715 



CHAIN SHOT. 



CHALK. 



710 



was absolutely and unconditionally an equivalent iu value to oiieof 

 the others. 



CHAIN SHOT. Two iron balls linked together by a chain eight or 

 teii inches long are so called. They were formerly used on board ship. 



CHALCrDICUM, an apartment separated by a partition from the 

 Iwdy of a basilica or other large building. The name, Festus says, is 

 derived from the city Chalcis. Vitruvius (v. i.) directs that chalcidica 

 should be constructed at the ends of a basilica, if the area is dispropor- 

 tionately long. [BASILICA.] A building has been discovered in Pom- 

 peii which appears to be a chalcidicum from the inscription : 



Eumachia. L. F. Sacerd. Public. Nomine. Suo. Et. 

 M. Numistri. Frootonis. Fili. Chalcidicum. 



Cryptam. Porticum. Concordite. Augustie. 

 Pietati. Sua. Pequnia. Fecit. Eademquc. 

 Dedicavit. 



The chalcidicum is, in this instance, considered to be au inclosed 

 .-.pace or vestibule at the end of the open area of the building, in the 

 i eutre of which space a large semicircular recess has been formed. 

 The entire structure, at Pompeii, consists of a large area, about 

 130 feet by 65, surrounded by a double gallery, and has in front a 

 pseudo-dipteral portico of eighteen columns elevated on pedestals. 

 Under the centre of the portico was the great public entrance, 

 was closed with folding doors, turning in sockets of bronze, and 

 secured by bolts. On each side of the entrance there are two 

 large circular recesses, and beyond these again are raised platforms, 

 the staircases to which still remain. By a reference to the annexed 

 plan, the large area of this building will be seen, with the solid desks 

 or places for exhibiting goods, possibly cloth, for sale. The area was 

 surrounded with a beautiful marble colonnade. Under the colonnade, 

 at the end opposite the entrance, is the large recess (A), with offices (B) 

 adjoining, which is considered to be the chalcidicum, and possibly was 



[Plan of the Chalcidicum at Pompeii.] 



a commercial tribunal, or perhaps a place for ratifying mercantile con- 

 tracts, 4c. Behind the colonnade is a gallery called crypto-porticus (c), 

 cither for winter use or a depositary for goods. At the back of the 

 I'halcidiuuui there is a passage entrance (D) leading into the crypto- 

 porticus ; and near this entrance into the crypto-portieus is a statue (K) 

 of a certain Eumachia, erected by the fullonei (cloth-scourers) of 

 Pompeii to her memory. It is not improbable that there was a double 

 gallery over the colonnade and crypto-porticus, from the circumstance 

 of a staircase at E. 



The term chalcidicum appears sometimes to have been applied to a 

 sort of large porch attached to the entrance of a building ; sometimes 

 to a chamber <>r chambers by the tribune reserved for the use of the 

 judges ; but the specific use of the term is by no means certain. The 

 word occurs on the Monumentum Ancyranum, in connection with 

 Curia and Templum. 



CHALDRON, an old measure, containing thirty-six heaped bushels. 

 The word appears to come from rahlarium ; in French chaudron, or 

 ckaticlrilrt. Richelet observes that brewers, sugar-refiners, dyers, &c., 

 make use of the chamlrilre. Ite proper signification, of a large metal 

 vessel, or boiler, was probably transferred among us to denote a large 

 measure of capacity. It was chiefly used in the sale of coals which by 

 an act 5 & 6 Wm. IV. c. 63, are now sold by weight. 



ClKALK (in Geology), a rock which forms the higher part of a series 

 >r group termed cretaceous. 



< 'hulk is composed of nearly 44 parts of carbonic acid and 56 of lime. 

 It is extensively used iu agriculture to improve various soils. The 

 best land for the growth of wheat contains a certain portion of argilla- 

 ceous, siliceous, and calcareous earth ; and when this last is deficient, 

 the addition of chalk improves the soil more than any quantity of 

 animal or vegetable manure could do alone. Lime produces a greater 

 effect by its caustic nature ; but as it in always put nil the land in 

 much smaller quantities than chalk, it does not so permanently improve 

 it. Good chalk should lie firm ami compact, should break readily, and 

 crumble into a line |>wdt;r; it should readily absorb moisture, and 

 when the lumps are exposed to frost after having been wet, they 

 should break into minute square fragment*, (,'lialk is called a manure, 

 and it is so, in as far us everything which increases the crop may be so 

 called; but it is a great mistake to snppnsi; that it may be substituttd 

 for animal and vegetable manures. ( 'balk may so far supersede dung 

 that where it is used a portion of the latter may be dispensed with; 



but its chief use is to improve the texture of the soil, and render it 

 better adapted to receive and retain moisture, so that a smaller 

 portion of dung will have a greater effect than a larger would without 

 it. No good agriculturist will trust to chalk alone on poor exhausted 

 laud, although he may do so where the soil is full of nutritive matter. 

