THOMAS 0. SISTRUNK Tulane University, New Orleans, Louisiana and nickel, exhibited crystalline type structures. In 1818 he published his first theoretical explanation of the density of crystals through a consideration of spherical atoms and their relation to structure and den~ity.~ In 1820, by the invention of the hygrometer, which bears his name, Daniell first gave precision to the means of determining the moisture of the atmo~phere.~Early in life he became interested in meteorological phenomena. This interest resulted in the publication of 13 papers and one book on meteorology in addition to 27 original contributions in other fields, primarily subjects of a chemical and physical nature. In 1823 he published his "Meteorological Essays." This was the first attempt to collect the scattered facts on this particular subject, and to explain the most important phenomena of the atmosphere by means of physical laws. His model record of atmospheric changes is indicative of his emphasis on extreme accuracy in scientific observations. He organized the plan adopted by the Horticultural Society for their annual Meteorological Reports which became the model from which the Greenwich Meteorological Reports were developed. Even though his pursuits shifted to other fields, his interest in meteorology continued. In 1839 he drew up the meteorological portion of the directions for the scientific observations to be made by government officers throughout the British Empire. In 1824, in an essay to the Horticultural Society, he called attention to the necessity of attending to the moisture of hothouses which caused a revolution in the construction of such establishments.' For this paper he received the Silver Medal of the Society. In 1830 Daniell constructed a barometer for the Royal Society in which water was used as the fluid instead of m e r c ~ r y . ~This required an instrument of enormous height, and only after mastering numerous problems of construction was his task completed. This barometer remained the most accurate in England for several years. He was engaged in its adjustment a few weeks before his death. In the same year he devised a pyrometer for the measurement of high temperatures.= By the use of this instrument Daniell determined the melting point of iron to be about 3400°F.'o From previous experi-
DANIELL,inventor of the Daniell J o m FREDERIC cell, is not considered a pioneer in the organization of a branch of chemistry or a school of thought, neither were his cont,ributions to the field of science as voluminous nor as outstanding as those of his contemporaries which include Faraday, Dumas, Avogadro, Berzelius, and Graham. His services, however, to more than one branch of science, were of the quality to merit not only the highest honor of the Royal Society, but every medal given by the Society. Only one account of the life of Daniell has been published. This is the obituary appearing in Philosophical Magazine.' Most of the references to Daniell's life are taken from this presentation made by the president of the Society, The Marquis of N o r t h a m p t ~ n . ~ John Frederic Daniell was born March 12, 1790, in a small tonn in England called Strand. His father, George Daniell, a Bencher of the Inner Temple, provided him xith a good classical education in his own home. His father had visions of his son becoming a minister, but showed no signs of disappointment when he exhibited an early fondness for scientific pursuits. As a young man he was given a position in the sugar refining establishment of a relative where he introduced important improvements in its manufacture. However, the rigors of business were of little interest to him and he soon surrendered his position. When he was 23 years old be was elected a Fellow of the Royal Society in whose activities he actively participated until his death. In 1814-15 Daniell began work on solutions and crystals in.rrhich he discovered and exhibited the advantages of the utilization of water and different solvents over mechanical division of crystals in determining crystalline ~tructures.~He noticed that if "amorphous alum" was left for some weeks in water it assumed a pyramidal form, and the lower part of it was embossed by distinct octahedral crystals. Borax exhibits similar properties giving rhomboidal crystals. Daniell concluded that ". . . in these cases the cohesion of the solid resisted unequally the solvent power of the liquid.. . ." Similar work followed in which he attempted the investigation of the structures of various metals and salts by observing the formation of -embossmentsupon dissolving the sample in suitable solvents.' He concluded that salts of some metals, including bismuth, antimony,
'I*id.,4,3-2(1818'. I&id., 8,29%336 (1820). THOMPSON, T., Ann. Phil., 27,114-30 (1826). Phil. Tmns., 122,539-74 (1832). 'Zbid., 120,257-86(1830). The present melting point of iron is considered to be 2793" F., from LANGE,N. A,, "Handbook of Chemistry," 7th ed., Handbwk Publishers, Inc., 1949.
Phil. May., 28,409-12 (1846). The amount was probably written by William Thomm Brande, Eeq., Chairman of the Chemistry Committee of the Royal Society. a THOMPSON, T., Ann. Phil., 6 , 4 5 4 5 (1815). ' Quarl. J . Sci., 2,278-93 (1817). 1
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JANUARY, 1952
ments by M. Guyton de Morveau, who used platinum expansion, Daniell calculated the melting point of iron to be 8696°F." In his attack on the assumptions made by de Morveau he points out the impracticability of the old pyrometer. This tremendous improvement in the accuracy of determining high temperatures won him the Rumford Medal. When King's College, London, was founded in 1831, Daniell was appointed Professor of Chemistry, where his attentions were turned to the phenomena presented by voltaic electricity. His interest in this particular problem had its roots in the experiments of Faraday.12 In Daniell's first letter to Faraday on voltaic combinations he exhibits proof of the source of his interest.la You know how deep an interest I have taken in your "Experimental Researches in Electricity," and how zealously I have availed myself of the opportunities, which you have ever kindly afforded me, of profiting by your oral explanation of such dificulties as occurred to me in the study of your last series of papers in the Philosophical Transactions.
