not modified or perhaps 
altogether suppressed our own scheme ! This intercommuni- 
cation of ideas based on experience is the chief end of our 
meetings, and has always been an object of primary impor- 
tance ; and that such an end is capable of being served by them 
is surely an excellent reason why members of our profession, 
especially the younger ones, should also become members of 
our Society. » 

I have ventured to remark upon the main benefits to be 
derived from suclTan association as onrs, and need not take up 
much of your time by alluding to collateral ones, such as the 
pleasant social intercourse during summer inspection of en- 
gineering works, or our introduction, through mutual interests, 
to different sources of employment, and that higher professional 
status to which we may most legitimately aspire. 

But even though there may be many more advantages than 
those which have been enumerated, yet there are some things 
which should not be expected and cannot be obtained ; as, for 
example, making it a vehicle for advertisement or the advance- 
ment of our personal interests only. Nor have we any right to 
expect it to exercise any necromantic influence in promoting 
success in life. This can only be founded on knowledge, 
perseverance, studious application, and that admirable self- 
negation which forms the basis of every prosperous career. 
One most prominent feature of our Society is its catholicity, 
not confining itself to any one branch of engineering practice, 
but including in its membership representatives of all. The 
term "engineering" has no longer its former limited meaning, 
but includes a large variety of work. To do all creditably that 
an engineer is now called to accomplish, involves extensive 
acquaintance with abstract and physical science, and it is diffi- 
cult in ordinary practice to keep pace with the increasing 
advancement of knowledge and the rapid accumulation of 
practical experience. Indeed, it almost seems as if the demand 
for increased economy and production, due to the feverish 
activity of our times, is in advance of present engineering 
resources, and calls for novel and hap-hazard combinations. 
This gives an endless variety to the fields from which our ranks 
are recruited, and a wide range to the subjects of our papers 
and discussions. These papers, I think, should not be long 
essays or arguments, but short, precise, clear, and pointed in 
their style, practical in their character, and forming rather 
texts for discussion than having any pretence to exhausting 
their subject. All the hurry necessary to thinking and working 
during our ordinary avocations produces a strain upon the mind 

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INAUGURAL ADDRESS. 



which should be avoided in these evening meetings. It is most 
desirable that the mind should receive in a placid, easy manner 
the information so pleasantly brought under its notice, without 
the fatigue and labour attendant upon ordinary study. It is 
surprising how much may be learned by mere listening, and I 
trust we may be fortunate in having such papers as I have 
described during the ensuing session. During the last session 
we have had some excellent and useful papers which have elicited 
much practical knowledge not easily obtainable any other way. 

The first paper was read on the 3rd March by Mr. W. H. 
Fox, on the subject of " Continuous Railway Brakes," and it 
formed a sequel to one read by the same gentleman in the 
previous year, in which he noticed the kind of work a brake 
should be expected to perform ; and he described the hydraulic 
brake, showing also how the force necessary to stop a train 
varied with different conditions of weather and traffic. In the 
present paper the author gives the results of investigations, by 
which it appears that generally a train, travelling at the rate 
of 60 miles per hour, might be stopped within a distance of 
220 yards during ordinary weather by a retarding force equal 
to 18 per cent, of the train's weight. Mr. Fox next described 
the Westinghouse brake, in which the actuating pressure is 
obtained from compressed air ; the details of this arrangement 
were lucidly explained by the aid of carefully prepared 
diagrams. In testing this brake during its action on a train, 
it was found to be efficient and capable of fulfilling all the 
conditions prescribed as essential to the proper action of a con- 
tinuous brake. The author next described Chapin's electric 
brake, and by the aid of diagrams explained its construction. 
He showed how the electro-magnetic power was obtained and 
applied under each carriage as a retarding influence. Experi- 
mental researches as to the amount of retarding force wnich 
this novel and ingenious brake exercised proved it to be quite 
sufficient for the purpose intended. Mr. Fox was of opinion 
that this brake would ultimately prove a success, as it answered 
all the required conditions, but was still passing through 
experimental stages. 

The second paper, read on the 7th April, was by Mr. Henry 
Gore, " On Horse Railways and Tramways." This important 
subject, involving as it does the general vehicular traffic, the 
sanitary condition of the people in our large towns, and the 
amount of power consumed in the transit of merchandise, was 
ably treated by the author. The first part of the paper was 
historical, .and contained an interesting slcetch of road-making, 
from the Eoman period to modern times, when our great 
engineers, Telford and others, were employed in the develop- 
ment of the great highway arteries of the kingdom. The 
author then alluded to the early efforts of engineers to con- 



4. INAUGURAL A DDK ESS. 

struct tramways or trollyways in the mining districts in 1680, 
and described the wooden railways of the Tyne and Wear. 
The author then showed, by reference to documents in the 
Patent Office, that as early as 1803 the idea was started of 
using iron in the construction of street tramways, and a drawing 
was exhibited of the rail and mode of laying it. Mr. Gore then 
referred to several Acts of Parliament passed at the commence- 
ment of the present century, authorizing the construction of 
horse railways and tramways for general traffic, and mention 
was made of the roads between Gloucester and Cheltenham, 
and between Stratford-on-Avon and Moreton-in-the-Marsh. 
Some of the earlier street railways in the United States were 
then described, and also the attempts made by Mr. G. F. Train 
for the introduction of similar constructions into this country, 
with the causes of their failure. Mr. Gore then alluded to a 
tramway he had himself constructed at Valparaiso in 1863. 
Having finished his interesting historical sketch, the author 
described the principal features of various forms of construction 
adopted in the street tramways as recently laid down. This 
part of the paper was illustrated by a series of carefully pre- 
pared and well-executed diagrams, which clearly delineated all 
the important details of each type, including the use of con- 
crete, transverse timber sleepers, cast-iron block chairs, and 
continuous cast-iron girder rails. After describing the details 
of each system of construction, the author pointed out the more 
prominently objectionable features, especially condemning con- 
crete, from its cohesion being destroyed through vibration and 
the whole mass becoming broken up. Evils arising from the 
want of sufficient lateral support to maintain the gauge were 
then noticed, and the use of transverse sleepers strongly advo- 
cated as the best means of distributing the load and neutralizing 
the effects of vibration. He also pointed out the necessity of 
good workmanship in consolidating the foundations of the roads 
and in laying the sleepers aud rails, and recommended the use 
of a kind of tar or usphalte concrete as a setting fur the stone 
pavement and a packing for the timber sleepers. Mr. Gore 
deprecated the use of lime or cement concrete foundations for 
tramways, and concluded his interesting paper by urging the 
use of thoroughly desiccated timber to ensure durability and 
the avoidance, as paving or roadway, of all materials liaole to 
be converted into dust or mud. 

The next paper was read on 5th May by Mr. John Somer- 
ville, of Dublin, " On Charging and Drawing Gas Ketorts by 
Machinery ." The author referred to the necessity existing for 
machinery, firstly, on account of the exhausting and demoraliz- 
ing nature of a gas-stoker's employment ; and, secondly, as a 
safeguard agaiiist the peculiarly dangerous consequences of 
such strikes as we bad then so recently experienced. The first 

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INAUGURAL ADDRESS. 5 

attempt at mechanical stoking, invented by Clegg, consisted in 
feeding coal dust to the retort by an endless iron belt This 
scheme proved a failure, as well as Mr. Brunton's attempt in 
1840 to do the same thing. The first attempt at direct steam 
stoking was made by Mitchell, who used an apparatus running 
on rails in front of the retorts. Coal was fed into them at the 
top from waggons running on overhead ways, and the coke was 
pushed out at the opposite ends of the retorts. This arrange- 
ment never came into practical use. To Mr. Green, of the 
Preston Gasworks, belongs the credit of being the pioneer in 
mechanical stoking, for although the apparatus designed by 
him was not carried out in practice, it has served as the model 
from which all subsequent machines have been designed. The 
Best and Holden machine, next described by the author, was 
first tried at the Horseferry Works of the Chartered Gras Com- 
pany, and introduced to the works of the Alliance Gas Com- 
pany, Dublin, of which Mr. Somerville is engineer. It was 
introduced in 1867 in consequence of strikes. By this scheme 
the retorts could be charged and drawn at the rate of sixty per 
hour, or three times as fast as by manual labour. Mr. Holden 
has since introduced a new feature into this machine at the 
Beckton Gasworks, where it is worked by an endless rope and 
a ^stationary engine. The author next described Dunbar and 
Nicholson's machine, and stated that it was complicated in its 
construction, and though it had been tried in London, it had 
not been adopted. The author, after watching the action of 
Best and Holden's machine at his own works and noting its 
defects, designed another machine embodying improvements 
which suggested themselves. Two separate machines were 
used, one for drawing and another for charging, the retorts 
being served at both ends and the machines following up each 
other in their work. Mr. Somerville gave the results of work- 
ing these machines, which showed that the cost of carbonizing 
coal was 6<2. per ton by the machines, and Is. lji. by manual 
labour, this being the comparative cost according to Dublin 
rates. In London the difference would be greater in propor- 
tion as the cost of manual labour is greater. This paper was 
also well illustrated by diagrams, by the aid of *hich the 
different inventions were explained. 

The next paper was read before the Society on the 9th of 
June by Mr. S. A. Varley, "On Eailway Train Intercom- 
munication." The subject was introduced by a general history 
of the question, with special allusion to the early introduction 
of electrical systems as means of communication between 
passengers and guards. One of these systems, invented by 
Mr. W. H. Preece, had been adopted on the South- Western 
Bailway. Another, by Mr. C. V. Walker, had been fitted to 
trains on the South-Eastern Bailway, and the author's own 

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6 INAUGURAL ADDRESS. 

system had been applied to the royal train on the London and 
North- Western Railway. The cord system had, however, been 
adopted generally on this railway after several conferences of 
the committee of railway managers, and it had the provisional 
assent of the Board of Trade, but after four years' use it had 
failed altogether, for reasons into which the author entered 
very fully. The advantages of the electric systems for signal- 
ing in railway trains were next noticed. The author laid down 
six conditions which such signaling systems ought to fulfil. 
The three systems previously mentioned were next described 
in detail, with a critique upon the merits or defects of each. 
This excellent paper was illustrated by means of a signaling 
apparatus arranged on a model train of three carriages and 
two guard's vans. The electrical apparatus and couplings were 
full size. 

Our next paper was by Mr. Henry Davey, of Leeds. It was 
read on the 6th October, and the subject was " Recent Improve- 
ments in Pumping Engines for Mines." The author first 
indicated some of the main ends to be kept in view when 
designing steam machinery. Economy in its three aspects, 
namely, construction, maintenance, and consumption of fuel. 
With regard to economy of fuel, its importance was never more 
keenly felt than now, notwithstanding the great advance which 
had been made towards reducing its consumption. Our steam 
engines annually consumed 37,000,000 tons of coals, which at 
the then prices represented 27,000,000Z. sterling. In a period of 
twenty years the improvements effected in the Cornish engines 
had reduced the consumption of coal to one-fourth of that they 
formerly used, effecting a saving of 90,OQOZ. per annum on the 
old eoal bills, which would be about 140,OOOZ. at the present 
prices. Colliery engineers, on the other hand, made no attempt 
to reduce their consumption, as fuel was cheap with them ; but 
now as all that can be raised meets with a profitable sale for 
other purposes, economical steam engines become a desideratum 
for colliery owners as well as for others. Compound engines 
offer many and great advantages in this respect, especially 
contrasted with cases under the author's own notice, where 
from 12 lb. to 16 lb. of coal per horse per hour have been con- 
sumed for pumping water. A good compound engine would 
work with less than one-fourth of this quantity. The saving to 
be effected on 400-horse power of actual work by the substitu- 
tion of the compound system was stated to be at least 36 tons 
of coals in twenty-four hours, which, taken at the low figure 
of 5s. per ton at the pit's mouth, amounts to 2700/. per annum. 
Moreover, the old 400-horae power engine would weigh about 
90 to 100 tons, whereas a compound engine of new design 
weighs only about 55 tons. Mr. Davey next described his new 
system of compound engine and pumping machinery, which 

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INAUGURAL ADDRESS. 7 

were manufactured by Messrs. Hathorn, Davis, and Campbell, 
of Leeds, and which are successfully introduced into several 
large collieries. This novel machinery was illustrated by pho- 
tographs, working drawings and a large model, which made the 
arrangement of the details very evident. Like all compound 
engines, it consists of a small and large cylinder ; steam of a high 
pressure is allowed to expand to a moderate extent in the smaller 
cylinder, and is then admitted to the large cylinder, where its 
expansion is completed. The cylinders are horizontal, with 
action direct — the special peculiarity of the engine consists in 
its valve gear and the use of an auxiliary engine to work the 
valves. The admission of steam to the cylinder is perfectly go- 
verned by self-acting arrangements, which accurately regulate 
the quantity of steam to the load, however it may vary. 

The next paper in order of date, " On the Economical Uses 
for Blast Furnace Slag," was written by our secretary, Mr. Perry 
P. Nursey. The subject was treated in the first instance with 
reference to what had been done in utilizing slag by engineers 
compelled to get rid of a cumbrous product which occupied 
much land for its accommodation. Mr. Nursey referred to the 
use of blast furnace slag for making roads, and to its early use 
in continental ironworks as a moulding sand ; for this purpose 
it was granulated by being run direct into water and used for 
mould for pig-iron before being employed for finer castings. 
In this condition also it may be mixed with lime and pressed 
into bricks, or made into concrete or cement 81ag was also 
profitably used in making mortar, in the manufacture of glass, 
and as ballast on railways. Mr. Nursey stated that it had been 
used for similar purposes in England, and machinery for its 
treatment was now in operation. The author, by a series of 
diagrams, then described the machinery of Mr. C. Wood, of 
Middlesbrough, and of Messrs. Bodmer, of Hammersmith ; the 
former of these machines consisted of a horizontal revolving 
table, or else a vertical revolving drum. The table prepares 
the slag for concrete by a process of cooling as it leaves the 
furnace with a stream of water directed upon its surface. This 
disintegrates the slag, and it is* finally pushed off the table by 
scrapers into trucks placed beneath. Mr. Wood's other machine 
prepares granulated slag for making mortar, cement, bricks, 
and similar purposes ; melted slag runs from the furnace into 
a drum, through which a stream of water flows. The drum has 
screens placed inside, which strike against the slag and assist in 
its conversion into a fine sand delivered into trucks underneath. 
Messrs. Bodmer's machine acts upon a different principle, and 
consists of a pair of rolls, through which slag is run from the 
furnace on to a travelling band which delivers it where required. 
This sheet of slag, the author stated, was easily broken up to 
make concrete or reduced to the powder required to make 

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J 



8 INAUGURAL ADDRESS. 

bricks, cement, or mortar. Messrs. Bodmer also ran the slag into 
water for some purposes, but for bricks or cement it is pre- 
ferred to be dry for their manufacture. They have also special 
hydraulic-power machinery for making slag bricks, which Mr. 
Nursey described. Samples of the materials produced by both 
processes were shown, as also bricks, concrete, and cement 
made from them. The author showed that the results obtained 
in the manufacture of building materials from slag were most 
satisfactory, and justified the hope that the enormous heaps 
of this material now encumbering the iron districts will hence- 
forth become sources of profit to the proprietors and add to 
the resources of the builder by providing sound materials at a 
low cost 

The last paper of the session was by Mr. Charles Julian 
Light, " On a New Method of Setting Out the Slopes of Earth- 
work." The author described the ordinary process by successive 
approximations, and he proposed to substitute for this a direct 
and exact measurement on the surface of the ground where 
the inclination of the surface in cross section is nearly uniform 
and exceeds 1 in 100. Mr. Light submitted as a formula for 

determining the side width A «i— j-, where F is the half 

formation width, H the sectional height on centre line, D the 
difference of level on cross section at a distanc e A from the 
centre peg, preferably 100 feet* and M = V A a D 3 . The positive 
sign in the denominator applies to the lower side in cuttings 
and the upper in embankments, and the negative sign to the 
upper side in cuttings and the lower in embankments. The 
author explained some modifications in the formulae which are 
required at or about the balance line. Mr. Light concluded by 
describing the tables calculated to be used in connection with 
his formulae, and illustrated the mode of their application. 

All these papers were well discussed, and will form an in- 
teresting ana useful volume of ' Transactions. 1 During the 
summer months the members and associates made some visits 
to engineering works. In May we visited the works of the 
Albert Bridge, at Chelsea; the Thames Embankment, at the 
same place ; and the Wandsworth Bridge. In June our visit 
was to the Royal Small Arms Factory, at Enfield ; and in July 
we inspected the works of the East London Bailway in con- 
tinuance of their line from the Thames Tunnel at the Wapping 
part of the London Dock, under which it is taken by a tunnel 
in course of construction partly by cofferdam and partly by 
open cutting. These visits were made by a large number of 
our members and associates and personal friends. I trust that 
our inter-sessional visits will continue to be popular, and that 
they may prove to be more than mere holiday excursions. 

The subjects for interesting and instructive papers are 
numerous and very diversified, for now engineering embraces 



INAUGURAL ADDRESS. 9 

so many things that no catalogue can do justice to their 
endless variety. But most prominent at the present time may 
be mentioned the sewage of towns, with the complicated 
questions affecting the sanitary conditions of large centres of 
population and the comfort and convenience of the inhabitants 
of our ever-growing cities. Then there are bridge construction, 
railway engineering, steam navigation, and hydraulic machinery, 
now hardly out of its infancy, besides those tools and other 
labour-saving appliances now even mofe than ever necessary 
through the rapidly increasing cost of production. The supply 
of towns with water, gas, and perhaps some day with heat, are 
all matters upon which information is valuable ; and lastly, I 
may mention that perennial source of matter for thought and 
consideration— the thing of all others most universal and 
diverse in its applications, most essential to all modern com- 
forts, and without which the ages of darkness would soon return 
upon us — I mean the steam engine. It alone seems unchanged 
in principle, and yet in some details of construction ever new ; 
whether in peculiar necessities for space or arrangement or 
means for increasing the economical use of steam, either in its 
cylinder or the everlasting changes in its valves, there is always 
much that is new, and perhaps more of general interest than 
in any one machine or tool which may most nearly compare 
with it. 

With reference to marine engineering, with which I am pro- 
fessionally connected, I can only now allude to certain prominent 
facts which have come under my own observation. It is well 
known that the consumption of coals per indicated horse power 
has been reduced from about 12 lb. to somewhat less than 2 lb. 
This must be ascribed chiefly to the increased pressure of steam 
now used. In my own recollection the pressure of steam in 
steamship engines has increased from 5 lb. to 100 lb. and up- 
wards. The pressure now adopted ranges from 60 lb. to 70 lb. ; 
the former pressure being more generally used. In most cases 
these higher pressures are used in compound engines, with 
which steamships are now almost universally fitted. In some 
ships, where the expansion of high-pressure steam was com- 
pleted in a single cylinder, the engines have been replaced by 
compound engines with decided economical gain. But late 
improvements in steamship machinery have not been confined 
to the engines. Many important modifications of the propeller 
have resulted in considerably increasing the coefficient of ships. 

In many instances the consumption of fuel in proportion to 
work done by a steamship has been much less than in similar 
ships where the engines worked with a much higher economy 
per indicated horse power. The machinery used in the con- 
struction of modern marine engines and boilers is a most 
interesting subject, but into this and the many collateral ques- 
tions connected with marine engineering I cannot now enter, 



10 INAUGURAL ADDRESS. 

but I do trust we shall have an opportunity of discussing them 
during the year. 

Among those we have lost in the year that has gone, there is 
no more distinguished name than that of our honorary member, 
M. Eugfcne Flachat. This gentleman stood in the first rank 
among French engineers, and was one of the principal founders 
of their Society of Civil Engineers, seven times its president, and 
finally elected to the honourable position of honorary president 
for life. He was, perhaps, the sole French engineer whose career 
can be compared to those of our own country who have so fully 
impressed their energy upon all branches of modern industry, 
and the versatility of his talents was most remarkable. Me 
superintended the infancy of railways in France, and carried 
out the steam navigation of rivers. He introduced new methods 
from this country into French metallurgy, applied cast iron to 
bridge construction, and wrote numerous and most valuable 

Sapers for the important Society of which he was the most 
istinguished member; finally, he rebuilt the foundations of 
the Cathedral Tower at Bayeux, and assisted at the prolonged 
defence of Paris. Doubtless the hardships of that time tended 
to shorten his life, and he died on June 16, 1873, deeply 
lamented by all his friends and associates. 

During the past year twenty members and nine associates 
have joined us, our financial position is good, our revenues have 
become more certain, and the general interests of the Society 
more consolidated. This satisfactory state of affairs is due in a 
great measure to the Council for the time and labour they have 
bestowed on our affairs, but chiefly are we indebted to the 
untiring energy, ability, and skill shown by our late President, 
Mr. Church, in filling the responsible office of President There 
are also two names which will occur to every one of us, those 
of our Honorary Secretary and our Secretary, to whom our 
thanks are most particularly due, and these gentlemen really 
work harder than anyone else in their endeavours to promote our 
interests. 

1 now for the first time occupy this chair, and perhaps may 
not be able to devote so much time or bring so much ability to 
bear upon the affairs of our Society as our late president and 
other distinguished men have done, but to none of them will I 
yield in devotion to your interests and in endeavours to enlarge 
our influence. In these endeavours, which I trust may be 
successful, I shall count upon the hearty co-operation of my 
colleagues in the Council, and now invite the assistance of each 
individual member and associate. Yours is the principal gaiu, 
and without your help we shall never be able to raise our 
Society to the position which it is capable of occupying, nor to 
realize all the benefits to be obtained from membership in such 
a body. 

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( 11 ) 



March 2nd, 1874. 
WILLIAM MACGEORGE, President, in the Chaib, 

RECENT IMPROVEMENTS IN TIN-DRESSING 
MACHINERY. 

By S. Herbert Cox. 

The general subject of tin dressing having been fully treated 
in papers read before various professional societies, as well as 
in several scientific works, the author does not propose to re- 
discuss that question, but simply to direct attention to such 
machines as have been invented of late years in connection with 
the process. 

The general processes of tin dressing are as follows : The 
tin ore, on coming from the mine, is first ragged, or spalled, 
i. e. broken by hand to a size not exceeding that of a man's fist. 
If the end where this ore comes from be new ground, the head 
dresser, in order to form some idea of its quality, proceeds to 
van a small portion of it. This process consists in crushing 
some of the ore (a sample being very carefully selected of a fair 
average value), and then bruising the ore mixed with water on 
a shovel, until it is reduced to a fine slime. The shovel is 
immersed in water from time to time, and an undulating and 
circular motion given to it The light earthy particles are by 
this means carried over the edjje of the shovel, leaving the tin 
or other minerals of higher specific gravity. The specific gravity 
of tinstone or the peroxide of tin, which is the only ore of this 
metal found in marketable quantities, is about 6*5, and the 
minerals with which it is generally associated are mundic or 
iron pyrites, specific gravity 4*9; copper pyrites, specific 
gravity 4*25; and wolfram, or the tungstate of iron ana man- 
ganese, which has a specific gravity of about 7, or rather more 
than that of tinstone. 

It will be seen that by the process of vanning, tin ore can to 
a great extent be separated from the copper pyrites and mundic, 
whilst the wolfram will remain, and so in the ordinary course of 
tin dressing wolfram costs more than its market value to 
separate it from the tin. The separation, then, of tin from 
wolfram cannot be effected by the simple methods of utilizing 
the difference in specific gravities employed in separating it 
from its other impurities. It moreover resists the process of 

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12 RECENT IMPROVEMENTS IN TIN-DRESSING MACHINERY. 

roasting, to which a large proportion of the Cornish tin is sub- 
jected, in order to free it from su^hur or arsenic in the pyrites. 

The method of separation now employed is as follows : The 
ore after crushing is introduced into an open hearth furnace, 
mixed with soda ash in a proportion varying as the ore is more 
or less contaminated with wolfram, and the furnace is kept at a 
bright red heat for some hours, the mixture being stirred from 
time to time. The fused mass is then removed to a large pan, 
which is subsequently three-fourths filled with boiling water, and 
this is allowed to stand for about three hours. The supernatant 
liquor is then run off, and the process repeated in another pan, 
afid then in a third, the only difference being that in the last 
two the water is cold, and is put in first. The ore is now prac- 
tically free from its injurious ingredient, i. e. the tungstic acid 
has gone to the soda, forming tungstate of soda, which has been 
dissolved out by the water, and the iron and manganese can 
now be separated by their specific gravities. The solution of 
tungstate of soda is then pumped up to an evaporating pan, 
and evaporated slowly until it assumes a certain strength, when 
the tungstate of soda crystallizes out, and is ready for the 
market. The ore having been first spalled, is taken to the 
stamps. The old Cornish stamps consist of heavy rectangular 
blocks of cast iron, weighing about 5 cwt each, which are lifted 
alternately by means of cams fixed on a horizontal axle placed 
behind the lifters. There are from three to five head of stamps 
in a set, the number of sets or size of the battery of course 
depending upon the requirements of the mine. The height to 
which the stamp heads are raised is about 8 inches, and the 
speed about sixty blows per minute. There are several improve- 
ments proposed on this method, and that at present receiving 
most notice is the system of stamps patented by Mr. Sholl, to 
whom the author is indebted for much of his information con- 
cerning them. These stamps are illustrated in Fig. 1, and their 
principle is as follows : The set of stamps is fixed in a cast- 
iron frame, at the top of which is a three-throw crank, with a 
driving wheel at one end and a fly-wheel at the other. Sus- 
pended from each crank is a piston-rod and piston working in a 
cylinder, the whole being kept vertical by bush guides. The 
stamp heads are fixed by means of a shoe at the ends of .the 
cylinders. It is in the action of the piston working in the 
cylinders that the speciality of the machine consists. Mr. 
Husband, of the firm of Harvey and Co., Hayle, has patented 
an improvement upon Mr. Sholl's stamps, but it consists chiefly 
in a varied form, the principle being the same, viz. the varying 
air-cushion above and below the piston. 

Hitherto it has been impossible to drive stamps directly fron 

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RECENT IMPROVEMENTS IN TIN-DRESSING MACHINERY. 13 

a crank, because no arrangement existed by which the length of 
€he stroke could be varied, whilst the play of the heads must 
depend partly upon the quantity of stun underneath the heads, 
and partly upon the wear of the heads. These difficulties are 
now obviated by utilizing the expansive action of air. There 
are also several other methods proposed, such as using springs 
to give stroke, and another system of steam or compressed air 
cushions, but the author is not aware that any of these schemes 
are at work. In the pneumatic stamp the object is thus 
obtained : As the piston is driven down in the cylinders by the 
descent of the crank, it compresses the air beneath it to between 
four and five atmospheres, thus greatly increasing the mo- 
mentum of the stamp head at the end of the stroke, the same 
effect taking place in the return stroke. By this means it will 
be seen the length of the stroke is self-regulating, being, how- 
ever, always greater than the throw of the crank, and that if 
brought up sooner than usual by an exceptionally large piece 
of ore, or through careless feeding, the only effect is that the 
air is further compressed. The hammer is guided in and slides 
loosely through a guide, below which is a metal box, in which 
water is constantly supplied by a pipe issuing around the 
hammer cylinder in Sholrs arrangement, and around the stamp 
rod in Husband's, the cylinder in the latter case being above 
the coffer. The object is to prevent wear by washing the surface 
of the hammer cylinder, or rod, and cooling the stem, which 
naturally becomes heated by the repeated compression of air. 
The advantages of these stamps over the old ones are as follows : 
(1) A greater length of stroke is obtained, by which the weight 
of the heads may be reduced, these being about 3f cwt. against 
5 cwt. in the old ones. (2) A greater speed is obtained, the 
comparative speeds being 150 and 60 blows per minute. (3) 
The additional momentum produced by the compressed air, 
and the power by the same means of regulating the length of 
the stroke. 

The manner in which both the old stamps, and likewise the 

Sneumatic ones, are worked, is as follows : The ore is supplied 
own an inclined plane at the back, called a pass, down which a 
stream of water is constantly flowing, and which washes the ore, 
after being crushed by the falling stamp heads, through the 
grates or perforated iron plates in front and at the sides of 
the stamp frames, or coffers, into the drags. The size of 
the holes in the plates varies with the class of ore to be 
stamped, but they have usually about 38 holes to the square 
inch. These are punched, and the concave side turned towards 
the stamps. These grates shoulH last for about a fortnight 
in constant work, but at some mines there is a considerable 

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14 RECENT IMPROVEMENTS IN TIN-DRESSING MACHINERY. 

quantity of acid in the water, which corrodes the plates, and 
tney are then very soon rendered useless, twenty-four hours 
sometimes sufficing to spoil them. In such coses Copper plates 
are substituted. 

After stamping, the finely powdered ore, mixed with water, is 
run over a short incline into drags, or wooden troughs, about 
20 feet long, 12 inches wide, and 15 inches deep, with a fall of 
about 1 foot in the length. Here the first operation of sepa- 
rating begins, the best or heaviest tin settling at the head of 
the drags, the second quality and the finest taking the middle 
and tail respectively. The drags are open at the lower end, but 
as they fill are closed by means of pieces of wood called strips, 
which are slid down into grooves, thereby just keeping the 
overflow of the slimes on a level with the last deposition of tin, 
and not washing any that has been deposited away. 

The contents of the drags are divided into the head, middle, 
and tail, and these are put through one, two, or three circular 
buddies, or are taken direct to the square ones, as the quality 
of the ore may require. Circular buddies, seen in Fig. 2, are 
pits from 13 feet to 18 feet diameter, and about 2 feet deep at 
the circumference, the bottom being boarded and rising towards 
the centre about 1 foot In the centre is fixed a cast-iron 
hollow cone, through which the ore from the stamps is supplied 
by a wooden launder or trough. Boys place the stamped stuff 
at the head of the launder A, and a constant stream of water 
washes it down to the cone, through which it posses and thence 
spreads itself over the bottom of the buddle. Two wooden arms 
with loose boards and fringes B are attached by means of strings, 
by which the height of the fringes can be regulated as the 
buddle fills. These are turned by means of geared wheels, and 
the fringes trailing over the surface spread the ore evenly, 
which would otherwise run into ruts. A breadth of about 
9 inches of water is kept round the circumference of the buddle 
while the operation is going on, to prevent the escape of any 
ore through the holes by which the water escapes. When full 
these, like the drags, are divided into the head, middle, and 
tail — the head and middle being, according to circumstances, 
either rebuddled in circular buddies or are taken direct to two 
separate square ones. 

Another form of circular buddle used for the more finely 
divided stuff is in principle the same as the one last described, 
but, instead of being convex, is concave. The tinstuff is carried 
from the centre to the circumference by four small troughs, 
about 2 inches wide and 2£ inches deep, the slimes being 
carried away from the centre in a similar manner to that 
employed in the convex buddle. 

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RECENT IMPROVEMENTS IN TIN-DRESSING MACHINERY. 15 

It is evident that the action of the concave buddle is the 
reverse of that of the convex buddle, for whereas the action of 
the water in the convex one decreases as it reaches the 
periphery of the buddle, having of course a much larger surface 
to travel over ; in the concave it increases as the area is reversed. 
Hence the slimes or mud (for all available tin has by this time 
settled at or near the outside edge of the buddle) are removed 
from the buddle by the action of water alone, thus savins 
manual labour. This buddle was invented by Mr. Edward 
Borlase. His brother has' recently invented another circular 
buddle, which is being adopted to some extent in Cornwall. It 
consists of a large annular table which revolves on an axis 
vertical to the plane of the table. The table is set on an 
incline, and the stamped stuff is supplied at the highest point 
with a considerable flow of water. The revolving table retains 
the heaviest ore and carries it round to the bottom, where it 
is washed off into launders and thence conveyed to circular 
buddies. The slimes flow at once across the table to an opening 
in the centre, where they run off into launders to the slime pits 
or settling pools, where the heaviest portions settle and are 
again dressed. 

Square buddies are wooden boxes about 8 feet long, 3 feet 
wide, and about 2 feet 6 inches deep, having an inclination of 
about 2 feet in their length, and are sunk below the level of the 
tinhouse floor. The head is an inclined plane about 2 feet above 
the bottom of the buddle. The tinstuff is distributed evenly 
over the head by a boy who feeds the buddle ; guides of wood 
were formerly used to distribute the ore, but they are now seldom 
seen. Two boys attend each square buddle, one feeds and the 
other stands on a board placed across the buddle, and continually 
sweeps upward and across the tinstuff as it falls, thus keeping 
an even surface. At the lower end is a vertical row of holes, 
through which the surplus water flows, and, as in the circular 
buddies, about 9 inches of water is always kept between the tail- 
board and the work by plugging up one, two, or three of these 
holes. 

Another form of buddle, known as the propeller knife-buddle, 
illustrated at Fig. 3, has lately been introduced at the Kestron- 
quet Steam Tin works. It consists of a cylindrical frame of about 
6 feet diameter, and from 9 feet to 10 feet long, fixed on a hori- 
zontal axis. A series of knife blades or scrapers are arranged on 
the periphery, as shown, so as to take the form of a screw. The 
scrapers are set so as just to clear the turned boiler plate which 
forms the bottom of the buddle. The manner in which this 
works is as follows : The frame, with the scrapers attached, is 
set in rotation, making about twenty revolutions per minute. 



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16 RECENT IMPROVEMENTS IN TIN-DRESSING MACHINERY. 

The tin8tuff is then supplied at one end of the buddle from a 
hopper, and by means of an Archimedean screw — which has been 
omitted in the diagram — thus ensuring a regular supply of tin- 
stuff, which is an important point. A gentle stream of water is 
allowed to flow over the concave bottom from above, and the 
knives rotating in a reverse direction carry the tinstuff up 
against the stream of water, thus allowing the slimes to be 
washed away. The manner in which the knives are set has also 
a propelling and turning action on the tinstnff, by this means 
exposing every surface in turn, and at the same time gradually 
propelling the tinstuff from one end of the buddle to tne other, 
where it is eventually pushed over the side of the buddle into 
the hutch provided for its reception. The slimes are collected 
in two hutches at the foot of the buddle, and if the supply of 
tinstuff and water be properly regulated, these are found to 
contain a hardly appreciable quantity of tin. Thus it will be 
seen that by a single operation a very complete separation is 
effected ; but a very necessary point to be observed in the use 
of this machine, as also in Collom's patent jigger, to be de- 
scribed further on, is that the tinstuff to be treated must be 
first divided into its various degrees of coarseness, as upon this 
quality depends the flow of water necessary for the complete 
separation of the slimes. 

A machine designed for this purpose of separation, known 
as Cox's separator, is shown in Pig. 4. The principle is as 
follows: The stamped ore is carried from the stamps to the 
hopper. Water — with a head of at least 12 feet— is admitted 
at the bottom of the apparatus, the supply being regulated by 
the cock so as to suit all kinds of work, the machines receiving 
the ore from the stamps requiring a stronger flow of water than 
those treating the slimes, where a very gentle flow only is neces- 
sary. The water, after passing through the cock, is admitted 
into a perforated tube, through the holes of which it flows into 
the case surrounding the tube, and from thence passes upwards 
into the hopper through the annular space formed between the 
case and the taper plug attached to the screw which is in the 
centre of the hopper. This plug is hollow and has a row of 
holes round its top edge, in such a position that they are always 
above the annular space above alluded to, and part of the water 
coming from the case flows through these holes, meeting at 
right angles with the water passing through the annular space. 
Thus an active agitation of the water at the bottom of the hopper 
is produced, washing the ore and separating the coarse from the 
fine. As soon as the hopper is filled with water from below, the 
stamped ore*with its water is admitted into the hopper i'rpm 
above, and the ore to be dressed at once sinks towards the bottom 

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^1 



REGENT IMPROVEMENTS IN TIN-DRESSING MACHINERY. 17 

of the hopper. It there meets the ascending water coming 
through the annular space, and which ascends with such a Telo- 
city that only the coarser portions are of sufficient gravity to sink 
through this ascending column of water. Having thus passed 
through the annular space into the case surrounding the perfo- 
rated tube, it is there again thoroughly washed by the violent 
agitation of the water, and is thus cleaned from any slimes that 
might be adhering to it, these being carried back into the hopper 
by the ascending current of water. The coarser and cleansed 
material then sinks to the bottom of the case and is carried out 
through the side cock by the flow of water, being delivered 
thence into an ordinary square buddle. 

By means of the hand wheel and screw the taper plug at the 
bottom of the hopper can be raised or lowered so as to increase 
or decrease the area of the annular opening, and thus regulate 
the velocity of the ascending columns of water, and in this 
manner the machine can be adapted to any class of work, 
whether coarse or fine. A series of these machines would be 
necessary to perfect the work, as each one will only deal with 
one particular size of stuff. 

Another machine adapted especially for stream stuff, that is 
rough and unstamped, is Collom's patent jigger. This machine, 
as shown in Fig. 5, works in the following manner : The jig- 
ging action is produced by means of pistons fitting loosely into 
trunks and having a short vertical stroke, the length of which is 
varied according to the quality of the stuff to be dressed ; the 
finer the ore the less the stroke. The stroke is produced by 
rockers acting alternately upon each of the pistons, which are 
raised again by a spring which brings them up against an ad- 
justable stop, by which means the length of stroke is regulated. 
The space under the piston is in communication with the hutches, 
and on the top of each hutch is placed a fine wire sieve, upon 
which is placed a layer of ore varying in coarseness according to 
the quality of ore to be dressed. The stuff to be jigged is sup- 
plied through launders, together with water, and is allowed to 
fall on the sieve at one end through holes in the bottom of the 
launder, thus ensuring an even distribution of the stuff. The 
hutches are kept filled with water from a pipe, under pressure, 
and there is a constant overflow of water at the end of the hutch 
carrying away the slimes. The action given to the water by 
each stroke of the piston is such as to force it up through the 
sieves, thus partially floating the tinstuff to be jigged for the 
moment, then as the stroke returns the heavier portions settle 
to the bottom, and from thence into the hutch below, from which 
they are delivered into reservoirs by means of pipes. In some 
cases these machines are fitted with ragging gear as shown. 

o 

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18 RECENT IMPROVEMENTS IN TIN-DRESSING MACHINERY. 

This consists of a series of holes with taper plugs adjustable by 
means of thumb-screws, the object being to prevent any accu- 
mulation of stuff which is too light to pass through the sieves 
and too heavy to be carried away by the water. This, which in 
tin dressing amounts to very little, is carried away by a separate 
compartment and delivered through a hole in the bottom of the 
hutch. This machine performs its work in a highly creditable 
manner, and at Restronguet, which is the only place in England 
where it has been used for tin, it separates the tin from the sand 
and gravel with which it is associated in a most perfect manner, 
only one subsequent operation, viz. the propeller knife buddle, 
being employed to bring the ore into a marketable condition. 

These three last-mentioned machines have hitherto only been 
employed in the process of dressing stream tin, and it now 
therefore remains to mention the machinery employed in the 
final processes of dressing ordinary tinstuff. 

A very good pulverizing machine, invented by Mr. Stephens, 
of Lelant, is shown in Fig. 6. The roughs or craze are placed 
by hand in the hopper, in which a wrought-iron arm is kept 
slowly rotating, thus causing the stuff to fall towards the bottom 
and preventing it bridging up. At the bottom and on each 
side of this hopper are two small cast-iron bosses, in which are 
fixed four short arms of J-inch iron. They work on shafts in 
connection with the rest of the machine by means of geared 
wheels ; each turn of one of these arms through the hopper 
carries out a small portion of the " craze," which it deposits 
upon the inclined plane in connection with the working part of 
the machine, and on reaching the bottom of the plane it is gra- 
dually drawn through a hole in the side of the casing between 
the two grinding surfaces, the top one of which only revolves. 
The circular cases are fiDed with water so as to just cover the 
plates shown above the grinding surfaces, and which are perfo- 
rated with holes and slots, the slots being used to place pieces 
of wood in, which reaching nearly down to the rotating surface, 
stop the circulating flow of the water which would naturally 
arise from the rotation of the working parts of the machine, 
and inducing a jigging motion, thus carrying the pulverized 
stuff through the holes in the plate, from whence it flows through 
launders to the centre of small self-acting buddies, the slimes, of 
which are allowed to run away as of no value. The contents of 
these buddies are taken to the dead frames, and thence to the 
hand frames, and are eventually tossed and packed, as in the 
case of the other tinstuff which was previously separated. In- 
stead of using these pulverizers, the object of which is to reduce 
the rough waste to as fine a quality as the tin which has been 
mixed with it, and which after this has to undergo several pro- 
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REGENT IMPROVEMENTS IN TIN-DRESSING MACHINERY. 19 

eesses, the author would advocate the use of the separator 
invented by Mr. Cox, of St. Columb, in conjunction with the 

Sropeller knife buddle, which would complete the process of 
ressing without further handling, entirely doing away with 
tossing, which is a slow and tedious process, and often has to be 
repeated six or seven times. 

Tossing consists of the following operation : A large tub or 
kieve, about 3 feet 6 inches diameter, is about half filled with 
water, and the ore is then quietly slid down the edge of the 
kieve from a shovel into the water, which is kept constantly in 
agitation and rotation by means of a rotating paddle. This is 
kept revolving until the water is raised to within about 6 inches 
of the top of the kieve from the addition of tinstuff. When this 
level is attained the stirring apparatus is quickly taken out, 
and the operation of packing commences at once. This consists 
in striking blows upon the surface of the kieve with a wooden 
mallet. The time occupied in packing is generally about a 
quarter of an hour, but fine tin takes longer to pack than the 
rougher. 

When the packing is completed, which is ascertained by feel- 
ing the hardness of the tinstuff with a shovel hilt, the water is 
baled out, and tinstuff, from J inch to 1 inch deep, is then 
removed from the surface with a shovel. This stuff, which is 
termed "skimpings," is either rebuddled or taken to the frames, 
according to the nature of the stuff and its degree of fineness. 
After many tossings the bottom part is ready for the market, 
and is termed black tin. It is sola in this state to the smelters, 
who buy on their own assay, and by them the metallurgical 
process of reducing into the metallic state is performed. 

DISCUSSION. 

Mr. Perry F. Nursey said that on visiting some of the 
Jeading tin mines in Cornwall last autumn, he found that the 
managers were becoming aware of the necessity of displacing 
the rough-and-ready appliances with which they had been con- 
tent to work, by more refined mechanical contrivances. In 
many instances they were eagerly seeking for improvements, 
and were ready to adopt any suggestion which economized 
labour. It was a fact that several of the mines could not now 
be worked were it not for the more delicate manipulation of the 
ores in dressing which modern science secured. He had seen 
the various apparatus described by Mr. Cox in operation at 
different mines, and the results of working were eminently 
satisfactory. Collom's jigger and the knife middle were both 
at work at the Bestronguet Stream tin mine, with very marked 

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20 RECENT IMPBOVEMENTS IN TIN-DRESSING MACHINERY. 

success. There was one machine, however, which had not been 
noticed in the paper, but which was deserving of notice, being 
both ingenious in design and successful in operation. That was 
a pulverizing apparatus invented by Mr. Dingey, and which he 
(Mr. Nursey) found at work at the Botallack Mines. The 
Dingey pulverizers, he stated, had been introduced into the 
Corniah mines for the purpose of grinding tin ores, or what 
went by the name of " roughs " or " tailings, ' and were found to 
answer well. They would pass through a large quantity of 
stuff at a small cost for grinding, so that poor ore which was 
formerly thrown aside was made marketable. The machines 
had also been introduced in some of the Continental lead mines, 
for recrushing or grinding the lead waste, or " raggings," and 
would grind worn 15 "to 20 tons of stuff per day. The apparatus 
consisted of an iron pan, 6 feet diameter, with vertical sides, in 
which were twelve holes, 15 inches by 5 inches, fitted with fine 
punched copper plates or wire-gauze. In the inner part of the 
pan were portable plates, or shoes, made of the best white iron, 
and which were easily replaced when worn out. In the pan 
were four revolving plates, shoed in like manner, and 2 feet 
6 inches diameter. They made about 200 revolutions per 
minute, moving with the sun, whilst the pan revolved against 
the sun by means of a pinion wheel working in the outer edge 
of the pan, so that the bottom plate was always changing its 
position, and thus prevented the possibility of wearing in 
grooves. 

The machine was driven through the horizontal shaft* which 
imparted motion to a vertical shaft, having a spur wheel 
working the four pinions connected to the spindles wnich drove 
the runners in the bottom of the pan. The machine was fed by 
means of a screw working in a hopper, which passed the stuff 
to a round launder (where a stream of water was brought in), 
and from thence it passed in near the centre of the revolving 
plates, and was immediately carried under them and ground, 
and sent through the grates with great rapidity, caused by the 
centrifugal force of the water from the revolving plates, when 
it was received into a launder, conveying it direct to the 
buddies. The machine was so constructed that it could be 
bolted down anywhere to a foundation, and set to work imme- 
diately, or it could be made in light parts for exportation to 
foreign mines. A 10-inch cylinder engine was capable of 
driving it, or it could be driven by water power. In most 
mines, Mr. Nursey observed, there was a quantity of stuff con- 
taining mineral, which was unavoidably sent away with the 
waste, in consequence of the want of proper machinery for 
finishing the dressing of it In Cornwall thousands of pounds' 

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ASCENT IMPROVEMENTS IN TIN-DRESSING MACHINERY. 21 

worth of tin annually went down what was known as the " Bed 
river," which was a large stream of water running from the 
dressing floors of the mines. He (Mr. Nursey) had no doubt 
that if machines such as had been described in the paper were 
more generally used, a large percentage of that waste might be 
saved. 

Mr. F. W. Hartley said that while engineers generally 
knew pretty well what the cost of reducing iron from its ore 
was, there appeared to be less knowledge with respect to the 
cost with tin, and it would be interesting to know what was 
the cost per ton of reducing tin, and he should be glad if Mr. 
Cox was in a position to ftirnish it. He should also like to 
know the quantity of water which was employed in the wash- 
ing, although that, perhaps, was more a philosophical than a 
practical question. With respect to Cox's patent separator, he 
would inquire what force or head of water acting against the 
funnel was required to produce the active separation between 
the parts of the metal and the earthy matters. The size of the 
water-cocks had not been stated ; possibly that could be given, 
as well as the size of the openings for the delivery of water, 
with any other details of interest He (Mr. Hartley) was not 
sufficiently acquainted with the subject of the paper to offer 
any criticism, but ventured to ask a few questions with the 
view of obtaining as much information as Mr. Cox could give 
with respect to tin, of which he (Mr. Hartley) used* considerable 
quantities. 

Mr. Kitchener inquired what was the use of the tungstate 
of soda which was obtained by the process to which the author 
of the paper had alluded. 

Mr. C. Barnard asked what was the internal diameter of 
Sholl's stamps. 

Mr. Cox said that the tungstate of soda was used for fire- 
proofing fabrics for ladies' dresses, as a substitute for tannate of 
soda, which was formerly used, and which was more expensive. 
There was but a small demand for the tungstate of soda. The 
mines had a great difficulty in selling it, and they had large 
heaps of wolfram which had been raised all over the place. 
Wolfram was tungstate of iron and manganese. As to the 
price of the machines, he believed that the cost of Cox's 
separator was about 20Z. or 251. ; and that of the propeller knife 
buddle about 50Z. He had not details of the prices of the 
other machines. Cox's separator required a head of about 12 
feet of water, which was supplied at the bottom. The holes 
were about 1£ inch in diameter. The cylinder of Sholl's 
stamps was 4£ to 5 inches in diameter. 

The President said that the diagram of Sholl's stamps did 

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22 RECENT IMPROVEMENTS IN TIN- DRESSING MACHINERY. 

not show very plainly how the stamp was raised. The pressure 
took it down ; but how did it get up again ? The air of the 
piston seemed to have no connection with the stamp, except by 
air being between the two. 

Mr. Gox said that that was the only connection. When the 
piston rose the air below escaped, and the air above was com- 
pressed. The piston was allowed to work loose in the cylinder, 
and was pulled up with the crank. The cylinder and every- 
thing lifted together. 

Mr. Nurset said that he presumed that the upward motion 
of the cylinder was somewhat quicker than the action of the 
piston. 

Mr. Cox said that in Husband's pneumatic stamps, instead of 
guides there was a forked connecting-rod, which lifted the 
cylinder instead of the piston, the piston being raised by the 
compressed air. The water for cooling the cylinder was sup- 
plied down a pipe which passed through the piston-rod and 
acted as a guide for it, instead of round the outside of the 
cylinder, as in Sholl's stamps. The machine was rather more 
complicated, but he did not know whether it was better. It 
had, he believed, been patented as an improvement. 



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£3 









J 



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( 23 ) 



April 13<A, 1874. 
WILLIAM MACGEOKGE, Pbbsident, in the Chair. 

THE VENTILATION OF COAL MINES. 
By George G. Andr£. 

