Eyewitness accounts

The events during the start and the first part of the flight of Örnen are well documented (Andrée et al., Reference Andrée, Strindberg and Frænkel1930; Ekholm & Svedenborg, Reference Ekholm and Svedenborg1922; Sundman, Reference Sundman1968). After waiting for stable southerly winds at Danskøya for nearly two weeks, the morning of 11 July 1897, finally provided favourable conditions for the Andrée expedition to attempt a flight to the North Pole; there was a moderate breeze from south-southwest (Strindberg, Reference Strindberg, Andrée, Strindberg and Frænkel1897b). Following thorough discussions among Reference Andrée, Strindberg and FrænkelAndrée, Strindberg and Frænkel, as well as with the expedition support crew, the decision was made. They penned their final letters, and at 1.41 p.m., they boarded the gondola, bidding farewell at 1.43 p.m. The mooring lines securing the balloon in the balloon house were severed, and at 1.46 p.m., the hydrogen balloon Örnen, which had never been test flown, ascended (all times in UTC, based on Strindberg’s real-time diary entries). Critical events unfolded during the next few minutes. The intention was to achieve some level of manoeuvrability for Örnen using guide ropes, which were intended to slide behind the balloon on the ice, and a sail. However, upon launch, the lower sections of all three guide ropes were lost, resulting in Örnen becoming an uncontrollable free-flying balloon. The balloon suddenly lost altitude and briefly dipped into the sea, prompting Reference Andrée, Strindberg and FrænkelAndrée, Strindberg and Frænkel to jettison eight bags of ballast to regain elevation.

At 1.56 p.m., 10 min after departure, the balloon flew over the flat headland at the eastern part of Amsterdamøya, where Strindberg had intended to drop the tin containing the letter to Anna Charlier, on the expected (given the wind) roughly north-northeast trajectory. Eighteen minutes later, at 2.14 p.m., apparently having increased speed, the balloon was flying directly west of Fuglesongen at an altitude of about 600 m. In the following moments, Örnen veered in over Fuglesongen and temporarily vanished from view from Danskøya, both becoming obscured by clouds and by descending below the highest point of Fuglesongen.

Several members of the expedition support crew who witnessed the departure of Örnen from Danskøya documented their experiences and memories from the event. Below is a review over these narratives, with respect to Örnen’s passage of Fuglesongen and its surroundings.

Lieutenant G. R. Celsing (Reference Celsing1897, pp. 233–234) wrote in the scientific journal Ymer: “The balloon finally disappeared behind Vogelsang, only to reappear for a moment east of this island, after which it again moved north and disappeared.” [In Swedish: “Ballongen försvann slutligen bakom Vogelsang för att åter visa sig ett ögonblick öster om denna ö, hvarefter den åter drog sig åt norr och försvann.”].

Lieutenant G. V. E. Svedenborg, the designated alternate crew member in case Andrée, Strindberg or Frænkel became unable to participate in the balloon flight, described his observations from the launch in an article in the Swedish newspaper Aftonbladet, on 27 July 1897 (Svedenborg, Reference Svedenborg1897): “We saw the balloon, after just over half an hour, go behind Fogelsang. In the lee of this island, it seems to have moved slightly eastward, but then appeared to resume its previous direction.” [In Swedish: “Vi sågo ballongen efter något öfver en half timme gå bakom Fogelsang. I lä om denna ö tycks den ha dragit sig något åt öster, men syntes sedan återtaga sin förra riktning.”]. It is worth noting that Svedenborg also published a more extensive piece about the Andrée expedition 25 years later (Ekholm & Svedenborg, Reference Ekholm and Svedenborg1922) but did not provide any details about the passage of Fuglesongen at that time.

