THERE is perhaps no department of general knowledge about which ordinary readers are less informed than that which relates to the diamond. Even the mineralogist, the chemist, and the natural philosopher have limited themselves to a very partial study of the origin, the history, and the properties of this remarkable substance. Ranked as it must be among the bodies of the mineral world, and regarded as it has ever been as the most valuable production which the earth embosoms, it has always occupied, from its value as well as its beauty, the first place among those precious stones which it is the highest ambition of wealth and power to accumulate. But though thus associated with zircon, sapphire, ruby, topaz, and the emerald, it essentially differs from them all in its origin, its composition, and its physical

Travels through the Gold and Diamond District of Brazil. By JOHN MAWE. London, 1812.

Notice respecting a Singular Structure in the Diamond. By DAVID BREWSTER, LL.D., F.R.S., and Sec. R.S.E. In Edinburgh Philosophical Journal, vol. iii. p. 98. Edin. 1820. This erudite and instructive treatise is attributed to Sir David Brewster, unquestionably the greatest living optical philosopher.-ED.

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properties; and while it takes precedence of them all, it is nevertheless the meanest in its elements, the weakest in its structure, and the most perishable in its nature. The fullgrown diamond indeed exceeds in value more than a hundred thousand times its mass in gold:-it is the most cherished property, and the proudest ornament of kings:*-It is the most prized, and the brightest jewel in the chaplet of beauty, and yet it is but a lump of coal, which it reduces to a cinder, and dissipates into that insalubrious gas which ascends from the most putrid marsh, and bubbles from the filthiest quagmire.

The word diamond is derived, through the French diamant, from the Greek word Adauas, invincible, and this again from a and Sauaw, to crush or subdue,-from its supposed property of resisting the action of fire and the heaviest strokes of the hammer. f

*Maximum in rebus humanis, non solum inter gemmas, pretium habet adamas, diu non nisi regibus et iis admodum paucis cognitus.-Plin. Hist. Nat., lib. xxxvii. cap. 15.

+ Incudibus hi deprehendunter, ita respuentes ictum, ut ferrum utrinque dissultet incudes etiam ipsae dissiliant. Quippe duritia inenarrabilis est

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