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In philately, chalky paper is a type of paper coated with a chalky solution for security purposes. [1] The postmark cannot be removed without damaging the surface of the stamp [2] thus discouraging erasure of cancellations and fraudulent reuse of stamps. The paper was first coated with a chalk-like powder, and the ink for the stamp was then ...
The paper was coated with a solution containing a suspension of chalk. The British government used chalky paper in many of its colonies. One destructive test of chalk paper is to rub a piece of silver on the paper. A black, pencil-like mark will result if the paper is chalky. British Honduras SC# 62-71 (chalky) Mozambique Company SC#4 (chalked ...
This is a list of U.S. state soils. A state soil is a soil that has special significance to a particular state. Each state in the United States has selected a state soil, twenty of which have been legislatively established. These official state soils share the same level of distinction as official state flowers and birds.
Calcareous soils are relatively alkaline, in other words they have a high pH. They are characterized by the presence of calcium carbonate in the parent material; the carbonate-ion is a base. Additionally, these soils may have a calcic horizon, a layer of secondary accumulation of carbonates (usually calciumcarbonate or magnesiumcarbonate) in ...
In agriculture, chalk is used for raising pH in soils with high acidity. [25] Small doses of chalk can also be used as an antacid. [26] Additionally, the small particles of chalk make it a substance ideal for cleaning and polishing. For example, toothpaste commonly contains small amounts of chalk, which serves as a mild abrasive. [27]
A crossword (or crossword puzzle) is a word game consisting of a grid of black and white squares, into which solvers enter words or phrases ("entries") crossing each other horizontally ("across") and vertically ("down") according to a set of clues. Each white square is typically filled with one letter, while the black squares are used to ...
Soil texture is determined by the relative proportion of the three kinds of soil mineral particles, called soil separates: sand, silt, and clay. At the next larger scale, soil structures called peds or more commonly soil aggregates are created from the soil separates when iron oxides , carbonates , clay, silica and humus , coat particles and ...
The deckle leaves the edges of the paper slightly irregular and wavy, called "deckle edges", one of the indications that the paper was made by hand. Deckle-edged paper is occasionally mechanically imitated today to create the impression of old-fashioned luxury. The impressions in paper caused by the wires in the screen that run sideways are ...