J. Stadling, a correspondent for the newspaper Aftonbladet with the assignment to report from the expedition, published an article covering the launch of the balloon, on 23 July 1897 (Stadling, Reference Stadling1897): “Here, Örnen made a new turn eastward over the northern tip of the island Fogelsang, whereupon it disappeared into a cloud. After a while, it became visible again in a north-northeast direction between the islands Fogelsang and Cloven Cliff, whereupon it once again veered westward and finally disappeared from our sight approximately one hour after its ascent.” [In Swedish: “Här gjorde Örnen en ny svängning mot öster öfver ön Fogelsangs norra udde, hvarpå den försvann i ett moln. Om en stund blef den åter synlig i nordnordostlig riktning mellan öarna Fogelsang och Cloven Cliff, hvarvid den ånyo svängde mot vester och slutligen försvann ur vår åsyn cirka en timmes tid efter dess uppstigande.”]. Thus, Stadling’s narrative clearly indicates that the balloon zigzagged across the area, rather than following the straight course depicted in Figure 1. It is worth noting that Stadling also published a longer article about the Andrée expedition in 1898 in The Century Illustrated Monthly Magazine (Stadling, Reference Stadling1898), but he also did not reveal any further information about the passage of Fuglesongen in that piece.

A. Stake, the engineer responsible for the hydrogen production in Danskøya, recorded in his diary, which remained unpublished until 2022 (Stake, Reference Stake2022, p. 131): “… then proceeded in a straight line between Pike’s Point [a landmark on Danskøya close to the point where the balloon was launched] and the northwestern corner of Vogelsang, over which it ascended and disappeared among the clouds. We observed it for about 1 h.” [In Swedish: “… gick så i rak linje mellan Pikes udde och nordvästra hörnet av Vogelsang över vilken den höjde sig och försvann bland molnen. Vi sågo den ca 1 timme.”]

A. Machuron, a mechanic and representative for the balloon manufacturer, H. Lachambre, documented the passage of Fuglesongen in his book about the expedition (Lachambre & Machuron, Reference Lachambre and Machuron1898, p. 302–304): “We see it clear the top of the hill, and stand out clearly for a few minutes against the blue sky, and then slowly disappear from our view behind the hill. Scattered along the shore, we stand motionless, with full hearts and anxious eyes, gazing at the silent horizon. For one moment then, between two hills we perceive a grey speck over the sea, very, very far away, and then it finally disappears.”

Dr. G. Violet, a correspondent for the German newspaper Lokal-Anzeiger, conveyed details about the expedition in a telegram, reproduced in the Swedish newspaper Svenska Dagbladet on 20 July 1897 (Violet, Reference Violet1897): “… it looked as though it was being pressed against the cliffs at Vogelsang, but with the aid of binoculars, we could see how it hovered a few meters above them and now completely free, continued northward. At exactly 3 o’clock, the balloon disappeared at the horizon.” [In Swedish: “…. Det såg ut, som om den trycktes mot klipporna vid Fågelsång, men med beväpnade ögon kunde vi se, hur den sväfvade några meter öfver dem och nu alldeles fri fortsatte mot norr. På slaget 3 försvann ballongen vid horisonten.”]

Yet another eyewitness, supposedly an officer on Svensksund according to Ekholm and Svedenborg (Reference Ekholm and Svedenborg1922) and apparently also a correspondent for the newspaper Stockholms Dagblad, wrote anonymously an article about the departure in the paper (Då Andrée steg upp, 1897), but with no further details about the passage of Fuglesongen. (Most likely, Celsing was this anonymous writer.)

Among the other main members of the expedition support crew who witnessed the departure, Captain C. A. Ehrensvärd did not produce any personal writings about the event, yet he pointed out in an interview (Andree: Svensksunds återkomst, 1897) that Violet’s prior account regarding the departure was inaccurate. Similarly, Lieutenant C. G. Norselius, having not authored any personal documents relating to the departure, highlighted inaccuracies regarding Violet’s narrative in an interview (Svensksund åter hemma, 1897). The surgeon aboard Svensksund, Dr. Lembke, while not having published any personal accounts, was also interviewed (Svensksund åter hemma, 1897) but did not specifically address any details of the departure.

