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.; Gebrüder Koerting, 198, total 165,760 h.p.; Société Alsacienne, 55, total 23,410 h.p.; Société John Cockerill, 148, total 102,925 h.p.; Société Suisse, Winterthur, 67, total 8620 h.p.; Vereinigte Maschinen

FIG. 6.-Arrangement of Oechelhäuser Gas Engine. fabriken, Augsburg and Nürnberg, 215, total 256, 240 h.p. The mean | power of each gas engine made by Messrs Ehrhardt & Sehmer and the Augsburg and Nürnberg 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.

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 TABLE I.-Indicated and Brake Thermal Efficiency of Four-Cycle Engines from 1882 to 1908.

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 Pittsburg 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 $4 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 singleacting 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 horsepower of petrol motors.

I

No.

Mechanical Names of
Efficiency. Experimenters.

Year.

Per cent.

Diam. Stroke.

Per cent.

Per cent.

87.6

Slaby

1882

6.75 X13.7

16

14

8.5 X14

17

14.3

Crossley

86.1

Society of Arts

1888

9.5" X18"

Crossley

80-9

Society of Arts

Griffin (6-cycle)

87.3

Kennedy

Beck (6-cycle)

82.0

Capper

1892

8.5" X18"

22-8

17.4

Crossley

87.0

Robinson

1898 10"

National

83

X36"

Crossley

81.7

Witz

Cockerill

Inst. Civil. Eng.

1905 14

X22

351

1907 16"

X24

41.52

32

Premier

12

87.5

1908 11.5 X21"

36.8

32.2

Crossley

2345678

Burstall
Hopkinson

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

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.
Thermal Efficiency of Two-Cycle Engines.-It has been found that
obtaining high indicated and brake thermal efficiencies, but the
two-cycle engines present greater practical difficulties in regard to
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
Committee's values.
The value 35% is deduced by the author from the Inst.C.E.

This value is, in the author's view, too high; probably due to indicator error.

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 re-
duces 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 È= 1-1/le. Where is the temperature and the volume
before compression, and t, the temperature and v. the volume after
adiabatic compression, it can be shown that
may be written

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° C.; and to advance the knowledge on the subject a com-
mittee 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 ap-
pointed 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
TABLE II.-Indicated and Brake Thermal Efficiency of Two-cycle Engines from 1884 to 1908.

and if v./v1/r, the compression ratio, then

so that E

Thus in all three symmetrical cycles of constant temperature, constant pressure and constant volume the thermal efficiency

Indicated Brake
Thermal Thermal
Efficiency. Efficiency.|
Per cent.

Type of Engine.

Per cent.
16.4

Stockport Co.

1884

83

Clerk

14 11.2 16.9

Atkinson

15

9" X 15"
1885 71
1903 26X(2"X371')

1907

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.

For such engines there are three symmetrical thermodynamic cycles, and cach 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

The term constant temperature indicates that the supply of heat is added at constant temperature. In this cycle adiabatic compres sion 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. 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!)/T = I-T/T, where T is the absolute temperature at which heat is supplied and T 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 be the temperature before compression and the temperature after compression, then E=1-tle. 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-l, 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.

Clerk-Sterne
Andrews & Co.
Clerk-Tangye
Atkinson

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 tooth. Such compression ratios as TABLE III.-Theoretical Thermal Efficiency for the Three Symmetrical Cycles of Constant Temperature, Pressure and Volume.

100 are, of course, not used in practice. The ordinary value
in constant volume engines ranges from th to th. In the
Diesel engine, which is a constant pressure engine, the ratio is
usually th. As the value of 1/7 increases beyond certain limits,
the effective power for given cylinder dimensions diminishes,
because the temperature of compression is rapidly approaching the
of 18th raises the temperature of air from 17° C. to about 1600° C.,
maximum temperature possible by explosion; thus a compression
and as 2000° 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 com-
mittee, 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.)

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 UniThe constant volume cycle is so called because the heat required tarian minister, farmer, boarding-house keeper for students at is added to the working fluid at constant volume. In this cycle | Edinburgh, editor of the Scots Magazine, and contributor to the

