30. The porcelain wares of Europe are superior to those of the Chinese, in the variety and elegance of their forms, as well as in the beauty of the designs executed upon them; but, as some of the processes successfully practised in China, remain still to be learned by the Europeans, the Oriental porcelain has not yet been equalled in the hardness, strength, and durability of its body, and in the permanency of its glaze. The manufacturers of Saxony are said to have been the most successful in their imitations in these respects. 31. The porcelain earths are found in various parts of the United States, but particularly at Wilmington, in the state of Delaware. Nevertheless, there is now but one porcelain manufactory in our country, and this is yet in its infancy. The establishment is located in Philadelphia, and it has been lately incorporated, with the privilege of one hundred thousand dollars capital. 32. The principle of induration by heat, is the same in the manufacture of earthen wares as in making bricks; and, as the latter can be more easily dispensed with than the former in a primitive state of society, it is but reasonable to suppose that earthen ware was first invented; but the art of making bricks must have been practised before the deluge, or the posterity of Noah would not have attempted so soon as about one hundred years after that catastrophe, to build a city and a tower of these materials. It is, therefore, evident, that this art was of antediluvian origin; and it was probably one of the earliest brought to any degree of perfection. 33. The art of the potter was practised more or less by every nation of antiquity, and the degree of perfection to which it was carried in every country corresponded with the state of the arts generally. The Greeks were consequently very celebrated for their earthen wares. The Etruscans have also been particularly noted for their manufacture of the elegant vases which have been dug, in modern times, from the depositories of the dead, in Lower Italy. 34. Until the commencement of the manufacture of porcelain in Europe, this art continued in a very rude condition, although practised to a considerable extent in many places. It was much improved in England about the year 1720, by the addition of flints to the usual material; and, between thirty and forty years after this, it was brought to great perfection, in all its branches, chiefly through the scientific exertions of the celebrated potter, Josiah Wedgewood. [Illustration: GLASS BLOWER.] THE GLASS-BLOWER. 1. Glass is a substance produced from a combination of silicious earths with alkalies, and, in many cases, with metallic oxydes. The basis of every species of glass is silex, which is found in a state nearly pure in the sands of many situations. It is also found in the common flints and quartz pebbles.