As shown, the eyewitnesses at the launch site in Danskøya did not perfectly agree on the details of how the passage of Fuglesongen occurred. However, in a summary of the course of events during the departure of Örnen, Ekholm & Svedenborg (Reference Ekholm and Svedenborg1922) emphasised that Celsing’s, Svedenborg’s and Stadling’s accounts were portrayed in a consistent and believable manner, but that neither the account by Violet nor the narrative by Machuron were reliable, since they differed in several aspects from the Swedish authors’ relatively uniform description. Consequently, Ekholm relied primarily on Celsing’s account in his chronicle. It should be noted that this analysis by Ekholm was conducted eight years before the final camp on Kvitøya was discovered and, thus, was not in any way biased from Strindberg’s diary notes.

Sundman (Reference Sundman1968), who compiled an otherwise magnificent collection of source material about the Andrée expedition, relied solely on Celsing (Reference Celsing1897) in his description of Örnen’s passage over Fuglesongen and its surroundings. Thus, the consensus among scholars seems to be that the most reliable eyewitness accounts are Celsing’s, Svedenborg’s and Stadling’s. Stake’s diary, recently published, also supports these accounts.

Strindberg’s diary notes

Several diaries and notebooks were discovered scattered at the final campsite of the Andrée expedition on Kvitøya in 1930. Among these findings was Nils Strindberg’s annotated almanac from 1897, located at the tent site. In this almanac, comprising 142 pages in total, Strindberg made his diary entries. The notes in the almanac have been analysed by the authors of this paper, with particular attention given to the entries spanning pages 57–58 (see Fig. 4). These pages cover Strindberg’s notes on the events surrounding the balloon launch and the initial 77 min of the flight, including the notation about dropping the tin at Fuglesongen. Notably, the pre-printed dates on the spreads do not correspond to the dates of Strindberg’s handwritten entries.

Figure 4.

Nils Strindberg’s handwritten diary notes from the first 77 minutes of the balloon flight. Courtesy of The Swedish Society for Anthropology and Geography.

Strindberg’s diary notes were already published in 1930 (Andrée et al, Reference Andrée, Strindberg and Frænkel1930), but the re-analysis in this paper has revealed some previously overlooked details. By studying all handwritten entries within the entire almanac, a discernible pattern emerges: it becomes evident that Strindberg begins almost every new paragraph with an indentation, followed by text lines starting at the far-left margin. This structural understanding allows for the identification of which lines of text were written in sequence: those beginning at the far-left margin are consequently linked to a preceding, indented line. In addition, some previous interpretations of the diary notes made upon their initial publication (Andrée et al., Reference Andrée, Strindberg and Frænkel1930) were found to be incorrect. For example, there is, in fact, no period on line 9 after Strindberg’s note about forming fogs, which alters the understanding of lines 9–10. Using these insights, the authors of this paper have also conducted a new translation of the diary notes into English.

Tables 1–4 present the translated version and analysis of the content of pages 57–58 in Strindberg’s diary. The complete Swedish version, which notes inaccuracies in previous interpretations, is included as an appendix. Note that Strindberg’s chronometer, known as Kullenberg 5566, was initially not accurately set, running 9 min ahead of the correct time. He only became aware of this problem 64 min post-launch, as indicated by a notation on the right page, line 25. Therefore, both Strindberg’s indicated time and the corrected time are referenced in Tables 1–4.

Table 1.

Nils Strindberg’s handwritten diary notes from the departure

Table 2.

Nils Strindberg’s handwritten diary notes from the passage of the Fuglesongen area

Table 3.

Nils Strindberg’s handwritten diary notes from the continuing flight, still within sight from Danskøya

Table 4.

