1864 made its use permissable, and it is for the leaders in the
various trades most concerned to take the next step, and certainly
to no trade is it so important as to that of the mechanical engineer;
and it is for him to attempt its introduction. It is simply a
question of rules, callipers, standards, drills, and reamers, which,
after all, is not very serious. The equivalents can be made from
existing standard leading screws in lathes by means of change
The mention of screws at once calls attention to the most serious
part of the suggested change; but that difficulty can be easily met.
It would be worse than folly to attempt at present to change the
standard pitch and form of screw threads so admirably standardized
Much as one would wish to see the metric system adopted in its
entirety, it would be well at present not to advocate any departure
from the Whitworth standard thread. The two systems can and do
work admirably together side by side in many shops in France,
Germany. Russia, and Sweden.
Much has been said lately about the metric system being made
compulsory. Parliament has made it permissible, private initiative
should demonstrate that it is practical, and should then call upon
Parliament to make it compulsory. It would be a mistake to say
two years a period that has been advocated. Twenty years
would be nearer the period.
In conclusion the author added briefly his own experience. For
the past twenty-five years the metric calliper-gauge has been often
quite as familiar in the tool room at the Albion Works as the inch
one, and very little difficulty has been met with from the men. In
the engineering works in Russia, in which he is interested, both
metric and English standards are used, and little difficulty is ex-
126 THE ADOPTION OF THE METRIC SYSTEM IN OUR WORKSHOPS.
perienced in their joint use. At the new workshops just com-
pleted at the author's works in Leeds for the manufacture of the
De Laval steam turbine, the metric standard has been adopted
in combination with the Whitworth standard of thread.
The meeting was then adjourned, and the Discussion on Mr.
Greenwood's paper was taken on the following day.
THURSDAY, 5th SEPTEMBER, 19O1.
Mr. WILLIAM H. MAW, President, in the Chair.
Discussion on Mr. Greenwood's paper.
The following members took part : The Chairman, Mr. W. H.
Allen, Mr. Hans Renold, Col. P. E. Huber, Professor Archibald
Barr, Professor Schroter, and Mr. F. Howard Livens.
The author replied, and on the motion of the Chairman a vote
of thanks was accorded to him.
"THE loo-TON UNIVERSAL TESTING MACHINE, WITH
VARIABLE ACCUMULATOR, AT THE JAMES WATT
LABORATORIES, GLASGOW UNIVERSITY."
Paper by J. HARTLEY WICKSTEED.
THE straining frame of thir. testing machine is worked by
a hydraulic ram supplied with water from an accumulator.
When the valve between the hydraulic cylinder and the
accumulator is open full bcre, a test can be made at the
rate of- 100 inches straining per minute, but the valve can be
regulated so as to reduce the speed to a tenth of an inch per minute.
The speed is under easy control through a wide range, and it can
be altered at pleasure during the progress of a test. Thus the
speed may be slow until the elastic limit is reached, and increased
during the plastic stage. This facility for varying the speed,
together with the absence of all vibration, makes a hydraulic
straining gear worked from an accumulator preferable to any other
system. It is due to Dr. Kennedy to state that he advocated this
system in 1885, and stated in a paper read before the Institution
of Civil Engineers (*) that " probably the maximum in steadiness
as well as of convenience in working will be found in some such
The machine consists essentially of a straining system em-
braced by a weighing system. The straining system consists
* Proceedings Institution of Civil Engineers, Vol. IxxxviiL, page 21.
128 THE 100-TON UNIVERSAL TESTING MACHINE
of the hydraulic cylinder, ram, and notched frame which
slide out, carrying the straining crosshead A. The weighing system
consists of two long parallel rods with the three crossheads or
weighbridges B, C, and D. This parallel frame floats on knife
edges. Whatever force comes upon the weighbridges C and D is
communicated through the crosshead D to an elbow lever E, the
fulcrum of which rests on an anvil at the back of the hydraulic
cylinder. The elbow lever communicates the force to the back
centre of the steelyard lever above it. The poise-weights on the
steelyard measure the forces. In tension tests the specimen is
placed between A and C. For compression it is placed between
A and B, and if it is placed between C and F it is tested in
deflection. The crosshead A, being movable in the notched frame,
can be adjusted so as to take long or short specimens either in
tension or compression. Upon the ram there is a large nut which
can be screwed up tight against the end of the hydraulic cylinder,
so as to hold the straining frame out for an unlimited time inde-
pendent of any leak-off of the water. This device, which enables
one to keep the load upon a specimen all through the night or
through a vacation, was first introduced for Professor Archibald
Elliott, who put down the first loo-ton machine having this pro-
vision at the University College, Cardiff.
