Wallace's Malay Archipelago also marked the culmination of a progression in the significance accorded to field observation, or perhaps its very definition. Crawfurd, Earl, and Wallace all managed to combine the functions of field observer and metropolitan author and ethnologist. But where Crawfurd's contemporaries could regard his declarations on both Malays and Papuans as authoritative, Wallace's field methods, which owed as much to his formation as a surveyor as they did to established procedures amongst naturalist collectors (Moore 1997), radically raised the standard of evidence for racial discrimination.

The moral imprimatur of presence, or at least proximity, might have contributed to Crawfurd's standing; but his claim to field observation of Papuans was more the virtual presence of the well read philologist: 'I have never visited the island of New Guinea, but I have paid much attention to the subject, and ought to know something about it'.^[57] For Crawfurd's critics, however, the limited scope of his observations failed to warrant his propensity to theorize. Raffles (1822:122) was not alone in his assessment that Crawfurd possessed 'a rage for generalizing on partial and insufficient data, and the substitution of bold speculation for the patient investigation of facts. With materials sufficient, perhaps, for an account of one of these islands, the author has attempted to grasp the whole'.^[58]

Earl's distrust of metropolitan savants (amongst whom he would probably have numbered Crawfurd) contributed to his championing of presence in the field as the sole source of authority. The vocabulary of observation in Earl's work is considerably more precise in its identification of locations and of the position of the observer — whether that of a Dutch traveller in translation or Earl's explicit positioning of himself within the frame.^[59] Earl's coyness about the exact details of his own encounters with Papuans and with the island of New Guinea is itself indicative of the significance that he attributed to personal observation in the field.

Certainly, by Wallace's time, the entire grammar of observational authority had been transformed and the distinctions between explorers, travellers, and scientific travellers more sharply drawn. Wallace proposed a commitment to field observation that went further than Earl, insisting that observers actually live amongst indigenous communities:

The privileging of field observation through this 'residency rule' was essential if the all-important details of moral character were to be correctly described and made available to ethnologists: 'Ethnologists', complained Wallace, 'have too often to trust to the information of travellers who passing rapidly from country to country have too few opportunities of becoming acquainted with peculiarities of national character, & scarcely even with those of physical conformation'.^[60]

However, the sheer fact of presence in the field was no longer sufficient in itself. Wallace (1880b:153) would later damn d'Albertis with faint praise in a review of the Italian's account of his New Guinea expeditions. D'Albertis had 'all the best qualities of an explorer — enthusiasm, boldness, and resource, a deep love of nature, great humanity, and an amount of sympathy with savages', wrote Wallace before delivering a stinging verdict: 'To the character of a scientific traveller he makes no claim, and those who expect to find any sound generalizations from the results of his observations will in all probability be disappointed'. The capacity to deliver 'sound generalizations' from their own field observations was a trait common to Crawfurd, Earl, and Wallace, but securing recognition for their accounts required that their senses be as keen to the prevailing winds of scientific opinion in London and Europe as they had been to human difference in the Malay Archipelago.