This may be regarded as a fair example of the changes which take place

in the quality of the gas during the distillation of the coal. In

carburetting such a gas by injecting mineral oil into the retort, many

of the products of the decomposition of the oil being vapours, it

would be wasteful to do so for the first two hours, as a rich gas is

being given off which has not the power of carrying in suspension a

much larger quantity of hydrocarbon vapours without being

supersaturated with them. Consequently, to make it carry any further

quantity in a condition not easily deposited, the oil would have to be

completely decomposed into permanent gases, and the temperature

necessary to do this would seriously affect the quality of the gas

given off by the coal. When, however, the distillation has gone on

for three hours, the rich portions of coal have distilled off and the

temperature of the retort has reached its highest point, and this is

the best time to feed in the oil.

Undoubtedly the best process which has been proposed for the

production of oil gas to be used in the enrichment of coal gas is the

"Young" or "Peebles" process, which depends on the principle of

washing the oil gas retorted at a moderate temperature by means of oil

which is afterwards to undergo decomposition, because in this way it

is freed from all condensible vapours, and only permanent gases are

allowed to escape to the purifiers. In the course of this treatment

considerable quantities of the ethylenes and other fixed gases are

also absorbed, but no loss takes place, as these are again driven out

by the heat in the subsequent retorting. The gas obtained by the Young

process, when tested by itself in the burners most suited for its

combustion, gives on the photometer an illuminating value averaging

from 50 to 60 candle-power, but it is claimed, and quite correctly,

that the enriching power of the gas is considerably greater. This is

accounted for by the fact that it is impossible to construct a burner

which will do justice to a gas of such illuminating power.

The fundamental objections to oil gas for the enrichment of coal gas

are, first, that its manufacture is a slow process, requiring as much

plant and space for retorting as coal gas; and, secondly, that

although on a small scale it can be made to mix perfectly with coal

gas and water gas, great difficulties are found in doing this on the

large scale, because in spite of the fact that theoretically gases of

such widely different specific gravities ought to form a perfect

mixture by diffusion, layering of the gas is very apt to take place in

the holder, and thus there is an increased liability to wide

variations in the illuminating value of the gas sent out.

Enrichment by volatile hydrocarbons.

The wonderful carburetting power of benzol vapour is well known, a

large proportion of the total illuminating power of coal gas being due

to the presence of a minute trace of its vapour carried in suspension.

For many years the price of benzol has been falling, owing to the

large quantities produced in the coke ovens, and at its present price

it is by far the cheapest enriching material that can be obtained.

Hence at many gas-works where it is found necessary to do so it is

used in various forms of carburettor, in which it is volatilized and

its vapour used for enriching coal gas up to the requisite

illuminating power.

Enrichment by carburetted water gas.

One of the most generally adopted methods of enrichment now is by

means of carburetted water gas mixed with poor coal gas. When steam

acts upon carbon at a high temperature the resultant action may be

looked upon as giving a mixture of equal volumes of hydrogen and

carbon monoxide, both of which are inflammable but non-luminous gases.

This water gas is then carburetted, i.e. rendered luminous by passing

it through chambers in which oils are decomposed by heat, the mixture

being made so as to give an illuminating value of 22 to 25 candles.

This, mixed with the poor coal gas, brings up its illuminating value

to the required limit. Coke or anthracite is heated to incandescence

by an air blast in a generator lined with fire-brick, and the heated

products of combustion as they leave the generator and enter the

superheaters are supplied with more air, which causes the combustion

of carbon monoxide present in the producer gas and heats up the

fire-brick baffles with which the superheater is filled. When the

necessary temperature of the fuel and superheater has been reached,

the air blast is cut off, and steam is blown through the generator,

forming water gas, which meets the enriching oil at the top of the

first superheater, called the carburettor, and carries the vapours

with it through the main superheaters, where the fixing of the

hydrocarbons takes place. The chief advantage of this apparatus is

that a low temperature can be used for fixing owing to the enormous

surface for superheating, and thus to a great extent the deposition of

carbon is avoided. This form of apparatus has been very generally

adopted in Great Britain as well as in America, and practically all

carburetted water-gas plants are founded upon the same set of actions.

Important factors in the use of carburetted water gas for enrichment

are that it can be made with enormous rapidity and with a minimum of

labour; and not only is the requisite increase in illuminating power

secured, but the volume of the enriched gas is increased by the bulk

of carburetted water gas added, which in ordinary English practice

amounts to from 25 to 50%. The public at first strongly opposed its

introduction on the ground of the poisonous properties of the carbon

monoxide, which is present in it to the extent of about 28 to 30%.

Still when this comes to be diluted with 60 to 75% of ordinary coal

gas, containing as a rule only 4 to 6% of carbon monoxide, the

percentage of poisonous monoxide in the mixture falls to below 16%,

which experience has shown to be a fairly safe limit.

A rise in the price of oil suitable for carburetting has caused the

gas industry to consider other methods by which the volume of gas

obtainable from coal can be increased by admixture with blue or

non-luminous water gas. In Germany, at several important gas-works,

non-luminous water gas is passed into the foul main or through the

retorts in the desired proportion, and the mixture of water gas and

coal gas is then carburetted to the required extent by benzol vapour,

a process which at the present price of oil and benzol is distinctly

more economical than the use of carburetted water gas. In 1896 Karl

Dellwik introduced a modification in the process of making water gas

which entirely altered the whole aspect of the industry. In all the

attempts to make water gas, up to that date, the incandescence of the

fuel had been obtained by "blowing" so deep a bed of fuel that carbon

monoxide and the residual nitrogen of the air formed the chief

products, this mixture being known as "producer" gas. In the Dellwik

process, however, the main point is the adjustment of the air supplied

to the fuel in the generator in such a way that carbon dioxide is

formed instead of carbon monoxide. Under these conditions producer gas

ceases to exist as a by-product, and the gases of the blow consist

merely of the incombustible products of complete combustion, carbon

dioxide and nitrogen, the result being that more than three times the

heat is developed for the combustion of the same amount of fuel, and

nearly double the quantity of water gas can be made per pound of fuel

than was before possible. The runs or times of steaming can also be

continued for longer periods. The possibility of making from 60,000 to

70,000 cub. ft. of water gas per ton of coke used in the Dellwik

generator as against 34,000 to 45,000 cub. ft. per ton made by

previous processes reduces the price of water gas to about 3-1/2d. per

thousand, so that the economic value of using it in admixture with

coal gas and then enriching the mixture by any cheap carburetting

process is manifest. The universal adoption of the incandescent mantle

for lighting purposes has made it evident that the illuminating value

of the gas is a secondary consideration, and the whole tendency now is

to do away with enrichment and produce a gas of low-candle power but

good heating power at a cheap rate for fuel purposes and incandescent

lighting. (See also LIGHTING: _Gas_.) (V. B. L.)

2. _Gas for Fuel and Power_--The first gas-producers, which were built

by Faber du Faur at Wasseralfingen in 1836 and by C.G.C. Bischof at

Magdesprung (both in Germany), consisted of simple perpendicular shafts

of masonry contracted at the top and the bottom, with or without a grate

for the coal. Such producers, frequently strengthened by a wrought iron

casing, are even now used to a great extent. Sometimes the purpose of a

gas-producer is attained in a very simple manner by lowering the grate

of an ordinary fireplace so much that a layer of coal 4 or 5 ft. deep is

maintained in the fire. The effect of this arrangement is that the great

body of coal reaches a higher temperature than in an ordinary fireplace,

and this, together with the reduction of the carbon dioxide formed

immediately above the grate by the red-hot coal in the upper part of the

furnace, leads to the formation of carbon monoxide which later on, on

the spot where the greatest heat is required, is burned into dioxide by

admitting fresh air, preferably pre-heated. This simple and inexpensive

arrangement has the further advantage that the producer-gas is utilized

immediately after its formation, without being allowed to cool down. But

it is not very well adapted to large furnaces, and especially not to

those cases where all the space round the furnace is required for

manipulating heavy, white-hot masses of iron, or for similar purposes.

In these cases the producers are arranged outside the iron-works,

glass-works, &c., in an open yard where all the manipulations of feeding

them with coal, of stoking, and of removing the ashes are performed

without interfering with the work inside. But care must always be taken

to place the producers at such a low level that the gas has an upward

tendency, in order to facilitate its passage to the furnace where it is

to be burned. This purpose can be further promoted by various means. The

gas-producers constructed by Messrs Siemens Brothers, from 1856 onwards,

were provided with a kind of brick chimney; on the top of this there was

a horizontal iron tube, continued into an iron down-draught, and only

from this the underground flues were started which sent the gas into the

single furnaces. This arrangement, by which the gas was cooled down by

the action of the air, acted as a gas-siphon for drawing the gas out of

the producer, but it has various drawbacks and has been abandoned in all

modern constructions. Where the "natural draught" is not sufficient, it

is aided either by blowing air under the grate or else by suction at the

other end.

We shall now describe a few of the very large number of gas-producers

producers constructed, selecting some of the most widely applied in

practice.

[Illustration: FIG. 12[2]--Siemens Producer (Sectional Elevation).]

[Illustration: FIG. 13.--Lurmann's Producer.]

[Illustration: FIGS. 14 and 15.--Liegel's Producer.]

The Siemens Producer in its original shape, of which hundreds have

been erected and many may be still at work, is shown in fig. 12. A is

the charging-hole; B, the inclined front wall, consisting of a cast

iron plate with fire-brick lining; C, the equally inclined

"step-grate"; D, a damper by which the producer may be isolated in

case of repairs; E, a water-pipe, by which the cinders at the bottom

may be quenched before taking away; the steam here formed rises into

the producer where it forms some "semi-water gas" (see FUEL:

_Gaseous_). Openings like that shown at G serve for introducing a

poker in order to clean the brickwork from adhering slags. H is the

gas flue; I, the perpendicularly ascending shaft, 10 or 12 ft. high;

JJ, the horizontal iron tube; K, the descending branch mentioned

above, for producing a certain amount of suction by means of the

gas-siphon thus formed. In the horizontal branch JJ much of the tar

and flue-dust is also condensed, which is of importance where

bituminous coal is employed for firing.

[Illustration: FIG. 16.--Taylor's Producer.]

[Illustration: FIG. 17.--Dowson Gas Plant.]

[Illustration: FIG. 18.--Mond Gas Plant.]

[Illustration: FIG. 19.--Mond Gas Plant.]

This as well as most other descriptions of gas-producers, is not

adapted to being worked with such coal as softens in the heat and

forms cakes, impenetrable to the air and impeding the regular sinking

of the charge in the producer. The fuel employed should be

non-bituminous coal, anthracite or coke, or at least so much of these

materials should be mixed with ordinary coal that no semi-solid cakes

of the kind just described are formed. Where it is unavoidable to work

with coal softening in the fire, Lurmann's producer may be employed,

which is shown in fig. 13. V shows a gas-producer of the ordinary

kind, which during regular work is filled with the coke formed in the

horizontal retort E. The door _b_ serves for removing the slags and

ashes from the bottom of V, as far as they do not fall through the

grate. The hot producer-gas formed in V is passed round the retort E

in the flues n2 n2, and ultimately goes away through K to the furnace

where it is to be used. The retort E is charged with ordinary

bituminous coal which is submitted to destructive distillation by the

heat communicated through the flues n2 n2 and is thus converted into

coke. The gases formed during this process pass into the upper portion

of V and get mixed with the producer-gas formed in the lower portion.

From time to time, as the level of the coke in V goes down, some of

the freshly formed coke in E is pushed into V, whereby the level of

the coke in V should assume the shape shown by the dotted line _l ...

m_. If the level became too low, such as is shown by the dotted line

x ... y, the working of the producer would be wrong, as in this case

the layer of coke at the front side would be too low, and carbon

dioxide would be formed in lieu of monoxide.

[Illustration: FIG. 20.--Blass' Gas Plant.]

