MALCS, fcTIEXXE LOUIE 



MALUS, KTIBNNK LOUIS. 



7 



BfJaBBinal duttM, preached regularly :o his turn in the college chapel, 

 a*d enjoyed UM society of hU family and friend*. He wai taken ill 



(uddecUy. when 



Ml-rf-1 



in strong health, while on a visit to hi* 

 Mr. Kekoml), at Bath, where he died December 29, 1834. 

 He loft a widow and a .on and .laughter. 



Wham boy. and while at Cambridge, Malthui displayed a great love 

 of ogh<iag for affatinf 's ak, a keen iierception of the ludicrous, much 

 fslhV frr wit and humour, and considerable comic power of imitation; 

 bat kit character gradually changed : he retained indeed hi* cheerful- 

 Mi* end ptayfuJnce*, bat lie became placid, temperate, patient, and 

 forbeario*; wider the obloquy which wa heaped upon him. His 

 Banners wen kind and gentle, hi* conTenation mild but earnest and 

 imprrir, hi* deportment gentlemanly. In politic* he wa* a Whig 

 aad a decided advocate of all aalutary reforms, but itrongly attached 

 to the institution* of hi* country, aud fearful of all imperfectly consi- 

 dered chance* irt*^ innovationa. 



The following k a liat of hi* works in the order in which they were 

 pahfiahed: _ 



1, ' An Kseey on the Principle of Population, as it affects the future 

 Improvement of Society ; with Remark* on the Speculations of Mr. 

 Godin. M. Condorcet, and other Wriura,' Anonyiuou*, London, Svo, 

 1TM. 3, 'An Investigation on the cause of the preeent high Price of 

 containing an Illustration of the Nature and Limit* of 



Fair Price in Time of Scarcity, and it* Application to the particular 

 Stat* of thi* Country,' STO, 1800. 5, ' An Essay on the Principle of 



or te menment o te oor aw 

 Lord Onarille, occasioned by aom* 

 the Bast India Company'* Establish 

 G*fl Serrano,' So, 181S. 6, ' Obe 



Population; or a View of it* past and preeent Effects on human 

 Happiness ; with an Inquiry into our Prospect* respecting the future 

 Reoioval or Mitigation of the Evil* which it occasion*.' New edition, 

 410, 180*. 4, ' A Letter to Samuel Whitbreed, on hU proposed Bill 

 for the Amendment of the Poor Laws,' STO, 1807. 5, 'A Letter to 



i Observations of his Lordship on 

 bment for the Education of their 

 ' Observation* on the Effects of the 



Corn Law*, and of a Ra*e or Fall in the Price of Corn on the Agricul- 

 ture and general Wealth of the Country,' STO, 1814, 7, 'The Ground* 

 of an Opinion on the Policy of restricting the Importation of Foreign 

 Corn;' intended as an appendix to the 'Observations on the Corn 

 Laws,' STO, 1815. 8, 'An Inquiry into the Nature and Progreu of 

 Rent, and the Principle* by which it is regulated,' STO, 1815. This, 

 next to the Eesay on Population,' is Malthiu's most important work, 

 and that which has bad moet influence on opinion. 9, ' Statement* 

 respeetiof the East India College, with an Appeal to Facts in Refuta- 

 tion of the Charge, lately brought against it by the Court of Proprietors." 

 STO, 1817. 10, 'Principle* of Political Economy, considered with a 

 View to their Practical Application,' 8vo, 1820. 11, ' The Measure of 

 Value stated and illustrated ; with an Application of it to the Alteration 

 of the Value of the English Currency since 1700,' STO, 1823. 12, 

 Definition, in Political Economy, preceded by an Inquiry into the 

 Rale* which ought to guide Political Economist* in the Definition and 

 t'e* of their Terms,' STO, 1827. 18, ' A Summary View of tho Prin- 

 ciple of Population/ 1890. (From the 'Supplement to the Encyclopedia 

 Bntennira,') 



( Jfoaev of JfaiiAai by Dr. Otter, late Bishop of Chichester, prefixed 

 to the ' Principle, of Political Economy.') 



MAM'S, Kin I "IS, a di.tingui.hed philosopher and 



military engineer, was bora at Paris, June 23rd 1775. He receive.) 

 hi* Ant leawn* under the eye* of hi* father, Anne Louis Malus of 

 Mitry ; and, in rarly youth, his time appears to have been nearly 

 equally divided between classical and mathematical studies. This 

 insUelous ooabinatioo of the two great branches of education had the 

 esf|list eftect in expanding the mind of the pupil HU memory 

 was ver* retentive, and it i* said that, oven nrar the close of his life, 

 he could rrpeat several pauages of the ' Iliad ' of considerable length. 

