There must have been a large augmentation during this time, for the present which Louis XVIII. ordered to be made deducted from the collection diamonds of the value of three quarters of a million of francs. This costly present was in the form of the Order of Saint Esprit and constructed of superb diamonds. Of the robbery of 1792, the Sancy diamond and the unique blue one of sixty-seven karats have never been recovered. Since the inventory of 1810 two beautiful gems have also disappeared. One of these was the magnificent opal which Josephine wore, and which was known as the Burning of Troy. The other was the beautiful brilliant of thirty-four karats which was obtained by M. Elias for Napoleon. This was the much-loved gem which the Emperor is said to have carried with him on his person, and which was asserted to have been lost in the rout at Waterloo. The magnificent blue diamond, which was regarded as one of the marvels of the mineral kingdom, has never been recovered. Its early history has also been lost, but the gem is believed to be the identical stone which Tavernier brought from India and sold to Louis XIV. At that time it was described as a gem of a beautiful violet hue, but of a bad form, being flat and thin. Its weight in this condition was 112³⁄₁₆ karats, which would probably afford a fine brilliant of the size of the missing stone, 67²⁄₁₆ karats. History has failed to trace the wanderings of this gem since its departure from the Louvre, but suspicion rests upon the superb blue diamond which was in the possession of the English banker, the late Mr. Hope. However, the English diamond weighs but 44¹⁄₂ karats. Therefore a loss of quite 22 karats was incurred in recutting the stone in order to escape detection. The Regent diamond, which was found uninjured in the ditch of the Champs d’Elysées, is in reality the most beautiful diamond yet known in the world. It is not the largest, but it is the most perfect of all the paragons, being almost faultless in its transparency and purity, as well as in its exact and symmetrical form.