Nils Strindberg’s handwritten diary notes from the continuing flight, no longer within sight from Danskøya

The next step is to examine Strindberg’s account of his observations with regard to the passage over the Fuglesongen area. In lines 7–8, Strindberg describes his observations of the northernmost part of Fuglesongen from an altitude of 600 m, which corresponds to point 1 on Celsing’s sketch (“h = 600 m North Cape 2 27”). At this point, the elevation of the island is about 300 m. Thus, if the tin had dropped there, it would have traversed through the air for approximately 300 m. Given the average speed of the balloon, the current wind speed can be estimated to somewhere around 10 m/s, indicating that the tin may not have landed where Strindberg had intended. When the tin left Strindberg’s hand, it had the same horizontal velocity as the balloon, and the wind likely supported its velocity rather than slowing it due to air friction. Thus, the tin could even have landed in the water without Strindberg noticing it from a relatively large distance.

In the following paragraph (lines 9–10), Strindberg mentions the formation of fog (“Fogs are forming 2.29”), corroborating eyewitness accounts of the balloon disappearing into clouds at this time. In line 11, Strindberg notes: “Quiet and still.” This is noteworthy, given that the act of documenting this particular observation here implies that he has not previously experienced the journey as quiet and still. Given the aerostatic nature of Örnen, a hydrogen balloon flying freely with the speed of the wind, the gondola conditions could have been completely calm, provided sufficient height. Due to the friction of air against the surface, the airflow near the surface is always turbulent. This is characterised by rapid fluctuations in the wind in all three dimensions, much faster than the inertia of the balloon would allow it to adjust. The intensity of the turbulence typically decays with height up to, here, typically a few hundred metres. Apart from the tumultuous events during and immediately after the launch, when the balloon was close to the surface, the journey ought to have been quiet and still all the time up to this point. However, the only external circumstance that was documented to have changed at this time, which may have prompted him to make the note, is the formation of fog. It is easy to imagine that Strindberg in this situation became more aware of the stillness when he was deprived of his visual impressions and had to rely solely on hearing and the sensation of movement. If the fog was dense around Örnen with a loss of visibility it is possible that Strindberg also lost the ability to orient himself. This is further supported by the fact that Strindberg was neither making any notes at this time about the balloon significantly losing altitude nor was he noting that the course was simultaneously deviating significantly to the east. When visibility cleared again, it is possible that the balloon was over Klovningen, the island closest in proximity. This is about 2 km further east, and at an approximate speed of 10 m/s, this would have taken about 3 min. This opens up the possibility that the tin may have been dropped there, under the mistaken belief that they were still situated above Fuglesongen.

Should the tin indeed have been dropped at Fuglesongen, this event would have occurred at a time between lines 7 and 13 in the diary notes (i.e. between 2.18 p.m. and 2.24 p.m., corrected time). It is worth noting that Strindberg refrained from documenting this important event in real-time, despite having the opportunity, as it was calm and quiet. Instead, he prioritised calculating and documenting the balloon’s average speed at lines 12–13, noted as “Speed average 0.57 km/minute.” Could this discrepancy imply that the tin was not dropped during these minutes, possibly due to poor visibility, preventing Strindberg from seeing the ground?

It was not until approximately 30 min after the tin drop that Strindberg made a note of it, as seen in lines 27–29: “My tin with farewell words to Anna was thrown at Vogelsang.” This is one of the few sections on the spread written in past tense. It should also be noted that it is written in passive voice. Could this suggest that either Andrée or Frænkel threw the tin, while Strindberg was making navigational computations, perhaps doing so with less attention to recording which island it was dropped on?

Analysis

The purpose of this section is to analyse the passage over Fuglesongen and its surroundings, based on comparisons of Strindberg’s notes and the eyewitness accounts, in order to deduce a detailed timeline of the passage thereby providing a deeper understanding of the likelihood of either Fuglesongen or Klovningen being the actual target for Strindberg’s tin.

