Silicon
2 of the 7 encyclopedias on this shelf carry an entry for Silicon. Both are reproduced below, so you can see where they agree and where they differ.
The Encyclopedia of Founding (1892)
This substance is the base of silex or silica, and is now supposed to be a non-metallic element. More or less of this element is present in all varieties of pig iron, but whether in chemical combination or otherwise it has not yet been satisfactorily determined. Silicon acts to change the combined carbon in cast-iron to graphitic carbon. Describing the result of his experiments for ascertaining the influence of silicon upon cast-iron, W. J. Keep says: "We have seen, however, that a white iron which will invariably give porous and brittle castings can be made solid and strong by the addition of silicon; that a further addition of silicon will turn the iron gray, and that as the grayness increases the iron will grow weaker; that excessive silicon will again lighten the grain and cause a hard and brittle as well as a very weak iron; that the only softening and shrinkage-lessening influence of silicon is exerted during the time when graphite is being produced, and that silicon of itself is not a softener, or a lessener of shrinkage, but through its influence on carbon, and only during a certain stage, it does produce these effects." To produce highly siliceous iron, or siliconeisen, in the blast-furnace the blast requires to be extremely hot, the furnace driven slowly, and the charges, while containing much silica, must be highly aluminous and not markedly calcareous. When 20 per cent of silicon is present in siliconeisen the amount of carbon in the alloy is very low. To prevent honeycombing in soft cast steel which contains very little carbon, an alloy containing 8 per cent silicon, about 15 per cent manganese, and 1.3 per cent carbon is employed extensively in some steel manufactories. The presence of silicon along with manganese acts to diminish the formation of honeycomb in steel ingots. See HONEY-COMBING; SOFTENERS; ANALYSIS.
Aiton's Encyclopedia (1910)
one of the earthy chemical elements. It is most common in nature in combination with oxygen, with which it forms common sand, or silica, as scientists call it. Next to oxygen silicon is the most common element in nature, and silica, that is to say, sand, is the most common sort of soil. Clay also contains silicon. Quartz is composed of silica. Pure silicon is known only in the laboratory. A slight admixture of silicon is said to improve brass. Added to copper wire, two pounds to the thousand, it seems to increase its conductivity. Silicon, in varying amounts up to fourteen pounds to the hundred, has been employed for a long time for iron workers to harden or soften, toughen, and strengthen wrought iron . The farmer is interested in silicon. It is the soil element that gives the corn stalk, stems of grasses, and straws of grain the flinty coating that enables such slender tubes to carry heavy loads and stand staunchly in the wind. Silicon is not, however, one of the elements absolutely essential to plant life. It is also found in animal bodies,--in the quill of feathers, as spicules in sponges, and as shields in some protozoa. The hair on one's head is partly silicon. A number of stones, favorites more or less with the jeweler, as opal, agate, amethyst, carnelian, onyx, flint, chalcedony, and rock crystal, are composed chiefly of silicon. The name silicon is derived from silex, flint, because flint is made of silicon chiefly.