In the years 1804-5 Wollaston first made known to the world the existence of the two metals, palladium and rhodium, which he found were contained in the ore of platinum, associated with osmium and iridium, two metals discovered about the same time by Mr. Tennant. In 1809 he showed that the supposed new metal, tantalum, was identical with columhium, previously discovered by Mr. Hatchett; and shortly before his death, he transmitted to the Royal Society a communication, constituting the Bakerian lecture of 1828, in which he fully describes his ingenius method of rendering platinum malleable. From this invention he is stated to have acquired more than 30,000_l._ Dr. Wollaston's knowledge was more varied, and his tastes less exclusive, than any other philosopher of his time, except Cavendish; but optics and chemistry are the two sciences in which he made the greatest discoveries. To him we owe the first demonstration of the identity of galvanism and common electricity, and the first explanation of the cause of the different phenomena exhibited by them. Dr. Wollaston was accustomed to carry on his experiments in the greatest seclusion, and with very few instruments; he was also endowed with an extreme neatness of hand, and invented the most ingenious methods of determining the properties and constituents of very minute quantities of matter. It is related by Dr. Paris (in his Life of Davy), that a foreign philosopher once calling on Wollaston with letters of introduction, expressed a great desire to see his laboratory. "Certainly," replied Wollaston, and immediately produced a small tray, containing some glass tubes, a blowpipe, two or three watch-glasses, a slip of platinum, and a few test-tubes. Another anecdote is told of him, that, having been engaged one day in inspecting a monster galvanic battery constructed by Mr. Children, he accidentally met, on his way home, a brother chemist, who knew of Mr. Children's grand machine, and uttered something about the inconvenience of it being of such an enormous size; on this Wollaston seized his friend by the button, led him into a bye corner, where, taking from his waistcoat pocket a tailor's thimble which contained a galvanic arrangement, and pouring into it the contents of a small phial, he astonished his friend by immediately heating a platinum wire to a white heat. He also produced platinum wire so extremely fine as to be nearly imperceptible to the naked eye.