NA TURE 



77 



THURSDAY, NOVEMBER 22, 1900. 



THE CORRESPONDENCE OF BERZELTUS 

 AND SCHONBEIN. 

 The Letters of Jons Jacob Berzehus and Christian Fried- 

 rich Schonbein, 1836-1847. Edited by Georg W. A. 

 Kahlbaum. Translated by Francis V. Darbishire» 

 Ph.D., and N V. Sidgwick. Pp. 112. (London, 

 Edinburgh and Oxford, Williams and Norgate, 1900.) 



IN collecting materials for the life of Schonbein, the 

 first instalment of which has already been noticed 

 in these columns. Dr. Kahlbaum has had placed at his 

 disposal all the correspondence, covering nearly fifty 

 years, left behind him by the illustrious discoverer of 

 ozone and gun-cotton. The letters of Faraday arid 

 Liebig have thus been made public, and we have now 

 an English edition of the letters which passed between 

 Berzelius and Schonbein, the original edition in German 

 having been prepared by the editor as a tribute to the 

 memory of Berzelius on the occasion of the commemo- 

 ration at Stockholm, on October 9, 1898, of the fiftieth 

 anniversary of the death of the great Swedish chemist. 

 The translators have added two of Schonbein's letters 

 written in 1847, and a paper by that author which was 

 not included in the German edition. Of the twenty-two 

 letters published in this little volume eight are by 

 Berzelius. 



Berzelius was senior to Schonbein by twenty years, and 

 it appears that the latter had about 1827 resolved to go 

 to Stockholm to complete his studies under the " con- 

 summate master of chemical science." In order to raise 

 the necessary funds he offered a London bookseller 

 (Koller) a translation of Berzelius' " Larbok i Kemien," 

 and about the same time he proposed to a German 

 acquaintance (Perthes, of Gotha) to supply a German 

 translation of Gay-Lussac's lectures on physics, which 

 he was then attending at the Sorbonne. Neither of these 

 schemes came to anything, and Schonbein was, as 

 already recorded in his life, invited to Bale as temporary 

 professor in 1828. The Swabian chemist thus never 

 came under the personal influence of his Swedish con- 

 temporary as a pupil, and the acquaintance was com- 

 menced in 1836 by a letter, in which Schonbein submitted 

 the results of his experiments on the passivity of iron. In 

 this letter, which is the first of the present series, he 

 describes himself to Berzelius as " a perfect stranger." 

 The reply, dated May 4, 1837, is interesting, not only 

 because it is the first communication from Berzelius, but 

 also because it at once emphasises the difference of 

 opinion which at that time separated the two schools of 

 " contact " and " chemical " electricians. Having sug- 

 gested that the iron by contact becomes charged with 

 opposite electricity, he goes on to say : 



" But of course you cannot admit the latter assump- 

 tion, since you accept De la Rive's view that electricity 

 of an opposite character cannot be produced by contact. 

 In this, however, I do not agree with you ; I am firmly 

 convinced that when we understand the cause of this 

 remarkable property of iron, we shall find in it one more 

 proof that Volta's conception was more profound and 

 nearer the truth than that of his opponents, who, by ad- 

 mitting that electricity and chemical affinity are different 



NO. 1621, VOL. 63] 



manifestations of the same force, acknowledge, though 

 without being conscious of so doing, that Volta was 

 right." 



In subsequent letters the prevailing note of the corre- 

 spondence is still the origin of the electric current and 

 the cause of polarisation. In his letter of October 14, 

 1838, Schonbein describes the polarisation of liquid 

 electrodes (hydrochloric acid) in a U-tube, and suggests 

 in explanation that the first step in the decomposition of 

 a molecule by electricity is, as it were, a preliminary 

 loosening of the affinities of the atoms : — " Between the 

 complete separation of two elements and their most 

 intimate chemical union there exist intermediate condi- 

 tions of combination, of which as yet we know nothing ; 

 unless indeed isomerism points to some such relation." 

 Berzelius (November 13, 1838) opposes this view, and 

 refers his correspondent to a theory of the galvanic 

 cell which he had advanced thirty-six years previously. 

 The reference to this theory has apparently given the 

 editor. Dr. Kahlbaum, some trouble, but he appears to 

 have identified it and appends a valuable bibliographical 

 footnote. Schonbein's reply (March 28, 1839) contains 

 further arguments against what he calls the "electro- 

 chemical theory," meaning, of course, the form of that 

 theory promulgated by Berzelius. He sums up in the 

 statement that " the act of chemical combination of the 

 elements is not due to the play of electrical forces, or, 

 in other words, that affinity and electricity are not the 

 same thing, though they are mutually dependent." 



The first reference to ozone in the present correspond- 

 ence is contained in a letter from Schonbein to Berzelius 

 dated September 11, 1840, in which he refers to the 

 " odoriferous principle " as having already been dis- 

 covered but not isolated in sufficient quantity to determine 

 its chemical characters. The reply to this communica- 

 tion, of which a copy by Schonbein has been found, was 

 kept by the Crown Prince, subsequently King Maximilian 

 II. of Bavaria, under somewhat interesting circumstances. 

 It appears that the first paper on ozone had been sent 

 by Schonbein to Prof. Schelling, who was then at Munich, 

 and the latter in his reply says : 



"In the person of our Crown Prince we possess a dis- 

 tinguished patron of research, especially on scientific 

 lines. Should you ever be unable from want of pecuniary 

 resources to begin a lengthy research, from which you 

 have grounds for expecting good results, let me know, 

 and it will give me great pleasure to awaken the interest 

 of our generous Prince on your behalf." 



On the strength of this recommendation Schonbein 

 applied for a grant in order to purchase a battery ; but 

 unfortunately the application was received by the Prince 

 just as he was leaving for Greece, and he took the 

 correspondence, including the letter from Berzelius 

 referred to above, away with him, so that nothing resulted 

 from the application. 



Passing on to the year 1844, there is a very long letter 

 addressed to Berzelius and containing a fairly complete 

 reiume of Schonbein's work on ozone down to that 

 period. It is of interest to read that he sends his corre- 

 spondent the bleached strip of paper which first " proved 

 the bleaching power of the electrical odour" on April 7, 

 1844. In this letter also we fini the view that nitrogen 

 is a hydride of ozone, and, in curious antithesis to existing 



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