Proceedings of Societies.

-

GEOLOGICAL SOCIETY OF LONDON.

Dec. 19.-L. Horner, Esq., President, in the Many of the Vice-Presidents and Members of chair.

MEETINGS FOR THE WEEK.
MON.-British Architects, "On the Architecture of
Auvergne," by G. E. Street, Esq., at 8 p.m.
London Inst., "On the Relations of the Animal
Kingdom to the Industry of Man," by E. Lan-
kester, Esq., at 7 p.m.

TUES.-Zoological Soc., at 9 p.m.

Inst. Civil Engineers, Continued Discussion upon
Mr. Preece's paper "On Submarine Telegraph
Cables," at 8 p.m.
WED.-Geological Soc., I., "On the Stratigraphical Posi-
tion of certain Corals in the Lias," by the Rev.
P. B. Brodie, F.G.S.; II., "On the Malvern and
Ledbury Tunnels, and other Sections on the
Worcester and Hereford Railway," by the Rev.
W. S. Symonds, F.G.S., and A. Lambert, Esq., at
8 p.m.

London Inst., "On Physical Geology and Geo-
graphy," by E. W. Brayley, Esq., at 7 p.m.
Society of Arts, at 8 p.m.

THURS.- Royal Soc., at 8.30 p.m.
FRI.-London Inst., "On the Principles and Applications
of Vegetable and Animal Chemistry," by T. A.
Malone, Esq., at 7 p.m.

We ought to state that the ceremony of christen- | 135 lbs. each; and 10 rounds of solid shot of
ing the ship was performed with much heartiness similar nature, 180 lbs. each. Some of these
and good-will by Sir John Pakington, the Presi- heavier projectiles penetrated through the earth-
dent of the Institution of Naval Architects. work fired at, the thickness being 28 feet. All
these, together with the 900 rounds from the
Council of that Institution from various parts of other three heavy guns, were fired with my pro-
the country were also present on the occasion. posed service charge of 5 lbs. for the 32-pounder,
We doubt if any ship of war was ever more
and 7 lbs. for the 68-pounder. Not one of these,
admired for the beauty of her form than was the or any other service gun to which my system has
Warrior on Saturday last, both before and after been applied, is apparently the least injured by
she was afloat. The publication of an engraving the trial. The charge of powder I employ is only
of La Gloire in this Magazine on the previous half the usual service charge, but at the same time
day had familiarised many of the persons present I propose to increase the weight of projectile by
with her ugliness, and prepared them, perhaps, half as much again as the common round solid
to look with peculiar admiration upon the beau-shot-so that in fact the 32-pounder becomes a
tiful bow, and curving sides, and handsome stern 48-pounder, and the 68-pounder a 90-pounder.
of the Warrior. She is certainly a finely-formed With these proportions of charge I obtain more
vessel, and does great credit to the good taste of useful effect, but as the gun recoils considerably
her designers.
less with it than with the usual charge, I believe
that the gun is not subjected to a more severe
strain from within, and consequently not en-
dangered.

On a future occasion we hope to give a detailed account of the Warrior's construction; for the present, however, we must content ourselves with giving the following particulars concerning her, viz. :

I have not yet had the means of determining the necessary modifications of detail for obtaining the best results as regards range and precision. This will require further experiments. I give the following results of ten successive rounds fired a few weeks since, merely to afford some idea of the still better things to be looked for when the plan shall be more matured.

Practice with a rifled cast-iron 32-pounder service gun, charge of powder, 5 lbs.; shells, 48 lbs. each, capable of containing 41 lbs. bursting charge; elevation, 23 degrees, Range,

58
21

15 3
17 3
26 0

96

19 0

Recoil.

ft. in.

1250

6050

4 6

left

RIFLED CAST-IRON SERVICE GUNS.*

BY MR. BASHLEY BRITTEN.

A GOOD rifled gun is so much more efficient than
a smooth bore at any distance beyond two or
three hundred yards, that if our old guns cannot
be improved they must be all condemned. If,
however, it be possible to rifle them and to bring
them nearer to the higher standard required, vast
sums of public money might be saved, and our
defences supplied with superior weapons in a very
short time.