Figs. 14 and 15 show Liegel's producer, the special object of which is

to deal with any fuel (coal or coke) giving a tough, pasty slag on

combustion. Such slags act very prejudicially by impeding the

up-draught of the air and the sinking of the fuel; nor can they be

removed by falling through a grate, like ordinary coal-ashes. To

obviate these drawbacks the producer A is kept at a greater heat than

is otherwise usual, the air required for feeding the producer being

pre-heated in the channels e, e. The inside shape of the producer is

such that the upper, less hot portion cannot get stopped, as it widens

out towards the bottom; the lower, hotter portion, where the ashes are

already fluxed, is contracted to a slit a, through which the air

ascends. The grate b retains any small pieces of fuel, but allows the

liquid cinder to pass through. The lateral flues c, c prevent the

brickwork from being melted.

One of the best-known gas-producers for working with compressed air

from below is Taylor's, shown in fig. 16. A is the feeding-hopper, on

the same principle as is used in blast-furnaces. L is the

producer-shaft, with an iron casing B and peep-holes B1 to B4,

passing through the brick lining M. F is the contracted part, leading

to the closed ash-pit, accessible through the doors D. An injector I,

worked by means of the steam-pipe J, forces air through K into F. The

circular grate G can be turned round K by means of the crank E from

the outside. This is done, without interfering with the blast, in

order to keep the fuel at the proper level in L, according to the

indications of the burning zone, as shown through the peep-holes B1 to

B4. The ashes collecting at the bottom are from time to time removed

by the doors D. As the steam, introduced by J, is decomposed in the

producer, we here obtain a "semi-water gas," with about 27% CO and 12%

H2.

Fig. 17 shows the Dowson gas-producer, together with the arrangements

for purifying the gas for the purpose of working a gas engine. _a_ is

a vertical steam boiler, heated by a central shaft filled with coke,

with superheating tubes _b_ passing through the central shaft. _c_ is

the steam-pipe, carrying the dry steam into the air-injector _d_. This

mixture of steam and air enters into the gas-producer _e_ below the

fire-grate _f_. _g_ is the feeding-hopper for the anthracite which is

usually employed in this kind of producer. _h_, _h_ are cooling-pipes

for the gas where most of the undecomposed steam (say 10% of the whole

employed in _d_) is condensed. _i_ is a hydraulic box with water seal;

_j_, a coke-scrubber; _k_, a filter; _l_, a sawdust-scrubber; _m_,

inlet of gas-holder; _n_, gas-holder; _o_, outlet of same; _p_, a

valve with weighted lever to regulate the admission of steam to the

gas-producer; _q_, the weight which actuates the lever automatically

by the rise or fall of the bell of the gas-holder. In practical work

about 3/4 lb. of steam is decomposed for each pound of anthracite

consumed, and no more than 5% of carbon dioxide is found in the

resulting gas. The latter has an average calorific power of 1732

calories per cubic metre, or 161 B.T.U. per cubic foot, at 0 deg. and

760 mm.

The Mond plant is shown in figs. 18 and 19. The gases produced in the

generators G are passed through pipes _r_ into washers W, in which

water is kept in violent motion by means of paddle-wheels. The spray

of water removes the dust and part of the tar and ammonia from the

gases, much steam being produced at the same time. This water is

withdrawn from time to time and worked for the ammonia it contains.

The gases, escaping from W at a temperature of about 100 deg. C., and

containing much steam, pass though _g_ and _a_ into a tower, fed with

an acid-absorbing liquid, coming from the tank _s_, which is spread

into many drops by the brick filling of the tower. This liquid is a

strong solution of ammonium sulphate, containing about 2.5% free

sulphuric acid which absorbs nearly all the ammonia from the gases,

without dissolving much of the tarry substances. Most of the liquor

arriving at the bottom, after mechanically separating the tar, is

pumped back into _s_, but a portion is always withdrawn and worked for

ammonium sulphate. When escaping from the acid tower, the gas contains

about 0.013% NH3, and has a temperature of about 80 deg. C. and is

saturated with aqueous vapour. It is passed through _c_ into a second

tower B, filled with blocks of wood, where it meets with a stream of

comparatively cold water. At the bottom of this the water runs away,

its temperature being 78 deg. C.; at the top the gas passes away

through _d_ into the distributing main. The hot water from B, freed

from tar, is pumped into a third tower C, through which cold air is

forced by means of a Root's blower by the pipe _w_. This air, after

being heated to 76 deg. C., and saturated with steam in the tower C,

passes through _l_ into the generator G. The water in C leaves this

tower cold enough to be used in the scrubber B. Thus two-thirds of the

steam originally employed in the generator is reintroduced into it,

leaving only one-third to be supplied by the exhaust steam of the

steam-engine. The gas-generators G have a rectangular section, 6 X 12

ft., several of them being erected in series. The introduction of the

air and the removal of the ashes takes place at the narrower ends. The

bottom is formed by a water-tank and the ashes are quenched here. The

air enters just above the water-level, at a pressure of 4 in. The

Mond gas in the dry state contains 15% carbon dioxide, 10% monoxide,

23% hydrogen, 3% hydrocarbons, 49% nitrogen. The yield of ammonium

sulphate is 75 lb. from a ton of coal (slack with 11.5% ashes and 55%

fixed carbon).

One of the best plants for the generation of _water-gas_ is that

constructed by E. Blass (fig. 20). Steam enters through the valve V at

D into the generator, filled with coke, and passes away at the bottom

through A. The pressure of the gas should not be such that it could

get into the pipe conveying the air-blast, by which an explosive

mixture would be formed. This is prevented by the water-cooled damper

S, which always closes the air-blast when the gas-pipe is open and

vice versa. Below the entry W of the air-blast there is a throttle

valve _d_ which is closed as soon as the damper S opens the gas canal;

thus a second security against the production of a mixture of air and

gas is afforded. The water-cooled ring channel K protects the bottom

outlet of the generator and causes the cinders to solidify, so that

they can be easily removed. But sometimes no such cooling is effected,

in which case the cinders run away in the liquid form. Below K the

fuel is lying in a conical heap, leaving the ring channel A free.

During the period of hot-blowing (heating-up) S is turned so that the

air-blast communicates with the generator; _d_ and G are open; _g_

(the damper connected with the scrubber) and V are closed. During the

period of gas-making G and _d_ are closed, S now closes the air-blast

and connects the generator with the scrubber; V is opened, and the gas

passes from the scrubber into the gas-holder, the inlet w being under

a pressure of 4 in. All these various changes in the opening of the

valves and dampers are automatically performed in the proper order by

means of a hand-wheel H, the shaft m resting on the standards t and

shaft _v_. This hand-wheel has merely to be turned one way for

starting the hot-blowing, and the opposite way for gas-making, to open

and shut all the connexions, without any mistake being possible on the

part of the attendant. The feeding-hopper E is so arranged that, when

the cone e2 opens, e1 is shut, and vice versa, thus no more gas can

escape, on feeding fresh coke into the generator, than that which is

contained in E. G is the pipe through which the blowing-up gas

(Siemens gas) is carried away, either into the open air (where it is

at once burned) or into a pre-heater for the blast, or into some place

where it can be utilized as fuel. This gas, which is made for 10 or 11

minutes, contains from 23 to 32% carbon monoxide, 7 to 1.5% carbon

dioxide, 2 to 3% hydrogen, a little methane, 64 to 66% nitrogen, and

has a heating value of 950 calories per cub. metre. The water-gas

itself is made for 7 minutes, and has an average composition of 3.3%

carbon dioxide, 44% carbon monoxide, 0.4% methane, 48.6% hydrogen,

3.7% nitrogen, and a heating value of 2970 calories per cub. metre. 1

kilogram coke yields 1.13 cub. metre water-gas and 3.13 Siemens gas.

100 parts coke (of 7000 calories) furnish 42% of their heat value as

water-gas and 42% as Siemens gas.

[Illustration: FIG. 21.--Dellwik-Fleischer Producer.]

Lastly we give a section of the Dellwik-Fleischer gas-producer (fig.

21). The feeding-hoppers A are alternately charged every half-hour, so

that the layer of fuel in the generator always remains 4 ft. deep. B

is the chimney-damper, C the grate, D the door for removing the slags,

E the ash-door, F the inlet of the air-blast, G the upper, G1 the

lower outlet for the water-gas which is removed alternately at top and

bottom by means of an outside valve, steam being always admitted at

the opposite end. The blowing-up generally lasts 1-3/4 minutes, the

gas-making 8 or 10 minutes. The air-blast works under a pressure of 8

or 9 in. below the grate, or 4 to 4-1/2 in. above the coke. The

blowing-up gas contains 17 or 18% carbon dioxide and 1.5% oxygen, with

mere traces of carbon monoxide. The water-gas shows 4 to 5% carbon

dioxide, 40% carbon monoxide, 0.8% methane, 48 to 51% hydrogen, 4 or

5% nitrogen. About 2.5 cub. metres is obtained per kilogram of best

coke.

See Mills and Rowan, _Fuel and its Application_ (London, 1889); Samuel

S. Wyer, _Producer-Gas and Gas-Producers_, published by the

_Engineering and Mining Journal_ (New York); F. Fischer, _Chemische

Technologie der Brennstoffe_ (1897-1901); _Gasformige Heizstoffe_, in

Stohmann and Kerl's _Handbuch der technischen Chemie_, 4th edition,

iii. 642 et seq. (G. L.)

FOOTNOTES:

[1] Liquor condensed from gas alone, without wash water.

[2] Figs. 12, 13, 14, 15, 16, 18, 19, 20, 21 of this article are from

Lunge's _Coal-tar and Ammonia_, by permission of Friedr. Vieweg u.

Sohn.

GASCOIGNE, GEORGE (c. 1535-1577), English poet, eldest son of Sir John

Gascoigne of Cardington, Bedfordshire, was born probably between 1530

and 1535. He was educated at Trinity College, Cambridge, and on leaving

the university is supposed to have joined the Middle Temple. He became

a member of Gray's Inn in 1555. He has been identified without much show

of evidence with a lawyer named Gastone who was in prison in 1548 under

very discreditable circumstances. There is no doubt that his escapades

were notorious, and that he was imprisoned for debt. George Whetstone

says that Sir John Gascoigne disinherited his son on account of his

follies, but by his own account he was obliged to sell his patrimony to

pay the debts contracted at court. He was M.P. for Bedford in 1557-1558

and 1558-1559, but when he presented himself in 1572 for election at

Midhurst he was refused on the charges of being "a defamed person and

noted for manslaughter," "a common Rymer and a deviser of slaunderous

Pasquelles," "a notorious ruffianne," an atheist and constantly in debt.

His poems, with the exception of some commendatory verses, were not

published before 1572, but they were probably circulated in MS. before

that date. He tells us that his friends at Gray's Inn importuned him to

write on Latin themes set by them, and there two of his plays were

acted. He repaired his fortunes by marrying the wealthy widow of William

Breton, thus becoming step-father to the poet, Nicholas Breton. In 1568

an inquiry into the disposition of William Breton's property with a view

to the protection of the children's rights was instituted before the

lord mayor, but the matter was probably settled in a friendly manner,

for Gascoigne continued to hold the Walthamstow estate, which he had

from his wife, until his death. He sailed as a soldier of fortune to the

Low Countries in 1572, and was driven by stress of weather to Brill,

which luckily for him had just fallen into the hands of the Dutch. He

obtained a captain's commission, and took an active part in the

campaigns of the next two years, during which he acquired a profound

dislike of the Dutch, and a great admiration for William of Orange, who

had personally intervened on his behalf in a quarrel with his colonel,

and secured him against the suspicion caused by his clandestine visits

to a lady at the Hague. Taken prisoner after the evacuation of

Valkenburg by the English troops, he was sent to England in the autumn

of 1574. He dedicated to Lord Grey of Wilton the story of his

adventures, "The Fruites of Warres" (printed in the edition of 1575) and

"Gascoigne's Voyage into Hollande." In 1575 he had a share in devising

the masques, published in the next year as _The Princely Pleasures at

the Courte at Kenelworth_, which celebrated the queen's visit to the

Earl of Leicester. At Woodstock in 1575 he delivered a prose speech

before Elizabeth, and presented her with the _Pleasant Tale of Hemetes

the Heremite_[1] in four languages. Most of his works were actually

published during the last years of his life, after his return from the

wars. He died at Bernack, near Stamford, where he was the guest of

George Whetstone, on the 7th of October 1577. George Whetstone wrote a

long dull poem in honour of his friend, entitled "A Remembrance of the

wel-imployed life and godly end of George Gaskoigne, Esquire."

