The astronomer Leverrier calculated the direction and rate of travel of a star, and pointed to its place in the heavens. A star appeared; yet astronomers tell us that this was not his star, that its rate of travel was other than had been predicted by Leverrier. No other appeared exactly to fulfil the astronomer's calculations. Yet Leverrier is great, and his name is familiar.<br><br>Professor Schönbein converted cotton into a new vehicle of sudden force. The belief that gun cotton might be cheaply used for purposes of offence or of defence, gave to the name of Schonbein a currency in all parts of the civilized world, and to gun cotton the position of one of the discoveries of the age.<br><br>The French experimenter has attached his name to the Daguerreotype, and this, too, is great, although a mere luxury when tested by its applicability to the necessities of man.<br><br>Few will deny to these inventions and discoveries the epithet great, when compared with others of the day; and yet their greatness is of very different kind. What, then, shall be considered a test of greatness in discovery?<br><br>A writer upon patents has said that an invention is entitled to protection from the law, when it materially modifies the result produced, or the means by which it is produced; that a patent right is due to novelty in a machine producing an old fabric in a new way, or to the manufacture of a new and very different fabric, resulting from a slight change in the machine; in other words, to novelty in the combined result of means and end. This distinction, if not legal, is apparently just; and I should, in like manner, call an invention great, in proportion to the combined amount of mind invested in its production, and of its intrinsic ability to minister to the supposed or real comfort and well-being of the race.<br><br>What, then, is the character of the discovery of etherization? And it is not idle nor superfluous to examine definitively the claims of this invention.