THE CENTENARY OF THE BUNSEN BURNER GEORG LOCKEMANN Miihle Hollenstedt, Germany (Translated by R a l p h E. Oesper)
ALMOST a11 discoveries and inventions have a previous history, which in some instances extends over years, decades, and even centuries, as in the case of the discovery of oxygen; on the other hand, novel, unexpected, and even undreamed of events can occur, such as the discovery of X-rays, radium, and the fission of the uranium nucleus. Consequently, it is not surprising that there were forerunners to the Bunsen burner, whose centenary should have been one of the highlights in the 1955 calendar of historical celebrations. These predecessors represent unsuccessful attempts to use the same basic principle. Once brought to the stage of practical usefulness, this laboratory device was rapidly adopted in laboratories throughout the world and its adaptations to domestic and industrial needs followed in swift order. It would be hard to picture our present civilization without this efficient means of burning gas to produce heat. By this achievement alone, Bunsen became one of the great scientific benefactors of our era. In 1852 Robert Wilhelm Bunsen (1811-99) was called from the University of Breslau to succeed Leopold Gmelin (1788-1853) as professor of chemistry at Heidelberg. Here he inherited an old laboratory, which, like the one he had just left in Breslau, had formerly been a monastery. It is not surprising that one of his stipulations when accepting the call was that a riwre 1 new laboratory was to be built according to his own plans. He moved into the new building a t Easter, 1855. With its large auditorium, 50 working places, special rooms, etc., it was the largest and best equipped teaching laboratory in all Germany. It was soon filled to capacity with enthusiastic students, especially because Giessen, hitherto the Mecca of chemical training, had lost its appeal when the great Liebig had gone to Munich in 1852 with the express proviso that he be relieved of all laboratory instruction. Like many other German cities, Heidelberg had acquired a gas works to light the streets. The plant went
into production in October, 1852, i. e., just when Bunsen took over his new chair. He had long wrestled with charcoal and coal furnaces, and with alcohol lamps, and was seeking a better means not only of lighting his laboratory, but also of providing better sources of heat for laboratory operations. Consequently, he included the necessary piping in the new laboratory. However, the devices for burning gas then available all suffered from the grave defect that they delivered luminous smoky flames of low heating power. Bunsen, a selfconfident inventive genius, was sure that he could devise a suitable burner. When his brilliant student Henry Roscoe (18331915) came hack from his vacation, he brought from London an Argand burner, whose essential feature was a copper cone which could he slid up and down along the tube of the burner, and whose top consisted of wire gauze. Presumably this was closely allied to the burner described by Michael Faraday in his "Chemical Manipulations," published in 1827. Bunsen tried it out and rejected it. The flame was too large, it was difficult to regulate, and the gas was so diluted that the resulting temperature was too low. Furthermore, the flame flickered excessively. Bunsen set to work and in a short time came up with an astoundingly simple solution to this complex problem. Instead of feeding the flame with air from the outside, he prepared the gas-air mixture previous to the combustion. In this way he found that he could produce nonluminous flames of high heating value. He took his ideas to the university mechanic, Peter Desaga, and by the time Bunsen moved into the new laboratory in the spring of 1855, Desaga had manufactured enough burners for the Heidelberg students and soon was supplying the demands that came from all quarters of the chemical world.' Bunsen did not publish an account of the burner until two years later. This description, accompanied by a cut, appeared in a joint paper with Roscoe,*the second in the series on their photochemical studies. He spoke of the burner in the modest terms so characteristic of all his descriptions of his o m inventions and discoveries. He writes of the new heating device:
. which one of us has devised and introduced in d a c e of the The author is indebted to Mr. Erioh Fecht of Heidelberg, present owner of the firm C. Desaga, Factory for Scientific Apparatus (founded by Carl Dessgs, the son of Peter Desags) for information regarding the latter. Poggendorffs A m Physik, 100, 84-5 (1857).