The late coal panic has shown us to what degree our material 
prosperity is dependent on that mineral. It would seem, 
indeed, tnat the exhaustion of our coal fields must inevitably 
be followed by the utter collapse of those industries which have 
made this country what it is, and that even a slightly decreased 
production would seriously affect their position. Coal having 
assumed a relation of such vital importance to our social 
existence, its extraction from the earth has become one of the 
foremost engineering questions of the day, and accordingly 
increased attention is now being directed to it. The author of 
the present paper has therefore deemed the time opportune 
for a discussion of some of the facts relating to what is certainly 
one of the most important subjects of mine engineering, 
namely, the ventilation of the workings. One of the effects 
of the recent panic may be seen in the greater activity shown 
at existing collieries as well as in the opening out of many new 
ones. In their haste to extract the valuable mineral there is 
danger that managers and engineers may not give due atten- 
tion to those matters which are essential to an efficient ventila- 
tion, especially in the laying out of new works. Hence another 
reason for calling attention to the subject at this time. More- 
over it is almost an indisputable fact that 90 per cent, of those 
disastrous explosions which so frequently occur are wholly due 
to a defective ventilation. Thus it appears that though the 
principles of a good ventilation are generally understood and 
acknowledged in theory, they are still far from being applied 
in practice. By the expression " defective ventilation, ' it is 
not intended to mean merely insufficient ventilation, but also 
all systems of ventilating a mine that are established upon 
false principles, quite irrespective of the quantity of air passing 
through it in a given time. Of course it is quite impossible to 
treat so large a subject in a paper like the present, and there- 
fore no such attempt will be made. All that the author 
proposes to do is to direct attention to a few essential points, 



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24 THE VENTILATION OF COAL MINES. 

and instead of adducing anything new, to simplify what is 
already known. 

It is agreed on all hands, and Parliament has recently en- 
acted, that a sufficient quantity of air should be constantly 
passed through a mine to dilute and render harmless the 
noxious gases evolved or generated therein. But there does 
not appear to be any definite understanding among mining men 
as to what constitutes a sufficient quantity, and the practice 
among careful men is to pass an excess of air in order to be on 
the safe side. No doubt this is erring in the right direction ; 
but it is better not to err at all. Besides, such a practice begets 
a vagueness of notion concerning the requisite quantity of air 
that conduces neither to correctness of judgment nor to pro- 
gress in knowledge. It may in some cases be a source of 
danger even, for a Davy larao is not safe in a violent current 
of air that has been suddenly fouled by a blower, while the 
cost of producing the current is enormously increased. Of 
course the question is an intrioate and a difficult one, depend- 
ing upon numerous conditions that vary from district to district, 
and even from mine to mine. A general solution is therefore 
not to be looked for ; but it is both practicable and highly 
desirable to lay down some definite and invariable basis upon 
which every individual case may be accurately and readily 
calculated. 

The atmosphere of a coal mine is vitiated by several causes : 
the breath of men and horses, the combustion of lights, the 
moisture of the ground, the exhalation of gases from the 
strata, and the chemical changes which are constantly going 
on in the substances exposed to the influence of the air. Some 
of these causes are constant in their action or nearly so, while 
others are extremely variable. The former we can estimate 
with accuracy ; with the latter we can deal only approximately. 

The average quantity of air breathed by man is usually 
assumed by writers on mine ventilation to be 800 cubic feet 
per minute. This quantity is, however, altogether erroneous 
as a basis on which to calculate an adequate amount of ventila- 
tion. It has been stated by eminent medical authorities that 
the mean of several hundred experiments conducted with great 
care by means of very accurate instruments was 502 cubic 
inches per minute, and that this quantity was increased to 1500 
cubic inches, or nearly three times as much, by the exertion of 
walking four miles an hour. We all know from experience that 
a much larger quantity of air is breathed when undergoing 
violent exercise than when at rest ; and we cannot therefore 
found a calculation relating to men subjected to great physical 
exertion in a mine upon what has been ascertained respecting 

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THE VENTILATION OF COAL MINES. 25 

a man lying motionless on his bed. It may be assumed that 
the average amount of labour undergone by each man and boy 
in the extraction of coal is at least equal to that of walking 
four miles an hour ; and hence the quantity of air required 
for each man will be 1500 cubic inches, or say, one cubic 
foot per minute. The miasmata or effluvia derived from the 
various secretions of the body are a potent cause of vitiation 
in the atmosphere. The unpleasant smell of a close bedroom in 
the morning is due wholly to this cause, and in ascertaining the 
state of ventilation in a room by what is known as the "nose 
test/' it is these effluvia which furnish the requisite indications. 
Moreover the air in passing over the human body becomes 
heated. These causes are greatly increased in intensity by the 
augmented temperature due to violent exertion, such as is 
undergone in mines. Added to this there is the dust caused 
by each workman floating in the atmosphere. We must there- 
fore provide an additional quantity of air to keep the atmo- 
sphere pure and cool, and tnis quantity may be taken as one 
cubic foot per minute. This allows a covering or film of air 
over his whole body about £ inch thick, which film is changed 
every minute. Each man's lamp will heat the air and foul it 
with the products of combustion to a degree requiring about 
one cubic foot per minute. Thus the quantity of air requisite 
per man will be three cubic feet per minute. A horse fouls 
about six times as much as a man, and will therefore require 
twelve cubic feet per minute. 

The foregoing may be considered the constant causes of 
vitiated air, and are easily dealt with. We come now to con- 
sider the varying causes, namely, the moisture of the ground 
and the gases evolved. It is impossible to treat these other- 
wise than approximately, but an approximation sufficiently 
near for practical purposes may be arrived at. The gases 
existing in a coal mine are chiefly carbonic acid or choke-damp 
and carburetted hydrogen or fire-damp. Other gases are 
generated, but in such small quantities that their presence is 
not of much importance, except perhaps when blasting is 
extensively practised. These two gases, carbonic acid and 
carburetted hydrogen, are continually being exhaled in greater 
or less quantities from the face of the exposed strata, and 
therefore the total quantity is to a certain degree dependent 
on the extent of surface exposed. They are given off more 
abundantly from fissures, especially in the neighbourhood of 
faults. Considerable quantities of carbonic acid are also in 
every mine due to the respiration of men and horses, the com- 
bustion of lights and the deflagration of gunpowder, all of 
which causes are subjeets of calculation. In smaller quantities, 

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26 THE VENTILATION OP COAL MINES. 

carbonic acid is formed by the fermentation and decomposition 
of vegetable matter. 

When the proportion of carbonic acid to the atmospheric air 
reaches -Arth the compound will not support combustion, and is 
fatal to Life. A proportion of iVth of carburetted hydrogen 
renders the compound inflammable. These proportions may 
be taken as the limits which must never be reached ; or, to 
farther simplify the matter, the proportion of pare atmospheric 
air must, in a mine, never be less than IJths of the total 
volume therein contained. 

The question now is what quantity of air in a dry mine, 
making but little gas of any kind, is sufficient, irrespective of 
the respiration of men and horses, to ensure this proportion 
under all conditions. This problem, as we have said, can only 
be solved approximately, but as it is mainly a matter of 
experience and calculation, a fairly close approximation may 
be arrived at. A careful investigation of this matter has led 
the author to conclude that one cubic foot of air per second for 
every 100 square yards of surface is an adequate quantity. 
This allows for the exhalation and formation of '067 cubic foot 
of impurities, that is, noxious gases, watery vapour, and solid 
floating matter per second. In other words, one cubic foot of 
air per 100 yards of surface is equivalent to a film about 
£ inch thick spread over that surface, which film is changed 
every minute. And *067 cubic foot of gases to the same 
extent of surface is equivalent to a film about *V inch thick 
formed every minute. Of course the gas is not exhaled in this 
regular way over the whole surface exposed. But the quantity 
here given is approximately that which is given off that 
surface at the worst parts under the conditions previously 
mentioned. 

This quantity of one cubic foot per second for every 100 
yards of surface may be taken as a reliable basis upon which 
to calculate an adequate ventilation. It must be borne in 
mind that the quantity is only just sufficient under the very 
favourable conditions which we have assumed, and is therefore 
analogous to the breaking strain of materials. In every case 
it will have to be multiplied by an appropriate factor of safety, 
the value of which must be determined by the conditions of 
the case. All mines are, in a greater or less degree, liable to 
give off " blowers," that is pent-up accumulations of gas which 
are liberated by the boring and driving, or by falls of roof. 
The gas issues from the blowers with a sound resembling, in 
the smaller ones, the simmering of a teakettle, and in the 
larger that of blowing off high-pressure steam. Of course it 
is quite impossible to estimate tne value of these blowers with 

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THE VEKTILATION OP COAL MIKES. 27 

anything like accuracy, just as* it is impossible to estimate the 
value of the strain to which & structure exposed to sudden 
shocks may be subjected. In both cases a sufficiently large 
factor of safety most be taken to include possibilities and to 
leave an ample margin of safety. It may be remarked that 
no system of ventilation can be calculated for the large blowers 
previously mentioned. They are fortunately of rare occurrence, 
and when one does occur, the only practicable plan is to call 
out the men until it has exhausted iteell When their presence 
is suspected, safety lamps alone should be used. The small 
blowers are more constant in their action, and are capable of 
being estimated with some degree of precision. 

Besides varying in gaseous products, mines differ in degree of 
moisture. . Blasting is also more extensively practised in some 
mines than in others. All of these circumstances will influence 
the factor of safety, the value of which must be determined 
for every individual case, and which will vary from 2 to 6. 
Let us now apply these principles to an example. Suppose we 
have to ventilate a mine in which the air-courses have a total 
length of 2000 yards, giving a total surface of say 14,000 
square yards; and, to simplify the calculation, we will sup- 
pose that the number of men and horses are 100 and 10 re- 
spectively. Respiration, perspiration, and latnps will then 
require 100 x 3 + 10 x 12 = 420 cubio feet per minute; 

and the gases, vapours, &c, will need ^ = 140 cubic feet 

per second = 8400 cubic feet per minute. Supposing the mine 
to generate but little fire-damp and to be not particularly 
wet, we may take the factor of safety at 3, whicn will give 
(840° + 420) x 3 = 26,460 cubic feet per minute as the 
adequate amount of ventilation. In this case we have taken 
the surface and the factor of safety for the entire mine ; but 
when, as it usually is, the mine is divided into several districts, 
which are aired by separate currents, the air must be appor- 
tioned according to the surface of each district and the factor 
of safety determined by the nature of the seam or the con- 
ditions of the workings. Thus the factor of safety may vary 
from district to district 

When the proper quantity of air has been determined, the 
next question is, how to get it through the workings. One mode 
of effecting this is to provide contracted air-ways and to give 
the ventilating current a high velocity. Another is to have 

rious air-ways and a low velocity. J?or economical reasons, 
former is but too frequently adopted. In many cases a 
drift is driven with an insufficient sectional area ; in other cases, 
falls of roof, the creep of the floor, and other causes reduce the 

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28 THE VENTILATION OP COAL MINES. 

dimensions of an air-passage to those of a mere creeping hole. 
Fully 25 per cent, of the air-courses in collieries which are 
now being workei, abd in which the ventilation is said to be 
perfect, can only be entered by a man in a crawling posture. 
The economy of a system that lays out works in such a manner, 
or that allows them to get into such a condition, is more than 
doubtful. The drag of the air, that is, its retardation by con- 
traction and friction, is enormously increased thereby, and the 
consumption of fuel in the furnace, or in the engine when a 
mechanical ventilator is used, is augmented in a like propor- 
tion. But even when the additional cost of fuel is incurred, the 
friction with small passages and high velocities is so great that 
it is impossible to ensure sufficient ventilation at all times, and 
hence there is the constant risk of accident, with, its accom- 
panying danger to life and property. It may therefore be 
laid down as one of the essential principles of an efficient 
ventilation, that spacious air-ways are indispensable. A limit 
that may be adopted with advantage is, that all air-ways other 
than shafts should allow a sufficient quantity of air to pass with 
a velocity not exceeding 6 feet per second. 

Another important fact connected with the dimensions of 
air-ways is, that the return passages reauire a larger sectional 
area than the intake passages. When tne ventilating current 
enters the return ways from passing through the workings, it is 
laden with the various gases that are generated in a mine, 
watery vapour, the solid products of combustion and coal dust, 
and its temperature, and consequently its bulk, is considerably 
increased. Thus it has lost a great part of its elasticity and it 
drags more heavily. To compensate this, its friction should be 
lessened by increasing the sectional area of tfie passage. To 
ensure a proper state of ventilation there should be two return 
ways, each equal in sectional .area to the intake. As far as 

J>racticable, the air-courses should have at. all parts of their 
ength the same sectional area. It is, perhaps, hardly neces- 
sary to remark that they should be kept free from all obstruc- 
tions, such as projecting pieces of timoer or stones. 

One of the most effective means of diminishing the friction 
is to shorten the runs by dividing the workings into districts 
and ventilating each with a separate air-current. Thus, a shaft 
12 feet in diameter will afford sufficient area for five different 
air-ways each of 20 feet area. This system of splitting the air, 
as it is called, though well known, is not adopted so extensively 
as it ought to be. There are many mines in which the old un- 
wholesome and dangerous practice of passing the air through 
in one column from the downcast to the upcast shaft still prevails, 



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THE VENTILATION OP COAL MINES. 29 

though the evils attending it have long been acknowledged by 
the majority of viewers. An additional and great advantage 
possessed by the system of ventilating by districts is that of 
confining the effects of an explosion to a small part of the 
workings. In all cases of splitting the air, the split should be 
made as near the downcast shaft, and the several branches 
reunited as near the upcast as possible, and the air-ways between 
the shafts and the points where the branches separate and 
reunite should have a large sectional area. 

The distribution of the air through the workings requires 
great skill. There are, indeed, few matters connected with 
mining that test the skill and ability of the engineer more than 
this. A very slight variation in the direction of the ventilating 
current may make all the difference between a good and a 
defective, and consequently a dangerous ventilation. And yet 
this important duty is often left to ignorant hands. No doubt 
the men who are entrusted with this important work are expe- 
rienced men, and men who on that account would be called 
practical. But there are things which experience alone cannot 
teach, at least in the lifetime of a single individual. A certain 
amount of scientific knowledge and an acquaintance with col- 
lateral subjects, such as the composition of gases, the nature of 
fluids, and the laws which they obey, are absolutely necessary 
to enable a man to manage efficiently the ventilation of a mine. 
And such knowledge is part of a liberal education. 

The essential conditions of a good distribution are : (1) That 
the air shall not pass from the broken to the whole workings ; 
and (2) that an explosion shall not take the air off the men at 
the faces of work, or reverse its direction. 

The author does not hesitate to assert that three-fourths of 
the explosions that occur, and that result in such a lamentable 
destruction of life and property, are caused solely by the neglect 
of the former of these conditions, and are therefore preventable ; 
and that a large proportion of the deaths that result are due to 
the neglect of the latter conditions ; for in most cases fewer 
men are killed by the direct effects of the explosion than by the 
after-damp. It does, indeed, seem strange that such an ignorant 
mode of distributing the air should still be commonly adopted. 
When the ventilation is in uneducated hands we may attribute 
the practice of the pernicious system to ignorance and want of 
skill ; but when, as is sometimes the case, we find the practice 
perpetuated under the authority of men eminent in their pro- 
fession, we are forced to believe that a criminal economy is at 
the bottom of the matter. 

As an illustration of this faulty mode of distribution, we will 

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80 THE VENTILATION OF COAL MINES. 

take an example from actual practice as given by a recent writer 
on ventilatiou, which example resulted in a serious explosion. 
It will be seen from diagram No. 1 that the air comes up the 
south advance bords, and as it returns it passes through the 
barrier walls. It is then coursed in threes through the broken 
or pillar workings, returning by the east winning headways. 
By this system the working faces are aired in conjunction with 
the broken mine ; that is, the men in the most northern portion 
of the faces of work are supplied with air that has first passed 
through nearly the whole of that district Now, if no danger 
were to be apprehended from fire-damp, the system is a most 
pernicious one, inasmuch as it supplies the men at the working 
faces with air that has been fouled with all the impurities that 
may be generated in a mine. But what happened in this 
instance ? At the spot marked A, a fall of the roof occurred, 
liberating one of those pent-up accumulations of gas which are 
frequently met with. The gas escaping from this blower was, 
of course, carried along by the ventilating current, fouling the 
rest of its course, as shown by the hatched portion, until it 
reached the faces of work F, where it came in contact with 
the men's naked lights. 

Now suppose the ventilation earned out in the manner shown 
in diagram No. 2. The air is taken directly to the whole of 
the working faces, so that the men get the current pure as it 
enters from the downcast shaft. This is effected by placing a 
light stopping the ends of each bord on the east side of the 
headway's course. When the ventilating current reaches the 
northernmost bord it is passed through a regulator B, and 
coursed back in threes. With this arrangement it will be at once 
seen that the accident could not have occurred, as the gas could 
not by any possibility get to the working faces, but would be 
carried out by the air-current into the return passages, where 
none but the waste-men with their lamps can go. In this 
instance there is no difficulty in substituting the correct for 
the incorrect method of distributing the air; but sometimes 
conditions will arise demanding for their due fulfilment con* 
siderable knowledge and great practical skill, and it is in these 
instances that the ordinary man fails. 

The case selected as an illustration is a very bad one, and 
though it might be taken as a fair example of the system as 
carried out some years ago, it would probably be difficult to find 
a parallel case now. But in a lesser degree the same system 
still obtains in half of our collieries. And until it has been wholly 
rooted out the list of deaths from explosion will continue to be 
long. Perhaps Parliament may some day deem it necessary to 
include this matter in the Coal Mines Regulation Act. 

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THE VENTILATION OP OOAL MINES. 31 

The second condition is scarcely of less importance than the 
first, as it deals with the effects of an explosion should such an 
accident occur from any unforeseen cause. The ventilating 
current will always take the shortest course to the upcast shaft. 
If, in consequence of an explosion, the doors or stoppings are 
injured, a large portion of the workings may be left entirely 
without air at a time when it is most needed, namely, when the 
passages are foul with the after-damp or carbonic acid gas pro- 
duced by the explosion. To prevent such an occurrence the 
distribution should be so arranged as to preclude the possibility 
of the current of air being diverted from its proper course before 
it has left the working places, or of being stopped altogether by 
an injury to the return passage. Suppose, for example, instead 
of a stopping at B, diagram 2, we haa a door, or a pair of doors ; 
neglect of or injury to this door would instantly take off the air 
from the whole district. A door in such a position should 
therefore be avoided, and the stoppings made strong. All per- 
manent stoppings should be built of brick or stone and well 
plastered ; they should also be well backed, especially those by 
the side of the main ways, which should have five or six yards 
of stowing behind them. Whenever a crossing is necessary for 
the return it should, if possible, be by a stone drift over or 
under the main way. The additional cost thus incurred would 
be more than compensated by the additional security obtained. 
Were all these precautions duly observed, mining would be 
freed of half its perils. A strict supervision would be all that 
was necessary to protect the mine against the danger of an 
explosion occasioned by any but unforeseen causes. Such 
supervision is indispensable in all cases to ensure the proper 
quantities of air being apportioned to the several districts, and 
the needful precautions constantly taken to maintain a steady 
uniform current of air. Without this the best system must 
prove ineffectual. 

In concluding these somewhat desultory remarks, the author 
feels that he has done but scant justice to his subject, the impor- 
tance of which can hardly be over-estimated, involving as it does 
the health and lives of nearly half a million of men. Whether 
or not he has succeeded in placing clearly before the members of 
this Society the leading facts connected with the subject, and in 
drawing their attention to the essential conditions of an effi- 
cient mine ventilation, too frequently overlooked, is not for him 
to determine. If he has done so he has attained the object he 
had in view in preparing the present paper. 



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32 THE VENTILATION OF COAL MINES. 



DISCUSSION. 

Mr. Baldwin Latham said he would offer a few remarks in 
order to open the discussion, but his observations would be on 
the general question of ventilation rather than with particular 
reference to coal mines. He had certainly given some atten- 
tion to the ventilation of coal mines when studying the ventila- 
tion of sewers ; but he had found that the system of having oue 
downcast and one upcast shaft for the ventilation of coal mines 
was comparatively easy to carry out, but that it was not at all 
applicable to sewers. From his examination of a large number 
of coal mines he was convinced that the observations which had 
been made by Mr. Andr6 in his paper were of very great value. 
The paper did not touch upon the particular means which were 
adopted for the ventilation of coal mines, but it simply brought 
forward broad facts which it would be well for all interested in 
such matters to bear in mind, and which showed that there 
never could be safety without a superabundance of fresh air. 
There was not sufficient attention paid to the ventilation of a 
mine as the workings were worked out, or as the material was 
extracted. In his opinion a new mine required far less air than 
one which had long been at work. The little passages which 
were shown in the diagrams were air-channels ; and in a new 
mine the cubic capacity of those channels would be compara- 
tively small; but when the mine was worked out the cubic 
capacity became greater. When gases escaped or blowers oc- . 
curred, the passages and goayes acted as gas holders by means of 
which gas could be accumulated. In an old mine the same in- 
take and the same volume of air passed through it as in anew 
mine, although the cubical capacity in the old mine was greater. 
The chances were that in old mines the whole area might 
become occupied with gas which, by the admixture of the 
atmospheric air in limited quantities, would be rendered ex- 
plosive. Instead of being diminished as the mine was worked 
out, and the cubical capacity of the mine became greater, the 
amount of air ought to be increased, and not only so, but ade- 

Suate mechanical arrangements ought to be introduced by which 
le air could be conducted through the vacant spaces so as to 
completely ventilate the mine. 

It was a disputed point whether natural or mechanical means 
ought to be adopted for ventilating mines. By mechanical 
means, he meant the use of steam as a mechanical power, for 
either driving air into the mine or sucking air out. The plan 
of driving air into a mine was called the plenum system, and 
the plan of drawing air out was called the vacuum system. The 
natural system of ventilation consisted of those methods in which 



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THE VENTILATION OP COAL MINES. 33 

the air of a mine was heated by ordinary combustion, so that 
they got a column of heated atmospheric air which was consider- 
ably lighter than an equal column of cooler air, and by this dif- 
ference in the weight of respective columns of air motion was 
produced. Air upon being heated dilated *i^th of its own bulk 
for every degree Fahrenheit. Hence he fully corroborated the 
statements of Mr. Andr6, that the passage for the exhausted 
air required to be far larger than the passage for the intake air. 
Air always passed into a mine at a temperature far lower than 
that of tne air some hundreds of yards below the surface of the 
earth. The air of a furnace was applied in order to heat air 
in excess of atmospheric heat, and create that current of air 
which was necessary to aerate every part of the mine. A cubic 
foot of air heated 50 or 60 or perhaps 80 degrees would occupy a 
far larger space than it originally occupied when it entered the 
mine. This caused the necessity for increasing the size of the 
air-passage for all air which had once passed through the mine. 
If tnis was not done there would be a contraction, and contrac- 
tion meant waste of force, and it also meant retardation of 
ventilation. Further, it was possible when there was a con- 
tracted passage that from some sudden cause, such as the 
explosion of gunpowder in the mine, the whole current of venti- 
lation might oe changed in the opposite direction. Therefore 
it was needful in all cases of mine ventilation to make the 
passage of the air as easy as possible, from the place where it 
entered to the place where it passed out. If the passages were 
uniform throughout, some circumstances might momentarily 
change the direction of the air, and the result to those who were 
labouring in the mine might be an immense loss of life. Hence 
the necessity of producing enlarged passages for the easy exit of 
the air that had been used in the mine. Air would always take 
the shortest passage. We might make passages for it, but it 
would not follow the route prescribed tor it if it could get 
awav by any shorter cut. 

With regard to the diagram No. 2 it was not sufficiently ex- 
plained to the meeting mat all the working face was simply 
the face upon the left of the letter K. All to the right of that 
letter might be considered to be faces in which men were not 
at present working. The air was brought immediately to those 
working faces, and returned again to the other side ; but in the 
intermediate space there was no present working. The result 
was that every person in those faces had perfectly fresh air. So 
long as no foul air came from the intermediate portions of the 
mine, the persons working in the mine would not be affected. 
The foul air from those portions would pass away with the out- 
take, and it could not possibly come into contact with the work- 

D 

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34 THE VENTILATION OP COAL MINES. 

ing faces ; and its not coming into contact with those faces, and 
probably with those sources from which danger might arise, 
from the carelessness of men, would be extremely advan- 
tageous. But unfortunately the diagram failed to show the 
case in which the whole of the columns were worked out ; but 
still in that case the principle held good. The system was a 
judicious one ; and it was a very adverse case which was shown 
in the diagram, for he did not expect that any colliery engineer 
would leave a small portion of his workings (say the upper 
part) completely isolated from the lower part, but he would 
b*»gin at the extremity of his workings, and work away so 
that he would completely shut off a goaf, that is, a portion 
which was worked out. The engineer would so arrange that 
such a thing as was shown in diagram No. 1 could never 
occur, and he would really get fresh air in the whole of his 
workings. 

When colliery engineers studied the matter they always broke 
down the coal when the mine was worked out, in such a way 
that the occurrence of such a state of things as was shown in that 
diagram would be impossible. This question of ventilation was 
one of very extreme importance. Our home comforts depended 
upon it, and in fact, unless some degree of security and safety 
was given to the miners, the members of the Society could not 
be assembled in that room that evening, for the light they were 
using was derived from coal. They must all sympathize very 
much with the collier in his arduous undertakings, and espe- 
cially when those undertakings were not protected with that 
amount of scientific knowledge which was necessary to secure 
his well being. 

Mr; Arthur Bigg said that it appeared from the diagrams 
as if the ventilation was all conducted from one shaft That 
was an old plan not now carried out in new collieries. 

Mr. Baldwin Latham explained that the diagram repre- 
sented only the section of a mine. 

Mr. Arthur Bigg said that the mechanical system of venti- 
lation most generally adopted consisted in the use of fans, and 
they might be employed in two ways either for forcing air into 
the mine (the plenum system) or for drawing air out (the 
vacuum system). Of those two, even on theoretical grounds 
only, the vacuum system appeared the best, for in the plenum 
system whatever moisture happened to be contained in the 
atmosphere at the time the air was compressed would be liable 
to be deposited ; but in the vacuum system, on the contrary, the 
air being attenuated was in a condition to take up a far greater 
amount of moisture on leaving a mine than it could hold on 



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THE VENTILATIOX OF COAL MINES. 35 

entering. No doubt Mr. Andr6 was perfectly correct with his 
remarks on tbe dimensions of the passages, for in order to 
force a certain quantity of air through them if the passages 
were half the area, the air would have to travel with double 
velocity, and hence require about four times the power to drive 
it. There was an enormous economy in having the passages 
large, and the saving of three-quarters of the coal which 
would have to be burnt when narrow passages were used was 
surely a sufficient compensation for any expense in making 
them so large that a man could walk erect instead of being 
obliged to crawl on his hands and knees. 

On one occasion he (Mr. Rigg) went down a coal pit ; the men 
seemed only anxious to show the effects of the fire-damp by 
holding up their safety lamps against certain " blowers," and 
having their light obscured or put out altogether. Under such 
a system as Mr. Andr£ had recommended it would have been 
rather more comfortable. Mr. Andr6 said that the exit should 
be twice the size of the intake, but he (Mr. Bigg) supposed that 
such a statement applied only to the plenum system, for he 
could hardly imagine such an increase of size would be neces- 
sary in the vacuum system, where the velocity of the air when 
leaving would be so much greater than that of the air entering ; 
but in the plenum system no doubt the outlet should be twice 
as large as the intake. Mr. Andre's plans were most interesting 
and important, and persons were far too apt to make small 
openings for ventilation instead of large ones, not only in coal 
mines but wherever ventilation was required. 

Mr. Druitt Halpin said he believed that mining engineers 
reckoned that they did a pretty good duty on the average in 
the natural system of ventilation, if with a consumption of 
50 lb. of coals an hour they dislodged a quantity of air 
represented by 33,000 foot-pounds per minute in one horse- 
power. On the mechanical system, in some of the best- 
arranged methods, they worked at about 10 lb. per horse- 
power per hour. With good Guibal fans, which nad lately 
been introduced from Belgium, they got a duty out of the 
fan of 40 or 45 per cent, of the power put into the engine. 
They used 8 or 10 lb. of coal per horse-power per hour. It 
was therefore a matter of calculation what should be laid out 
in the mechanical arrangements. Coal at the point of pro- 
duction was often so cheap as sometimes not to require to be 
very accurately considered. The mechanical method was the 
most certain of the two, and was gradually gaining ground. 
The great advantage of the Guibal system of fans was that the 
fans did not allow a mass of mechanical power to pass them 

d 2 

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36 THE VENTILATION OF COAL MINES. 

and come away without being utilized. A large duty was got 
out of the fans by gradually diminishing the velocity of the 
issuing air, and letting the whole body of the gases go away at 
an almost nominal velocity. A movable shutter worked up and 
down to regulate it. 

Mr. Andr£, in replying upon the discussion, observed that 
with regard to Mr. Baldwin Latham's remarks about the old 
and new mines, he (Mr. Andre) thought that they were quite 
in accordance with nis remarks in the paper, because he pro- 
portioned the quantity of air to the area exposed, and therefore 
in an old mine, where there was a much larger area exposed 
than in a new one, more air would have to pass through. With 
respect to the goaf, or the portion worked away, as the pillars 
were worked away, air-passages would still be left through it. 
It would be altogether wrong to leave it with pent-up accumu- 
lations of gas, so as to make it anything like a gas- holder. . He 
knew that was sometimes done, but it was a very dangerous 
practice. Passages must be left clear to carry away all the 
gases which were given off in the goaf Goaves were very 
dangerous places, and many explosions had resulted from 
proper care not being taken with them. The air ought to be 
passed from the goaf directly into the return passages. One 
speaker had doubted whether such a practice as represented 
in diagram No. 1 was ever carried out. That diagram, how- 
ever, represented a case which existed in actual practice, and 
a bad accident occurred there. It was true that the system 
shown in that diagram was not adopted very extensively, but 
there were very few mines in which the principle was not 
adopted in some degree even now, and he had noticed that 
nine out of every ten of the accidents that had taken place 
had been due to that cause. One which occurred the other 
day was due to it. It was very frequently the case that the 
air was carried in that way for a short distance ; but even if 
the distance was short an explosion would take place if a naked 
light were carried there. 

Mechanical ventilation was certainly coming more into use. 
In some respects it was preferable to the furnace, but he was 
not altogether in favour of it It was entirely dependent on 
the fan, and if the machinery broke down the ventilation was 
stopped at once through the whole mine. In the case of 
furnace ventilation, it would be a difficult thing to put out the 
fire all at once, and if that was done the shaft would be still 
hot, and the ventilation would be carried on for some con- 
siderable time ; that was a great advantage. It was true that 
the engine burnt less coal than the furnace, but the coal had to 



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THE VENTILATION OF COAL MINES. 37 

be brought up to the engine before it could be burned, and 
though the cost of bringing it up was not much, still it was 
something. He believed that the furnace system, taking it all 
together, was better than the other. Wifh regard to the 
plenum system, he did not think that that would do at all. 
The vacuum system was the only one to be adopted, and in 
that case he certainly thought that the return passages would 
require a large area just the same, because when the air passed 
down the downcast, it was at a certain temperature, and had a 
certain volume, and in passing through the workings it got 
considerably heated and expanded. He believed that an 
additional area would be required, whichever way the air was 
expelled. 

A remark had been made about the proportion of the intake 
to the outlet being as 1 to 2. When he (Mr. Andr6) spoke of 
the factor of safety he was not referring to the size of the return 
passages. The factor of safety referred to the auantity of air 
passed through the whole mine or a whole district. The 
sectional area of the returns compared to that of the intake 
should be as 2 to 1. The stalls or passages must not be con- 
sidered to be full of impurities. The impurities were gradually 
fven off, and there was not such a vast volume to carry away, 
he gases exuded all over the surface in small proportions 
relatively to the quantity of air to be passed through the mine,, 
and it would be sufficient to make the return passages twice as 
large as the intake. He might remark that the mine repre- 
sented in the diagram was ventilated by two shafts, but the 
diagram showed only one district of the mine. The air was 
carried from this district directly to the upcast shaft. There 
might be several districts. 

The President, in closing the discussion, congratulated the 
members of the Society both on the paper and on the discussion 
which had followed it. Those who nad taken part in the dis- 
cussion seemed to agree pretty much with Sir. Andr£, and 
that was a good proof that the principles laid down in the 
paper were sound. Nothing could be more important than the 
ventilation of coal mines, when we considered the enormous 
waste of life which frequently occurred for want of such venti- 
lation. Accidents became all the more lamentable when it was 
found that a great many of them might be averted. No doubt 
many of them were due to the carelessness of the miners them- 
selves, from that insane disregard of ordinary precautions which 
familiarity with danger often engendered; but still the men 
were aware of those dangers, and they worked in the mines, 
and he really thought that they showed as much courage in 



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38 THE VENTILATION OF COAL MINES. 

doing so as soldiers in a field of battle. Perhaps there was 
as much loss of life in collieries as there was in many battles. 
There was nothing in the paper but what was practical, and 
Mr. Andre had done the Society great service in reading such 
a paper. 



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( 39 ) 



May 4<A, 1874. 
WILLIAM MACGEORGE, President, in the Chair. 

MODERN SYSTEMS OF GENERATING STEAM. 
By N. J. SUCKLING. 

The great progress that has been made of late years in the 
systems of generating steam is principally the result of its com- 
mercial success, and the facility with which it can be generated 
and adapted to the various requirements of mankind. Its 
application on an extensive scale, both at sea and on land, has 
given an impetus to improvements in the existing forms of 
boilers, and also paved the waj for an improved generator. 
Long since, theoretical deductions indicated the economical 
advantages to be derived from the employment of high steam 

Sressures, combined with high grades of expansion in the cylin- 
er. The practical difficulties that stood in the way having 
been gradually and successfully overcome, the result is that 
where 10 lb. pressure was commonly adopted forty years ago it 
has been slowly increasing to 701b. up to 150 IK, and the more 
general employment of the higher pressures will be demanded 
as the great advantage of using steam expansively becomes more 
generally recognized. 

Upon the proper efficiency of the boiler depends the efficiency 
of the engine. It is therefore of the utmost importance to 
devote the greatest attention to the structure in which the vital 
principles of the engine are generated. Boilers, because of un- 
avoidable peculiarities, and to meet different requirements, are 
constructed of various forms. For stationary purposes the 
cylindrical is the favourite type, while for marine use the 
multitubular is generally adopted. But the introduction of flues 
and tubes destroyed their former simplicity, and admitted 
impediments to thorough examination and cleaning. The 

Seatest disadvantage of these boilers is the large diameter of 
e shell, which is subjected to excessive strain caused by the 
unequal expansion of their parts. The upper portion being at 
a higher temperature than the lower produces leakage at the 
seams and rivets, which inequality of temperature also in- 
juriously affects the flues and tubes. Steam users have there- 
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40 MODERN SYSTEMS OF GENERATING STEAM. 

fore good reasons for complaint at the continual and heavy 
boiler-maker's bills. The increase in the thickness of plates 
necessary for the high pressure the boilers are to withstand has 
led to difficulties in the construction and keeping of them in 
repair. Moreover, the area of the fire-grate is necessarily 
limited to the diameter of the flues, and as there is not suf- 
ficient room for the combustion of the fuel, a large quantity 
passes to the funnel or stack in the form of unconsumed gas. 
Ample space for mixing with a proper supply of atmospheric 
air is indispensable to ensure complete combustion and economy. 
The grates being narrow they must be increased in length to 
obtain the necessary area. The author well knows the difficulty 
of keeping the bars properly covered, especially at sea in bad 
weather, for whenever they exceed 6 feet they are almost certain 
to be productive of waste, as grates above this length are gene- 
rally beyond the control of the stoker. 

The positions of the heating surfaces of boilers in common use 
are not at all favourable to the rapid absorption of heat, the 
flame and hot gases travelling nearly parallel with the plates, 
in place of striking them at right angles. This grave defect 
will be better comprehended on referring to Fig. 1. In this 
diagram the top plate of the flue of a Cornish or marine boiler 
is represented by the horizontal line, under which are seen a 
number of circles representing atoms of gas. At first these are 
of a bright red, denoting high temperature ; as they move along 
the flue, however, they are cooled down and, sinking, give place 
to others, but the difference in density is small, and consequently 
their tendency to sink. They are therefore carried nearly to 
the end of the flue before they can getaway from the plate. It 
will also be noticed that ihe central or principal portion of the 
gases does not come in contact with the plate at all, and were 
it not for the partial breaking up and mixing of the gas currents 
by side flues or by passing through small tubes, the loss of heat 
would be immense. But this mixing of gases is very defective, 
and the products of combustion escape up the chimney at a high 
temperature. To lessen this defect, cross tubes have been in- 
troduced into the flues with a decided gain as to efficiency ; 
they not only assist in mixing the atoms of gas, but at the same 
time afford the most efficient receiving surfaces, and the circu- 
lation of the water is improved. The importance of breaking 
up the body of heated gas, and compelling every portion of it to 
come successively into contact with the surface to be heated is 
apparent when we consider at what a great speed the escaping 
gases travel, and the short time they act on the plate. It has 
been proved that in ordinary boilers, worked with a good 
draught, these gases travel at a velocity of 6 feet per second ; 

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MODERN SYSTEMS OF GENERATING STEAM. 41 

so that in a Cornish boiler 30 feet long the time occupied by them 
in passing through the main and side flues — 85 feet in entire 
length — is only nfteen seconds. The length of run in marine 
boilers is considerably less, the time in passing through the flue 
and the tubes of one 15 feet long, not exceeding five seconds. 
It is therefore of the utmost importance that the absorbing 
surfaces should be arranged so as to be as efficient as possible, 
and this can only be accomplished by making the flame and 
gases travel at right angles to the direction of the plate, which 
is incompatible except with water-tube generators. 

Another defect, common to all boilers having a shell of large 
diameter, is that they commence working at the full steam 
pressure for which they were designed. After a few years the 
pressure is reduced through deterioration, causing a corre- 
sponding reduction in the speed of the ship. Eventually new 
boilers are required, or, if such valuable space can be spared, an 
auxiliary boiler is added, and ihe consumption of fuel is in- 
creased thereby. They are also very unwieldy, and occupy a 
large space. These are some of the powerful arguments that 
are engaging the attention of engineers and employers of steam ; 
and as there appears no hope of any solution of the problem, or 
further improvement being effected in this direction, water-tube 
or sectional boilers are beginning to attract public notice. 
With them no large shell is Accessary (seams and rivets are 
avoided), the danger and expense of .keeping it in order are at 
once removed, the water being subdivided and contained in 
tubes of moderate diameter, outside which the flame and heated 
gases circulate on their way to the stack or funnel. Much has 
been said in favour of water-tube boilers, but as there appears 
considerable diversity of opinion as to the conditions affecting 
their successful working, and the most effectual means of putting 
these conditions into practice, it is essential to consider the 
various points connected with the subject, and to compare them 
with two boilers at present before the public In doing so it is 
unnecessary to enter into a scientific investigation of the prin- 
ciples, but rather to give a general description, trusting not to 
be charged with partiality or unfairness to those who may differ 
from us. However far advanced our experience in boilers of 
the ordinary type, this knowledge does not apply when designing 
water-tube generators, as the latter form a distinct class, re- 
quiring a different arrangement and combination of parts to 
give the maximum of efficiency. And the writer thinks many 
of the failures have been the result of misconception of the 
principles, and of faults in material and workmanship. The 
idea of using sectional boilers is very old, for in the infancy of 
the steam engine attempts were made to work it with high- 
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42 MODERN SYSTEMS OF GENERATING STEAM. 

pressure steam ; and the generators employed were composed 
of tabes of moderate diameter, having the water for evaporation 
within them. But owing to frequent mishaps these boilers fell 
into disuse, and the advocates of low pressure took the ascen- 
dency, and held their ground until late years. With improved 
machinery and modern appliances for manufacturing tubes, and 
a better knowledge of the subject, we may reasonably expect 
water-tube generators to supersede the present forms of land 
and marine boilers, for undoubtedly, the principle has much to 
recommend it So long as fuel was cheap and abundant, and 
employers of steam were satisfied with the existing state of 
things, it was mere waste of time to endeavour to introduce a 
generator of this type. However safe and economical it may 
have proved, the powerful vested interests and prejudice that 
would oppose its adoption would not compensate — in a pecu- 
niary sense — the exertions of its inventor; and this opposition 
has dealt the death blow, or retarded the introduction of many 
a valuable invention, which in later years has proved of the 
greatest value to society at large. Happily such is not the 
present state of feeling, and there is every prospect of the merits 
of water-tube boilers being fully appreciated. 

The great economy to be derived by the adoption of high 
steam pressures is now well recognized, and compound engines 
are rapidly superseding the older types. With these the 
present consumption of fuel at sea, using steam at 60 lb. 
pressure on the square inch, averages 2J lb. per indicated horse- 
power per hoar. The lowest consumption ever attained was 
attested by the late Professor J. Macquorn Bankine to be 
1*018 lb. per indicated horse-power per hour, the pressure of 
steam being 115 lb. per square inch. By still further increasing 
the pressure the consumption of coal need not exceed 1 lb. per 
indicated horse-power per hour, or about one-half that of the 
best results at present obtained. With water-tube generators 
we may work at 150 lb. pressure on the square inch with little 
danger, and in one instance even 240 lb. is ventured upon with 
no injurious effects. Having thus far premised the subject, the 
next point worthy of consideration is the conditions that 
must be fulfilled in order to produce a really good generator. 

(1) The tubes must be so arranged as to present the most 
effective heating surfaces to the flame and heated gases. 

(2) Every facility must be provided for the escape of the 
steam, and the supply of water to the tubes to prevent over- 
heating. 

(3) They must be so connected that no destructive ex- 
pansion can take place, which would produce leakage at the 
joints. 

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MODERN SYSTEMS OF GENERATING STEAM. 43 

(4) They must be easily cleaned and examined internally and 
externally, and deposits in the water collected in tabes not ex- 
posed to heat. 

(5) They should be constructed so that the parts are readily 
disconnected, and all joints outside. 

(6) A large water surface should be provided to prevent 
priming ; also sufficient steam and water storage. 

The author thinks the foregoing rules embrace the subject, 
and he will proceed to express his views in the order in which 
they stand. 

Firstly, the tubes must be so arranged as to present the most 
effective heating surfaces to the flame and heated gases. In 

S lacing the tubes in the furnace, they must be so fixed that the 
ame and heated gases strike the heating surfaces at right 
angles in place of sliding along them, as is the case in Cornish 
and other toilers. And it is advisable that the tubes be con- 
nected in such a manner as to break joint (see Fig. 2). The 
arrows show the zigzag course of the products of combustion on 
their way to the stack or funnel. It will be noticed that the 

Sees strike the lower tubes, lap round each, and on leaving 
em are thrown against the next tier of tubes, and so on until 
they leave the boiler. In this manner the tubes break up the 
flame currents, and sufficient time is allowed for the absorption 
of heat, and the gases leave the boiler only a little in excess of 
the temperature of the steam. In no other arrangement of the 
tubes can these advantages be so fully and simply attained. 
When they are placed in vertical tiers, as in Fig. 3, the heating 
surfaces are not so effective; the reason of this is easily 
understood on referring to the sketch, where it will be seen that 
some of the gases pass upwards between the tubes without 
striking them. It is true that baffle plates have been fixed 
between the tubes to mitigate this defect, but they are quite 
unnecessary, as the arrangement in Fig. 2 is far preferable. 
When heated air is in contact with a surface much colder than 
itself, the amount of heat given out is not only a question of , 
time, but also of position of the receiving surface. And in 
most boilers the flameway is divided by one or more dividing 
plates, which allow a longer run for the products of combustion 
than could be obtained without some such device. Their use 
also secures a more regular diffusion of heat over the whole 
length of the tubes. From what has been said, it is evident 
that if the tubes of the boiler are vertical the course of the 
flame should be horizontal. If, on the contrary, the tubes are 
horizontal, then the products of combustion should travel verti- 
cally. In estimating the value of heating surface, we must 
consider not only the actual surface of a boiler, but also its 

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44 MODEEN SYSTEMS OF GENERATING STEAM. 

effective surface. The first arrangement of tubes gives the 
largest effective heating surface, and should thereby be adopted. 

Secondly, every facility must be provided for the escape of 
the steam and the supply of water to the tubes, to prevent 
overheating. This rule appears the most difficult to fulfil, and 
has given more trouble than any other connected with the con- 
struction of the water-tube boiler. In all boilers the expedients 
for maintaining a proper circulation of the water, so that the 
flame may act upon solid water and not upon a mixture of 
water and steam, have been greatly neglected, and the con- 
sequence is that a much larger amount of surface is required 
than would otherwise prove necessary. The metal is often 
bent and buckled by being overheated, and priming takes 
place to an inconvenient degree. A rapid circulation of the 
water will not merely render the boiler more durable by pre- 
venting overheating of the metal, but as the ascending curreut, 
by carrying off the steam and presenting a new surface of 
water to be acted upon, keeps the tubes cool, they are in a 
better condition for absorbing heat from the smoke than if the 
metal had become overheated from the entanglement of steam 
in contact with it, which impedes the access of the water and 
prevents the rapid absorption of heat that would otherwise take 
place. The want of a constant supply of water to the tubes 
and impediments to the rapid escape of the steam were the 
chief causes of failure of the 'Montana's' boilers; and the 
author will therefore state his views in extenso. Theoretical 
laws are unaffected so long as the heating surfaces are wet 
without intermission, yet if any portion is stripped for a 
fraction of time, then that portion for that time is of no value. 
While cold, every part of the heating surface is wet, but 
unfortunately this is not the case when the boiler is heated. 
Most generators, till within a short time back, were designed 
without sufficient attention having been paid to this, and the 
results were consequently unsatisfactory. The water can only 
be kept in constant contact with a particular part, by inducing 
a system of currents in the direction of the heated plate. 

Theoretically the best form of boiler to extract all the heat 
from a plate would be to make that plate into a tube of 
moderate diameter. It does not affect the results whether 
steam is generated in a test tube over a spirit lamp, or in the 
boilers of a steamship ; and to simplify the principle it may be 
added that if a horizontal tube of glass containing water is 
heated at one portion of its length to such a temperature as to 
generate steam bubbles, which rise vertically (it does not matter 
in what position or angle the heating surfaces may be arranged, 
the steam bubbles always ascend in vertical lines), and spread 

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MODERN SYSTEMS OF GENERATING STEAM. 45 

to the right and left, keeping always in contact with the roof 
of the tube, as rapidly as this takes place an undercurrent on 
each side runs in to supply their place ; but the water will be 
very much agitated, and the bubbles fluctuate from end to end 
of the tube. On heating the tube the entire length, the under- 
current disappears, and the contents become a seething mass of 
foam. The reason of this is, that there is no circulation or 
flow of water passing through the tube, and no water surface 
whereon the steam bubbles may break, and this state of things 
causes the metal to overheat. By raising one end of the tube 
so as to throw it into an inclined position, the steam bubbles 
immediately rush to the highest end, and in doing so carry a 
large quantity of water with them. This water endeavours to 
find its way again to the lower end of the tube, and would 
doubtless do so if the issuing steam and water were not driving 
it back ; the result of this is, that the tube is very indifferently 
supplied with water, and the struggle between the ascending 
and attempting descending currents produces foam, the metal 
overheats, and the tubes fail. 

The author, knowing that a difference in the temperatures 
of two volumes of water would produce circulation, attempted 
to separate the currents. The hottest water, owing to its levity 
being the ascending stream, he allowed to pass up an annular 
space, while the cooler or denser water he endeavoured to 
convey to the lower end of the outer tube through an inner 
concentric pipe. But this arrangement proved of no avail, 
as the difference in temperature could not be maintained. 
The reason is, he thinks, that in practice the water or foam in 
the annular space is of sufficient temperature to generate 
steam bubbles in the inner pipe, and the very same action then 
takes place as is going on in the outer tube. This conclusion 
is doubtless correct, as one eminent firm has discarded the use 
of the inner pipe, because the two currents destroyed each 
other. By placing another tube alongside, and connecting the 
ends to the other, so as to form the shape shown in Fig. 4, and 
by applying heat to only one, say A, tne change in the . con- 
tents of the tube is instantaneous. In place of foam and a 
violent agitation of the water there commences a steady flow 
or circulation in the direction of the arrows. For as rapidly 
as the water and steam bubbles rise in the tube A to B the 
return or circulating stream flows through B, down C, through 
D, and enters A at the opposite end from which it issued. In 
this way there is no struggle between the ascending or descend- 
ing currents, as each is carried through a separate tube. The 
generating tube A is constantly supplied at tne lower end with 
dense or cooler water, and overheating of the metal is im- 

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46 MODERN SYSTEMS OF GENERATING STEAM. 

possible, as the circulation commences immediately heat is 
applied. Now if the water line was about midway in the tube 
B the bubbles would break on reaching the water surface and 
the steam pass out at the opening E, the water flowing on as 
before • stated. It will be seen that this is the only true 
principle of obtaining " every facility for the escape of the 
steam and the supply of water to the tubes to prevent over- 
heating." By applying heat to the tubes A and C the circula- 
tion is immediately destroyed, and the very same commotion 
of the contents takes place in each tube as occurs when using 
only one. The cause of this is easily explained when we con- 
sider that on raising the temperature of the water in A and C 
the steam bubbles and water rise in each and meet in the bend 
B. The opposing currents meeting there, produce a violent 
agitation, tne result of which is that the water and steam im- 
mediately commence sputtering out at the opening E, and the 
tubes A and are left with very little water in them. The 
lesson to be learned is that one tube must be kept cool, and on 
no account must heat be applied to the descending current. 
With but one exception this most essential feature has been 
completely overlooked when designing water-tube boilers, and 
the results have consequently been unsatisfactory, and in some 
cases have ended in failure. 

