Table of Contents
Transmutation of Lead
(1) A. Smits & A. Karssen
(1) Arthur Smits & A. Karssen
Prof. Arthur Smits and Dr. A. Karssen (Univ. of Amsterdam) published reports of their alleged transmutation of lead into mercury and thallium in 1924. Their work was inspired by that of Prof. Miethe, who claimed to have transformed mercury into gold in a modified Jaenicke mercury ultraviolet lamp. (4, 5)
The lamp was constructed of lead quartz. Two legs (A, B), ending in narrow tubes, contain two steel electrodes cemented with sealing wax. The electrodes were inserted in two small removable copper water coolers (G, H). Pure liquid lead was poured into storage vessel C, after which the open end was sealed off. The lead was kept liquid at 350o C by an electric furnace around C. Tube D contained capillary F and terminated in stopcock K, which was connected to a mercury diffusion pump (Fig. 5.1).
When a high vacuum was attained, vessel C was further heated with a Bunsen burner to dissociate all the oxide and gases. Stopcock K was then closed and disconnected from the pump. The apparatus was tilted so the liquid lead ran into the two legs (A, B) of the lamp. The legs of the lamp were heated to redness to drive off the gases from the electrodes, and the lamp was evacuated again. Then copper water coolers were placed around the legs, and the lamp was ready to use. At the end of the experiment, the liquid lead was returned to vessel C, which was continuously heated. The lead was specially prepared and purified by the firm of Kahlbaum of Berlin to prevent every contamination, especially mercury.
The experiment was monitored with a quartz spectroscope. After a current of 30-35 amperes/8 volts was passed through the system for 6 hours, a few mercury lines began to appear in the spectrum. After 10 hours, the entire series of lines of mercury, plus those of thallium, were apparent in the visible and ultraviolet spectrum.
In 1926, Smits and Karssen reported further developments of their experimental protocol. The lamp was redesigned, and the mercury diffusion pump was replaced by a mechanical pump to eliminate the possibility of contamination from that source. The use of a mercury manometer was avoided by employing a glass spring manometer. All the equipment was examined with a spectroscope to make certain it was free from mercury and thallium. They described their method as follows:
"After filling the storage vessel, the lamp and the lead were heated in high vacuum to redness. The lead oxide being dissociated, the liquid lead was as brilliant as mercury. Then the lead was brought into the lamp, and after ignition the spectrum was observed at 25 V/36 A, by a Hilger quartz-spectrograph. Further, the spectrum of a quartz mercury lamp was observed, and also the scale in such a way that, to facilitate comparison, the different spectra were adjacent. Thus we obtained the spectrum of the lead in its initial state. After that we burned the lamp at 40 A/80 V for 10 hours. After having done this the lead was poured into the storage vessel to obtain thorough mixing; the lead was then brought into the lamp again, and after ignition the spectrum was observed at 25 V/36 A. The result was that, whilst initially the lead spectrum showed only very weakly the mercury line 2536 in the ultra-violet, after 10 hours' burning the strongest mercury lines had appeared in the visible as well as in the ultra-violet part of the spectrum, and also the most characteristic thallium line, indicating a transmutation of lead into mercury and thallium.
"Since our experiments showed that a high current density is very favourable to this transformation, we used currents up to 60 A, but that seemed to be dangerous, because only by intensive air cooling could melting of the quartz-lamp be prevented.
"We thought it better, therefore, to change our method a little, by applying not a continuous electrical current but sparks of high current densities... While the lamp was kept oscillating by a mechanical arrangement... a current of high-density [60-100 A] was breaking and making... This method was very successful... After 9-1/4 hours' sparking all mercury lines, even the very weak ones, were present...
"This, however, does not yet prove the transmutation to be strong, as it is known that a relatively strong quantity of mercury can cause the spectrum of another element to disappear. But at all events our spectra show in a very convincing way the transmutation of lead into mercury..."
The researchers also conducted experiments with a nitrogen atmosphere at various pressures and a liquid dielectric (carbon disulfide) with 100kv/2 milliamperes for 12 hours. The mercury was chemically detected as the iodide. Similar results were obtained with 160 kv/10-20 milliamps. In six such experiments, 0.1-0.2 mg of mercury was recovered. The researchers suspected that the CS2 had contained a trace of some organic mercury compound. Positive results were still obtained, however, even after it had been thoroughly purified.
