A vague project for research of the marine fauna of the Malayan Archipelago was launched in May 1896. At a meeting on 19 September of the same year Weber declared himself willing to accept the leadership of an expedition with the object of the study of the marine flora and fauna of the archipelago, especially of its deep basins (Sluiter, 1897; Weber, 1897). This proposition was accepted. In April 1898 Weber sent an explanatory statement to the Minister of Colonial Affairs in which he still had to plead in favour of the availability of a steamship rather than a little schooner (Weber, 1898a). This memorandum was accompanied by a map (Fig. 3) in which the projected track of the expedition was indicated. The track could be executed in three stages, each of about three months - provided a steamship was used. The reply was favourable, as the Dutch East Indian Government put the steamship Siboga at Weber's disposal and designated him to be leader of the expedition, according to a decree of 21 May 1898 (Weber, 1902: 7).
The Siboga (Fig. 4)
was a brand-new gunboat with two propellers,
destined for military purposes in the Dutch East Indies. She had been put on
the stocks in Amsterdam on 14 August 1897 and launched on 28 April 1898. The
ship was about 170 feet long (50.6 m) and of 810 tons displacement (Tydeman,
1902b: 1; for comparison: the Willem Barents was 75 feet long, the
Beagle 90 feet, and the Challenger 200 feet - the latter of
2300 tons displacement; cf. Thompson, 1938: 348, Moorehead, 1969: 38, and
Linklater, 1972: 15, respectively). The Siboga had an engine of about
1400 horse-power (for comparison, the Challenger had an engine of about
1200 horse-power, but was still essentially a sailing-ship).
It was extremely fortunate that the Siboga was nearly seaworthy when
the decision came to make her available for this expedition, because it was
still possible to introduce certain changes. For instance, two sounding
machines with enormous steam-driven winches were installed on the bridge
instead of guns (Tydeman, 1902b). Of course, a laboratory had to be installed
as well. On Fig. 5
we see part of the dredging apparatus and the entrance to
the laboratory. On Fig. 6 we see the scientific staff working in the lab
(except Mrs. Weber and the physician Dr. A. H. Schmidt): Dr. J. Versluys, 1st
assistant (later Professor in Vienna), Professor Max Weber, leader of the
expedition, Mr. J. W. Huysmans, artist, and Mr. H. F. Nierstrasz, 2nd assistant
(later Professor in Utrecht).
In his introduction and description of the Siboga Expedition, Weber (1902) acknowledges the indefatigable help and wise advice of Mr. J. van der Struyff who, as engineer of the Dutch Navy, was charged with the construction of the ship. He even accompanied Weber to Hamburg, in order to see the installations of the Valdivia, of which Professor Carl Chun showed them all the instruments. Weber's narrative, the first monograph in the series Siboga Expeditie , published in January 1902, is written in French and is therefore accessible to most foreign readers. However, the popular account by Mrs. Weber, of which the first edition appeared in 1904 in a magnificent Jugendstil binding, is less accessible; it was only translated into German (Weber-van Bosse,1905). She relates some anecdotes that cannot be found anywhere else. We also read Weber's diary of the expedition, written in six notebooks that were rediscovered about a decade ago in the attic of the Zoological Museum in Amsterdam, together with the original glass negatives of the photographs made during the expedition, and all his correspondence with the authors of the Siboga monographs. We had made some prints of the original glass negatives and they proved to be still in good condition. Some years ago a beautifully carved wooden box was discovered in our Museum with the original brown prints of the photographs, often with notes in pencil on the reverse. All this archival material, including Weber's remaining scientific correspondence, and his extensive private correspondence with his best friend Coenraad Kerbert (1849-1927), Director of the Amsterdam zoological garden Artis, is now present in the Artis Library, University of Amsterdam. A page of Weber's diary is reproduced in Fig. 7 (note that Weber wrote this diary in Dutch).
Fig. 8 shows Captain Gustaaf Frederik Tydeman (1858-1939). He was the author
of the second and third monograph in the series Siboga Expeditie,
dealing with the ship and its scientific equipment and the hydrographical
results, respectively (Tydeman, 1902b; 1903). Later he rose to become a
Vice-Admiral and nowadays the oceanographical research vessel of the Dutch
Government is named after him (Van Oosten, 1979). Weber had a healthy respect
for him, as is proved by the following remark in his diary, dated 1 April 1899:
"Difficulty to find anchoring-ground on reef or in vicinity in reliable depth
(not less than 7 fathoms) is here very considerable too. Suddenly we touch the
reef, so that we dislodge pieces of coral. Tydeman stays as calm as ever".
From the narrative by Anna Weber we learn that he had ceded his captain's cabin
to the Weber couple and slept in the open air, on the dinner table on deck.