Although we have chiefly considered -horizontal and inclined 
tubes, the same effects to a greater or less extent occur in 
vertical ones. The arguments are based on the former, as that 
arrangement appears preferable, and is generally adopted. In 
the existing types of land and marine boilers which contain a 
large volume of water, circulation is left to take care of itself. 
This brings about unequal temperature of the shell, flues, and 
tubes, which produces unequal expansion of the parts, and 
causes leakage at the seams, rivets, and tube ends. . Moreover, 
it is only the film of water next the plate that receives heat 
and is formed into steam, the remainder being comparatively 
useless, unless brought into contact with the hot metal. It is 
well-known that even with these boilers, if the circulation has 
been improved, they have shown themselves to be more 
economical and durable than others of the same type. Instances 
have come under the writer's notice where heating surface has 
been sacrificed by withdrawing tubes ; but owing to the im- 
proved circulation, these boilers made steam quicker, and were 
not so liable to be damaged by the fire. Where there is a 
continuous flow of water over the hot metal the heating 
surfaces are more effective, as the currents not only wipe off 
the clinging layers of steam bubbles that are in contact with 
the plate, but at the same time bring a steady stream of dense 



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MODERN SYSTEMS OF GENERATING STEAM. 47 

or cooler water to them. In water-tube boilers the volume of 
water is subdivided, and as their heating surfaces are most 
effective and ebullition so general, unless the circulation of the 
water is provided for in the manner before stated we cannot 
expect good results under continual working. 

Thirdly, "They must be so connected that no destructiva 
expansion can take place, which would produce leakage at the 
joints." After the tubes are arranged in the furnace and the 
fires started, those nearest or immediately over the fire will be 
exposed to the highest temperature. The gases will not only 
envelop them, but the radiant heat from the incandescent fuel 
greatly assist in raising the temperature of the metal. The 

Products of combustion will be gradually cooled as they are 
rought in contact with other tubes farther removed from the 
fire, and the heat absorbed as completely as possible before it 
leaves the boiler. It follows that those tubes that are exposed 
to the greatest heat will generate the largest volume of steam, 
and that those in different positions of the boiler will not be at 
the same temperature. This difference in temperature is very 
injurious, and causes leakage, as before stated. If all the 
tubes were raised to the same temperature, they would expand - 
equally ; but this is never the case in practice. When ooth 
ends of the tubes are attached rigidly to others, or to a flat 
surface, it is impossible for them to expand without a risk of 
starting the joints. To counteract the evil effects of unequal 
expansion and contraction various arrangements have teen 
adopted ; the most recent device is the use of smaller curved 
pipes. Owing to their flexibility, these bends will * give and 
take " without any fear of starting joints ; and it will be seen 
farther on that they are also made to contribute in a marked 
degree to the success of the sectional boiler. 

Fourthly, " They must be easily cleaned and examined in- 
ternally and externally, and deposits in the water collected 
in tubes not exposed to heat." One of the greatest difficulties 
steam users have to contend with is the formation of deposit 
and incrustation in their boilers. Where the scale does not 
exceed the thickness of an eggshell, it may in most cases be 
regarded as an advantage, forming, as it does, a coating which 
protects the iron from the corrosive action of the water ; but 
when it accumulates in considerable quantities on the heated 
metal it becomes a source of danger, leads to a wasteful expen- 
diture of fuel, and tends to shorten the life of the boiler. 
Impurities in the water will be precipitated by the application 
of neat, or left behind by evaporation. It is therefore very 
necessary that they should be collected in tubes or other 
receptacles outside the boiler, where they can do no harm, and 

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48 MODERN SYSTEMS OF GENERATING STEAM. 

may be readily blown out If allowed to collect in the gene- 
rating tubes, as is sometimes done, we should only have 
sediment instead of water in contact with the iron. The 
result is that the metal is deteriorated from overheating, and 
the tubes burn out The advantages to be derived from heat- 
ing the feed-water are twofold. In the first place, by increasing 
its temperature before entering the boiler a direct saving in 
fuel is effected, and the metal is not injured by being chilled. 
A rapid circulation of the water through the tubes of the boiler 
tends to scour them, and prevents incrustation. The force of 
the current buoys impurities up, and they settle where the 
water is quiet, which is in the mud collector outside the 
boiler. This is provided with doors or covers, by the occa- 
' sional removal of which the interior of the tubes and other 
parts can be thoroughly cleaned and examined. The necessity 
of keeping the heating surfaces free from soot and other non- 
conducting substances is very important, from the consideration 
of the extremely short time witn which the hot gases are in 
contact with the metal, and the reluctance with which they give 
up their heat. Were these impurities allowed to accumulate, 
the efficacy of the receiving surfaces would be seriously im- 
paired and the fuel uselessly expended. Therefore any simple 
and effective arrangement for preventing smoke is worthy of 
consideration. By increasing the volume of atmospheric air in 
the furnace and maintaining a high temperature therein, the 
presence of smoke may be avoided. In a boiler furnace there 
is always a sufficiently high temperature, unless the furnace is 
choked with fresh fuel, but the supply of air, especially above 
the fire, is too often wanting. Many smoke-preventing ap- 
pliances have failed by the admittance of too much cold air, 
whereby the temperature of the flues has been reduced, and 
the boilers have proved inadequate to generate the necessary 
volume of steam. For the purpose of cleaning the outside of 
the tubes from soot and other non-conducting material, doors 
are arranged in the most convenient parts of the brickwork or 
boiler framing. Through these openings the tubes may be 
scraped and the dust' swept out. In some cases a jet of steam 
has been used for removing these impurities. 

Fifthly, " They should be constructed so that the parts are 
readily disconnected and all joints outside/' There are several 
ways of fulfilling these requirements. Some arrangements 
possess greater advantages than others. The object in all cases 
is to make and keep steam and water-tight joints. A recent ' 

arrangement, shown in Figs. 10 and 11, is as follows: The 
front end of each generating and superheating tube has a i 

wrought-iron flange screwed thereon, the opposite end of each i 



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MODERN SYSTEMS OF GENERATING STEAM. 49 

being provided with an inside flange welded in. To all of these 
a wrought-iron lid or cover is bolted, and into each cover a 
small straight or curved pipe is screwed. The correct length 
or position of this pipe being adjusted, it is secured by a lock* 
nut, or collar. The faces of the flanges and covers are truly 
turned, and the joints made tight with a little paint or a ring 
of copper wire, no inrfiarubber or other perishable packing 
being necessary. By unscrewing the nuts the joints may easily 
be broken ana remade as often as required without difficulty 
and without the necessity of interfering in any way with the 
boiler seating. All joints and connections being outside the 
boiler framing and visible, are not like others destroyed by 
the flame and heated gases, and no secret or destructive leakage 
can take place without being detected. 

Sixthly, " A large water surface should be provided to prevent 
priming ; also sufficient steam and water storage." In dealing 
with this question it will be necessary to explain the advantages 
of a large water surface, and in what manner it prevents 
priming. When speaking of circulation of the water allusion 
was made to the steam bubbles always travelling to the highest 
end of an inclined tube, and rising to the water line befoie 
breaking. It appears that the steam is enveloped by a film of 
water which resembles little globules rapidly rotating on their 
axes. A good illustration is the ordinary soap bubbles blown 
with the aid of a pipe, which on breaking scatter the film of 
water. In the same manner the steam bubbles on reaching the 
water surface burst, and the steam is liberated. Now if the 
water surface is small, these bubbles will be concentrated, and 
in breaking upheave some of the water. The spray passing 
away with the steam is commonly called priming. Should 
sufficient of it enter the cylinder of an engine, the covers may 
be split thereby. The larger the area of tne water surface for 
the bubbles to break upon, the less liability is there to priming. 
In most water-tube boilers the water surface is ridiculously 
small, and no one need be surprised to learn that those are 
" heavy primers." In several boilers of this class the bubbles 
on leaving the generating tubes have some distance to travel, 
and as they ascend increase in size and velocity, so that on 
reaching the water surface they burst with violence and the 
water is uplifted and covered with foam, which is very objec- 
tionable. To endeavour to control the velocity of their ascent, 
some inventors arrange deflecting or baffle plates, or tortuous 
passages, which check the currents. This tne author does not 
approve of, as it is after all only introducing a defect, and then 
trying to correct it. A better plan is to provide a large water 
surface at or near the mouths of the generating tubes, then all 

E 



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50 MODERN SYSTEMS OF GENERATING STEAM. 

such devices will be needless. Another feature that should not 
be overlooked is the necessity of a large steam and water 
storage, the benefits to be derived from the former being a 
more regular supply of steam with less liability to priming. 
For if the steam space is small, and the engine draws away the 
steam as rapidly as it is generated, a great deal of water in the 
form of spray leaves the boiler, which is sometimes credited 
with having evaporated. 

There should always be an excess of steam over that required 
by the engine. A large water storage prevents any sudden 
fluctuation in its level, and should it become low through 
negligence, there is not the same fear of the boiler being 
damaged. The generating tubes when supplied from a reservoir 
of water are better filled, and not so liable to be injured by 
the fire. In most water-tube boilers the upper tier of tubes 
forms part of the steam space, and the steam is generally more 
or less dried or superheated before reaching the steam drum, 
where the stop and safety valves are situated. The advantage 
of superheated steam is, that it can be conveyed to a greater 
distance without condensation, and less waste from this cause 
takes place in the engine cylinder. When using it at sea a 
difficulty has been experienced in keeping the high-pressure 
cylinder properly lubricated. The metal also undergoes some 
change whereby the cast iron is softened and soon wears away. 
At present, the reason of this cannot be accounted for, but a 
remedy has fortunately been found by using cast-steel liners, 
which in practice have given the best possible results. It was 
recently noticed in The Engineer that a high-pressure cylinder 
having a steel liner 32 inches in diameter, after eighteen months 
running, showed not the slightest signs of wear either to piston 
or cylinder. The advantage of substituting these liners will be 
readily appreciated by steamship owners. Their application at 
once removes the greatest impediment to the use of higher 
steam pressures. It is very desirable that any water or spray 
be completely separated from the steam before it enters the 
steam space. To accomplish this the author employs a casing 
called a separator, see Fig. 12, wherein is fixed a perforated 
pipe. The steam on passing through these perforations is 
strained from any water with which it may be impregnated, 
and enters the steam space comparatively dry and ready to be 
superheated. In testing the evaporative efficiency of any gene- 
rator, great care should be exercised that the water with which 
the steam may be saturated be carefully trapped and deducted 
before calculating the results, as in some instances where 
boilers have primed, an error has been introduced in preparing 
the data. 



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MODERN SYSTEMS OF GENERATING STEAM. 51 

Having disposed of the conditions essential to secure satis- 
factory results under continual working, the author will now 
direct attention to two water-tube or sectional boilers, which, 
although differing in design and mode of working, will throw, 
much light on the subject With one of these, viz. the * Mon- 
tana's/ a gigantic experiment at sea was carried out, and, 
although it proved a complete failure, it should not pass 
unnoticed. Much may be learned from this trial, and it is very 
desirable to guard against a similar occurrence, which object 
will be best attained by giving publicity to the design and 
endeavouring to solve the cause of the failure. With this view 
the writer prepared a longitudinal and transverse section, 
Figs. 5 and 6, of one of the boilers from the description that 
appeared in the Nautical Magazine, of November, 1873, and 
though they are far from complete, and small errors have 
doubtless crept in, the general design is in accordance with the 
ipformation that has become public, and is sufficient to form a 
basis for discussion. Extracts from the same article, giving a 
description of the construction of the ' Montana's ' boilers, their 
performance under steam, and the views of the writer as to the 
cause of failure, are as follows : 

" The design was made out for 350 tubes, each 15 feet long 
by 15 inches diameter, made of boiler plate \ inch thick ; the 
tubes welded longitudinally in two lengths, and then butt- 
welded in the middle. The 350 tubes were divided into ten 
equal parts, called ten boilers. Each of these contained thirty- 
five tubes arranged in five horizontal rows, each row con- 
taining seven tubes (four only are seen in transverse section). 
The tubes lay nearly horizontal, there being only 9 inches incli- 
nation in the length, 15 feet. To make a flame-way through 
the stack of tubes, they were arranged, close horizontally, and 
12 inches apart vertically ; the dark line shows the position of 
the fire-bars. The tubes in the same vertical line were joined 
together at the ends by vertical connecting pipes, 6} inches in 
diameter, so that each of the ten boilers was again subdivided 
into eight sections, that over the furnace mouths consisting of 
three tubes joined by the end vertical pipes, to be 4 feet 6 inches 
centre to centre. The remainder contain five tubes in each 
section, at 2 feet 3 inches centres, except the one over the back 
end of the furnaces, which has only two tubes. Each of these 
tubes was in fact a little boiler, equal to about 3 horse-power 
nominal, by the Lancashire rule, six square feet horizontal area 

Ser horse-power. On each of these there were two manhole 
oors, with cross bars and centre bolts. There were, therefore, 
altogether 700 manhole doors on boilers, besides eighty feed- 
pipe, seventy scum-pipe, and eighty steam-pipe connections. 

s 2 

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52 MODERN SYSTEMS OF GENERATING STEAM. 

"Tbe tabes were carried on cast-iron framing below, with 
wrought-iron girders, dividing the flame-way space. These ten 
boilers were placed back to back, five upon each side of the 
centre line of tbe ship, with two stokeholes, one in each wins:, 
each about 80 feet in length. There was no dividing wall 
between the two rows of boilers ; each flame-way was common 
to two opposite furnaces, as is generally the case in the usual 
form of double-ended boilers. Three superheaters, each about 
8 feet in diameter, and about 30 feet in length, are placed, two 
horizontally in the uptake, and one between vertically in the 
funnel, forming an inverted T about 65 feet in horizontal 
length. One immense uptake, 80 feet long, extended from end 
to end of the boilers on the top, and led into one oval funnel. 
The surface of this uptake, more than 1500 square feet, made 
the space above the boilers, where all the steam stop-valves 
were placed, intolerably hot, but the stokeholes were rather 
cooler than with ordinary boilers. The two vertical sections 
nearest the front were set apart as a feed-heater, the feed 
entering at the top ; as it was expected that only heated water 
would leave them, an outlet for that was provided at the 
bottom of each, where they communicated with a large cast- 
iron feed chamber open to all the sections. In this feed-heater 
design there seems to have been two departures from orthodox 
practice. Feed-heaters are usually made to appropriate what 
would otherwise be waste heat. In thirty-eight hours five of the 
ten boilers were disabled, all at the same place, viz. the lower 
tube of the five-tube feed-heater ' section.' At Portsmouth the 
damaged tubes were repaired, and each fivfe-tube feed-heater 
section was connected to the boiler proper, leaving only one 
section, viz. that with three tubes as feed-heater. A large feed 
pipe of cast iron ran across the breadth of the boiler, a little 
below the low end of the lowest tubes; each of the sections 
communicated with this pipe by an open pipe 2£ inches in 
diameter. On the top at the high end a smaller pipe for steam 
ran across the whole breadth of the boiler, and communicated 

with each section by an open pipe 2 inches in diameter 

Evidently that section which made most steam would require 
most water, but the very fact of there being most steam made 
in it would cause the pressure of the steam to be higher in that 
section than in the others, and would blow the water out, 
making the water level lowest in that section which had the 
best heating surface." 

The author does not endorse this view as to the cause of the 
failure of the tubes, neither does he agree with the remedy 
suggested. He is well aware that if two distinct boilers are 
connected by a common pipe through which water may pass 

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MODERN SYSTEMS OF GENERATING STEAM. 53 

from one to the other, there should also be provided a similar 
steam connection. In ordinary boilers it may occur that when 
the fires are being cleaned and the temperature of the flues, &c, 
reduced by the excess of cold air passing through the open 
doors, or from some other cause the steam pressure is lowered 
in that boiler, there is a danger of the water being forced from 
another into the one haying the reduced pressure. But on 
inspecting the transverse section, Fig. 6, it will be noticed by 
the arrows that the flame and heated gases act quite as favour- 
ably upon one section as upon another. If the temperature of 
the furnace is increased, then all the sections generate more 
steam ; if, on the contrary, it is lowered, the efficiency of all is 
correspondingly impaired, and on looking at the bottom tubes 
it would be difficult to say which one would generate most 
steam, or soonest boil dry, or from which section the water would 
be blown out, or which would receive it. There is no doubt 
that the tubes failed from overheating caused by shortness of 
water. The author will endeavour to state his views as to the 
cause of their failure. In so doing, he will direct attention to 
the longitudinal section, Fig. 5, from which it will be seen that 
the highest ends of the inclined tubes A are connected by 
vertical neck-pieces B, while the lower ends are similarly con- 
nected by the tubes D. The highest connecting pieces B and D 
communicate with the inclined tube C. 

It would appear at first sight from this arrangement that the 
circulation of the water is good, and that all the tubes A are 
continually supplied at their lower ends. On the temperature 
of the water being increased in A, owing to its levity it would 
travel to the high ends of the tubes, entering and passing 
through the connecting pieces B, into C, running down C, and 
flowing through D, and thus supplying the lower ends of 
tubes A. If this really took place, now was it that the tubes A 
were deficient of water ? Two reasons suggest themselves. The 
first is that the return or descending currents of water were 
impeded and driven back in the following manner, viz. : That 
the tubes and connecting pieces D being exposed to the flame 
and heated gases, steam would therefore be generated in them, 
which would instantly rush up the pipes D, and in doing so 
carry a quantity of water with it. On entering the lower end 
of the tube C, this opposing current from the tubes D would be 
further strengthened by any steam that might be generated in 
the tube C ; these combining would endeavour to travel to the 
highest end of the tubes ; but here would meet in its very 
teeth the currents of steam and water flowing up from the 
tubes B. Two currents of steam and water meeting face to 
face, produce a violent agitation in the tube 0, the contents 

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51 MODERN SYSTEMS OF GENERATING STEAM. 

soon become a seething mass of foam, and the water surface is 
at once destroyed. Doubtless owing to this, much of the water 
left the boiler by passing out at the steam pipe F, and entered 
the superheater. It may be said that the products of combus- 
tion were cooled before reaching the tuoes 0, therefore no 
steam could be generated in tbem. This is not the case in 
practice, for if the temperature of the escaping gases is higher 
(which it always is) than the temperature of the steam, some 
water in the tubes will be converted into steam. It is certain 
that the neck-pieces D, owing to their positions, presented most 
effective heating surfaces, and that a considerable quantity of 
steam was generated in them. 

The second reason is that there was nothing to ensure that 
each of the tubes A received its proper share of the circulating 
water. Even presuming that in spite of this meeting of 
opposing currents in the tubes water did enter the uppermost 
neck-piece D, how much of it would pass into the lowest 
tube A ? Surely very little. For to reach it the descending 
current would have to pass through four of the neck-pieces and 
across three tubes; ana when we consider that the area of the 
uppermost connecting piece D had to supply all the tubes, and 
that the upward rush of steam and water through them is 
always opposing the descending stream, it is very probable that 
most of the water that passed through the uppermost neck D 
entered the tubes A nearest it The lowest tube being farthest 
away from the return or circulating current, obtained very little 
water when it ought to have received a full supply, or far more 
than any of the others ; for it was not only exposed to the 
highest temperature of the furnace gases, but also to the radiant 
heat from the incandescent fuel, and it is therefore not surprising 
that the lowest tubes soon came to grief from the overheating of 
the metal. The mistake appears to have been this — that all the 
tubes A entirely depended upon the uppermost connecting 
piece D for their supply of water, and there was nothing to 
ensure how much entered any particular tube, or how more 
water could be directed to that tube that was exposed to the 
highest temperature, and generated the largest volume of steam. 
As the water that entered them was more or less in a state of 
foam it was not in such good condition for keeping the metal 
cool ; therefore it will easily be seen that " every facility was 
not provided for the escape of steam and supply of water to the 
tubes to prevent overheating." Possibly the feed entering at 
E assisted in supplying the lowest tube, and prevented its 
speedy destruction ; but, on the other hand, this cool water 
was very apt to chill the overheated iron, and cause it to crack. 
The pipe F for the escape of the steam generated in an entire 



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MODERN SYSTEMS OF GENERATING STEAM. 55 

section was exceedingly small. These numerous defects conw 
bined brought the trial to an unsatisfactory termination, which 
resulted in the removal of the boilers. 

The author having given much attention to the subject, and 
having had considerable experience in the construction and 
working of modern stationary and marine boilers, he designed 
the generator shown in Figs. 7, 8, and 9, and which he proposes 
to bring next under notice. It is a sectional boiler, of which 
Fig. 7 is a longitudinal section, Figs. 8 and 9 being respectively 
a front and back elevation. It is composed of a series of hori- 
zontally inclined generating tubes A, arranged over the furnace 
so as to break joint, the alternate rows of tubes being placed 
immediately over the spaces left between those beneath them ; 
in this manner they present the most favourable heating sur- 
faces to the flame and heated gases as they travel in a zigzag 
course to the stack or funnel. The flame-way is divided by 
division plates H, which not only retard the escape of the pro- 
ducts of combustion, thereby affording sufficient time for the 
absorption of heat, but also allow a longer run for the heated 
gases, and by their adoption a more uniform diffusion of heat 
is secured over the entire length of the tubes. The front or 
higher ends of the inclined tubes are provided with heavy 
wrought-iron flanges screwed firmly thereon. The back or 
lower ends have a wrought-iron ring welded in. To each flange 
and ring a wrought-iron cover is secured by numerous bolts. 
Screwed into these covers are the small straight or curved pipes 
which communicate at the back end with the large outside 
pipe D, and at the front with a similar one marked B. The 
pipes B and D are connected by the large outside circulating 
or return pipe C — shown partly in dotted lines in the longi- 
tudinal section, Fig. 7 — which conveys the dense or cooler water 
in an uninterrupted stream from the pipe B back to the pipe D, 
the latter constantly supplying the lower ends of the generating 
tubes A with a large volume of water, which, on becoming 
heated, travels with any steam bubbles generated in them to 
the high end of the inclined tubes and enters the pipe B, where 
the steam bubbles have the advantage of a large water service 
for the liberation of the steam. The water that enters the 
large pipe B flows to the end of it, runs down the circulating 
pipe C, enters and fills the pipe D, with which the lowest ends 
of all the tubes A communicate, these being supplied with 
water as rapidly as it escapes from the highest end. This con- 
stant circulation prevents the water surface in the pipe B from 
being destroyed, as the circulating pipe C conveys the water 
away as rapidly as it enters. The generating tubes being 
supplied from a reservoir of water in the pipe D, are better 

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56 MODERN SYSTEMS OF GENERATING STEAM. 

filled, thereby removing all danger of the overheating of the 
metal. 

It will be noticed that each tube is quite distinct, and draws 
direct from its source of supply ; therefore the steam and water 
communications are in no way dependent upon those around it. 
This was not the case with the ' Montana's ' Tboilers. The circu- 
lation of the water commences immediately the fires are started: 
those tubes that are nearest the fire, and generate the largest 
quantity of steam, will have the most rapid flow of water passing 
through them, as the rapidity of the current is always in pro- 
portion to the heat applied. This also prevents deposits accu- 
mulating in the tubes exposed to heat. The steam on leaving 
the large pipe B passes through separators E, where it is 
separated from any water with which it is saturated, and enters 
the uppermost tubes comparatively dry. The upper tubes F 
are connected in such a manner that the steam in passing 
through them is moderately superheated before reaching the 
steam drum 6, where the stop and safety valves are situated. The 
small curved pipes are attached to the under side of the pipe B, 
the upward currents of water from them buoy the sediment up 
and prevent it settliug ; it therefore passes away with the cir- 
culating water and settles in the pipe D at the back of the 
boiler, where it does no harm, and may be blown out as 
frequently as desired. The curved pipes at the back being 
connected at the top of the pipe D, leave the water therein 
undisturbed, and from their position they cannot be choked by 
any sediment that may.be collected in the large pipe. 

An important feature is that no Joint or connection is in the 
furnace or facing it, all being outside the boiler framing visible 
and easily got at. No secret leakage can occur, neither are the 
joints injured by the flame and heated gases. All the connec- 
tions are exceedingly simple, the flanges being truly faced and 
the joints made tight with a ring of copper wire or a little 
paint. In the event of disconnecting any part for cleaning, 
inspection, or repairs, all that is required is the removal of the 
nuts, which is accomplished by the aid of a spanner. Any 
tube can then be withdrawn and another inserted ; or, in the 
event of one not being ready, a blank flange or cover may be 
fitted over the openings, and the boiler worked with the same 
certainty as before, as the steam and water communications to 
each tube are quite distinct, and in no way dependent upon 
those around it. Every part is made on the interchangeable 
system, and duplicates of each other. The tubes when required 
may be turned, exchanged, brought nearer to or placed farther 
from the fire, which greatly conduces to the long life of the 
boiler. Not only does the entire arrangement produce a 



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MODERN SYSTEMS OF GENERATING STEAM. 57 

flexible system, but any tub9, on account of the elasticity of 
the carved pipes, will expand or contract without fear of start* 
ing the joints, no indiarubber or other perishable material being 
necessary. This boiler is also provided with a larger volume 
of water than most sectional boilers, which prevents any sudden 
fluctuation in its level, and reduces the danger of the over- 
heating of the metal through shortness of water. The outside 
pipes and connections, not being exposed to the heat or subject 
to the varying temperature of the furnace, are not injured 
by inequality of temperature or wasted thereby. They are all 
carefully protected oy non-conducting composition, or some 
other improved method to prevent radiation of heat, the joints 
and bolts being left exposed for inspection or for disconnecting. 
No heat being applied to the returning stream of water in the 
pipes B, C, and I), the circulation is not interfered with, as no 
steam is generated in them. The tubes are supported at each 
end by an iron framing lined with fire-clay, the sides enclosed 
by two short parallel Tbrick walls, or by an iron casing having 
air spaces. It will be, noticed that the fire-grate is not restricted ; 
an immense area, far greater than is ever required, can be 
obtained without trouble. There is also ample space for the 
thorough mixing of the gases with atmospheric air, thus 
ensuring complete combustion before the flame aud hot gases 
are brought in contact with the heating surfaces of the tubes. 
Owing to the efficacy of the surfaces, and the long run provided 
for the products of combustion, the heat from the furnace is 
absorbed as far as possible by the generating tubes A before it 
reaches the uppermost tier; these tubes are therefore not 
injured by the escaping gases, but when desired they may be 
dispensed with and the steam led direct from the separators 
into the steam drum. In the larger sizes of boilers a circu- 
lating pipe is connected to each end of the pipes B and D. The 
power of the boiler may be increased by adding more tubes to 
the sides, or by arranging additional tubes over the present 
ones. Suitable openings are provided in any convenient part 
of the brickwork or boiler framing for cleaning the outside of 
the tubes from soot, &a, with a steam jet or otherwise ; and 
where the width for fixing the boiler is restricted, the outside 
circulating pipe C may be made to rest in a U shape casting 
built in the wall ; the mouth of this casting opening outwards 
allows the pipe C to be removed when necessary. 

It is an established fact that sectional boilers possess impor- 
tant facilities for exportation. Owing to the small size and 
weight of their parts they are well adapted for shipment and 
transit over mountainous countries, no special conveyance being 
necessary. They occupy smaller space, and may be fixed where 

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58 MODERN SYSTEMS OF GENERATING STEAM. 

it would prove impossible to erect one of another type. The 
tubes and other portions can be carried through a narrow door- 
way without disturbing existing premises, and the parts easily 
handled and connected. A few months ago the writer was 
requested to estimate for an 80 horse-power nominal marine 
boiler, but declined, it being impossible to complete and fix it 
in the specified time. This was to be regretted, as such an 
excellent opportunity for establishing the reliability of water- 
tube boilers at sea might seldom occur. The steamship that 
required it was deficient of steam power, which brought about 
a corresponding reduction in the speed of the vessel, owing to 
the pressure having been gradually reduced on account of the 
deterioration of the boilers. The ship was compelled to go 
round to Glasgow, where her decks were opened up, and an 
auxiliary boiler of the ordinary construction placed in the stoke- 
hole. She then returned to London, and commenced taking in 
cargo. The loss of time and great expense incurred in steam- 
ing to and from Glasgow, and while there, was calculated at 
not less than 6001. If a sectional boiler had been adopted this 
expense and loss of time might have been avoided ; as the tubes, 
casing, &c, would have been lowered into the stokehole without 
interfering with decks or other portions of the vessel, and put 
together in the place where it was intended to work. This 
could have been done while in London, as no powerful crane 
was necessary. 

These are very important advantages peculiar to sectional 
boilers. When adopted for marine use, orickwork would be 
dispensed with, and the sides enclosed by an iron casing having 
air spaces. This casing not only saves weight and space, but 
keeps the stokehole cooler. An objection is sometimes raised 

Xinst water-tube generators, to the effect that they are com- 
ated and have so many joints. In breaking up a marine, 
>comotive, or portable boiler, and collecting all the parts neces- 
sary for its construction, no one would be struck with the idea 
of simplicity. They appear simple when seen from the outside, 
solely because most of the parts are inside and hidden from 
view. But then there are joints at each end of the tubes, seams, 
rivets, &c, to keep tight. In sectional boilers no seams, angle 
irons, or rivets are necessary, and all joints being outside makes 
them at first sight appear complicated. These, however; if 
properly made, can be kept tight without trouble, even when 
working at a very high pressure, and the facility with which the 
parts can be disconnected for examination, repairs, or cleaning, 
should recommend them. Although the boilers of the steam- 
ship ' Montana ' had 700 manhole doors, besides other connections, 
there appears not to have been the slightest difficulty in keep- 
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MODERN SYSTEMS OF GENERATING STEAM. 59 

ing them perfectly tight, Dot withstanding the severe test pro- 
duced by the overheating of the tubes. 

No allusion has before been made to the great advantages 
of the principle of subdivided shells as regards safety from 
disastrous explosion. In no instance with them has the writer 
heard of any destruction to property. A few accidents have 
occurred — the result of a defective joint or tube — whereby lives 
have been sacrificed by the outrush of boiling water and steam ; 
but the boiler and seating always remained intact. So these 
mishaps cannot be called explosions in the sense in which the 
word is generally applied, flow different the effects when an 
explosion takes place with the land and marine boilers in 
common use ! With them the loss] of life is dreadful, the de- 
struction to property immense, entire buildings demolished in an 
instant, the wreck of the property in many cases burying in its 
fall those that are near. The fact of the parts of these boilers 
being propelled like a rocket, and sometimes thrown to a great 
distance, best testifies to their destructive qualities. These 
accidents so very frequently occur, that it appears the best 
materials, workmanship, and most careful inspection by com- 
petent engineers fail to put an end to them. The safety of 
ordinary boilers depends upon so many contingencies, the 
margin of security is so small, and there are so many defects 
that defy detection, that with the best of them absolute security 
from destructive explosions cannot be relied upon. By substi- 
tuting a good sectional boiler in preference to the dangerous 
types in general use, these accidents may be prevented with a 
gain as to efficiency and economy. In conclusion, the author is 
convinced that if water-tube boilers are carefully designed to 
meet the conditions herein stated, and rightly proportioned for 
the work they are to perform, the best possible results may be. 
relied upon, and they will prove their superiority under con- 
tinual working. 



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( 60 ) 



June lirf, 1874. 

WILLIAM MACGEORGE, President, in the Chair. 

MODERN SYSTEMS OF GENERATING STEAM. 

ADJOUBNED DISCUSSION. 

Mr. Vaughan Pendred opened the discussion by reading 
the following communication : 

In opening the discussion on Mr. Suckling's paper, I would 
first direct attention to the vital importance of the issues raised 
by the author. In the autumn of 1867, I had the honour of 
reading a paper on water-tube boilers before this Society, and 
the subject of that paper attracted much attention. Water-tube 
boilers were then comparatively new things, but such is not the 
case now, and we find that many efforts have been made of late 
years, and with varied success, to bring the system to perfection. 
That success will ultimately attend the labours of inventors in 
this field, I do not doubt, because with high-pressure steam we 
must resort to the use of boilers of small diameter. The Black- 
burn explosion has done much to convince millowners and 
others that high pressures cannot be carried as successfully in 
large Lancashire or Cornish boilers as is desirable, and it is, I 
think, fortunate that such boilers present no special advantages 
which can render their continued use essential. They have, on 
the contrary, three defects of great importance : First, they are 
weak ; secondly, they are costly ; and thirdly, they are inacces- 
sible for examination, cleaning, and repairs. Nor can they lay 
any claim to be considered exceptionally economical in the 
matter of fuel. It would seem, therefore, that there is plenty 
of room for the introduction of another type of boiler, such, for 
example, as that of Mr. Suckling. 

I shall not attempt to criticise or point out the advantages 
and defects of the numerous novel types of boiler now before 
the public. That can best be done by those who have invented, 
tested, and practically used those boilers. It will rather be 
my object to call attention to one or two points connected with 
the generation of steam, and one or two phenomena which 
Mr. Suckling has either not referred to at ail, or, at least, not 
so fully as could be desired. You will find on perusing the 
paper that Mr. Suckling has left much connected with the 
working of steam boilers untouched, and as we are all interested 



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MODERN SYSTEMS OF GENERATING STEAM. 61 

in the manufacture of steam, it will not, I think, be out of place 
to call attention to those points on which Mr. Suckling has been 
almost silent In a word, I shall endeavour to glance briefly 
at the whole process of making steam, and to point out some of 
the laws and principles which appear to me to be constantly 
neglected, and which it should be one of the functions of this 
and kindred societies to see observed. 

Fuel has become so dear, that economy in its use is of 
the utmost importance. It is impossible, however, to secure 
economy of fuel if the fuel is not properly burned. It will be 
worth while to devote a few moments to a consideration of the 
work which the apparatus, commonly known as a steam boiler, 
has to perform. It is very generally assumed that a " boiler " 
is simply a vessel which will hold hot water under pressure. 
But it is really a very complex apparatus, even in its simplest 
form. For example, a Cornish, or double-flue, boiler includes 
within its shell an apparatus for making gas, for burning gas, 
for burning' carbon, for heating air, for cooling air, for boiling 
water, and for supplying steam ; and if this apparatus does not 
make gas properly, does not burn it to advantage, does not heat 
air economically, does not cool air effectually, does not boil water 
with rapidity, and supply steam of good quality, then it fails to 
discharge its duty properly. And what is true of Cornish 
boilers is true of all boilers. Gentlemen, the word " boiler " is 
a misnomer ; " steam generator " is a misnomer. The title at once 
simple and expressive has yet to be invented, which will define 
the complex operations performed by the apparatus which we 
use in the generation of steam. 

All improvements in the construction of boilers should be 
directed to the attainment of the following objects: First, 
perfect combustion; secondly, perfect absorption of heat; 
thirdly, the production of dry clean steam; fourthly, perfect 
.safety ; fifthly, durability or, in other words, small cost of main- 
tenance ; and sixthly, moderation in first cost. It will be seen 
that no mention is made in this list of economy of fuel. That 
is directly implied by the first two conditions. If, in other words, 
the combustion of the fuel and the absorption of heat be perfect, 
then will the boiler evaporate the largest possible quantity of 
water with the smallest possible quantity of coal. Many new 
boilers have been brought before the public which have com- 
pletely failed, not because the general idea was wrong, but 
because in practice it was impossible to secure proper combus- 
tion of the fuel on the grate, apd some water-tube boilers have 
been great sinners in this respect The idea of the inventor 
was to snap up every particle of heat the moment it was pro- 
duced. The consequence was smoke and waste of fuel. Some 

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62 MODERN SYSTEMS OF GENERATING STEAM. 

of our marine boilers with small furnaces are very uneconomical 
for this and for no other reason. It appears to me, therefore, 
that if Mr. Suckling or any other inventor of a water-tube boiler 
can secure plenty of furnace room he will obtain a very great 
advantage indeed ; and judging from Mr. Suckling's diagrams, 
I think that in this respect he is successful, having provided 
plenty of furnace room. And I fancy that the same thing may 
be said of most of the water-tube boilers now before the public, 
such as Boots/ Howard's, &c. It may be taken, therefore, that 
in regard to furnace room, at all events, water-tube boilers are 
very favourable in their principle of action to combustion. Coal 
ought to be burned to more advantage, and with less difficulty, 
as regards the admission of air in proper quantity above the 
grate, than in almost any other form of boiler. 

Perfect combustion is so essential to the success of any 
boiler which claims to take high economical rank, that, with 
your permission, I shall say a few words now on this subject. 
First, then, it is a very commonly received opinion, that if 
we will but supply air enough to the coal burning in a steam- 
boiler furnace, the combustion must be perfect. It is possible 
that this may, in a certain sense, be true, but it is not true in 
the proper sense. Combustion may be quite perfect, whether 
it is conducted at a very slow or at a very rapid rate. It is 
only necessary to bring precisely the proper quantity of oxygen 
in contact with the proper quantity of carbon or hydrogen to 
satisfy the necessary conditions ; but something more than this 
is required in the generation of steam. The rate of combustion 
may be so slow that the boiler has little or no efficiency, or it 
may be so fast that the plates and tubes are destroyed. Every 
type of boiler appears to have a certain rate of combustion at 
which it will steam better and more economically than at any 
other. Thus locomotive boilers with long and small tubes 
really require a sharp draught and rapid combustion to make 
them economical and efficient. Marine boilers with larger and 
shorter tubes will not give the best results unless coal is burned 
at a much slower rate on their grates than is admissible in the 
case of a locomotiva Stationary boilers of the Cornish type 
require a still slower rate to bring out their best points, feut 
whether the rate of combustion be slow or fast, combustion 
should in all cases be perfect in the sense that the union of the 
combustible, be it solid carbon, or a gas, with oxygen, shall 
be effected with the least possible admission of cold air. 

There is reason to believe that there are some hundreds of 
special devices recorded in the patent offices of this and other 
countries for the prevention of smoke, but about these I will say 
little or nothing. To prevent smoke it is necessary that a 

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MODERN SYSTEMS OF GENERATING STEAM. 63 

moderate quantity of air should be admitted above the fire ; 
and any apparatus which will admit the proper quantity at the 
proper time, and in the proper place, will be satisfactory, 
provided it is simple and not likely to get out of order. 

It is somewhat remarkable that until a very recent date 
little or no attention has been paid to a most important means 
of economizing fuel, and rendering its combustion perfect. I 
allude to the use of heated air for maintaining combustion 
instead of cold air. It is true that many patents have been 
taken out for inventions intended to supply heated air oyer the 
fire, or at the back of the bridge, to consume smoke or prevent 
it, but little or nothing has been done in the way of supplying 
the fuel on the grate with nothing but hot air. Attention is, 
however, now being directed to the subject, and it is probable 
that before long much will be done to effect this desirable 
object. So far, attempts in this direction have been tolerably 
closely confined to the combustion of fuel in iron furnaces, but 
what applies to the combustion of fuel in one case, will gene* 
rally apply in another. The matter is too important, indeed, 
to be passed oyer in silence, and it will be well to explain why 
economy can be secured by heating the air before it enters the 
furnace,* as briefly as is consistent with lucidity. 

Avoiding chemical dissertations, it may be stated, shortly, that 
the smallest quantity of air which will suffice to burn 1 lb. 
of coal is 12 lb. ; that the maximum quantity which should be 
admitted to a steam-boiler furnace is 24 lb. ; and that, in the 
best practice, the quantity is somewhere about 18 lb. Let us 
accept 18 lb. as the required quantity, for the sake of illus- 
tration. Thus, 18 lb. of air is raised in the furnace to a 
temperature of from 2000° to 3000° Fahr. With this tem- 
perature we have, however, for the moment, nothing to do, 
because the air is cooled down again in passing through the 
boiler flues. But as air escapes from the flues at a variable 
temperature, 600° may be taken as a fair average. If the air 
is suffered to escape thus heated, it will run away with a great 
deal of fuel. Let us see how much. A British unit of heat is 
the quantity required to raise one pound of water one degree 
Fahr. The quantity of heat required to raise one pound of air 
one degree Fahr. is '238 unit. The quantity of heat required to 
raise one pound of water to a temperature of 600° is 600 units. 
The quantity of heat required to raise one pound of air to a 
temperature of 600° is 600 X -238 = 142 8, say 143 unite. 
To elevate 18 lb. of air from Zero to 600° will therefore absorb 
143 x 18 = 2574 units. The temperature of stokeholes is 
always high. Let us assume that the air enters the furnace at 
74°, and escapes up the chimney at 600° ; then, for every pound 

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64 MODERN SYSTEMS OF GENERATING STEAM. 

of coal burned, 2500 units of heat are wasted and lost in heating 
the air. 

To convert one pound of water into steam of 75 lb. absolute 
pressure, the water already having a temperature, to begin with, 
of 278°, we must supply 897 ' 5 units of heat But 18 lb. of air 

heated to 600° represents 2500 units, and 8Q? = 2 '78 nearly. 

In other words, the loss due to the escape of the products of 
combustion at 600° represents a loss of evaporative efficiency of, 
broadly speaking, 2| lb. of steam per pound of coal. A Cornish 
boiler supplying 7 lb. of steam per pound of coal burned, 
would, if this loss could be avoided, supply 9 j lb. To put the 
matter in another point of view, each pound of coal burned, or, 
more strictly, each pound of carbon, liberates 14,500 units of 
heat, which would suffice, if it could be all used to effect, to 
evaporate about 15 lb. of water, and the loss of heat incurred by 
the escape of the products of combustion at 600° is therefore 
more than one-sixtn of the whole heat produced. 

Under these conditions, it appears to be highly desirable that 
some attempt should be made to avoid this loss. One plan 
consists in heating the air before it enters the furnace; the 
second consists in introducing, feed-water heaters below the 
Btack and the flues ; and the third plan consists in giving the 
boiler itself so much absorbing surface that the temperature of 
the gas will be reduced to that of the water. I shall not attempt 
to describe any of the systems adopted for heating air. Indeed, 
I feel that I have already digressed somewhat from the subject 
in hand. But I am certain that water-tube boilers, when they 
come into extended use, will be accompanied by the use of hot 
air, and various other devices for securing economy, which are, 
to a great extent, inapplicable to the old style of boiler, and I 
think this is a great point in their favour. 

I will now consider, very shortly, some of the phenomena con- 
nected with the generation of bteam in small tubes. I may 
state that during the last three years I have carried out many 
experiments on the subject, and the statements which I am 
about to make may be regarded as quite accurate. Mr. Suck- 
ling has very clearly laid down some of the conditions essential 
to success in water-tube boilers, but there are a few errors, more 
of omission than of commission, in his statements. 

The first essential in a water-tube boiler is good circulation. 
Now, it is commonly considered that, although circulation may 
be bad in a boiler until steam is up, the ascending rush of steam 
will carry the water before it, and create circulation. This is 
simply a delusion. There are cases in which circulation is 
-caused by a rush of steam, but it is not so in an entire boiler in 

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MODERN SYSTEMS OF GENERATING STEAM. 



65 



any case. The bubbles of steam rise, it is true, but they do not 
rise from any desire of their own to rise, but simply because 
they are lighter than the water, and buoyed up by it. I have 
heard it argued that there must be good circulation in such a 
tube as this : 




because the leg B being filled with rising particles of steam, the 
water in it will be lighter than in A, and so will rise. It would 
be as well to argue that if B were filled with corks the water 
would rise because the column in that side would be lighter 
than in the other. The only thing that can secure efficient 
circulation in a boiler is difference in temperature of two 
columns of water; and many boilers which have a capital 
circulation while the water is being heated, have hardly any 
circulation when ebullition commences. Now, this fact bears 
very powerfully on Mr. Suckling's boiler. The return flow-pipe 
is cooled down, and is slightly heavier than the water in the 
rising pipe ; and if Mr. Suckling is wise, he will always leave 
that pipe unlagged and open to the air. 

If attention is paid to the principle of always allowing the 
heated water to ascend, and cold water to descend, efficient 
circulation can be always secured. As an example, I have 
here a glass model of a boiler tube, which is, I believe, quite 
novel. Hitherto it has been considered quite difficult enough 
to get circulation in one direction in a tube. In this case two 
opposite currents flow through the tube, always entering below, 
and as the water and steam rise they are u sere wed to the 
other end by the helical diaphragm traversing the tube, and 
thus a perfect circulation is secured. The presence of steam is 
the great enemy of circulation in small tubes, as I have found 
over and over again. 

Before concluding, I would direct your attention to what may 
be regarded as a curiosity in steam engineering, I allude to the 
straw-burning portable engine of Messrs. Head and Schemioth. 
A very few years since it would have been said to raise steam 



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66 MODERN SYSTEMS OF GENERATING STEAM. 

with straw was impossible. The apparatus consists of a pair of 
toothed rollers fitted with malleable teeth, and connected with 
the engine by means Qf a pulley driven by a strap from the 
crank shaft. These rollers make forty-eight revolutions per 
minute, and can be turned by hand when getting up steam. 
Movable sliding knives forming a rake are attached to a cross 
bar, and slide on guides, below the grate. This rake can be 
moved with a forward and side motion by the stoker by means 
of a handle, thus breaking up the silieious crust deposited on 
the grate bars, while a perforated pipe is provided for injecting 
water upon the burning ashes. A shoot carries any small pieces 
of ignited straw back into the ash pan, and a wooden trough 
contains the straw which is to be fed into the furnace, and 
which can be removed when the engine is travelling. The 
whole apparatus swings on a hinge and can be taken off in a 
few minutes, and the ordinary fire-door substituted when coal or 
wood is burned. These engines are now at work in large 
numbers, and many leading firms of agricultural engineers 
make them. . I have heard it said that water-tube boilers can 
never be made to succeed. I think with such an example as 
that before us of what engineers can do when they are put to it, 
we may yet hope that water-tube boilers will obtain the favour 
the principle deserves. 

Mr. J. H alliday, of Manchester, exhibited a model of Griffith's 
sectional boiler, which he described. He said that the peculiar 
features of the boiler were, that it was constructed with neating 
tubes, water chambers, and passages so arranged that there was 
a continuous circulation of the water through them during the 
working of the boiler. The ends of the tubes were connected 
with each other by heads of peculiar construction. The heads 
formed the means whereby the tubes communicated through 
straight vertical passages with the water chambers over them. 
Above the water chambers were steam chambers, each of which 
had a separate connection with the water chambers. The 
latter were provided with blow-off cocks or valves for ejecting 
the scum and other foul substances. The lower row of neating 
tubes was connected with a transverse tube which had a blow- 
off cock at one end, and the vertical passages or circulation 
tubes at the rear of the boiler were provided with 'valves for 
closing the vertical passages and reversing the circulation of 
the water in the boiler when the blow-off valves were opened. 
The most beneficial action of the heat upon the tubes was 
obtained by brickwork deflectors, or division walls, erected 
between the tubes and constructed of peculiarly shaped bricks. 
It would be seen that the water would circulate longitudinally 
through the tubes, water chambers, and vertical pipes, and that 

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MODEBN SYSTEMS OF GENERATING STEAM. 67 

it would also circulate horizontally or transversely through the 
heads to or from any of the tubes. 

The steam chambers were placed transversely over the water 
chambers, and each had a separate communication with the 
opposite ends of the water chambers by flanged pieces which 
rested upon and were secured to saddles on the water chambers, 
and whose upper flanges received and supported the steam 
chambers. Each of the steam chambers was provided with a 
branch piece fitted with a safety valve ; the branch pieces were 
connected by a pipe, in the centre of which was placed a stop 
valve whereby steam was taken from the boiler. By having 
that valve arranged midway between the two steam chambers, 
the escape of water with the steam was prevented, as any water 
passing through the pipe in one direction would be driven back 
by the pressure of steam in the opposite direction. The water 
chambers were supported upon girders whose ends rested on 
the columns outside the brickwork setting. The entire upper 
structure of the boiler was thus supported quite independently 
of the tubes and their connections, and the expansion and con- 
traction of any part would not affect the other parts of the boiler. 
The water chambers were provided at the rear end with man- 
holes fitted with covers. 

Mr. Willsher asked how the joints were made. 

Mr. Halliday said that they were chased in the lathe. The 
evaporation of the boiler had not yet been fairly tested. 

Mr. Pendbed asked how the boiler would compare in cost 
with an ordinary Cornish boiler surface for surface. 