The following facts will be found to throw some
light on this important point,
The service guns
which have now been tested on the principle I
proposed are as follows:-Two 9-pounders of 17
cwt.: one 32-pounder of 56 cwt.; three 32-pounders
of 58 cwt.; and three 68-pounders of 95 cwt.-

all of them ordinary cast-iron service guns, taken
indiscriminately from store, and rifled in their
full-sized bore. They are not hooped or
strengthened in any way, and all the work done
in converting them may be executed in ten hours
at a cost of 20s. each gun. From the two
9-pounders, 54 rounds have been fired; from two
of the 32-pounders, 600 rounds (300 each); and
from one of the 68-pounders, also 300 rounds.
My projectiles for the rifled 9-pounders weigh
about 15 lbs., those for the 32-pounders, 48 lbs.,
and those for 68-pounders, about 90 lbs. each.
Such is the weight of projectile I propose for
service with such guns. The other four

4 6
4 6

Time of flight.

Deviation from
line of aim.

1st graze.

,, right... 5,406

21 yards right... 5,479

5,604 39

2

left

5,685

9

,, right... 5,649

5

left

5,670
5,650

right... 5,628

LAUNCH OF THE WARRIOR. THE iron-plated frigate Warrior-the largest and most formidable war-ship in the world-was launched with perfect success on Saturday last, at the works of the Thames Iron Company, Blackwall. The company who built the vessel were responsible for her safe launching, and entrusted the control of the operation to their foreman, Mr. Piddington, who carried it out in the most satisfactory manner, the chief inspecting officer of the Admiralty, Mr. J. Luke-a gentleman possessing great knowledge and experience-being on the spot to furnish such professional aid as might be required. We need hardly say that the launch of such a ship as the Warrior-a ship more than 400 feet long, 58 broad, and heavily constructed of iron-excited great interest among mechanical men, several hundreds of whom attended to witness the process. The event proved that the occasion was not without great and even unexpected interest. It was unlike all other launches which we ever saw, inasmuch as, although no absolute stoppage of the vessel occurred after her first movement, yet the progress of the ship into been subjected to a more severe trial, merely to the wa ter occupied several minutes. Had she been test their strength under the new conditions. left to herself she certainly would not have moved They were fired at Woolwich as follows:at all; yet the forces acting upon her were so 32-pounders-10 rounds, with proposed service nicelyf balanced, that on the application of a shell 48 lbs. each; 10 rounds, with shells of a powerul screw or two, she began to move, and similar nature, 72 lbs. each; and 10 rounds, kept steadily, although most imperceptibly, in with solid shot of similar nature, 96 lbs. each. motion, until two or three powerful tug steamers 68-pounders-10 rounds, with proposed shell for made fast to her steamed ahead, and gave her service, 90 lbs. each; 10 rounds of heavier shells, such a start as induced her to "glide gracefully," as the newspapers say, "into her native element." • Our readers will remember that in our review of the dis-time fuze, or by percussion at striking. Molten cussion which took place at the Institution of Civil Engi- iron shells on a similar plan may be fired from the The interest of such a launch may be readily neers some time since, we noticed the important experiments rifled gun with the same precision and range as conceived. The complete success with which it which Mr. Bashley Britten had made with rifled cast-iron was effected must have been very gratifying both guns. Since that time Mr. Britten has been "enabled by the others. The rifled gun is loaded with as much to the directors and officers of the Thames Com-scale, and the above paper (which we take from a letter of rammer, and no alteration of carriage or any extra the War-office" to continue his experiments on a large facility as the smooth bore, and with the same pany, and to the Admiralty officials and profes- consider it the most remarkable document ever yet made appliance of any kind is needed. While these his in the Daily News) gives the results of his practice. We sional persons who were present in great numbers. public in reference to rifled ordnance, points of advantage are added to these guns, it is

guns have

the same gun when converted into a rifle has It will be seen from the above figures that greater precision at a distance of nearly 6,000 The rifled gun throws shells 50 per cent. heavier yards than it had before at less than 3,000 yards.

