His reputation was at its height when public attention was excited by the preparations for the Embassy to China, under the conduct of Lord Macartney. An appointment as one of the gentlemen of the suite was proffered, and at once accepted by the philosopher. The East seemed not only the field in which to extricate himself from difficulties, but to open up alluring prospects of honor as well as profit. In accomplishing the objects of the Embassy, it was meant to surprise the Chinese with the power, learning, and ingenuity of the British people, for which purpose a splendid assortment of astronomical and philosophical apparatus were among the presents to his Celestial Majesty. Included in these were a planetarium and lenses of gigantic dimensions, on the former of which the labour of thirty years had been bestowed. It was invented by, and made under the direction of, the then late P. M. Hahn, and was allowed to be the most wonderful piece of mechanism ever emanating from human hands. To do justice to this department occasioned the engagement of Mr. Dinwiddie, who was first designated Machinest to the Embassy, but the title not according with his feelings, that of Astronomer was substituted, as conveying to the mind of a Chinese a more adequate idea of his station.