The torsion apparatus is placed at the back of the main fulcrum
of the lever. It is entirely out of the way, and has
no connection with the machine except through the torsion
specimen itself when it is in position. The torsion gear will exert
a twisting moment of 224,000 inch-lbs., and will twist in two a bar
of iron 2\ inches in diameter.
The deflection apparatus has swivel supports to prevent
indentation, and the presser-foot also has swivelling half-
round pieces which spread the pressure over 6 inches
of surface, while still allowing the specimen to bend freely; so that,
if the distance between the centres of the semi-circles is taken, the
test is theoretically the same as if the beam were supported on knife
edges at that distance apart, while injury to the section by too
intense local pressure is prevented.
The steelyard of this machine has an arrangement of poise-
weights which is a combination of the variable jockey-weight
starting from the centre of the steelyard, as introduced by Dr.
Kennedy on a 5o-ton machine, the first of this type, which he put
down in his laboratory in Westminster, and of the solid poise
ranging over both arms of a double-armed steelyard which the
author has used for many years. This combination has been
arranged to meet Dr. Barr's desire for a larger scale unit when
measuring light loads, and has the effect of giving the same scale
unit up to 100 tons, which was obtained on Dr. Kennedy's machine
AT THE JAMES WATT LABORATORIES. 129
up to 50 tons, without materially lengthening the steelyard. When
the machine is being used for loads up to 32 tons, the large
poise-weight remains stationary at the short end of the lever, and
acts merely as a balance weight to the long end. The variable
poise starts from the centre of the lever and travels over the long
arm with a scale reading of 4 inches to the ton up to 32 tons.
This poise-weight has two removable discs, which reduce it
by half, giving a scale reading of 8 inches to the
ton up to 1 6 tons. When the specimen requires more than
32 tons of load, this second poise is lifted clear away from the
machine. The balance of the steelyard is not affected owing to
the latter being lifted off the line of the fulcrum. The main
poise-weight is then liberated from its fixing to the steelyard and
engaged with the traversing screw, and travels over the whole
range of the steelyard, giving a scale reading of 2 inches to the ton
up to 100 tons. At the suggestion of Dr. Barr, these poise-weights
ride upon three wheels, of which the two on one side have flanges
working in a groove in the rail of the steelyard, to keep the poise
from wavering sideways, and a plain single wheel on the other side
to support the poise vertically, thus forming a " geometrical guide."
There are two scales on the steelyard, one for use with the large
solid poise, and the other for use with the variable poise. The
poise-weights carry venier scales, which, at the suggestion of Dr.
Barr, are attached by hinges to the poise-weights, and rest by their
own overhanging weight in V grooves on the scale bar. This
insures that the venier scale is always lying close up to the marks
of the main scale without the possibility of being injured from want
of clearance by the vibrations of the steelyard following upon the
fracture of a test piece.
The accumulator has a variable load consisting of ten 4-ton slabs,
of which it can deposit any number up to nine on the base, and
carry up the remainder. The slabs which it is desired to load on
are, at the suggestion of Dr. Barr, hung from the top weight by
three rods. This arrangement has been adopted not only on
account of its advantages in connection with the testing machine,
but to enable the accumulator to be used in connection with other
pieces of apparatus, and to increase its value as an apparatus upon
which efficiency tests under a great variety of circumstances may be
The following members took part in the Discussion : The Chair-
man, Professor Archibald Barr, Mr. Arthur Greenwood, and
Professor W. Cawthorne Unwin.
The author replied, and on the motion of the Chairman a vote
of thanks was accorded to him.
"A REGENERATIVE ACCUMULATOR AND ITS APPLI-
CATION FOR USING EXHAUST STEAM."
Paper by A. RATEAU.
