British eclipse expedition to Christmas Island 1922

In 1922, two scientific expeditions made their way to Christmas Island. One was the British team led by Harold Spencer Jones, Chief Assistant, Royal Observatory, Greenwich. The other was a German-Dutch team led by Erwin Finlay-Freundlich, a German astronomer and physicist. Their aim was to test whether gravity (a large mass) could bend light. This was part of Einstein’s theory of relativity. To do this, they needed a full solar eclipse.

In a Sunday Times article, before he left on the expedition, Spencer Jones’ explained as follows:

… the main purpose of the expedition was to test one of the conclusions of Professor Einstein’s theory that rays of light passing near the sun, or any other massive body, are slightly bent, so that their path is no longer a straight line.

The only practical method is to photograph stars very near the sun and to compare those photographs with others of the same stars taken at night, when the sun is in another part of the sky.

Advantage of Eclipse.
Owing to the brilliance of the sun, the only possible opportunity of photographing stars very near the sun occurs at the time of a total solar eclipse, when the moon passes directly in front of the sun and obscures its light …

The Sunday Times (London, England), Sunday, December 31, 1922

So with four tons of bags, equipment and a large telescope, the British expedition travelled to Christmas Island. The expedition included Spencer Jones’ wife Gladys and you can read about her packing and expectations for the trip here.

In the following account Spencer Jones, described the setup and location of the telescope house at South Point.

… I was able to get the foundation prepared for the instrument. The site chosen was at the south end of the Island, A new quarry is just being opened there, and a railway has been constructed across the Island to bring the phosphate into the settlement. But for this railway, it would not have been possible for the instruments to have been erected there, as the Island is very densely covered with jungle. The telescope was erected just at the terminus of the railway, on a terrace which had been levelled in preparation for the erection of coolie lines. The pier for the telescope was built up from the solid limestone rock, so as to give a perfectly stable foundation, and was constructed of lumps of limestone, cemented together with concrete.

As the expedition was remaining for about six months on the Island, it was necessary to have a more substantial housing for the telescope than is customary on eclipse expeditions. A house had been designed by me before leaving home, and this was kindly erected for us by the Company. It consisted of a wooden framework covered with corrugated iron. The total area was 40 by 20 ft. The observatory proper had an area of 20 ft, square. To east and west of it were two rooms each of 20 by 10 ft., which served respectively as a living-room and a dark-room. The central portion of the roof was constructed to slide back in two halves to east and west, running on rails with double-flanged wheels over the two rooms previously mentioned. The roof was moved by means of cables wound twice round double-flanged wheels, and could be opened without difficulty by one person. The walls of the house were 12 ft. 6 in. high and afforded considerable protection against the wind, which in general was fairly strong.

The erection of the telescope proceeded without hitch. We were assisted by Chinese coolies who worked splendidly. The manner in which they lifted heavy parts weighing several hundredweights by man-handling, which we would ourselves have lifted with shear legs and tackle, was surprising. The only difficulty arose, before the observing house was completed, from the innate curiosity of the Chinese. They cannot resist the temptation to abstract any small piece of brass, etc., which they can detach. This they regard as a good ” joss.” The difficulty was overcome by warning them that the telescope took photographs, and if any of them were to touch it, it would take a photograph of them and they would be detected. Thereafter it was left severely alone.

H. Spencer Jones, ‘The British Eclipse Expedition to Christmas Island’, Science Progress, vol. 17, no. 68, 1923

And, was the expedition a success? Despite the many months of planning, the goal of photographing the stars near the sun during the eclipse was to be thwarted by something over which they had no control. Spencer Jones wrote:

The weather, which during the whole of our stay on the Island was generally unsettled, seemed at last to have set in fine. For several days preceding the eclipse, it would have been possible to have secured good observations. But, unfortunately, there was a change on the very day of the eclipse. I arose early, before dawn, and the sky was then completely covered with thick clouds. Somewhat later, heavy rain set in and our hopes fell to zero. But about 9 o’clock signs of improvement began to appear, the clouds gradually broke up, and half an hour later the sky was about the clearest which I have seen during the whole of my stay on the Island. The definition then was extremely good. But we had unfortunately still an hour and a half to wait for totality. The clouds began to gather again; first contact of the sun and the moon was well observed. Thereafter, it steadily grew more and more hopeless. There was a short break about twenty minutes before totality, but after that the sun was not seen again. The commencement of the total phase was dimly seen through cloud. One plate was exposed, first on the scale field and then on the sun. Owing to the cloud, it shows no stars, but a faint coronal ring is seen. But then even the glow of the corona through the clouds was lost, and the sun was not seen again until after the last contact, heavy rain following. So ended our hopes. Our disappointment it is impossible to describe. It seemed cruel to be sitting unable to do anything whilst the few valuable minutes for the coming of which so much preparation had been made were passing beyond recall.

… Before closing this account, mention must be made of the generous help afforded by the Christmas Island Phosphate Company. It was not possible to go to the Island without being dependent upon the Company in many ways, for supplies of labour, for materials of various sorts, for transport, etc. The Company conveyed the observers and the instruments in their steamer from Singapore to Christmas Island and back, supplied the labour required for unpacking, for erecting the telescope, for dismantling it after the eclipse and for repacking. They supplied both materials and labour required for the observing house. In many other ways we were dependent upon them, and although I felt at times that they were only able to meet our wishes at some inconvenience to their own work, everything possible was done to help us. All these services were given entirely free of charge to the expedition. Their kindness added to our regret that we were not able to return without something more to show for all that had been done for us. …

H. Spencer Jones, ‘The British Eclipse Expedition to Christmas Island’, Science Progress, vol. 17, no. 68, 1923

After Spencer Jones and his wife left Christmas Island they passed through Singapore on their way home. Whilst there he was interviewed and it was reported by the Straits Times. The wound of great disappointment in not being able to view the eclipse and surrounding stars at South Point, would have salt poured on it:

… Then referring to the location of the expedition on Christmas Island, Mr Spencer Jones said: “As ill luck would have it, on the north side of the island where the European settlement is, the eclipse was seen through a break in the clouds, but both parties had set up their instruments as far south on the island as possible because the duration of the totality was considerably greater there, being four minutes at the south as compared with two and a half at the Settlement,” and in this connection Mr. Spencer Jones added: “Those who observed the eclipse from the Settlement stated that it was a wonderful and a sublime sight. Several stars and planets were seen by the naked eye including Mercury, Venus and Jupiter.

… “It is disappointing to feel that after so much preparation and when everything promised so well, the instruments being in perfect adjustment, owing to clouds it was impossible to secure observations. But from a scientific point of view it may be hoped that the observations secured by the Lick observatory party at Wollal, will prove sufficiently good to settle the deduction from the Einstein theory.”

The Straits Times, 27 October 1922 “An interview with Mr Spencer Jones”

And as it turned out, the expedition to Wallal Downs Station, approximately 300 kilometres south of Broome, Western Australia, was a success. The skies were clear making for perfect viewing. Photographs that were taken, showed the deflection of starlight predicted by Einstein’s theory of relativity.

Harold Spencer Jones illustrious career would continue. The following year, in 1923, he was appointed His Majesty’s Astronomer at the Cape of Good Hope. He held this position until 1933 when he became the Astronomer Royal; a position he held until his retirement in 1955.

He was knighted in 1943 and received the KBE in 1955.

Explore Further

See Harold Spencer Jones’ Photographic Collection of the expedition at the Christmas Island Virtual Museum.