Mr. Halliday replied that its cost was considerably heavier 
than that of the Cornish boiler. The cost for a 60 horse-power 
boiler was 101. per horse-power. He regulated the power by 
allowing 16 square feet of total heating surface per horse-power. 
That was the total surface which was exposed to gases. The 
brickwork setting of this boiler would cost about 501. or 607., 
which was less than that of a Cornish boiler. A 60 horse 
boiler fitted complete would cost perhaps 1502. more than a 
Lancashire or Cornish boiler. 

Mr. Pendbed said that that would be about 30 per cent, 
more. The setting was a very important thing, and if a saving 
could be effected in it, it was fair to credit it in favour of the 
cost of the boiler. 

The President asked how many of Mr. Halliday's boilers 
were in use. 

Mr. Halliday said that he had only five in use. It was 
represented that in the United States there were in use boilers 
of this kind to the extent of 250,000 horse-power. In this 
country they had been in use from October, 1872. 

f 2 

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68 MODERN SY8TEM8 OF GENERATING STEAM. 

Mr. Pendred asked what the boiler would evaporate per 16 
square feet of surface if fairly fired. 

Mr. Halliday said that he had* been told that the test 
showed ail evaporation of 10 lb. of water per lb. of coal. He 
had no proper test as to the evaporation per square foot of 
surface, but expected to be able to test it in a few weeks. 

Mr. Pendred said that the proportion of the evaporation 
to the area of the surface was an important consideration in 
putting down a boiler. The term " horse-power " was a very 
vague one. It appeared to him that under certain circum- 
stances they could afford to pay an increased price for a square 
foot of heating surface, for the efficiency of every boiler, after 
all, might be reduced, in one sense, to the question of how 
many square feet of heating surface it contained. If one boiler 
would evaporate only 5 lb. of water per square foot, and another 
would evaporate 10 lb., other things being equal, they could 
afford to pay for the latter twice the price of the former, 
because the latter would do twice the work. 

Mr. F. E. Houghton said that he did not agree with Mr. 
Pendred's remark that the Blackburn explosion had anything 
at all to do with the working of this description of boiler, viz. 
Lancashire, at such high pressure of steam. Both these boilers 
were quite capable of working at a very high pressure. His 
experience had made him rather sceptical of tubular boilers. 
This was in consequence of the large number of them which 
had been patented during the last eighteen years, none of which 
get nigh perfection. The great evil of such boilers was the 
multiplication of parts, and this was particularly objectionable 
when bad water was used. No boiler worked so well with bad 
water as the Lancashire boiler, nor was there one which would 
equal it in the amount of evaporation which could be obtained 
from a pound of coal. Any boiler which would evaporate 9 lb. 
of water with 1 lb. of coal of moderate quality was, in his opinion, 
a good boiler ; and he had yet to see a boiler which would 
evaporate 10 lb. with common firing. Of tubular boilers he 
had had very little experience, except in portable engines, and 
these had given an immense amount of trouble, 7 lb. of water 
was nearer their evaporation than 10 lb. He believed there 
was rio better boiler than the Lancashire. They had stood their 
ground, and were still in requisition on all large works. 

Mr. Pendred said that there was a large margin to be 
allowed in the description of what a Lancashire boiler was. 
The term was commonly applied to a boiler with two flues and 
a fire in the flues. The only difference between it and a Cornish 
boiler proper was that the latter had but one flue. If a high 
pressure, say of 80 lb. or 90 lb., was wanted, there must be very 



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MODERN SYSTEMS OF GENERATING STEAM. 69 

small flues, because the boiler must be of very small diameter. 
In the river boats in the United States there were boilers of 
3 feet or 3 feet 4 inches diameter with two 14-inch flues within 
them ; these boilers were sometimes as much as 30 feet long, 
and carried 140 lb. or 150 lb. of steam, and they were practi- 
cally safe if they were kept clean. But such boilers would not 
be fired with grates inside two 13-inch flues, or there would 
not be much steam. In the modern marine high-pressure 
boiler, 14 feet diameter, 10 feet long, carrying 80 lb. of steam, 
and with a shell 1£ inch thick, there was always a deficiency 
of grate surface, because there could not be got into them more 
than three furnace chambers. These boilers were perfectly 
safe, but they would not allow grate surface enough for good 
combustion. There was as much as 43 or 44 square feet of 
tube surface for each square foot of grate, which was more than 
was wanted, and, as a rule, the boilers were deficient in steam 
with reasonable firing. He was not speaking of economy, but 
of evapor&tive efficiency. If a Lancashire boiler was cut down 
to 5 feet or 5 feet 6 inches in diameter, in order to render it 
safe for high pressure, the grates were narrowed, and the flues 
became small, -and the user was driven to the Cornish boiler 
with one flue. So long as the pressures were kept down to 
50 lb. or 60 lb., there was not a much better boiler in the world 
than the Lancashire. In that case the diameter could be kept 
up to 7 feet, and there would be plenty of grate room. 

Mr. Houghton said that Mr. Pendred seemed to be inclined 
to large furnace surfaces, but, in his (the speaker's) opinion, 
they might carry the size of the furnace to too great an extent 
He had often found that reducing the length of the furnace 
improved the efficiency of the boiler. About three years ago, 
in some very important experiments carried out by the Govern- 
ment at Keyham Dockyard, it was found that a reduction in 
the size of the furnace improved the result to the extent of 
about i lb. of water to 1 lb. of coal. No furnace ought to be 
more than 7 feet in length, for it was impossible for the stoker 
to properly distribute the fuel over a long surface. He believed 
that the Blackburn explosion arose from the mode of fixing the 
boiler, the side flues being carried over the entire top area of 
the boiler, with the exception of a mid feather wall. For high 
pressure, a Cornish boiler of the proper thickness of plates with 
Galloway tubes was, he believed, as strong as anything they 
could possibly have. He should have no hesitation in using 
80 lb. or 90 lb. of steam in a properly proportioned Lancashire 
boiler. 

Mr. Pendred asked to be allowed to correct a mis-statement. 
Mr. Houghton had confounded furnace room with grate surface. 

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70 MODERN SYSTEMS OF GENERATING STEAM. 

The very objection which he (Mr. Pendred) had to a Lancashire 
boiler of small diameter was that there was a very long grate 
surface. The length of the grate must depend upon the pres- 
sure which was wanted. What he had said was that, if they 
used a small diameter Lancashire boiler, there must be small 
flues, and if there were small flues, the grate surface, to be of 
adequate extent, must be so long that no stoker could fire it 
properly. 

Mr. feiLLiNTON said that he had always had great faith in 
Lancashire boilers. It had been stated that if they wanted to 
work a Lancashire boiler at a good pressure they must increase 
the grate, and therefore the diameter, together with an increased 
thickness of plates and diameter of rivets, and there then would 
be a liability to bad workmanship. But would there not be an 
equal liability to bad workmanship in all the water-tube boilers ? 
And would not the result be as bad in the latter case as in the 
former? as the starting of any of these numerous joints in a 
heavy sea would seriously interfere with if not entirely stop the 
stoking. Explosions of Lancashire boilers had not been due to 
the fault of the boiler itself, but they had been due to the way 
in which they had been built and worked. Had they been 
built in the way in which Mr. Fairbairn first designed them, he 
(Mr. Billinton) believed that no explosions would have occurred, 
reople would have such things made too cheaply. He recom- 
mended that persons, instead of using fuel economizers, should 
put down an extra boiler, and work their boilers rather more 
slowly. They would not do so much harm as at present to 
their plates, and the boilers would be longer lived. The inser- 
tion of pipes and such things into the chimneys very often spoilt 
the draughts to a great extent. 

Mr. A. Wilson said that, as a user of steam power, he had 
recently been taking account of his consumption of coal, and he 
had succeeded in reducing it 30 per cent. He had undertaken 
to make a specimen boiler on Mr. Suckling's principle, and he 
should have it at work at his own premises in two months. He 
hoped that he should be able to give the Society, on a future 
occasion, particulars of its working. The consumption of the 
tubular boilers had not been put before the meeting, for he 
believed that no data had been brought before the public. He 
had been told that a boiler consisting of a series of small tubes, 
on Mr. Sinclair's patent system, had been put down in Edin- 
burgh, in which the circulation was to a certain extent secured. 
To his mind the principal difficulty in Sinclair's boiler would 
be to keep it tight. He had been assured that the boiler to 
which he had referred had superseded a good Cornish boiler, 
and that the consumption of coal fell directly from 40 cwt. to 

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MODERN SYSTEMS OF GENERATING STEAM. 71 

18 cwt. for the same work, and that the steam was much drier. 
It was possible that the Cornish boiler had primed considerably, 
and had so been a wasteful boiler. 

A point of great importance in boilers was the repairs they 
required. This was especially to be taken into account in 
places where boilers could not be repaired on the premises. 
He had worked an elephant boiler on his own premises for nine 
years, and it had not cost him anything for repairs. He had 
no doubt that it was *very well made. In the consumption of 
fuel, however, it was rather extravagant, and it would pay him 
to have a boiler that was more economical in that respect, even 
if it cost a little more for repairs. The Cornish boiler had been 
long approved, but there was no doubt that with bad water it 
required an immense. amount of repair. He had recently seen 
one under repair for the fourth time, after having worked only 
two years. It was then having a new plate over the fire, 
having been patched on the previous occasions. The water 
with which it had been supplied contained gypsum to a con- 
siderable-extent At the same shop a large number of portable 
boilers were under repair, requiring new fire-boxes. The fore- 
man informed him that these boilers always cracked across the 
tube plate, at the bottom row of tubes. His (Mr. Wilson's) idea 
of their cracking in that spot was, that in the generation of the 
steam that part was generally left free from water, and got too 
hot in consequence. In other respects the fire-boxes were per- 
fectly good. This cracking convinced him of the great advantage 
of circulating the water in the tubes. 

Mr. J. J. Miller, in reference to the allusion made by the 
last speaker to the elephant boiler, said that in a case which 
had come under his notice the economy of such a boiler had 
been greatly improved by the application of the Field tubes to 
it. The boiler was in a French town, and was worked with salt 
water. Speaking from memory, he believed that the economy 
effected by the introduction of the Field tubes into the shell of 
the boiler amounted to about 20 per cent. The boiler was fired 
between the legs, after the French fashion. The tubes which 
were added were ordinary Field tubes, about 2} inches in 
diameter, and 15 inches long. They were merely put radially 
in the shell, they were properly constructed with round ends. 
He believed that the fact of some of the tubes being con- 
structed with square ends had very considerably affected the 
results obtained from the Field boiler. In an instance which 
he had seen, the tubes, instead of being properly rounded, 
according to the latest practice, were drawn in about half an 
inch at the end for the sake of welding in a solid plug about 
f inch thick ; and the inner tube had been allowed to run down 

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72 MODERN SYSTEMS OF GENERATING STEAM. 

too far, preventing all circulation. The water was bad, and the 
consequence was that a sediment collected at the bottom of the 
tube when the boiler was not under steam, and which stopped 
the circulation. A considerable alteration was made, and the 
boiler worked better afterwards. 

Mr. P. F. Nurset said that he rose, not so much to make any 
remarks upon the principle of the invention described in the 
paper, as to add some information on the subject under con- 
sideration. There could be no question that the tendency of 
present practice in boiler construction was to greatly divide up 
the water spaces, and in steam engineering to work with the 
highest possible pressures. Within the last year or two he had 
made several runs with very high-pressure steam, used in 
Perkins's engines and boilers on board the ' Filga,' which was a 
boat not built for speed, but purchased by Mr. Perkins to fit his 
tubular boilers and compound engines in, and to test his prin- 
ciple of working at very high pressures. The boiler was con- 
structed of wrought-iron tubes, 3 inches in diameter and | inch 
thick, disposed in horizontal layers, and connected together by 
small vertical tubes. In the ' Filga' there were thirty sections 
of eight rows, seven rows being disposed above the furnace bars, 
and one row below them. The tubes were tested up to 2500 lb. 
per square inch. The engines of the ' Filga ' were compound, 
steam-jacketed, and fitted with overhead single-acting cylinders, 
two low pressure of 30 inches diameter, and two high pressure 
of 15 inches diameter, placed upon the low pressure. They 
were worked with double pistons, both fixed on the same rod, 
and having a 12-inch stroke. 

In one of the runs which he had made in her, there was 
185 lb. boiler pressure at starting. Subsequently the pressure 
reached 220 lb. with seventy-four revolutions per minute of the 
engines. The steam then went up by increments of 10 lb. 
from time to time, until the pressure ultimately reached 260 lb. 
They steamed some distance down the river and back again at 
that pressure, working at about eighty-nine revolutions. The 
coal consumption was very good. The result was an indicated 
power of about 205*49 horse-power as near as could be 
judged. The coal account showed a consumption of 2200 lb. in 
five hours thirty minutes, or 394 lb. per hour. The indicator 
diagrams were not taken with sufficient regularity to enable 
the exact consumption of fuel to be worked out, but 2 lb. per 
horse-power was approximately correct. Better results had 
been obtained in some of Mr. Perkins's land boilers. There 
were no condensers used on board the ' Filga.' The fuel was 
Merthyr-Tydvil coal. A more recent example of working with 
high-pressure steam was to be seen in the grounds of the 

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MODERN SYSTEMS OF GENERATING STEAM. 73 

International Exhibition last year. That was a small road 
engine sent there by Mr. Permns. It was of 20 horso-power, 
and used steam at 450 lb. pressure. He (Mr. Nursey) took 
several runs round the grounds on that engine with the gauge 
maintained at that pressure. Mr. Perkins had told him that 
he had boilers certified as doing from 1 lb. to 1^ lb. of fuel 
per horse-power per hour. There were many of Perkins's land 
boilers working at very high pressures, from 300 lb. to 400 lb. 
per square inch. 

Mr. Galloway said that there could be no question as to the 
value of economizing fuel, and he believed that the water-tube 
circulating boiler was a step in the right direction. He was 
recently very much struck at reading in one of the professional 
journals that it had been correctly estimated that out of every 
100 lb. of coal used in an engine about 72 lb. was wasted. 
If that was true, what a field there was for improvements in 
boilers. There was, however, a great difficulty in getting real 
practical inventions into general use. He had practically 
worked out the idea that the best means of promoting circula- 
tion, securing economy, and preventing explosions, was to force 
atmospheric air with the feed-water into the boilers, and he 
believed the principle to be correct. 

Mr. J. Bebnay8 wished to know whether any of Mr. Suck- 
ling's boilers were already at work in this country. There was, 
no doubt, a very great demand springing up for water-tube 
boilers, if they could be made safe and practicable in all their 
details. They had not yet been brought to that degree of 
perfection which rendered them practicable. He had for some 
time had before him the question of whether he should advise, 
for certain purposes, Cornish boilers or water-tube boilers ; and 
had at last recommended Cornish boilers using only 50 lb. or 
60 lb. of steam, rather than water-tube boilers with much 
higher pressures. He wished to ask whether the circulation 
really was perfected in Mr. Suckling's boiler. All the water- 
tube boilers professed to have perfected the circulation. He 
could not see how there could be perfect circulation in the 
middle tube while there were those bent tubes at the end, as 
shown in the diagram. There would be steam at one end and 
feed-water at the other. Then, as to the repairing of the boiler, 
he wished to know whether any of the interior tubes could be 
removed without the whole thing being taken down. The same 
question rose as to Mr. Halliday's boiler. With regard to 
cleaning, there seemed to be no way of getting at the tubes, as 
far as he could see, except with the steam jet, and that must in 
many cases make a sort of crust on the tubes, instead of getting 
the clean iron again exposed to the heat. 

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74 MODERN SYSTEMS OF GENERATING STEAM. 

Mr. N. J. Suckling, in reply, said that as to the circulation, 
he had tried many experiments, and he should be happy to 
show to those who had made inquiries on the subject, the 
working of a small glass tube which he had with him. (Experi- 
ments shown.) As to getting out the tubes, it would be 
observed that there was no joint either in the furnace, or 
facing it, and therefore no leaking could take place. Should 
it be necessary to withdraw any tube, the nuts could be loosened 
by a spanner, and the tubes withdrawn without trouble. Should 
there be no other tube to replace the one taken out, a blank 
flange could be put on, and the boiler would work with the 
same efficiency as before. The tubes were not resting on one 
another, the boiler having been designed with a view to 
avoiding that. The small tubes at the back were 3 inches in 
internal diameter, and therefore the quantity of water brought 
in would be something considerable. At the upper end they 
were considerably larger, to allow a freer escape of the steam. 
At the front end the large pipe B was raised about 6 inches to 
afford a good head of water. 

The inclination of the outside circulating pipe was con- 
siderable. The tendency, therefore, was for the water to be 
always filling the large pipe at the back, and then each tube 
drew from it. If the middle tube was evaporating a smaller 
quantity of water, there would be a slower circulation through 
it. The lower tube, being exposed to the intensest heat, would 
have a very rapid circulation, as it could draw as much water 
as required from its reservoir, the large tube at the back. 
Should there be any deposit in the water it would have a 
tendency to settle in that large pipe, and would not be baked, 
for it was not exposed to heat. The object was to connect the 
lower ends of the generating tubes to the roof of the large pipe 
D, so that no current in that pipe could interfere with the 
settling of the deposit. At the front they were connected to 
the under side, so that, if the deposit should have a tendency to 
settle, the upcoming currents would buoy it up, and it would 
pass away with the circulating water and settle on a surface not 
exposed to heat. He had found in other boilers that, where 
they had had horizontal or inclined inside circulating tubes, 
they were regularly baked up, and there was great difficulty in 
withdrawing them. He had also seen the " Field " tubes applied, 
sometimes with marked success, and sometimes with indifferent 
results. The reason he was not able to state. 

By the aid of large test tubes he tried an experiment by 
suspending an inner conceutric tube — open at each end— a 
small distance above the bottom of the outer one. But on 



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MODERN SYSTEMS OF GENERATING STEAM. 75 

steam being formed beneath it, in ascending it entered the 
lower end of the inner tube and impeded the downward flow of 
water. By fixing a cup of larger diameter than the inner tube 
a short distance below its orifice, a free escape was allowed for 
the descending water, while the steam generated beneath the 
cup was diverted and flowed up the annular space; thereby- 
assisting circulation by producing a sucking action at the lower 
end of the inner tube. 

Messrs. Howard, of Bedford, had found the same difficulty, 
for they closed the mouth of the inner pipe and cat slots round 
the sides. He did not know whether that plan answered. 
They abandoned inner circulating tubes, and for a time used an 
inner tube of (J shape,, open at the top. He fancied that 
arrangement was more feasible than the preceding one. With- 
out the cup there seemed to be a regular commotion in the 
tubes, and if the water was allowed to fall very low, there 
appeared to be a series of pulsations. The steam generated in 
the bottom of the outer tube rested there until it accumulated 
and had sufficient force to uplift the water, and thereby effect 
its escape ; the water would then drop down again. Therefore 
he gave up the inner tube, and tried to get circulation by 
keeping the columns of water separate, which gave him the idea 
of an outside circulating pipe. In the ' Hector ' a great dif- 
ficulty was experienced in Keeping steam in the boilers, and in 
keeping the bottom of the boiler tight. Another defect was, 
that the vertical conicaPtubes in the uptake were always being 
burnt away in the centre of their length. It might be that 
they were too long, for, as Mr. Pendred had very properly 
remarked, there should be some ratio between the length and 
the diameter. 

Another difficulty arose at the outset, but was overcome; 
some of the tubes were fixed very close to what he called the 
roof of the flue, and they caused a great deal of trouble by 
leaking at the ends. That row of tubes being withdrawn, the 
trouble ceased, and the boiler seemed to make steam more 
freely. It appeared that there was so little space left between 
the crown of the flue and the tubes, that the water could not 
get round quickly enough. He had seen the Galloway boiler 
working with most excellent results, and he believed that where 
the required pressure was not more than 50 lb. or 60 lb. on the 
square inch, it was as good a boiler of the large shell type as" 
anybody wanted. But if the thickness of the plates and the 
diameter of the rivets were increased to withstand high pres- 
sures, then there were at once difficulties in the manufacture, 
and expansion, with its attendant evils, set in. There was a 



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76 MODERN SYSTEMS OF GENERATING STEAM. 

tendency towards subdivided chambers for the higher pressures, 
and he believed that the tubular principle, like many other good 
things, would fight its way. 

If ample surface was allowed for making joints, he did not 
know what difficulty there could be. The difficulty was more 
a theoretical one than otherwise. Ample surface could be 
allowed in the " sectional boiler " by making large flanges. He 
did not see what difference there was in that respect between 
that case and that of a cylinder cover. Certainly, there were 
small radiating surfaces (which could be protected if desirable), 
but he did not consider that was a disadvantage, as boilers were 
daily seen at work entirely unclothed. In Mr. Halliday's boiler 
there appeared to be some good features, but he (Mr. Suckling) 
could not see how they were going to detect leakage in any of 
the caflt-iron heads, where the generating tubes were screwed in. 
He presumed that the tubes could not be withdrawn until the 
bolts were taken out, in which case the whole set would fall to 
pieces. 

The President said that there was no doubt that steam was 
now a necessary of life, and steam, too, of very high pressure. 
The discussion would seem to lead to the inference that water 
tube or tubulous boilers in some form or other would have to 
be used. How to get the most economical result from coal 
was one of the most important problems of the day. There 
was no doubt that it was with the steam generator, as producing 
weight, more than with the steam engine, which simply pro- 
duced velocity, that the battle of the forces would now have to 
be fought. He considered that they were much indebted to 
Mr. Suckling for giving them, in his paper, an opportunity of 
discussing the subject. 



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PLATE 1. 




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PLATE 2 . 

1 




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( 77 ) 



October Mh, 1874. 

WILLIAM MACGEORGE, Pbesidbnt, in the Chaib. 

MECHANICAL PUDDLING, 

By Pebbt F. Nubsby. 

In introducing the subject of mechanical puddling to the notice 
of the members of the Society of Engineers, the author would 
observe at the outset that he is well aware that much has of late 
been said and written upon the question. It is, however, a sub- 
ject which carries with it a direct interest for a portion of the 
profession only, namely, those members who are more imme- 
diately interested in or connected with the actual production of 
iron and steel. The greater proportion of professional men are 
simply users of those materials, and of necessity are less inter- 
ested in the method of their production than in the quality 
and character of the products. Not that they are indifferent 
to, much less ignorant of, the great principles and processes in 
course of development around them which are slowly but surely 
revolutionizing one of the most important industries in the 
world. But unless the subject is brought under the notice of 
such in a direct, and as it were a personal manner, it is often 
difficult for those whose creative faculties are constantly oc- 
cupied in the adaptation of iron to constructive purposes to 
realize the special processes by which the material with which 
they are most familiar is produced. But even assuming the 
senior members of the Society to be well acquainted with the 
subject, there still remain its junior members, to whom prac- 
tical information is at all times valuable, although it may not be 
at all times accessible. Should, therefore, some amongst us not 
find in the following paper so much that is new as they may 
have expected, the author would ask their forbearance for the 
sake of those whose opportunities for acquiring a knowledge of 
special subjects are from force of circumstances far more limited 
than are their desires for so doing. But the author believes 
that whether there be an abundance or lack of knowledge, there 
cannot fail to be in the minds of all an earnest interest in a 
subject which at the present time is one of the first import- 
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78 MECHANICAL PUDDLING. 

ance, in the development of which minds of the highest order 
have long been persistently engaged, and upon which many 
hundred thousand pounds have already been expended. The 
author has for several years past had opportunities of watching 
the progress of the question, and he now proposes to gather 
together the results of his observations and experiences, and to 
place them before his fellow members. 

The necessity of relieving the puddler from the severe and 
exhausting labour which his work imposes upon him, and to 
which use cannot habituate him, is becoming more and more 
imperative. Those who best know what that labour is, know 
also that to term it a degrading toil is by no means sensational. 
No wonder then that men having any pretensions to intelligence 
— and a good puddler must possess some intelligence — should 
decline to undertake the drudgery of expending their physical 
energy for hours together before a fierce furnace, stirring and 
rolling the first molten and then viscous mass of glowing metaL 
It is true that attempts have been made from time to time to 
ameliorate the condition of the puddler by the introduction of 
mechanical aids to manual labour ; but this is only meeting 
the difficulty half way, and, like most things done by halves, 
little if any success has attended these attempta What is de- 
manded is a radical change, not in the process of puddling, but 
in the means of effecting it, and this change is now very immi- 
nent ; in fact, to some extent it has already been carried out in 
practice, having been brought about by the successful applica- 
tion of mechanical principles, guided by the light of the highest 
science. 

THE ORDINARY PUDDLING FURNACE. 

At present the process of puddling— that is, of converting 
cast iron into malleable iron — continues to be performed for the 
most part much in the same manner as it was exactly ninety 

Sirs since, when the illustrious Cort first gave it to the world, 
e method devised by him and adopted in practice ever since 
consists in placing the metal to be puddled on the hearth of a 
reverberatory furnace, in which the fire is separated from the 
hearth by a low partition or bridge. By this arrangement the 
flame is conducted over the surface of the metal, creating an 
intense heat, while the bridge prevents the deleterious portions 
of the fuel mixing with the iron. The products of combustion, 
after acting upon the metal, pass to a tall chimney, over which 
a metal plate is suspended, by means of which the draught is 
regulated. The body of the furnace is so constructed that a 
stream of water or air circulates around it, and thus retards the 
deterioration of the materials composing it by the intense heat 

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MECHANICAL PUDDLING. 79 

to which they are subjected. The puddler effects his operations 
through a door opening on to the molten iron, and his work is 
to agitate the metal, so as to expose the whole of the charge to the 
action of the fire. This he does with an iron tool called a rabble, 
and with which, after the iron has passed through certain phases, 
he collects the metallic granules or particles, and rolls them 
together over the hearth in balls or blooms, measuring roughly 
14 inches in diameter. These blooms he afterwards removes 
from the furnace, and they are then subjected to pressure, which 
gives the iron homogeneity and fibre. The furnace in which 
the process of puddling is carried on is of the reverberatory form, 
and is seen in sectional elevation at Fig. 1. It is generally 
bound with iron by means of horizontal and vertical bars, and 
sometimes it is wholly encased with iron plates. The furnace is 
divided into three parts — the fireplace, the hearth, and the flue. 
The fire-door is seen at A, and the main working door at B, 
there being in some a third door at C for the introduction of 
the cast iron, which is gradually drawn towards the bridge. From 
what has been stated it will readily be conceived that the labour 
of the puddler is most severe and exhausting. Exposed to the 
intense heat and glare of molten iron in a reverberatory furnace 
for a period of about an hour and a half at one time, with but a 
few brief intervals of cessation, it is hardly a matter for wonder 
that ironmasters are complaining of the want of good puddlers, 
and even of the difficulty of obtaining puddlere at all. 

BOILED IRON. 

Boiling crude iron direct from the blast furnace is practised 
to a limited extent. By operating on fluid iron the coal con- 
sumed in melting the cold pigs, amounting to one-third of the 
entire consumption, is saved, and the certainty obtained that all 
the iron is perfectly melted before the boiling commences, 
thereby ensuring the greatest uniformity in quality. Yet, not- 
withstanding the acknowledged superiority of the boiling pro- 
cess in direct connection with the blast furnace, and the period 
which has elapsed since the system was first adopted, the num- 
ber of furnaces working on this plan is not large. The necessity 
of reconstructing the forge and bringing it inconveniently close 
to the blast furnace is a great objection to its extensive use 
in existing works, while in the erection of new ones the con- 
tracted space permitted for carrying on the operations of 
the blast furnace is a disadvantage. The crowding together 
of the boiling furnaces, so that they may be as near as pos- 
sible to the fall, operates against the success of this mode of 
working in close weather. Suspension of operations through 

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80 MECHANICAL PUDDLING. 

the exhaustion of the men, produced by the heat evolved by the 
blast and adjacent boiling furnace, is a common occurrence in 
these forges, and exists to a greater or less extent in some 
others. 

STEAM BABBLES. 

Attempts have been made from time to time to reduce the 
amount of physical labour involved in manual puddling, and 
some relief nas been experienced by the use of Dormoy's steam 
rotated rabble. This apparatus is in use in France and Austria, 
where it is stated to effect an increase in the yield of the furnace 
and to save both labour and fuel, the puddler having to guide it 
through the metal during a portion only of the process. Pud- 
dling with steam has been several times experimentallytried. 
The original experiments were made at the Dowlais Works, 
where the plan was in operation at several furnaces for some 
months. The invention was considered at the time to be a de- 
cided improvement, producing a superior quality and larger 
quantity of iron. The steam was brought down to the surface 
of the iron by a row of vertical telescopic pipes passing through 
the roof of the furnace, their depression and elevation being 
under the control of the puddler. On the withdrawal of the 
heat, the steam was directed on the fluid cinder until it was 
cooled down to a pasty consistency, when it was raked up against 
the back, sides, and bridge of the furnace, to fill up any cavity 
that may have been burned during the working of the heat. 
This operation on the cinder, enabling it to be used instead of 
clay or limestone, was considered a decided improvement to the 
quality of the iron, a less quantity of earthy matter combining 
with it during the puddling. The introduction of steam directly 
into the molten mass had also the effect of facilitating the pro- 
cess of conversion, and thus shortening the period of labour. 
After an extensive trial, however, it was discovered that the ad- 
vantages were not commensurate with the expense of applying 
and maintaining the apparatus. 

THE "JOE PICKLES" PUDDLEB. 

A contrivance, which appears to have answered its intended 
purpose satisfactorily, and which is known as the " Joe Pickles" 
mechanical puddler, is in use at the Eirkstall Forge Company's 
works near Leeds. It is the invention of Mr. Joseph Pickles, 
foreman millwright at the Eirkstall Forge. The principle in- 
volved is very similar to one often tried, the ordinary rabble 
being retained. The apparatus, which is illustrated at Fig. 2, 
consists of a framework of iron, a beam being mounted in bear- 



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MECHANICAL PUDDLING. 81 

ings, the beam being caused to oscillate on its centre by means 
of a crank or eccentric, motion being transmitted by means of a 
connecting rod. On the framework are fixed two short round 

{miliars, on each of which is a bracket fitted so as to radiate freely. 
Each bracket carries a bell-crank lever. The bell-crank levers 
are attached by connecting rods to the outer ends of the oscil- 
lating beam, whereby a vertical reciprocating motion is im- 
parted to them. A rabble of ordinary construction is attached 
to the other end of each bell-crank lever. A slow lateral radial 
reciprocating motion is given to the brackets mounted on the 

!>illars, and as the brackets carry with them the bell-crank 
evers, they impart to them the lateral radial reciprocating 
motion. By the combined vertical reciprocating and lateral 
radial motion of the bell-crank levers, the rabbles are traversed in 
all parts of the iron in the furnace, thereby thoroughly mixing it. 
The furnaces are of the ordinary type, and are made double. 
There are seven of these furnaces so fitted at the Kirkstall Forge, 
where they have been at work for nearly two years. The pud- 
dling engine has a 5-inch cylinder and 9-inch stroke, equal to 
2 horse-power. The Kirkstall Company could work two or three 
machines with this power, but they find it best to have an excess 
of power and a separate engine to each. A principal feature in 
these machines is a saving of labour, especially to the under- 
hand. In the Yorkshire district it is next to impossible to get 
underhand puddlers to work ordinary furnaces where grey pig is 
worked. The machines also ensure more regular work thau is 
obtained from hand-worked furnaces, the men being able to 
work the former in hot weather. The saving of coal is stated 
to be from 5 to 6 cwt. on the ton of puddled iron. Up to the 
present time the Kirkstall Company have paid the same rate of 
wages for puddling as by hand, but the price will, no doubt, 
eventually be reduced. The yield per ton is about the same as 
in hand puddling. 

These and similar contrivances, however, only meet the evil 
half way, and the fact remains that good puddlers are becoming 
more and more scarce every day. This, coupled with the cir- 
cumstance that the tendency of present practice is to deal with 
iron in masses of the largest size that can be manipulated, points 
out clearly that a radical change must be made in the method 
of carrying out the puddling process. That change would 
appear to consist in exactly reversing the method of manipu- 
lating the metal, so that instead of the iron being rolled and 
tumbled about in the puddling furnace, the furnace itself is 
made to revolve about the iron. 



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MECHANICAL PUDD1ING. 



WALKER AND WARREN. 



As far as records go, the original conception of this idea 
appears to date back to the year 1853, and to be due to Mr. 
Bernard Peard Walker and Mr. James Warren, who patented 
an arrangement shown in Fig. 3, and which consisted of an or- 
dinary furnace A communicating with the interior of a revolving 
puddling furnace B. The latter portion of the apparatus was a 
circular fire-brick chamber cased with iron and revolving on its 
horizontal axes, being supported in a set of V-g r <x>ved pulleys. 
The internal part of the puddling chamber, instead of being 
parallel with the axis of its motion, was formed at an angle with 
it, by which means, when the furnace was set in motion, the 
position of the metal within it was constantly varying. 

TOOTH AND YATE& 

Messrs. Walker and Warren, however, do not appear to have 
taken any steps to carry their theory of mechanical puddling 
into practice. That was left for Mr. W. Tooth, who in 1859 de- 
scribed in a provisional specification a drum-shaped furnace 
capable of being revolved on a horizontal axis, the lining being 
either made in moulds or cut into blocks of such form as to fit 
the circular chamber. In the following vear Mr. Tooth went 
thoroughly into the matter, and was the first to carry out the 
principle of mechanical puddling in practice. His revolving 
furnace is shown at Fig. 4, and consists of a rotating cylinder 
supported on friction rollers carried on a shaft which was re- 
volved, and thus. caused the chamber to revolve. The fireplace 
is seen at one end of the cylinder, and the exit flue, which is 
movable, at the other. Associated with Mr. Tooth in giving 
effect to the idea of mechanical puddling was Mr. William Yates, 
who improved some of the details of Mr. Tooth's apparatus. A 

Eatent in their joint names refers to the cooling of the furnace 
y water, although it does not show how the object is to be 
effected. In a subsequent patent, however, it was proposed to 
cool the furnace by a coil of pipes through which water was cir- 
culated. They also propose to use oxide of iron as a lining. In 
a subsequent patent, dated 1863, Mr. Tooth farther improves 
upon the details of the rotary puddler, and introduces several 
new features into the method of carrying out the process. This 
specification is remarkable for its comprehensiveness, and would 
seem to have left but little room for those workers in the same 
direction who were to follow. But, little though that room was, 
it appears to have been ample for some of Mr. Tooth's successors 
to make mechanical puddling a practical success, which Mr. 
Tooth did not. 



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MECHANICAL PUDDLING. 83 



MENELAUS. 

Messrs. Tooth and Yates' paddling furnace was pnt to the 
proof at the Dowlais Ironworks under the personal supervision 
of Mr. William Menelaus, who here deserves honourable mention 
for his strenuous endeavours to render mechanical puddling an 
accomplished fact. Step by step he brought the revolving fur- 
nace at Dowlais into working oraer, and to him is due the credit 
of such results as were obtained. Most anxiously and earnestly 
did he strive to make it a commercial success, and he nearly, 
but not quite, reached that point. His best efforts, however, 
were of no avail, as the fettling would not stand, and at. length 
mechanical puddling by Tooth's furnace had to be abandoned. 

In the year 1867 the members of the Institution of Mecha- 
nical Engineers held their summer meeting in Paris, and at 
that meeting the principles and practice of mechanical puddling 
were fully discussed. Mr. Menelaus there read a paper on the 
subject, and with a candour which is alike worthy of praise and 
imitation, he narrated the history of his failures. These he 
attributed to the failure of the lining in the puddling vessel. 
The chemical action of the melted metal and cinder, together 
with the mechanical action of the iron in its granular state, 
soon wore the lining away, and it became mixed with the iron, 
which was consequently rendered inferior in quality. But little 
injury was done to the fettling by the rolling of the iron when 
balled up. Mr. Menelaus found ganister to be one of the best 
lining materials ; it used to stand about 100 heats. Another 
kind of fettling he used was made of hard cinder and red ore, 
liquefied in the puddling vessel and allowed to cool gradually, 
while the chamber was being slowly revolved. The interior 
received a uniform coating, but that lining, like the rest, failed. 

In the discussion which followed the reading of Mr. Menelaus' 
paper, Mr. Edward Williams of Middlesbrough stated that he 
nad reproduced the Dowlais revolving puddler on an experi- 
mental scale, his revolver being 6 feet long by 3 feet in dia- 
meter. For fettling he mixed with the cinder scale from the 
shingling hammers and roughing down rolls. These he melted 
down in a furnace and ran very slowly into the revolving puddler, 
keeping the outside cool meanwhile by means of a copious 
stream of water. By this means he obtained a lining 2 inches 
in thickness. Mr. Williams also stated that he moulded the 
iron fettling into blocks, with which he lined the sides of the 
ordinary puddling furnaces. Here then was the starting point 
of the practice of lining furnaces with liquefied fettling, as well 
as of moulding it into blocks, and for which credit is due to 
Mr. Williams. At the same meeting Mr. E. Eiley, F.C.S., 

o 2 



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84 MECHANICAL PUDDLING, 

proposed the use of ball tap cinder for lining puddling furnaces, 
a proposition which has been carried into practice with good 
results. 

THE DANES FURNACE. 

About three years since the attention of ironmasters was 
anxiously drawn to a rotary puddling furnace invented by 
Mr. Samuel Danks, of Cincinnati, Ohio, which was reported to 
be producing remarkable results in the United States. This fur- 
nace is shown at Fig. 5, and has a fire-grate similar in outward 
appearance to that of the ordinary puddling furnace, although 
it differs from it in some of its details. It is supplied with a 
fan blast under the grate to urge the fire and produce gas, 
while the more perfect combustion of the fuel is ensured by jets 
of fan blast, which- are injected over the fire. The workman 
regulates this blast by a valve, so that the quantity of gas 
generated and consumed is controlled, and the temperature is 
thus made to suit the requirements of the charge of iron in the 
different stages of the puddling process. The ashpit and fire- 
hole are closed by doors, so that the blast can only escape 
through the fire, the firehole being kept cool by a stream of 
water passing through a coil of iron water-tubing cast into it. 
A similar coil is inserted in the bridge plate, between the fire 
and the charge of metal. Fastened into this bridge plate is an 
iron ring having a flat surface on one side, and which forms a 
butt joint with the revolving chamber. The flat surface of the 
ring is cast on a metal chill, which hardens it and protects it 
against abrasion from the end of the revolving chamber. 

This chamber is cylindrical in form, and is about 5 feet in 
diameter and 4 feet in length internally; each end of the 
chamber is supported externally by a pair of rollers, which, 
while they retain it in place, also permit of its free rotation. 
The chamber consists of two end rings, which hold together a 
series of stave plates, forming the circumference of the cylinder. 
The stave plates are made with hollow ribs extending their 
whole lengtn, and which serve the double purpose of holding 
the lining, or " fettling," as it is termed, and keeping it cool. 
The chamber is, of course, open at each end, one end butting 
against the bridge ring and the other serving the purpose of a 
doorway for the reception of the charges of iron, ana also for 
their removal. Through this outer end the products of com- 
bustion also pass, a movable head-piece being used to connect 
the revolving chamber with the chimney. This head-piece is 
furnished with a stopper-hole, through which the operation 
going on within can at all times be seen, the compartment 
being kept cool by means of an arrangement of water pipes. 
The products of combustion are led through an elbow flue into the 

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MECHANICAL PUDDLING. 85 

chimney, and there are arrangements for shutting off the blast 
and confining the fire within the furnace during the operations 
of charging the chamber and withdrawing the puddled ball. 
A revolving motion is imparted to the chamber through spur 
gearing by a pair of vertical reversible trunk engines, the spur 
wheel being fixed around the outside of the chamber. 

The foundation for the lining of the cylinder consists of a 
mixture of pulverized iron ore and lime worked with water into 
the consistency of a thick paste, which is laid on the inside of 
the chamber. Upon the completion of the initial lining a 
quantity of pulverized iron ore — about one-fifth of the total 
amount required to fettle the apparatus — is thrown in. The 
furnace is then heated and revolved slowly until the iron is 
found to be melted, when the engines are stopped. The initial 
lining has now received a coat of glazing, and that part of the 
molten iron which has not been consumed runs to the bottom 
of the cylinder and there forms a pool. In this pool are 
placed lumps of iron ore, which project from 3 inches to 
6 inches above the surface of the liquid ore. When this por- 
tion of the fettling has set, another charge of pulverized ore is 
introduced by its side, and the chamber is again rotated until 
the newly added ore is liquefied, when the apparatus is stopped, 
and the pool filled with lumps of iron ore as before. The 
operation is continued in this way until the whole of the interior 
of the vessel is properly fettled. It is then ready for the 
charge of iron, which is introduced, either in the solid or molten 
condition, through the open end of the cyliuder. When charged 
with pig iron the melting down occupies from thirty to thirty- # 
five minutes, during which time a partial rotation is given to 
the furnace at intervals in order to expose equally all sides of 
the charge to the flame. 

When the whole of this is thoroughly melte 1 the furnace is 
rotated once or twice per minute only during the first five or 
ten minutes, in order to obtain the most perfect action of the 
cinder upon the molten iron. A stream of water is then in- 
jected through the stopper-hole in the head-piece along and 
just above the line of contact between the cinder and the inner 
surface of the vessel on the descending side. A portion of cinder 
is by this means solidified on the metal surface, and is carried 
down into the bath of molten iron in a continuous stream. This 
cinder, in rising up through the iron, combines with the impuri- 
ties of the latter in a very effectual and complete manner. The 
iron then begins to thicken, when the engines are stopped, and 
the heat raised so that the cinder may be perfectly liquefied. 
This liquid cinder is then run off from the top of the iron, after 
which the chamber is again started at a velocity of from six to 
eight revolutions per minute. This causes the charge of iron 

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66 MECHANICAL PUDDLING. 

to be dashed violently about in the chamber ; and this action 
being continued at a high temperature, the particles of iron 
begin to cohere. The speed is then lowered to about three 
revolutions per minute, upon which the ball rapidly forms. 
The puddler then solidifies the front end of the ball by a few 
blows from a tool applied through the stopper-hole ; the head- 
piece is removed and the ball withdrawn by means of a large 
fork introduced into the chamber, out of which the ball is 
rolled by a partial turn of the cylinder. In Cincinnati, where 
the first of these furnaces was put up, puddled balls are reported 
to have been made weighing from 650 lb. to 1000 lb. each. 
Balls of smaller size can, however, be produced by the assist- 
ance of hand labour to suit existing hammers, or squeezers, 
although of course the machine is most economically worked 
when producing large balls, for which a special squeezer has 
been aesigned by Mr. Danks. The increase in the yield of 
puddled iron above the quantity of pig iron put into the furnace 
has been from 10 to 15 per cent. This arises from the revolving 
chamber itself being fettled with iron ore, as much as 50 per 
cent, of iron being sometimes obtained out of the fettling. 

The success of the Danks furnace grew from small begin- 
nings. Its inventor commenced his experiments with his rotary 
furnace on a small scale at the Cincinnati Bailway Works, in 
May, 1868, and upon the results proving successful larger fur- 
naces were built in the following year. In 1870 the continued 
success of the apparatus led to the substitution of Danks fur- 
naces for the hand-puddling furnaces throughout the works. 
ThQ success of the new furnace at the Cincinnati Works led to 
its adoption at many other similar establishments in the United 
States. In England it was first brought under the notice of 
ironmasters through the Iron and Steel Institute in 1871. 
The invention was carefully investigated, and was considered 
of sufficient importance to justify the Institute in sending a 
commission to America to thoroughly test and report upon its 
working in that country. Mr. Snelus, Mr. J. A. Jones, and 
Mr. Lester were appointed commissioners, and they took with 
them 40 tons of pig iron and a quantity of fettling material. 
Experiments were carried out at the Cincinnati Works, and 
every other place in America where the Danks furnace was 
then at work was visited by them. The results as reported to 
the Institute were eminently satisfactory, establishing beyond 
doubt the value of the system. 

Besides the joint report of the commissioners, they also 
reported individually. Mr. Snelus made an exhaustive series 
of chemical analyses, the results of which he reported, his con- 
clusions being in every way favourable to the Danks furnace. 
Mr. Jones' report contained comparative statements of the cost 

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MECHANICAL PUDDLING. 87 

of puddling furnaces on the Danks principle and on the ordi- 
nary system. He estimated that worts made up of 50 puddling 
furnaces turning out 600 tons of bars per week would cost 
33,0007.; Danks' plant for turning out the same amount of 
work would cost 34,000/., but it was estimated that twelve 
Danks furnaces would puddle as much as fifty ordinary fur- 
naces, and no fewer than ten heats of 10 cwt charges were 
expected every twelve hours. Mr. Lester in his report entered 
into the details of the practical working of the machine, 
describing the method of lining, charging, and operating the 
apparatus. His conclusions were that no number of men 
could operate so perfectly in puddling iron as could the 
mechanical furnace of Mr. Danks, in the working of which 
muscle and animal power are not so much required as care and 
intelligence. By the Danks furnace not only is the necessity 
for employing manual labour in the actual work of puddling 
obviated, but larger balls are produced than by hand, and a 
great saving is effected on the whole process. The absolute 
saving was stated by Mr. Danks to be at least 1/. per ton, 
although the Committee of the Iron and Steel Institute placed 
it at 10s. 8d. per ton. The committee, however, admitted that 
the profit might prove much greater in practice than they had 
stated, but they had purposely placed it low, wishing to under- 
estimate rather than to over-estimate the commercial value of 
the invention. 

The satisfactory nature of the report of the committee 
quickly led to the adoption of the Danks furnace at several 
ironworks in England, with the view of giving it a proper trial. 
The works adopting it were Messrs. Bolckow, Vaughan and 
Company, Middlesbrough, who speedily had two experimental 
furnaces in operation ; Messrs. Hopkins, Gilkes, and Company, 
who erected a complete forge, comprising two melting cupolas, 
twelve revolving furnaces, with powerful shingling machines, 
and a set of three-high rolls, for reducing the blooms into bars. 
The Erimus Iron Company, Middlesbrough, built a complete 
forge, consisting of twelve furnaces, to which is now being 
added a finishing mill, for working up the products into mer- 
chantable iron. The North of England Industrial Iron Com- 
pany, at their works near Stockton, erected a forge, consisting 
of eight Danks furnaces, with the requisite machinery for obtain- 
ing puddled bars. In addition to these establishments on the 
Tees, or in its neighbourhood, Mr. .Robert Heath constructed 
six furnaces in North Staffordshire. 

It is to be regretted that such an outlay of capital as must have 
been involved in the erection of the plant and machinery at these 
works has not been justified by the results, which in plain terms 
show the Danks furnace to be so far commercially unsuccessful 



ioogle 



88 MECHANICAL PUDDLING. 

in England. In an address delivered to the members of the 
Iron and Steel Institute, on the ftth of May last, the President of 
that body, Mr. I. Lowthian Bell, states the case very clearly, and 
gives the following as his explanation of the causes of failure: 

" It must be admitted that the success which has attended 
the substitution in this country of the new for the old plan 
of hand puddling has not invariably corresponded with the 
accounts given us by those gentlemen who reported upon its 
introduction in the United States. Nevertheless, I would not 
have it supposed that I am impugning in any degree the 
soundness of their observations while engaged in their mission. 
It is quite possible that American iron may offer less difficulties 
while under treatment in a Danks furnace than that of this 
country. It is also equally possible that those difficulties 
which have been encountered m a continuous application of 
iron, such as that produced in Cleveland, may not nave been so 
apparent when treated in more limited quantities during the 
comparatively short trials made under the personal superinten- 
dence of our commissioners. Referring now more particularly 
to the North of England, I have to observe that some altera- 
tions have even been found necessary in the moving, as well as 
in other portions of the machinery. These minor defects, so 
far as I can learn, have been overcome, but there remains 
the one great impediment to success, viz. the durability of the 
lining of the furnace. Upon this branch of the question the 
testimony obtained in the North of England is somewhat con- 
flicting. At one establishment, the entire plant, after some 
months of work, has been laid idle, and preparations are there 
in progress to alter the furnaces to the plan recommended by 
Mr. Crampton. On the other hand, while admitting the exist- 
ence of difficulties not yet entirely vanquished, the practical 
men who are directing the trials express themselves confident 
of ultimate success." 

80 far Mr. Bell ; and the author may add that he has heard 
these views more than confirmed by those who have used the 
Danks furnace in England. At the same time it is only fair to 
state that he has also heard most hopeful opinions expressed 
by those who are also working the Danks process. The greatest 
impediment to success appears to be the want of durability in 
the lining, and the next, mechanical failure. To these a third 
was added by Mr. John A. Jones, of the Ayrton Boiling Mills, 
Middlesbrough, which was — want of skill on the part of the 
workmen. In May last, however, Mr. Jones stated that at the 
Ayrton Works the men had been educated to the work, and 
the fettling difficulty had been overcome by melting both the 
fettling and the charge outside the machine. The mechanical 
failure, however, he admited had not then been remedied, and 

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e 



MECHANICAL PUDDLING. 89 

the Danks machine had by degrees given way in every part, 
doubling the fuel and labour account. He was, however, hopeful, 
that in six months he should be able to announce a satisfactory 
solution to the question of mechanical puddling. It is sincerely 
to be hoped that such will be the case, although the author still 
has his doubts upon the subject — doubts which were not re- 
solved by a statement he recently heard made by General 
Wilder, to the effect that at his works at Chattanooga he was 
removing an entire plant of ten Danks furnaces, and replacing 
them by a set of double puddling furnaces. 