Edinburgh Review, before he received the post of Keeper of the Cranford. This last-now the most popular of her books-is an
Records to the Treasury, which he held until his death. His first idyll of village life, largely inspired by girlish memories of Knuts-
wife, Elizabeth Holland, was Mrs Gaskell's mother. She was a ford and its people. In Ruth, which first appeared in three
Holland of Sandlebridge, Knutsford, Cheshire, in which county volumes, Mrs Gaskell turned to a delicate treatment of a girl's
the family name had long been and is still of great account. Mrs betrayal and her subsequent rescue. Once more we are intro-
Stevenson died a month after her daughter was born, and the duced to Knutsford, thinly disguised, and to the little Unitarian
babe was carried into Cheshire to Knutsford to be adopted by her chapel in that town where the author had worshipped in early
aunt, Mrs Lumb. Thus her childhood was spent in the pleasant| years. In 1855 North and South was published. It had previously
environment that she has idealized in Cranford. At fifteen years appeared serially in Household Words. Then came-in 1857-
of age she went to a boarding-school at Stratford-on-Avon, kept the Life of Charlotte Brontë, in two volumes. Miss Brontë, who
by Miss Byerley, where she remained until her seventeenth year. had enjoyed the friendship of Mrs Gaskell and had exchanged
Then came occasional visits to London to see her father and his visits, died in March 1855. Two years earlier she had begged her
second wife, and after her father's death in 1829 to her uncle, publishers to postpone the issue of her own novel Villette in order
Swinton Holland. Two winters seem to have been spent in that her friend's Ruth should not suffer. This biography, by its
Newcastle-on-Tyne in the family of William Turner, a Unitarian vivid presentation of the sad, melancholy and indeed tragic
minister, and a third in Edinburgh On the 30th of August 1832 story of the three Brontë sisters, greatly widened the interest in
she was married in the parish church of Knutsford to William their writings and gave its author a considerable place among
Gaskell, minister of the Unitarian chapel in Cross Street, Man-English biographers. But much matter was contained in the
chester, 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. Sheand
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 Howill'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 £100 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 Collage, 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

first and second editions that was withdrawn from the third.
Certain statements made by the writer as to the school of
Charlotte Brontë's infancy, an identification of the "Lowood" of
Jane Eyre with the existing school, and the acceptance of the
story of Bramwell Brontë'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, 19c8). publication of any of her letters. See, however, the biographical There is no biography of Mrs Gaskell, she having forbidden the 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: G. A. Payne; Cranford, with a preface by Anne Thackeray Ritchie; Autobiography of Mrs Fletcher; Mrs Gaskell and Knutsford, by Écrivains modernes de l'Angleterre, by Emile Montégut. (C. K. S.)

GASSENDI1 [GASSEND), PIERRE (1592-1655), French philo- | bronze statue of him was erected by subscription at Digne in sopher, scientist and mathematician, was born of poor parents 1852. at Champtercier, near Digne, in Provence, on the 22nd of January 1592. At a very early age he gave indications of remarkable mental powers and was sent to the college at Digne. He showed particular aptitude for languages and mathematics, and it is said that at the age of sixteen he was invited to lecture on rhetoric at the college. Soon afterwards he entered the university of Aix, to study philosophy under P. Fesaye. In 1612 he was called to the college of Digne to lecture on theology. Four years later he received the degree of doctor of theology at Avignon, and in 1617 he took holy orders. In the same year he was called to the chair of philosophy at Aix, and seems gradually to have withdrawn from theology, He lectured principally on the Aristotelian philosophy, conforming as far as possible to the orthodox methods. At the same time, however, he followed with interest the discoveries of Galileo and Kepler, and became more and more dissatisfied with the Peripatetic system. It was the period of revolt against the Aristotelianism of the schools, and Gassendi shared to the full the empirical tendencies of the age. He, too, began to draw up objections to the Aristotelian philosophy, but did not at first venture to publish them. In 1624, however, after he had left Aix for a canonry at Grenoble, be printed the first part of his Exercitationes paradoxicae adversus Aristoteleos. A fragment of the second book was published later at La Haye (1659), but the remaining five were never composed, Gassendi apparently thinking that after the Discussiones Peripateticae of Francesco Patrizzi little field was left for his labours.

After 1628 Gassendi travelled in Flanders and Holland. During this time he wrote, at the instance of Mersenne, his examination of the mystical philosophy of Robert Fludd (Epistolica dissertatio in qua praecipua principia philosophiae Ro. Fluddi deleguntur, 1631), an essay on parhelia (Epistola de parkeliis), and some valuable observations on the transit of Mercury which had been foretold by Kepler. He returned to France in 1631, and two years later became provost of the cathedral church at Digne. Some years were then spent in travelling through Provence with the duke of Angoulême, governor of the department. The only literary work of this period is the Life of Peiresc, which has been frequently reprinted, and was translated into English. In 1642 he was engaged by Mersenne in controversy with Descartes. His objections to the fundamental propositions of Descartes were published in 1642; they appear as the fifth in the series contained in the works of Descartes. In these objections Gassendi's tendency towards the empirical school of speculation appears more pronounced than in any of his other writings. In 1645 he accepted the chair of mathematics in the Collège Royal at Paris, and lectured for many years with great success. In addition to controversial writings on physical questions, there appeared during this period the first of the works by which he is known in the history of philosophy. In 1647 he published the treatise De vita, moribus, el doctrina Epicuri libri octo. The work was well received, and two years later appeared his commentary on the tenth book of Diogenes Laërtius, De vila, moribus, et placitis Epicuri, seu Animadversiones in X. librum Diog. Laër. (Lyons, 1649; last edition, 1675). In the same year the more important Syntagma philosophiae Epicuri (Lyons, 1649; Amsterdam, 1684) was published.

