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Oils and Fats
Fats are merely solid or semi-fluid oils. The fixed oils and fats form a well-defined group of organic compounds, which are abundantly…
Old Red-sandstone
This group of sandstone lies below the carboniferous strata, and was called "old" to distinguish it from a series of similar strata which…
Oleine
See OILS. Olive Bronze Dip for Brass.--Nitric acid 3 ounces, muriatic acid 2 ounces; add titanium or palladium. When the metal is dissolved…
Onyx
A chalcedony, with alternate layers of white, black, and brown. It is found in Saxony, Arabia, and Ireland, and is used largely for cameos…
Oolite
A variety of limestone, so called from its being composed of small rounded grains resembling the roe of a fish, cemented together by a…
Opal
A species of the quartz family of minerals, from which it differs in containing 5 to 13 per cent of water. It is a precious stone…
Open-hearth Cast Steel
This steel is produced on a large scale and is so called to distinguish it from steel made by the Bessemer process, by puddling, or from…
Open-sand Moulding
The process of moulding castings that have one plain side, in the sand floor of the foundry. Even for such castings it is usual to cover…
Oreide
An alloy supposed to be of French origin; it is used as a substitute for "ormolu" in the manufacture of cheap jewelry, excelling the latter…
Ormolu
A variety of brass having a near resemblance to gold, containing from 25 to 50 of zinc to 50 of copper, according to the tint desired. To…
Osmium
This metal was discovered by Tennant in 1803. It belongs to the class usually termed "noble," and occurs in association with platinum in…
Ounce
A division of the pound weight in English. In Troy weight it means the twelfth part of a pound, and weighs 480 grains. In avoirdupois…
Oxalic Acid
This substance exists as binoxalate of potash in common sorrel and the rhubarb plant, which accounts for the acid taste common to those…
Oxidation
The process or converting metals or other substances into oxides, by combining with them a certain portion of oxygen. It differs from…
Oxide, Carbonic
When a mixture of purified charcoal and oxide of iron or zinc is exposed to a strong heat in an iron retort, the metallic oxide is…
Oxides
Substances combined with oxygen without being in a state of acid. The metallic oxides are the most important, and occur naturally as…
Oxygen
This gas was obtained by Dr. Priestley in 1774 from red oxide of mercury exposed to a burning lens, and again in the following year by the…
Oxyhydrogen Blowpipe
An apparatus for burning oxygen and hydrogen together to produce very high temperature. Now extensively used for melting platinum and other…
Oyster-shells
The carbonate of lime being the prevalent component of the oyster-shell, it has on that account been substituted for limestone as a flux in…
Oil-stone – Overhead Cranes
See WHETSTONE. See BLACK SAND; NEW SAND; FACING-SAND.