THE SPENCEB FURNACE. 

Mr. Adam Spencer has solved the question of mechanical 
puddling at the West Hartlepool Ironworks, so far as the 
economical production of good metal is concerned. In his 
revolving furnace the grate is of the ordinary shape and con- 
struction, but in size proportionate to the capacity of the 
revolving chamber. The bridge is a common water-bridge, 
open to the top and bolted on the end plate of the furnace. 
The bridge neck has a flange or ring upon it, for the double 
lurpose of confining the brickwork immediately above the 
ridge, and for supporting a loose ring, which serves to form a 
close joint between the fire-grate and the revolving chamber. 
The revolving chamber is a long square box, the internal 
dimensions being, when fettled, 9 feet 6 inches by 4 feet 
8 inches. All the sides are parallel to the axis of rotation, the 
advantages of this being that each side can be fettled with the 
molten cinder, so as to have a perfectly level surface and of an 
even thickness throughout. The sides are composed of open 
trays or girders of cast iron, placed transversely in order to 
resist the torsion when revolving. The machine is supported 
at each end by a east-iron disc ; there is also in the middle of 
its length a third disc or ring as an additional support. These 
three discs which carry the chamber revolve on large rollers 
fixed in a strong frame and bed-plate beneath the machine. 
At the flue end of the chamber a movable neck is placed, made 
of wrought-iron lined with fire-bricks, which forms the junction 
with the chimney, provided at the lower end with a cast-iron 
mouth-piece in halves, suitable guides, and means of lifting. 
The chimney is of the ordinary type, having a wrought-iron 
mouth-piece on its side corresponding with that of the sliding 
neck, and is supported upon girders and columns, made suffi- 
ciently strong with the intention ultimately of placing a boiler - 
to utilize the waste heat. 

The fettling is composed of mill tap, or mill tap mixed with 
roll scale or any other suitable oxide of iron cast into the sides, 

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90 MECHANICAL PUDDLING. 

and is built in blocks properly moulded against the ends, the 
whole being cemented together by molten tap into one smooth 
and regular form. The repairing is done by means of wrought- 
iron spouts, which convey the molten fettling direct to either 
end or sides, as may be required, and occupies about three 
minutes. The charge of iron is melted in a cupola, and then 
carried by a spout to the flue end of the revolving chamber. In 
the movable neck a small door is opened, which admits a spout 
mounted on wheels, which reaches over the joint and dips 
slightly so as to allow the iron to run freely and lessen the 
height which it has to fall. Immediately the iron begins to 
flow the chamber is made to revolve slowly, thus preventing the 
iron eating into the bottom, and at the same time hastening its 
conversion. The charging of a ton of iron occupies about 
three minutes. When completed the spout is withdrawn from 
the neck, the small door closed, and the revolving of the 
chamber continued. The boil begins in about five minutes, and 
continues from ten to fifteen minutes ; the coming to nature, 
dropping, and balling occupies ten or fifteen minutes more. If 
several balls are required the operation going on inside the 
chamber is observed very carefully through spy-holes in the 
neck, and when balls of a sufficient size are formed the machine 
is immediately stopped. Should the whole heat be wanted in 
one mass or ball, the chamber is allowed to continue revolving 
slowly, and the firing kept well up for about ten minutes, when 
one compact and well-formed ball is the result. The with- 
drawing of the heat is effected by a pair of long tongs mounted 
on rollers, attached by a chain to a small hauling engine. 

According to Mr. Spencer's statement he has effected a 
saving of 15s. per ton of puddled bar in materials and fuel. 
No allowance is here made for difference in labour cost, which 
Mr. Spencer assumes will be materially reduced with a number 
of machines. This saving was calculated upon twelve months' 
working, with an output of over 2000 tons of puddled iron, the 
largest week's work being 100 tons, and the largest shift's work 
11 tons. Mr. Spencer's furnace, however, is not at present at 
work, having stopped at the end of last year. Since then the 
works have been under reorganization, and the delay in adopting 
the revolver is stated to be due to the time requisite to consider 
the steps essential to arrange the preliminaries for a large 
acquisition of plant. Mr. Spencer has produced iron of the 
highest quality from Cleveland pig, out of which rails, plates, 
sheets, rods, and hoops, have been made and tested by the 
highest standards. While giving Mr. Spencer every credit for 
having brought his puddling machine into good working order, 
and for having produced satisfactory results from it, the 

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MECHANICAL FUDDLING. 91 

author would observe that the notion of fettling with molten 
cinder and tap was clearly published to the world at the Paris 
meeting of the Institution of Mechanical Engineers in 1867, as 
already stated. 

THE SELLERS FUKNACE. 

One of the most earnest exponents of mechanical puddling in 
the United States is Mr. William Sellers, whose rotary puddling 
machine is shown in longitudinal section at Fi". 6 and in plan 
at Fig. 7, and who has materially improved the system gene- 
rally. In all machines prior to the Sellers machine, the flame 
was passed into, through, and out of the puddling chamber, 
in the direction of the axis of the vessel, as will be seen by 
a reference to the diagrams, the entrance and exit of the 
flame taking place respectively at opposite ends of the chamber. 
In Mr. Sellers' machine the flame passes into the puddling 
chamber — which is spherical in form — in the direction of its 
axis; but instead of passing through the'chamber and out at the 
other end, it sweeps over the whole of its interior surface, and 
returns and passes out of an opening in the end of the chamber 
at which it entered, thus operating more effectually upon the 
metal, and with increased economy. Whilst giving Mr. Sellers 
every credit for ingenuity, the author would observe that he was 
not the first to promulgate the idea of returning the flame. 
Mr. T. E. Crampton, who has played a very important part in 
the development of mechanical puddling, previously proposed 
the same thing, as will presently be shown. There is, however, 
this great distinction to be made between the Sellers and the 
Crampton systems, that whereas Sellers circulates through his 
furnace a flame which is the result of combustion going on out- 
side it, Crampton circulates through his furnace the fiiel itself 
in a state of perfect combustion. 

Another feature in Mr. Sellers' furnace is the arrangement 
for charging and discharging the furnace. These operations 
are performed for the most part, in other systems, either by 
lifting the puddling chamber bodily, or by removing a portion 
of the flue. In Mr. Sellers' machine the delivering and the dis- 
charging flues for the flame are arranged in the same vertical 
plane, and the revolving chamber is supported upon a tra- 
versing frame which vibrates through an arc of a circle about a 
vertical axis. The axis of the revolving vessel is tangential to 
the arc of vibration of the frame, so tnat the vessel may be 
swung round out of its normal operative position, in which its 
axis is perpendicular to the vertical plane of the flues, until 
its axis is brought parallel with the vertical plane of the flues. 
In this position the mouth of the chamber is accessible for the 

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\ 92 MECHANICAL PUDDLING. 

! 



convenient charging or discharging of the metal, without either 
removing any part of the flue or lifting the vessel. The frame 
which supports the revolving chamber also carries the engine 
for revolving it* and the steam for the engine is carried through 
the vertical axis about which the frame vibrates, and this con- 
stitutes an additional feature of the Sellers furnace. To attain 
the highest mechanical perfection it is necessary to provide 
against anything which might, even in degree, detract from its 
efficiency, and as the variations of temperature inseparable from 
the operation might disturb the proper relation of the parts, 
Mr. Sellers provides for such adjustments of the frame which 
carries the vessel as will compensate any such disturbance. As 
yet, however, Mr. Sellers has not shown his system of puddling 
to be a commercial success, although the author understands 
him to be in a fair way of doing so shortly. 

THE SIEMENS — ALLEYNE FURNACE. 

Dr. C. W. Siemens — who has this day been elected an 
honorary member of our Society — has worked out to a suc- 
cessful issue some very important improvements in the metal- 
lurgical production of iron and steel, which metals are now 
being largely produced by his direct process. Dr. Siemens' is 
not a puddling machine, yet, as it has been adapted to that 

Eurpose, it will be necessary briefly to describe it. The furnace 
y which Dr. Siemens is producing both steel and wrought iron 
at several large works is on the rotative principle, and is 
arranged as a regenerative gas furnace. Intensely heated air 
is introduced just above the charge, to consume the carbonic 
oxide formed at one stage of the process, and which is thus 
utilized instead of being wasted, as in the blast furnace. The 
rotator is a chamber 8 feet 6 inches long and 7 feet in diameter, 
and is revolved through proper gearing. This chamber is lined 
with bricks made of bauxite — a refractory mineral well adapted 
to resist the high temperatures required. In this apparatus a 
charge of 15 cwt. of wrought irog is produced direct from the 
ore in about three hours, and with a consumption of 25 cwt. of 
coal to the ton of metal thus manufactured. This is about half 
the quantity of fuel required for making a ton of pig iron in 
the blast furnace. The author has examined samples of iron 
and steel of very high quality which were manufactured by this 

Process by Messrs. Yickers and Co., of Sheffield ; at the Landore 
teel Works, Swansea; and at the Sample Steel Works, 
Birmingham. The application of the Siemens rotating furnace 
to puddling has been effected by Sir John AUeyne, at the 
Butterley Works, he having altered some of the details to suit 
the process of puddling. In what these alterations consist and 

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MECHANICAL PUDDLING. 93 

what results have been obtained the author is not at present 
able to state, as in a letter recently received from Sir John 
Alleyne he informs the author that at the Butterley Works they 
are carrying out a series of experiments, analyses of iron, &c, 
and have not made sufficient progress to enable them to afford 
any precise information upon the subject at present. 

THE CRAMPTON FDBNAOE. 

However valuable and important the process of mechanical 
puddling may be when carried out by the aid of the fuel ordi- 
narily placed at the disposal of the ironmaster, that value 
becomes greatly enhanced and that importance materially 
heightened when sound, practical results are obtained by 
means of fuel which is ordinarily considered to be but so much 
waste. It is therefore with special satisfaction that the author 
approaches that part of his subject in which he has taken great 
interest, and has carefully watched for several years past. This 
is mechanical puddling effected by means of coal-dust fuel, 
which process has now been perfected by Mr. Thomas Russell 
Crampton, to whom the autnor has already made a passing 
allusion. Considering the double object in view, the success 
already attained and the wide application of which the principle 
is capable, it is not too much to say that Mr. Crampton's in- 
vention is one of the most important — if not the most important 
— the present age has witnessed. And this will be realized 
when it is considered that coal is, in some districts, only 
obtainable at perfectly prohibitory prices, whilst the iron ore 
is there in abundance awaiting conversion. It is true that if 
the mountain will not come to Mahomet, Mahomet must go to 
the mountain ; and so the iron goes to the coal, but at what a 
loss those best know who would gladly invest capital in reduction 
works if they could but get fuel at anything like a reasonable 
price. If then slack ana coal-dust can be profitably utilized, it 
must speedily become remunerative both to colliery proprietors 
and to those whom it would convert from mine-owners into iron- 
masters. Another advantage realized by Mr. Crampton is the 
perfect combustion of fuel, as evidenced by the entire absence 
of smoke. This and the utilization of waste coal form two 

auestions, the attempted solution of which dates back nearly to 
tie first discovery of coal. Except in experiments these ques- 
tions have probably never been solved separately, certainly not 
in conjunction until now. Coal-dust has been utilized in the 
manufacture of patent fuel, being combined with various sub- 
stances to give cohesion to the particles ; but although others 
have attempted to do so, it remained for Mr. Crampton to 
demonstrate practically that coal-dust pure and simple could 

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94 MECHANICAL PUDDLING. 

be burnt alone and in a powdered condition, and that so burnt, 
perfect combustion could be attained. This result has only 
been reached through a long course of patient investigation and 
practical research, and by the consumption of between two and 
three thousand tons of coal in different furnaces in various 
parts of the country. It is more than six years since Mr. 
Crampton first commenced to give effect to his ideas, and 
during that period his coal-dust furnace has passed through 
many phases, until at the present time results show it to be 
simply perfect. 

The successful action of the Crampton furnace depends upon 
the introduction, under pressure, of atmospheric air and coal- 
dust, in -carefully adjusted proportions, and so commingled and 
delivered at a precise and undeviatingly fixed point, as that not 
an atom shall pass unconsumed. This completeness of com- 
bustion depends upon the proper admixture of the surcharged 
and undercharged currents of air and powdered fuel. To follow 
Mr. Crampton through the various phases of reasoning and 
experiment by which ne has perfected his invention might prove 
tedious, and would serve no practical purpose here. It will 
suffice to take the invention as it now is, and to describe its prin- 
ciples, its construction, and its practice. 

The principle of the Crampton furnace consists in the intro- 
duction of streams of air and powdered coal, mingled together 
and burned in a chamber in which the resultant heat is utilized 
in converting cast into wrought iron. The great difficulty which 
Mr. Crampton had to overcome was the tendency of the atoms 
of fuel to separate from the air, and therefore to be deposited 
on the metal or in the flue in an unconsumed condition. Mr. 
Crampton's first revolving furnace — the working of which the 
author has many times inspected at the Royal Arsenal, Wool- 
wich — was a two-chambered puddling machine, one of which 
chambers was lined with fire-brick forming a combustion 
chamber, into which the pulverized coal and air were injected, 
the gases being therein generated and principally consumed. 
The products of combustion passed into the second chamber, 
lined with oxide of iron, in which the puddling was effected. 
This machine was in use up to the end of last year, but since 
then the apparatus has been considerably simplified, the 
combustion chamber being now entirely dispensed with, and 
the generation of the gas and its combustion taking place in 
the puddling chamber itself, directly over the material under 
treatment. 

The Crampton furnace as at present constructed is shown at 
Figs. 8, 9, and 10, Fig. 8 being a side elevation, Fig. 9 a longi- 
tudinal, and Fig. 10 a transverse section. It consists of a 
single revolving chamber A, which is rotated by a small three- 
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MECHANICAL PUDDLING. 95 

cylinder engine. The chamber is 6 feet 8 inches outside 
diameter, and of the same length, and has an outer casing or 
water space, and the speed can be adjusted to any velocity up 
to say fifteen revolutions per minute. The chamber has a 
refractory lining B and revolves on wheels C C. It has a 
movable flue-piece D, which is lined with a refractory material, 
and is capable of being removed when access to the furnace is 
required. The flue-piece turns on a column D\ and is kept up 
to the furnace by screws. There is a long opening F in the 
movable flue-piece through which the air and fuel are injected. 
Small doors are used for covering any portion of the opening 
when required. An adjustable injecting pipe G is used, the 
end of which can be raised or lowered for conveying the fuel and 
air into the furnace in the required direction. The air and fuel 
are conveyed from the reservoir by a tube. The injecting 
pipe has several divisions in the bend for the purpose of pre- 
venting the fuel and air separating through the fuel running 
alone on the outside of the bend. The admission and exit of 
the water to and from the double casing is controlled by a 
double-way water cock. The flow of water is shown by arrows : 
it enters at I, passes into the pipe J, and is delivered at the end 
E ; it then disseminates throughout the whole of the casing, 
and makes its exit at the end of the pipe L, thence to the cock 
H, where it leaves by the pipe N. The water is then conducted 
by this pipe to the flue-piece, entering it at the lowest point 
through a flexible tube, making its exit at the highest point, 
and is then conducted by a pipe to a small chamber round the 
bottom of the column V\ on which the flue-piece swings, this 
chamber being connected with the general drainage of the worka 
The wearing joints of the furnace and flue are directly in con- 
tact with the water in the casing, these rings beingrenewed 
when required. 

The mode of constructing the water casing is one of the chief 
features of Mr. Crampton 8 furnace, and a most important 
feature it is. The amount of protection from injury which this 
water casing affords is in fact far greater than would have been 
generally deemed possible had it not been demonstrated by 
practical experience. So great is it that Mr. Crampton's first 
revolving furnace has been worked with as much as from 16 to 
18 square feet of the plate surface at the ends left entirely un- 
covered by lining, without any injury ensuing. 

The Crampton furnace at Woolwich is supplied with fuel by 
means of a very simple apparatus, which is placed out of the 
way in a corner of the building. Ordinary waste coal-dust is 
reduced to a state of fine powder by being ground between a 
pair of common millstones and afterwards passed through sieves 
of the required degree of fineness. It is found that the greatest 

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96 MECHANICAL PUDDLING. 

amount of useful effect is obtained from fuel which has passed 
through sieves having 2500 meshes to the square inch. From 
the sieves the fuel, which costs about one shilling per ton to 
prepare, is conducted by an Archimedean screw to the feeding 
apparatus, which consists of a square chamber or hopper having 
two revolving stirrers, so arranged at the bottom that the whole 
area of fuel is .kept in a state of gentle agitation. These stirrers 
force the fuel through a horizontal opening in front of the 
hopper on to a pair of adjustable rollers of different diameters, 

{)laced with their axes one above the other in a nearly vertical 
ine. By this means a continuous and unvarying supply of fuel 
is delivered by the aid of an induced current into a tube leading 
into the furnace. The fuel first passes through the flue-piece 
into the chamber, which it traverses, returning through the flue 
to the chimney. Both the supply of fuel and that of air can be 
regulated with the utmost precision according to requirement. 
The induced current of air is produced by a fan. 

Having described the principles of the Cramuton furnace and 
the method of its construction, the author will next proceed to 
explain its working, which is carried out in a very simple 
manner. Assuming the furnace to be cold, the flue-piece is 
removed and some wood is placed in the chamber and lighted. 
The flue-piece is then swung back into its place and air is blown 
in until the wood is in a state of energetic combustion. The 
injection of the powdered fuel is then commenced and continued 
for about forty-five minutes, by which time the furnace is white 
hot and ready for receiving a charge of metaL About 4 cwt of 
fuel is used in the preliminary heating, and the rapidity with 
which the furnace can be got ready for puddling is a very 
striking feature. None of the fuel blown in during the prelimi- 
nary heating remains unconsumed, the combustion being perfect 
The furnace being heated, a charge of from 8 cwt. to 10 cwt. of 
cold iron is placed in it, and the air and fuel again injected 
for about three-quarters of an hour, the time varying slightly 
according to the weight of the charge. As soon as the iron is 
melted the furnace is revolved slowly, and the puddling process 
is continued until the ball is formed, when it is withdrawn and 
dealt with in the usual way — under the hammer. The lining is 
then repaired, the furnace recharged, and another heat turned out. 
The repairing of the lining demands a passing remark. The 
furnace is lined with oxide of iron, and owing to the protective 
action of the water casing the lining is found to give no trouble. 
The chamber of the furnace is pentagonal in cross section, and 
one side of the pentagon is repaired after each charge, the five 
sides being treated in rotation, and the whole lining being thus 
repaired in the course of five charges. When a charge is drawn 



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MECHANICAL PUDDLING. 97 

,a portion of the fluid cinder is left in the furnace, and into this 
are thrown lumps of cold fettling which imbed themselves in 
the cinder, and which are raked down level. The new metal 
is immediately charged on the top of the lumps of fettling, the 
operation of drawing one charge, repairing the lining, and re- 
charging being accomplished on an average in eight minutes, 
while it has often been done in six. The fettling usually 
employed consists of lumps of ball furnace tap cinder, but 
puddle cinder and other fettling materials have also been 
successfully used. 

With regard to the results of working, the author may observe 
that in the ordinary puddling furnace the loss in the yield of 
iron ranges from 6 to 10 per cent., while with Mr. Crampton's 
double-chambered furnace there was a gain of from 5 to 10 
per cent. This gain is of course due to the fettling, the iron 
from which is converted and runs into the general mass. The 
quality of the metal from the ordinary furnaces, after being 
puddled, welded, and rolled three times, is such as to enable it 
to stand a tensile strain of about 22 tons per square inch with a 
certain amount of extension before fracture. With iron pro- 
duced by Mr. Crampton's first revolving furnace, however, it 
was found that by reheating the puddled ball once only and 
rolling it, practically the same extension before breaking was 
obtained, while the tensile strain was never under 23 tons, and 
was frequently as high as 26 and 28 tons per square inch. 
When that iron was hardened samples broke at 39 and 46 tons 
to the inch respectively, the iron retaining the true character of 
fracture, and extension being of a far higher quality than that 
produced by the ordinary system. In fact the results obtained 
with Mr. Crampton's furnace at Woolwich have invariably been 
most satisfactory, both as regards quality of metal and economy 
of production. 

To indicate precisely the work done at Woolwich by the 
present single-chambered furnace, the author cannot do better 
than give the results of some trials recently carried out for 
Mr. Briggs, of the Carlton Ironworks, the metal puddled being 
Cleveland iron sent by Mr. Briggs. The author takes the 
figures given by the gentleman engaged by Mr. Briggs, and 
which have been confirmed by subsequent working. They 
show that the pig iron charged was 353 cwt., and produced 
405 cwt. 25 lb. of puddled bar, showing an increase of 14*544 

Ser cent. To produce this 405 cwt. 25 lb., the weight of pow- 
ered coal was 284 cwt. 8 lb. or 14*02 cwt. per ton of puddled bar, 
including melting the cold pig. This quantity of iron was 
puddled in 53 heats, in 80 hours 38 minutes, including charging, 
fettling, &c, or 1 hour 31 minutes for each heat. The 

H 

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98 



MECHANICAL PUDDLING. 



average charge was 6 cwt. 2 qrs. 19$ lb., the average yield 
7 cwt. 2 qrs. 15| lb., or 14*544 percent, gain. The quantity of 
fettling was about 15 cwt. per ton in these experiments, and 
the fettling used was mill-tap cinder or puddlers' tap, melted 
with scrap ball. The author has been favoured by Mr. Crampton 
with the loan of some of the products of his furnace, which are 
on the table, and which show not only iron manipulated in 
various ways, from wire drawn to 18 gauge, and thin tin plates 
to iron plates and rails, but also bath steel and crucible steel 
produced from the same materia). The author is also able to 
give the following tables of breaking strains. 

Table No. 1. 

Showing Tests of Steel produced from Cast Scrap Iron, containing * 87 per cent, 
of Phosphorus. The iron made in Crampton's Furnace ; the steel made from 
it in an open bath ; the tests taken from a 4-ton charge. 



Mark 


Elongation. 


Tons per Square Inch. 


Remark*. 










Specimen. 




Yielding. 1 Breaking. 






1 


•81 


250 


396 ' 


Soft. 




2 


•435 


200 


40-2 


Soft. 




2 


•2 


896 


62-4 


Tempered. 




3 


•858 


172 


40-4 


Soft 




8 


•238 


49 


62-4 


Tempered. 









Railway Bar. 




IB 


145 


41-0 


64-0 


Tempered. 


2R 


•072 


20-4 


42-8 


Soft. 


SB 


•176 


172 


45 6 


Soft. 


O.W. 


•05 


16-6 


376 


Soft. 



Table No. 2. 
Steel made from Swedish Ibon in Cbtjotbles. 


Elongation. 


Tons per Square Inch. 


Remarks. 


Yielding. 


Breaking. 


•866 
•08 
155 


14-4 
32-8 
35-2 


348 
49-8 
59-8 


Soft. 

Low-tempered. 

High-tempered. 



Steel made from Ibon produced from Crampton's Fubnaoe from Oast Ibon 
containing £ per cent, of Phosphorus. 



•185 
025 
145 



13-2 
39-6 
374 



340 
50*8 
59-6 



Soft. 

Low-tempered. 

High-tempered. 



The best proof of the practical value of the Crampton furnace 
is afforded by the fact tnat Mr. Briggs is now putting up twelve 



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MECHANICAL PUDDLING. 99 

3f them at his works, where he has made arrangements to take 
the iron direct from the blast furnace to a heated reservoir, 
from which it is to be carried to the revolver. Messrs. Fox, 
Head, and Co., who are erecting four Crarapton furnaces, have 
arranged to melt the iron in a cupola. In fact it appears to be 
generally admitted that when several furnaces are at work 
the iron should be melted in a separate furnace or cupola. 

The general results of Mr. Crampton's invention clearly 
demonstrate that in the first place slack or small coal can be 
utilized without the production of smoke, and that coal-dust 
and air can be fed automatically, a matter which has sorely 
tried many who have previously endeavoured to effect that 
object. In the next place it is proved that heat of high in- 
tensity can be produced with regularity and economy. Then 
there is the construction of revolving furnaces without brick- 
work, composed of a single chamber in which the gas is produced, 
consumed, and the material treated. The reduction of the 
wear and tear of the furnace by a special water casing and 
an easy mode of fettling are other points; whilst lastly, 
Mr. Crampton has demonstrated the practicability of elimina- 
ting in the puddling furnace phosphorus and sulphur from 
inferior iron to such an extent as to enable it to be converted 
into the best steel, a series of facts which place the invention 
very high in the order of merit, and which the author doubts 
not will ultimately place the inventor in the category of those 
who have advanced the material interests of their country in a 
marked and specific manner. 

conclusion. . 

The present paper has grown to too great a length to admit 
of the author noticing even briefly the metallurgical aspect of 
the subject. He will therefore proceed to state the general 
conclusions to which a consideration of the matter points. The 
question of mechanical puddling, although not a very old one, 
has made rapid progress since it was first mooted. It can 
hardly yet be saia to have received a satisfactory solution in a 
commercial sense in this country, however, for such a solution 
involves the condition that one or more of the systems is capable 
of as general application as the ordinary puddling furnaces. 
This may be the case with some, and the author believes it is ; 
but it has not yet been proved, for want of time. Despite the 
promising results of the Danks furnace at some works in 
America, the proof of its general applicability has not vet been 
established in that country, neither has it been placed beyond 
a doubt in England, although it is believed there is still some 

h2 

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100 MECHANICAL PUDDLING. 

hope for it here, and every endeavour is being made to render 
it successful both at Mr. Heath's works and at the Erimus Works. 
From the latter establishment the author is informed great 
things may be expected, although he has failed to learn what 
these great things may be. In the interests of the iron and 
steel industries, and not less in the interests of the inventor, 
the author hopes it may be so. From ' what he has seen of the 
mechanical details of the Danks furnace, however, he is satisfied 
that unless a radical change is made in the disposition of the 
parts, success cannot attend its continuous working in this 
country. From the statements submitted to the author by Mr. 
Spencer, that gentleman appears to have proved the principle 
or mechanical puddling to be correct at the West Hartlepool 
Ironworks. It now therefore remains for him to show that 
similar results can be obtained under similar conditions else- 
where. Unless a system can be employed with advantage at 
other works besides those at which it has been developed into a 
success under the fostering care of its inventor, it cannot be 
regarded as affording a satisfactory solution to the question of 
mechanical puddling in the broad and liberal sense in which it 
must be treated. Neither Mr. Sellers in America nor Sir John 
Alleyne, with the adapted Siemens revolving furnace at the 
Butterley Works, are yet able to stand the test of practice, 
although both are hopeful that the time is near when they may 
challenge criticism. 

Mr. Grampton has undoubtedly solved the question of me- 
chanical puddling most satisfactorily, and has produced some 
very remarkable results. He, however, still awaits the proof 
of its commercial success — a proof there is no reason to doubt 
will be forthcoming so soon as Mr. Briggs and Messrs. Fox, 
Head, and Co., have got their Grampton plant into practical 
working. But Mr. Grampton has an enormous advantage over 
his competitors in the race for fame. His mechanical ability 
has been brought to bear in designing a machine which embodies 
a degree of mechanical perfectness absent in such other puddling 
furnaces as the author has examined. The conclusion therefore 
is, that although mechanical puddling has been well proved to 
be a practical success, it has nowhere as yet established its claim 
to be considered a thoroughly commercial process. We appear, 
however, to be on the eve of seeing this claim firmly established. 
In the meantime there are appliances which to some extent aid 
the puddler in his heavier duties, and so partially relieve him 
from the severer toils inseparable from hand puddling. Un- 
questionably one of the greatest benefactors of his time, and a 
worthy successor of Cort, will be he who succeeds in rendering 
mechanical puddling a practical and commercial success. 

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( ioi ) 



October 19th, 1874. 

JOHN HENEY ADAMS, Vice-Pbesident, in the Chair. 

MECHANICAL PUDDLING. 

DISCUSSION. 

Mr. Nubsey said that before the discussion was commenced 
he was desirous of making a statement with reference to a 
telegram he had that morning received from Mr. Adam Spencer, 
of Hartlepool, whose puddling furnace he (Mr. Nursey) had 
described in his paper. The telegram was as follows : " I deny 
ever haying made a statement that fifteen shillings per ton 
puddled bar was saved by my puddling machine. Please give 
this correction to-night." As he (Mr. Nursey) had received no 
letter, or other explanation from Mr. Spencer, he had only one 
course to pursue, and that was to read Mr. Spencer's telegram to 
the meeting, and then to explain to the members upon what 
grounds he had made the statement in his paper, to which Mr. 
Spencer took objection. The passage in question was : " Accord- 
ing to Mr. Spencer's statement he has effected a saving of 15*. 
Eer ton of puddled bar in materials and fuel." The reason why 
e had attributed the statement directly to Mr. Spencer was 
because he (Mr. Nursey) believed he was dealing with Mr. 
Spencer's own figures. When applying to Mr. Spencer by 
letter, for information respecting the results of the working of 
bis rotary puddling furnace, he (Mr. Nursey) put a series of ques- 
tions, which he carefully framed as pointedly and as tersely as he 
could, to save all chance of misapprehension. Amongst them 
was the following: "What saving do you prove to make as 
against the old system ? " Mr. Spencer sent no answers to those 
questions, but wrote: "Mr. Price, of the Royal Gun Factories, 
Woolwich, has very many of my results. I have instructed him 
to let you have them, and any other information which he may 
possess about my machine." 

His (Mr. Nursey's) application to Mr. Price elicited a 
prompt response, in which he replied seriatim to all the ques- 
tions. From his letter he (Mr. Nursey) quoted the following : 
" Eeply to question No 1 : Ordinary furnace requires material 
for one ton of puddled bar = 21£ cwt. of pig iron, 4*. per cwt., 
4Z. 6*. ; 24 cwt. of coal, 10s. per ton, 12s. ; 8 cwt. of fettling, 30*. 

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102 MECHANICAL PUDDLING. 

per ton, 12*. ; total, 51. 10*. Spencer's furnace = 19} cwt. of 
pig iron, 4*. per cwt., 3Z. 19*. ; 12 cwt of coal, 10*. per ton, 6*. ; 
7 cwt. of fettling, 30*. per ton, 10a. ; total, 4Z. 15*. ; saving on 
material, 15*. per ton. No allowance is made for the difference 
in labour, which a number of revolvers it is supposed will 
materially reduce." In consequence of Mr. Spencer s statement 
that Mr. Price had very many of his results, he (Mr. Nursev) 
took for granted that the figures above quoted, sent by Mr. 
Price, were given upon the authority of Mr. Spencer, and so, to 
avoid circumlocution, he had directly attributed the statement 
to Mr. Spencer. Mr. Price was present when the paper was 
read, and did not demur to the statement. Whether the 
figures given were correct was a point which must be left for 
Mr. Price and Mr. Spencer to discuss. 

Mr. V. Pendred said that the subject of the paper was a 
very important one, and deserved a very full discussion. There 
were one or two points upon which he wished to obtain a little 
information from Mr. Orampton. One of the first points that 
occurred to him was that the fettling which was required must 
be necessarily used with very considerable waste. The figures 
relating to the Spencer furnace showed, it was true, a distinct 
saving in the quantity of fettling as compared with the ordinary 
furnace, inasmuch as 7 cwt. was used against 8 cwt. ; but this 
statement required some explanation. Fettling was put into 
the puddling furnace for some definite purpose, and it might be 
assumed in the first place that it was applied to protect the 
bottom of the furnace. The old system of sand bottoms had 
been almost entirely abolished, and the furnaces were always 
worked now with cinder bottoms. After the cinder had been 
heated for a considerable time it became a very intractable 
mass, and so far it was tolerably safe. In the case of any 
rotating furnace (supposing it to be a cylinder) it would be 
filled, at the most, to only one-third of its depth with molten 
iron. There would then be two-thirds of the fettling over the 
top of the iron, where it was of no use for the time, as it was 
carried round in the process of rotation. It appeared, as the 
first result of that, that there would be in the furnace at least 
three times as much fettling as was necessary. It might be 
replied that if there was three times as much as was wanted, it 
would last three times as long, but that was a point on which he 
had failed to get information. He did not mean how long it 
would last in an experiment, but how long it would last in 
regular practical working. The fettling in the top of a rotating 
furnace was exposed to a most intense heat, and as all the flame 
worked along the top, if the fettling was at all in a fusible con- 
dition, there would be a continuous tendency for it to run down 

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MECHANICAL PUDDLING. 103 

and leave the brick lining exposed. He could not see how 
paddling was to be carried on without much more fettling in a 
rotating furnace than in an ordinary furnace. 

Another point occurred to him with regard to the rotary 
furnace, though it would not apply so much to that of Mr. 
Crampton as to others. The rotation of a cylindrical vessel, 
smooth inside, and containing fluid, would not necessarily 
impart any motion to the fluid inside the vessel. That might 
be illustrated by the rotation of a tumbler containing water, 
and the same result would be obtained whether the fluid was 
water or molten iron. He believed, however, that that objec- 
tion was in practice to a great extent overcome in the Danks 
furnace, and in others, by the inside surface being made rough 
so as to carry the iron round. Mr. Crampton overcame the 
difficulty by the use of a hexagonal or pentagonal form of 
furnace, but it did not appear to him (Mr. Pendred) that the 
motion which would be imparted to the iron in such a furnace 
would at all resemble the motion given by a puddlers' rabble. 
He could quite understand that, if the furnace was worked on 
the dry system, the iron would be carried round, and no doubt 
when the iron had really approached to nature it would be 
carried round in the furnace ; but it did not appear to him that 
the cylindrical form of furnace was the best, so long as the iron 
was in an intensely fluid state, as in the boiling process. He 
should prefer the form of furnace shown in Fig. 3, in which 
there was a kind of vibratory motion given to the iron, as that 
was more likely to stir it up than the simple rotating furnace. 

It had been stated by Mr. Nureey that Mr. Price, in his 
letter, estimated the saving in fuel by the Spencer furnace at 
12 cwt. of coal, and that 24 cwt. of coal ana 21£ cwt. of pig 
iron was the Quantity used in the ordinary furnace to produce 
a ton of puddled bar. He thought that most practical iron- 
makers would agree with him that where 24 cwt. of coal was 
used, either the furnace must be a very inferior one and the 
system very crude, or the coal must be very bad. Twenty- 
three hundredweight of coal was a very ample allowance, as he 
knew from his own experience ; and he knew that puddling had 
been effected with as little as 18 cwt., and in some cases even 
less than that. At Woolwich a saving of something like 8 cwt. 
of coal, on the ordinary rate of working, had been effected by 
the simple process of widening the grate and reducing its 
length. The influence which the shape of the grate exerted 
on the puddling process, and the quantity of coal needed for it, 
was a very important subject, which he believed had never been 
fully worked out or carried to a point which would convince 
engineers of how much could be done by attention to that 

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104 MECHANICAL PUDDLING. 

matter. It was further stated by Mr. Nursey that in the 
Spencer furnace 19f cwt. of iron was used to 12 cwt. of coal. 
In that statement, however, there were no particulars given as to 
the quality of the coal or the skill of the puddlers employed at 
the ordinary furnace. The fact of 19| cwt. of iron being used to 
make a ton of puddled bar really proved nothing at all in 
favour of the Spencer furnace, because it depended simply on 
the quality of the iron used, and the way in which the gam was 
effected. He had seen nearly a hundredweight of iron in the 
ton gained in two heats by simply using a very rich fettling and 
plenty of mill scale. Therefore, unless the quality of the 
fettling was known, it was not possible to establish a comparison 
between the two furnaces. 

To return to the rotating furnace, there seemed to him to be 
very considerable objections to it. The first objection was the 
great cost of the apparatus, and the large amount of capital 
which was sunk in it. It might be urged, of course, that a 
very large and costly apparatus would give a large return of 
work out. He granted that ; but when repairs were necessary, 
the whole of the machinery and all the work connected with 
the furnace must stand idle, and the capital during that time 
would be unproductive. That was an item which must tell 
against the rotating system by increasing cost, and thus pro- 
moting the difficulty which had existed up to the present time 
in getting a satisfactory commercial result. There was another 
point upon which he would like to ask Mr. Crampton for a little 
information. It was stated that one of the peculiar advantages 
of the Crampton furnace was that dust coal might be used. He 
believed that in any case the coal had to be ground. He recol- 
lected seeing Mr. Urampton's furnace at Woolwich in use three 
or four years ago, not for puddling, but for heating, and at that 
time- all the coal had to be ground between a pair of stones. 
There were three or four pairs of stones running for the purpose 
of supplying the furnace with coal. He would like to know 
the cost of the grinding. In the next place, in consequence of 
the manner in which the air came into the furnace, there was a 
peculiar tendency to a cutting flame which would waste the 
iron. He also wished to know how the variation was effected 
in the draught, and in the quantity of air admitted into the 
furnace as the iron came to nature. That was a very important 
point with regard to the rate of working. 

Mr. Arthdb Bigg said that from what he remembered of 
the paper, it appeared that the fettling had a considerable share 
in some puddling furnaces in producing a decarbonizing effect 
upon the iron, and also in increasing the quantity of iron got 
out of the furnace above the quantity which was put in. 



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MECHANICAL PUDDLING. 105 

Hence one point to be considered was that the material of 
which the fettling consisted should be such that it would assist 
in oxidizing the carbon. Such a material as iron rust or 
scale would do that, and also increase the amount of wrought 
iron delivered by the process. That reaction seemed to be 
carried on in Mr. Crampton's furnace, and all others, except 
where the puddling failed. Another point with regard to all 
those furnaces was, that the character of the flame had some- 
thing to do with the operation, whether the flame be of an 
oxidizing or deoxidizing nature, because the object of the whole 
performance was to take carbon out of the iron to a greater or 
less extent. If a flame was sent into any of those furnaces 
where its own combustion was completed, and the result was 
nothing but hot carbonic acid, then no oxidizing of carbon con- 
tained in the iron could possibly be accomplished by such 
a flame. With regard to the want of success in Mr. Danks' 
furnace, he had learned from a paragraph in the Iron and 
Goal Trades Review, that Mr. Danks' furnace had been a 
signal failure at the works of the Industrial Iron Company; 
but as the other blast furnaces at the same place had a con- 
siderable loss upon them, the test did not appear to be suffi- 
cient ; and at otherplaces, such as Mr. Heath's, Hopkins, Gilkes 
and Co.'s, and the Erimus Company's, Danks' furnace appeared 
to have increased their reputation. But, judging from the 
drawings, Mr. Crampton's furnace was constructed in a more 
scientific manner than its competitors, and it might be that the 
mechanical arrangement of Mr. Danks 9 furnace had something 
to do with its reputed failures. 

Mr. T. E. C rampton said that he thought Mr. Fendred had 
not quite understood the action of the fettling. The fettling on 
the top of the furnace had no practical effect on the iron, 
neither was it, if of good quality, melted to any great extent to 
the injury of the cylinder. The great advantage of having the 
fettling all over the furnace was, that as the cylinder revolved 
new fettling was continually passing underneath the iron, thus 
exposing new surfaces of oxide to the carbon contained in the 
iron, the result being the deoxidation of the fettling, and the 
production therefrom of wrought iron as well as the decarboni- 
zation of the cast iron. The experience which he had had with 
revolving furnaces showed that there was a great gain of 
wrought iron extracted from the fettling itself. In many 
instances the gain had amounted to as much as 25 per cent. ; 
and if 15 cwt. of fettling was used per ton of iron, 14 to 16 per 
cent, excess over the weight of iron charged was obtained, and 
something like half the iron contained in the fettling was thus 
converted into wrought iron. From that point of view, if the 

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106 MECHANICAL PUDDLING. 

fettling were not too expensive, the more fettling used the 
more profitable it would be ; but the using of a large quantity 
was not always convenient. The impression was that if from 
5 to 10 per cent, excess in yield was obtained beyond the 
weight of pig iron charged, there would be an immense gain as 
compared with the ordinary system, in which all the fettling 
was lost, as well as about 8 per cent, of the iron. The assump- 
tion of Mr. Pendred that, on account of the supposed smooth 
action in mechanical puddling, the iron would fail to be 

Euddled as effectively as in hand puddling, was not borne out 
y practice ; and if Mr. Pendred would accompany him to 
Woolwich he would show him that the puddling action was 
absolutely perfect, the effect being that a 10-cwt. ball was 
made homogeneous in quality throughout. 

The action of the melted iron in the revolving furnace was 
similar to that represented by Mr. Pendred in a tumbler of 
water ; but in certain stages as the fettling passed underneath 
the iron, which remained comparatively stationary, the oxygen 
in the fettling came in contact with the carbon in the iron, 
thus creating reactions which produced the circulation re- 
quired. At the period when the iron began to come to what 
was called " nature," the furnace, if it was perfectly smooth, 
might pass under the granulated iron without moving it ; but 
that was almost impracticable from the nature of things, as 
the process of fettling would always leave rough surfaces. It 
was almost impossible in a revolving furnace to produce a 
puddle ball that was not homogeneous. Mr. Spencer tried the 
rhomboidal furnace originally, and after patenting it disclaimed 
it — Mr. Warren having previously patented it ; but Mr. Spencer 
obtained no better result from the iron being canted about 
from one end to the other than he did in his present furnace, 
which was square. Mr. Spencer produced extraordinary 
results, and he (Mr. Crampton) had seen 28 cwt. of iron in one 
mass in that furnace at the same time. The difficulty which 
he as an engineer saw in that furnace was that, like Tooth's 
and Danks', it was not scientifically constructed, and it could 
not be expected to last or keep in order, as it was not easy, if 
indeed practicable, to apply water for the purpose of pre- 
serving the outside at a regular temperature and consequently 
true in form, thereby necessitating great power for its manipu- 
lation as well as excessive wear and tear. He (Mr. Crampton) 
might observe that at Hackney, before Mr. Menelaus took up 
the matter, Messrs. Tooth and Yates obtained in their experi- 
ments a yield of 10 per cent, more wrought iron than pig 
charged ; but at that period the puddled iron was not good, for 
they had not, as he believed, a good kind of fettling. They 

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MECHANICAL PUDDLING. 107 

used a bad lining, and the silica spoilt the iron ; but still an 
excess was produced. 

Mr. Tooth had suggested two very important matters, and 
included them in his patent. One was the movable flue, similar 
to that now employed by Mr. Danks, which remained sta- 
tionary whilst the furnace itself revolved, and which was with- 
drawn for the purpose of extracting the puddle ball. Mr. 
Tooth pointed that out in his description and drawings, showing 
that the movable flue might be either slid away on rollers or 
swung away on a pivot, or it might be opened like a door. 
Mr. Danks afterwards published the same thing ; but Mr. Tooth 
did one thing more, he knew the value and importance of 
keeping the furnace cool outside. It could not be expected 
that a true form of furnace could be retained when there was a 
heat of from 3000° to 4000° inside unless the outside was kept 
at one temperature. Mr. Tooth therefore suggested making a 
double casing on the outside of the furnace for the purpose of 
holding water ; but unfortunately he could not get the water 
into it effectually. In his patent he also shadowed forth the 
use of a loose casing placed outside the fixed casing of the fur- 
nace ; and Mr. Danks in his patent mentioned the same thing. 
But according to Mr. Tooth's plan, the water failed to cool the 
ends of the furnace, and the heat coming in contact with the 
fettling protecting those ends melted it and exposed the plate, 
thus causing serious inconvenience. 

The essence of his (Mr. Crampton's) arrangement was that a 
perfect circulation of water was maintained over the whole of the 
furnace, the effect being that the wearing face on the exit end 
of the furnace, which was the most important part to keep cool, 
fettled itself, and that end had never been touched since the 
furnace had been at work. The furnace by these means re- 
tained its true shape, and that was one reason why it was 
supposed to last, and it would last. 

With regard to the quantity of fuel, Mr. Pendred made a 
very just remark, and one which was not generally considered ; 
it related to reducing the length of the fire-grate. The nearer 
the fire to the work to be done the better was the effect, for it 
was well known that heat, like light, decreased as the square 
of the distance. The most economical result was obtained 
when the combustion of all the fuel took place in direct con- 
tact with the work, which was the case in his furnace, all other 
revolving furnaces producing the gases in a separate chamber, 
consequently consuming much more fuel. When the cubic 
capacity to be heated was reduced by one-half, the consumption 
of fuel would be reduced to nearly the same extent. Another 
observation might be made bearing on that point. He found 

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108 MECHANICAL PUDDLING. 

practically that in the same furnace the same quantity of fuel 
was required per charge, whether 5 cwt. or 10 cwt, charges 
were being puddled. 

Mr. Pendred had called attention to the grinding of the 
coal. That was, however, a secondary consideration. He was 
under a wrong impression as to the number of stones employed 
at Woolwich for the purpose. They never had more than one 
pair of 3 ft. 6 in. stones in use for grinding coal, and there was 
no question that with ordinary skill and attention the coal 
might be ground in large quantities for Is. per ton. 

One important feature in all those metallurgical operations 
was the maintenance of a high temperature of uniform quality. 
What was meant by all the mechanical arrangements for 
stoking, but an endeavour to bring the oxygen and the carbon 
together in proper proportions ? The gas furnace was sup- 
posed by some to do that ; but it was not effectual, the reason 
being that the operator did not have the two main elements 
under his absolute control. There should be no exterior 
circumstances to interfere with the operation, such as a variation 
in the draught in the chimneys or in the quality of the gas 
supplied, and those things disturbed the proper equilibrium 
between the air and the coal ; and unless the attendant on the 
furnace had the absolute control of those elements he never 
could satisfactorily produce the desired results. It was for 
that reason that he (Mr. Crampton) came to the conclusion 
that the only way to achieve the result was to powder the fuel, 
and thus to obtain a homogeneous material which enabled a 
machine to be constructed for feeding the fuel in a regular 
manner. The feeding machine which he had at Woolwich had 
been worked for four years without requiring repair, and he did 
not believe that it had been looked into half-a-dozen times 
during that period. If the furnace from any cause ceased 
work for a week, the feeder needed no attention when the work 
was resumed. The fuel could be turned on just as a gaslight 
was, and there would be no doubt about its operation. In fact, 
it was absolutely perfect — at least he could not see how to 
improve it. The supply of coal was effected by means of a pair 
of rollers. He had on many occasions welded 70 tons of 
wrought scrap iron without ever touching the air or the coal, 
and he was satisfied that he could go on working the furnace 
for a year without the air and fuel varying 5 per cent. A most 
important point was the oxidation of the iron. In ordinary 
puddling a regular flame could not be ensured; and in one 
stage of the process, if the fires were forced the iron would be 
oxidized, causing considerable loss. 

In his process he practically eliminated all the phosphorus 

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MECHANICAL PUDDLING. 109 

and sulphur ; at least he had as yet never failed to do so what- 
ever the quality of the pig used. On the table was a piece of 
iron made from Cleveland pig, containing 1 *3 percent, of phos- 
phorus, steel having been produced from it, and worked into tools 
of good quality. Those results could be obtained because the 
phosphorus and the sulphur were practically eliminated, and 
that was .accomplished by the regularity of the temperature 
and by the even quality of the flame itself. In common pud- 
dling, when the ball was finished the puddler waited until 
it was sufficiently hot to be withdrawn, which was indicated by 
its brilliant white appearance. That whiteness meant oxida- 
tion and waste of iron. In his (Mr. Orampton's) process they 
did not necessarily touch the air or fuel throughout the entire 
operation, and there was never a scintilla of white upon the 
ball, and consequently no sign of oxidation. Those elements, 
viz. high temperature and regularity, enabled the last incre- 
ment of phospnorus to be eliminated at the end of the opera- 
tion — at least he thought that must be the cause. 

Mr. Pendred asked if he was to understand that Mr. Cramp- 
ton worked with a reducing flame from the first to the last in 
the process of puddling ? 

Mr. Cbampton said that as a rule such was the case, but it 
was not always wise to do so. The best plan was to keep as 
near to theory as possible. He had the power to feed twelve 
pounds of air to a pound of fuel, which were the theoretical 
quantities ; but he generally worked with a little in excess, say 
about 10 or 15 per cent. In the ordinary furnace the air 
varied from 50 per cent too little to 100 per cent, too much, 
and it could therefore readily be understood how he obtained 
his high and regular temperature. In fact, he could produce 
either an oxidizing, neutral, or carbonizing flame at will. 

Mr. Pendred said that the next question which he wished to 
ask was with regard to what Mr. Crampton called the loss of 
heat, which arose through the combustion taking place at a 
distance from the material which was to be heated. He 
(Mr. Pendred) had recently had direct confirmation of the fact 
that heat was lost in such a case; but he wished to know 
whether Mr. Crampton could throw any light upon the question 
of what became of it ? 