His theory of metrical composition is explained in a short critical

treatise, "Certayne Notes of Instruction concerning the making of verse

or ryme in English, written at the request of Master Edouardo

Donati,"[2] prefixed to his _Posies_ (1575). He acknowledged Chaucer as

his master, and differed from the earlier poets of the school of Surrey

and Wyatt chiefly in the added smoothness and sweetness of his verse.

His poems were published in 1572 during his absence in Holland,

surreptitiously, according to his own account, but it seems probable

that the "editor" who supplied the running comment was none other than

Gascoigne himself. _A hundreth Sundrie Floures bound up in one small

Posie. Gathered partely (by translation) in the fyne outlandish Gardens

of Euripides, Ovid, Petrarke, Ariosto and others; and partely by

Invention out of our owne fruitfull Orchardes in Englande, Yelding

Sundrie Savours of tragical, comical and moral discourse, bothe

pleasaunt and profitable, to the well-smelling noses of learned

Readers_, was followed in 1575 by an authorized edition, _The Posies of

G.G. Esquire_ ... (not dated).

Gascoigne had an adventurous and original mind, and was a pioneer in

more than one direction. In 1576 he published _The Steele Glas_,

sometimes called the earliest regular English satire. Although this poem

is Elizabethan in form and manner, it is written in the spirit of _Piers

Plowman_. Gascoigne begins with a comparison between the sister arts of

Satire and Poetry, and under a comparison between the old-fashioned

"glas of trustie steele," and the new-fangled crystal mirrors which he

takes as a symbol of the "Italianate" corruption of the time, he attacks

the amusements of the governing classes, the evils of absentee

landlordism, the corruption of the clergy, and pleads for the

restoration of the feudal ideal.[3]

His dramatic work belongs to the period of his residence at Gray's Inn,

both _Jocasta_ (of which Acts i. and iv. were contributed by Francis

Kinwelmersh) and _Supposes_ being played there in 1566. _Jocasta_ was

said by J.P. Collier (_Hist. of Dram. Poetry_ iii. 8) to be the "first

known attempt to introduce a Greek play upon the English stage," but it

turns out that Gascoigne was only very indirectly acquainted with

Euripides. His play is a literal version of Lodovico Dolce's _Giocasta_,

which was derived probably from the _Phoenissae_ in the Latin

translation of R. Winter. _Supposes_,[4] a version of Ariosto's _I

Suppositi_, is notable as an early and excellent adaptation of Italian

comedy, and moreover, as "the earliest play in English prose acted in

public or private." Udal's _Ralph Roister Doister_ had been inspired

directly by Latin comedy; _Gammer Gurton's Needle_ was a purely native

product; but _Supposes_ is the first example of the acclimatization of

the Italian models that were to exercise so prolonged an influence on

the English stage. A third play of Gascoigne's, _The Glasse of

Government_ (published in 1575), is a school drama of the "Prodigal Son"

type, familiar on the continent at the time, but rare in England. It is

defined by Mr C.H. Herford as an attempt "to connect _Terentian

situation_ with a _Christian moral_ in a picture of _school life_," and

it may be assumed that Gascoigne was familiar with the didactic drama of

university life in vogue on the continent. The scene is laid at Antwerp,

and the two prodigals meet with retribution in Geneva and Heidelberg

respectively.

_The Spoyle of Antwerpe_, written by an eyewitness of the sack of the

city in 1576, has sometimes been attributed to Gascoigne, but although a

George Gascoigne was employed in that year to carry letters for

Walsingham, internal evidence is against Gascoigne's authorship. A

curious editorial preface by Gascoigne to Sir Humphrey Gilbert's

_Discourse of a Discoverie for a new Passage to Cataia_ (1576) has led

to the assertion that Gascoigne printed the tract against its author's

wish, but it is likely that he was really serving Gilbert, who desired

the publication, but dared not avow it. The _Wyll of the Devill_ ...

(reprinted for private circulation by Dr F.J. Furnivall, 1871), an

anti-popish tract, once attributed, on slender evidence, to Gascoigne,

is almost certainly by another hand.

Gascoigne's works not already mentioned include: "G. G. in

commendation of the noble Arte of Venerie," prefixed to _The Noble Art

of Venerie or Hunting_ (1575); _The Complaynte of Phylomene, bound up

with The Steele Glas_ (1576); _The Droomme of Doomes-day_ (1576), a

prose compilation from various authors, especially from the _De

contemptu mundi sive de miseria humanae conditionis_ of Pope Innocent

III., printed with varying titles, earliest ed. (1470?); _A Delicate

Diet for daintie mouthde droonkardes ..._ (1576), a free version of St

Augustine's _De ebrietate_. _The Posies_ (1572) included _Supposes_,

_Jocasta_, _A Discourse of the Adventures of Master F[erdinando]

J[eronimi]_, in imitation of an Italian novella, a partly

autobiographical _Don Bartholomew of Bath_, and miscellaneous poems.

Real personages, some of whom were well known at court, were supposed

to be concealed under fictitious names in _The Adventures of Master F.

J._, and the poem caused considerable scandal, so that the names are

disguised in the second edition. A more comprehensive collection, _The

Whole Workes of G. G._ ... appeared in 1587. In 1868-1870 _The

Complete Poems of G. G._ ... were edited for the Roxburghe Library by

Mr W.C. Hazlitt. In his _English Reprints_ Prof. E. Arber included

_Certayne Notes of Instruction, The Steele Glas_ and the _Complaynt of

Philomene_. _The Steele Glas_ was also edited for the _Library of

English Literature_, by Henry Morley, vol. i. p. 184 (1889). A new

edition, _The Works of George Gascoigne_ (The Cambridge English

Classics, 1907, &c.) is edited by Dr J.W. Cunliffe. See also _The Life

and Writings of George Gascoigne_, by Prof. Felix E. Schelling

(Publications of the Univ. of Pennsylvania series in Philology, vol.

ii. No. 4 [1894]); C.H. Herford, _Studies in the Literary Relations of

England and Germany in the Sixteenth Century_, pp. 149-164 (1886);

C.H. Herford, "Gascoigne's Glasse of Government," in _Englische

Studien_, vol. ix. (Halle, 1877, &c.).

FOOTNOTES:

[1] Printed in 1579 in a pamphlet called _The Paradoxe_, the author

of which, Abraham Fleming, does not mention Gascoigne's name.

[2] Reprinted in vol. ii. of J. Haslewood's _Ancient Critical Essays_

(1811-1815), and in Gregory Smith's _Elizabethan Critical Essays_

(1904).

[3] "Againe I see, within my glasse of Steele

But foure estates, to serve each country soyle,

The King, the Knight, the Pesant, and the Priest.

The King should care for al the subjects still,

The Knight should fight, for to defend the same,

The Pesant, he shoulde labor for their ease,

And Priests shuld pray, for them and for themselves."--

(Arber's ed. p. 57.)

[4] The influence of this play on the Shakespearian _Taming of the

Shrew_ is dealt with by Prof. A.H. Tolman in _Shakespeare's Part in

the Taming of the Shrew_ (Pub. of the Mod. Lang. Assoc. vol. v. No.

4, pp. 215, 216, 1890).

GASCOIGNE, SIR WILLIAM (c. 1350-1419), chief justice of England in the

reign of Henry IV. Both history and tradition testify to the fact that

he was one of the great lawyers who in times of doubt and danger have

asserted the principle that the head of the state is subject to law, and

that the traditional practice of public officers, or the expressed voice

of the nation in parliament, and not the will of the monarch or any part

of the legislature, must guide the tribunals of the country. He was a

descendant of an ancient Yorkshire family. The date of his birth is

uncertain, but it appears from the year-books that he practised as an

advocate in the reigns of Edward III. and Richard II. On the banishment

of Henry of Lancaster Gascoigne was appointed one of his attorneys, and

soon after Henry's accession to the throne was made chief justice of the

court of king's bench. After the suppression of the rising in the north

in 1405, Henry eagerly pressed the chief justice to pronounce sentence

upon Scrope, the archbishop of York, and the earl marshal Thomas

Mowbray, who had been implicated in the revolt. This he absolutely

refused to do, asserting the right of the prisoners to be tried by their

peers. Although both were afterwards executed, the chief justice had no

part in the transaction. It has been very much doubted, however, whether

Gascoigne could have displayed such independence of action without

prompt punishment or removal from office following. The oft-told tale of

his committing the prince of Wales to prison must also be regarded as

unauthentic, though it is both picturesque and characteristic. The judge

had directed the punishment of one of the prince's riotous companions,

and the prince, who was present and enraged at the sentence, struck or

grossly insulted the judge. Gascoigne immediately committed him to

prison, using firm and forcible language, which brought him to a more

reasonable mood, and secured his voluntary obedience to the sentence.

The king is said to have approved of the act, but there appears to be

good ground for the supposition that Gascoigne was removed from his post

or resigned soon after the accession of Henry V. He died in 1419, and

was buried in the parish church of Harewood in Yorkshire. Some

biographies of the judge have stated that he died in 1412, but this is

clearly disproved by Foss in his _Lives of the Judges_; and although it

is clear that Gascoigne did not hold office long under Henry V., it is

not absolutely impossible that the scene in the fifth act of the second

part of Shakespeare's _Henry IV._ has some historical basis, and that

the judge's resignation was voluntary.

GASCONY (_Wasconia_), an old province in the S.W. of France. It takes

its name from the Vascones, a Spanish tribe which in 580 and 587 crossed

the Pyrenees and invaded the district known to the Romans as

Novempopulana or Aquitania tertia. Basque, the national language of the

Vascones, took root only in a few of the high valleys of the Pyrenees,

such as Soule and Labourd; in the plains Latin dialects prevailed,

Gascon being a Romance language. In the 7th century the name of Vasconia

was substituted for that of Novempopulana. The Vascones readily

recognized the sovereignty of the Merovingian kings. In 602 they

consented to be governed by a duke called Genialis, but in reality they

remained independent. They even appointed national dukes, against whom

Charlemagne had to fight at the beginning of his reign. Finally Duke

Lupus II. made his submission in 819, and the Carolingians were able to

establish Frankish dukes in the country. Three of these are known:

Seguin (Sighivinus), William (Guillaume), and Arnaud (Arnaldus). They

were at the same time counts of Bordeaux, and succumbed to the Normans.

After the death of Arnaud in 864 the history of Gascony falls into the

profoundest obscurity. The lists of the 10th-century dukes prepared by

ancient and modern historians can only be established by means of

hypotheses based in many cases on spurious documents (e.g. the charter

of Alaon), and little confidence can be placed in them. During this

troubled period Gascony was from time to time attached to one or other

of the other Vascon states which had been formed on the southern slope

of the Pyrenees, but in the reign of Hugh Capet it was considered as

forming part of France, from which it has never been separated. Disputed

in the 11th century by the counts of Poitiers, who were also dukes of

Aquitaine, and by the counts of Armagnac, the duchy finally passed to

the house of Poitiers in 1073, when the title of duke of Gascony was

merged in that of duke of Aquitaine and disappeared. In the feudal

period Gascony comprised a great number of countships (including

Armagnac, Bigorre, Fezensac, Gaure and Pardiac), viscountships

(including Bearn, Lomagne, Dax, Juliac, Soule, Marsan, Tartas, Labourd

and Maremne), and seigneuries (e.g. Albret, &c.). From the

ecclesiastical point of view, it corresponded nearly to the

archbishopric of Auch.