These rifle shells will hold a bursting charge of four times than the present round solid shot. Shrapnel on the same principle may be constructed as much powder as the common smooth-bore shell. so as to break up into more than four times as rifle shells may be arranged to burst with the many fragments as the ordinary shrapnel. The

also a matter of deep importance to know that the rifled guns will be no less serviceable than as smooth bores for discharging round or common case shot whenever it might be desirable to employ them.

quired to keep up the steam. This irregularity
arose from the circumstance of the boiler top
being wholly unprotected from the weather, in con-
sequence of which, when winter came, with rain
and snow, the consumption of coal was increased
from 25 to 30 per cent. over the usual average
quantity. The experiments were therefore dis-
continued for a few days until the boiler and
steam-pipes were covered-the boiler with hair
felt and bricks, and the pipes with felt, saw-dust,
and wood.

Coals consumed
Do. per hour

32 ft. 6 in.

5 ft 2 in.

Two.

1 ft. 6 in.

61 ft.

8 ft.
306 ft.
10 ft. 7 in.

351 cub. ft,
10-028 cub. ft.
208 cub. ft.

5.94 cub. ft. 13 sq. ft.

53.5 sq. in.

25.8 cub. ft.

per horse power per hour 73 cub. ft.

Saturday, 14th January, 1860, being four weeks Time of working
in all, or 240 hours. Diagrams were taken several
times a-day, and the mean accepted as showing
the actual quantity and force of the steam in the
cylinder. M'Naught's indicator was used, and its
accuracy was occasionally tested both on the
boiler and valve casing alongside of Bourdon's
pressure gauges, the one in fact checking the ac-
curacy of the other. The coal was accurately Heat of feed-water
weighed, and the quantities recorded represent
every pound that was consumed, including the
getting up of the steam in the mornings, gather-
ing the fire at night, and on Sundays. The ashes
and clinkers were also carefully weighed.

The evaporation was tested by measuring accu-
rately the surface area of the water in the boiler,
and noting its height on the gauge glass before
starting the engine at 10 o'clock A.M., and at
2 o'clock P.M., and stopping again at 12 o'clock,
and at 5 o'clock P.M., until respectively the fall
of the water was ascertained. The engine was
stopped for the purpose of letting the water be as
quiescent as possible. This again was partially
checked by noting the quantity of water taken
from a cistern.

These rifled cast-iron guns will in one respect be certainly inferior to the new wrought-iron breechloaders. From the large size of the bore it is not possible to fire shot from them of that length and weight which at extremely high elevations afford the longest range. Up to 6,000 yards my convic. tion is that they may be rendered quite as effective On Monday, 12th December, 1859, the experi. for general purposes, and if it be possible to ments were resumed with the expansion valve set strengthen them with hoops, this range may be to cut off the steam at one-fifth of the stroke, considerably increased. But practical soldiers and were continued until Saturday, 31st December attach little or no value to this long-range vertical-three weeks; and from Monday, 9th, until fire. Sir W. Armstrong himself told his brother engineers, in the discussion, that, "however perfect weapons might be made, the fate of a battle would never be materially influenced by very distant firing. The real struggle would always lie within a distance of 2,000 yards." He farther states, according to the published report, "A shot of large diameter, by making a larger kole and producing more splinters and greater displacement, was in general more efficacious than a long narrow bolt." These rifled cast-iron service guns will consequently have the same advantage over the Armstrong medium-sized bore, as the latter is claimed by the inventor to have over the small-bored Whitworth. The larger the shell is the greater of course is its capacity for bursting charge, and there is little doubt about this being of more use than a rather longer range. The bore of the 32-pounder service gun is 6 inches diameter; that of the Armstrong 32-pounder only 4 inches. But there are other positive advantages sttaching to the old guns. They are in existence, and are paid for. They are also in the simplest possible form. They are not liable to serious injury from slight blows on external polished surfaces and screw fittings. When exposed in open batteries subject year after year to the effect of a dampings, Fig. 1 being a sectional plan, and Fig. 2 a and corroding atmosphere, it is most probable vertical longitudinal section. It is 32 feet 6 inches that this simplicity will render them far more long, by 5 feet 2 inches in inside diameter, with enduring than the others, because guns are two flues passing through it longitudinally, weldom worn out with firing; they become unser- each 18 inches in inside diameter. The fireviceable in a long course of years from honeycomb grate measures 4 feet by 3 feet 3 inches, and and decay. the ashpit is fitted with doors. On the centre of each door is a fan valve for regulating the admission of air. The wall A at the side of the grate nearest the chimney is built close up to the boiler. Their are air-holes in this wall, the air being supplied by a valve in front of the building B. This air is of course to aid in abating the smoke nuisance. The furnace bridge rises to within five inches of the boiler, allowing about 510 square inches for the passage of the gases, or about 40 inches per foot of fire grate. There is no part of the outer shell of the boiler exposed to the action of the fire excepting the part above the furnace, and onwards to where the flame turns upwards to the flue tubes. The recipient surfaces computed by the usual method are equivalent to about 23-horse power. At C, between the boiler and damper, there is another bridge which rises to a level with the centre of the tubes, the opening over it being about 300 square inches. The gases after passing this bridge descend and pass beneath the damper into the chimney. The steampipe to the engine is 49 feet long by 5 inches in diameter, and is carried through the chimney at D, where it is divided into four pipes made of copper, and joined to the iron pipe in the brickwork of the chimney. These pipes possess in all about 26 feet of surface, and may take up a little, a very little of the heat manifestly going to waste up the chimney.

