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192 will be thousands—perhaps thirty thousand more—yet discovered." The discovery of the fourth, called Vesta, he pronounced "an event of such consequence" as to "engage his immediate attention." He called it "a valuable addition to our increasing catalogue of asteroids"; and he spoke of the "celebrated discoverers" as inducing "us to hope that some farther light may soon be thrown upon this new and most interesting branch of astronomy." Dr. Olbers himself wrote to Herschel that Vesta "was not to be distinguished from a fixed star"; while Schroeter, the countryman and neighbour of Olbers, had already communicated a paper to the Royal Society in which he said: "Its image was, without the least difference, that of a fixed star of the 6th magnitude with an intense radiating light; so that this new planet may with the greatest propriety be called an asteroid" That one scientific man should attack, or rather slander, another for giving to these small bodies a scientifically appropriate name, on the ground that he thereby intended to derogate from the credit of his own friends, whom he publicly extolled as "celebrated discoverers," seems incredible. Yet it was done.

By a most ingenious contrivance he managed to obtain approximate values for the diameters of Ceres and Pallas. The former he found to be 161⋅6 miles; the latter smaller, 147 or 110$1⁄3$ miles. So small is Pallas that it would require many thousands equally small to make up a planet no larger than Mercury. The colour of Ceres he found to be "ruddy, but not very deep"; that of Pallas, "milky whitish."