On the score of geographical distribution, gold must be deemed a common metal, as common as copper, lead, or silver, and far more common than nickel, cobalt, platinum, and many others. Theorists have propounded curious rules for the occurrence of gold on certain lines and belts, which have no existence but in their own fancy. Scarcely a country but has rewarded a systematic search for gold, though some are more richly endowed than others, and discoveries are not always made with the same facility. The old prejudices, which made men associate gold only with certain localities hindered the development of a most promising industry even within the British shores. Despite the abundant traces of ancient Roman and other workings, the gold-mines of Wales were long regarded as mythical; but recent extended exploitation has proved them to be rich. This is notably the case in the Dolgelly district, where considerable gold occurs, both in alluvial gravels and in well-formed quartz veins traversing the Lower Silurian Lingula beds and the intruded diabasic rocks called 'greenstone' in the Geological Survey. A peculiarity of the veins is the common association of magnesian minerals. The gold is about 20 or 21 carats fine, and often shows traces of iron sesquioxide. So long ago as 1861 some £10,000 worth of gold per annum was taken out of the Clogan mine by imperfect methods. Some samples have afforded 40 to 60 ounces per ton--a most remarkable yield. There are probably many veins still waiting discovery. A calculation was made in 1881 that the total gold extracted from all sources up to that date from the creation had been over 10,000 tons, with a value of about 1500 millions sterling. California, to the end of 1888, was reckoned to have afforded over 200 million pounds' worth, and this figure is exceeded by the Australian colony of Victoria. The origin of gold-bearing mineral veins is inseparably connected with that vexed question, the origin of mineral veins generally. By far the most common matrix of vein-gold is quartz or silica, but it is not the only one. To pass by the metals and metallic ores with which gold is found, there are several other minerals which serve as an envelope for the precious metal. Chief among them is lime. Some of the best mines of New South Wales are in calcareous veins. Sundry gold-reefs in Queensland, New South Wales, Victoria, and Bohemia are full of calcite. Dolomite occurs in Californian and Manitoban mines; and apatite, aragonite, gypsum, selenite, and crystalline limestone have all proved auriferous, while in some cases neighbouring quartz has been barren. Felspar in Colorado and felsite magnesian slate in Newfoundland carry gold. NUGGETS. [Illustration: Welcome Nugget.]