Bessemer’s Versatility.
So far from finding it gainful to concentrate his mind on a single problem, ignoring every other, Bessemer delighted in pursuing a wide variety of experiments, especially before his engrossing responsibilities in the manufacture of steel. In glass-making he introduced some notable improvements. He tells us: “In going over a glass-works I had noticed what I, at the moment, thought was a great oversight in the mode of proceeding. The materials employed, namely, sand, lime and soda in ascertained quantities, were laid in heaps upon the paved floor of the glasshouse, and a laborer proceeded to shovel them into one large heap, turning over the powdered materials, and mixing them together; a certain quantity of oxide of manganese was added during the general mixing operation, for the purpose of neutralizing the green color given to glass by the small amount of oxide of iron contained in the sand. The materials were then thrown into the large glass pots, which were already red-hot inside the furnace. What appeared to me to be wanting in this rough-and-ready operation was a far more intimate blending of these dry materials. A grain of sand lying by itself is infusible at the highest temperature attainable in a glass pot, and the same may be said of a small lump of lime; but both are soluble in alkali, if it be within their reach. These dry powders do not make excursions in a glass pot and look about for each other, and if they lie separated the time required for the whole to pass into a state of solution will greatly depend on their mutual contact. In such matters I always reason by analogy, and look for confirmation of my views to other manufactures or processes with which I may happen to have become more or less acquainted. I may here remark that I have always adopted a different reading of the old proverb, ‘A little knowledge is a dangerous thing’; this may indeed be true, if your knowledge is equally small on all subjects; but I have found a little knowledge on a great many different things of infinite service to me. From my early youth I had a strong desire to know something of any and all the varied manufactures to which I have been able to gain access, and I have always felt a sort of annoyance whenever any subject connected with manufacture was mooted of which I knew absolutely nothing. The result of this feeling, acting for a great many years on a powerful memory, has been that I have really come to know this dangerous little of a great many industrial processes. I have been led to say this so as to illustrate my observations on the extreme slowness of the fusion of glass by an analogy in the manufacture of gunpowder. I have shown it impossible for the dry powdered materials employed in the manufacture of glass to react chemically upon each other when they are lying far apart. Now if I take the three substances, charcoal, nitre and sulphur, of which gunpowder is composed, and break them into small fragments, then shake them loosely together, and put a pound or two of this mixture on a stone floor and apply a match, the nitre will fizzle briskly, the sulphur will burn fitfully or go out, and the charcoal will last several minutes before it is consumed. If, instead of this crude and imperfect mixture, we take the trouble to grind these ingredients under edge-stones into a fine paste with water, and then dry and granulate it, we have still the precise chemical elements to deal with which we ignited on the stone floor; but they now exist in such close and intimate contact as instantly to act upon each other, and a ton or two of these otherwise slow-burning materials will be converted into gas in the fraction of a second. The inference was simple enough, namely, to grind together the materials required to form glass, and when the heat of the furnace arrives at the point where decomposition takes place, the whole will pass into the fluid state much more quickly, and will yield a much more homogeneous glass than is obtained in the usual manner.”