When it was raining a sailcloth was spread above him. Several new species and
genera were named after him, e.g. the alga Tydemania expeditionis
described by Anna Weber (in Weber-van Bosse & Reinbold, 1913: 116) and the
fish Tydemania navigatoris described by Weber (1913: 570-571).
The Siboga Expedition, charged with the research of the fauna and flora
of the varied seas in the Indo-Australian Archipelago, started from Surabaya on
7 March 1899. The total crew (Fig. 9)
consisted of 63 people, viz. 10 Dutch
Navy Officers, 6 members of the scientific staff, among them Mrs. Anna Weber,
45 (mostly Javanese) sailors, and 2 private servants (cf. Tydeman, 1903: 88).
(The participation of a lady in a marine expedition in 1899 constitutes a
landmark as well !)
Every time before dredging one had first to make a sounding (to establish the
depth). Moreover, together with each sounding the temperature of the deep
water was determined, and a water sample and a bottom sample were taken. The
thermometer and water sample bottle had to be tied to the sounding cable far
above the lead. This had to be done outboard. In Fig. 10 we see Weber seated
on a small plank outboard, peering after his instruments. That plank was
popularly called the "rack".
Weber was especially interested in the soundings in Lombok Strait. According to Alfred Russel Wallace, this strait between Bali and Lombok would mark the limit between the Asian and the Australian faunas. At present this zoogeographic boundary, running between Bali and Lombok in the south, and then through Makassar Strait between Borneo and Celebes northward, is known as Wallace's line. According to Wallace, the difference between the faunas of Bali and Lombok would be greater than that between England and Japan (Weber, 1902: 16). According to Weber, a sharp limit between the Asiatic and Australian region does not exist, but the eastern part of the archipelago gradually gets poorer in Asiatic animals, while the Australian fauna comes more and more into prominence there. Rightly, Weber moved Wallace's line far more to the Australian side, but, more importantly, he abandoned the idea of a borderline. In this context it is hard on him that his "border", which he conceived as a 50/50 proportion of Australian and Asiatic fauna elements, was called Weber's line by Paul Pelseneer in 1904 and is still known as such (Fig. 11).
Wallace's line was, among other things, based on the idea that the Lombok Strait was very deep. Therefore Weber was curious to measure the depth of this strait. The Siboga sounded a maximum depth of only 312 m there, so that Weber thought he had proved in this respect that Wallace was wrong. Nowadays it is generally accepted that the region between Wallace's line and Weber's line is a transition zone, called Wallacea. In the modern view Wallace's line between Borneo and Celebes reflects the edge of the Asiatic continental shelf, while Weber's line between Celebes and the
Moluccas is the line of faunal balance (Mayr, 1944). When we look at the track of the Siboga Expedition (Fig. 12), it can be roughly summarized as a circumnavigation along Wallace's line to the north and along Weber's line to the south. Of course this was not accidental.
Although the Siboga was charged in the first place with research of
the deep basins of the archipelago, reefs, shallower waters, and beaches were
investigated as well (Fig. 13).
In his narrative Weber (1902) acknowledges
John Murray's advice (who had participated in the Challenger Expedition) also
to examine lesser depths (up to1000 m), as they mostly have a richer fauna than
the deep-sea. After his return from the expedition, Weber received a letter
from Alexander Agassiz, in which he wrote that he had always found very few
animals on certain substrates at great depths in the Pacific. His letter ended
with the following words: "I am not happy to have been the man to find that
out" (Weber-Van Bosse, 1904: 19).
Both Max and Anna narrate about mishaps with the dredges and trawls. In
Fig. 14
the dredge is recovered. In Fig. 15
one of the bars of the trawl appears to
be broken, "imploded" as Sir Wyville Thomson (leader of the Challenger
Expedition) would have called it, by the pressure of the water column (Weber,
1902: 98). This trawl had fished at 4391 m depth. Nevertheless, the total
catch was considerable. Sometimes even huge animals were fished with baited
hook and line, e.g. sharks and the sailfish Istiophorus orientalis
(Schlegel, 1842) which was 2.68 m long (Fig. 16).
Excursions on land took place regularly as well
(Fig. 17: Weber in khaki and
the three officers forming the nautical staff in their white uniforms [G. F.
Tydeman, H. J. Boldingh, and C. E. Hoorens van Heyningen] on Banda). Of course
Weber was eager to obtain freshwater fishes and he collected a great many of
them. He was a very charming man and often the native people
(Fig. 18) offered
him rare species or he bought them in the local market place.
They also exchanged tobacco and cotton for fishes, molluscs, and ethnographic material. Their ethnographical collections went to the Ethnographical Museum of the Royal Zoological Society Natura Artis Magistra and are still extant in the Royal Tropical Institute in Amsterdam. Geological observations were also made, and as far as botany was concerned, Anna was always very busy with her Algae.