From about 1073 to 1137 Gascony was governed by the dukes of Aquitaine

and counts of Poitiers, one of whom, William IX., gave the first charter

of privileges to the town of Bayonne; but the duchy was weakened by the

increasing independence of its great feudatories, especially the

viscounts of Bearn and the counts of Armagnac. In 1137, the year of her

father's death, Eleanor, the daughter and heiress of Duke William X.,

married the king of France, Louis VII., and with the rest of Aquitaine

Gascony passed under his direct rule. In 1151, however, this marriage

was annulled, and almost at once Eleanor married Henry of Anjou, who

three years later became king of England as Henry II. Thus was the house

of Plantagenet introduced into Gascony and a fresh bone of contention

was thrown between the kings of England and of France. Having

established himself in the duchy by force of arms, Henry handed it over

to his son Richard, against whom many of the great Gascon lords

revolted, and from Richard it passed to his brother John. The crusade

against the Albigenses was carried into Gascony, and this warfare gave a

new impetus to the process of disintegration which was already at work

in the duchy. King John and his successor Henry III. were weak; the

neighbouring counts of Toulouse were powerful and aggressive; and the

house of Bearn was growing in strength. Gascony served Henry III. as

headquarters during his two short and disastrous wars (1230 and 1242)

with Louis IX., and in 1259 he did homage for it to this king; his son,

Edward I., lost and then regained the duchy.

During the Hundred Years' War Gascony was obviously a battle-field for

the forces of England and of France. The French seized the duchy, but,

aided by the rivalry between the powerful houses of Foix and Armagnac,

Edward III. was able to recover it, and by the treaty of Bretigny in

1360 John II. recognized the absolute sovereignty of England therein.

Handed over as a principality by Edward to his son, the Black Prince, it

was used by its new ruler as a base during his expedition into Spain, in

which he received substantial help from the Gascon nobles. The renewal

of the war between England and France, which took place in 1369, was due

in part to a dispute over the sovereignty of Gascony, and during its

course the position of the English was seriously weakened, the whole of

the duchy save a few towns and fortresses being lost; but the victories

of Henry V. in northern France postponed for a time the total expulsion

of the foreigner. This was reserved for the final stage of the war and

was one result of the efforts of Joan of Arc, the year 1451 witnessing

the capture of Bayonne and the final retreat of the English troops from

the duchy. During this time the inhabitants of Gascony suffered severely

from the ravages of both parties, and the nobles ruled or misruled

without restraint.

The French kings, especially Louis XI., managed to restore the royal

authority in the duchy, although this was not really accomplished until

the close of the 15th century when the house of Armagnac was overthrown.

It was by means of administrative measures that these kings attained

their object. Gascony was governed on the same lines as other parts of

France and from the time of Henry IV., who was prince of Bearn, and who

united his hereditary lands with the crown, its history differs very

slightly from that of the rest of the country. The Renaissance inspired

the foundation of educational institutions and the Reformation was

largely accepted in Bearn, but not in other parts of Gascony. The wars

of religion swept over the land, which was the scene of some of the

military exploits of Henry IV., and Louis XIV. made some slight changes

in its government. As may be surmised the boundaries of Gascony varied

from time to time, but just before the outbreak of the Revolution they

were the Atlantic Ocean, Guienne, Languedoc and the Pyrenees, and from

east to west the duchy at its greatest extent measured 170 m.

At the end of the _ancien regime_ Gascony was united with Guienne to

form a great military government. After the division of France into

departments, Gascony, together with Bearn, French Navarre and the Basque

country, formed the departments of Basses-Pyrenees, Landes,

Hautes-Pyrenees and Gers. Parts of Gascony also now form arrondissements

and cantons of the departments of Lot-et-Garonne, Haute-Garonne, Ariege

and Tarn-et-Garonne.

See Arnaud Oihenart, _Notitia utriusque Vasconiae, tam Ibericae quam

Aquitanicae_ (1637); L'Abbe Monlezun, _Histoire de la Gascogne_

(1846-1850), comprising a number of useful but uncritically edited

documents; and Jean de Jaurgain, _La Vasconie, etude historique et

critique sur les origines ... du duche de Gascogne ... et des grands

fiefs du duche de Gascogne_ (1898-1902), a learned and ingenious work,

but characterized by unbridled genealogical fancy. This last work was

rectified by Ferdinand Lot in his _Etudes sur le regne de Hugues

Capet_ (1903; see especially appendix x.). See also Barrau-Dihigo, "La

Gascogne," a bibliography of manuscript sources and of printed works

published in the _Revue de synthese historique_ (1903). (C. B.*)

GAS ENGINE. A gas engine is a heat engine in which the working fluid is

atmospheric air and the fuel an inflammable gas. It differs from a

hot-air or a steam engine in that the heat is given to the working fluid

by combustion within the motive power cylinder. In most gas engines--in

fact, in all those at present on the market--the working fluid and the

fuel that supplies it with heat are mixed with each other before the

combustion of the fuel. The fuel--which in the steam and in most hot-air

engines is burned in a separate furnace--is, in the gas engine,

introduced directly to the motor cylinder and burned there; it is,

indeed, part of the working fluid. A gas engine, therefore, is an

internal combustion engine using gaseous fuel.

The commercial history of the gas engine dates from 1876, when Dr N.A.

Otto patented the well-known engine now in extensive use, but long

before that year inventors had been at work, attempting to utilize gas

for producing motive power. The first proposal made in Great Britain

is found in Street's Patent No. 1983 of 1794, where an explosion

engine is suggested, the explosion to be caused by vaporizing spirits

of turpentine on a heated metal surface, mixing the vapour with air in

a cylinder, firing the mixture, and driving a piston by the explosion

produced. Most of the early engines were suggested by the fact that a

mixture of an inflammable gas and atmospheric air gives an explosion

when ignited--that is, produces pressure which can be applied in a

cylinder to propel a piston. Lebon, in France, proposed a gas engine

in which the gas and air were raised to a pressure above that of the

atmosphere before use in the cylinder, but he did not appear to be

clear in his ideas.

Some interesting particulars of early experiments are given in a paper

read at the Cambridge Philosophical Society in 1820 entitled, "On the

Application of Hydrogen Gas to produce a Moving Power in Machinery,

with a description of an Engine which is moved by the pressure of the

Atmosphere upon a Vacuum caused by Explosions of Hydrogen Gas and

Atmospheric Air." In that paper the Rev. W. Cecil describes an engine

of his invention constructed to operate on the explosion vacuum

method. This engine was stated to run with perfect regularity at 60

revolutions per minute, consuming 17.6 cub. ft. of hydrogen gas per

hour. The hydrogen explosion, however, does not seem to have been

noiseless, because Mr Cecil states that in building a larger engine

"... to remedy the noise which is occasioned by the explosion, the

lower end of the cylinder A, B, C, D may be buried in a well or it may

be enclosed in a large air-tight vessel." Mr Cecil also mentions

previous experiments at Cambridge by Prof. Farish, who exhibited at

his lectures on mechanics an engine actuated by the explosion of a

mixture of gas and air within a cylinder, the explosion taking place

from atmospheric pressure. Prof. Farish is also stated to have

operated an engine by gunpowder. These engines of Farish and Cecil

appear to be the very earliest in actual operation in the world.

Samuel Brown, in patents dated 1823 and 1826, proposed to fill a

closed chamber with a gas flame, and so expel the air; then he

condensed the flame by injecting water, and operated an air engine by

exhausting into the partial vacuum so obtained. The idea was evidently

suggested by Watt's condensing steam engine, flame being employed

instead of steam to obtain a vacuum. Brown's engine is said to have

been actually employed to pump water, drive a boat on the Thames, and

propel a road carriage. L.W. Wright in 1833 described an explosion

engine working at atmospheric pressure and exploding on both sides of

the piston. The cylinder is shown as water-jacketed. In William

Barnett's engine of 1838 two great advances were made. The engine was

so constructed that the mixture of gas and air was compressed to a

considerable extent in the motor cylinder before ignition. The method

of igniting the compressed charge was also effective. The problem of

transferring a flame to the interior of a cylinder when the pressure

is much in excess of that of the external air was solved by means of a

hollow plug cock having a gas jet burning within the hollow. In one

position the hollow was opened to the atmosphere, and a gas jet

issuing within it was lit by an external flame, so that it burned

within the hollow. The plug was then quickly rotated, so that it

closed to the external air and opened to the engine cylinder; the

flame continued to burn with the air contained in the cock, until the

compressed inflammable mixture rushed into the space from the cylinder

and ignited at the flame. This mode of ignition is in essentials the

one adopted by Otto about thirty years later. To Barnett belongs the

credit of being the first to realize clearly the great idea of

compression before explosion in gas engines, and to show one way of

carrying out the idea in practice. Barnett appears to have constructed

an engine, but he attained no commercial success. Several attempts to

produce gas engines were made between 1838 and 1860, but they were all

failures. Several valuable ideas were published in 1855. Drake, an

American, described a mode of igniting a combustible gaseous mixture

by raising a thimble-shaped piece of metal to incandescence. In 1857

Barsanti and Matteucci proposed a free-piston engine, in which the

explosion propelled a free piston against the atmosphere, and the work

was done on the return stroke by the atmospheric pressure, a partial

vacuum being produced under the piston. The engine never came into

commercial use, although the fundamental idea was good.

Previous to 1860 the gas engine was entirely in the experimental

stage, and in spite of many attempts no practical success was

attained. E. Lenoir, whose patent is dated 1860, was the inventor of

the first gas engine that was brought into general use. The piston,

moving forward for a portion of its stroke by the energy stored in the

fly-wheel, drew into the cylinder a charge of gas and air at the

ordinary atmospheric pressure. At about half stroke the valves closed,

and an explosion, caused by an electric spark, propelled the piston to

the end of its stroke. On the return stroke the burnt gases were

discharged, just as a steam engine exhausts. These operations were

repeated on both sides of the piston, and the engine was thus

double-acting. Four hundred of these engines were said to be at work

in Paris in 1865, and the Reading Iron Works Company Limited built and

sold one hundred of them in Great Britain. They were quiet, and smooth

in running; the gas consumption, however, was excessive, amounting to

about 100 cub. ft. per indicated horse-power per hour. The electrical

ignition also gave trouble. Hugon improved on the engine in 1865 by

the introduction of a flame ignition, but no real commercial success

was attained till 1867, when Otto and Langen exhibited their

free-piston engine in the Paris Exhibition of that year. This engine

was identical in principle with the Barsanti and Matteucci, but Otto

succeeded where those inventors failed. He worked out the engine in a

very perfect manner, used flame ignition, and designed a practical

clutch, which allowed the piston free movement in one direction but

engaged with the fly-wheel shaft when moved in the other; it consisted

of rollers and wedge-shaped pockets--the same clutch, in fact, as has

since been so much used in free-wheel bicycles. This engine consumed

about 40 cub. ft. of gas per brake horse-power per hour--less than

half as much as the Lenoir. Several thousands were made and sold, but

its strange appearance and unmechanical operation raised many

objections. Several inventors meanwhile again advocated compression of

the gaseous mixture before ignition, among them being Schmidt, a

German, and Million, a Frenchman, both in 1861.