Smits offered this explanation for the transmutations:
"In the case of the transmutation of lead into mercury, the inactive isotopes having the atomic weights 206, 208 and 210, we may assume, for example, that the isotope 206 suffers a transmutation giving an isotope of mercury:
Pb - a = Hg
201 - 4 = 202
82 - 2 = 80
"But we may also assume that the other isotopes 208 and 210 undergo a transmutation. In that case we obtain:
Pb - 2a - 2q = Hg
208 - 4 = 202
82 - 2 = 80, and:
Pb - 2a - 2q = Hg
208 - 8 = 200
82 - 4 + 2 = 80
"In the case of the transmutation of lead into thallium we can assume, for example, the following process:
Pb - a - q = Tl
208 - 4 = 204
82 - 2 + 1 = 81
"We see that of the different transmutation possibilities, [the first] is most simple. Moreover, I suspected this process could be expected first, as lead is the end-product of the spontaneous radioactive transformations... The best method of learning the nature of the transmutation is to examine spectroscopically whether the process is accompanied by the formation of helium or hydrogen, and to determine the atomic weights of the heavier products...
"While using the old quartz-lead lamp, negative results were obtained only if the current strength was lower than 15 amperes, but now, with our new lamps... spectroscopically negative results were found even using 60 amperes. The lamp showed distinctly different properties in burning and sparking. This proves that the phenomena taking place in the quartz-lead lamp depend on influences unknown until now, so that transmutation in the quartz-lead lamp is not so easy to reproduce as we expected." (2)
In 1926, A.C. Davies and Frank Horton reported that they had been unsuccessful in their attempts to replicate the Smits-Karssen experiments. They offered these speculations:
"In the case of the transmutation of lead (82) into mercury (80), the change may occur either by the intermediate production of thallium by one of the processes already suggested [viz, "the entry of an electron into, or by the removal of a proton from, the nucleus of the mercury atom."], and the subsequent conversion of the thallium into mercury by a second similar process, or it can occur as a one-stage change by the ejection from the lead nucleus of either one doubly charged positive particle (presumably an a-particle) or two singly charged positive particles (presumably protons) simultaneously. If the process occurs by the intermediate production of thallium, one would expect to find evidence of a relatively large amount of thallium compared with the amount of mercury produced. Prof. Smits does not seem to have found such an effect, for he records stronger evidence of the production of mercury than of the production of thallium...
"When atoms are bombarded by electrons, it is possible that in a few instances an electron penetrates within the K shell of extra-nuclear electrons, though it is certainly surprising that this is possible in the circumstances of these experiments. When such a penetration does occur, the electron will be attracted towards the nucleus and may possibly be absorbed by it. Even so, in some cases the absorption of an electron by the nucleus may render the latter unstable and disruption may occur with the ejection of a proton and an electron, either separately or together, in which case the final chemical state of the disturbed atom will be the same as if the electron had been absorbed by the nucleus and a stable condition attained."
For some unknown reason, these explorations were not continued, and the issue disappeared from the scientific literature after 1928. This line of research remains open to exploration, since the questions it raised remain unanswered to this day.
1. Anonymous: Science-Supplement 62 (1602): 14 (11 Sept. 1925); "The Transmutation of Lead"; ibid., 63 (1623): 10 (5 Feb. 1926); "Transmutation of the Elements"
2. Davies, A.C., & Horton, Frank: Nature 117 (2935): 152 (30 Jan. 1926); "The Transmutation of Elements"
3. Nature 117 (2952): 758-760 (29 May 1926).
4. Smits, A., & Karssen, A.: Scientific American 133 (4): 230, 231 (Oct. 1925); "Cracking the Lead Atom"; ibid., 134 (2): 80, 81 (Feb. 1926); "The Transmutation of Elements"
5. Smits, A.: Nature 114 (2869): 609, 610 (25 Oct. 1924);"Transformations of Elements"; ibid., 117 (1931): 13-15 (2 Jan. 1926); ibid., 117 (1948): 620 (1 May 1926); "Transmutation of the Elements"; ibid., Nature 120(3022): 475, 476 (1 Oct. 1027); "Transmutation of Elements"
6. Thomassen, L.: Nature 119 (3005): 813 (4 June 1927); Transmutation of Elements"
7. Smits, A. & Karssen, A.: Die Naturwissenschaften 13 (32): 699 (7 August 1925); "Vorlaufige Mitteilung uber einen Zerfall des Bleiatoms"