STEAM ENGINE AND BOILER EXPERI-
MENTS AT THE SCOTLAND-STREET
IRON WORKS, GLASGOW,

By Mr. WILLIAM TAIT,
Tax years ago, the writer commenced a series
experiments for the purpose of verifying in
measure the advantages alleged to be de-
rived from the use of high-pressed steam, worked
are or less expansively, as compared with steam
a lower pressure, worked in the usual way.
The experiments, however, were soon abandoned,
case the engine was very often worked late,
occasionally all night, with a load at night
bably not more than one-half of that which
stituted the day's work. It was also found in
venient to attend at night to take
pressure

rams.

Similar experiments were again instied a few months ago, and although not so comeas were originally intended, they may yet interesting to those occupied with similar purThe economic conditions under which a weight of coal is made to perform a given ent of work, form an important object of

Pressure of steam in boiler...
Do.
in valve-casing
Initial pressure on piston
Average do. do.

285-6 "" 8.08 ??

5.65 3,509

5.1 per cent. 1 inch.

inch.

Wishaw dross. 124° Fahr.

40 lbs.

40 35

13.65 lbs.

10 in.

35.33

Travel of piston before steam is cut off,
nearly...
Indicated horses pwr. (usual method) viz.:
area of cylinder x by effective pressure
x ft. travelled per min.
33.000

Length of steam-pipe

Diameter of do.

Method of superheating. By 4 copper
pipes through chimney 33 in external
diameter-length 28 ft.-heating surface
Temperature of steam in boiler at 44 lbs.
Do.
in valve casing at
41 lbs....

26.4 ft. 292° Fahr. 291° Fahr. The temperature of the steam in the boiler and valve-casing was tried, for the purpose of ascerThe boiler is represented in the annexed engrav-taining whether any and to what extent heat was imparted to the steam by the copper pipes in the chimney. In the valve-casing the temperature was 1° lower than in the boiler; the one was 2° and the other 3° below what was due to the pressure. This discrepancy was no doubt owing to currents of cold air, and, at the valve-casing particularly, to the radiation of heat from the surface of the part where the thermometer was applied. At times, however, the temperatures were uniform and correct.

The engine is high-pressure, with cylinder 20 inches in diameter, and a stroke of 4 feet, and it made with great regularity 34 strokes per minute this at any rate being the mean velocity. The cylinder is not jacketed, and has no covering of any kind. The slide-valves are worked by eccentrics both for steam and expansion. Figs. 3 and 4 represent two pairs of top and bottom diagrams taken from the cylinder.

The pressure in the boiler and in the casing was indicated by Bourdon's gauges, and showed a nearly absolute uniformity-the greatest variation being from one pound to one and a half pounds; the excess being sometimes in the boiler and sometimes in the casing.

