90 HISTORY OF THE [1840-50 shadow of doubt that the displacements observed were actually the proportionate projections of the earth's orbit and nothing else. All these points were surveyed critically in the most careful way by Main (Memoirs, 12). It was a just estimate of the actual position that awarded the Medal to Bessel in 1841. Henderson has sometimes been blamed for undue caution and delay. This seems a wrong view of the case ; with the means at his disposal, caution and confirmation were an obligation. After his results were confirmed, the Council felt that he too should have recogni- tion. But they missed the right opportunity for action. In 1843 the material was before them, and no name was proposed for the Medal. In 1844 November, Henderson's name was put forward, but in the same month he died. In the same month too, a painful, long and, as it proved, a fatal illness removed Bessel from the scene. The figure of Bessel, loved and admired, has filled a prominent place in the development of astronomy ; it will continue to do so ; astronomy won him, with its peculiar appeal, in the first flush of his genius and strength, from his clerkship in a merchant's office. He established its foundation as much as it could be given to one man to do. It is surprising that a man with so great an impulse for thoroughness could bring so many works to definite conclusions. For example, he began his studies with the Kcenigsberg heliometer by devoting a paper to the trigonometrical calculation of the field of its object glass. He was known in this country chiefly by his writings, but he visited it in 1842, when he passed a week, along with Jacobi, in Henderson's company at Edinburgh and in the Highlands, and stayed with Herschel, who learnt from him his intention of investigating the errors of Uranus on the hypothesis of an exterior planet. Fame has given Bessel no more than he earned, but it has done less than justice to Henderson. There can be no thought of com- paring the two men together ; Henderson was avowedly a culti- vator of the methods of others. " At the outset of his career he was led (probably by the commendation of them in our Memoirs) to study attentively the methods of the German astro- nomers, particularly those of Bessel and Struve, upon whose model he formed his practice, and from which he never departed." I would remark that as astronomy expands, the originator of methods, especially where they involve increase of labour, renders himself more and more ineffectual by his own advances, unless he finds unselfish, able, appreciative imitators to apply his methods far and wide. It needs those qualities, and imagination as well, to see that it is worth doing. Henderson never had a good instrument to work with. It was entirely due to his care