First, Örnen’s altitude when they had just swung in over Fuglesongen at 2.18 p.m. was, according to Strindberg, approximately 600 m. This estimation seems relatively reliable; Celsing (Reference Celsing1897) estimated the altitude before the crossing of Fuglesongen to be 700 m, Stadling (Reference Stadling1897) mentioned 800 m and Svedenborg (Reference Svedenborg1897) 500 m. However, we know that the balloon must have begun to descend rapidly once it had flown in over Fuglesongen, even though Strindberg never mentioned this explicitly in his notes since both Celsing (Reference Celsing1897) and Svedenborg (Reference Svedenborg1897) agreed that the balloon disappeared behind Fuglesongen, and the highest peak on the island—Rotgangsfjellet—is only 387 m high. Lachambre and Machuron (Reference Lachambre and Machuron1898) also mentioned that the balloon disappeared behind Fuglesongen. Furthermore, at 2.24 p.m., Strindberg wrote that a guide rope touched the water. The remains of the longest guide rope, after its lower part had been lost at departure, was 105 m (Ekholm & Svedenborg, Reference Ekholm and Svedenborg1922); thus, the altitude of the balloon at this point was probably about 100 m. Thus, they must have descended approximately 500 m in 6 min, and once again, the balloon was positioned over water, not land, at that time. It is remarkable that Strindberg never mentioned this rapid descent in his notes, given that he had time to write that he perceived the journey as still and quiet during these minutes. Could the reason be that he did not realise the balloon was descending so rapidly due to the lack of visibility from the fog he had just mentioned?

Second, Stadling (Reference Stadling1897) mentioned that Örnen disappeared into a cloud rather than becoming obscured from view behind Fuglesongen itself. Neither Celsing (Reference Celsing1897) nor Svedenborg (Reference Svedenborg1897) included the cloud in their narratives, but Stake also mentioned that the balloon disappeared among clouds. The cloud(s) apparently match Strindberg’s observation at 2.20 p.m. in the balloon that fogs were forming.

Third, it seems clear that they swung in over Fuglesongen somewhere at the northern part of the island. Stadling (Reference Stadling1897) wrote that the balloon made a new turn eastwards over the northern tip and Stake (Reference Stake2022) mentioned that it flew to the northwestern corner of Fuglesongen. Strindberg noted at 2.18 p.m. in connection with an estimated altitude of 600 m that he could see the northern tip of the island. However, the island is small, and without clouds at an altitude of 600 m, one can easily see the northern tip of the island even from the southern tip. Thus, Strindberg’s note does not necessarily mean that they flew over or even close to the northern tip.

Moreover, the turn eastwards over Fuglesongen must have been substantially sharper than what the flight path in Figure 1 suggests; otherwise, the balloon could not have been seen to the east of Fuglesongen by eyewitnesses on Danskøya, which Celsing (Reference Celsing1897), Svedenborg (Reference Svedenborg1897) and Stadling (Reference Stadling1897) all agree that they could. In addition, Svedenborg (Reference Svedenborg1897) mentioned explicitly that the balloon seemed to have veered eastwards over Fuglesongen, and Stadling (Reference Stadling1897) stated that it was visible between Fuglesongen and Klovningen. Finally, point 2 in Celsing’s sketch (see Fig. 2) shows that the line along which he saw the balloon when it became visible after having crossed Fuglesongen crosses Klovningen. Thus, the balloon must at this point have been located either at a much more easterly flight path than what Figure 1 indicates, either north of Klovningen or over Klovningen itself. A more realistic path is indicated in Figure 5.

Figure 5.

A possible flight path across the Fuglesongen and Klovningen area which does not contradict the observation by Celsing. Created by the authors. Map from Norwegian Polar Institute.

Since Örnen essentially became a free-flying balloon—having lost the lower sections of the guide ropes—the winds dictated its course. We know that the balloon became embedded in a cloud when it reached Fuglesongen and then experienced a rapid descent of 500 m in 6 min. The rapid descent and changes in the path indicate significant shifts in the local winds.