 In this last ca^e however lime would be much more eS'ectual ; but 

 chalk will make dung work well, and hence it is most frequently 

 mixed into a compost with it, or alternate heaps of dung and chalk 

 are put upon the land and mixed in the spreading. When chalk is 

 used, it is of great importance to ascertain whether the natural soil 

 contains more or less of calcareous matter. The le of this matter is 

 found in it on analysis, the greater improvement is produced by 

 chalk; hence the common saying, that " the farther you are from a 

 chalk-pit, the more valuable is the chalk." 



The soils most improved by it are the strong wet clays, which con- 

 tain a portion of iron. Chalk acts as au absorbent, corrects astringency, 

 and prevents, by its interposition between the particles of clay, that 

 running into a solid mass, which is so detrimental to the roots of 

 plants by entirely excluding atmospheric air. On loose sands its effect 

 is different ; there it acts chiefly as a cement, and the more argillaceous 

 it is, the better it binds the siliceous particles. For light soils marl is 

 preferable, especially when a considerable coat can be put on the land. 

 The clay which is so abundantly used in some parts of Norfolk, and is 

 found in many places at a small depth below the surface, owes much 

 of its virtue to the calcareous matter which it contains, and where this 

 is deficient, it will not much improve the soil until chalk or lime be 

 added. Chalk is used wherever it can be procured within a moderate 

 distance, and the soil is stiff; as in the counties of Essex, Suffolk, 

 Berkshire, Middlesex, Buckinghamshire, and many others. In those 

 districts where chalk is much used, it is generally put on the land in 

 autumn, and not ploughed in till it has been exposed to the frost ; or 

 it is laid in long heaps on a headland, or by the side of a road or lane, 

 and there turned over and mixed with the earth on which the heaps 

 are laid. If it be exposed to the sun in summer, it must be carefully 

 covered with earth, or it will harden so much by drying that it will be 

 very difficult to pulverise it afterwards, and the frost will not have the 

 same effect upon it. Ten tumbril loads of chalk, and as many of good 

 farm-yard dung, are a very good dressing either on a fallow for wheat 

 or previous to sowing turnips. When chalk is laid on permanent 

 meadows, it promotes the growth of white clover ; but except the 

 meadows are wet and produce rushes, it is of uo very great benefit to 

 the grass, although it shows its effect when the grass is broken up. 

 When land is cultivated according to the convertible system, the best 

 time to put chalk on the land is when it is about to be ploughed up. 

 If the grass is fed off the last year, the chalk may be put on during the 

 preceding winter, and simply spread over the grass ; it will thus be 

 pulverised by the frost, will sweeten the pasture, and its full effect will 

 be perceived in the first grain-crop after the land is ploughed up. 

 When chalk has been some time on the laud, it is gradually carried 

 below the soil by the filtration of the surface-water, and by the action 

 of earthworms, which are continually carrying upwards and depositing 

 on the surface the fine earth removed from below the chalk dressing. 

 After a few years therefore it requires to be renewed, which shows the 

 advantage of putting on a moderate quantity and repeating it in six or 

 seven years, in preference to putting on a large quantity at once, 

 unless where lands are reclaimed from a state of waste, and require to 

 be improved by a large admixture of calcareous matter before they can 

 be made productive by enriching manures. This is the cose with those 

 yellow loams which contain much iron, and which are generally found 

 under the trim pan, so well-known to all those who improve poor light 

 heath-laud. [BARKEN LAND.] The quality and effects of chalk as a 

 dressing depend, not only on the deficiencies of the soil to which it 

 may be applied, but also on its own varying composition, and that 

 chalk is best, which is found to contain the largest per ceutage of 

 phosphate of lime in addition to the calcareous and clayey parts of 

 which it mainly consists. 



An important use of chalk is to form ponds in porous soils for the 

 use of cattle. A stratum of chalk a few inches thick, protected by a 

 coat of gravel and sand to prevent its being trod through, will 

 effectually retain the water ; and if a considerable proportion of salt is 

 beat up with it and intimately mixed, it will effectually prevent worms 

 from making lodgments in it, and keep in water for a very long time. 

 It is of advantage to throw chalk into all ponds used by cattle ; it 

 corrects any acidity which may arise from stagnation, and the water in 

 which chalk is diffused, is more wholesome than that which contains . 

 clay alone. In fattening calves chalk is of the greatest use ; it may be 

 laid in the calf-pens for them to lick, which they will readily do, or it 

 may be scraped and mixed with a small quantity of salt, and laid in a 

 small manger within the reach of each calf. It effectually prevents 

 scouring, and keeps their digestion in a proper state. 



In many parts of England the whole sub-soil to a great depth is a 

 solid mass of chalk, and the earth which covers it contains very little 

 else than carbonate of lime, with a small portion of vegetable matter 

 in a decomposed state. In this soil a short sweet herbage grows, which 

 is extremely grateful to shuep ; according the chalky hills, called 

 downs, in Sussex, Wiltshire, &c., are chiefly devoted to sheep-pasture. 

 Along the sides of these hills, where the waters continually accumu- 

 late the finer particles of the soil which are washed down from above, 