To a Frenchman, Alph. Beau de Rochas, belongs the credit of proposing,

with perfect clearness, the cycle of operations now widely used in

compression gas engines. In a pamphlet published in Paris in 1862, he

stated that to obtain economy with an explosion engine four conditions

are requisite: (1) The greatest possible cylinder volume with the

least possible cooling surface; (2) the greatest possible rapidity of

explosion; (3) the greatest possible expansion; and (4) the greatest

possible pressure at the beginning of the expansion. The sole

arrangement capable of satisfying these conditions he stated would be

found in an engine operating as follows: (1) Suction during an entire

out-stroke of the piston; (2) compression during the following

in-stroke; (3) ignition at the dead point, and expansion during the

third stroke; (4) forcing out of the burnt gases from the cylinder on

the fourth and last return stroke. Beau de Rochas thus exactly

contemplated, in theory at least, the engine produced by Dr Otto

fourteen years later. He did not, however, put his engine into

practice, and probably had no idea of the practical difficulties to be

overcome before realizing his conception in iron and steel. To Dr Otto

belongs the honour of independently inventing the same cycle, now

correctly known as the Otto cycle, and at the same time overcoming all

practical difficulties and making the gas engine of world-wide

application. This he did in 1876, and his type of engine very rapidly

surpassed all others, so that now the Otto-cycle engine is

manufactured over the whole world by hundreds of makers. In 1876 Dr

Otto used low compression, only about 30 lb. per sq. in. above

atmosphere. Year by year compression was increased and greater power

and economy were obtained, and at present compressions of more than

100 lb. per sq. in. are commonly used with most satisfactory results.

The history of the subject since 1876 is one of gradual improvement in

detail of construction, enabling higher compressions to be used with

safety, and of gradual but accelerating increase in dimensions and

power. In the same period light and heavy oil engines have been

developed, mostly using the Otto cycle (see OIL ENGINE).

Gas engines may be divided, so far as concerns their working process,

into three well-defined types:--

(1) Engines igniting at constant volume, but without previous

compression.

(2) Engines igniting at constant pressure, with previous compression.

(3) Engines igniting at constant volume, with previous compression.

For practical purposes engines of the first type may be disregarded. Gas

engines without compression are now considered to be much too wasteful

of gas to be of commercial importance. Those of the second type have

never reached the stage of extended commercial application; they are

scientifically interesting, however, and may take an important place in

the future development of the gas engine. The expectations of Sir

William Siemens with regard to them have not been realized, although he

spent many years in experiments. Of other engineers who also devoted

much thought and work to this second type may be mentioned Brayton

(1872); Foulis (1878); Crowe (1883); Hargreaves (1888); Clerk (1889);

and Diesel (1892). Diesel's engines are proving successful as oil

engines but have not been introduced as gas engines.

The working cycles of the three types are as follows:--

_First Type._--Four operations.

(a) Charging the cylinder with explosive mixture at atmospheric

pressure.

(b) Exploding the charge.

(c) Expanding after explosion.

(d) Expelling the burnt gases.

_Second Type._--Five operations.

(a) Charging the pump cylinder with gas and air mixture at

atmospheric pressure.

(b) Compressing the charge into an intermediate receiver.

(c) Admitting the charge to the motor cylinder, in a state of

flame, at the pressure of compression.

(d) Expanding after admission.

(e) Expelling the burnt gases.

_Third Type._--Five operations.

(a) Charging the cylinder with gas and air mixture at atmospheric

pressure.

(b) Compressing the charge into a combustion space.

(c) Exploding the charge.

(d) Expanding after explosion.

(e) Expelling the burnt gases.

In all these types the heating of the working fluid is accomplished by

the rapid method of combustion within the cylinder, and for the

cooling necessary in all heat engines is substituted the complete

rejection of the working fluid with the heat it contains, and its

replacement by a fresh portion taken from the atmosphere at

atmospheric temperature. This is the reason why those cycles can be

repeated with almost indefinite rapidity, while the old hot-air

engines had to run slowly in order to give time for the working fluid

to heat or cool through metal surfaces.

[Illustration: FIG. 1.--Side Elevation of Otto Cycle Engine.]

_Four-cycle Engines._--Otto-cycle engines belong to the third type,

being explosion engines in which the combustible mixture is compressed

previous to explosion. Fig. 1 is a side elevation, fig. 2 is a sectional

plan, and fig. 3 is an end elevation of an engine built about 1892 by

Messrs Crossley of Manchester, who were the original makers of Otto

engines in Great Britain. In external appearance it somewhat resembles a

modern high-pressure steam engine, of which the working parts are

exceedingly strong. In its motor and only cylinder, which is horizontal

and open-ended, works a long trunk piston, the front end of which

carries the crosshead pin. The crank shaft is heavy, and the fly-wheel

large, considerable stored energy being required to carry the piston

through the negative part of the cycle. The cylinder is considerably

longer than the stroke, so that the piston when full in leaves a space

into which it does not enter. This is the combustion space, in which the

charge is first compressed and then burned. On the forward stroke, the

piston A (fig. 2) takes into the cylinder a charge of mixed gas and air

at atmospheric pressure, which is compressed by a backward stroke into

the space Z at the end of the cylinder. The compressed charge is then

ignited, and so the charge is exploded with the production of a high

pressure. The piston now makes a forward stroke under the pressure of

the explosion, and on its return, after the exhaust valve is opened,

discharges the products of combustion. The engine is then ready to go

through the same cycle of operations. It thus takes four strokes or two

revolutions of the shaft to complete the Otto cycle, the cylinder being

used alternately as a pump and a motor, and the engine, when working at

full load, thus gives one impulse for every two revolutions. The valves,

which are all of the conical-seated lift type, are four in

number--charge inlet valve, gas inlet valve, igniting valve, and exhaust

valve. The igniting valve is usually termed the timing valve, because it

determines the time of the explosion. Since the valves have each to act

once in every two revolutions, they cannot be operated by cams or

eccentrics placed directly on the crank shaft. The valve shaft D is

driven at half the rate of revolution of the crank shaft C by means of

the skew or worm gear E, one wheel of which is mounted on the crank

shaft and the other on the valve shaft. Ignition is accomplished by

means of a metal tube heated to incandescence by a Bunsen burner. At the

proper moment the ignition or timing valve is opened, and the mixed gas

and air under pressure being admitted to the interior of the tube, the

inflammable gases come into contact with the incandescent metal surface

and ignite; the flame at once spreads back to the cylinder and fires its

contents, thus producing the motive explosion.

The working parts are as follows:--A the piston, B the connecting rod,

C the crank shaft, D the side or valve shaft, E the skew gearing, F

the exhaust valve, G the exhaust valve lever, H the exhaust valve cam,

I the charge inlet valve, J the charge inlet valve lever, K the

charging valve cam, L the gas inlet valve, M the gas valve cam, N

lever and link operating gas valve, O igniting or timing valve, P

timing valve cam, Q timing valve lever or tumbler, R igniting tube, S

governor, T water jacket and cylinder, U Bunsen burner for heating

ignition tube. On the first forward or charging stroke the charge of

gas and air is admitted by the inlet valve I, which is operated by the

lever J from the cam K, on the valve shaft D. The gas supply is

admitted to the inlet valve I by the lift valve L, which is also

operated by the lever and link N from the cam M, controlled, however,

by the centrifugal governor S. The governor operates either to admit

gas wholly, or to cut it off completely, so that the variation in

power is obtained by varying the number of the explosions.

Since the engine shown in figs. 1 to 3 was built further modifications

have been made, principally in the direction of dispensing with or

diminishing port space, that is, so arranging the ports that the

compression space is not broken up into several separate chambers. In

this way the cooling surface in contact with the intensely hot gases

is reduced to a minimum. This is especially important when high

compressions are used, as then the compression space being small, the

port spaces form a large proportion of the total space. For maximum

economy it is necessary to get rid of port space altogether; this is

done by making the lift valves open directly into the compression

space. This arrangement can be readily made in small- and medium-sized

engines, but in the larger engines it becomes necessary to provide

ports, so as to allow the valves to be more easily removed for

cleaning.

The construction of pressure gas plant in 1878 by J.E. Dowson for the

production of inflammable gas from anthracite and coke by the action of

air mixed with steam, soon led to the development of larger and larger

Otto cycle engines. The gas obtained consisted of a mixture of carbon

monoxide, hydrogen, nitrogen and some carbon dioxide and oxygen, having

a lower heating value of about 150 British thermal units per cubic foot.

With this gas these engines used about 1 lb. of anthracite per b.h.p.

per hour.

From the pressure producer sprang the suction producer first placed on

the market in practical form by M. Benier of Paris in 1894, but then

presenting many difficulties which were not removed till about nine

years later when Dowson and others placed effective suction plants in

use in considerable numbers. Such suction plants are now built by all

the leading gas engine constructors for powers varying from 10 to 500

i.h.p.

[Illustration: FIG. 2.--Plan of Otto Cycle Engine.]

Dr Ludwig Mond and Crossley Bros. also attacked the problem of the

bituminous fuel producer, of which many examples are now at work for

powers as large as 2000 i.h.p. In 1895 B.H. Thwaite demonstrated that

the so-called waste gas from blast furnaces could be used in gas

engines, and this undoubtedly led to the design and construction of the

very large gas engines now becoming common both in Europe and in

America. It appears from Thwaite's experiments that the surplus gas from

the blast furnaces of Great Britain is capable of supplying at least

three-quarters of a million horse-power continuously day and night, and

it is calculated that in America nearly three million horse-power is

available from this source. Thwaite's system was put into operation in

1895 at the Glasgow Iron Works, and it was also successfully applied

near Barrow-in-Furness. For many reasons the system did not take

immediate root in England, but in 1898 the Societe Cockerill of Seraing

near Liege applied an engine designed by Delamere-Deboutteville to

utilize blast furnace gas. This engine indicated 213 h.p. running at 105

revolutions per minute. This was followed in 1899 by an engine giving

600 b.h.p. at 90 revolutions per minute used for driving a blowing

cylinder for a blast furnace. It had a single cylinder of 51.2 in.

diameter and a piston stroke of 55.1 in. About 1900 the Gasmotoren

Fabrik Deutz built an Otto cycle engine of 1000 b.h.p. having four

cylinders each 33 in. diameter and 39.3 in. stroke, speed 135

revolutions per minute. It was coupled direct to a dynamo. Crossley

Bros. Ltd. took up the large gas engine at an early date, and a 400 h.p.

engine by them was at work at Brunner, Mond & Co.'s works, Winnington,

in 1900; it had two cylinders of 26 in. diameter and 36 in. stroke, and

it ran at 150 revolutions per minute.

[Illustration: FIG. 3.--End Elevation of Otto Cycle Engine.]

Gas engines operating on the Otto cycle are usually of the single acting

open cylinder type up to about 200 b.h.p., but for the larger engines

closed cylinders of the double acting type are used. The engine then

closely resembles a double acting steam engine. It has a cylinder cover

with packing box of a special type, and, in addition to the water jacket

surrounding the cylinder and combustion spaces, the piston and piston

rod are hollow and cooling water is forced through them by a pump. Such

a double acting cylinder gives two succeeding power impulses and then

two charging strokes so that one revolution of the crank shaft is

occupied in charging and compression, while the succeeding revolution

gets two power impulses. For still larger engines two such double acting

cylinders are arranged in tandem, so that one piston rod runs through

two pistons and connects to a slide in front and to one crank pin by a

connecting rod. Such an engine gives two power impulses for every

revolution of the crank shaft. The greatest power developed in one

double acting cylinder is claimed by Ehrhardt and Sehmer for a cylinder

of 45-1/4 in. diameter by 51-1/4 in. stroke, which at 94 revolutions per

minute gives 1100 i.h.p.

_Two-Cycle Engine._--While the Otto or four-cycle engine was developing

as above described, inventors were hard at work on the two-cycle engine.

In Britain this work fell mostly upon Clerk, Robson and Atkinson, while

on the continent of Europe the most persevering and determined worker

was Koerting.