THE new apparatus referred to in this paper is intended to allow,
in a turbine or any other motor, the use of the exhaust steam from
machines having intermittent action, such as winding engines or
the reversible engines of rolling mills. Engines with intermittent
action are well known to be defective in respect of the satisfactory
use of the steam, caused by condensation within the cylinders.
This inconvenience has no doubt been to a small extent remedied
by compounding and also by condensing ; but the advantage gained
is much less than can be obtained by using the steam at about
atmospheric pressure in a turbine provided with a condenser.
The Hon. C. A. Parsons has already urged the use of turbines
with low steam pressure, attached to continuously-running steam
engines. For instance, if we take a winding engine using
45 kilogrammes (99 Ibs.) of steam per B.H.P. (titile), which is
about the maximum for non-compound engines without condensa-
tion, these 45 kilogrammes of steam are sufficient to give, in a
steam turbine coupled to a dynamo, an electric power of at least
two H.P. ; by the application in this case of the regenerative
accumulator system, two horse-power is added to the one horse-
power of the winding engine.
The difficulty which this apparatus solves is the following :
The turbine requires to be supplied with a continuous flow of
steam, whereas the engine working intermittently delivers it at
more or less regular intervals of one or two minutes. A reservoir
is therefore required between the two engines. An ordinary
reservoir would have excessive dimensions, whilst with the
apparatus about to be described this excessive size is avoided,
and the cost of erection is relatively small.
This apparatus, which may be called a " regenerative steam-
accumulator," serves the purpose of a reservoir. The solid and
liquid materials, which it contains, form a storage in which the
steam gathers and condenses when arriving in excess, and sub-
sequently re-evaporises during the period when the main engine
slackens or stops. The variations in temperature necessitated by
the condensation and re-evaporation of steam correspond to the
small fluctuations of pressure in the accumulator. The pressure
A REGENERATIVE ACCUMULATOR. 131
rises while the apparatus is filling, and falls while it is being
emptied. The amplitude of these temperature and pressure
oscillations is not great, 3 deg. to 5 deg. C., and o.io to 0.15 kg.
per cm 2 (1.4 to 2.1 Ibs. per square inch). This variation can be
limited to any desired range by designing the apparatus sufficiently
large in accordance with the periods of running and standing of
the main engine.
The apparatus consists of cast-iron annular basins placed one
above the other, inside a cylindrical vessel of sheet iron. The
steam, which enters the vessel by a pipe near the top, reaches the
basin by the central channel. The portion which is not con-
densed, as well as that which is re-evaporated, descends along the
lateral partitions of the vessel, and reaches the pipe leading to the
The water carried away by the steam separates out in the upper
chamber and falls, first through holes in the top plate, thence from
basin to basin by the passages in the overflow to the bottom of the
vessel, whence it is discharged by the small pipe, and an automatic
steam-trap. The basins are thus always covered with water.
The apparatus is completed with a safety valve and an automatic
steam-valve for assisting the turbine by steam direct from the
By means of this accumulator it is possible to obtain in an
ordinary-sized winding-engine plant, an additional motive power of
about 500 H.P., with no expense but the cost of installing the
turbine and accumulator, which is not great.
An application of 250 H.P. is now in course of erection at the
Bruay Mines in the North of France, and will be working in a few
The discussion was combined with that on the other paper by
M. Rateau (see p. 133).
EXPERIMENTS ON THE ESCAPE OF STEAM
THROUGH CIRCULAR ORIFICES."
Paper by A. RATEAU.
THE design of steam turbines depends upon the knowledge of
the laws which determine the escape of steam through converging
or converging-diverging orifices. In order to verify exactly the
formulas for the escape of steam, the author undertook, in 1895-
1896, at St. Etienne, a series of experiments on this subject, accord-
ing to a method which gives the greatest possible precision. A
short indication of these experiments has been given in the report
on steam turbines which the author had the honour to present last
year at the International Congress of Applied Mechanics in Paris.
But at this time he had not yet completed all the calculations of the
results of his experiments, whereas now he is able to give an
account of the results. They differ a little from those the author
provisionally announced at the Congress of 1900.
