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f\\t]h. It is diflinguiflud fpecifically by the :ipcitui-c being 

 of a linear form, and having the joints of the whorls elevated. 

 Thio is a niimitc (hell of an opake white colour, and has 

 been found on the fliore of Sluppy ifland. 



Calcar, ill Enlomolf.gy, a fpecies of Curcui.io, the co- 

 lour of which is black: thighs with a finglc tooth: antenns 

 a-;d feet tcllaceouf. I'abricius. This is a fmall infcft, and 

 inhabits Germany. 



Calcar, \\\ Geography, a town of Germany, in the cncie 

 f>f Wtftphalia, and duchy of Cleves, about 5 miles from 

 the Rhine. It contains two convents and two churches, 

 one for Roman Catholics, and one for Proteftants, and 

 all other fefts are tolerated; 5 miles S.E. of Clevts. N. 



lat. 5i°47'- E-lo"K- ."i^''- ^ , „ 



Calcar, in G'a/s-nuiiiii^', is the name of a fm;ill oven, or 

 reverberatory furnace, in which the lirll calcination of fand 

 and fait of pot-afhcs is made, for the turning them into what 

 they call frit. 



CALCAIIATA, in Entomolngy, a fpecies of 1'juprestis 

 that inhabiis Germany. The wing-cafes are bidentated, 

 nnd fomewhat ftriated : fliLinks of the middle pair of legs 

 toothed : body coppery. Scliall. Herbil gives this the 

 name of Bupreilis aruginofa. 



Obf. This is of a fmall fize, with four (Irias on the 

 vviniT.cafes, and a fingle black blue hue on the thorax. 



cfALCARATUS, an European fpecies of Cerambyx, 

 oFa violaceous-black colour, with rufous thighs, the poilerior 

 ones denlated. Scop. Ann. Hill. 



Calcaratus, a tpecies of Cimex, of a fufcous colour, 

 with the abdomen fanguineous above, and the poilerior 

 thighs fix-toothed. Fabncius. InhabitsTlurope. 



CALCAREOUS, fomething that partakes of the na- 

 ture and qualities of calx, or lime. 



Calcareous atmenls. See Cements calcareous. 

 Calcareous Mr//i. See Lime. 



Calcareous earth, in jigriculture, a fort of earth in 

 which calcareous matter abounds. Earths of this kind have 

 the following properties in common : — They become friable 

 when burnt in the fire, and afterwards fall into a fine white 

 powder, v\-hich is promoted, if after being burnt, they be 

 thrown into water, by which a Itrong heat ariles, and a par- 

 tial folntion takes place. They cannot be melted by them- 

 felves into glafs in a clofe fire ; but when burnt, they aug- 

 ment the caufticity of pot-afhes, and they are diffolved in 

 acids with effervefcence. This earth is found pure, in the 

 form of a powder, in fome places, and called by chimilfs 

 lac luna. It is of a white colour, and is met with in fome 

 moory fituations, at the bottoms of lakes, and in the fiifures 

 of free-llone quarries, in fome of the midland diftrifts. In 

 fome countries, as Sweden, the colour varies to red and yel- 

 low. This is fuppofcd to be lime-done walhed from the 

 rocks, and pulverized by the motion of the water. It is, 

 however, found in quantities too fmall to admit of ,any 

 applications to agricultural purpofes. It is frequently met 

 with in a friable or compaft Hate in the form of chalk. The 

 white chalk is the pureli, yet it contains, according to lord 

 Dundonald, a little filiceous, and about two f>er cent, of ar- 

 gillaceous earth. There is more £xcd air in chalk than in 

 any other calcareous earth, generally about (orty per cent. 

 It is alfo feen in a hard or indurated ftate in lime-ftone ; and 

 united with the fulphuric or vitriolic acid, in the form of 

 gypfum, felenite, or what is generally termed plaller of 

 Paris. It is hkcwife combined with clay in the form of 

 marl. See Lime-stone, Gypsum, and Marl. 