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VOLUME 33, NO. 1, JANUARY 1956 wire gauze burners in the laboratory here, and whioh is better suited than any other appliance far producing steady flames of different luminosity, color, and form. The principle of this burnerissimply that city gas is dowed to issue under such conditions that by its own movement it carries along and mixes with .
..
in this paper] a is an ordinary crass cut burner rising in the renter of the cylindrical space b to the same height as the surface of the cube eecc. The cylindrical space b, which is 15 mm. deep and has s. diameter of 10 mm., communicates n.ith the outside air t,hrough the four holes d, whieh me 7 mm. in diameter. If the tuhe ee, whieh is 8.5 mm. wide and 75 mm. long, is screwed into the cylinder, and the city gas is allowed to flow into it through the burner a, it sucks in so much air through the openings d that it burns at the month of the tube e with a nanluminous, perfectly soot-fre~ flame. The brightness of the gas thus mixed with sir hardly exceeds that of a hydrogen flame. After the openings d srr closed, the bright and sooting illuminating gas flame reappears.
The burner evidently was used for some years in the form described and pictured here, namely, with four air holes in the square block. In any case, the illustrations (Figure 2) in the papers entitled "Lotrohrversuche" ("Studies with the blowpipe") and "Chemische Analyse durch Spektralbeobachtungenm still show the same model. When it was desired to obtain a somewhat or completely luminous flame, it was necessary to stop up several or all four holes. There is no record of the date a t which the four holes in the cubical base of t,he burner were replaced by the now general two larger holes in the burner tube along with the rotatable perforated ring. I t is quite likely that this improvement mas contrihuted hy Desaga. Neither Bunsen nor Desaga applied for patent protection on the new hurner. As was to be expected, it was not long before others produced imitations of the strikingly useful appliance, and some went so far as to claim the invention as their own. As early as 1855 Desaga found it necessary to send a note to the Dingler Polytechnische Journal refuting the allegation by the firm Julius Pintsch of Berlin that the burner mas their brainchild. On Mav 22, Bunsen sent Desaga a written declaration that the latter had employed a principle outlined by Bunsen as the basis for the construction, in a very ingenious manner, of a gas burner whose mechanical details mere developed by the apparatus Ann., 111, 257 (1859); PogAnn. Physik, 110, 161 (1860). The three illustrations accompanying this paper were kindly provided by Dr. Rudolf Sschtleben, section chief in the Deutsches Museum in Munich. Unfortunately, neither the museum nor the Desxge. firm in Heidelberg has any specimens of the original Runsen burner. qendo&
Ixgm
'
maker himself. With this it was possible to obtain a sootless, nonluminous flame. In his (Bunsen's) opinion, Mr. Desaga had constructed a burner which doubtless has contrihuted materially to the use of illuminating gas for heating purposes. A second attempt to pirate the invention was made by R. W. Elmer, a gas engineer of Berlin, who went so far as to obtain a patent on the burner in the Kingdom of Hannover. The patent was dated January 4, 1856, and had a life of five years. Desaga, of course, attacked this procedure. He stated5 that as early as the fall of Dingle? Pol&chnisehe
Journal, 143,840 (1857).
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1854 he had received from the "Herrn Hofrath Bunsen" a commission to construct, in accord with the latter's specihxtions, a gas burner without a wire gauze and delivering a completely soot-free flame, and that when he finally succeeded after many trials, he equipped the new laboratory a t Heidelberg with 50 such burners. The further spread of the use of the burner is common knowledge. It soon rendered invaluable services to Bunsen himself. It was an essential tool in the photochemical studies he carried out with Roscoe from 1855
JOURNAL OF CHEMICAL EDUCATION
to 1862. It likewise made possible the joint researches with Gustav Kirchhoff (1824-87) which resulted in their spectral analytical triumphs (Figure 3). If the centennial of the bunsen burner brings once more to our minds the memory of the brilliant scientist, gifted inventor, and lovable gentleman, Robert Wilhelm Bunsen, who generously donated all the fruits of his wonderful skill and mind to the whole civilized world, we should certainly not forget to include in our gratitude his worthy technical collaborator, Peter Desaga.