Mr. Crampton said that that was a question which he could 
not very well define. He knew that it was a fact if they made 
a fire outside a boiler, and took the gases underneath, there was 
an immense loss of heat compared with the burning of the fuel 
in contact with the boiler. He had certain views on that 
subject ; it was not properly under discussion that night He 
should like it to be understood with regard to the flame, 

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110 MECHANICAL PUDDLING. 

that he could puddle with the same flame throughout, from 
commencing to melt the iron to taking out the finished ball, 
without touching the regulators, and still get out from 12 to 20 
per cent, excess. It was because there was no free oxygen to 
cut the iron. The old notion was that the excess of oxygen in 
the air effected the puddling; but in his furnace there was 
practically not sufficient to effect the object, but that contained 
in the fettling did the work, and did it in a better manner, for 
the pure oxygen of the fettling, coming into contact with the 
pure carbon in the iron, produced a higher temperature during 
combustion than when atmospheric oxygen was employed. 

Mr. Pendred said that in that case it was a distinctly 
different process. 

Mr. Cbampton said that there were many reasons which 
enabled him to produce the results. The high temperature 
was not diluted by an excess of atmospheric air, and that fact 
gave rise to a regularity of action which appeared to take out 
the last increment of. phosphorus. It had been thought that it % 
was essential to employ at certain stages of puddling a low* 
carbonizing and at others a high oxidizing flame ; but he pre- 
ferred to nave a high temperature with a neutral flame 
throughout the whole operation, and whatever quality of flame 
was found best under varied conditions he had it in his power 
to produce. 

Mr. Nurset, in rising to reply upon the discussion, said that 
he had really no remarks to offer, as the points raised by Mr. 
Pendred had been fully and ably answered by Mr. Crampton. 
Nothing therefore remained for him to do but to thank the 
members for their attention to his paper, and for their presence 
and assistance in the discussion of a subject which was of the 
highest importance in connection with the iron and steel in- 
dustries of the whole world. 



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PLATE 2 



Fig . 10. 




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( 111 ) 



October 19*A, 1874. 

JOHN HENEY ADAMS, Vice-President, in the Chaib> 

THE ACTION OF MARINE WOEMS AND THE 
REMEDIES APPLIED IN THE HARBOUR 
OF SAN FRANCISCO, CALIFORNIA. 

By John Blaokbourn. 

In bringing before the Society a subject which has so often 
been discussed, and one that has been the cause of many 
interesting experiments both at home and abroad, the author 
wishes it to be clearly understood that although many of his 
observations differ materially from those of other engineers, 
the locality may perhaps in a great measure be the cause for 
what otherwise might appear direct contradiction. The object 
of the author is not to oring forward any new theories, but to 
give the results of his own observations, and to invite members 
to place their practical experiences side by side, no matter 
how unimportant it may appear to them, in order that more 
knowledge may be gained of the destructive action of the 
marine worms and of the remedies that may be applied. 
Numbers of patents have been taken out, but none have 
proved themselves of permanent value and to answer their 

Surpose for more than a few months, and certainly not fri- 
lling what is claimed for them. The author is enabled to 
place before the Society his experience whilst in charge of 
works in the harbour of San Francisco, California. On rebuild- 
ing a wharf he had occasion to remove about 300 pies, most of 
which had been driven at intervals since 1859. The original 
piles were covered with copper sheathing, the wharf had been 
rebuilt two or three times, and when the old piles were not in 
the way of the new ones they had been left standing. Before 
1870 tne piles used in the repairs were non-preserved Oregon 
fir with the bark on. In September, 1870, and in the spring of 



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112 ACTION OF MAEINE WOBMS. 

1872, Oregon fir piles, preserved by the Kobins process, were 
used. This process and the conditions of the various piles will 
be described separately. Timber structures in the harbour of 
San Francisco are exposed to the Teredo navalis and Limnoria 
terebrans ; these worms appear to work independently of each 
other, and to work all the year round, rendering it necessary to 
rebuild every two or three years. 

The Teredo navalis, where possible, enters the timber at or 
near, but always above, the ground line. The worm does not 
appear to enter above ordinary low water, but inside the pile it 
has been traced up to 1 foot 10 inches above low-water datum, 
and it has been found to work down 2 feet 5 inches below the 
ground. Floating timber is not exempt from its ravages. All 
that is visible on the outer surface of the timber is a small 
round hole, about one-sixteenth of an inch in diameter. When 
entered, the worm at once begins to enlarge itself, at first funnel- 
shaped, and when folly formed it increases in diameter very 
gradually. The head, which is a perfect auger, is of the 
ordinary sea-shell substance, in two parts, working on a hinge. 
Like its gelatinous body, the head completely fills the cavity 
bored. The tail is flat and double, and is protected by a thin 
shell covering ; the end of it can at will be projected out of the 
hole at which the worm entered. The author has remarked 
that the tail is always near the entrance, and that by it the 
worm has that communication with the water without which it 
cannot live. As it grows it bores to make room for its body, 
which has been found to reach 3 feet 6 inches long and £ inch 
in diameter. One teredo will never enter the hole of another, 
but will work round it, leaving a very thin partition between. 
These worms never touch the knots, always avoiding them, 
sometimes by the most complicated twists, especially when 
several worms are near together. The Teredo navalis has no 
visible means of locomotion. Its power to bore is centred in 
its head ; there are no bones in the body. When taken out of 
the water it soon dies, and its body dries into a very thin skin. 
It has often been stated that the Teredo navalis will not attack 
timber with the bark on. The author's experience, however, 
proves otherwise. He finds that it does attack the bark, but 
that most of the worms die before they have succeeded in pene- 
trating it. That many do get through has been clearly proved. 
The author is satisfied that to a great extent the bark is a pre- 
servative ; but when once it is damaged, the timber presents no 
obstacle to the worm, and having once entered the timber, the 
worm never works out of it. 

The Limnoria terebrans, according to Mr. T. J. Arnold, 



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ACTION OF MARINE WOBMS. 113 

Engineer to the Board of State Harbour Commissioners, has 
only recently made its appearance in the bay of San Francisco. 
The author, on examining some old non-preserved piles removed 
from the wharf in September, 1870, found them to be consider- 
ably attacked. The Limnoria terebrans is a small worm about 
one-fifth of an inch long, armed on the head with a pair of 
strong mandibles, with which it bores. When touched it will 
roll itself up into a ball. These worms attack the timber from 
the outside. They are gregarious in working, and appear to 
radiate from a common centre, working across the grain, slightly 
up and down — not horizontal. They never touch knots, but 
work round them. They have been traced from the ground 
line to about mean high water. They will cut a pile completely 
through, leaving the upper part hanging to the cap. After 
carefully inspecting a large number of piles the author has not 
found the Limnoria terebrans to touch the bark, but where it is 
damaged they will enter the timber under it. They will attack 
floating timlJer, and seem to prefer working near the shore, and 
will at times follow down the teredo holes after that worm is 
dead. 

Copper-covered Oregon fir piles were driven in December, 
1859. The sheeting was about 26 B.W.G., fastened on by com- 
posite nails. The copper was carried down 2 feet under the 
surface of the ground, and up to just above low-water datum. 
Above this the bark was left on, but had in time dropped off 
by the action of the waves. Before the pile shown on the 
diagram was drawn the Teredo navalis could not be discovered 
in consequence of the attacks made by the Limnoria terebrans, 
which at 2 feet 4 inches above the copper had nearly eaten the 
pile through. For convenience of drawing the pile was cut off 
at 2 feet 4 inches above the copper, and here there was no sign 
of the Teredo navalis, but on being split down the centre it was 
found that the teredo had entered just above the copper, and 
had worked down underneath the copper for 8 feet, and there 
abruptly turned upwards. The pile was here completely honey- 
combed, but below this it was as sound as when driven fourteen 
years ago, excepting at places where the copper had worn away 
and the Limnoria terebrans had entered, but only for a slight 
depth. At these places the teredo had not attacked the piles. 
The mistake made was in not carrying the copper sufficiently 
high. Had it been carried up to extreme high water the Teredo 
navalis would not have entered. The object then sought for 
would have been attained, for at that time the Lvnrnoria 
terebrans was not known to exist in the harbour. Many of 
these copper-covered piles have lasted fourteen years, and the 



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114 ACTION OF MARINE WORMS. 

author was able to use several when building the new wharf in 
September, 1873. 

The unpreserved piles driven in 1867, many of which still 
remain standing, were very badly attacked by both worms ; but 
some of them were not much worse than the three-year-old 
preserved piles. The bark had originally been left on, but 
with the action of the water had dropped off. The author may 
here state that the experiment had been tried of driving small 
nails with large heads close together over those portions of the 
timber from which the bark had been removed, but this plan 
failed to keep the worms from entering the timber. 

The Robins process of preserving piles, as practised in San 
Francisco, is to remove the bark from the piles, when about 
forty are placed on cars and run into a t*nk which is 80 feet 
long, 14 feet high, and 11 feet wide. The doors are closed, and 
steam is let into the tank at a low pressure in order to wash out 
from the wood the albumen and any fermentative deposits left 
in it by the sap of the tree. After. this the wood is dried by 
means of a steam coil and ventilation. It is then ready to 
receive the oleaginous vapours, which are generated from coal- 
tar placed in a closed still capable of holding 2000 gallons. 
The first products of the tar, viz. naphtha and ammoniacal 
water, are allowed to pass off separately. When the ther- 
mometer at the top of the still indicates 220° the vapours are 
turned on the wood and the still kept running until a heat of 
420° is reached. The firing under the still now ceases, but the 
still is allowed to remain connected with the tank for ten or 
twelve hours, when the wood is ready for use. The patentees 
claim that the piles are not at first entirely impregnated, yet 
that the surfaces have received sufficient to prevent the worms 
attacking, and that it is only a question of time. How long 
they do not state. After three years the author has noticed a 
faint odour in the centre of the piles, but the surface, which is 
claimed to be thoroughly treated, does not keep off either worm. 

The preserved piles, which had been driven in the wharf 
eighteen months, were considerably attacked by both the Teredo 
navaUi and the Limnaria terebrans. The teredo had worked 
down below the ground 13 inches, and many of the worms were 
over 2 feet long, showing that they had been in the timber for 
some months. The preserved piles driven three years ago were 
completely honeycombed, and were eaten away at the ground 
level by the Teredo navalis, which had worked down 2 feet 
5 inches below the ground ; here were worms 3 feet long, and 
$ inch in diameter. These piles were also attacked by the 
Limnoria terebrans, and were eaten through just about the 



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ACTION OF MABINE WORMS, 115 

ground line. They were constantly being washed away by the 
ordinary tidal currents, and they were very little better than 
the non-preserved piles driven in 1867. The worms actually 
appear to have attacked these preserved piles in preference to 
the non-preserved. From a specimen cut off of a three-year- 
old pile, it could be seen how near the surface the teredo had 
worked ; by holding it up the light shone through it, and yet 
this is the very part of the timber claimed by the patentees as 
being effectually preserved, clearly proving that the worms will 
attack timber treated by the Robins process. What then can 
prevent the worms from attacking the centre of the piles? 
The author has used timber preserved by this process for 
mortar platforms, and in dressing it found that the sap was not 
driven out of it, but had rotted the centre. It is also claimed 
that timber treated by this process will neither shrink nor 
swell ; but with magazine doors made from it, in summer the 
joints would open a full £ inch, and would draw the lock out of 

J)lace, in winter the doors could not be opened, and this after 
bur coats of paint. 
The conclusions at which the author arrives are : 

(1) That when repairing timber structures all timber 
attacked by the marine worms, especially the Linmoria tere- 
brans, should be removed and not allowed to remain alongside 
the new work, as the worms migrate from the old to the new, 
that part of a pile nearest the old being always the first to be 
attacked; the author has found that the piles standing by 
themselves have always been attacked to a less extent than 
where several piles were together. 

(2) That many of the coppered piles after being driven 
fourteen years were in a good state of preservation, and the 
author has used several of them in the new wharf; that the 
copper must be carried from about 1 foot under the ground 
line to extreme high water ; by doing so the life of the pile 
would be at least twenty years ; that where portions of the 
metal had been worn off by the action of the water, the teredo 
had not been found to attack, and the Limnoria terebrans, 
although it had entered the timber, had done so only to a 
slight extent ; that the objections to copper are the liability to 
be stolen or damaged, ana that the cost, although at first heavy, 
will prove the cheapest in the end, especially in a country 
where labour is dear. 

(3) That the bark where not damaged afforded a certain 
amount of protection from the worms, though not effectual. 

(4) That the Robins process has proved a complete failure 
Tort Point ; that by the size of the Teredo navalis found in 

I 2 



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atFo 



116 ACTION OF MARINE WORMS. 

the eighteen-months piles, the timber must have been attacked 
in less than a year, and that in less than three years the piles 
were completely destroyed. 

DISCUSSION. 

Air. P. F. Nubsey said that in Australia there was a very 
hard kind of wood called Jarrah Jarrah timber, and which was 
sometimes known by the name of iron wood. That wood 
appeared to be specially adapted for piling, and for structures 
subject to tidal action, inasmuch as it was not liable to the 
attacks of the teredo, or other worms. That was accounted for 
on two grounds ; in the first place, the timber was extremely 
hard and dense, and hence it was difficult for the worms to 
penetrate it ; and, in the next place, it was believed that it 
contained a colouring matter which was objectionable to them. 
It might be, however, that the extreme hardness of the material 
and its great weight formed objections to its use under some 
circumstances, by reason of the cost both of transport and of 
working up. It had, however, to his knowledge been used in 
pier work, and had never been attacked by the worms. 

Mr. G. 6. Andr£ said, with regard to the statement in the 
paper that covering with nails failed to keep out the worms, 
that he had always found that method prove very effectual. 

Mr. V. Pbndred said that some four years ago he had 
brought under his notice a proposal for protecting wood by 
means of square-headed nails, the heads of which fitted pre- 
cisely together without leaving uncovered places. It had been 
found that when round-headed nails were used the worms 
entered the wood at the interstices between the heads of the 
nails. It appeared to him that it would be cheaper than 
covering the piles with copper to cover them with nails made 
of a good quality of iron, and having their heads made to fit the 
convexity of the piles. 

Mr. J. W. Wilson, jun., said that he believed that some 
square-headed wrought-iron nails were employed at Heme Bay, 
but they were liable to fall off, and when one had fallen off 
the worm effected an entrance, and the rest were practically 
useless. 

Mr. Pendred said he thought that round-headed nails were 
used at Heme Bay. 

The President asked Mr. Wilson whether he meant that the 
heads fell off the shanks, or that the nails came wholly out of 
the wood. 

Mr. Wilson said that either result might happen. The 



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ACTION OF MARINE WORMS. 117 

heads of the nails, which were about 1J inch square, with 
short shanks, corroded together at the edges, ana a compa- 
ratively slight blow was required to knock them out of the 
wood. Of course, piles were liable to receive heavy shocks. 

Mr. Andr£ said that the experience of which he had spoken 
did not relate to piles but to dock gates. The nails were 
square-headed, and they were driven into the wood in such a 
manner that it would take a considerable blow to knock them 
off. The wood itself was very hard, and the timber had lasted 
well. When he saw it it had been fixed for eight or nine 
years, and it was then in a perfect state of preservation. He 
did not see why a covering of square-headed nails should not be 
as effective as a sheathing of copper, for there was practically 
an unbroken surface. He had seen square-headed nails used 
frequently in France, but he had never seen round-headed nails 
so used. 

Mr. Frederick Braby said that one of the most interesting 
points seemed to be that the Teredo navalis and the Limnoria 
terebrans did not touch the knots of the wood. There might be 
something in the chemical composition of the knots to repel 
those insects. If so, it might not be very difficult to charge 
the wood with the material of which the knots were composed. 
Nails might be convenient where copper sheathing could not be 
obtained; but he did not see any advantage as regarded 
expense in covering the surface with square-headed nails 
instead of copper sheathing, unless the nails were of some 
cheaper metal than copper. No. 26 B.W.Gr. copper was very 
thin, and the heads of tne nails would scarcely be thinner than 
that. Perhaps it might be found to be advantageous to use 
zinc for the sheathing, as on account of the lower price of that 
metal as compared with copper a greater thickness might be 
used for that purpose. 

Mr. Arthur ICigg asked whether any member present could 
describe the tool with which the insects bored their way into 
the wood, for it would be interesting to know its construction. 
It appeared as if the insects avoided knots on account of their 
hardness. Mr. Nursey had in fact stated that they refrained 
from boring into iron wood for that reason. 

The President observed that the author of the paper 
referred to one of the insects having a head like an auger ; but 
that could hardly be, as it would not turn completely round. 

Mr. Andr£, in reply to a question from a member, said that 
the nails to which he had referred were made of iron. 

The President said that it appeared to him scarcely pos- 
sible that the workmen would get the heads of all the nails 



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118 ACTION OF MARINE WORMS. 

quite close together, because they would try to avoid over- 
lapping the nail heads, and thus a space sufficient for the 
entrance of the insects might be unintentionally left here and 
there. It seemed, however, that one insect would not follow in 
the hole which had been made by another, so that at the worst 
only a few isolated insects would enter the piles if covered 
with nails. 



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,Lhtbr-iiii*if6ap 



3 YEARS OLD 
PRESERVED. 




1 






pfiii 



^"Erebrans traced, 1d tkUZtwl. 



T*pr<L\Qqc^iw.t£ihi4 LeveL. 




h/Shee 



I Span jXanclari & New \ark- 



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(119 ) 



November 2nd, 1874. 

JOHN HENRY ADAMS, Vice-President, in the Chair. 

TRAMWAY ROLLING STOCK, AND STEAM 
IN CONNECTION THEREWITH. 

By Charles C. Cramp. 

In introducing the subject of the present paper to the Society 
of Engineers, it has been the ahthor's endeavour to avoid repe- 
tition of that which is common knowledge ; he feels, however, 
that it is necessary to go somewhat into the past, so that the 
members may have brought to their minds past failures, which 
have been due not so much to want of constructive skill in the 
engineers, as to the concurrent circumstances of public prejudice 
ana bad roads. It will, however, be sufficient to keep to com- 
paratively modern history with respect to the application of 
steam to the propulsion of carriages. 

It would seem that the first idea of a steam-propelled car- 
riage emanated from Dr. Robinson, then a student of Glasgow, 
and from whom Dr. Watt received the suggestion. It appears, 
however, that Cugnot, a Frenchman, was the first to carry the 
idea out in practice. In 1770 he constructed a carriage pro- 
pelled by steam for the conveyance of cannon. The boiler and 
engine were carried on a single wheel, which took a bearing on 
the fore part of the carriage, the load being carried on the two 
hinder ones. The carriage framing was in two parts, and 
centred on a pivot for convenience in guiding the machine. 
An angle so small as 20° could be turned by this carriage. Dr. 
Watt, in 1784, patented a method of applying steam to the pro- 
pulsion of carriages, but he does not appear to have carried his 
method into practice. 

In 1785 Murdoch constructed a model steam carriage; the 
boiler was of copper, the flue running obliquely through it, the 
heat being obtained from a spirit lamp. This small engine, 
15 inches high, attained a speed of 8 miles an hour. 

In 1786 Oliver Evans, an American, experimented in the 
same direction ; he petitioned the Legislature of Philadelphia 



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120 TRAMWAY ROLLING STOCK, 

for exclusive right to propel wagons by steam, and was thought 
mad for his suggestion. However, in 1787 the Legislature of 
Maryland granted him the right for fourteen years, in the year 
1804 he built a dredging machine fitted with an engine of 
5 horse-power ; he successfully moved this vessel on a frame- 
work having wooden wheels, by the power of his own engines, a 
distance of 1 J mile. In the year 1787 William Symington — 
who has been accredited by some as the first inventor of the 
steam carriage — constructed a model of his carriage propelled 
by a low-pressure condensing engine. The success of the work- 
ing model was so great that he determined to put it into prac- 
tice, but the difficulties he met with were so great that he had 
reluctantly to abandon the idea. But the most ingenious and 
successful attempts were made by Trevithick and Vivian, who 
obtained a patent in the year 1802 for their invention ; in the 
following year they constructed a locomotive carriage, which 
ran for many days through the streets of London at a rate of 
9 miles an hour. In 1805 they took an improved tramway 
locomotive to the Wylam Colliery, and explained its construc- 
tion to George Stephenson. Later, in 1808, Trevithick con- 
structed a tramroad and locomotive carriage which travelled 
at the rate of 12 miles an hour; but he experienced great 
difficulty in the construction of the road. This engine was the 
first to which was attached a carriage used for hire. Trevithick 
came to the conclusion that the forerunner of road steamers 
should be improvements in the construction of roads. 

In 1812 Mr. Brunton patented an invention, the propulsion 
being effected by means of levers similar to the legs of a horse. 
The first steam passenger carriage in actual use in this country 
was that patented by Julius Griffiths, of Brompton, Middlesex. 
This carriage proved unsuccessful on account of an insufficient 
generation of steam. 

In 1824 Burstall and Hill patented a steam carriage, which 
failed through the bad construction of the boilers. In 1824 
also Mr. David Gordon took out a patent, based upon that of 
Brunton's. This machine had six hollow legs, with a regu- 
lating spring in each for lengthening or shortening purposes, so 
that the legs in any case would act upon the road. In 1825 
Mr. Gurney produced a steam carriage propelled by legfi^ but 
after many experiments, in which a combination of driving 
wheels and levers was resorted to, the legs were abandoned as 
producing no effective increase of power. .In 1826 Mr. Samuel 
mown constructed a gas engine, and fitted it to a carriage, which 
ascended Shooter's Hill, in presence of numerous spectators. 
The cause of failure in this instance was the expense of work- 



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AND STEAM IN CONNECTION THEREWITH. 121 

in^. In 1828 Gurney further improved his steam carriage ; 
this carriage was propelled by one wheel only, the engineers 
were completely covered in, and it had the appearance of an 
ordinary stage coach, as will be seen on reference to Fig. 1. It 
ran experimentally for a space of eighteen months, during which 
time it traversed the whole of the hills between Cranford 
Bridge and Bath. Steam carriages constructed on Gurney's 

Principle have been known to run from 20 to 26 miles per 
our. 

In 1829 Sir James Anderson and Mr. W. H. James made a 
journey in one of their carriages loaded with fifteen passengers 
through Epping Forest, over a roughly gravelled road,. with a 
speed varying from 12 to 15 miles per hour. The carriage in 
which the journey was performed was a four-wheeled one, 
weighing nearly 3 tons, propelled by the hind wheels. The 
boiler was composed of common welded gas tubes, but the pres- 
sure of steam, viz. 300 lb. to the square inch, opened some of 
the seams. The engine had two cylinders of only 3£ inches in 
diameter. 

It was about this time that Mr. Walter Hancock constructed 
a three-wheeled coach to carry four passengers, and named it 
the 'Infant.' This first carriage of his construction, though 
defective, accomplished the most unexpected task, making 
journeys from his works at Stratford to Croydon and Hounslow, 
and always returning the same day. 

In 1831 Mr. Hancock commenced running his coach, the 
* Infant,' from Stratford to London, and with such success that 
he made the succeeding engines on the same model. The 
great features of this coach were the economical arrangement 
of the engines, a novel and remarkably efficient boiler, inverted 
oscillating cylinders, an air-tight ashpit, so that the effective 
power of the blast could be utilized to the utmost ; the destruc- 
tion of the waste steam by decomposition. The wheels used 
were of a very ingenious construction, very light and strong, 
and admitting of easy tepair. In 1832 the 'Infant' ran be- 
tween Faddington and the City with the greatest success ; in 
that year he built the ' Era,' for use on the road from London 
to Greenwich. On the 31st October, 1832, Mr. Hancock, accom- 
panied by scientific gentlemen, started with the 'Infant' for 
Brighton, with a speed of 9 miles an hour ; arriving at Bed 
Hill, a point where that season's coaches required six horses, 
they made the ascent at the rate of 6 miles an hour. The diffi- 
culty experienced was an insufficiency of coke and water ; they 
had therefore to complete the journey the next day. 

On the return journey one mile was made uphill at the rate 



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122 TRAMWAY ROLLING STOCK, 

of 17 miles per hour, exclusive of stoppages. The ' Infant * ran 
to Brighton in six hoars. In 1833 Mr. Hancock built the 
' Enterprise/ to run from Paddington to the City, for a com- 

Kny — the journey was always performed under the hoar. Mr. 
uicock was summoned before the magistrate for not making 
the carriage under a hackney coach plate, and was fined in 
consequence. About the end. of the Rammer 1833 he com- 
pleted another steam coach, the * Autopsy/ shown in Fig. 2, 
with which he performed a journey to Brighton. Beturning 
the following day, he passed over London Bridge and through 
the City at midday, proving the facility and ease with which the 
movements of such a carriage can be accommodated to all 
the accidents to which it might be liable in the most crowded 
thoroughfares. In the month of October, for nearly four weeks, 
the ' Autopsy ' ran for hire between Finsbury Square and Pen- 
ton ville : it ran for that time without accident or intermission. 
In the spring of 1831 Mr. Hancock received an order to con- 
struct a steam drag for a gentleman in Vienna. This drag 
underwent a variety of trials. The greatest speed it obtained 
was 14 miles an hour on the level, and 9 miles an hour up- 
hill, loaded with sixteen passengers. In the same year Mr. 
Hancock completed the * Era, 9 and on the 18th of August, 
1834, he commenced running his two coaches between the 
City, Moorgate Street, and Paddington, and continued to run 
until November, carrying during that period 4000 passengers. 
In the same year, at the request of several gentlemen, he 
shipped one of his carriages to Dublin, where it ran with the 
greatest success. On one occasion it ran three times round St. 
Stephen's Green at the rate of 18 miles an hour. This appears 
to have been the highest rate of velocity he ever obtained from 
any of his steam carriages. 

In 1836 he put all his carriages on the Paddington road, 
and ran them daily for upwards of five months, during which 
time they ran 4200 miles, made 525 trips from the City 
to Islington and back, 143 to Paddington and back, 44 to 
Stratford and back, and passed through the City about 200 
times. The fare between Paddington and the City was one 
shilling. 

It is the author's opinion that Mr. Walter Hancock between 
1830 and 1837 did more to show what was practicable on 
common roads with steam carriages than any other person 
before or since. 

The boiler he used was very simple and efficient. It was 
2 feet square and 3 feet high, and was made with flat chambers 
2 inches wide and i inch thick, covered with bosses, arranged 



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AND STEAM IN CONNECTION THEREWITH. 123 

in such a manner that the bosses of one chamber touched the 
bosses of the neighbouring chamber, thus forming abutments, 
and at the same time increasing the heating surface. The 
outer pressure was taken by two strong wrought-iron plates 
firmly secured together by cross bolts and girders. Instead of 
placing the driving wheels direct upon the crank shaft, he 
placed them upon a separate straight axle, driven from the 
crank shaft, by means of a chain and pitched pulley. The 
relative distance between the two shafts was always, notwith- 
standing any rise and fall of the carriage, preserved by hori- 
zontal radius rods — that enabled him to use perfect carriage 
springs for the driving wheels, without interfering with the 
action of the crank shaft of the engine. When the coach was 
not running, all that was necessary was to throw out the clutch 
from the chain pulley, and then the engine could be worked, as 
might be desired, for the purpose of pumping or of urging the 
fire by the fan blast The engine was steered by a pinion and 
chain working a common lock carriage. The fire-bars are also 
worthy of notice : two sets coupled up were provided, and so 
arranged that when one set was withdrawn the other clear set 
could be put in, and when the clinkers were scaled off the first 
set was ready for use again. 

Mr. Hancock had so far proved that heavy carriages are not 
necessary for quick passenger traffic. He also was one of the 
first to cfiscover that the way to keep the boiler from priming 
was to cause the steam to come through an extremely small 
steam pipe. The waste steam was blown into a box, and passed 
from there into the fire in a finely-divided state, and from there 
it escaped quietly. In the year 1831 Sir Charles Dance ran a 
steam carriage between Gloucester and Cheltenham, four times 
a day, for four months, during which time it conveyed nearly 
3000 persons, and travelled 3564 miles ; it performed the dis- 
tance — 9 miles—in fifty-five minutes : the fare charged was 
one shilling. In consequence of the authorities placing heaps 
of stones on the roads, which caused the carriage to break 
down, and was attended with fatal results, he took his steam 
carriage off the road, after having run 315 journeys most suc- 
cessfully. 

In 1833 Sir Charles Dance came to London with his steam 
carriage, which, after having the boiler repaired at Maudslay's, 
attained the speed of 16 miles per hour. Mr. Alexander Gordon 
timed this experiment. In November, 1833, this engine and an 
omnibus were put on the Holyhead road. The engine had two 
cylinders 7 inches in diameter, with a 16-inch stroke ; a pres- 
sure of 100 lb. to the square inch was maintained in the boiler. 



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124 TRAMWAY ROLLING STOCK, 

The carriage, engine, and passengers weighed 6 tons, the rate 
of travelling averaged 7 miles an hour for 53 miles; the coke 
consumed was a little over a bushel per mile. 

In 1831 Messrs. Ogle and Summers built a steam carriage 
which attained a high rate of speed ; the greatest velocity they 
obtained over a rather wet road, with patches of gravel upon it, 
was between 32 and 35 miles per hour. It appears that their 
carriages went from the turnpike-gate at Southampton to the 
four miles stone on the London road, a continued elevation, at 
the rate of 24J miles an hour, loaded with passengers. They 
employed 250 lb. steam pressure to the square inch, and ran 
800 miles without accident. 

In 1833 Colonel Macerone went from London to Windsor and 
back in his steam carriage with eleven passengers; average 
speed 12 miles an hour. 

In 1834 Scott Russell established a line of steam coaches 
between Glasgow and Paisley as a regular mode of conveyance. 
An accident caused by the breakage of a wheel, and attended 
with fatal results, caused the Court of Session to interdict the 
whole set of carriages from running. Many other persons, 
among whom may be mentioned, Dr. Church, Messrs. Maudslay, 
Fraser, &c, tried their hands at steam carriages, but the 
oppressive tolls prevented their running except at a dead 
loss. 

At the time of the experiments of Gurney, Hancock, and 
others in England, several Americans attempted steam locomo- 
tion. The author is not able to give the exact dates of these 
early attempts, but about 1830 Mr. Harrison Dyer, of Boston, 
U.S., built a steam carriage, and about the same time Mr. 
Joseph Dixon, of Lynn, near Boston, U.S., built a steam car- 
riage, and many others tried their hands at solving the question 
of steam for common roads, among whom was a Mr. J. K. 
Fisher, who began experimenting about 1840, and continued to 
do so till 1859, building several carriages and making several 
trials. His cause of failure seems to have been the notion cir- 
culated by certain eminent English engineers that steam car- 
riages on common roads could never either run or pay. The 
author regrets that space will not allow him to explain the 
details of Mr. Fisher's invention, but thinks Mr. Fisher's 
carriages presented a -very sightly appearance, and that some of 
his details were very ingenious. 

In 1859 a steam carriage was tried on the Cincinnati tram- 
way; the constructor of the carriage was Mr. A. B. Latta, 
which was reported as having worked successfully, carrying at 
times as many as eighty persons. About the same time a 



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AND STEAM IN CONNECTION THEREWITH. 125 

steam car, constructed by Messrs. Grice and Long, of Philadel- 
phia, was in use on the tramways, with a pressure of steam 
equal to 50 lb. ; this car, besides making its journey in less 
time than with horses, could according to requirement draw an 
extra car. In 1860 there were five or six steam cars in use in 
the United States of peculiar construction, the engine and 
boiler being within the cars, and the whole being carried on 
two bogie trucks. Various other inventors came into the field, 
but without any practical results being manifested. Mr. 
George Francis Train obtained in 1860 a patent for an im- 

J roved steam carriage for street railways, which is shown in 
lg. 3. He claimed as new the idea of erecting engines on the 
platforms of an ordinary car, the fixing of the driving gear to 
the frame of the engine, and an excellent method of swivelling 
axle for use in guiding the carriage. 

In January, 1870, a company was formed in New Orleans for 
propelling cars by compressed air, each car to carry two tanks 
charged with air by steam, the cars to be fitted with crank 
engines, having laminated glued paper cylinders strengthened 
by cordage. One cylinder when finished was said to have stood 
a pressure equal to 300 lb. on the square inch. A car was 
experimented upon ; the cylinders were of iron, and weighing 
1600 lb., and leaky at the rivets ; starting with a pressure of 
90 lb. to the square inch, twenty-eight persons being on the 
car, 3£ miles was performed in 7£ minutes. In the same year 
a road steamer with rubber tires was tried in Paris with most 
satisfactory results. The tractive power was sufficient to draw 
a heavy omnibus containing fifty passengers ; the French Go- 
vernment granted these steamers permission to ply over two 
routes of several miles in length, and the Government en- 
gineers were of opinion that the engine was more handy, con- 
venient, and manageable than horses, and in no way a source of 
danger to the public The roads were rendered free from ruts, 
and the machinery from jolts, by the use of a huge indiarubber 
tire. The speed was as fast as that of an ordinary omnibus, and 
the engine ascended streets, namely, the Trocadero, of which 
the gradient was as much as 1 in 9, and descended without 
brake power. 

In the spring of 1870 a company was formed for introducing 
Thomson's road steamers in the city of Montreal, one of which 
had already been tried with perfect success in Edinburgh, 
having drawn an omnibus carrying sixty passengers through 
the streets of that city. The traction wheels were fitted with 
indiarubber tires ; the omnibus was also fitted with tires of the 
same material in addition to large bearing springs. The 



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126 TRAMWAY ROLLING STOCK, 

motion was so easy that it was impossible to tell when the 
machinery was pnt in motion. 

Mr. Anderson, superintendent of machinery, in his Report on 
the Thomson road locomotive, considered the indiarubber tire 
a complete success in introducing steam on common roads. In 
the trials made with this locomotive tires were used 12 inches 
by 5 inches, covered with a chain of steel plates, which came in 
contact with the ground. It traversed steep inclines, was run 
on to the sea-shore, carried heavy loads with the greatest ease, 
and that without frightening the horses. 

Later in the same year Mr. J. D. Lake invented a street 
locomotive, tried in Chicago, the improvement on ordinary loco- 
motives being that the power is first applied to a set of balanced 
wheels, whereby whilst stationary they may store up sufficient 
power for starting the engine with ease. Two sets of driving 
wheels were used — one for excursion, large; the other for 
small loads. 

In the same year — 1870 — it was proposed to use Emile 
Lamm's ammoniacal gas engine, which was used in connection 
with an ordinary street car. The engines were of piston and 
cylinder construction. The piston was propelled by the gas, 
whilst the exhaust was reabsorbed by a weak solution of aqua- 
ammonia ; and in 1871 a car was actually run in Orleans by 
this power. Either the cost or an after project of Emile 
Lamm's was the cause of its abandonment. 

In 1871 also Peter Salmon patented a steam tramway car- 
riage to be propelled by gps from oil used expansively, and in 
conjunction with steam raised from water by tne combustion of 
the oil gas. He also suggested the use of compressed gas 
received from depdts, the engine to be fireless. In 1871 Mr. 
Nairn employed a steam carriage similar in construction to a 
three-horse omnibus, but longer. It was driven by three 
cylinders. The funnel passed backwards under the seats for 
the outside passengers. The leading wheel was carried in a 
fork, and governed by a hand-wheel and worm. It carried fifty 
passengers, and weighed, when loaded, 10£ tons. It ran for 
hire from Edinburgh to Portobello for four months, a journey 
of 3 miles, twelve times a day. This carriage ceased run- 
ning rather suddenly, probably from the fact of the carriage 
having caught fire from the funnel which passed through it A 
patent was granted in 1871 to Leonard Jennett Todd for im- 
provements in steam tramway carriages, and three further 
patents were granted to him in 1873 and 1874. Mr. Todd, in 
describing his steamer, his "new pony/' fairly claims for it 
ample pulling and stopping powers, the capability of running 



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AND STEAM IN CONNECTION THEREWITH. 127 

in either direction, in turning the sharpest curves, working 
parts unseen, yet accessible, noiseless, smokeless, and steamless, 
and free from glare of fire by night, can be worked by a single 
attendant, efficiently steam braked, not complicated, and of 
sightly appearance. This engine runs on four coupled chilled 
wheels of 33 inches diameter, with a wheel base of 4 feet; out- 
side cylinder motion and valve gear of ordinary construction. 
The accumulator boiler has a large water space compared with 
the grate surface, so that increase of pressure cannot occur 
suddenly ; and the water capacity above the low-water level is 
sufficient for half an hour's consumption. The fire does not 
require attention while running, as it is very deep and charged 
with coke ; the driver has only to attend to water and fuel at 
the end of a journey. It is not absolutely necessary that the 
water be allowed to run down, as a pair of feed-pumps are con- 
nected with the engine and under the control of the driver. 
The " new pony " is double-ended, with duplicate driving plat- 
form and gear, a double-ended coke box to carry £ cwt. on one 
side; and a 100-gallon water tank on the other. 

In 1872 the Keminffton street car — Baxter's patent — was 
tried at Ilion, New York, on a road both crowded and difficult. 
The curves sharp, one curve less than 50 feet radius ; grades 
heavy, 1 in 13, with numerous points and curves. It has been 
made to run with a speed of 25 miles an hour. In the month 
of March, 1873, the City Railway Company thoroughly and 
satisfactorily tested the steam car built for them by Remington 
and Sons, Ilion, New York. The car made two round trips on 
Market Street, and was handled with great ease by the engineer. 
The car passed up and down Market Street with its scores of 
moving vehicles, and occasioned no alarm among horses or 
mules. The American Artizan of March 22nd, 1873, gives 
the following : " We recently witnessed a test of the Reming- 
ton steam car — Baxter's patent — on the Bloomfield road, near 
Newark, St. John's, which was pronounced by all present as 
exceedingly satisfactory. This car starts more quickly and 
stops more promptly than a horse car. It is faster, and passes 
the curves and points without the slightest hesitation, ana runs 
without noise or smoke. It ascended the steepest grade in the 
Bloomfield road, 7£ to 100, with, fifty-two passengers, and with- 
out using its reserve power, which is obtained by throwing high- 
pressure steam into the large or low-pressure cylinder of the 
compound engine. A car of this kind has been already sup- 
plied to each of the four different roads, and the reports from 
them are said to be most favourable. We understand that 
Remington and Sons have contracted to build 100 steam cars — 



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128 TRAMWAY ROLLING STOCK, 

Baxter's patent — for various lines. The coal consumption was 
1 ton per 1000 miles." 

In 1871 the late Mr. John Grantham took out a patent for 
improvements in steam carriages for tramways, and since that 
time has taken out several more. The carriage he employed 
was of the ordinary description worked by steam, and is seen at 
Fig. 4. He placed the machinery in a chamber on each side of 
the carriage in the centre of the compartment. Each chamber 
contained a boiler, water tank, and coal box ; the fires are fed 
by machinery. A double casing or air space may be madg 
round these chambers to prevent the radiation of heat into the 
carriage. The engineer stands on the front platform and works 
the engine, boiler, &c, by means of levers ; on reversing the 
car the engineer, disengaging the levers, takes them to the other 
end, and throws the machinery into gear, which enables him to 
work the engine as before. On one side of the car the wheels 
are without flanges to enable the car to travel curves. The 
boiler, when united by steam pipes, is attached to the box, which 
contains two safety valves. The cylinders are attached to the 
frame of the car, and worked with connecting rods, &c, in the 
usual manner. 

In October, 1871, James Go wans, of Edinburgh, had a 
patent granted to him for an improved traction car for drawing 
or propelling tramways. The invention consists in placing au 
engine and boiler inside a car specially constructed so that the 
working parts are hidden and carried upon wheels which run 
over tramway rails. The cylinders of the engine are inclined, 
their pistons are coupled to a crank shaft carrying a pinion at 
each end, which, when put into gear with toothed wheels, 
causes them to rotate. The exhaust steam is discharged 
through an air condenser through which a great quantity of 
air can be passed by means of a fan driven by the engine ; for 
guiding the car round the curves, or in taking points, a centre 
rail is used, on to which a guide rod attached to the car is 
lowered, in which case the front wheels of the car used need 
not be swivelled. The author cannot say if this car was ever 
tried, but thinks that the plan for guiding the car round points 
or curves could not answer, on account of the groove of the 
centre rail becoming filled up with dirt, and if the driver 
dropped the guide rod too soon, it would rattle over the stones 
and perhaps Break or damage the permanent way. 

In the same month Charles Randolph, of North Britain, had 
a patent granted to him for an invention for improvements in 
common road carriages. The body of the carriage is supported 
on two pairs of wheels, and of the same form as a stage coach, 



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ANt> STEAM IN CONNECTION THEBEWITH. 129 

is divided into three compartments, the centre one for pas- 
sengers, the forward one for steering meehanism and various 
controlling levers, the hind one for the boiler, engines, water 
tank, and coal bunkers. The boiler is of the vertical cylindrical 
class, with water tubes projecting down into an internal fire-box, 
with a central vertical uptake or chimney. The lower part of 
the boiler is tapered. The boiler is so arranged as to separate, 
and is connected with flanges. Mr. Bandolph employs two dis- 
tinct sets of engines, one on either side 01 the boiler. Both 
are connected with levers and handles to the forward compart- 
ment, so that the steersman has perfect control of each engine. 
Notwithstanding that both engines are connected with levers, 
they act independently of each other, so that the wheels may 
revolve at different speeds for whatsoever curve is being 
traversed. The exhaust steam is led by pipes into an annular 
chamber formed round the chimney ; from this chamber the 
steam enters the funnel in the form of an annular jet external 
to the smoke, so as to assist the draught without making much 
noise. The steam from the safety valves is treated in the same 
way. The draught is regulated by means of a damper arranged 
at the bottom of the ashpit, ana connected by parallel levers 
and links. 

Emile Lamm, the inventor of the fireless locomotive — seen 
at Fig. 5 — had his invention adopted by the New Orleans and 
Carroll Town Railway Company, with an advantage in favour of 
his system equal to 33 J per cent. The boiler, which has the usual 
fittings, is charged with water at 380° Fahr., and at a pressure 
of 170 lb. per square inch, from a stationary boiler. The engine 
is then ready to start, and a sufficient power is stored to enable 
the car to run a distance of 9 miles without expending the 
whole of it. At the end of the journey the water is again 
brought up to the necessary temperature by the injection of 
steam. Safety is apparent in this method, because the water 
from the beginning of the journey is continually decreasing in 
temperature and the steam in pressure. This system seems 
to find great favour in the United States and various other 
countries, as the parts are few and simple, with little or no 
danger to passengers. The one great disadvantage appears to 
be that the exhaust steam goes off in a damp vapoury cloud, as 
there is no special means of condensing it. On October 3 a 
trial of a fireless locomotive took place between East New York 
and Canartio. The dimensions of the engine are as follows: 
Boiler, 10 feet long by 46 inches diameter ; two cylinders 8 inches 
diameter by 12 inches stroke ; two pairs of wheels, 30 inches 
diameter, coupled ; ordinary slide valves, working without expan- 

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130 TRAMWAY ROLLING 6TOCK, 

sion, the engine being provided with double eccentrics and links 
for reversing. The exhaust is blown into two condensers, one 
for each engine. Its performances are as follows : It left New 
York at 2.52 p.m. with the steam gauge at 180 lb., and ran the 3& 
miles to Carroll Town — down grades — in 12 minutes and 45 
seconds ; at the end of the trip the gauge showed 108 lb., during 
the 9 minutes stoppage it fell to 104 lb., and the run back — up 
grades — in 17 minutes reduced it to 45 lb. ; no fire was used 
in the loromotive. It drew one car with 120 passengers. The 
net weight of the engine was 4 tons 3 cwt. The car itself was 
estimated to weigh 7J tons when empty, and with its load 12£ 
tons. In September, 1873, one of Lamm's tireless locomotives 
was tried at Chicago. The locomotive drew the car and was 
coupled in the usual way, managed by one engineer. The 
boiler was 8 feet by 3 feet, with the usual fittings. Steam 
supplied for a 6-mile trip from a depot. The supply boiler 
was 16 feet by 3 feet, steam pressure 200 lb. to the square inch. 
The locomotive was three parts full of cold water when the 
connection was made with the steam pipe of the stationary 
boiler before mentioned, when the steam rushed in the cold 
tireless boiler, and in a few minutes raised it to a pressure of 
about 180 lb. The connection was then uncoupled, and the 
tireless locomotive was ready for work. This engine drew a 
4-horse car 3 miles in ten minutes ; steam consumed 80 lb. ; 
locomotive started on its return journey with 90 lb. of steam 
remaining; when the starting point was reached there was 
57 lb. left ; the locomotive started on a return trip and con- 
sumed only 24 lb., it being a down grade ; but of course a hilly 
road vastly lessens the distance a car can run, for an incline of 
only 5 per cent, equals the rolling resistance of a street rail- 
way, and this doubles the total resistance. A grade of 1 per 
cent, consumes as much power in 3£ miles as do 10 miles of 
level line. Frequent stoppages also tell heavily against the 
limited power of the tireless locomotive, with which a consider- 
able deduction of pressure per minute must also be made for 
the loss by radiation, &c, from the time the receiver is charged 
with heat In the author's opinion, however, the principle of 
the fireless locomotive is a good one. 

In December, 1873, the Fireless Engine Company, of which 
Emile -Lamm was the managing director, obtained the per- 
mission of foe board of aldermen to run their locomotives on 
any of the city railroads above Fourteenth Street. This is a 
most important concession, and must be taken as an admission 
by the city authorities that the system can safely be worked 
without danger on our street railroads. 



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AND STEAM IN CONNECTION THEREWITH. 131 

The Sdewtific American gives the following account of a 
new fireless locomotive, built at the Grant Locomotive Works, 
and tried at Paterson, New Jersey, It had four wheels 36 inches 
diameter, and two cylinders 7 inches by 10 inches. The boiler 
was 37 inches in diameter and 9 feet 6 inches long ; the engine 
empty weighs 6 tons. On the trial with water heated to a tem- 
perature equivalent to a pressure of 150 lb. per square inch, the 
engine ran with an ordinary loaded horse car, a distance of 7 miles ; 
the track on which the trial was made is an ordinary horse-car 
track, laid on a common road with very heavy grades. The 
steam pressure after running the distance named, was reduced 
to 40 lb. to the square inch. 

In the same year the Scientific American notices a car 
invented by Mr. Robinson, shown at Fig. 6, which in the 
author's opinion is of very novel construction, and very inge- 
nious in the details. The boiler is enclosed in a fore compart- 
ment, and takes a bearing on a bogie truck of peculiar con- 
struction and supported on trunnions, so as to be capable of 
adapting itself to any grade. The horizontal cylinders are 
placed between the driving wheels, the piston rods are connected 
with the latter by means of slotted guide pieces. The driving 
wheels communicate, with the guide pieces by their crank pins, 
which are received and worked in the longitudinal slots. At 
the rear of the supporting frame the condenser is carried. The 
invention is in successful operation on Portland and Gorham 
roads, United States. 

A trial recently took place on the Manchester and Sheffield 
Railway between Grange Lane and Tinsley stations, of a tram- 
way engine, constructed by the Yorkshire Engine Company. 
It is built on Mr. L. Perkin's patent system, for the Belgium 
Street Railway Company, Brussels. The novel features of this 
engine consist in its not emitting any smoke or steam into the 
atmosphere, and making comparatively little noise. This engine 
used steam at 500 lb. pressure to the square inch, and main- 
tained this pressure by natural draught without any difficulty. 
The engine is compound, and expands the steam to the most 
economical limits, and then condenses it by means of two air 
surface condensers placed one on either side of the boiler. The 
engine can be driven from either end, all the driving gear 
being in duplicate, to obviate the necessity of turn-tables. The 
engine accomplished a speed of 15 miles an hour, drawing its 
full load up gradients varying from 1 in 200 to 1 in 80. The 
boiler has been tested up to 2800 lb. to the square inch. This 
engine has a single rubber driving wheel running on the stones 
between the rails ; this is also used as a steering wheel. 

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132 TRAMWAY ROLLING STOCK, 

The author last year designed the tramway locomotive shown 
in longitudinal section at Fig. 7, and in plan at Fig. 8. The 
engine and boiler are carried on two driving wheels 3 feet 
diameter, and four smaller wheels 2 feet diameter, the latter 
being attached to a bogie truck. The bogie is made so that 
one plate overlaps or rides on the other, with a chain attached 
to each corner of the upper plate which serves as a guiding 
apparatus for rounding points or curves. The framework of 
the locomotive is 7 feet long bjr 6 feet 6 inches wide. Instead 
of having one fire, as in most boilers, the author proposes to use 
two fires — one of coal and the other of coke. The air is forced 
by means of a fan into the lower or coal fire through the ashpit, 
which is closed and air-tight. The lower fire is enclosed in a 
dome with an opening at the top. The first dome has another 
dome or casing around it, and the exhaust steam and a volume 
of air are passed through this casing. The steam is thus super- 
heated and the air heated, the exhaust steam and air meet the 
unconsumed carbon from the lower fire, and mixing with it 
they pass together through the coke or top fire, where they are 
consumed or destroyed. The author believes that this boiler 
will ensure perfect combustion, great amount of heating surface, 
good circulation, and the thorough utilization of the waste 
steam. 