 Bis early taete for classical literature is hown by the fact that, 

 when seventeen yean of ago, he had written a tragedy entitled 'The 

 DsathofCeio ; ' but nibeequently hi* studies were almost exclusively 



At the USM that the tragedy is said to havs been written, young 

 Hah** was, after a ttrlct examination, in which he acquitted himiHf 

 to the satisfaction of UM parsons in authority, admitted as a pupil in 

 th. ftcolc da Oani* MUiteir*, It being the intention of his father that 

 he should enter into that branch of the public service ; and he i* said 

 to have immediately distinguished himself by hi* diligence and hi* 

 Isimtlni teieau. From ome canae however which is not explained, 

 to probably because hi. father, who held the post of Treasurer of 

 France, had become suspected by the government (the great revolu- 

 tion having oommeoced), he was dismissed from the Institution ; and 

 either from choice or compulsion, he entered the army as a private 

 toldlsr. He wa* for a short lime employed in that catdty, with the 

 >** to which be was attached, In repairing the fortifications of 

 Dunkirk. Hot on UM termination of th* reign of terror, tho govern- 

 MthaTing decided upon the formation of the fcoolc Polytectnique, 

 inquiry was made for a certain number of young men, who, having 

 completed th. *ual course of education, might b. the first to receive 

 attraction to toe higher branches of science; and it is recorded to 

 the honour of M U Per*, the commandant of the engineers at Dun- 

 kirk, that, knowing the gnat talents of th* young soldier, he withdrew 

 him ImsaedUlely from the ranks and cent him to Paris with a 



recommendation to the celebrated Monge. Mains was immediately 

 admitted, and was joined in a clans, with about twenty other persons 

 to attend a course of instruction in mathematics physics, and engi- 

 neering. During three yearn he i : his studies with extra- 

 ordinary ardour, and distinauished himself by hU applications of 

 analysis to the solutions of some intricate propositions; he is said 

 also to have occasionally delivered lecture* on mathematical subjects. 

 It is added that he then commenced those researches concerning tho 

 properties of light, which prepared the way for his subsequent dis- 

 | oo varies in optics; and his first step in this brilliant career consisted 

 ! in investigating the path of a ray of light after being reflected from 

 or refracted into a medium having a surface of any form. 



On quitting the Koole Polytechnique, Malus was for a time employed 

 as a professor of mathematics in the military school at Metz ; but 'the 

 smallness of his fortune, his family having suflVred great losses during 

 the revolution, and perhaps an inclination in favour of a more active 

 life, induced him to abandon the project which he at one time enter- 

 tained of devoting himself entirely to the sciences. He then-fora 

 entered the corps of engineers with the rank of captain ; aud. i 

 he wa* sent to join the Army of the Sambre and Meuse. He accom- 

 panied that army across the Rhine, and was present at the actions of 

 Ukratz and Altenkirk. 



At the termination of the campaign Malus went to Paris, and, in 

 the following year, he embarked with the expedition to Egypt uuder 

 Bonaparte. He was engaged in the battle of the Pyramids and in the 

 affair of Chebrees : he was also employed as an engineer at the sieges 

 of El Arish and Jaffa; and, after the taking of the latter plac--. lie 

 was appointed to superintend the repair of its fortifications. While 

 performing this duty he fell ill of the plague, and lay for some time 

 in the military hospital which he bad assisted to form : be recovered 

 however with little aid from medicine, and he waa almost immediately 

 sent to fortify Damietta. He was afterwards engaged in the action 

 with the Turkish forces which landed at Aboukir ; he was also at tho 

 battle of Heliopolis, at the affair of Coraim, and at the surrender of 

 Cairo. 



When the Institute was founded in that city, he wa appointed one 

 of its members ; and in the first volume of the ' Decade Egyptienne ' 

 there is an account of an excursion which he made far into the country, 

 with his discovery of a branch of the Nile which had not before been 

 noticed. Mains continued in Egypt till the remains of the French 

 army capitulated, when, in ISO], he returned to hi* native country in 

 an English vessel Exhausted by the arduous services in which he had 

 been engaged, and with his health nearly ruined, he yet performed 

 the duties of an officer of engineers, having, in 1S04, been appointed 

 by the government to superintend tho construction of the works which 

 were being added to the fortifications of Antwerp. He had then tho 

 title of sub-director of fortifications, and he was made a member of 

 the Legion of Honour. Five years afterwards he was appointed 

 superintendent of bsrracks in the department of the Seine ; aud in the 

 following year, 1810, he waa made a member of tho Committee of 

 Fortifications and Lieutenant-Colonel of Engineers. 



Almost immediately on his return to France, Malus married a 

 daughter of Koch, the Chancellor of the University of Qiessen, to 

 whom he became attached before his departure for Egypt; and, 

 during the ret of his life, all the time he could spare from bis pro- 

 fessional avocations was spent in the cultivation of the sciences, par- 

 ticularly in the continuation of those optical investigations which he 

 had commenced at the Kcole Polytechnique. His first published 

 work was entitled ' Traitd d'Optique,' in which he treated the pheno- 

 mena of the reflection and refraction of light as they were then known ; 

 and he particularly distinguished himself by bis experiments and 

 researches concerning the reflection of light in transparent media. It 

 was known that when a pencil of light has entered into glass at a 

 considerable angle of incidence, the internal reflection takes place 

 either before it arrives at the posterior surface, or at a c 

 distance from that surface on the exterior ; but it had been found 

 impossible to determine, though an inequality in the angles of 

 reflection in the two cases waa manifest, to which of the cases either 

 of the observed reflections should be referred. Malus overcame this 

 difficulty by applying successively to the surface an opaque ni, 

 which, by preventing the reflection of the emergent raya, proved that 

 1 the observed reflection had taken place within the glass, and a trans- 

 parent medium, which, by permitting the rays to pass quite through 

 the glos, afforded a reflection from the exterior of the latter. 



The subject of double refraction in crystals was very imperfectly 

 known, when, in 1S08, the Institute of France offered a premium for 

 the best Mumoire on the subject; and Malus immediately entered 

 with ardour into this field of research. It was while prosecuting his 

 experiments that there occurred to him one of those fortunate acci- 

 dents which only men of genius have tho power of rendering available 

 a* step* to great discoveries. He then resided at Paris, and, happen- 

 ing one day to direct a prism of crystal which he held in bis hand_o 

 one of the windows of the Luxembourg palace, on which there was 

 a brilliant light produced by the reflected rays of the setting sun, In 

 was surprised to find that, while turning the crystal round, one of the 

 images produce.! by the double refraction in it varied in intensity, and 

 alternately appeared and disappeared. As such phenomena had not 

 been observed when the prism was directed to any other bright object, 