Dugald Clerk began work on the gas engine at the end of 1876. His first

patent was dated 1877 and dealt with an engine of the air pressure

vacuum type. His next patent was No. 3045 of 1878, and the engine there

described was exhibited at the Royal Agricultural Show at Kilburn,

London, 1879. In it a pump compressed a mixture of air and gas into a

reservoir, from which it entered the motor cylinder during the first

part of its stroke. After cut-off ignition was caused by a platinum

igniter, the piston was driven forward, and exhausting was performed on

the return stroke. This engine gave three b.h.p., and it was the first

compression explosion engine ever run giving one impulse for each

revolution of the crank shaft. It had difficulties, however, which

prevented it from reaching the market.

The particular type of engine now widely known as operating on the Clerk

cycle was patented in 1881 (Brit. Pat. No. 1089). One of the earliest of

these engines was set up at Lord Kelvin's laboratory at the Glasgow

university and used for the purpose of driving a Siemens dynamo and

supplying his house with electric light. The engine was first exhibited

in the Paris Electrical Exhibition of 1881 and the London Smoke

Abatement Exhibition of the same year. In this engine the charge was not

compressed by a separate pump. A pumping cylinder, it is true, was used,

but its function was to act merely as a displacer to take in a mixture

of gas and air and transfer it to the motor cylinder at as low a

pressure as possible, in such a way that the entering charge displaced

the exhaust gases through ports which were opened by the overrunning of

the piston. The motor piston thus timed and controlled the exhaust

discharge, and gave a power impulse for every revolution of the crank.

Engines of the Clerk type were built largely by Messrs Sterne & Co. of

Glasgow, the Clerk Gas Engine Co. of Philadelphia, U.S.A., the Campbell

Gas Engine Co., and a modification was made and sold in considerable

numbers by the Stockport Company. The lapsing of the Otto patent,

however, in 1876 caused engineers to neglect the two cycle for a time,

although a little later it was introduced for small engines in an

ingenious and simple modification known as the Day engine. This

two-cycle engine later became very popular, especially for motor launch

work. The Clerk cycle is now much in use for large gas engines up to

about 2000 horse as modified by Messrs Koerting of Hanover.

The Clerk cycle engine, as built in 1881, is shown in sectional plan

at fig. 4. The engine contains two cylinders--a power cylinder A and a

displacer cylinder B. The function of the displacer cylinder is to

take in a combustible charge of gas and air and transfer it to the

power cylinder, displacing as it enters the exhaust gases of the

previous explosion. A compression space G is formed at the end of the

motor cylinder A. It is of conical shape and communicates with the

displacer cylinder B by means of a large automatic lift valve which

opens into the compression space from a chamber communicating by a

pipe with the displacer cylinder. At the out-end of the motor cylinder

are placed V-shaped ports E which open to the atmosphere by an exhaust

pipe. The outward travel of the motor piston C causes it to overrun

these ports, as seen in fig. 4, and allows the pressure in the

cylinder to fall to atmosphere. The action of the engine is as

follows:--The displacer piston D on its forward movement draws in its

charge of gas and air, and it is so timed with reference to the motor

piston C that it has returned a small portion of its stroke just when

the motor piston overruns the exhaust ports. The overrunning of the

exhaust ports at once causes the pressure in the cylinder to fall to

atmosphere, and then the pressure in the displacer overcomes the

pressure in the motor cylinder and opens the lift valve, when the

charge flows in to the motor cylinder through the conical compression

space and displaces the exhaust gases through the ports E, while it

fills up the cylinder A with the inflammable charge. The exhaust gases

are sufficiently displaced and the fresh charge introduced into the

cylinder by the time the motor piston has opened the exhaust ports E

on the out-stroke and closed them on the return stroke. The two

cylinders are so proportioned that the exhaust gases are expelled as

completely as possible and replaced by fresh explosive mixture without

any material part of this mixture escaping with the exhaust. Unless

the proportions are carefully made such an escape is possible. The

relative operations of the motor piston C and the displacer piston D

are secured by advancing the crank of the displacer about a right

angle compared to the motor crank. The motor piston on its in-stroke

compresses the mixed charge into the conical space G; and, when

compression is complete, the mixture is ignited by the slide valve F.

This produces the power explosion which forces the piston forward

until the exhaust ports are opened again. By this cycle of operations

one power impulse is given for every revolution of the crank. The

motor cylinder is surrounded by a water jacket in the usual manner,

but it is unnecessary to water-jacket the displacer, as the gases are

never hot.

[Illustration: FIG. 4.--Sectional Plan of Clerk Cycle Engine, 1881.]

Robson also invented two-cycle engines. His first patent was taken out

in 1877 (No. 2334). The engines described in his patents of 1879-1880

were of the two-cycle type, and in them no second cylinder was used.

The front end of the motor cylinder was enclosed by a cover and

packing box, and was used as a pump to force gas and air into a

reservoir at a few lb. above atmosphere. The motor piston was arranged

to overrun ports in the side of the cylinder, but the exhaust

discharge was not timed in that way. A separate lift valve controlled

the overrun ports and determined when the exhaust should be

discharged. When the exhaust was discharged at the end of the stroke

the pressure from the gas and air reservoir was admitted by a lift

valve to the cylinder to displace the remaining exhaust gases and fill

the cylinder with charge. This mixture was compressed into a space at

the end of the cylinder and ignited by means of a flame ignition

device. Robson's engine was built in considerable numbers by Messrs

Tangye of Birmingham, the first exhibited by them at Bingley Hall at

the end of 1880. The modern Day engine closely resembles the Robson

engine so far as its broad operations are concerned.

Atkinson's work on the gas engine was begun in 1878, his first patent

being No. 3212 of 1879. The engine described in that patent somewhat

resembled the 1878 engine of Clerk as exhibited at Kilburn. Atkinson

was ingenious and persevering in the invention of two-cycle engines.

Two of his engines were made in considerable numbers. The first was

known as the "Differential" engine, exhibited at the Inventions

Exhibition, London, in 1885. A later engine produced by him was called

the "Cycle" engine, and it proved to be the most economical of all the

motors tested at the Society of Arts trials of motors for electric

lighting in 1888-1889. Atkinson joined Crossley Bros., and many of his

ingenious contrivances are now at work on the well-known engines of

that firm.

Four-cycle engines now practically monopolize the field of the smaller

internal combustion engines, and very large engines are also constructed

on this plan. The two-cycle, or Clerk cycle engines, however, compete

strongly with the four-cycle for large gas engines using blast furnace

gas. Koerting engines on the Clerk cycle are now built giving 1000

i.h.p. per double acting motor cylinder, and one power cylinder on this

method gives two impulses per revolution. Messrs Mather & Platt build a

Koerting engine of a modified type in England; an engine of their

construction with a power cylinder of about 29 in. and 40-1/2 in. stroke

gives 700 b.h.p.

Fig. 5 shows in longitudinal section the power and pump cylinders of a

Mather & Platt Koerting engine on the Clerk cycle; the power cylinder

section is shown above that of the pump cylinders, but it is to be

understood that both cylinders are in the same horizontal plane as in

the Clerk engine shown at fig. 4. The Koerting engine, however, is

double acting, whereas the Clerk engine was single acting. The power

cylinder A has a power piston A^1 and compression spaces A^2 A^3. At

the centre of the cylinders are exhaust ports E which open to the

atmosphere and are overrun by the piston A^1 at both ends of the

stroke. A^4 and A^5 are inlet valves for gas and air. The single

acting pump cylinders BB^1 supply the air required for the charge, and

the double acting gas cylinder CC^1 supplies the gas. Both gas and air

are led from these cylinders by separate passages to the inlet valves

A^4 A^5. The air pump pistons are lettered B^2 B^3 and the gas pump

piston C^2. The main crank D connects as usual to the piston rod of

the power piston A^1, and the pump crank F to the trunk air pump

piston B^2 which drives the other air pump piston B^3 and the gas pump

piston C^2 by a piston rod passing through all three. The gas mixture

is not made until the inlet valves A^4 A^5 are reached, so that no

explosive mixture exists until it is formed within the cylinder A. The

air is first introduced into the power cylinder to discharge some of

the hot gases, and when the gas is also admitted the contents of the

cylinder are cooled to some extent. The action of the engine is

exactly as described with regard to the Clerk cycle, and the

arrangement of the two cranks at about right angles to each other is

also similar. The exhaust is discharged through the ports E, and the

incoming charge fills the cylinder in the same way as in the Clerk

engine.

[Illustration: FIG. 5.--Longitudinal Section of Two-Cycle Engine

(Koerting-Clerk), new type, by Messrs Mather & Platt, Ltd.]

Another large continental gas engine, known as the Oechelhauser,

operates on a modified Clerk cycle and is shown in sectional plan at

fig. 6. The motor cylinder A has two pistons A^1 A^2, A^1 being

operated by a centre and A^2 by two outside cranks, side rods, and

cross head; the pistons A^1 A^2 thus move in opposite directions and

give an effective stroke of double that due to one crank. B is the air

and gas pump dealing with air on one side of its piston and gas on the

other. A chamber C opens to an air reservoir supplied from the pump

and to the power cylinder by ports C^1; a similar chamber D opens to a

gas reservoir supplied from the pump and to the power cylinder by

ports D^1. The exhaust ports E are provided at the other end of the

cylinder. When the front piston overruns the exhaust ports E the

pressure within the power cylinder falls to atmosphere; the back

piston then opens the air ports C^1 and air under slight pressure

flows in, to be followed a little later by gas under slight pressure

from the gas ports D^1. In this way the power cylinder A is charged

with gas and air mixture at each stroke, and when the pistons A^1 A^2

approach each other the charge is compressed into the space between

and then ignited by the electric spark. The pistons are then forced

apart and perform their power stroke. The Oechelhauser engine, which

is built in Great Britain by Messrs Beardmore of Glasgow, has attained

considerable success in driving blowing pumps for blast furnaces, in

producing electric light, and in driving iron rolling mills.

Large gas engines are undoubtedly making great progress, as will be

seen from the following interesting particulars prepared in 1908 by Mr

R.E. Mathot of Brussels giving the numbers and horse power of large

gas engines which had then been recently manufactured in Europe:--

[Illustration: FIG. 6.--Arrangement of Oechelhauser Gas Engine.]

Messrs Crossley Brothers, Limited, 57 motors, with an aggregate of

23,660 h.p.; Messrs Ehrhardt & Sehmer, 59 motors, total, 69,790 h.p.;

the Otto Gasmotoren Fabrik, 82, total 47,400 h.p.; Gebruder Koerting,

198, total 165,760 h.p.; Societe Alsacienne, 55, total 23,410 h.p.;

Societe John Cockerill, 148, total 102,925 h.p.; Societe Suisse,

Winterthur, 67, total 8620 h.p.; Vereinigte Maschinenfabriken,

Augsburg and Nurnberg, 215, total 256,240 h.p. The mean power of each

gas engine made by Messrs Ehrhardt & Sehmer and the Augsburg and

Nurnberg companies is in each case 1200 h.p. It is stated that in one

factory there are gas engines representing a total output of 35,000

h.p. These European large gas engines thus give nearly 575,000 h.p.

between them.

The installation of large gas engines has made considerable progress

in America. Mr E.L. Adams estimated that 350,000 h.p. was at work or

in construction in the United States in 1908. The first large engines

were installed at the works of the Lackawanna Steel Co., Buffalo, New

York. They were of the Koerting-Clerk type, and were built by the De

La Vergne Co. of New York. They included 16 blowing engines, each of

2000 h.p., and 8 engines of 1000 h.p. each, driving dynamos to produce

electric light. This large power plant was started in 1902. The

Westinghouse Co. of Pittsburgh have also built large engines, several

of which are in operation at the various works of the Carnegie Steel

Co. These Westinghouse engines are of the horizontal twin tandem type,

having two cranks and four double-acting cylinders in each unit, the

cylinders being 38 in. in diameter and the stroke 54 in. The Snow

Steam Pump Co. have built similar horizontal tandem engines with

cylinders of 42 in. diameter and 54 in. stroke. The English

Westinghouse Co. have also designed large gas engines, and they

exhibited a very interesting vertical multiple cylinder gas engine

having four cranks and eight single-acting cylinders, four pairs, in

tandem, at the Franco-British Exhibition of 1908; it gave 750 h.p.,

and the pistons were not watered.