Regarding the quantity of coals consumed, it must be noted that the weather was nearly constantly wet during the experiments; the coals were brought in daily as required, and were weighed often when saturated with water; this water forming, in some instances, a large percentage. The weather also had an adverse effect on the boiler. The stock of coal in the work was kept small to prevent the temptation to any excess in firing.

The steam-space in the boiler is noted, because it is large in proportion to the quantity of steam used at a single stroke of the engine; this quantity, including the filling of the steam port, was about 24 cubic feet, which was just about one eighty-third part of the steam in the boiler. This circumstance prevented in a great measure the liability of the water to pass off with the steamwater passing off in that way accounting satisfactorily for the apparently very great success attending many experiments on record; the success being in direct proportion to the amount of priming, or water carried off with the steam. It is doubtful whether or not any material benefit was derived from so partial an attempt at superheating as was tried in the present experiments.

The heat in the flue was high, and, on several occasions, melted zine; in fact, it was melted on every repetition of the experiment if allowed to

The following facts will be found to throw some light on this important point, The service guns which have now been tested on the principle I proposed are as follows:-Two 9-pounders of 17 cwt.; one 32-pounder of 56 cwt.; three 32-pounders of 58 cwt.; and three 68-pounders of 95 cwt.all of them ordinary cast-iron service guns, taken indiscriminately from store, and rifled in their full-sized bore. They are not hooped or strengthened in any way, and all the work done in converting them may be executed in ten hours at a cost of 20s. each gun. From the two 9-pounders, 54 rounds have been fired; from two of the 32-pounders, 600 rounds (300 each); and from one of the 68-pounders, also 300 rounds. My projectiles for the rifled 9-pounders weigh about 15 lbs., those for the 32-pounders, 48 lbs., and those for 68-pounders, about 90 lbs. each. Such is the weight of projectile I propose for service with such guns. The other four guns have been subjected to a more severe trial, merely to test their strength under the new conditions. They were fired at Woolwich as follows: 32-pounders-10 rounds, with proposed service shell 48 lbs. each; 10 rounds, with shells of a similar nature, 72 lbs. each; and 10 rounds,

with solid shot of similar nature, 96 lbs. each. 68-pounders-10 rounds, with proposed shell for service, 90 lbs. each; 10 rounds of heavier shells,

Our readers will remember that in our review of the dis

neers some time since, we noticed the important experiments cussion which took place at the Institution of Civil Engiwhich Mr. Bashley Britten had made with rifled cast-iron guns. Since that time Mr. Britten has been "enabled by the War-office" to continue his experiments on a large scale, and the above paper (which we take from a letter of consider it the most remarkable document ever yet made his in the Daily News) gives the results of his practice. We public in reference to rifled ordnance,

also a matter of deep importance to know that the rifled guns will be no less serviceable than as smooth bores for discharging round or common case shot whenever it might be desirable to employ them.

quired to keep up the steam. This irregularity
arose from the circumstance of the boiler top
being wholly unprotected from the weather, in con-
sequence of which, when winter came, with rain
and snow, the consumption of coal was increased
from 25 to 30 per cent. over the usual average
quantity. The experiments were therefore dis-
continued for a few days until the boiler and
steam-pipes were covered-the boiler with hair
felt and bricks, and the pipes with felt, saw-dust,
and wood.

The following are the data and mean results of four weeks' observations :

Length of boiler
Diameter of do. (internal)
Number of flues
Diameter of do. (internal)

Area of under surface of boiler exposed to
the fire

Do. end of boiler exposed
flues

...

$2 ft. 6 in.

5 ft 2 in.

Two.

1 ft. 6 in.

61 ft.
8 ft.
306 ft.

Heating surface per indicated horse power 10 ft. 7 in.
Quantity of water in boiler (6 in. above

flues)

Do. per horse power

Steam space in boiler

Do. per horse power

Area of fire-grate

Do.

per horse power

Water evaporated per hour...

Do.

Time of working
Coals consumed
Do. per hour

351 cub. ft. 10-028 cub. ft. 208 cub. ft. 5.94 cub, ft.

per horse power per hour 73 cub. ft.

240 hours,

Do. per horse power per hour
Pounds of water evaporated per pound
of coal

Clinkers and ashes

Per centage of do. to the coals consumed
Thickness of fire-bars
Spaces between do.
Description of coal used
Pressure of steam in boiler...
Do.
in valve-casing
Initial pressure on piston
do.
Average do.