There is no way to reconstruct the winds as they were on the day of the expedition’s departure. Today—unlike at that earlier time—it is well understood that both wind speed and direction vary with height within the so-called boundary layer, the lowest portion of the atmosphere where the flow always becomes turbulent due to its interaction with the solid surface. First, wind speed increases with height, approaching a free atmosphere velocity at the top of the boundary layer, at the region of Andree’s departure likely only a few hundred metres. But the wind also systematically changes direction with height. It was in fact Fritjof Nansen, who during his Fram expedition first observed how sea ice tended to drift to “the right of the wind” (when standing with the wind in the back). During a visit to Stockholm, he mentioned this to the then student Vagn Walfrid Ekman who derived the theory behind the so-called Ekman spiral for the ocean currents (Holton, Reference Holton2004, pp. 127–129); it became his PhD thesis in 1902 (Ekman, Reference Ekman1902), and it has later been confirmed that the same applies to the lower atmosphere. According to this, the wind direction near the surface would, under the influence of the Earth’s rotation, on the northern hemisphere be lower than that in the so-called free troposphere above the turbulent layer. As the wind speed must be zero at the surface, the wind speed would simultaneously increase with height up to the free atmosphere, where the airflow would be smooth, steady, and not turbulent (Holton, Reference Holton2004, pp. 115–116). The simultaneously increasing and turning wind with height is what today’s hot air balloonists, who can regulate their altitude, use to somewhat steer their vehicles. Hence, assuming everything else was horizontally homogeneous and stationary if the airflow close to the surface indicated a southerly flow, it could well have been southwesterly and significantly stronger a few hundred metres above the surface.

Furthermore, complex orography such as mountainous islands may affect the airflow strongly, especially when the lowest atmosphere is negatively buoyant (stably stratified), as it would be with warm air flowing over a colder Arctic surface; the documented southerly airflow may be indicative of such conditions. Depending on both terrain height and the depth of the turbulent atmospheric boundary layer, this can lead to dramatic alterations in both wind direction and speed (Holton, Reference Holton2004, pp. 284–289). If a shallow boundary layer, which is capped by a temperature inversion where the temperature increases with height, is located at a height comparable to the highest terrain, this can have dramatic effects on the flow. The boundary layer, below the inversion, accelerates and diverges to flow around the sides of the island, and the wind direction can therefore change dramatically over short distances in an archipelago. The air aloft, inside the inversion and higher, may instead form a single wave-like feature, where the air rapidly accelerates over and descends on the lee side of the island. A balloon trapped in the inversion at a few hundred metres would experience an acceleration, followed by a loss in altitude. Some distance downstream, a so-called hydraulic jump, may appear, where the boundary layer suddenly deepens, and the flow decelerates back to its background speed. A very similar analogy can easily be found in a stream where water is flowing over a rock that is just barely submerged.

In addition to the obvious effects on visibility, the documented fog may complicate the situation. The fog is likely to be more turbulent, and liquid water may deposit on the balloon. This situation worsens if the temperature in the fog is slightly below freezing (temperature typically decreases by approximately 1° C per 100 m), so-called super-cooled conditions, as fog droplets would freeze into ice on the balloon surface immediately. The added weight of water and ice would impact the balloon’s altitude.

In summary, the effects of orography on the larger Svalbard scale and the Ekman spiral make it quite possible that the free flow at some height west of Svalbard was more westerly than southerly, but terrain blocking at low altitude west of the islands led to the observed south-southwesterly flow. As this flow interacts with the very northwesternmost islets of Svalbard, this can lead to both intense changes in wind speed and direction and fog formation. Therefore, it is plausible to infer that the suggested changes in path and altitude may have been brought about by local topography in combination with atmospheric static stability. Consequently, the distinct eastward deviation in the balloon’s flight path over Fuglesongen while obscured from the observers on Danskøya is plausible.