Over two million horse-power of the smaller gas engines are now at

work in the world, and certainly above one million horse-power of

petrol motors.

The application of large gas engines to marine work, the compounding of

the gas engine, and many other matters are being strenuously pursued.

Capitaine of Frankfort-on-Main has built several vessels used for towing

purposes in which the vessel is driven by gas engines operated by means

of suction gas-producers consuming anthracite. Messrs Thornycroft and

Messrs Beardmore in Great Britain have adopted the Capitaine designs,

and both firms have applied them to sea-going vessels, Thornycroft to a

gas launch which has been tested in the Solent, and Beardmore to an old

gunboat, the "Rattler." The "Rattler" was fitted with five-cylinder Otto

cycle engines and suction gas-producers giving 500 i.h.p.; and has

sailed some 1500 m. under gas power only. There are many difficulties to

be overcome before large light and sufficiently slow-moving gas engines

can be installed on board ship, but progress is being made, and without

doubt all difficulties will be ultimately surmounted and gas power

successfully applied to ships for both large and small power.

The flame and incandescent tube methods of ignition have been displaced

by electrical ignition of both high and low tension types; all large gas

engines are ignited electrically and generally by more than one igniter

per cylinder.

The governing of large gas engines, too, is now effected so as to keep

up continuity of impulses by the method either of throttling the charge

inlet or by varying the point of admission of gas alone or air and gas

mixed.

It may be said, indeed, without exaggeration, that the whole world is

now alive to the possibilities of the internal-combustion motor, and

that progress will be more and more rapid. This motor has almost

fulfilled the expectations of those engineers who have devoted a large

part of their lives to its study and advancement. They are looking

forward now to the completion of the work begun so many years ago, and

expect, at no distant date, to find the internal-combustion motor

competing with the steam engine even in its latest form, the steam

turbine, on sea as vigorously as it does at present on land.

_Thermal Efficiency of Four-Cycle Engines._--The Otto and Clerk type

engines are usually designated respectively four-cycle and two-cycle,

because in the Otto type four strokes are necessary to complete the

power-producing cycle of the engine and in the Clerk engine two

strokes complete the cycle.

Indicated thermal efficiency may be defined as the proportion of the

total heat of combustion which appears as work done by the explosion

and expansion upon the piston. Brake thermal efficiency may be defined

as the proportion of the total heat of combustion which appears as

work given out by the engine available for overcoming external

resistances; that is, brake thermal efficiency is the effective

efficiency of the engine for doing work. In the early gas engines the

indicated thermal efficiency was only 16%, as shown by tests of Otto

engines from about 1877 to 1882, but now indicated thermal

efficiencies of from 35% to 37% are often obtained. Some experimenters

claim even higher efficiencies, but even 37% is higher than ordinary

best practice of 1909. Table I. has been prepared to show this

advance. It shows, in addition to indicated thermal efficiency, the

brake thermal efficiency and the mechanical efficiency, together with

other particulars such as engine dimensions, types and names of

experimenters. It will be seen that brake thermal efficiency has also

increased from 14% to 32%; that is, practically one-third of the whole

heat of combustion is obtained by these engines in effective work

available for all motive power purposes.

TABLE I.--_Indicated and Brake Thermal Efficiency of Four-Cycle

Engines from 1882 to 1908._

+---+-----------+------------------+------+---------------+-----------+-----------+------------------+

| |Mechanical | Names of | | Dimensions | Indicated | Brake | Type of |

|No.|Efficiency.| Experimenters. | Year.| of Engine. | Thermal | Thermal | Engine. |

| | | | | |Efficiency.|Efficiency.| |

+---+-----------+------------------+------+---------------+-----------+-----------+------------------+

| | Per cent. | | | Diam. Stroke. | Per cent. | Per cent. | |

| 1 | 87.6 | Slaby | 1882 | 6.75"X13.7" | 16 | 14 | Deutz |

| 2 | 84.2 | Thurston | 1884 | 8.5" X14" | 17 | 14.3 | Crossley |

| 3 | 86.1 | Society of Arts | 1888 | 9.5" X18" | 22 | 18.9 | Crossley |

| 4 | 80.9 | Society of Arts | 1888 | 9.02"X14" | 21 | 17 | Griffin (6-cycle)|

| 5 | 87.3 | Kennedy | 1888 | 7.5" X15" | 21 | 18.3 | Beck (6-cycle) |

| 6 | 82.0 | Capper | 1892 | 8.5" X18" | 22.8 | 17.4 | Crossley |

| 7 | 87.0 | Robinson | 1898 | 10" X18" | 28.7 | 25 | National |

| 8 | 83 | Humphrey | 1900 | 26" X36" | 31 | 25.7 | Crossley |

| 9 | 81.7 | Witz | 1900 | 51.2" X55.13" | 28 | 22.9 | Cockerill |

|10 | 85.5 | Inst. Civil. Eng.| 1905 | 14" X22" | 35[1] | 29.9 | National |

|11 | 77.1 | Burstall | 1907 | 16" X24" | 41.5[2] | 32 | Premier |

|12 | 87.5 | Hopkinson | 1908 | 11.5" X21" | 36.8 | 32.2 | Crossley |

+---+-----------+------------------+------+---------------+-----------+-----------+------------------+

_Thermal Efficiency of Two-Cycle Engines._--It has been found that

two-cycle engines present greater practical difficulties in regard to

obtaining high indicated and brake thermal efficiencies, but the

thermodynamic considerations are not affected by the practical

difficulties. As shown by Table II., these engines improved in

indicated thermal efficiency from the value of 16.4% attained in 1884

to 38% in 1903, while the brake thermal efficiency rose in the same

period from 14% to 29%. The numbers in Table II. are not so well

established as those in Table I. The four-cycle engines have been so

far subjected to much more rigid and authoritative tests than those of

the two-cycle. It is interesting to see from the table that the

mechanical efficiency of the early Clerk engines was 84%, while in the

later large engines of the same type it has fallen to 75%.

_Standards of Thermal Efficiency_.--To set up an absolute standard of

thermal efficiency it is necessary to know in a complete manner the

physical and chemical properties and occurrences in a gaseous

explosion. A great deal of attention has been devoted to gaseous

explosions by experimenters in England and on the continent of Europe,

and much knowledge has been obtained from the work of Mallard and Le

Chatelier, Clerk, Langen, Petavel, Hopkinson and Bairstow and

Alexander. From these and other experiments it is possible to measure

approximately the internal energy or the specific heats of the gases

of combustion at very high temperatures, such as 2000 deg. C.; and to

advance the knowledge on the subject a committee of the British

Association was formed at Leicester in 1907. Recognizing, in 1882,

that it was impossible to base any standard cycle of efficiency upon

the then existing knowledge of gaseous explosions Dugald Clerk

proposed what is called the air standard. This standard has been used

for many years, and it was officially adopted by a committee of the

Institution of Civil Engineers appointed in 1903, this committee's two

reports, dated March 1905 and December 1905, definitely adopting the

air-standard cycle as the standard of efficiency for internal

combustion engines. This standard assumes that the working fluid is

air, that its specific heat is constant throughout the range of

temperature, and that the value of the ratio between the specific heat

at constant volume and constant pressure is 1.4. The air-standard

efficiency for different cycles will be found fully discussed in the

report of that committee, but space here only allows of a short

discussion of the various cycles using compression previous to

ignition.

TABLE II.--_Indicated and Brake Thermal Efficiency of Two-cycle

Engines from 1884 to 1908_.

+-----------+---------------+------+-------------+-----------+-----------+--------------+

|Mechanical | Name of | | Dimensions | Indicated | Brake | Type of |

|Efficiency.| Experimenter. | Year.| of Motor | Thermal | Thermal | Engine. |

| | | | Cylinders. |Efficiency.|Efficiency.| |

+-----------+---------------+------+-------------+-----------+-----------+--------------+

| Per cent. | | |Diam. Stroke.| Per cent. | Per cent. | |

| 84 | Garrett | 1884 | 9" X 20" | 16.4 | 14 | Clerk-Sterne |

| .. | Stockport Co. | 1884 | .. .. | .. | 11.2 | Andrews & Co.|

| 83 | Clerk | 1887 | 9" X 15" | 20.2 | 16.9 | Clerk-Tangye |

| .. | Atkinson | 1885 | 7-1/2" .. | .. | 15 | Atkinson |

| 75 | Meyer | 1903 | 26-5/8" X | 38 | 29 | Oechelhauser |

| | | | (2"X37-1/2")| | | |

| 75 | Mather & Platt| 1907 | .. .. | 30.6 | 23 | Koerting |

+-----------+---------------+------+-------------+-----------+-----------+--------------+

For such engines there are three symmetrical thermodynamic cycles, and

each cycle has the maximum thermal efficiency possible for the

conditions assumed. The three types may be defined as cycles of (1)

constant temperature, (2) constant pressure, and (3) constant volume.

The term constant temperature indicates that the supply of heat is

added at constant temperature. In this cycle adiabatic compression is

assumed to raise the temperature of the working fluid from the lowest

to the highest point. The fluid then expands at constant temperature,

so that the whole of the heat is added at a constant temperature,

which is the highest temperature of the cycle. The heat supply is

stopped at a certain period, and then the fluid adiabatically expands

until the temperature falls to the lowest temperature. A compression

operation then takes place at the lowest temperature, so that the

necessary heat is discharged by isothermal compression at the lower

temperature. It will be recognized that this is the Carnot cycle, and

the efficiency E is the maximum possible between the temperature

limits in accordance with the well-known second law of

thermo-dynamics. This efficiency is E = (T - T^1)/T = 1 - T^1/T, where

T is the absolute temperature at which heat is supplied and T^1 the

absolute temperature at which heat is discharged.

It is obvious that the temperatures before and after compression are

here the same as the lower and the higher temperatures, so that if t

be the temperature before compression and t_c the temperature after

compression, then E = 1 - t/t_c. This equation in effect says that

thermal efficiency operating on the Carnot cycle depends upon the

temperatures before and after compression.

The constant pressure cycle is so called because heat is added to the

working fluid at constant pressure. In this cycle adiabatic

compression raises the pressure--not the temperature--from the lower

to the higher limit. At the higher limit of pressure, heat is added

while the working fluid expands at a constant pressure. The

temperature thus increases in proportion to increase of volume. When

the heat supply ceases, adiabatic expansion proceeds and reduces the

pressure of the working fluid from the higher to the lower point.

Again here we are dealing with pressure and not temperature. The heat

in this case is discharged from the cycle at the lower pressure but at

diminishing temperature. It can be shown in this case also that E = 1

- t/t_c, that is, that although the maximum temperature of the working

fluid is higher than the temperature of compression and the

temperature at the end of adiabatic expansion is higher than the lower

temperature, yet the proportion of heat convertible into work is

determined here also by the ratio of the temperatures before and after

compression.

The constant volume cycle is so called because the heat required is

added to the working fluid at constant volume. In this cycle

adiabatic compression raises the pressure and temperature of the

working fluid through a certain range; the heat supply is added while

the volume remains constant, that is, the volume to which the fluid is

diminished by compression. Adiabatic expansion reduces the pressure

and temperature of the working fluid until the volume is the same as

the original volume before compression, and the necessary heat is

discharged from the cycle at constant volume during falling

temperature. Here also it can be shown that the thermal efficiency

depends on the ratio between the temperature before compression and

the temperature after compression. It is as before E = 1 - t/t_c.