It is maintained by lord Dundonald, in his treatife on the 

 "ConncftioB of Agriculture with Chcmiftry," "that it con- 

 ftitutes not only the furface, or foil, but likewifc the under 



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.1. 



flratum of many countries to a very great depth ; and that I 

 under this general name of calcareous matter are included 'i 

 chalk, marble, lime-ftone, coral, fhells, &c. The three firll i 

 mentioned are frequently mixed with iron, and v\ith difftrent 

 proportions of the fimple earths, hut are confidtred as caU ■ 

 careous when the proportion of that earth predominates. 

 This material is capable of abforbing, and of rctaining^ 

 III niliire, though in a confiderably lefs degree than clay. 

 By the adlioii of the fire it becomes hme, and returns again 

 to the Itate of chalk or calcareous matter, by expofure to 

 the air or atmofphere." And it is Hated by Dr. Fordyce, 

 in his " Elements of Agriculture and Vegetation," thau 

 when combined with gas or fixed air it is termed ii.i/J, but 

 that when free from it, AncauJUc; that calcareous earth, 

 when mixed with clay, gives a greater friablh'ty to it than 

 fand decs ; that it unites with fulphur, forming hcpar ful- 

 phur'is ; and with animal and vegetable fubftances, forming 

 a foap. It prevents putrefaftion. It attraCls acid.s more 

 ftrongly than volatile alkali or magnefia. If it be expofed to \ 

 the air, it attrafls from it the fixable air, and reverts to 

 the ftate it was in before it was burnt. Mild calcareous ■ 

 earth forwards putrefaftion. It is foluble in water, and 

 when reduced to the Hate of a powder, and spplied to a foil, 

 it is apt to be waflied through it. Cauftic volatile alkali will 

 not precipitate calcareous earth, if diffolved in an acid ; but 

 fixed vegetable alkali will. This dilHnguilTies it from the 

 other earth?. Vitriolic acid will not didolve it, fo as to form 

 a clear folution ; and if this acid be added to a folution of it 

 in any other, it will make a precipitation. 



It is fuggefttd by the author of Phytologia, that one 

 great ufe of calcareous earth confifts " in its uniting with 

 the carbon of the foil in its pure or cauflic ftate, or with that 

 of the vegetable or animal recrements, during fome part of 

 the proceis of putrefaftion ; and thus rendering it foluble in 

 water, by forming an hepar carbonu. fomewhat like an hepar 

 fiiiphiiih produced by lime and fulphur, by which procefs, it 

 is fuppofed, the carbon is rendered capable of being ab- 

 forbed by the lafteal veffels of vegetable roots. The black 

 liquor which flows from dunghills is, it is thought, probably 

 a liuiJ of this kind; but the author fpeaks hypothetically, 

 as he has nut verified it by experiment ; and the carbon may- 

 be fimply fupported in tlie water by mucilage, like the coffee 

 drank at our tea tables; or may be converted into an hepar 

 carbon'ts by its union with the fixed alkali of the decaying 

 vegetable matter, or by the volatile alkali vifhich accompanies 

 fome ftages ot putrefadlion." And a fecond mode by which, 

 it is believed to affift the purpofe of vegetation " is by its 

 union with carbonic acid, and rendering it thus foluble in 

 water in its fluid ftate, inftead of its being expanded into a 

 gas; and thus a great quantity of carbon may be drank up. 

 by vegetable abforbent veflcls. In the prattice newly in- 

 vented of watering lands by driving ftreams over them for 

 many weeks together, it has been faid, that water from 

 fprings is generally more eifeftual, in promoting vegetation, 

 than that from rivers ; which, though it may in part be 

 owing to the azotic gas, or nitrogen, contained in fome 

 fprings, as thofe of Buxton and of Bath, according to the 

 analyfis of Dr. Prieftley, and of Dr. Pearfon, yet it is fup- 

 pofed to be principally owing to the calcareous earth, which 

 abounds in all fprings, which pafs over marly foils, or 

 through calcareous ftrata ; and which does not exift in rivers, 

 as the falts wafhed into rivers from the foil all feem to de- 

 compofe each other, except the marine fait, and fome mag- 

 nefian fait which are earned down into the ocean. The 

 calcareous earth likewife, which is wafhed into rivers, enters 

 into new combinations, as into gypfum, or perhaps into fi- 

 liceous fand, and fubfides." And » ftill farther mode in 



which 



