As a notable gem in a famous private collection the Hope Blue enjoyed for years a quiet distinction. It was set round about with pearls and white diamonds to enhance its azure and had a beautiful pearl-drop for pendant. Altogether it was a neat and delightful trinket; price one hundred and fifty thousand dollars. Little or nothing was thought about it until the death of the Duke of Brunswick, the mad diamond-miser who used to sleep surrounded with mechanical pistols which were warranted to go off with such fatal facility that it is a marvel they did not shoot his Grace in mistake for a burglar. In 1874, the Brunswick diamonds came to the hammer and amongst them a blue stone of six carats weight. Mr. Streeter, than whom there exists no better authority on diamonds, had this stone and the Hope Blue put into his hands together. He found that they were identical in color and quality, that the sides of cleavage matched as nearly as could be determined after the cutting, while the united weights plus the calculated less from re-cutting amounted to the weight of the French Blue. He immediately drew the very natural conclusion that both these stones were once united and formed the Blue Diamond brought from India by Tavernier. He, it will be remembered, called it of a "lovely violet" and as only very few other blue diamonds are known to be in existence, and they are all of a pale blue tint, we must admit that the weight of evidence hangs strongly in favor of Mr. Streeter's reasoning. [Illustration: "HOPE BLUE" DIAMOND, AS MOUNTED.] The collection of the late Mr. Hope was a very large and valuable one. Of course the blue diamond was its chief glory, but it contained other gems of value. A portion of these were recently offered for sale consisting of diamonds, sapphires, opals and pearls, set and unset, and of rings, crosses and bracelets, of all sorts of shapes and patterns. The display reminded one of a jeweller's show-case except for this remarkable difference. There were no two objects alike, and all showed the refined taste of an amateur rather than the massive showiness of the mere commercial jewel. Mr. Hope engaged an eminent jeweller, Mr. Hertz, at an eminent fee (five thousand dollars) to catalogue his jewels. This gentleman performed his task with business-like succinctness, using no unnecessary words to describe the numerous precious objects. But when he reached the Blue Diamond he launches out into unbridled enthusiasm. He says: