The first ingredient in making glass, to which we were introduced, was contained in a goodly row of barrels in full tap, marked with the esteemed brand of "Truman, Hanbury, Buxton, and Co." It is the well-known fermented extract of malt and hops, which is, it seems, nearly as necessary to the production of good plate glass, as flint and soda. To liquefy the latter materials by means of fire is, in truth, dry work; and our _cicerone_ explained, that seven pints per day, per man, of Messrs. Truman, Hanbury, Buxton, and Company's Entire, has been found, after years of thirsty experience, to be absolutely necessary to moisten human clay, hourly baked at the mouths of blazing furnaces. These furnaces emit a heat more intense than the most perspiring imagination can conceive, or the stanchest thermometer indicate. An attempt to ascertain the degree of heat was once made: a pyrometer (a thermometer of the superlative degree, or "fire-measurer"), was applied to the throat of a furnace--for every furnace has its mouth, its throat, and its flaming tongues; but the wretched instrument, after five minutes' scorching, made an expiring effort to mark _thirteen hundred degrees above boiling point_, cracked, was shivered into bits, and was finally swallowed up by the insatiable element whose proceedings it had presumptuously attempted to register. Having, by this time, crossed a yard, we stood on the edge of a foul creek of the Thames, so horribly slimy, that a crocodile or an alligator, or any scaly monster of the Saurian period, seemed much more likely to be encountered in such a neighborhood than the beautiful substance that makes our modern rooms so glittering and bright; our streets so dazzling, and our windows at once so radiant and so strong. "In order to understand our process thoroughly," said the obliging director of the seven acres of factory and the four hundred operatives we had come to see, "we must begin with the beginning. This," picking up from a heap a handful of the finest of fine sand--the glittering pounce, in fact, with which our forefathers spangled their writing--"is the basis of all glass. It is the whitest, most highly pulverized flint sand that can be procured. This comes from Lynn, on the coast of Norfolk. Its mixture with the other materials is a secret, even to us. We give the man who possesses it a handsome salary for exercising his mystery."