Loam
3 of the 6 encyclopedias on this shelf carry an entry for Loam. All 3 are reproduced below, so you can see where they agree and where they differ.
The Encyclopedia of Founding (1892)
Foundry loam is a mixture of sand with clay and some form of venting medium. Refractory fire-sands suitable for loam are of themselves too friable to form a compact, hard body. Clay is therefore added to impart adhesiveness, with some accompanying substance, as manure, etc., to counteract its imporous quality, and leave the mixture when dry a hard, unyielding substance, that is permeated with countless small holes through which the surface gas finds its way to the exterior. The proportion of clay employed must be regulated by the class of castings the loam is for. The following mixtures are for ordinary use in almost any foundry, and any sands which approximate in their nature to the general run of Jersey, fire, and moulding sands will answer. If the castings are unusually light, as thin plate castings in loam, the clay-water should be proportionately thinner. Hand-made Loam for Loam-moulds and Core-barrels.--Fire-sand, 5; moulding-sand, 2; horse-manure, 1 1/2. Mix with thick clay-water. Mill-made Loam for Loam-moulds and Core-barrels.--Fire-sand, 7; moulding-sand. 2; horse-manure, 2. Mix with thick clay-water, and grind no longer than is necessary to mix the ingredients intimately together. See HORSE-MANURE; VENTING; FACING-SAND; LOAM-MILL. Loam-board is a technical term for any strickle, strike, sweep, or templet, so called, that may be employed for forming some part of a mould in loam; whether it be drawn along by the hands of a moulder horizontally, as for a pipe, attached to a centre-spindle to form circular moulds vertically, or be secured fast whilst the mould or core rotates part it, as for cores, both horizontal and vertical. Such boards should be bevelled on the edge, using the sharp edge for roughing up and the opposite way for skinning. See SWEEP-BOARD; ROUGHING-UP; STRICKLE; LOAM. Loam-bricks are made in cast-iron moulds. The moulds being set on a smooth plate in the oven are filled with stiff loam and allowed to remain until dry. They are then useful for fashioning into cores with the saw and file, or may be used for building in parts where, on account of their rigidity, the ordinary bricks would interfere with the free contraction of the casting. The loam-bricks, being less rigid, yield readily to the pressure. See LOAM.
Collier's New Encyclopedia (1921)
alluvial soil, consisting of sand and clay soil in considerable quantity. tes. , If one or the other largely predominates the soil ceases to be loam. In founding, a mixture which essentially consists of sand and clay, the former largely predominating, with a certain quantity of horse-dung added, or some equivalent for the same, such as chopped straw, sawdust, cow-hair, etc. Beds of loam are sometimes found of nearly suitable composition, but it is more commonly made up by blending different sorts of sand, clay, etc., in a mill resembling a pugmill. In molding, it is always used quite wet, like plaster, but is dried perfectly before pouring. It is employed for large work in both brass and iron, obviating the use of a pattern.
Aiton's Encyclopedia (1910)
. See Soil
What Has Changed in the Last Century
Both the 1892 founding dictionary and Collier's in 1921 define loam as a blend of just two fractions, "sand and clay" — Collier's adds that "if one or the other largely predominates the soil ceases to be loam." Modern soil science recognises three size fractions, and loam is fixed by percentage limits on the standard texture triangle: roughly 40 per cent sand, 40 per cent silt and 20 per cent clay, with silt the component the old entries do not name at all. The foundry sense has all but vanished: loam moulding with horse-manure as the venting medium, and the loam-bricks and sweep-boards of 1892, gave way through the twentieth century to green-sand, chemically bonded and resin-shell moulds, and today to investment and lost-foam casting. A 1921 reader looking up "loam" would have expected the foundry meaning as readily as the garden one; today the soil sense is effectively the only living use.
Written for this edition, 2026.