Doctor Wood. Modern Wizard of the Laboratory: The Story of an American Small Boy Who Became the Most Daring and Original Experimental Physicist of Our Day-but Never Grew Up

Chapter Sixteen. Tutankhamen’s gold

In the weird Wood guest book at East Hampton is a drawing made by Ambrose Lansing, curator of Egyptology at the Metropolitan Museum in New York. It is only slightly Egyptian. It is a burlesque of Wood’s own Animal Analogues, and is entitled “The Wood and the Woodchuck”. It depicts the woodchuck stealing lettuce from a cold frame not unlike a museum case, and the Wood similarly engaged in purloining the famous purple-gold sequins of King Tutankhamen from their case in the Cairo Museum.

“A joke’s a joke”, said Dr. Wood, “but after all we didn’t steal the purple sequins. You might say we abstracted them with the connivance of the Curator. You might even say, if it gives you more fun to put me always in the worst possible light, that we surreptitiously abstracted them, but — ”

“Did Curator Engelbach of the Cairo Museum say, or didn’t he”, I interrupted,” ‘For God’s sake keep it secret until you get out of the country, and on no account let Howard Carter know’?”

“I don’t think he said ‘for God’s sake,’” Dr. Wood replied, “and the only reason we didn’t want Carter to know was that we didn’t want to enrage him. After all, he was the one who had dug the stuff up. He fancied himself as a sort of sole executor and publicity agent for King Tut, and had never tolerated others cutting in on it”.

“All right”, I agreed, “you didn’t purloin them. I’ll let you tell in your own way in a minute exactly how you did obtain their — shall we call it? — temporary legitimate possession”.

Dr. Wood had become interested in the purple gold while on a visit to Egypt in 1931 with Mrs. Wood, traveling with Ambrose Lansing and his wife, Caroline, who were going to Cairo to superintend excavations at Lisht. It presented a mystery which Egyptologists, metallurgic chemists, and modern goldsmiths had been unable to solve. They hadn’t even been able to agree on the nature of the problem. A dispute had arisen since the discovery as to whether the purple gold was the product of an art known to King Tutankhamen’s goldsmith and subsequently lost for over three thousand years or was due to chemical changes resulting from long burial.

When Wood heard all this and saw the actual ornaments, all rose and red and purple, his scientific detective instincts were challenged, and I suspect also that his ubiquitous cat curiosity was involved in the subsequent events for more than a little. The problem, as a matter of fact, was a fascinating one for anybody. In the meantime Lansing had arranged with the authorities that the Woods were to receive all the privileges extended to archaeologists. Many of the smaller gold ornaments from the tomb were covered with a rose-purple film, quite unlike anything that had ever been observed on gold jewelry or coins either ancient or modern.

Wood leaned almost immediately to the theory that the purple sequins were the result of art rather than chemical accident. He noted the resemblance of the colors to those of certain gold films which he had prepared many years before when engaged in the study of the optical properties of very finely divided metallic granules, and felt sure that they had been produced at the time of manufacture, for on one of the king’s slippers small purple-gold rosettes and yellow-gold bars had been sewn in alternation, making a color pattern. There was, however, the possibility that the rosettes and bars had been made by different goldsmiths, with metal from different localities, one sample containing an impurity which slowly oxidized during the centuries, forming the purple film.

The objects on which the colored film appeared were small ornaments exclusively, sequins — some in the form of flowers from 1.5 to 2 cm. in diameter and others circular concave disks — which ornamented the ceremonial robe of the king, and a number of pendants and other head ornaments, on some of which the colors were extremely brilliant, ranging from a rich red to purple and violet.

Wood made a careful examination of the gold ornaments from other tombs displayed in the Cairo Museum, but found nothing resembling the Tutankhamen gold with the exception of a queen’s crown from the next dynasty, which was decorated with gold flowers showing the purple film in many places. This made it seem possible that the secret of the coloring process had been handed down from father to son, but had finally been lost.

So this all made a pretty problem. Said Wood to himself and to Lansing, and to their friend A. Lucas, who was British Chief Chemist for the Department of Antiquities in Egypt, “I believe I could rediscover the secret — if I could get hold of some of the ornaments”.

Lucas was for it, but it wasn’t going to be easy. Howard Carter wasn’t going to be eager to lend them to an itinerant American professor who wasn’t even an Egyptologist to play with. And they were all locked up and screwed down in their museum case in Cairo.

“The only thing we can do”, said Lucas, “is to get the consent of the Curator”.

When the plot was disclosed to Curator Engelbach, he agreed in the interest of science, but concurred emphatically — with or without the “for God’s sake” — when Lucas said, “We’ll have to keep this secret. No sense ever to let Howard Carter know — unless you succeed with the experiments”.