Those investigators who experimented before and since the
author, namely, Minary and Resal in 1861, Peabody and Kunhard
in 1890, Parenty in 1891, Miller and Read in 1895, and Rosenheim
in 1900, have all used the same method, which consists of con-
densing in a surface condenser the steam, which escapes by the
orifice for a sufficiently long period, and then weighing the con-
densed water. But this method, beyond being very laborious,
cannot give great precision, because in the first place it is very
difficult to keep constant the initial steam-pressure during the
whole of the experiments, and the steam, being never absolutely
dry, the water which it carries with it is weighed with the condensed
water, so that the results found must be generally overestimated.
The author therefore proposed to remove these causes of error
so as to obtain exact results within two-thousandths, and to use,
besides, sufficiently large orifices to deliver up to more than 900 kg.
of steam per hour.
He has reached the desired result by condensing the steam in a
stream of water with the use of an ejector-condensor, and by
measuring the total yield of water and the initial and final
temperatures of this stream. Thus he was able to make all the
readings at the same moment, as soon as constant conditions were
ESCAPE OF STEAM THROUGH CIRCULAR ORIFICES. 133
obtained; and each experiment did not last more than one or two
minutes. It has been possible thus without much trouble to make
more than a hundred and forty observations under the most varied
The paper contains the results of the experiments and diagrams
illustrating them. The results agree satisfactorily with the theo-
A combined Discussion was held on the two papers by M. Rateau,
and was taken part in by the following members : The Chairman,
Professor A. Stodola, and Mr. Bryan Donkin.
The author replied, and on the motion of the Chairman a vote
of thanks was accorded to him.
A communication was received from Mr. Michael Longridge, to
which the author also replied in writing.
"POWER REQUIRED TO DRIVE A MARINE ENGINE
Paper by JAMES CRICHTON and W. G. RIDDELL.
IT is not the intention of the writers to attempt to describe a
model engine works or driving plant, but rather to enumerate, and
show the result of, a few improvements which have been adopted
by the firm with which they are connected.
About three years ago it was decided to rearrange the works in
a thorough manner, and to fit up a new power installation.
The works had gradually grown during upwards of thirty years,
and most of the buildings were in excellent condition, and in no
need of reconstruction. The problem to be solved then was how
to lay down an economical driving plant, which would conform to
the existing conditions, and which would not lead to an unnecessary
At that time the motive power of the works consisted of one
marine type boiler working at 80 Ibs. pressure, and supplying
steam to three vertical compound engines for driving the machinery,
and one vertical compound engine for lighting purposes.
The points in favour of so many units were (i) The saving
in steam when running one or two machines at night, which might
be driven by one of the small engines; and (2) the fact that, in the
event of a breakdown of one engine, the other part of the works
were not affected.
It was, however, decided to put in one engine capable of driving
and lighting the entire works, and, to meet the difficulty of late
work, by driving those machines which experience showed were
most likely to be needed at night, with motors which could be
connected with current from the Glasgow Corporation supply.
The engine was made to a simple design, and of such strength
as to make the fear of a break-down very remote. It is capable,
as at present constructed, of developing 260 I.H.P., but this may
be increased to 600 I.H.P.
A cylindrical marine boiler, designed to work under either forced
or natural draught, was selected as the most suitable type, and
has proved itself both economical and reliable. It has a working
pressure of 200 Ibs. per square inch, and evaporates about 9 Ibs.
of water per Ib. of coal.
POWER REQUIRED TO DRIVE A MARINE ENGINE WORKS. 135
The position of the power station was fixed, to a certain extent,
by circumstances. The works are situated in a busy part of the
city of Glasgow, where ground is costly, and economy of floor space
essential. There is no direct communication with any railway, so
that all material has to be carted to and from the works. Close
proximity to the street was, therefore, an important factor in
settling the position of the boiler. The position chosen was be-
tween the engine and boiler departments, and as the difference in
the floor level of these departments is about six feet, the boiler
was placed on the lower level, and the coal tipped over into a
bunker in front of it. The ashes were returned by a hydraulic
hoist to a receiver on the higher level, under which a cart might
be filled automatically.
The engine was placed as near the boiler as possible, with the
crank shaft parallel to two of the main lines of shop shafting.