It is in this publication that Daniell introduces an explanation of a constant voltaic combmation which is still in use and has become a classical illustration of a battery. While repeating some of the experiments of Faraday, Daniell became conscious of the need for a voltaic combination which would furnish a constant force of sufficient magnitude to allow a prolonged investigation of the principles of electrolysis advanced by Faraday. He promptly discovered the cell which carries his name. In repeating Faraday's experiments using this new cell, which produced a constant current for days of contiuuous operation, Daniell happily reported that he observed no deviations from the results reported by Faraday. He published his findings in the same letter in which he described his cell. An unfortunate incident made this simultaneous report possible. The notes of all experiments made by Daniell on the constant cell and subsequent experiments were lost. This necessitated his repeating all experiments of importance, the results of which were published in 1836, almost one year later than they should have been had this incident not occurred. Five additional letters on voltaic combinations and subsequent applications supplemented the first, the last appearing in the Philosophical Transactions in 1842.14 For this very important contribution to the scientific world, the Royal Society in 1836 awarded him their highest medal, the Copley Medal. In 1839 Daniell's book, "Introduction to Chemical Philosophy," was published. This volume mas perhaps the most original book on the subject published in this period. For work on the electrolysis of salt solutions he was awarded the Royal Medal in 1842, the same year that he received the honoraly degree of Doctor of Civil Law from Oxford. The first publication on this Phil. Trans., 120,260 (1830).
" Faraday's laws of electmlysis were published in 1834. 18 Phil. Tmns.. 126.107(1836). " Ibid., 130,1i7-56 (18&). '
problem appeared in 1840.15 He started from the fundamental principle that "the force which is measured by its definite action a t any one point of a circuit cannot perform more than one equivalent proportion of work a t any other point of the same circuit." Applying this principle to the results of the measurements he made of the quantities of hydrogen and oxygen liberated a t the cathode and anode during the electrolysis of aqueous sulfuric acid, sodium sulfate, and potassium sulfate, and of the quantities of the same gases liberated by passing the same current, simultaneously, through acidulated water, Daniell concluded that the water was not decomposed in the changes, but only the acid or the salt was electrolyzed. He concluded that the salt was separated into two ions, "an anion composed of one equivalent of sulphur and four equivalents of oxygen, and the metallic cathion sodium." He gave the following electrolytic formulas to the salts he examined: Chemical formula
Sulphate of Soda Sul~hateof Potassa. Nitrate of Potassa Phosphate of Soda Sulphate of Copper
(S
+ 3 0 ) + (Na + 0 )
(S+3O)+(Ka+O)
Elecl~dylie formala (S 4 0 ) Ne
+
+
(S+40)+Ra
+ 5 0 ) + (Ka + 0 ) (N + 6 0 ) + Ka (P + Z1/lO) + (Na + 0 ) ( P + 3'/?0) + Na (S + 30) + (Cu + 0 ) (S + 4 0 ) + Cu (N
By a similar experiment Daniell concluded that salts of ammonia were compounds of negative ions with the positive radical ammonium. Measurements made by Daniell and MillerIp showed that although the quantities of the anion and the cation liberated at the electrodes were always strictly equivalent, the number of cations which travel to the cathode in a given time is usually not so large as the number of anions whioh travel to the anode in the same time. They were searching for a means for studying in detail the quantitative ratio of transfer of ions to the electrodes. I t is very likely that a procedure would have been worked out for a thorough study had not Daniell's sudden death ended this work. This problem was solved by Hittorf in the years 1853 to 1859." On March 13, 1845, Daniell attended a council meeting of the Royal Society, of which he was foreign secretary, and shortly after commenting on an item of business was apparently seized with apoplexy. The attentions of the physicians present were fruitless and in five minutes his life had ended, a t 55 gears of age. He was survived by two sons and five daughters. His wife had died in 1834, only two years before Daniell made his greatest contribution to the scientific world, the constant battery. William Allen Miller, his cop
p
Phil. Mag., 17,349-56 (1840). '"Phil. Trans., 134, 1-19 (1844). "Ueber die Wanderungen der Ionen wiihrend der Elektrolyse," Pogg. Ann., 89,177; 98, 1; 103, 1; 106,336, 513 (1853 to 1859). Cited hv Mum. M. PATTIEON. "Historr of Chemical Theories and L&s,', ~ o h n Wiley & SO";, h e . , iYeb 1-ork, 1907. l6
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worker on the electrolysis of salts, succeeded him as Professor of Chemistry a t King's College. H i "Meterological Essays" appeared in a third edition the year of his death; his "Introduction to Chemical Philosophy" in a second edition in 1843. Both hooks were authoritative publications in their respective fields for several years after the author's death. His success as a teacher is, without a doubt, due, in part, to hi character and personality. The writer of his obituary states it thus:
JOURNAL OF CHEMICAL EDUCATION High as were his scientific attainments, he possessed others of a still lofty and more enduring character; to the sterling qualities of a vigorous understanding, and a kind and benevolent heart, he united the humble and unobtrusive piety of a sinoere Christian.'8
ACKNOWLEDGMENT
~h~ author, a graduate to thank Dr. Clara deMilt for suggesting the topic of this paper and for ,,,,ting the manuscript. Phil. Mag., 28,412 (1846).