The engine is of the rotary class, and consists of a rotating 
cylinder having on its edge a semi-annular groove. At the 
centre of the cylinder is the driving shaft, the ends of which 
pass through discs, one on each side of the cylinder, the bear- 
ings being formed on the discs. Fig. 9 shows a vertical trans- 
verse section of the rotary engine. The pistons are carried by 
the cylinder and are withdrawn at the end of the stroke for the 
purpose of passing the fixed discs at the extremities of the 
cover ; the necessary intermittent motion is obtained by means 
of cams on the fixed discs. At the ends of the pistons are gud- 
geons, which carry friction rollers which work in the cams. 
The cover of the cylinder is also of the annular form ; at the 
extremities of this cover are discs which fit steam-tight into 
the groove of the rotating cylinder. The discs on each side of the 
cylinder have cut or raised on their inner surfaces continuous 
cams to receive the friction rollers. The main bearings are 
part of the side discs ; the brasses are made to taper, and are 
fitted with set screws, so that the cylinder is always central. 
The cylinder is keyed to the driving shaft, and is supported by 
the bearing in the side discs. The steam is admitted under 
the pistons at the extremity of the cover. The piston is thus 
moved forward the length of its stroke, whilst the action of the 



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AND STEAM IN CONNECTION THEREWITH. 133 

rollers in the cams brings the next piston into position. The 
exhaust steam passes out at the other end of the cover. The 
packing for the edge of the cover is a circular arc of steel, in 
section a triangle, which is placed in a groove of similar form. 
The packing is fitted with springs, and kept in position by set 
screws. 

The valve gearing consists of a cylinder formed in the steam 
pipe in such a manner that the cut-off of the steam may be 
regulated. The cylinder has cut through it at right angles to 
its axis a steam-way. This cylinder is made to revolve in a 
given ratio to the primary cylinder; keyed on to the main 
shaft are four pulleys, two on each side of the engine, one fixed 
and the other loose ; the power is transmitted from these pulleys 
to the driving shaft directly underneath the main shaft of the 
engine by belts, and thence by chains, to the axle of the driving 
wheels. The engine may be started, stopped, or reversed by 
the same lever. The locomotive when coming to the dead ends 
is reversed by means of a turn-table or side rail. But as the 
new Act of Parliament will not allow tramways to be made with 
dead ends, the question of reversing the engines is of secondary 
consideration. The driver has a brake which acts on the driv- 
ing wheels, and also on the wheels of the car. Instead of 
employing steam for the whistle, the author uses air, so that 
steam is not emitted from any part of the engine. Keyed 
on a shaft is a small fan, and on the same shaft a small 
turbine wheel, the whole occupying a space of about 6 inches 
square. The steam enters and propels the turbine, which 
communicates its motion to the fan, which in its turn sounds the 
whistle. 

The bogie truck consists of two principal parts, one carrying 
the leading and the other the trailing wheels ; the two parts are 
connected by a central pin, and are locked by folding plates, 
which turn freely on each other by means of friction rollers. 
The springs are; attached to the central pin ; to the frame of 
the bogie and near to the leading wheels the chains of the 
steering apparatus are attached, the apparatus consisting simply 
of a hand-wheel at the upper end of a vertical shaft, while at the 
lower end is a pulley round which the steering chain is passed, 
one link being fixed to the lower wheel by a stud. In front of 
the leading wheels, and attached by a swing joint and spring 
to the sill of the carriage, is a guard iron, the curved foot of 
which just clears the rail, and carries any obstruction before it 
until the engine is stopped. 

The subject of providing cars which are light, strong, and 
efficient, has been a source of considerable trouble to tramway 



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134 TRAMWAY ROLLING STOCK, 

companies. The car at present in use in London is constructed 
to carry forty-six passengers. It has a total length of 25 feet 
over the ladders ; of this 9 feet are occupied by the platforms 
and steps. This length is objectionable, as it involves a large 
amount of useless dead weight The brake also being applied 
from the end of the platforms tends to depress the ends of the 
car, so that the sill of the car has a considerable camber. The 
ladders are constantly a source of danger and expense, whilst 
on curves of short radius the overhang is considerable. The 
application of the brake power to one side of the wheel only 
adds much to the wear of the bearings and axles, and the 
release of the brake pawl is sometimes a source of danger 
to the driver. The weight of an empty car constructed to carry 
forty-six passengers is 2 tons 15 cwt., and that of a car carrying 
thirty passengers, 2 tons 4 cwt. The author has therefore 
designed an improved car, shown at Fig. 10, the chief features 
of which are the reduction in length and weight for the same 
number of passengers, and the rounded ends, whereby over- 
hanging is prevented and passenger accommodation improved. 
The central platform adds to tne stability of the roof and 
framing, and the staircase affords easy access to the roof. An 
elevated seat is adopted which gives the driver a greater range 
of rein and greater facility for handling the horses. The brake 
gear is arranged so that both sides of the wheels are gripped, 
thus equalizing the action and preventing undue strain on the 
adjacent parts. The author also uses an improved draw-bar, by 
means of which any sudden strain on the horses either at start- 
ing or stopping will be prevented. The weight of one of these 
cars built to carry fifty persons is 2 tons 6 cwt., and the length 
20 feet Those built to carry thirty-two passengers weigh 
1 ton 16 cwt., and have a length of 15 feet 6 inches. The 
weight is reduced in the first instance 9 cwt., and length over 
5 feet ; in the second instance, in weight 6 cwt, and in length 
4 feet 6 inches. 

It would seem from the many patents and the numerous 
experiments that have been conducted, that a suitable brake 
for tramway carriages has yet to be introduced. In 1873 
Mr. Lightbody patented a brake upon the wedge principle, the 
brake blocks being forced against the wheels by means of a 
wedge connected to the back of each brake block by a dove- 
tailed feather and groove, and fitted so as to slide freely, the 
wedge being connected so as to act together. By means of a 
screw, a lever placed under the carriage is eitner raised or 
lowered, and this has the effect of correspondingly raising or 
lowering the wedges. When the wedges are lowered, the 



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AND STEAM IN CONNECTION THEREWITH. 135 

brake blocks are forced against the wheels, and when raised 
the blocks are withdrawn. Another and more simple arrange- 
ment adopted by Mr. Lightfoot has a double lever ; one on 
either side of the carriage, worked by a screw, but acting 
directly on the rod which connects the wedges. This brake is 
being fitted to one of the Edinburgh tramway cars. 

The author has designed two forms of brake, in one of which 
the car is brought to a standstill by means of its own impetus, 
whilst in the other the power is that exerted by the driver. In 
the first brake — shown at Figs. 11 and 12 — the blocks are 
made to act on both sides of the wheel simultaneously. At- 
tached to the driver's seat, and working in a quadrant, is a 
lever so placed that the power applied by the driver is that 
gained by pressing his back against the seat and thrusting the 
lever forward with his hand. This acts through intervening 
levers upon a bell crank, one end of which is made to act by a 
rod upon one end of a small lever attached to the brake block- 
As that point is pulled forward, an equidistant point on the 
opposite side of the lever takes a backward motion ; this point 
and the other brake block are attached by a rod, thus ensuring 
the wheel being firmly and simultaneously gripped by the 
brake blocks. The quadrant is provided with a ratchet, whereby 
the power having once been applied may be continued at the 
pleasure and without further effort on the part of the driver. 
In the second form of brake the author employs a long lever — 
the fulcrum being at or about its centre — one end of 'which is 
acted upon by intervening levers worked by the foot or hand, 
the other end carrying in a forked bearing a loose pulley, two 
stout pins projecting from its side face ; a steel band or strap 
lined with wood — the ends of which are turned on the pins — 
passes round a fast pulley having two diameters on the driving 
axle. That part of the last pulley having the smaller diameter 
is embraced by the strap, the larger part being roughed, so that 
when the lever is raised the small loose pulley is brought down 
on to its curved surface and a winding or tightening of the strap 
commences, the result being the stoppage of the driving wheels. 
The loose pulley is provided with holes to allow of the pins 
being rearranged. 

Perhaps one of the greatest obstacles to the successful 
working ot the tramway system is the obstructive state of the 
grooves in which the wheels run. A great necessity exists for 
adopting means for obtaining a continually clear track. Several 
methods have been promulgated for obtaining this much- 
desired end, but with little success. In 1871 Mr. Hiram 
Saunders patented a track clearer, consisting of a plate of steel 



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136 TRAMWAY ROLLING STOCK, 

for use in winter, and a plate of steel combined with india- 
rubber, for use in wet weather. This was attached to the front 
of the car, and was pressed down on to the rail by springs. 
This was a complete failure ; it created so much friction that it 
was necessary to use four horses to the car to which the plough 
was attached. There was no apparatus for throwing the mud 
off the track, and the plough scraped the dirt out of the groove 
and laid it on each side of the rail and over the tread of the 
rail, and as the wheels followed it they had to run over the 
mud ; the friction was thus very great. 

In 1873 George Taylor Yull patented a track cleaner, which 
the author saw at work on the London tramways. Besides 
being very complicated, it would not plough the mud or 
stones out of the grooves, but passed over them, merely level- 
ling them. In the uame year George Bray patented a machine 
for the same purpose ; it was tried on the London tramways, but 
the author cannot say with what success. 

The author has this year patented a groove cleaner after 
some years of experiment. He made about twenty-two ma- 
chines before he gained any result. He had an apparatus 
which was self-acting, double-acting, and which cleaned the 
groove freely and with very little friction. All the machines 
were practically tried on a tramway car, and succeeded more or 
less. His last apparatus will clear out any material, and spread 
it from 10 inches to 15 inches from the track. One of these 
machines will clean from four to five miles of line, and keep it 
free for all the cars to pass over it. The saving effected will be 
very great, as it now costs tramway companies from 50Z. to 602. 
per mile per year for clearing the track. 

The first form of groove cleaner the author used consisted of ' 
an iron frame attached to the sill of the car by springs so as to 
allow for the fall and rise of the car. It carried on its fore part 
a steel plough breast free to swing in a direction parallel to the 
motion of the car. Impinging on the back of the plough breast 
was a spring for keeping the plough to its work, whilst any 
powerful resistance offered to it was avoided by the back 
motion of the spring. Attached to the same frame, and worked 
by a cross chain from the driving axles, was a brush of wire for 
the purpose of throwing out of the groove and off the track the 
joad matter left by the plough. 

In the second arrangement he employed a frame similar to 
the last, carrying on the fore portion a distance pulley running 
on the flat part of the rail, and working; a friction pulley carry- 
ing a disc, on the periphery of which were fixed steel tools, 
which were made to rotate in a direction contrary to that of the 



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AND STEAM IN CONNECTION THEREWITH. 137 

car. The speed of this wheel was so great that instead of 
throwing the mud on the breasts of the plough it threw it over 
itself on to the tread or into the groove again. The author 
then designed various other arrangements, which were more or 
less modifications of those already described ; but he was not 
more successful than with the others until his last arrange- 
ment had been worked out In this track clearer, which is 
shown at Fig. 13, the author attaches to the back of the axle- 
boxes an iron frame so as to connect the two, and bring the 
same into a form parallel to and over the groove of the rail. 
To the centre of the frame is attached a stud with back nuts. 
Fixed to this stud by a swing joint is a double plough with 
movable breasts ; the plough is kept in position by suitable 
springs attached to the frame ; this plough is thrown out of 
gear dv turning the point of the plough out of the groove. 
This plough, which answers very well, can be renewed by 
removing the bolt. 

In conclusion, the author would observe that it appears clear 
from the experiments of Murdoch, Trevithick, Hancock, Russell, 
Thomson, and others, that the greatest impediment to the 
introduction of steam for passenger carriages was formerly the 
bad state of the roads. They have, however, been in a great 
measure improved by the methods devised by McAdam and 
others. Tramway companies are suffering under the great evil 
of having to draw their cars by horses, and if an Act is not soon 
passed to relieve them in this respect, tramway companies will 
soon be things of the past. The introduction of steam on tram- 
ways will open up a field for engineers as wide as the railways 
did. It is generally admitted that street tramways could be 
worked far more efficiently and economically by steam than by 
horse power, as many millions are employed in Great Britain in 
constructing and working tramways, and some of the companies 
run as many as 200 cars daily, while new routes are constantly 
being organized* The law with respect to the use of steam 
upon common roads will, of course, need revising before steam 
can come into general use. What those alterations in the Act 
should be, may be inferred from the Report of the Select Com- 
mittee appointed to inquire into the use of Locomotive Engines 
on Public Roads. 

The author trusts that Great Britain will be the first to adopt 
universal steam traction on tramway lines, feeling sure that it 
will greatly tend to the prosperity of the country, and greatly 
benefit tramway companies. 



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138 TRAMWAY ROLLING STOCK, 



DISCUSSION. 



Mr. Thomas Mot said that he had been much interested in 
the paper, and might mention that he had designed and was 
engaged in making light engines, and he hoped soon to prove 
practically that steam could be used with safety and economy 
on tramways. He should like to direct the attention of those 
who were studying the subject of the application of steam to 
road traffic, to the question whether it would not be advisable 
to get rid of the tramway altogether, as he thought that tram- 
ways were in the way. Very good roadways were now being 
laid down in London both of wood and asphalte, and steam 
carriages could be guided about upon them as easily as boats 
on the water. Cars on tramways were often stopped by carts 
being upset on the track, and it was very hard work to get the 
cars off the track, to pull them along the common road, and 
then to get them on the track again at a point beyond the 
obstruction. It would be very damaging to the driving wheels 
of a steam tramway engine to treat the engine in that way. It 
was quite possible to have the cars propelled by steam without 
rails. He (Mr. Moy) and his partner were building several 
types of engines, some extremely light, some heavier, for sta- 
tionary purposes, and also marine engines. He believed that 
they would be able to furnish a very serviceable engine for 
tramway cars. But he certainly saw difficulties with tramways 
which had yet to be overcome, especially in shunting the engines 
from one line to another. He did not see his way clearly at 
present to the adaptation of steam to tramways. 

Mr. Ebnest Spon said that the names of Ogle and Simmers 
had been introduced into the paper, and the author had stated 
that their locomotives ran for a long time without any accident. 
He (Mr. Spon) happened to be personally acquainted with a 
millwright, named Thomas Don, who was manager of Ogle's 
factory when he was making the road locomotives, and Mr. 
Don had told him (Mr. Spon} that one of those locomotives met 
with a serious accident in tne Waterloo Bridge Road by run- 
ning into a shop window, and doing serious damage, and that 
it could not be controlled until the fire was out, and the 
engine stopped for want of steam. With respect to the allusion 
to Murdoch s experiments of 1787, he (Mr. Spon) believed that 
it had been proved two or three times that those experiments 
were mere tradition, and it was very much controverted whether 
Murdoch ever did run a locomotive or not ; and if he did run 
one it was only a model in some out-of-the-way country place. 
One thing that struck him during the reading of the paper 



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AND STEAM IN CONNECTION THEBEWITH. 139 

was the success which appeared to have attended all the expe- 
riments made in steam road locomotion ; and yet, in spite of all 
those successes, for some inscrutable reason, steam locomotion 
on common roads had failed to be generally adopted. There 
must be a reason for that, and the fact could not be ascribed to 
the perversity of municipal councils, for town authorities would 
be els pleased as anyone else to have good facilities for transit 
There must be some objection in the practice which had 
hitherto prevented its general adoption. Mr. Moy had raised 
one very great objection to the present system of tramways, 
which was the use of the rail. The common street car was con- 
tinually getting off the track, and it was a matter of very great 
trouble to get it on again. With a steam engine on tram rails, 
as Mr. Moy had pointed out, the difficulty would be much 
increased. Another objection was that there would be no means 
created of increasing adhesion in passing round curves. A 
third objection was that steam locomotion on the common roads 
would interfere with all the horse traffic in the streets, and 
certainly horse traffic would not be abolished without con- 
siderably more opposition than the trains worked by horses had 
experienced up to the present time. The author of the paper 
had omitted to mention one form of steam road locomotive 
which had several features in it more worthy of notice than 
many that had been brought before the meeting. It was a 
system in which the water in the boiler was heated by means of 
a powerful blowpipe, which was applied at each terminus. The 
boiler was surrounded by a very great thickness of non-con- 
ducting material, and retained sufficient heat in it to generate 
the steam required for one journey. When the blowpipe was 
applied to it again, the steam was got up in a very short time. 
He believed that the inventor was Mr. Henry P. Holt. The 
engine had four wheels, and there was an arrangement for 
increasing the adhesion upon the driving wheels, by throwing 
part of the weight of the car and passengers upon those wheels, 
when it was requisite to do so. 

Mr. V. Pendred said that Mr. Soon had very properly ob- 
served that there was some insuperable objection to the adoption 
of steam on common roads, or we should have had it long ago. 
He (Mr. Pendred) had had an extended experience of what 
steam was capable of, on common roads, with four or five dif- 
ferent systems of traction engines and steam omnibuses. The 
general result of his experience was that the reason why steam 
could not be used on common roads was the want of certainty 
in the action of any engine that had yet been produced. An 
engine might travel for a hundred or a hundred and fifty miles, 



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140 TRAMWAY ROLLING STOCK, 

and seem to be exactly what was wanted, and then break down 
in the middle of the night twenty miles away from every place. 
He supposed it was possible to produce an engine tbat was 
perfect. Such an engine must be, in the first place, exceed- 
ingly light, or it would burn 100 lb. of coal a mile, and when 
the disbursements were made for fuel and men, the owner 
would wish he had used horses to do the same work. On the 
other hand, it would be found, perhaps, that the. light engine 
would be wanting in adhesion. With an exceedingly light engine 
there would be no adhesion, and if there was adhesion enough 
to work, the result would be that the engine was too heavy to 
prove a practical success, so that there would be a break-down 
m some part of the scheme. The ideal of a thoroughly suc- 
cessful steam car for London would be a light engine, having 
cog-wheels working upon a set of racks, or a species of ladder- 
road. There would be then no difficulty about adhesion, and 
the light engine would work. Assuming a steam car to be run 
from the Bank to Charing Cross, it would, perhaps, pass 
through Cheapside very well, and then go down Ludgate Hill. 
It would then have to go up Fleet Street, and its proprietors 
would find that they had to measure the whole power of the 
car by what was required to go up any little bit of hill that they 
might come across. The engine must be powerful enough to 
get up the hill however short it was. There must be power 
enougn to overcome the worst bit of road on the route, no 
matter how short that bit might be. Of course, there might 
be level roads on which the car could be worked with ease ; 
but* so far as he knew, there had not yet been produced any 
engine which could be depended upon under all circumstances of 
weather. He believed that no one had gone so near success as 
Mr. Todd, and even in those engines which Mr. Todd had been 
working on the Santander road, great trouble had arisen from 
the increased resistance caused by the dust in dry weather, and 
the slipping of the wheels in wet weather. That difficulty had 
not yet been quite overcome. So far as he (Mr. Pendred) 
understood the paper, the author advocated the use of steam 
for tram cars ; but he did not seem to have overcome the dif- 
ficulties which had existed up to the present time in devising 
a suitable engine. 

The next point was the author's improved tram car, in which 
there were two or three objectionable features. First, there 
were rounded ends to prevent overhanging ; but overhanging 
could not be prevented in that way without sacrificing the 
power to carry two or three passengers. The middle platform 
would, no doubt, do the work of the two platforms ordinarily 



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AND STEAM IN CONNECTION THEREWITH. 141 

used, but he could not imagine anything much worse for use in 
London than a middle platform of that kind, with a ladder 
reaching to the upper part. Practically speaking, there was 
only one side for getting into the car. Then the opening at 
the top was calculated to cause accidents to passengers, who 
would fall down it at night. Possibly that objection might be 
removed. If the paper had contained a comparison between 
the existing London tramway systems and others, it would 
have been more instructive, fie did not know any place where 
the tramway system had been carried out so successfully as in 
Vienna, and some information with regard to its working there 
would have been very interesting. In that city passengers 
were never carried on the roof, but more cars were run to make 
up for the smaller number of passengers carried by each car. 
One of the principal advantages of that system was that the 
cars were able to go up inclines which in England were never 
ascended on a tramway. 

Another point, and one of the most vital importance as 
directly affecting the use of tramways, was the shape of the 
rail. It was impossible to say that we had arrived at anything 
like finality in that matter. No better example of that was 
afforded than the case of Liverpool, where the corporation had 
given the company notice to take up the rails, simply on 
account of the interference with the ordinary traffic, so that the 
rails would either have to be improved or removed from the 
roads. It appeared to him (Mr. Pendred) that before engineers 
discussed what was the best sort of carriage, or system of loco- 
motion, it was quite necessary to settle what rails the car could 
be permanently run upon. 

Mr. Mot asked Mr. Pendred whether he thought that a car 
weighing 2 tons 14 cwt, and having two wheels forced round, 
could possibly slip down Ludgate Bill, or refuse to ascend it, 
even supposing the engine weighed nothing* 

Mr. Pendred said that he considered that it was perfectly 
possible. The incline of Ludgate Hill was 1 in 32. He was 
assuming that they were running on asphalte. 

Mr. Mot asked whether that would be true when indiarubber 
tires were used. 

Mr. Pendred replied that indiarubber tires had proved very 
successful on the road, but totally unsuccessful as an economical 
speculation. 

Mr. T. Cargill said that he wished to offer a few remarks on 
the statement made by the author in the latter part of his 
paper, to the effect that if tram cars were worked by steam 
on the principle proposed, it would open a very large field to 



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142 TRAMWAY ROLLING STOCK, 

engineers. He (Mr. Cargill) did not think that was a state- 
ment which could be supported, as the subject of tramways was 
very much confined. Whether tramways were worked by 
horses or by steam, the very principle they involved occupied 
an intermediate stage. The traffic was neither railway traffic 
nor horse traffic in the ordinary sense ; and to compare tram- 
ways with railways as a field for engineers, was investing the 
question with an importance which certainly did not belong to 
it. The railway had to make a road for itself, while the tram- 
way worked upon a road already made. The cases in which a 
tramway had to make a road for itself were very rare. He 
certainly agreed with Mr. Spon, that horse labour would never 
be altogether superseded by steam, any more than manual 
labour would be dv machine work. No doubt many kinds of 
manual labour would yet be superseded by machinery, but there 
would always be some which would still be done by hand. 
Besides which, in future times, there might arise new crafts 
which would render manual labour necessary. He (Mr. 
Cargill) did not see that there was much to be done by en- 
gineers in promoting their interests by tramways, with the 
exception, perhaps, of the rail. The rails which were laid down 
in London — and which were, perhaps, as good as any others — 
caused immense discomfort, especially to the proprietors of 
private vehicles. It was true that for one person who owned a 
private carriage there were thousands who did not ; and of 
course the welfare of the public must be considered before the 
welfare of the individual. At the same time it was very an- 
noying to see the wheels of carriages wrenched off and the 
springs broken by the tram rails, as they sometimes were, espe- 
cially when the carriages crossed the rails obliquely. ' There 
was, therefore, very great room for improvement with respect 
to the raila Engineers had certainly not yet arrived at the 
best form. It seemed, therefore, premature to make improve- 
ments in the rolling stock until the best form of rail had been 
adopted. When the best form of rail had been devised, it 
would be time enough to direct attention to the superstructure, 
as the rolling stock might be called. 

Mr. Cargill here inquired whether Mr. Moy intended to use 
his steam engine on common roads with or without rails. 

Mr. Mot said he proposed to use it without rails. 

Mr. Cargill, continuing, said that as to the pavement of the 
road, he thought that they had arrived at the conclnsion that 
wooden pavement, as laid down in the Strand and some other 
parts of London, made the best sort of roadway for horse traffic. 
The roadway consisted of a concrete substratum, upon which 



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AND STEAM IN CONNECTION THEBEWITH. 143 

planks were laid obliquely, and wooden paving blocks, or sets, 
were laid on the top of the planks. Asphalte was not suited for 
roads, as it erred as much on one side as stones did on the 
other ; but it was well adapted for footpaths, and obviated the 
8loppiness which occurred in wet weather on the ordinary 
paths. 

Mr. Saundebs (who replied on behalf of Mr. Cramp) said 
that the objections which had been raised to the model arrange- 
ment of Mr. Cramp's car had been remedied, as 'shown in the 
drawing. The pillar of the staircase had been moved back 
close against the partition, and the staircase had been turned 
out and cut through. On the top of the car a hand-rail had 
been put round the opening to prevent passengers falling down. 
The seat had also been carried completely along the top, so 
that the whole of the space was utilized. As to the over- 
hanging of the car at curves, it would be found that that objec- 
tion was very greatly reduced in the car with the rounded ends, 
as compared with tne square-ended car ; and the rounded car 
was nevertheless made to carry the same number of passengers 
as the car in ordinary use. The model car showed a very large 
wheel base, but it would be found in the drawing that the 
wheel base was considerably reduced. 

Mr. Caboill asked whether the wheel base in Mr. Cramp's 
car was longer than that of the ordinary car. 

Mr. Saundebs replied that he believed it was very consider- 
ably longer. 

Mr. Caboill asked whether the car would turn as sharp a 
curve as that at i The Horns,' Kennington. 

Mr. Saundebs stated that he did not know the curve in 
question, but for any special case they would either shorten the 
wheel base, or have a revolving axle. 

The President said that the discussion had been an inter- 
esting one. Mr. Moy had called attention to the use of steam 
on roads without rails, and he (the President) believed that the 
day would come when tram rails on common roads would be 
considered barbarous, and that the engines and cars would, in 
time to come, be so improved that they would be capable of 
running on ordinary roads, as he thought they ought to do. 
Mr. Cramp appeared to. have an invention for cleaning the 
track ; but he had not stated whether its utility had been suffi- 
ciently tested by practice. It was probable that an efficient 
method might be devised for keeping the rails free from ob- 
struction. The presence of dust in dry weather and of mud in 
wet weather, were always difficulties in the way of effective 
working. The slippery state of the rails would be a drawback 



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144 TBAMWAT ROLLING STOCK, ETC. 

to the use of steam. With regard to the construction of the 
improved car, it appeared to him that the ladder would ob- 
struct the entrance of passengers. The position of the doorway 
in the centre of the car was a dangerous one, because passen- 
gers would get in and out while the car was moving, and would 
be liable to fall under the wheels. In the cars at present in use, 
the platform by which ingress and egress were obtained was 
at the rear, and if persons fell from it they fell clear of the 
wheels. The opening at the top appeared to be dangerous, as 
it did not seem to be sufficiently protected. 



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1 1 



PLATE 1. 




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PLATE 2 , 




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( 145 ) 



December 7th, 1874. 

JOHN HENRY ADAMS, Vice-Pbesident, in the Chair. 

THE FORMS AND CONSTRUCTION OF CHAN- 
NBLS FOR THE CONVEYANCE . OF 
SEWAGE. 

By John Phillips. 

The immediate and complete removal of fecal matter and - 
of liquid refuse of all kinds from houses and towns, so (hat 
neither the air, the ground, the wells, nor the streams shall be 
contaminated by these products, is a necessary condition of 
health. Three different systems of removal are in vogue, 
namely, the water-carriage system, the dry or pail-and-earth 
system, and the air or suction system. By the water-carriage 
system the fecal matter is immediately and completely 
removed in the drains and sewers which are necessarily pro- 
vided for conveying away the liquid refuse from houses, 
factories, streets, and other places ; while by the dry and air 
systems the fecal matter only is removed ; the former by the 
process of using pails and dried earth, and the latter by suck- 
ing the filth from the closets through pipes ; and the whole of 
the liquid refuse, which is as contaminating and deleterious as 
the fecal matter itself is carried off into the natural water- 
courses by a separate system of drains and sewers, the same as 
is provided for the water-carriage system. Experience proves 
that when the water-carriage system is properly planned, accu- 
rately executed, and well taken care of, it performs its func- 
tions most efficiently and most satisfactorily, and is much 
cheaper, both in construction and maintenance, than the other 
systems referred to. But when it is not so planned, so exe- 
cuted, and so taken care of, evils more or less injurious to 
health arise from the defects or the neglect. Hence where 
there is an obstruction, a deposit, a leakage, or a smell at any 
part, it may be taken as an axiom that either the form, the fall, 
the size, the construction, or the jointing of the drain or the 
sewer is at fault, or that some substance other than sewage 
matter, which the power of the water is incapable of raising 

L 

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146 THE FOBMS AND CONSTRUCTION OF CHANNELS 

and removing; has been washed or forced into it, or that some 
appliance necessary for its proper working is unprovided, 
wrongly placed, or out of order. 

- The water-carriage system consists of a series of drains and 
sewers which are kid to various depths and inclinations, for 
receiving and carrying away the water we use and the filth we 

Srodnce in our houses and towns. The efficacy of this system 
epends, as its name implies, upon the mechanical power of the 
water to remove not only itself, but the organic and inorganic 
matters which it receives. And as the water derives the neces- 
sary power to do this from the form, the fall, the size, and the 
evenness of the channels in which it runs, it is imperative that 
by no defect in these, in either of those respects, should any of 
this power be wasted or lost ; for the more power the water has, 
the better it raises and holds the matters in suspension, and 
propels them forward ; the quicker it carries them with it to 
the outfalls, the cleaner it keeps the drains and sewers ; the 
freer these are from noxious gases ; and the purer is the atmo- 
sphere, and the healthier are the inhabitants of houses and 
towns. At different periods various forms have been used for 
drains and sewers, such as the square, the rectangle, the tri- 
angle, the circle, the semicircle, the oval, the semi-oval, and 
parts of these combined. But the best form is that of an egg, 
broad at the large end and narrow at the small end, and this 
end placed downward. For by this form the channel imparts 
to the same quantity of water greater velocity and scour, the 
sides and crown offer greater resistance to the pressure of the 
ground, and the amount of excavation required to construct it 
is less than any other form. The egg-shape and the circle are 
now employed for large sewers, and the circle for small sewers 
and drains. As it is not generally known when and by whom 
the egg-shaped sewer of the proportions now universally in use 
was tir8t introduced, the author is enabled to supply the 
information. 

Thirty years ago, when the author joined the engineering 
staff at the Westminster Sewers Office, two large-sized sewers- 
one 5 feet 6 inches high by 3 feet wide, the other 5 feet high 
by 2 feet 6 inches wide in the clear — were in use for receiving 
the drainage of the houses and streets in that district. The 
form of these sewers was flat segment-bottomed, with upright 
sides and semicircular crown, as shown in Fig. 1. The manner 
of executing the work was also very indifferent, especially in 
the inverts, where the bricks were generally laid all headers 
without mortar or cement, a little grout only being poured over 
the surface after each length was completed. Up to the time the 
form represented in Fig. 1 was introduced, about eighty years 

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FOR THE CONVEYANCE OF SEWAGE. 147 

ago, sewers were built chiefly with flat-paved bottoms, upright 
sides, and arched crowns. Scores of miles of these sewer* are 
now in existence in the old parts of the metropolis, the bricks 
being soft and porous, the mortar weak and friable, the work- 
manship rough, and the inclinations extremely irregular. 
In 1846 there were about 150 miles of sewers in the West* 
minster district, 100 of which had slightly curved, and the 
remaining 50 flat bottoms, as the author has described. But it 
should be borne in mind that the object of sewers throughout 
the metropolis had always been, up to this time, to drain away 
the rainfall and subsoil water, and not to remove what is now 
called sewage, which consists of all kinds of used or soiled 
water and fecal matter. This had hitherto been thrown or 
deposited in permeable cesspools, through which the liquids 
percolated into the ground, and from which the solid matter 
was removed, by nightinen, when they were full. But in course 
of time, as the water supply and the consumption of water for 
domestic and trade purposes and for water-closets were increased,, 
overflow drains were permitted to be laid from the cesspools 
into the sewers. In tnis way the sewers came to be carriers of 
sewage as well as of rain and subsoil water. 

Owing to the extreme porosity of the bricks in these sewers, 
and especially to the immense number of open joints in the 
inverts, which amounted to about 60 feet lineal in each yard 
run of sewer, the greater part of the liquid sewage discharged 
into them constantly leaked through them, saturating the 
ground beneath, and leaving the solid sewage deposited upon 
their bottoms. During the author's examinations of the sewers 
he found in all, except th4 main lines, sewage deposit varying 
in depth from 2 inches to 3 feet.* This was evidently caused 
partly by the large width and flatness of the bottoms, which 
diffused the flow and destroyed its carrying power ; partly by 
their sieve-like character, which permitted the liquid to pei> 
colate through them as already mentioned ; and partly by the 
street detritus, which collected and formed dams chiefly oppo- 
site the mouths of the gully drains, and penned back the sewage 
matter. Hence the sewers consisted of a network of extended 
cesspools, which were emptied at intervals, when the accumula- 
tions stopped the house drains, by manual labour and cartage ; 
and the decomposing filth sent up constant streams of noxious 
gases into the atmosphere partly through the gully drains, J(ut 
chiefly through the house drains, the trapping of which was 
extremely defective, and no provision for conveying away the 
gaseous emanations by ventilating pipes or otherwise was then 

* See 'Pint Beport of Metropolitan Sanitary Commission, 1847/ pp. 42 
and 165. 

L 2 

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148 THE FORMS AND CONSTRUCTION OF CHANNELS 

thought of.* Here then was a state of things which induced 
and spread disease, raised the death-rates, and required to be 
remedied. After much observation and experience in the sewers, 
the remedy appeared to the author to consist in constructing 
the channels narrow, even, smooth, and water-tight, so as to 
concentrate the sewage, accelerate the flow, and prevent leak- 
age; and in providing the inlets with siphon-traps, so as to 
prevent the gases from passing through them ; and the outlets 
of the traps with ventilating pipes, so as to permit fresh air to 
enter and circulate through the drains and sewers, and the gases 
to escape above the levels of the houses. So far as the sewers 
put in under the author's superintendence were concerned, he 
took care that these should be smoothly, solidly, and tightly 
constructed, particularly in the inverts. This improvement, by 
largely preventing percolations through the bottoms, slightly 
increased the quantity and velocity of the sewage flowing along 
them. But their excessive width and flatness, as before referred 
to, spread the sewage so much that the flow was never strong 
enough, except where the body of sewage or the fall was large, 
to lilt and carry the sewage matter witn it What> therefore, 
appeared to the author necessary to ascertain was the form of 
channel that would give the sewage the utmost velocity and 
scour, and the rate of velocity at which it must travel to over- 
come the vis-inertise of the sewage matter, keep it in suspension, 
and carry it to the outfalls. 

In order to determine at what velocity the sewage must flow 
to keep the sewers free from deposit aim clean, the author, from 
1844 to 1846 inclusive, ascertained the velocities of the sewage 
currents in the Westminster sewers, both where there was 
deposit and where there was none [the result will be stated 
farther on] ; and in order to determine the form of channel that 
would give the same quantity of sewage the greatest velocity 
and scouring power, he made channels of various forms along 
the sewers, four of which, of equal width and equal area, are 
shown in Figs. 2, 3, 4, and 5 ; Fig. 2 being a semicircle, Fig. 3 
an elliptic-segment, Fig. 4 a parabola, and Fig. .5 a hyperbola; 
and for months he measured and computed the perimeters, 
areas, and velocities of the sewage flowing in them. It 
resulted from his experiments that when the same quantity of 
sewage was running in each channel, the velocity was greater 
at all depths, and the tendency to deposit mucn less in the 

* In the reign of Elizabeth, Sir Hugh Piatt, an ingenious lawyer, proposed the 
ventilation of "noisome drains and vaults," by a vertical pipe, of a convenient 
length, connected with the drain or vault. He said, " by this means offensive 
air, as fast as it is produced, will rise in the pipe, and be dissipated in the atmo- 
sphere."— See * Jewel House of Art and Nature,' p. 28, 1594. 

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FOB THE CONVEYANCE OF SEWAGE. 149 

elliptic-segment, Fig. 3, than in the semicircle, Fig. 2 ; in the 
parabola, Fig. 4, than in the elliptic-segment, Fig. 3 ; and in 
the hyperbola, Fig. 5, than in the parabola, Fig. 4. This was 
evidently due to successively contracting the bottoms of the 
channels, which successively increased the depths D of the 
streams, or the heights G of their centres of gravity ; and this, 
by increasing their gravitating energy and the slope of the 
surface, increased their velocity and scouring power. 

It is true that when each channel was running full, the wetted 
perimeter of Fig. 3« was slightly more than that of Fig. 2 ; of 
Fig. 4 than Fig. 3 ; and of Fig. 5 than Fig. 4 ; and for this reason, 
the velocity, according to the formula of Eytelwein, which is that 
usually employed for calculating the velocities of streams, should 
have been successively less instead of greater.* But owing to 
the increased velocity in each channel from increase of depth 
being in a greater ratio than the decreased velocity from 
increase of friction, the velocity was successively greater instead 
of less, as already stated. In other words, more velocity was 
gained by increasing the depth of the current than was lost by 
increasing the friction of the channel Hence there could be 
no doubt that an acute-angled channel with a sharp curved 
bottom, similar to Fig. 3, Fig. 4, or Fig. 5, was more suitable 
for the conveyance of sewage than an obtuse-angled channel 

* The formula referred to is as follows: V = 55 V2/-A, in which V = the 
mean velocity in feet per minute, / = the fall in feet per mile, and h = the 
hydraulic mean depth, which is obtained by dividing the cross section of the 
stream by its perimeter in contact with the channel. If we assume the semicircle, 
Fig. 2, and the parabola. Fig. 4, to be running full, and the fall of each to be 1 in 
264, or 20 feet per mile, by the formula the velocity of the flow in Fig. 2 will be 
173*91 feet ; and in Fig. 4, 167*75 feet per minute ; or 6*16 feet per minute less in 
the parabola than in the semicircle. Sow if careful experiments be made it will 
be found that the velocity will be more in the former, owing to the increased depth 
of the stream, than in the latter. As the result of the author's experiments 
with water and sewage flowing in open channels of various forms, he believes 
that the formula requires an expression for the whole depth of the stream, as well 
as for the fall and the hydraulic mean depth, in order to obtain the correct velocity. 
It is generally considered that the maximum velocity of a stream is at the middle 
of its surface. This cannot be, for the flow is retarded not only by friction against 
the sides and bottom of the channel, but by friction against the air at the surface, 
and this friction varies with the force and direction of the air. Hence the locus 
of the maximum velocity is at some central point below the surface, where the 
retardations from the surface, sides, and bottom are equal Humphreys and 
Abbott, in their * Report on the Physios and Hydraulics of the Mississippi River,' 
have proved that the velocity in a vertical plane is according to the curve of a 
parabola, whose ordinates represent the depths, and abscissa) the velocities at 
those depths, and that the axis of the parabola is parallel to the water surface, 
and identical with the locus of the maximum velocity, which is in the oentre of 
the stream at about Aths of its whole depth below the surface. Considering the 
great importance of this subject, in a sanitary point of view, mathematically con- 
ducted experiments and calculations of the flow of water and of sewage in various 
shaped channels should have been undertaken and determined long since by the 
Local Government Board, or some other authority, for hydraulic science in regard 
to sewerage is, even now, far from satisfactory. 



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150 THE FORMS AND CONSTRUCTION OP CHANNELS 

with a flat curved bottom, similar to Fig. 1 or Fig. 2. With 
regard to the sides, the author found that sharp convex side 
walls, with a large batter, similar to convex retaining walls, with 
a considerable slope, offered greater resistance to the lateral 
pressure of the ground acting against them, thau flat curved 
side walls with a small batter ; and with regard to the crown, 
he also found that a prolate-elliptic arch, while it sustained 
vertical pressure without distortion better than a semicircle, 

Save increased capacity and headway without adding but 
ightly to the cost. 

Combining these results, the author produced the egg-shaped 
sewer, shown in Fig. 6, which was adopted by the Westminster 
Commissioners of Sewers in place of Fig. 1. This was early in 
1846. The length of this sewer put down during that year and 
the following one was about 20 miles, and a saving of at least 
30,000/. was effected in materials and labour, and it turned out 
to be self-cleansing. It is known as the Westminster egg-shaped 
sewer. Its proportions are the following : 



CI = If AB. 
CE = AB. 

CF = UB. 
GH = I'AB. 



AJ = *AB. 

EK = UB. 

JL = fAB. 
KL = tVAB. 



In the latter part of 1847, or early in 1848, the author intro- 
duced the egg-shaped sewer shown in Fig. 7. The only differ- 
ence in this form and the last is in the crown, which is semi- 
circular, the invert being precisely the same and nearly ellip- 
tical, as represented in Fig. 3. The sewer shown in Fig. 7 
has been in use ever since by the Metropolitan Board of 
Works, the metropolitan district boards and vestries, the Local 
Government Board,* and wherever egg-shaped brick sewers 
have been put down in England, Scotland, Ireland, and Wales. 
It is also in use throughout Europe, India, North and South 
America, and the Colonies. The following are its proportions : 

CD=1*AB. I OP = iAB. 

OE = AB. J GH = i*AB. 

Details of this form, of various sizes, with solid invert blocks, 
are given in Plate I. of the ' Blue Book of Contracts,' which was 
written by the author, and published by the Metropolitan Com- 
missioners of Sewers in 1851. It is called the Metropolitan 
egg-shaped sewer. 

For some time before the egg-shaped sewer, Fig. 6, was 
adopted, a kind of egg-shaped sewer, as represented in Fig. 8, 

* See ' Suggestions as to Sewerage,' Ac., containing a sheet (Plate IV.) of the 
author's egg-shaped Bewer, Fig. 7, signed u Robert Rawlinson, O.E." 

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FOR THE CONVEYANCE OF SEWAGE. 151 

had been in use in the Holborn and Finsbury division. This 
sewer, which is drawn from the diagram and description of it 
given at pages 378 and 379 of the 'Sanitary Report, 1842/ 
has flat carved side walls with a slight batter, and a deep 
segment bottom, whose radius is little less than the radius of 
the crown. It was introduced by the late Mr. John Roe, in lieu 
of a sewer with a semicircular invert and crown joined by 
upright side walls, as shown in Fig. 9, which had long been in 
use in the Holborn and Finsbury, the City, the Tower Hamlets, 
and the Surrey and Kent districts. Fig. 8 has been very 
favourably compared for cleansing, for strength, and for 
economy, as against Fig. 1. But if Figs. 6 and 7 be compared 
for cleansing with Fig. 8, it will be seen that Figs. 6 and 7 are 
as superior in this respect to Fig. 8 as Fig. 8 is superior to 
Fig. 1 ; and as regards strength, Figs. 6 and 7 are much superior 
to Fig. 8. The invert of Fig. 8 is much too wide and too flat 
to be self-cleansing with the common flow of sewage. The 
sides are also too upright and the curvature too flat to resist 
great lateral pressure. This form of sewer has not been used, 
that the author is aware of, since 1847, Fig. 7 having entirely 
superseded it. It is known as the Holborn and Finsbury egg- 
shaped sewer. 

The daily production of sewage in towns varies with the con- 
sumption of water, namely, from 2 to 8 cubic feet per head of 
the population. When sewage channels are of proper form and 
size, and of even construction, the ordinary inclinations at which 
they are laid — from 1 in 200 to 1 in 600 — impart even to the 
smaller quantity of sewage the requisite velocity to keep them 
free from deposit. But the flow during the twenty-four hours 
of each day is extremely variable. From midnight till 6 a.m. 
or 7 a.m. it is at its minimum, but after this time it gradually 
increases, and reaches its maximum about noon or 1 p.m. Then, 
owing to the large sizes the sewers are obliged to be made for 
the purpose of accommodating the rainfall as well as the 
sewage, the maximum flow of the latter, during dry. weather, 
occupies only a small area of the inverts— not more in the mains 
than from one-sixth to one-third of their capacity — and owing to 
the velocity of the flow decreasing as the quantity of sewage 
decreases, the velocity is least, and therefore the sewage has 
the least carrying power during the minimum flow. Hence 
the channels shoula not be made semicircular, as is usually 
done, on the assumption that they are always running full of 
sewage, or of rainfall, or of both, but parabolic or hyperbolic, 
which forms are in accordance with the increment of the sewage 
flow, namely, extremely narrow and sharply curved at the 
bottoms so as to concentrate and give depth and force to the 

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152 THE FORMS AND CONSTRUCTION OF CHANNELS 

minimum flow, and gradually widening from thence upwards to 
the sides so as to accommodate the increasing quantity of 
sewage up to the maximum flow. 

This may be illustrated by reference to Figs. 2 and 5. In 
Fig. 2 the flat curved bottom E C F of the se ni circle, by spread- 
ing and depressing the minimum flow, decreases its velocity ; 
while in Fig. 5 the sharp curved bottom E F of the hyperbola, 
by concentrating and elevating the minimum flow, increases its 
velocity. Then as the quantity of sewage goes on increasing 
equally in both figures up to the maximum flow, owing to the 
width E F, Fie. 5, being much less than the width EF, Fig. 2, 
the depth of the flow goes on increasing in a much greater ratio 
in Fig. 5 than it does in Fig. 2, and, therefore, the greater 
depth D C, Fig. 5, over the depth D C, Fig. 2, is attended with 
this advantage, namely, it increases the gravitating energy and 
surface slope of the sewage, and this sensibly increases the 
velocity and scour. But it is during the minimum flow that the 
channel, shown in Fig. 5, acts with the greatest advantage, and 
whether it be 9 inches or 9 feet in diameter the advantage is 
proportionately the same. It is a question, therefore, whether 
the channels of main or outfall sewers should not be made in 
accordance with the increment of the sewage flow, that is, 
parabolic, as in Fig. 4, or hyperbolic, as in Fig. 5 ; for as outfall 
sewers have generally very flat inclinations, and as the bottoms 
when the circle is used have a broad and nearly flat surface, the 
minimum flow is scattered and depressed, the little velocity it 
has is still further weakened, and, therefore, deposit takes place 
along them. But making the channels of the form as repre- 
sented in Fig. 4 or Fig. 5, increases, firstly, the depth of the 
flow ; secondly, the slope of the surface ; and thirdly, the velocity 
and scour. And the effect of this is to maintain the sewage 
matter and the lighter silt in suspension, and to sweep away the 
"heavier substances and the detritus, which otherwise would 
collect and concrete along the bottoms, making them still wider, 
flatter, and extremely uneven, similar in fact to the rough 
bottoms of sluggish brooks. 

With a view to improving the egg-shaped sewer, Fig. 7, the 
invert of which has a form between the elliptic-segment, Fig. 3, 
and the parabola, Fig. 4, the author proposes to make it of the 
form as represented in Fig. 10, the bottom of which is nearly 
hyperbolic, as in Fig. 5. As by this improvement the channel 
would be narrower, and the curvature sharper than in Fig. 7, the 
velocity of the flow would be increased, and the sides would offer 
somewhat more resistance to the horizontal pressure of the 
ground. Where, however, the flow is large, as it is in the mains, 
the channel, as in Fig. 7, may still be used ; but where the flow 
is small, as it is in the branches, the improved channel, as in 

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FOB THE CONVEYANCE OF SEWAGE. 153 

Fig. 10, would be much more advantageous. The proportions 
of this sewer are as follows : The height G D is equal to 1 J the 
•width A B ; the radius G H is equal to 1£ the width A B ; the depth 
of the invert E G is equal to the width A B ; and the radius F G 
of the bottom is equal to £ of the width A B. 

Circular sewers of 18 inches, 21 inches, and 24 inches 
diameter are often constructed of brickwork, as represented in 
Fig. 11, because stoneware or fire-clay pipes of these sizes are 
more costly. It would be a great improvement to build such 
sewers of the shape shown in Fig. 11a, forming the inverts of 
solid terro-metallic or fire-clay blocks, solidly bedded on concrete, 
and turning half brick or concrete arches on the blocks, as shown 
in the diagram. As the channels exhibited in Figs. 10 and 11a 
are exactly alike, the blocks made for either would serve for 
both ; and if from points where Fig. 10 terminates and receives 
two or more 18-mch, 21-inch or 24-inch circular sewers, 
the form, as in Fig. 11a, were to be used instead, the uniformity 
of the hyperbolic channel would be maintained, and the velocity 
of the flow in each affluent increased. Where also large inter- 
cepting or main outfall sewers are required, the form shown in 
Fig. 11a would be as strong as, and more self-cleansing, than 
circular sewers. The following are the proportions of Fig. 
11a: Divide the width AB into eleven parts, then the depth 
E C of the invert is equal to 7£, the height CD is equal to 13, 
the radius F of the Dottom is equal to 2, and the radius G H 
of the sides is equal to 21| such parts. 