Two dynamos were laid down for lighting and driving purposes,
and these and the two lines of shafting were connected to the main
engine shaft with belts, and all so arranged as to be easily dis-
connected. Motors were laid down to drive all outlying shafting.
The paper contains full details of the new installation and of
the tests which were carried out.
Before instituting a comparison between the old and new
systems of driving the works, it may be well to enumerate briefly
various units which made up the old installation. These were:
1. A marine type boiler, working at a pressure of 80 Ibs. per
square inch. The feed water for the boiler was heated to 205 deg.
Fahr., as in the new boiler.
2. Three compound non-condensing engines, indicating collec-
tively, say, 151 I.H.P., for driving purposes.
3. One compound non-condensing engine, for lighting purposes,,
of, say, 65 I.H.P.
The boiler evaporated about 6.75 Ibs. of water per Ib. of coal,
and the engines used 43.8 Ibs. of water per I.H.P. per hour. This
gave an average coal consumpt of 6.4 Ibs. of coal per I.H.P. per hour.
In calculating the cost of a horse power for a year, the coal used
for raising steam for smithy hammers and blower engines has not
been taken into account, but the steam for electric lighting has
been charged in each case, as it was almost impossible to obtain
accurate figures without doing so. It will be seen that the power
for electric lighting is much greater in the new than in the old
system, and it may be contended that the greater efficiency of a
horse power in the new system of driving is partly due to the
better lit workshops ; but this is a refinement into which the scope
of the paper does not admit of investigation.
It now remains to be shown by how much the new system is:
better than the old or, in other words, at how much smaller cost
136 POWER REQUIRED TO DRIVE A MARINE ENGINE WORKS.
it produces work. Since the power in an engine works is expended
in removing material from rough castings and forgings, a figure
may be found by which different systems may be compared; the
system by which the greatest weight of material is removed at the
smallest cost being the most efficient. In order to make the
grounds of comparison similar, the cuttings produced by machines
whose scrap is not in proportion to the power expended such as
shearing machines and saws are not taken into account; but the
weight of all turnings, borings, etc., for a fixed period is divided
by the cost of a horse power for the same period, and a money
value for the power per ton removed can thus be obtained. From
the tables accompanying the paper it will be seen that the cost
of removing one ton under the old system of driving was ^5.21,
and under the new system .2.48, showing a saving by the new
system of 52 per cent. Notwithstanding this great saving, it is
abundantly clear that the cost may be much further reduced.
The authors hoped that the paper may help to provide a basis on
which to calculate the relative efficiency of the driving plant in
Mr. Alfred Saxon, the Chairman, Mr. W. H. Allen, Mr. Bryan
Donkin, and Mr. E. R. Walker took part in the Discussion.
Mr. Crighton replied.
On the motion of the Chairman a vote of thanks was accorded
to the authors.
A communication was also received from Mr. Alfred Saxon.
PNEUMATIC RIVETING, AND OTHER USEFUL
APPLICATIONS OF PNEUMATIC TOOLS."
Paper by J. C. TAITE.
THE author, having been asked to write a short paper on pneumatic
tools, and having regard to the comparatively recent one, read
by Mr. E. C. Amos, (*) when a lengthy discussion followed, has
confined these remarks principally to pneumatic riveting, with
special regard to the pneumatic exhibits at the Glasgow Exhibition.
Shell Riveter. With the introduction of the " Boyer " long-stroke
hammer for shell riveting, rivets up to ij inches can be successfully
knocked down, and the pneumatic holder-up has overcome the
difficulties of the old method. The length of the paper does not
allow of a full description of the appliance. The most noteworthy
feature, however, is that the riveting hammer is mounted, and has
a travel of 3^ inches in an outer cylinder, to which air is admitted
when the hammer trigger is depressed, the pressure acting on a
collar surrounding the hammer barrel, shoots the tool forward on
to the rivet head, the notched bar at the other end of the rigging
being adjusted to provide the reaction necessary for the snap to be
continuously pressed on to the rivet, while the percussive riveting
action is performed by the hammer. The hammer with its casing
is mounted in a spherical bearing which enables it to be turned
about through any desired angle within the requisite limits.
Another and later development is the No. 9 long-stroke hammer, in