Prop., &c. Pure stearic acid crystallises in
milk-white needles, which are soluble in ether and in cold alcohol, and forms salts with the bases, called stearates. The commercial acid is made into candles. See Candles, Fat, Oils (Fixed), and Tallow.
STE′ARIN. C57H110O6. The solid portion of fats which is insoluble in cold alcohol.
Prep. Pure strained mutton suet is melted in a glass flask along with 7 or 8 times its weight of ether, and the solution allowed to cool; the soft, pasty, semi-crystalline mass is then transferred to a cloth and is strongly pressed as rapidly as possible, in order to avoid unnecessary evaporation; the solid portion is then redissolved in ether, and the solution allowed to crystallise, as before. The product is nearly pure.
Prop., &c. White; semi-crystalline; insoluble in water and cold alcohol; soluble in 225 parts of cold ether, and freely so in boiling ether. It melts at 130° Fahr. The stearin of commerce is stearic acid.
STEAROP′TEN. The name given by Herberger to the concrete portion or camphor of volatile oils. Bizio calls it stereusin.
STEEL. This important material may be defined as iron chemically combined with sufficient carbon to give it extreme toughness and hardness without brittleness. According to one of our greatest authorities on metallurgy, steel should contain from ·833% to 1·67% of carbon, these numbers referring respectively to the softest and the hardest varieties.
By some authorities silicon in small quantities is supposed to be a useful ingredient in steel, and to increase its capacity for being hardened; an opinion dissented from by others, who hold that its presence has a tendency to interfere with the welding of the metal. Faraday and Stodart believed that the addition of small quantities of chromium and iridium to steel served to improve its quality, and the same has been asserted of tungsten and titanium; but on these points there is still a divergence of opinion, and no satisfactory decision has yet been arrived at concerning them.
Manganese has also been credited with the property of improving steel, but as it has been found that only a very minute quantity of the manganese is taken up by the steel, an indirect influence may possibly be exercised by it, viz. its power of uniting with the stage, and of carrying away any prejudicial excess of sulphur and phosphorus with it; and in this manner it may contribute to the increased purity of the metal. The addition of manganese to cast steel constitutes Mr Heath’s patent, the chief advantage of which is that blistered steel made from British bar iron can be substituted for the much more expensive Swedish and Russian iron, in certain branches of iron manufacture.
“Among the various substances which are frequently present in malleable iron and in cast iron, those which are more prejudicial to