MOONSHINE: One of the photographs Wood faked for illustrating The Moon-Maker, the pseudo-scientific “thriller” on which he and Arthur Train collaborated. The “flying ring” is taking off from the surface of the moon.

MAJOR WOOD: Wood is testing the “flash telescope,” which he originally constructed from an old piece of stovepipe and other discarded parts, and which was the first device offered by the Science and Research Division actually put into production for overseas use in the A.E.F.

It wasn’t merely Howard Carter’s private vanity. If the government learned that Wood was trying to take out any of the sequins, he would be searched at the customs house until they were recovered, and Carter would raise public hell — not about “purloining”, but about the proposed unauthorized investigation.

What they did next, I’m letting Wood tell in his own way.

After Lucas had persuaded the Curator, the three of us went to the museum hall accompanied by two uniformed guards who had two separate sets of keys. While popeyed tourists stood around, they opened six separate padlocks and were then compelled to take out about a dozen screws which held down the glass. When the case was opened the Curator whispered to me to pick out what I wanted. I began picking sequins, with continual side glances at the Curator, watching for raised eyebrows. At the eighth, I saw symptoms and said, “Thank you very much, these will suffice”. I had been picking them out with my right hand and holding them in my left. The Curator said sternly and aloud, doubtless to reassure the pop- eyed tourists or perhaps his own guards, “Now give them to me”. He was a sleight-of-hand artist and slipped them back to me before we left the museum.

The archconspirator had scarcely returned to his hotel when a note was brought to him — from Howard Carter! It turned out, however, as coincidences happily often do, to be merely an invitation to visit the great Egyptologist in his laboratory headquarters in one of the old tombs, in the Valley of the Kings. Wood bearded the lion, and says, “I felt like the boy who’d almost been caught stealing the apples… but at the same time felt a temptation to tell him I had the sequins”.

How Wood found the lost secret of the purple gold, beginning there in Cairo with his wife’s nail polish and ending in the Johns Hopkins laboratories with a series of experiments as strange as any you’ll find in fictional scientific detection, is today a brilliant page in the history of Egyptology and of chemical-physical research. He not only rediscovered the ancient method and proved that the coloring was no accident due to chemical changes, burial, and time, but succeeded in reproducing, by a finally simple technique such as might easily have been known to goldsmiths three thousand years ago, all the gorgeous colors, ranging from roseate dawn pink through rich red, purple, and violet. Here in his own clear words is the story step by step.

My first problem (he explains) was to ascertain whether the colors were simple “interference” effects of thin films (soap-bubble colors) or due to some “resonance” action of minute particles covering the gold surface. This was purely a problem in physical optics. Since interference requires the cooperation of two streams of light reflected from the opposed surfaces of a thin film, the first step in the study appeared to be to destroy the reflection from the outer surface by covering it with a transparent varnish. This experiment I tried in Cairo, employing my wife’s nail polish, the only available material of the desired nature. The color was not destroyed, as it would have been in the case of an interference color, and after the celluloid had become dry, I found that it could be peeled off, carrying the film with it and leaving the underlying gold bright yellow. The film, however, now showed no color, either by transmitted or reflected light. This was as far as I could go at the time, but on my return to my laboratory in Baltimore I deposited metallic gold on the back of the film by cathodic sputtering and found that the purple reflection was restored. These two experiments appeared to show conclusively that we were dealing with something more complicated than simple thin film interference.

The next step was to ascertain the nature of the film. This was done by placing a bit of the celluloid film carrying the film from the sequin between two electrodes of pure gold and photographing the spectrum of a very brief spark discharge. Iron lines were found in the spectrum. A purple sequin was then hung on a very fine glass thread between the poles of an electromagnet, and when the current was turned on, it was drawn to one of the pole pieces. One of the yellow bars from the slipper was thrown out of the magnetic field, showing that it contained no iron, while one of the small purple rosettes was attracted. These two specimens were returned to the museum, as they were needed for the reconstruction of the slipper. They had served their purpose, however, in showing that the purple rosettes contained iron, while the yellow bars were free from it. It was now necessary to find out how the film, presumably iron oxide, had been formed, and whether it was intentionally produced or was an accidental patina resulting from time.

I prepared an alloy of pure gold and a very small fraction of 1 per cent of iron, hammered the bead into the form of a disk, and heated it over a very minute flame. At a temperature a little below a dull red heat a beautiful purple film formed, matching the color of the sequins almost exactly. As I could not ascertain the effect of three thousand years of exposure to the air on one of my alloy plates, I was obliged to look for other evidence that the color was produced by the heat process. I removed the purple film from a small piece of one of the sequins by nitromuriatic acid and examined the gold with the microscope. The surface had been etched by the acid and showed a very marked crystalline structure. A similar treatment of one of my replicas revealed the same crystalline structure, which was not shown by specimens which had not been heated to a high temperature after the hammering process. Pure gold rolled into a thin plate between steel rollers shows only very minute crystals when etched, but if heated shows crystals of exactly the same size and character as those found in the Egyptian sequins. This was proof number one that the sequins had been heated after their manufacture.