Where t is the temperature and v the volume before compression, and

t_c the temperature and v_c the volume after adiabatic compression, it

can be shown that (vc/v)^([gamma]-1) = t/t_c, so that E may be written

/vc\^([gamma]-1)

E = 1 - ( -- ) ,

\v /

and if v_c/v = 1/r, the compression ratio, then

/1\^([gamma]-1)

E = 1 - ( --) .

\r/

Thus in all three symmetrical cycles of constant temperature, constant

pressure and constant volume the thermal efficiency depends only on

the ratio of the maximum volume before compression to the volume after

compression; and, given this ratio, called 1/r, which does not depend

in any way upon temperature determinations but only upon the

construction and valve-setting of the engine, we have a means of

settling the ideal efficiency proper for the particular engine. Any

desired ideal efficiency may be obtained from any of the cycles by

selecting a suitable compression ratio. Table III., giving the

theoretical thermal efficiency for these three symmetrical cycles of

constant temperature, pressure and volume, extends from a compression

ratio of 1/2 to 1/100th. Such compression ratios as

TABLE III.--_Theoretical Thermal Efficiency for the Three Symmetrical

Cycles of Constant Temperature, Pressure and Volume._

1/r E | 1/7 0.55

1/2 0.026 | 1/10 0.61

1/3 0.36 | 1/20 0.70

1/4 0.43 | 1/100 0.85

1/5 0.48 |

100 are, of course, not used in practice. The ordinary value in

constant volume engines ranges from 1/5th to 1/7th. In the Diesel

engine, which is a constant pressure engine, the ratio is usually

1/12th. As the value of 1/r increases beyond certain limits, the

effective power for given cylinder dimensions diminishes, because the

temperature of compression is rapidly approaching the maximum

temperature possible by explosion; thus a compression of 1/100th

raises the temperature of air from 17 deg. C. to about 1600 deg. C,

and as 2000 deg. C. is the highest available explosion temperature for

ordinary purposes, it follows that a very small amount of work would

be possible from an engine using such compressions, apart from other

mechanical considerations. It has long been recognized that constant

pressure and constant volume engines have the same thermal efficiency

for similar range of compression temperature, but Prof. H.L. Callendar

first pointed out the interesting fact that a Carnot cycle engine is

equally dependent upon the ratio of the temperature before and after

compression, and that its efficiency for a given compression ratio is

the same as the efficiencies proper for constant pressure and constant

volume engines. Prof. Callendar demonstrated this at a meeting of the

Institution of Civil Engineers Committee on thermal standards in 1904.

The work of this committee, together with Clerk's investigations,

prove that in modern gas-engines up to to 50 h.p. it may be taken that

the best result possible in practice is given by multiplying the

air-standard value by .7. For instance, an engine with a compression

ratio of one-third has an air-standard efficiency of 0.36, and the

actual indicated efficiency of a well-designed engine should be .36

multiplied by .7 = 0.25. If, however, the compression ratio be raised

to one-fifth, then the air-standard value .48 multiplied by .7 gives

.336. The ideal efficiency of the real working fluid can be proved to

be about 20% short of the air-standard values given. (D. C.)

FOOTNOTES:

[1] The value 35% is deduced by the author from the Inst. C.E.

Committee's values.

[2] This value is, in the author's view, too high; probably due to

indicator error.

GASKELL, ELIZABETH CLEGHORN (1810-1865), English novelist and

biographer, was born on the 29th of September 1810 in Lindsay Row,

Chelsea, London, since destroyed to make way for Cheyne Walk. Her

father, William Stevenson (1772-1829), came from Berwick-on-Tweed, and

had been successively Unitarian minister, farmer, boarding-house keeper

for students at Edinburgh, editor of the _Scots Magazine_, and

contributor to the _Edinburgh Review_, before he received the post of

Keeper of the Records to the Treasury, which he held until his death.

His first wife, Elizabeth Holland, was Mrs Gaskell's mother. She was a

Holland of Sandlebridge, Knutsford, Cheshire, in which county the family

name had long been and is still of great account. Mrs Stevenson died a

month after her daughter was born, and the babe was carried into

Cheshire to Knutsford to be adopted by her aunt, Mrs Lumb. Thus her

childhood was spent in the pleasant environment that she has idealized

in _Cranford_. At fifteen years of age she went to a boarding-school at

Stratford-on-Avon, kept by Miss Byerley, where she remained until her

seventeenth year. Then came occasional visits to London to see her

father and his second wife, and after her father's death in 1829 to her

uncle, Swinton Holland. Two winters seem to have been spent in

Newcastle-on-Tyne In the family of William Turner, a Unitarian minister,

and a third in Edinburgh. On the 30th of August 1832 she was married in

the parish church of Knutsford to William Gaskell, minister of the

Unitarian chapel in Cross Street, Manchester, and the author of many

treatises and sermons in support of his own religious denomination. Mr

Gaskell held the chair of English history and literature in Manchester

New College.

Henceforth Mrs Gaskell's life belonged to Manchester. She and her

husband lived first in Dover Street, then in Rumford Street, and finally

in 1850 at 84 Plymouth Grove. Her literary life began with poetry. She

and her husband aspired to emulate George Crabbe and write the annals of

the Manchester poor. One poetic "Sketch," which appeared in _Blackwood's

Magazine_ for January 1837, seems to have been the only outcome of this

ambition. Henceforth, while in perfect union in all else, husband and

wife were to go their separate literary ways, Mrs Gaskell to become a

successful novelist, whose books were to live side by side with those of

greater masters, Mr Gaskell to be a distinguished Unitarian divine,

whose sermons, lectures and hymns are now all but forgotten. In her

earlier married life Mrs Gaskell was mainly occupied with domestic

duties--she had seven children--and philanthropic work among the poor.

Her first published prose effort was probably a letter that she

addressed to William Howitt on hearing that he contemplated a volume

entitled _Visits to Remarkable Places_. She then told the legend of

Clopton Hall, Warwickshire, as she had heard it in schooldays, and

Howitt incorporated the letter in that book, which was published in

1840. Serious authorship, however, does not seem to have been commenced

until four or five years later. In 1844 Mr and Mrs Gaskell visited North

Wales, where their only son "Willie" died of scarlet fever at the age of

ten months, and it was, it is said, to distract Mrs Gaskell from her

sorrow that her husband suggested a long work of fiction, and _Mary

Barton_ was begun. There were earlier short stories in _Howitt's

Journal_, where "Libbie Marsh's Three Eras" and "The Sexton's Hero"

appeared in 1847. But it was _Mary Barton: A Tale of Manchester Life_

that laid the foundation of Mrs Gaskell's literary career. It was

completed in 1847 and offered to a publisher who returned it unread. It

was then sent to Chapman & Hall, who retained the manuscript for a year

without reading it or communicating with the author. A reminder,

however, led to its being sought for, considered and accepted, the

publishers agreeing to pay the author L100 for the copyright. It was

published anonymously in two volumes in 1848. This story had a wide

popularity, and its author secured first the praise and then the

friendship of Carlyle, Landor and Dickens. Dickens indeed asked her in

1850 to become a contributor to his new magazine _Household Words_, and

here the whole of _Cranford_ appeared at intervals from December 1851 to

May 1853, exclusive of one sketch, reprinted in the "World's Classics"

edition (1907), that was published in _All the Year Round_ for November

1863. Earlier than this, indeed, for the very first number of _Household

Words_ she had written "Lizzie Leigh." Mrs Gaskell's second book,

however, was _The Moorland Cottage_, a dainty little volume that

appeared at Christmas 1850 with illustrations by Birket Foster. In the

Christmas number of _Household Words_ for 1853 appeared "The Squire's

Story," reprinted in _Lizzie Leigh and other Tales_ in 1865. In 1853

appeared another long novel, _Ruth_, and the incomparable _Cranford_.

This last--now the most popular of her books--is an idyll of village

life, largely inspired by girlish memories of Knutsford and its people.

In _Ruth_, which first appeared in three volumes, Mrs Gaskell turned to

a delicate treatment of a girl's betrayal and her subsequent rescue.

Once more we are introduced to Knutsford, thinly disguised, and to the

little Unitarian chapel in that town where the author had worshipped in

early years. In 1855 _North and South_ was published. It had previously

appeared serially in _Household Words_. Then came--in 1857--the _Life of

Charlotte Bronte_, in two volumes. Miss Bronte, who had enjoyed the

friendship of Mrs Gaskell and had exchanged visits, died in March 1855.

Two years earlier she had begged her publishers to postpone the issue of

her own novel _Villette_ in order that her friend's _Ruth_ should not

suffer. This biography, by its vivid presentation of the sad, melancholy

and indeed tragic story of the three Bronte sisters, greatly widened the

interest in their writings and gave its author a considerable place

among English biographers. But much matter was contained in the first

and second editions that was withdrawn from the third. Certain

statements made by the writer as to the school of Charlotte Bronte's

infancy, an identification of the "Lowood" of _Jane Eyre_ with the

existing school, and the acceptance of the story of Bramwell Bronte's

ruin having been caused by the woman in whose house he had lived as

tutor, brought threats of libel actions. Apologies were published, and

the third edition of the book was modified, as Mrs Gaskell declares, by

"another hand." The book in any case remains one of the best biographies

in the language. An introduction by Mrs Gaskell to the then popular

novel, _Mabel Vaughan_, was also included in her work of this year 1857,

but no further book was published by her until 1859, when, under the

title of _Round the Sofa_, she collected many of her contributions to

periodical literature. _Round the Sofa_ appeared in two volumes, the

first containing only "My Lady Ludlow," the second five short stories.

These stories reappeared the same year in one volume as _My Lady Ludlow

and other Tales_. In the next year 1860 appeared yet another volume of

short stories, entitled _Right at Last and other Tales_. The title story

had appeared two years earlier in _Household Words_ as "The Sin of a

Father." In 1862 Mrs Gaskell wrote a preface to a little book by Colonel

Vecchj, translated from the Italian--_Garibaldi and Caprera_, and in

1863 she published her last long novel, _Sylvia's Lovers_, dedicated "to

My dear Husband by her who best knows his Value." After this we have--in

1863--a one-volume story, _A Dark Night's Work_, and in the same year

_Cousin Phyllis and other Tales_ appeared. Reprinted short stories from

_All the Year Round_, _Cornhill Magazine_, and other publications, tend

to lengthen the number of books published by Mrs Gaskell during her

lifetime. _The Grey Woman and other Tales_ appeared in 1865.

Mrs Gaskell died on the 12th of November 1865 at Holyburn, Alton,

Hampshire, in a house she had just purchased with the profits of her

writings as a present for her husband. She was buried in the little

graveyard of the Knutsford Unitarian church. Her unfinished novel _Wives

and Daughters_ was published in two volumes in 1866.

Mrs Gaskell has enjoyed an ever gaining popularity since her death.

_Cranford_ has been published in a hundred forms and with many

illustrators. It is unanimously accepted as a classic. Scarcely less

recognition is awarded to the _Life of Charlotte Bronte_, which is in

every library. The many volumes of novels and stories seemed of less

secure permanence until the falling in of their copyrights revealed the

fact that a dozen publishers thought them worth reprinting. The most

complete editions, however, are the "Knutsford Edition," edited with

introductions by A.W. Ward, in eight volumes (Smith, Elder), and the

"World's Classics" edition, edited by Clement Shorter, in 10 volumes

(Henry Froude, 1908).

There is no biography of Mrs Gaskell, she having forbidden the

publication of any of her letters. See, however, the biographical

introduction to the "Knutsford" _Mary Barton_ by A.W. Ward; the

_Letters of Charles Dickens_; _Women Writers_, by C.J. Hamilton,

second series; _H.B. Stowe's Life and Letters_, edited by Annie

Fields; _Autobiography of Mrs Fletcher_; _Mrs Gaskell and Knutsford_,

by G.A. Payne; _Cranford_, with a preface by Anne Thackeray Ritchie;

_Ecrivains modernes de l'Angleterre_, by Emile Montegut.

(C. K. S.)