October 31, 1912] 



NATURE 



•55 



confidence that the appeal will be widely responded 

 to. We would point out that it is not only the 

 large gifts of the wealthy that are sought, though 

 the)- are no doubt essential to the success of the 

 scheme, but also the smaller tributes of esteem, 

 the thank-offerings of those who recognise that 

 every household in the land is a debtor to the great 

 man who has passed from amongst us. 



Donations should be sent to the treasurers of 

 the Lister Memorial Fund, Royal Society, Burling- 

 ton House, W. 



M. LECOO DE BOISBAUDRAN.'^ 



IN the death of M. Lecoq de Boisbaudran, which 

 took place in May of the present year, there 

 passed from the field of activity one of the most 

 brilliant and energetic of French investigators. 

 Lecoq de Boisbaudran was an amateur in the true 

 sense of the word, and he had the faculty of con- 

 centrating the whole of his energy upon the 

 question of the moment. He was born in Cognac 

 in 1838. His parents were of noble family in Poitou, 

 but their circumstances prevented his receiving 

 more than an ordinary education. While a young 

 man, he studied mathematics under his uncle, who 

 had been a student at I'f^cole Polytechnique, but his 

 interest quickly became absorbed in the science 

 of chemistry ; he eventually succeeded in gaining 

 an entrance to the laboratory of Wiirtz at I'Kcole 

 de Medecine, and it was here that he made the 

 discovery of the element gallium. 



Among his earlier contributions to science are 

 papers on gravitation, meteorological phenomena, 

 and also upon matters connected with agriculture ; 

 but physical chemistrv and spectroscopy received 

 the greater share of his attention. The probable 

 existence of gallium had been foretold by 

 Mendeleeff, who had proposed the name eka- 

 aluminiiim, but to Lecoq de Boisbaudran belongs 

 the honour of the discovery and the isolation of 

 the element. In the field of spectroscopic research 

 his name may be classed with those of Kirchhoff, 

 Bunsen, Sir G. G. Stokes, and Sir William Crookes, 

 as one of the founders of the science of spectro- 

 chemistry. His " Spectres Lumineux," published in 

 1874, was one of the most perfect works on spectro- 

 scopy at that time, and it possesses considerable 

 value even at the present day; although limited to 

 the visible region, the drawings are marvellously 

 exact, and in the index wave-lengths of all the lines 

 in the fifty-six spectra shown are given in Angstrom 

 units to one place of decimals ; the labour in- 

 volved in the work was enormous. 



At the time when Lecoq de Boisbaudran was 

 in ihe prime of his scientific activity, the chemistry 

 of the rare earths was receiving considerable 

 attention, Cl^vc of L^psala, Marignac, Demarcay, 

 Crookes and others were hard at work in that 

 very interesting field of research, and he devoted 

 himself with all the energy of his nature to the 



1 An article from the pen of 1[. O. Urhain upon the life and work of 

 Lecoq de Boisbaudran appeared in the Kevue Geti^ralc ties Sciences for 

 September 15, and to that the present writer is indebted for several particulars 

 not otherwise available. 



work; during the period from 1880 to igoo his 

 communications to the Academy appeared in 

 almost every issue of the Comptes rendus. He 

 was successful in discovering and isolating the 

 elements samarium and dysprosium, and he very 

 completely investigated the body now known as 

 gadolinium, which had been provisionally named 

 Y a by Marignac. 



In his earlier investigations he depended largely 

 upon the indications given by the spark spectrum, 

 produced by passing an alternating spark between 

 electrodes immersed in a solution of the salts, and 

 also upon the absorption spectrum of the solution ; 

 the spectra of didymium, erbium, holmium, &c. , 

 were very fully examined by this latter method. 



At the time when the work of Sir William 

 Crookes upon the kathode phosphorescence 

 spectrum of the rare earths was published, he 

 made the observation that if the condensed spark 

 from one electrode was allowed to strike upon the 

 surface of a liquid containing a rare earth salt, 

 there was produced, just where the discharge 

 struck, a faint luminous spot, which, when exam- 

 ined with a spectroscope of low power, gave rise 

 to a series of faintly luminous bands, closely 

 resembling' the phosphorescent bands of Crookes ; 

 this he called the .reversal spectrum, and the method 

 of investigation was largely used by him in his 

 speculations upon the constitution of the yttria 

 earths. His conclusions in this particular were 

 in direct opposition to those of Crookes, who, as 

 the result of an extended series of observations 

 on the brilliant bands produced by kathode phos- 

 phorescence, had suggested that the element 

 yttrium was composed of a number of very closely 

 allied bodies, which he termed tneta-elements , 

 each producing a distinct phosphorescent spectrum. 

 M. de Boisbaudran, on the other hand, held the 

 opinion that yttria, when perfectly pure, did not 

 phosphoresce under kathode rays, and that the 

 bands observed by Crookes were due to impurities 

 contained in the yttria. 



The origin of the band-producing earths is by 

 no means clear even at the present day, but the 

 fact remains that although much work has been 

 since done upon the element yttria, no one has 

 succeeded in producing the non-phosphorescing 

 material of Lecoq de Boisbaudran. It is a great 

 misfortune that the numerous researches of Lecoq 

 de Boisbaudran, particularly those referring to the 

 rare earths, have not been collected together and 

 published in complete forin ; there are probably 

 few of the rare earth elements about which some 

 observation could not be found under his name ; 

 but, scattered as they are in isolated papers, they 

 are in large measure lost, and probably many of 

 his original observations will have to be re-made 

 by his successors. This, unfortunately, was 

 characteristic of the man. His method was to 

 work and publish almost simultaneously ; so 

 engrossed was he in his work that he cared little 

 for public recognition. 



The cross of the Legion of Honour was conferred 

 upon him for his discovery of the element gallium, 

 but he never officiallv received the Order. 



NO. 2244, VOL. 90] 