These rifled cast-iron guns will in one respect be certainly inferior to the new wrought-iron breechloaders. From the large size of the bore it is not possible to fire shot from them of that length and weight which at extremely high elevations afford the longest range. Up to 6,000 yards my convic. On Monday, 12th December, 1859, the experi. tion is that they may be rendered quite as effective for general purposes, and if it be possible to ments were resumed with the expansion valve set strengthen them with hoops, this range may be to cut off the steam at one-fifth of the stroke, considerably increased. But practical soldiers and were continued until Saturday, 31st December attach little or no value to this long-range vertical-three weeks; and from Monday, 9th, until fire. Sir W. Armstrong himself told his brother Saturday, 14th January, 1860, being four weeks "however in all, or 240 hours. Diagrams were taken several engineers, in the discussion, that, perfect weapons might be made, the fate of a times a-day, and the mean accepted as showing battle would never be materially influenced by the actual quantity and force of the steam in the The real struggle would cylinder. M'Naught's indicator was used, and its very distant firing. always lie within a distance of 2,000 yards." He accuracy was occasionally tested both on the further states, according to the published report, boiler and valve casing alongside of Bourdon's "A shot of large diameter, by making a larger pressure gauges, the one in fact checking the achole and producing more splinters and greater curacy of the other. The coal was accurately Heat of feed-water displacement, was in general more efficacious than weighed, and the quantities recorded represent a long narrow bolt." These rifled cast-iron service every pound that was consumed, including the guns will consequently have the same advantage getting up of the steam in the mornings, gatherover the Armstrong medium-sized bore, as the ing the fire at night, and on Sundays. The ashes latter is claimed by the inventor to have over the and clinkers were also carefully weighed. small-bored Whitworth. The larger the shell is the greater of course is its capacity for bursting charge, and there is little doubt about this being of more use than a rather longer range. The bore of the 32-pounder service gun is 63 inches diameter; that of the Armstrong 32-pounder only 4 inches. But there are other positive advantages attaching to the old guns. They are in existence, and are paid for. They are also in the simplest possible form. They are not liable to serious injury from slight blows on external polished surfaces and screw fittings. When exposed in open batteries subject year after year to the effect of a damp and corroding atmosphere, it is most probable that this simplicity will render them far more enduring than the others, because guns are seldom worn out with firing; they become unserviceable in a long course of years from honeycomb and decay.

STEAM ENGINE AND BOILER EXPERI.
MENTS AT THE SCOTLAND-STREET
IRON WORKS, GLASGOW.

By Mr. WILLIAM TAIT,
THREE years ago, the writer commenced a series
of experiments for the purpose of verifying in
some measure the advantages alleged to be de-
rived from the use of high-pressed steam, worked
more or less expansively, as compared with steam
of a lower pressure, worked in the usual way.
Those experiments, however, were soon abandoned,
because the engine was very often worked late,
and occasionally all night, with a load at night
probably not more than one-half of that which
constituted the day's work. It was also found in-
convenient to attend at night to take pressure
diagrams. Similar experiments were again insti-
tuted a few months ago, and although not so com-
plete as were originally intended, they may yet
be interesting to those occupied with similar pur-

suits. The economic conditions under which a

given weight of coal is made to perform a given amount of work, form an important object of inquiry.

The experiments were commenced with steam at a pressure on the safety valve of 55lbs. per square inch, cutting off the steam in the cylinder at one-sixth of the stroke. These experiments were meant to be continued from week to week, and on each succeeding week with four inches more steam in the cylinder, until three-fourths of the stroke was arrived at; but this intention was departed from in consequence of the very irregular and often excessive quantity of coal re

Read at the Institution of Engineers of Scotland.

The evaporation was tested by measuring accurately the surface area of the water in the boiler, and noting its height on the gauge glass before starting the engine at 10 o'clock A.M., and at 2 o'clock P.M., and stopping again at 12 o'clock, and at 5 o'clock P.M., until respectively the fall of the water was ascertained. The engine was stopped for the purpose of letting the water be as quiescent as possible. This again was partially checked by noting the quantity of water taken from a cistern.