Proof number two came as a result of an investigation of another surface characteristic of the sequins, the invariable, presence of minute metal globules of gold which stood up in high relief on both sides of the sequins. Obviously these must have been formed after the ornaments had been hammered or rolled into shape, and one or two had the form of minute mushroom buds, a globule supported on a short stem. This suggested that they had been exuded or excreted by the metal, by a process similar to that which occurs when a silver bead is heated on charcoal by the blowpipe flame, the phenomenon referred to as the “spitting of silver”. It results from the liberation of dissolved gas at the moment of solidification of the globule. I was unable to find any allusion to a similar performance by gold and for some time was unable to produce the globules on my replicas.

The solution of the problem came in a rather fantastic way. I had made spark spectra of the purple sequins and found practically no lines save those of gold and iron, the latter being quite strong. A more careful scrutiny revealed a few very faint lines which could not be attributed to either metal, and two of these I attributed to arsenic. I next heated a small fragment of one of the sequins in a small tube of fused quartz to a temperature considerably above the melting-point of the gold in a very slow stream of hydrogen, and found a deposit on the wall of the tube beyond the heated portion, a yellow and a black ring, the latter on the side away from the gold. I therefore suspected the presence of sulphur and arsenic, and native sulphide of arsenic (the yellow pigment orpiment) was in fact imported into Egypt during the Eighteenth Dynasty and used in tomb decorations. This suggested that the royal goldsmith had perhaps tried the experiment of fusing gold with the yellow pigment in the hope of improving the color or of getting more gold. I wrote to Mr. Lucas asking for a few minute scrapings of this material, and he sent me some small lumps that had been found in a cloth bag in the tomb of Tutankhamen. I fused a small speck of this substance wrapped up in a pellet of thin gold plate, and as the fused globule solidified it “spit” out a small globule exactly as silver does. But a thin plate hammered from this globule and then heated showed no trace of further “spitting”.

It was now obvious that the gold and orpiment would have to be melted together and solidified under pressure to obtain a specimen that would “spit” after being fashioned into a plate by hammering or rolling. I accordingly heated the two in a small sealed tube of fused quartz, melting the gold down to a round globule. Some of the sulphur and arsenic was liberated as vapor under pressure and glowed bright red in the non- luminous tube (for quartz radiates practically no light even at very high temperatures). After cooling, the tube was opened and a plate hammered and rolled from the globule. When heated to a dull red heat the plate grew a marvelous crop of metal mushrooms.

This suggested that the necessary pressure required for keeping sufficient arsenic and sulphur in the gold to produce “spitting” may have resulted from the fusion of a considerable mass in a crucible, for we know from the bas-reliefs at Saqqara that the Egyptians used furnaces operated by air blasts from human lungs. But there was another and more probable alternative, namely, that the sequins had been fashioned from native gold nuggets which contained a trace of iron as an impurity. These, having been originally formed deep in the earth and under pressure, might easily contain sulphides, arsenates, or similar gas-producing compounds in sufficient quantity to produce the small amount of “spitting” shown by the sequins.

A number of plates were therefore hammered from small nuggets of native gold from various localities, and most of them showed the excretion of minute globules when heated to a dull red. None of these showed any trace of the purple film, however, and I wrote to Mr. Lucas asking for specimens of native Egyptian gold. The single specimen which he sent gave globules, but no purple film. This gold was, however, embedded in quartz, and unsuitable for immediate fashioning into ornaments. Alluvial gold may very probably have been imported from Abyssinia, where the placer deposits are still worked, and it would be extremely interesting to see whether the purple color would appear on plates hammered from nuggets from this or from other possible sources of ancient Egyptian gold. On the whole, I favored the theory that the sequins were hammered from nuggets of native gold containing a trace of iron, one of which was accidentally dropped into a fire, or perhaps heated for annealing, with the resulting discovery of the purple color.

A complete survey of the gold deposits of Abyssinia was under way in 1932, and I wrote to Mr. E. A. Colson, president of the Bank of Addis Ababa, asking for small nuggets from different localities. These he mailed to me from time to time, and all yielded globules, but none the purple film. I had explained to him that should a sample ever be found containing iron it might prove to be a valuable clue in locating the rich deposits worked in ancient times. Mussolini, however, stopped the game just as it was getting under way, and Mr. Colson died shortly after.

Some of the sequins made by Dr. Wood are now in the Cairo Museum along with the originals. His solution of the mystery is embalmed in the British Journal of Egyptian Archaeology and in the archives of the Egypt Exploration Society.