His lectures upon œconomy had the recommendation of novelty, and produced so much applause, that in 1770 he was made ordinary professor of that science. They were attended by the flower of the studious youth of all countries, Göttingen being at that period one of the most popular universities in Europe; and many even of the distinguished statesmen and public functionaries of Germany did not disdain to be ranked among his auditors. He was in the habit of accompanying them himself into the workshops, to give them a practical knowledge of the different processes and handicrafts of which he had explained the theory. Once a week, also, he held a Practicum Camerale, a scientific meeting, at which he explained subjects of œconomy, administration, and finance, illustrating them by readings from a great variety of sources. He composed, to serve as a guide in this course of instruction, treatises on rural œconomy, policy, finance, commerce, and other departments of knowledge; which, though since carried to a higher degree of perfection, owed to Beckmann their first systematic form. He never entirely relinquished these public lectures, but insensibly his private studies took a direction altogether historical, the motives for which it may not be uninteresting to point out.
It is indispensably requisite at Göttingen that every professor should be able to give account of the progress and existing state of the science to which he is appointed. Any one, who two years after the publication of a work of importance in his department should not have read and analysed it, with a view of enriching his own observations, would not be regarded as a worthy successor to the chair of Haller, of Mosheim, of Gessner and Michaelis. Beckmann, who had studied at Göttingen at a time when the example of these great men dictated the law and gave the tone to the University, and perhaps to the literature of Europe, was determined to keep pace with the spirit of the age, and not to remain ignorant of the great advances then making throughout Europe, in the numerous sciences which furnished the subjects of his practical investigations. But this was a task of no slight magnitude: and indeed when the immense additions to so many different sciences are considered, can it be wondered at, that, notwithstanding his utmost zeal and application, he found it impossible to read up all the important works which had appeared since 1770, in chemistry, physics, natural history and mathematics? Despairing of success in so Herculean an undertaking, he began to entertain feelings of aversion towards what he deemed the innovations, which were then changing the face and enlarging the scope of science. But his course of lectures, turning principally on practical matters, was not materially affected; he was, however, so fearful of falling under the imputation of being behind the progress of the age, that he devoted his mind, peculiarly fitted for this kind of study, almost exclusively to the history of arts and trades; employing in the illustration of his subjects, the materials to which he had access in the very extensive library belonging to the university; and it is to his consequent labours and researches that we owe the “History of Inventions and Discoveries.” In this work, Beckmann traces their first germs from the remotest periods of antiquity, and following their gradual development, exhibits the latest improvements among civilized nations with almost unequalled acumen and ability. It abounds with invaluable materials respecting the general history of the origin and progress of the mechanic arts, which are so important a branch in civilization; and what must give it an additional value in the eyes of all who are unwilling to place reliance on assertions unsupported by authority, or may be anxious to investigate the subject more deeply, the most scrupulous references to original authorities accompany each article. Among the numerous other works of merit for which we are indebted to the literary industry of Beckmann, are, “A History and Analysis of early Voyages and Travels,” a highly interesting collection, which occupied the last years of his life, and was left unfinished at the eighth number; elaborate editions of “De Mirabilibus Auscultationibus,” attributed to Aristotle, 1786; “Antigoni Carystii Historiæ Mirabiles,” 1791; and “Marbodi Liber de Gemmis,” 1799; publications which required the rare combination of physical knowledge with philological learning.
The Royal Society of Göttingen had, in the year 1772, admitted him one of its members, and from that period to 1783 he continued to supply their proceedings with interesting memoirs (all written in Latin), among which are the following: “On the Reduction of Fossils to their original substances;” “On the History of Alum;” “On the Sap of Madder;” “On Meerschaum, from which are formed the heads for tobacco pipes;” “On the History of Sugar,” &c. After this period, however, he declined participating any longer in the labours of this learned body; owing, probably, to a change in the objects of his own particular studies. In 1784 he was created an aulic councillor of Hanover; in addition to which he was elected member of the Imperial Academy of Naturalists, of the Swedish Society of Science, of the Academies of Norway and Mayence, of the Physiographical Society of Lund, and of almost all the learned societies in Germany and the North of Europe.
With a copious knowledge of the principal sciences, Beckmann united extensive reading in the works of ancient and modern writers, not only in reference to their immediate connection with his main studies, but in respect also to their application generally to every other branch. Convinced that every professor ought, as much as possible, to have thoroughly searched into all matters relating to the subject on which he treats, he spared no expense in forming a most extensive, as well as choice library; at the same time he did not fail to avail himself of the rich intellectual stores contained in that belonging to the university. His mind being wholly directed to all that is practical in human knowledge, it was his especial endeavour to bring it into systematic rules, based upon fundamental principles. To him particularly is to be ascribed the merit of having been the first to give to agriculture its scientific form, and to have separated it more distinctly than heretofore from the administrative and financial departments. The number of pupils indebted to him for their education, and who, eventually—whether filling offices of state or following his footsteps as professors—brought into effect the principles he had taught them, formed a very numerous body; and whilst he was thus the means of considerably enlarging the circle of academic subjects for the instruction of the student, he contributed not a little towards the prosperity of the university