Travel of piston before steam is cut off,
nearly...
Indicated horses pwr. (usual method) viz.:
area of cylinder x by effective pressure 35-33
x ft. travelled per min.
33.000

Length of steam-pipe

Diameter of do.

Method of superheating. By 4 copper
pipes through chimney 33 in external
diameter-length 28 ft.- heating surface 26.4 ft.
Temperature of steam in boiler at 44 lbs. 292° Fahr.
Do.
in valve casing at
44 lbs....
291° Fahr.

sure.

The pressure in the boiler and in the casing was indicated by Bourdon's gauges, and showed a nearly absolute uniformity-the greatest variation being from one pound to one and a half pounds; the excess being sometimes in the boiler and sometimes in the casing.

The temperature of the steam in the boiler and valve-casing was tried, for the purpose of ascerThe boiler is represented in the annexed engrav-taining whether any and to what extent heat was ings, Fig. 1 being a sectional plan, and Fig. 2 a imparted to the steam by the copper pipes in the vertical longitudinal section. It is 32 feet 6 inches chimney. In the valve-casing the temperature was 1° lower than in the boiler; the one was 2° long, by 5 feet 2 inches in inside diameter, with and the other 3° below what was due to the prestwo flues passing through it longitudinally, each 18 inches in inside diameter. The fireThis discrepancy was no doubt owing to grate measures 4 feet by feet 3 inches, and currents of cold air, and, at the valve-casing parthe ashpit is fitted with doors. On the centre of ticularly, to the radiation of heat from the surface each door is a fan valve for regulating the admis- of the part where the thermometer was applied. At times, however, the temperatures were uniform sion of air. The wall A at the side of the grate and correct. nearest the chimney is built close up to the boiler. Their are air-holes in this wall, the air being supplied by a valve in front of the building B. This air is of course to aid in abating the smoke nuisance. The furnace bridge rises to within five inches of the boiler, allowing about 510 square inches for the passage of the gases, or about 40 inches per foot of fire-grate. There is no part of the outer shell of the boiler exposed to the action of the fire excepting the part above the furnace, and onwards to where the flame turns upwards to the flue tubes. The recipient surfaces computed by the usual method are equivalent to about 23-horse power. At C, between the boiler and damper, there is another bridge which rises to a level with the centre of the tubes, the opening over it being about 300 square inches. The gases after passing this bridge descend and pass beneath the damper into the chimney. The steampipe to the engine is 49 feet long by 5 inches in diameter, and is carried through the chimney at D, where it is divided into four pipes made of copper, and joined to the iron pipe in the brickwork of the chimney. These pipes possess in all about 26 feet of surface, and may take up a little, a very little of the heat manifestly going to waste up the chimney.

The engine is high-pressure, with cylinder 20 inches in diameter, and a stroke of 4 feet, and it made with great regularity 34 strokes per minute this at any rate being the mean velocity. The cylinder is not jacketed, and has no covering of any kind. The slide-valves are worked by eccentrics both for steam and expansion. Figs. 3 and 4 represent two pairs of top and bottom diagrams taken from the cylinder.

Regarding the quantity of coals consumed, it must be noted that the weather was nearly constantly wet during the experiments; the coals were brought in daily as required, and were weighed often when saturated with water; this water forming, in some instances, a large percentage.

The weather also had an adverse effect on the boiler. The stock of coal in the work was

kept small to prevent the temptation to any excess in firing.

The steam-space in the boiler is noted, because it is large in proportion to the quantity of steam used at a single stroke of the engine; this quantity, including the filling of the steam port, was about 2 cubic feet, which was just about one eighty-third part of the steam in the boiler. This circumstance prevented in a great measure the liability of the water to pass off with the steamwater passing off in that way accounting satisfactorily for the apparently very great success attending many experiments on record; the success being in direct proportion to the amount of priming, or water carried off with the steam. It is doubtful whether or not any material benefit was derived from so partial an attempt at superheating as was tried in the present experiments.

The heat in the flue was high, and, on several occasions, melted zinc; in fact, it was melted on every repetition of the experiment if allowed to