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POTASSIUM [ See also: element, belonging to the See also: group termed the metals of the alkalis
.
Although never found See also: free in nature, in combination the See also: metal is abundantly and widely distributed
.
In the oceans alone there are estimated to be 1141,X 1012 tons of sulphate, K2SO4, but this inexhaustible store is not much See also: drawn upon; and the " See also: salt gardens " on the See also: coast of See also: France lost their See also: industrial importance as potash-producers since the deposits at See also: Stassfurt in See also: Germany have come to be worked
.
These deposits, in addition to See also: common salt, include the following minerals: sylvine, KCI; carnallite, KCl•MgC12.6H2O (transparent, deliquescent crystals, often red with diffused See also: oxide of iron); kainite, K2SO4•MgSO4•MgC126H2O (hard crystalline masses, permanent in the air); kieserite MgSO4•H20 (only very slowly dissolved by See also: water); besides polyhalite, MgSO4•K2SO4.2CaSO4.2H2O- See also: anhydrite, CaSO4; salt, NaCl, and some minor components
.
These potassium minerals are not See also: con-fined to Stassfurt; larger quantities of sylvine and kainite are met with in the salt mines of Kalusz in the eastern Carpathian Mountains
.
The Stassfurt minerals owe their industrial importance to their solubility in water and consequent ready amenability to chemical operations
.
In point of absolute mass they are insignificant compared with the abundance and variety of potassiferous silicates, which occur everywhere in the See also: earth's crust; See also: orthoclase (potash See also: felspar) and potash See also: mica may be quoted as prominent examples
.
Such potassiferous silicates are found in almost all rocks, both as normal and as See also: accessory components; and their disintegration furnishes the soluble potassium salts which are found in all fertile soils
.
These salts are sucked up by the roots of See also: plants, and by taking See also: part in the See also: process of See also: nutrition are partly converted into oxalate, tartrate, and other organic salts, which, when the plants are burned, are converted into the carbonate, K2CO3
.
It is a remarkable fact that, although in a given See also: soil the soda-content may predominate largely over the potash salts, the plants growing in the soil take up the latter: in the ashes of most See also: land plants the potash (calculated as See also: K20) forms upwards of 90% of the See also: total See also: alkali
.
The proposition holds, in its general sense, for See also: sea plants likewise
.
In ocean water the ratio of soda (Na2O) to potash (K20) is See also: loo : 3.23 (Dittmar); in kelp it is, on the See also: average, too : 5.26 (See also: Richardson)
.
Ashes particularly See also: rich in potash are those of burning nettles, See also: wormwood (See also: Artemisia absinthium), tansy (Tanacetum vulgare), See also: fumitory (Fumaria officinalis), and See also: tobacco
.
In fact, the ashes of herbs generally are richer in potash than those of the trunks and branches of trees; yet, for obvious reasons, the latter are of greater industrial importance as See also: sources of potassium carbonate
.
According to Liebig, potassium is the essential alkali of the animal See also: body; and it may be noted that See also: sheep excrete most of the potassium which they take from the land as sweat, one-third of the See also: weight of raw See also: merino consisting of potassium compounds
.
To See also: Sir See also: Humphry See also: Davy belongs the merit of isolating this element from potash, which itself had previously been considered an element
.
On placing a piece of potash on a platinum See also: plate, connected to the negative of a powerful electric battery, and
ordinary merit
.
Curious if not very See also: artistic bills have been produced in See also: Russia; and in See also: Austria See also: good See also: work has been done by Orlik, Schliessmann, See also: Oliva and Hynais
.
In the See also: United States of See also: America, however, with the exception of some designs by Matt See also: Morgan, few posters of artistic See also: interest were produced before 1.889, in which See also: year See also: Louis J
.
Rhead commenced a notable series of decorative placards
.
Will H
.
Bradley began to produce his curious decorative
See also: grotesque posters a little later
.
If See also: American artists are behind Europeans in the artistic designing of large posters they have no rivals in the production of small illustrated placards for publishers of books and magazines
.
Chief among those who have devoted themselves to this branch of See also: poster design is See also: Edward Penfield
.
Others who have achieved success in it include Maxfield Parrish, Ethel See also: Reed, Will Carqueville, J
.
J
.
See also: Gould, J
.
C
.
Leyendecker, See also: Frank Hazenplug, See also: Charles Dana
See also: Gibson, Will Denslow, Florence Lundbourg and See also: Henry Mayer
.
Exhibitions of artistic posters have been held in the chief cities of
See also: Europe and America, and the illustrated placard has already a literature of its own
.
In See also: England a monthly See also: magazine (The Poster) was for a See also: time specially devoted to its interests, and col-lectors are numerous and enthusiastic
.
See Ernest Maindron, See also: Les Afches illustrees (See also: Paris, 1895); Les Maitres de l'affcche (Paris) ; Les Affiches etrangeres illustrees (Belgium, Austria, See also: Great Britain, United States, Germany and See also: Japan) (Paris, 1897) ; Charles Hiatt, Picture Posters (See also: London, 1895) ; J
.
L
.
Spousel, Das Moderne Plakat (See also: Dresden, 1897) ; Arsene Alexandre, M
.
H
.
Spielmann, H
.
C . See also: Bunner and A
.
Jaccacci, The See also: Modern Poster (New See also: York
.
1895)
.
' (C
.
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