In 1648 ill-health compelled him to give up his lectures at the Collège Royal. He travelled in the south of France, spending nearly two years at Toulon, the climate of which suited him. In 1653 he returned to Paris and resumed his literary work, publishing in that year lives of Copernicus and Tycho Brahe. The disease from which he suffered, lung complaint, had, however, established a firm hold on him. His strength gradually failed, and he died at Paris on the 24th of October 1655. A It was formerly thought that Gassendi was really the genitive of the Latin form Gassendus. C. Güttler, however, holds that it is a modernized form of the O. Fr. Gassendy (see paper quoted in bibliography).

His collected works, of which the most important is the Syn-
tagma philosophicum (Opera, i. and ii.), were published in 1658
by Montmort (6 vols., Lyons). Another edition, also in 6 folio
volumes, was published by N. Averanius in 1727. The first
two are occupied entirely with his Syntagma philosophicum;
the third contains his critical writings on Epicurus, Aristotle,
Descartes, Fludd and Lord Herbert, with some occasional
pieces on certain problems of physics; the fourth, his Institutio
astronomica, and his Commentarii de rebus celestibus; the
fifth, his commentary on the tenth book of Diogenes Laërtius,
the biographies of Epicurus, N. C. F. de Peiresc, Tycho Brahe,
Copernicus, Georg von Peuerbach, and Regiomontanus, with
some tracts on the value of ancient money, on the Roman
calendar, and on the theory of music, to all which is appended
a large and prolix piece entitled Notitia ecclesiae Diniensis;
the sixth volume contains his correspondence. The Lives,
especially those of Copernicus, Tycho and Peiresc, have been
justly admired. That of Peiresc has been repeatedly printed;
it has also been translated into English. Gassendi was one of
the first after the revival of letters who treated the literature
of philosophy in a lively way. His writings of this kind, though
too laudatory and somewhat diffuse, have great merit; they
abound in those anecdotal details, natural yet not obvious
reflections, and vivacious turns of thought, which made Gibbon
style him, with some extravagance certainly, though it was true
enough up to Gassendi's time--" le meilleur philosophe des
littérateurs, et le meilleur littérateur des philosophes."

Gassendi holds an honourable place in the history of physical
science. He certainly added little to the stock of human knowledge,
but the clearness of his exposition and the manner in which he, like
Bacon, urged the importance of experimental research, were of
inestimable service to the cause of science. To what extent any
place can be assigned him in the history of philosophy is more doubt-
ful. The Exercitationes on the whole seem to have excited more
attention than they deserved. They contain little or nothing
beyond what had been already advanced against Aristotle. The
first book expounds clearly, and with much vigour, the evil effects of
the blind acceptance of the Aristotelian dicta on physical and philo-
sophical study; but, as is the case with so many of the anti-Aristo-
telian works of this period, the objections show the usual ignorance
of Aristotle's own writings. The second book, which contains the
review of Aristotle's dialectic or logic, is throughout Ramist in tone
and method. The objections to Descartes-one of which at least,
through Descartes's statement of it in the appendix of objections
in the Meditationes has become famous-have no speculative value,
and in general are the outcome of the crudest empiricism. His
consistency inherent in the philosophical system raised on Epicurean-
labours on Epicurus have a certain historical value, but the want of
ism is such as to deprive it of genuine worth. Along with strong
expressions of empiricism we find him holding doctrines absolutely
irreconcilable with empiricism in any form. For while he maintains
which has not been in the senses" (nihil in intellectu quod non prius
constantly his favourite maxim" that there is nothing in the intellect
fuerit in sensu), while he contends that the imaginative faculty
(phantasia) is the counterpart of sense-that, as it has to do with
material images, it is itself, like sense, material, and essentially the
same both in men and brutes; he at the same time admits that the
intellect, which he affirms to be immaterial and immortal-the most
characteristic distinction of humanity-attains notions and truths of
which no effort of sensation or imagination can give us the slightest
apprehension (Op. ii. 383). He instances the capacity of forming
384), to which he says brutes, who partake as truly as men in the
general notions"; the very conception of universality itself (ib.
faculty called phantasia, never attain; the notion of God, whom he
says we may imagine to be corporcal, but understand to be in-
corporeal; and lastly, the reflex action by which the mind makes its
own phenomena and operations the objects of attention.
The Syntagma philosophicum, in fact, is one of those eclectic
systems which unite, or rather place in juxtaposition, irreconcilable
dogmas from various schools of thought. It is divided, according to
the usual fashion of the Epicurcans, into logic (which, with Gassendi
as with Epicurus, is truly canonic), physics and ethics. The logic,
which contains at least one praiseworthy portion, a sketch of the
history of the science, is divided into theory of right apprehension
(bene imaginari), theory of right judgment (bene proponere), theory
of right inference (bene colligere), theory of right method (bene
ordinare). The first part contains the specially empirical positions
which Gassendi afterwards neglects or leaves out of account. The
senses, the sole source of knowledge, are supposed to yield us im-
mediately cognition of individual things; phantasy (which Gassendi