Sewers are now constructed of brickwork, of concrete, partly 
of brickwork and partly of concrete, and of earthenware pipes. 
In constructing 6ewers of brickwork or of concrete, it is of the 
greatest importance to build them accurately to the inclinations, 
perfectly to the curvature of the sections, thoroughly sound, 
solid, and water-tight, and perfectly smooth, even, and regular. 
By particularly attending to these essential points, distortion 
and leakage are prevented, and the flow of the sewage is 
accelerated. Bricks for sewers should be sound, solid, hard 
burnt, as non-absorbent as possible, and well wetted before they 
are laid. Where the curvature is under 15 inches radius, it is 
desirable to use radiating bricks. As the chemical action of 
sewage and of sewage gases renders most kinds of cement and 
mortar friable and rotten, Portland cement only, which is nearly 
proof against such action, should be used in the construction of 
sewers whether of brickwork or of concrete. The proportions 
should be one measure of sharp sand, one of fine, and three of 
coarse gravel, and one of best-tested Portland cement. The 
ingredients should be well turned over on a platform before 
wetting them, and then thoroughly mixed with clean water. 
Concrete thus compounded, and carefully compacted in the work, 

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154 THE FORMS AND OONfiXBUOTIOV OF CHANNELS 

is jointless, and non-absorbent of moisture and of gases, and 
stronger and more durable than brickwork for sewers. Whether 
the sewers are built of brickwork or of concrete, the bottoms, as 
high as the sewage usually runs, should be formed of three 
courses of solid terro-metallic or fire-clay blocks, in lengths of 
1 ft, 6 in. or 2 feet, as shown in Figs. 10 and 11a. They should be 
accurately moulded to the curvature, grooved and combed at the 
joints, highly vitrified and glazed, solidly bedded on brickwork, 
concrete, or hard solid ground, and tightly jointed against 
leakage with cement. 

Since 1851 hollow blocks have been used as keystones in the 
inverts of sewers ; how or by whom they were introduced the 
author is not aware. When it is considered that the weight of 
the sewers and of the ground pressing upon and against them is 
carried by the side walls down to these blocks, as shown in 
Fig. 12, it will be obvious that this practice is a great mistake. 
Where the weight is excessive, as it is in clayey ground, and at 
great depths, hollow blocks crack and break in pieces. Owing 
also to their thinness, and to the want of support at the ends for 
the cement, the joints cannot be securely stopped, and in con* 
sequence the sewage escapes through them, softening and 
saturating the surrounding soil, and the voids in the blocks 
become filled with sewage matter. It is true that where the 
subsoil is wet the voids permit the water to drain through them 
during the building of the sewer ; but where the ground is sandy 
as well as wet, the water carries the sand with it through the 
joints into the sewers, causing them to subside, and the channels 
to fill with sand, unless the flow is strong enough to carry it 
away. A much better plan would be to lay a pipe drain under 
the invert, and fill in the sides and cover the top with concrete, 
so as to form a solid foundation for the sewer. Sometimes the 
voids in the blocks are filled with concrete before the blocks are 
laid ; but even this does not prevent them from being shivered 
when the weight is excessive. On the whole, using hollow blocks 
at all in sewers, especially as keystones in the inverts, is bad con- 
struction, and therefore solid blocks, made as already described 
and as shown in Figs. 10 and 11a, should be used instead. Solid 
blocks could be made and burnt as easily as hollow blocks, and 
would be truer in shape, much stronger, more durable, and 
cheaper. 

However perfect the form and finish of channels for carrying 
sewage may be, they are rendered nugatory in these respects if 
they contain deposit. What, therefore, the engineer has to 
guard against in arranging and constructing sewage channels is 
to prevent deposit from taking place within them. To accomplish 
this he should always bear in mind that heavy sedimentary 

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FOR THE CONVEYANCE OP SEWAGE. 155 

matters have to be transported ; that the liquid sewage is the 
transporting power, and that this must move with sufficient 
velocity to raise and keep the sediment in suspension and con- 
vey it to the outfalls, He should further bear in mind that the 
velocity of the flow is not only always much greater along the 
middle than it is at the sides of the channel, but that it is con- 
siderably increased and made more powerful along this part by 
contracting the channel and thus increasing the depth or 
raising the centre of gravity of the stream. The quick central 
current thus produced draws the detrital and sewage matters 
into it from the sides, raises and holds them in suspension, 
and sweeps them .forward. Where from inadequate inclina- 
tion or body of sewage the velocity of the flow is insufficient 
to carry away the silt, sand, and other solid substances which 
are washed into sewers from sculleries, areas, yards, streets, and 
other places, these materials become embedded in and entangled 
with the excreta, fat, hair, paper, and other matters, and form 
hard cemented masses along the bottoms of the sewers. Wide, 
flat, and extremely rough surfaces are thus produced, which 
diffuse the flow, weaken its force, and no flush of water is 
strong enough to tear up and remove the accumulations. Hence 
it is of the first importance to keep detrital substances out of 
the sewers as much as possible. This may be done by forming 
catch-pits under the sinks and gullies, and emptying them 
directly after every rainfall. Where no such appliances are 
provided, or the emptying of them is neglected where they are 
provided, detritus is carried into the sewers, causing putrefying 
matters to deposit and foul gases to generate, and from thence 
the gases escape into the houses and streets where the drains 
are not properly trapped and ventilated. It was owing to 
observing the mischief which the street detritus produced in 
the sewers that the author was induced to invent and introduce, 
in 1848, siphon-trapped catch-pits, and hinged gratings with 
narrow spaces between the bars, for the gullies in the metro- 
polis. The detritus thus caught in the pits was easily removed 
therefrom, and thus the sewage was relieved from this obstruc- 
tion to its flow. Details of these gullies are shown in Plates 
VII. to XIV. in the ' Blue Book of Contracts ' before mentioned. 
Similar catch-pit gullies have been generally used in the 
metropolis and other towns ever since. 

The experiments of Dubuat relating to the removal of 
detrital substances of various sizes and weights by streams 
flowing with different velocities, as detailed by Professor 
Kobison, in the article " Biver," in the ' Encyclopedia Britan- 
nica,' have often been quoted in reference to the removal of 
sewage. In 1844 the author repeated these experiments with 

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156 THE FORMS AND CONSTRUCTION OF CHANNELS 

the sewage running in the Westminster sewers, in order to 
ascertain the velocities of currents necessary to remove the silt, 
sand, gravel, pieces of stone and brick, and other materials, the 
sewers then contained, and were continually receiving from the 
surface of roads, streets, and houses. But he found that as the 
sewage was charged to its maximum capacity with comminuted 
organic and inorganic matters of a highly clammy character, a par- 
ticular velocity was necessary to prevent deposit^ which the ex- 
periments as to the removal of detrital substances were incapable 
of determining. He therefore determined to deduce, if possible, 
from the flow of the sewage itself the rate of velocity at which 
it must travel to hold the sediment in suspension, and carry it 
without the detrital matters to the outfalls. With this view, 
from 1844 to 1846 inclusive, as before stated, he measured and 
computed the velocities of the sewage flowing in the sewers. 
He observed that where there was a large flow and a small 
inclination, the former compensated for the deficiency of the 
latter ; and where there was a small flow and a large inclination, 
the latter compensated for the deficiency of the former in pro- 
ducing the requisite velocity to keep the sewers clear of deposit; 
and it resulted from his experiments that where there was no 
deposit the velocity of the flow was more, and where there was 
deposit the velocity of the flow was less, than 2| feet per 
second, or If mile per hour ; and that whether the flow or the 
inclination was large or small, so long as the body of sewage 
travelled at this rate of velocity the sedimentary matters were 
completely carried away. 

This result threw a new light on the science of sewerage ; 
for we have only to make the channels of the form as exhibited 
in Fig. 3 or 1 ig. 4, where the body of sewage is large, or as 
shown in Fig. 5, where it is small, and give them inclinations 
that will cause the velocity of the flow to be not less than 2& 
feet per second, and they will be perfectly self-cleansing. This 
principle was first enunciated by the author in his evidence 
before the Metropolitan Sanitary Commission in 1847.* Sub- 
sequently, Beardmore quoted it in his work.on i Hydraulics,' t and 
Bazalgette adopted it (with a modification, certainly not for the 
better) in arranging the inclinations of the sewers for the main 
drainage of the metropolis ; % and engineers generally have 
ever since regulated the inclinations of sewers in accordance 
with it. In Mr. Baldwin Latham's excellent work on ' Sanitary 
Engineering,' there are a series of tables calculated upon this 

* See « First Report, 1847/ pp. 177, 188. 
t See first edition, 1850, p. xii. 

t See Paper " On the Metropolitan SyBtem of Drainage," vol. xxiv, 1864-65, of 
' Minutes of Proceedings of the Institution of Civil Engineers.' 

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FOR THE CONVEYANCE OP SEWAGE. 157 

principle. By reference to them the engineer can tell at a 
glance what fall to give his sewers, with various depths of 
sewage running in them, in order to produce sufficient velocity to 
keep the sewage matters in suspension or prevent them from 
depositing. 

The operation of flushing consists in placing movable dams 
or hinged gates at intervals across the sewers, so as to head up 
the sewage, and then, by suddenly lifting the dams or opening 
the gates, sweeping away the deposits by the downward rush of 
the sewage. However valuable this expedient may be, the prin- 
ciple of contracting the channels and regulating the inclinations, 
so as to give the sewage a velocity of 2 J feet -per second, is far 
more so. Where the body of sewage or the inclination or form 
of the channel is such as to produce this rate of velocity, 
there is no need to provide for flushing ; but where the body 
of sewage or the inclination or form is insufficient to generate 
the required velocity, the sewage matters will deposit and accu- 
mulate, unless provision is made to flush them away. The 
flushing system was actively employed in the Surrey and Kent 
district, from 1810, on the line of the Great Duffield Sewer and 
its branches from the Archbishop's Palace, at Lambeth, to its 
mouth near Salisbury Stairs, at Bermondsey.* About 1840 
it was introduced, with special apparatus to work it, in the 
Holborn and Finsbury division, by Mr. John Roe. The improve- 
ments of Mr. Roe in regard to discharging sewage were directed 
not so much to producing a channel that would be self-cleansing 
with the common run of sewage (this will be evident by refer- 
ing to the broad bottom of the Holborn and Finsbury egg-shaped 
sewer, Fig. 8), but to (t removing the animal and vegetable 
matters and the street detritus, by one comprehensive system 
of flushing," Dubuat's experiments, already mentioned, being 
the guiding principle of the system.f So much was flushing 
thought of and advocated for some years as the only proper 
method to be adopted to carry away the street detritus through 
the sewers, and to keep the sewers themselves free from deposit,} 
that hundreds of expensive flushing apparatus were fixed in 
them, where, if deep narrow channels, similar to that exhibited 
in Fig. 13, had been laid down along the inverts instead, as the 
author strongly advised should be done in 1847 and 1848, the 
velocity of the ordinary sewage flow would have kept such 
channels perfectly clean without the aid of flushing. 

From the subterranean survey which was made of the sewers 

* Bee Reports of Surveyors to the Commissioners of Sewers for the Surrey and 
Kent District, 1843. 
f See • First Report of Health of Towns Commission, 1844,' vol. ii., pp. 160-163. 
X See 'Sanitary Report, 1842/ pp. 54, 58, 376, and 390. 

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158 THE FORMS AND CONSTRUCTION 09 CHANNELS 

of the metropolis a quarter of a century ago, the greater part 
of them were discovered to be sewers of deposit. Sufficient 
information as to their forms and levels was then obtained for 
laying down a general plan for making almost all of them self- 
cleansing with the common flow of sewage. But the system of 
flushing was generally adopted by the Metropolitan Commis- 
sioners of Sewers instead, and this system has been followed 
ever since. At the present time there are about 600 miles of 
sewers in the metropolis whose channels are so broad, uneven, 
and undulating, that thejr require to be regularly flushed to 
prevent them from choking up with the excreta and other 
matters which are discharged into them. It is a popular 
fallacy among the uninitiated that the main drainage executed 
by the Metropolitan Board of Works has effectually improved 
the whole of these sewers. On the contrary, all that the main 
drainage has dime, and is capable of doing, is to intercept the 
sewage from the Thames opposite London, and pour it into the 
Thames again some miles lower down, between Woolwich and 
Erith. The channels of no part of the 600 miles of sewers of 
deposit which communicate with the main drainage system 
have in any way been improved by it. Hence they spread the 
sewage, weaken its flow, and accumulate deposit, just the same 
now as they did before the main drainage works were begun, 
and they will continue to do so until deep narrow channels, 
proportionate in size to the quantity of sewage running in them, 
are laid down along the inverts, as represented in Fig. 13. If 
this essentially necessary work were to be carried out where 
deposit sewers are situated, the sanitary condition of the 
localities would be greatly improved by it. The author pro- 
posed this plan to the Metropolitan Sanitary Commission in 
1847,* and also to the Metropolitan Commissioners of Sewers 
in 1848, but without effect Since then it has been adopted in 
a few sewers which had accumulated deposit, and been flushed 
at intervals, for more than twenty years, and it has answered 
admirably. The maximum sewage flow every day acts as 
a flush, and keeps the new channels perfectly clean ; and thus 
the cost of sending men into the sewers to flush them has been 
saved. Moreover, there being now no deposit of putrescent 
matter in the sewers, the houses and streets are free from 
noxious gases, which they had never been free from before. 

The total amount expended in flushing the 600 miles of 
deposit sewers in the metropolis during the last quarter of a 
century has been about 330,000?. This is at the rate of 1 3,200?., 
or one penny per foot lineal, per aunum. This expenditure, 
which the ratepayers must provide for in order to prevent the 
• See * First Beport, 1847,' p. 178. 

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FOR THE CONVEYANCE OP SEWAGE. 159 

sewers from choking up, is the result of the original defect in 
the form of the channels, which, by destroying the carrying 
power of the sewage, promotes the deposition of the putrescent 
matters which it contains. The average cost of laying down 
self-cleansing channels along the sewers, as exhibited in Fig. 13, 
mould be about 3*. 9±d. per toot lineal, or 1000Z. per mile. Con- 
sequently the total cost of the 600 miles would be 600,000?. 
The 13,z00Z., or the penny per foot lineal, per annum now ex- 
pended for flushing these sewers, would pay off the principal 
and interest in thirty years of the 600,0001 required to make 
them self-cleansing. Or as the coal tax is usually appropriated 
to metropolitan improvements, and this work is essentially of 
that character, the money required to execute it could be easily 
raised from this source. 

Glazed stoneware and fire-clay pipes have been and are 
largely used for sewers and drains. Such pipes are generally 
made circular, as represented in Fig. 14. But the form shown 
in Fig. 15, which has a hyperbolic channel and a semicircular 
crown, would be a great improvement. In Fig. 15 the mini- 
mum flow E C F would have less frictional surface, more depth, 
and consequently greater velocity than the minimum flow EOF, 
in Fig. 14. The velocity at all depths up to the maximum 
flow would also be greater in Fig. 15 than in Fig. 14. If, 
therefore, the form which generates the utmost velocity is to 
decide which channel is best for the conveyance of sewage, 
then unquestionably Fig. 15 is far superior to Fig. 14, and 
should be adopted in place of it. But it has been urged, as an 
objection to employing pipes of any other shape than circular 
for this purpose, that owing to the distortion which takes place 
during the drying and burning of the clav, they cannot, while 
being laid, be made to fit each other so well at the joints as the 
circular pipes, which can be turned round until the convex dis- 
tortion in one pipe fits the corresponding concave distortion in 
the other. Btence, truth of form, evenness of surface, and 
increase of velocity, which are essential in order that the water- 
carriage system may work with efficiency, are sacrificed, because 
of the distortion which is unavoidable in the manufacture of 
these pipes. 

But this is not all. Owing to the irregular shape of the 
sockets, and to their internal diameter being much larger than 
the external diameter of the spigots, when the pipes are put 
together they never fit each other at the joints so as to produce 
concentricity, but breaks or protrusions are formed round their 
interior, which may be seen by laying a few pipes together upon 
a board or plank. Moreover, owing to the difficulty of getting 
at the under side of the joints after the pipes are laid, the joints 

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160 THE FORMS AND CONSTRUCTION OF CHANNELS 

at this part cannot be cemented so as to be made perfectly water 
and air tight without great care and supervision. Also, owing- 
to the gaping openings at the sides and top of the joints, which 
are caused by the space in the sockets being much larger than 
the spigots, the cement used in stopping them squeezes through, 
drops on the bottom, or forms frills round the interior of the 
joints. Sometimes the droppings and frills are removed by a 
wiper or scraper as the pipes arc laid, but more often they are 
not Another drawback to the production of true, even, and 
regular channels for the conveyance of sewage by earthenware 
pipes is their short length of 2 feet. If engineers were to 
specify them 3 feet or even 4 feet, they could easily be made of 
tnese lengths. The advantages would be that the number of 
joints, or rather points of leakage, would be reduced one-third 
by the 8-feet pipes, and one-half by the 4-feet pipes ; and that 
the velocity of the sewage would be unchecked and greatly 
increased. The pipes when half dry should be submitted to an 
extreme pressure oetween polished iron moulds of the exact 
shape the pipes are intended to be. This would not only 
greatly increase their density and impermeability, but render 
them perfectly straight and true of form, which qualities they 
would afterwards retain in drying and burning. 

From the defects in earthenware pipes as now made, it 
results (1) that the velocity and discharge of the sewage in 
the semicircular channels, from the minimum to the maximum 
flow, is not nearly so much as it is in parabolic or hyperbolic 
channels ; (2) that the flow of the sewage is greatly impeded, 
and the bore of the drain or sewer is much reduced, by the dis- 
torted shapes of the pipes, and the breaks or protrusions at the 
joints; (3) that 6olid and other substances are caught and 
arrested Dy the obstructions, which sometimes cause the matters 
to accumulate until they choke up the drain or sewer ; (4) that 
the sewage constantly leaks through the joints, especially at 
the under part, diminishing its quantity and carrying power, 
and producing deposit, permeating and softening the subsoil, 
and causing the pipes to sink and no longer act as drains, and 
poisoning the wells ; and (5) that water and sand in the sub-' 
soil pass through the joints into the pipes, filling the channels 
and very often stopping the drains or -sewers. 

With a view to remedy these defects, the author has recently 
invented a new joint, which can be easily made perfectly tight 
against leakage, and will ensure concentricity of the pipes, and 
of their being solidly laid. Fig. 16 is a longitudinal section, 
and Fig. 17 a top-elevation of the joint. S is a spigot made 
slightly tapering, with a like tapering collar s of larger diameter, 
and gg are two small annular grooves, one being near the 

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FOR THE CONVEYANCE OP SEWAGE. 161 

)int of the spigot and tbe other in the centre of the collar. 

is a socket also made slightly tapering, with a like tapering 
let/. Round the spigot a rim is formed of the same diameter 
i the socket, its object being to support the spigot end of the 
ipe when laid on the ground. Before the pipes are laid two 
astic rings of caoutchouc and hemp, specially made for the 
urpose, are slipped into the grooves g g, the spigots are then 
laced into the sockets and forced home. As the rings com- 
letely fill and adapt themselves to the vacant spaces round the 
3llar 8 and the fillet /, the pipes are rendered concentric, and 
tie leakage of the' cement used in stopping the joints into or 
ut of the pipes is prevented. Between the spigot and socket, 
nd the collar and fillet, an annular cavity e is formed, which is 
ompletelv filled with liquid cement or asphalte, which is poured 
a through the aperture a made in the periphery of the socket 
oints formed in this manner will be perfectly water-tight, and 
•wing to their tapering shape the pipes can be readily taken 
part, and the annular filling in removed without injuring them, 
o that they can be again in like manner jointed together or to 
►ther pipes. This invention, the author has no doubt, will 
accomplish what has been so long desired to make earthenware 
>ipes concentric and water-tight. 

The author, however, is of opinion that pipes for sewers and 
lrains could be manufactured of Portland cement, perfectly 
mpermeable, accurately fitting in the joints, true of shape, con- 
siderably longer and consequently with fewer joints, much 
stronger and more durable than earthenware pipes; for 
Portland cement possesses the valuable property of setting and 
becoming intensely hard as well in water as in air, ana the 
hardness goes on increasing indefinitely. It also has the pro- 
perty of resisting compressive and tensile strains much more 
than vitrified stoneware or fire-clay, and of retaining the 
exact form impressed upon it while setting and hardening, 
which is unobtainable in earthenware. Moreover, it is almost 
proof against the chemical action of sewage, the effect of 
which is to destroy most cements and lime mortars. Hence, 
Portland cement is eminently adapted for the manufacture 
of pipes tor the conveyance of sewage. On the Continent, 
especially in Germany and Austria, such pipes are largely 
employed for this purpose, and most excellent pipes they are. 

The process to be observed to produce pipes in this material 
should be as follows: The cement, with the addition of a 
small quantity of chemical fluid to give it cohesion, should be 
well mixed by a machine to bring it to the consistency of a 
plastic paste — similar to glazier's putty. In this state it should 
be put into strong polished iron moulds, and therein subjected 

M 

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J 62 THE FORMS AND CONSTRUCTION OF CHANNELS 

to great compression by a machine so as to render it as dense 
as possible. By thus mixing and condensing the cement the 
pipes may be removed from the moulds soon after they are 
made ; and in two or three days they would be as hard as stone, 
have when struck a clear metallic ring, and be fit for use. As 
by this method of manufacture all the pipes and all the sockets 
and spigots would be precisely alike in form and dimension, the 
spigots would truly fit into the sockets, and the pipes when laid 
would appear inside as one continuous pipe, without the slightest 
uneyenness or irregularity at any pad;, or break or protrusion 
at any joint. In jointing the pipes the spigots would be smeared 
with liquid cement, and then pushed home into the sockets. 
Liquid cement would then be poured into the opening in the 
sockets, so as to completely fill the annular cavity within the 
joints. With pipes thus made, laid in straight lines to regular 
inclinations, and tightly jointed as described, we should obtain 
sewers and drains perfectly straight* uniform of section, even of 
surface, and tight at the joints, which are the desiderata for 
channels for the conveyance of sewage. 

DISCUSSION. 

Mr. Lewis H. Isaacs said that Mr. Phillips had contributed 
a very instructive and interesting paper, in which he had given 
in a succinct form the history of the sewage channels of the 
metropolis. The deductions he had drawn from experiments 
and practice especially having reference to Figs. 2, 3, 4, and 5, 
were highly instructive and very useful. He (Mr. Isaacs) was 
not quite prepared to endorse all that Mr. Phillips had said, 
and he ventured in one or two simple matters to differ from 
him. He gathered from the paper that Mr. Phillips had fallen 
into the by no means uncommon error of supposing the whole 
of the circumstances necessitating the laying down of a plan of 
sewerage to be perfect and regular, and that there were no 
special circumstances to be borne in mind. He had supposed 
the ground, and the inclination, and the houses, and the (base- 
ments, to be just such as he would have them if he had to fit 
them to his scheme, rather than to make his scheme fit the 
houses as they would have to be dealt with in a covered section 
of the metropolis. Fig. 5 was, in his (Mr. Isaac's) opinion, 
perfect as a diagram, and he could endorse the author's view as 
to the value of the increased scour which was got by reason of 
the form of the channel ; but that form possessed one fault, 
which in certain (by no means uncommon) circumstances in 
this metropolis, would be fatal to its use. Having charge of 
one part of the drainage of the metropolis, he would venture to 
remind Mr. Phillips that, as no doubt, he was perfectly aware, 



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FOR THE CONVEYANCE OP SEWAGE. 163 

there were certain situations where it became almost absolutely 
necessary to put the inlet from the houses on the very invert of 
the sewer, and hence it would follow that in constructing the 
channel, as was proposed in Fig. 5, they would absolutely 
diminish the chance of draining the houses which they would 
otherwise possess, if the section was of a different character. 
With regard to Fig. 6, Mr. Phillips did very wisely in going 
away from that form of crown. It struck him that it had many 
inherent points of weakness. In certain situations the crown 
would be a somewhat dangerous one, and he thought that there 
could be no question that, as between the crown in Fig. 6 and 
the crown in Fig. 7 the preponderance of utility and safety was 
very greatly on the side of Fig. 7. Figs. 14 to 17 related to 
a portion of the subject which possessed very great interest ; 
and they showed that Mr. Phillips had devoted his mind to the 
cure of a radical defect in stoneware pipes as at present manu- 
factured. He would venture again to differ from Mr. Phillips 
in his suggestion that the pipes should be lengthened. He had 
said that 2-feet lengths, as now in use, were too short, and that 
there was no difficulty whatever in that length being enlarged 
to 3 or 4 feet. He (Mr. Isaacs) would, however, ask Mr. Phillips 
to reflect that if the present 2-feet lengths of pipe had inherent 
faults, those faults would only be increased if the length of the 
pipe was greater. It must always be so in dealing with a 
material which had to be subjected, first to the influence of 
water, Mid subsequently to the influence of fire. There was no 
doubt that a large part of the fault of the present stoneware 

Eipe was the result of the firing process. Any material which 
ad to be made plastic by water, and afterwards subjected to 
fire, must come out a sunerer by the process. He was very 
glad to find therefore that Mr. Phillips nad turned his atten- 
tion to a totally different material fortne manufacture of sewage 
pipes, namely, Portland cement 

Mr. T. Buckham said he thought that Mr. Phillips had some-, 
what contradicted himself in the arguments. He advocated 
cesspools underneath the drains of houses, and afterwards said 
that if the pipes were properly laid there would be no necessity 
for cesspools. The effect of the pipes being properly laid he 
(Mr. Buckham) believed would be to convey the sewage pro- 
perly away from the houses into the sewers, and thereby remove 
any necessity for cesspools. He believed that any unhealthiness 
prevailing in a district which was drained into public sewers was 
caused by the defective- way in which house drains were laid. 
Gases escaped into the houses in consequence of the imperfect 
joints of the drains and through the sinks not being properly 
trapped. 

m 2 

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164 THE FORMS AND CONSTRUCTION OF CHANNELS 

Mr. F. E. Houghton said that upon the whole Mr. Phillips' 
conclusions mast be admitted to be correct. For the last five 
and twenty years engineers had had the advantage of seeing the 
different shapes that Mr. Phillips had laid down, and there was 
hardly a question in the mind of anyone as to which was best. 
Mr. rhillips had stated that the main drainage of London had 
not improved the collateral sewers or the district sewers. From 
that statement he (Mr. Houghton) must differ. His reason was 
that years ago, as Mr. Phillips was aware, the collateral sewers, 
as a rule, had no free outlet, or if they had, they were water- 
logged for a very large proportion of the twenty-four hours. 
Now they had a free outlet into the main sewers, and, in fact, 
now the main sewers formed a receptacle for the deposit from the 
collateral sewers, and the amount of deposit in the latter was 
very small in comparison with what it was twenty-five years ago. 
He very much douotedthat there were 600 miles of imperfectly 
shaped sewers at the present time. The statement as to 3*. 9£dL 
being the price for which the invert of defective sewers could 
be improved, he could not understand. That sum would not 
go very far at the present time. He should fancy that the 
price would be more like 15a. than 3s. 9Jd. 

Mr. James Lovegrove said that great credit was due to 
Mr. Phillips for his perseverance during the time he was sur- 
veyor to the Westminster Commissioners of Sewers. At that 
time he laboured hard to introduce the various improvements 
to which he had now referred. He (Mr. Lovegrove) must, 
however, take exception to the statement as to his invention of 
certain forms of sewers, especially with regard to the form shown 
at Fig. 8, and called the Holborn and Finsbury form. He 
regretted that the author of the paper had made such a very 
slight allusion to the inventor of the egg-shaped sewer. He 
alluded to the late Mr. John Roe. He (Mr. Lovegrove) had a 
copy of Mr. Roe's Report to the Holborn and Finsbury Com- 
missioners of Sewers, dated January, 1843, which contained 
diagrams of egg-shaped sewers, which were, in his opinion, far 
superior to the one now shown in Fig. 8. The diagrams were 
not issued to those who had to construct the sewers, but litho- 
graphs printed and issued to those who had to construct the 
sewers, and which showed a form closely approximating to 
Fig. 7. In conversations he (Mr. Lovegrove) had with Mr. Koe, 
the latter frequently mentioned Phillips' name and the various 
interviews he had nad with him in relation to the sewers of 
Westminster. He might, however, dismiss that part of the 
subject by simply saving that if Mr. Phillips would kindly recal 
the interviews which he had had with Mx. Roe, he would do 
more credit to the real designer of the egg-shaped sewer. 

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FOB THE CONVEYANCE OF SEWAGE. 165 

Mr. Roe also introduced the system of flushing, which could 
not now be dispensed with, no matter what form of sewer be 
adopted. He also introduced an improved form of gully and 
ventilating shaft. 

With regard to the other diagrams, Figs. 1 and 2, showing the 
semicircular bottom sewer, were well mown in the year 1848, 
and no doubt there were considerable lengths of thiat form of 
sewer still existing. The form in Fig. 4 approximated so nearly 
to Fig. 6 that he need not refer to it. The hyperbola (Fig. 5) 
was a form which he certainly thought would oe objectionable 
in some instances. He agreed with the remarks of the last 
speaker with regard to that sewer. There were some places 
where it was needful to lay a drain to every inch of depth which 
they could obtain between the normal sewage flow in the sewer 
and the lowest point to be drained within the house. He quite 
agreed with the author as to the policy of abandoning the per- 
forated stoneware blocks, shown in Fig. 12. He had adopted 
instead of them either the solid form of sewage blocks, or, 
where the ground had been sufficiently dry, bricks laid in 
courses. He preferred the latter, because he found a great 
difficulty in securing a thoroughly tight cross-joint with the 
blocks. Within the last three years he had had occasion 
actually to plug the cross-joints of the invert blocks of a sewer 
with hemp, in order to shut out the land springs, and after 
plugging those joints he succeeded by the aid of Portland 
cement in stopping the issue of land-spring water into the sewer. 
He feared that the introduction of a large burnt-clay block as 
suggested would be too costly to be carried out. The suggestion 
in Fig. 13 of lining the bottom of old sewers was a very old one. 
He remembered seeing it in several Blue Books. In all pro- 
bability it emanated from the author of the paper. He (Mr. 
Lovegrove) understood the author to state that he was the first 
to introduce the siphon-trap to gullies with the air ventilators 
to the tops of houses. He (Mr. Lovegrove) regretted that he 
had never met with that suggestion in any shape whatever. He 
introduced, some thirteen or fourteen years ago, the means of ven- 
tilating sewers by passing fresh air into the sewers through air- 
supply valves, and forming exit-shafts above the tops of the houses, 
so that the mode of ventilating sewers with high shafts was 
not a new one. The question of drain-pipes carried the memory 
back to the time when they had to decide the question of brick 
versus pipe. Any method that tends to improve the system 
of joining pipes should receive attention. There was, however, 
one thing which he wished to ensure if possible. He believed 
that whatever form of pipe was used, engineers would not 
succeed in getting good drains without a thorough supervision. 

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166 THE FORMS AND CONSTRUCTION OF CHANNELS 

Nearly all the defects were traceable to bad workmanship. 
Even with the common spigot form of pipe, a thoroughly good 
sound drain could be made if the men would but be careful. 
With regard to drains generally, even if they got a thoroughly 
good drain, they were not secure from the evils resulting from 
the present system of conveying fecal matter into the sewers. 
The other day he found in a house, rented at 65Z. a year, two 
dry sinks, bell-trap without water, and beneath the scullery sink 
another bell-trap intended to receive the washings of the entire 
surface, but as the surface was simply wiped with a flannel, the 
trap was perfectly dry and the stench abominable. That state 
of things, it was feared, existed in many of the better class of 
houses. People depended on the local authorities too much ; 
every occupier should be his own sanitary inspector, and inspect, 
discover, and remedy every cause of bad smell. It was not 
generally known that sanitary inspectors only visited houses of 
a lower class except when complaint was made. The first thing 
he did was to remove the sink and cement down the opening, 
for he held that no sink should be placed in any sheltered 
position where water might not reach the trap, and that such 
surface should be cleaned with flannel or mop. 

He believed that the subject of collection and removal of 
sewage was in a state of transition. The author mentioned 
three systems, the water-carriage, the dry-earth system, and 
the suction system. The suction system was new and could 
hardly be said to be in vogue. He believed that before long 
they would have a system that would not rob them of the water 
required for domestic uses, and which would be fraught with far 
less evil than the system which now obtained. The water- 
carriage system involved much difficulty, as in some towns they 
hardly knew whence to get the water for the water-closets, and 
when the water had been obtained and made dirty, they did 
not know what to do with it nor where to convey it. He was 
inclined to think that a system of sewage which would utilize 
the valuable elements of nutrition for plants used for the sup- 
port of life would eventually supersede the present system. 

Mr. Baldwin Latham said : With reference to the observa- 
tions of the last speaker, as to who was the designer of the 
egg-shaped sewer, which was known as the Metropolitan Sewer, 
he (Mr. Latham) had given yery great attention to the history 
of sanitary matters in this country, and he believed from his 
investigations that the design was entirely due to Mr. Phillips. 
That form of sewer was mentioned as Mr. Phillips' invention 
in the evidence given before the Metropolitan Sanitary Com- 
mission in 1847. That was sufficiently soon after the invention 
to show conclusively that Mr. Phillips was the inventor. There 



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FOB THE CONVEYANCE OF SEWAGE. 167 

was no need to say one word against the late Mr. John Roe, for 
no person could appreciate more than did he (Mr. Latham) the 
valuable services which Mr. Roe rendered to sanitary science. 
He was the first who thought of ventilating a house drain, and 
he was certainly the first to adopt the system of flushing sewers, 
by which thousands of pounds were saved by the metropolitan 
vestries, and men were rescued from the degrading occupation 
of emptying the sewers of foul matters. 

As to the improved forms of sewers which had been described, 
the previous speakers had not said one word against them, 
except that they were not applicable where he (Mr. Latham) 
thought they were most applicable. Nothing had been said to 
show that the hyperbolic form in Pig. 5 was not most perfect. 
He believed that it was so, and that it was well adapted to 
improve the ill-constructed London sewers, even where they 
were almost upon a level with the basements, as at those parts, 
by a readjustment of the levels, the bottoms could be lowered. 
Mr. Phillips had shown what were the best forms of channels 
for the conveyance of sewage by gravitation. They were uni- 
versally applicable, and therefore could be employed as well in 
London as elsewhere. There was great reason to believe that 
improvements were required in the form and construction of the 
channels of the London sewers, and no reason had been shown 
why a form which was known to be perfect, both practically and 
theoretically, should be condemned. It was well known that, 
hundreds of miles of sewers in the metropolis were disgraceful 
as sewers. They were little better than elongated cesspools, 
for they continually accumulated deposit, which continually 
required to be flushed away. There were also thousands of 
miles of private drains constructed of bricks, which were not 
only rotten, but let out the sewage and were perforated by rats. 
He bad been called to examine houses in the West End in 
which such drains existed. He could point out even a royal 
residence, in which he found a cesspool at the foot of the grand 
staircase. That was not an exceptional state of things in the 
West End. If such a thing coula exist in a house of that cha- 
racter, what might be the state of things in other houses? 
There were thousands of cases in the metropolis where sinks 
communicating with the drains under the basements of the 
houses were without traps, and the gases were constantly escap- 
ing into the habitations. During the last twelve months he 
had visited houses in the centre of London, in which there had 
been typhoid fever. One such house was within a stone's throw 
of St. Paul's Cathedral; another was at the premises of a 
banking firm, one of the partners in which had nearly lost his 
life through a severe outbreak of typhoid. These were only 



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168 THE FORMS AND CONSTRUCTION OF CHANNELS 

typical. instances. Many of the sewers, as had been said over 
and. over again, instead of being sewage-carriers, were simply 
sewers of deposit. 

As to the forms of sewers, there could be no doubt that, 
taking a given quantity of sewage, and putting it into a channel, 
the higher they could elevate its surface above the bottom of 
the sewer the greater would be the velocity of the flow. The 
velocity depended, not upon the inclination of the channel, but 
upon the gravitating effect which was due to the inclination of 
the surface of the stream. That being so, it was quite clear, 
looking at the segment-shaped channel in Fig. 2 and the 
hyperbolic channel in Fig. 5, that the relative depth being far 
greater in Fig. 5 than in Fig. 2, the difference in depth repre- 
senting a difference in fall for any given length, the velocity 
must be far greater in Fig. 5 than in Fig. 2. That was what 
Mr. Phillips had found by experiment and practice, and that 
was what he was supported in by theory. With regard to the 
form in Fig. 1, it could hardly be imagined how such a shape 
came to be used ; but he believed that it was introduced in 
1667, in the nineteenth year of the reign of Charles II., by the 
"Act for .Rebuilding the City of London." Previously to that 
flat-bottomed sewers had been used. After the reign of 
Charles II. there were successive improvements, till Mr. Phillips 
introduced the shape shown as the Westminster egg-shaped 
sewer, Fig. 6. Some persons had made objection to that form, 
thinking that it was not sufficiently strong, but it had great 
advantages in some positions. He (Mr. Latham) was just 
making a mile of sewer, with a crown of that particular shape. 
The sewer would be in a tunnel, where he desired only a certain 
width, but as great height as possible was necessary, in order to 
afford the men facility in constructing it. In adopting that 
shape, which was almost an ellipse with the major axis vertical, 
he obtained strength and height with a small expenditure of 
extra material, and in a tunnel he got the great advantage 
of height for the men to pass through it Hence there were 
points to recommend this particular form. Mr. Phillips had 
shown that the inverts in Figs. 6 and 7 had been universally 
adopted. 

Fig. 10 was an entirely new form, which had never been 
introduced until he (Mr. Latham) adopted Mr. Phillips' idea 
with regard to that form. It was an egg-shaped sewer, the 
channel of which was almost hyperbolic, as shown in Fig. 5. 
It would also be observed that the channel, where the run of 
sewage occurred, was very much smaller than in Fig. 7, yet 
that sewer was perfectly proportional. It was well known that 
in Fig. 7 the vertical diameter was one and half the 'transverse 



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FOB THE CONVEYANCE OF SEWAGE. 169 

diameter, and that the radius of the bottom was one-fourth the 
transverse diameter, the sides being struck with a radius equal 
to the vertical height. In the case of Fig. 10, the proportion 
was exactly the same. The sewer was one and half the height 
of the transverse diameter, but the radius of the bottom was 
one-eighth of the transverse diameter, instead of one-fourth, as 
in the former sewer, while the radius of the sides was one and 
one-third of the transverse diameter. Those curves gave a 
perfect form of sewer. Every curve met tangentially, just as 
it did in Fig. 7. Therefore, looking at the increased curve line 
iu the sides and the narrowed channel which elevated the flow 
and increased its velocity and scour when that was most re- 
quired, it was a sewer which must commend itself to engineers, 
and it was one entirely new. It had its origin within the last 
eighteen months, and he believed he was the first engineer who 
had adopted it. 

With regard to Fig. 11a, they would perceive an adaptation of 
the same proportional parts of the invert to the branches. A 
brick arch was thrown on the invert, so as to form a propor- 
tional sewer, and even taking the proportions as given by Mr. 
Phillips, it was possible to adjust them so as to make the sewer 
of any size, until the egg-shape shown in Fig. 10 was reached. 
In that way sewers might be made of any capacity with 
parabolic or hyperbolic channels. Where there was sufficient 
depth, and it was wished to have a sewer with great capacity, 
the very narrow invert shown in Fig. 11 might still be adopted, 
and the sides splayed out still more, throwing the crown over 
them so as to get the same capacity that would be got with a 
much deeper sewer. 

As to invert blocks, he had adopted solid blocks, which were 
of the form represented in Figs. 10 and 11a. Each block had a 
groove all round it, so that, when the blocks were brought 
together, a key of Portland cement was formed completely 
round every block, in addition to the ordinary joint. Those 
blocks, executed in blue terro-metallic material glazed, cost la. 
per superficial foot They were delivered at that price at least 
one hundred miles from the place of manufacture. Hence the 

Erice of those blocks was no drawback to their use. The blue 
rick blocks were far less liable to warp in manufacture than 
the ordinary hollow stoneware blocks that were used in the 
inverts of sewers. He had used the hollow blocks, and he 
regretted that he was persuaded to do so. He should never 
use them again. The solid block was cheaper, stronger, more 
durable, and better adapted for the work. Few people were 
aware of the extent to which the bottoms of sewers were worn 
away in the course of time by the eroding action of sewage, of 

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170 THE FORMS AND CONSTRUCTION OF CHANNELS 

street detritus, and of other substances. It was therefore a 
very important point to place in the inverts of sewers a material 
which would withstand the wear and tear to which they were 
subject. Such a material was got in the blue terro-metallic 
block. It was better adapted than any other, and there was no 
patent to restrict its use. 

Up to the present time there had not been given to the form 
and construction of channels for drains and sewers that amount 
of attention and care of which they were deserving, seeing how 
much the health of the inhabitants of towns depended upon the 
perfect and speedy removal of soiled water of every kind, and 
of fecal matter by such channels. When they found a gentle- 
man like Mr. Phillips, who had specially studied the question, 
coming forward to give the profession the benefit of his expe- 
rience, they must feel deeply indebted to him. His paper 
conveyed a large amount of information, and even those who 
were not interested in that particular branch of engineering 
must be interested in the health and well-being of the com- 
munity. If they were to compare the sewers in their own 
localities with those which had been described by Mr. Phillips, 
they could easily find out whether anything was wrong with them. 

As to the pipe-joint, made of Portland cement, he thought 
that it would recommend itself. Bound the spigot end of the 
pipe there was a projection equal to the socket on the opposite 
end, so that both the spigot and the socket of each pipe bore 
equally on the bottom of the trench. In the pipes as now 
constructed the socket was made very much larger than the 
spigot, and consequently, when the spigot was put in there was 
a vacant space all round it, which was generally filled with clay. 
Very often the clay was imperfectly placed or forced into the 
socket, but the moment the trench was filled in, the weight of 
the ground on the pipes forced the clay out of the under part 
of the joints, and the pipes at once had an irregular floor for 
the flow of the sewage ; and that irregularity was such that, 
unfortunately, there was always a break or projection at each 
joint which met the flow, for, as the sockets were generally laid 
uphill, and the spigots pointed downhill, bits of stick, or other 
hard substances, were arrested and stopped by the projections, 
and formed nuclei of obstructions. Nearly all the stoppages of 
pipe-drains and sewers occurred through the breaks or pro- 
jections at the joints, in the way he had po'nted out. The 
improvements which Mr. Phillips had suggested, in regard to 
the form, manufacture, and jointing of these pipes, were those 
which engineers had been gradually arriving at. 

Mr. W. Schonhetder said that while he quite agreed as to 
the great disadvantage which existed in the present pipe being 

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FOB THE CONVEYANCE OF SEWAGE. 171 

so short, and so badly jointed, and thus offering obstructions to 
the flow of the sewage, he should like to ask whether there 
would not be some disadvantage in making pipes very long and 
very rigid, and joining them very rigidly. Many of the sewer- 
pipes, especially the smaller ones, were laid very near the 
surface of yielding ground. Would not the settlement of the 
ground in such a case be liable to break the pipe, and allow the 
sewage to leak out ? In those special circumstances, would not 
shorter pipes, flexibly jointed, give better results ? It seemed 
to him an important point whether or not the pipe was laid in 
made ground which was not perfectly solid. 

Mr. Peregrine Birch asked Mr. Phillips the lengths of the 
experimental channels which were made of the parabola, hyper- 
bola, and elliptic segment. He thought that they must have 
been short, or there would not have been found in the case of 
No. 5 a more rapid flow than in No. 4. The author had said 
that the flushing was not at all necessary if the sewers were 
laid with proper inclinations, so as to giye a flow of 2\ feet 
per second. He (Mr. Birch) thought that there were very few 
country places where a flow of 2£ feet per second could be 
obtained down to the outfall. With regard to the false invert, 
represented in Fig. 13, he thought that if such an addition 
were made to some of the old metropolitan sewers, to render 
the normal flow effective in scouring the sewer, the abnormal 
flow would flush the streets. The greater part of the sewers 
were already none too large. Mr. Phillips had said that No. 15 
was a proper form, and he would like to see it in use. He 
(Mr. Birch) had laid three or four miles of pipe exactly that 
shape, and about the same size as Fig. 15. He was told before 
he laid it that the objection to such pipes was their twisting and 
warping during manufacture, and that he should wish that he 
had never had anything to do with them. That had been told 
to him by a manufacturer of the ordinary earthenware pipes, 
but he had them made of fire-clay, and the result was that he 
did not find any pipe that would not fit the last one laid. There 
came the abjection which Mr. Phillips and other speakers had 
mentioned, as to the spigots not fitting the sockets concen- 
trically. He (Mr. Birch) made them do so by caulking every 
joint, just as a water-pipe would be caulked. A piece of tarred 
yarn was put round the spigot He ascertained the thickness, 
and had it chiselled up, just as a water-pipe would be. The 
yarn was kept in place by a rough fillet of cement. The result 
was a sewer which had stood a pressure of 4 feet of water the 
whole night without any perceptible leakage. The additional 
cost was very slight indeed, only about 30Z. worth of yarn being 
used in four miles of sewer. It prevented the frill of cement 

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172 THE FORMS AND CONSTRUCTION OP CHANNELS 

which had been spoken of occurring inside* the pipe. With 
respect to the use of longer pipes, he thought that they would 
add materially to the labour of putting down. A 12-inch pipe, 
2 feet long, was as much as a man could handle comfortably in 
a trench. If the length was increased to 3 or 4 feet, the pipes 
would be very difficult to lay. He would ask Mr. Latham the 
thickness of the solid invert blocks he used for his sewers. 

Mr. Buckham asked Mr. Phillips if he would state the flow of 
sewage at a specified gradient through the different sections he 
had experimented with. 

Mr. Latham, in reply to Mr. Birch, said that the blocks 
which were used were 4£ inches thick, and they had a groove 
at the ends, as well as at the sides. With regard to clay- 
jointing, he had never used it. He had laid hundreds of miles 
of pipes jointed with gasket and Portland cement. The gasket 
was lapped round the spigots, which were then forced home 
into the sockets. The vacant space around the joints was then 
filled with cement, a fillet of wnich was formed round the out- 
side. With regard to the remarks of Mr. Buckham, he did not 
know how Mr. Phillips could put into a paper the information 
which was asked for. The calculations required to answer the 
question were so elaborate, that they would take a long time to 
work out. 

Mr. Buckham said his object was to know which was the best 
form of sewer for carrying away sewage most rapidly, without 
reference to the strength of construction. 

Mr. F. W. Bryant reminded Mr. Buckham that the author 
had stated the best form to be shown in drawing No. 5. 

Mr. J. Phillips, in reply to the discussion, said that there 
was one remark which fell from Mr. Lovegrove upon which he 
wished to make an observation. Mr. Lovegrove had stated that 
the improved gully and shaft which he (Mr. Phillips) originally 
used in the metropolis were invented oy Mr. Roe. He (Mr. 
Phillips) begged to say that in those respects Mr. Lovegrove 
was perfectly mistaken. He (Mr. Phillips) himself originally 
invented and introduced that gully and sewer. His gully was 
for the purpose of keeping the street detritus out of the sewers. 
Mr. Roe's was for receiving it into the 6ewers through the 

? lilies, and then washing it awav by flushing. He (Mr. 
hillips) had never consulted Mr. lioe either as to the inven- 
tion of the gully, or of the egg-shaped sewer which he (Mr. 
Phillips) had introduced. With regard to the question of 
whether the pipes should be made longer than 2 feet, he 
believed that it would be a great improvement to make them 
longer, as then they would be stronger and better able to bear 
the pressure which would come upon them. They might be 

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FOR THE CONVEYANCE OP SEWAGE. 173 

made in 3 feet, 4 feet, or even 5 feet lengths. The joint was 
the weakest part of a pipe sewer, and therefore if the pipes 
were made 3 feet, 4 feet, or 5 feet long, there would be less 
weakness in the sewer. As regarded the velocities of the flow 
through parabolic and hyperbolic channels, that subject, as 
Mr. Latham had justly stated, would take a very long time to 
work out into the form of tables which would be sufficient 
to determine what the inclinations ought to be. True velo- 
cities could only be arrived at by experiments, and improving 
the formulae which were applicable to the purpose. With 
regard to the lengths of the channels which ne made in the 
Westminster sewers, he was unable to state now what they .were. 
Those channels were made in 1844, and he thought the lengths 
ranged from 100 to 300 feet. He caused the sewage running 
in the sewers to flow through the channels. There were other 
forms besides those he had mentioned. He devoted every spare 
hour he had in ascertaining and calculating the velocities of 
the flow in the sewers, and also in the channels which he had 
made, in order that he might arrive at a judgment as to the 
velocity of flow necessary to prevent deposit, and the best form 
of channel to be adopted for the conveyance of sewage. The 
form which he had arrived at at that time, as the result of 
those observations, was represented in Figs. 6 and 7. The best 
channel for carrying off sewage, irrespective of the quantity, 
was either the parabola or the hyperbola, and not the semi- 
circle. If the water-carriage system is to be improved, either 
the one or the other of these forms should be adopted. 

The President, in closing the meeting, gave a summary of 
the various observations which had been made throughout the 
discussion, and added that they must all agree that the dis- 
cussion had been a very interesting one. 



THE END. 



FBIKTBD BY WILLIAM CLOWES AKD SONS, STAMFORD 8TRVRT AND CHARING CROSS. 



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tiXQet ^ a tTiT-n promptly* 

please return p* vu *^