Page:The American Cyclopædia (1879) Volume IV.djvu/240

 232 CHALKLEY CHALLENGE shells, sponges, &c., into the most minute pores of which the silica has penetrated, beautifully preserving their peculiar forms. The chalk it- self is in great part composed of finely commi- nuted shells and corals, and it is now generally understood to have been derived from the same sources as the fine white calcareous mud which fills the bottoms of coral lagoons, and the in- terstices of its structures. This proves to be entirely of animal origin, in part finely ground shells and corals, and partly the excrement of shell fish, and of certain gregarious fishes, which in the coral regions of the Pacific were seen by Darwin through the clear waters, browsing quietly in great numbers upon living corals, like grazing herds of graminivorous quadrupeds. In the coral reefs of the south seas Prof. Dana found portions of these as com- pact and solid as any secondary limestone, and parts of the still growing structures not to be distinguished from portions of the chalk rocks of the cretaceous formation. The fossils of this geological group are all of oceanic families, but of extinct species. Several species found in New Jersey are identical with those of the same formation in Europe; but the chalk is absent, though the other strata of limestone and greensand are recognized as those which elsewhere accompany it. Chalk is employed for a variety of purposes. It is easily con- verted into lime, in which state it forms a val- uable fertilizer as well as cement. It is used as a marking material, and also for polishing metals and glass. When finely ground, and purified by washing and separating its harder particles, it is sold by the name of whiting, or Spanish white. The flints found in the forma- tion were once much used in England in the manufacture of glass. In medicine, chalk, when thoroughly purified, is used, under the name of prepared chalk, as an absorbent in diarrhoea ; it is also an antacid, and is used to furnish carbonic acid gas ; it is also a dentifrice. Chalk mixture is the form in which prepared chalk is commonly administered medicinally. "When diarrhoea depends upon irritation or in- flammation of the mucous membrane of the bowels, it should not be employed, for it is then more likely to increase than allay the disturbance. It may often be advantage- ously combined with -opium or astringents, or both. French chalk is a pure variety of steatite or talc, used by tailors for marking cloth, and also mixed with cosmetics to give them body. Black chalk is a variety of bitu- minous shale, made use of by artists for draw- ing. Red chalk, or reddle, is an argillaceous red oxide of iron. CHALKLEY, Thomas, a preacher of the society of Friends or Quakers, born in London, March 3, 1675, died in the island of Tortola, West Indies, Sept. 4, 1741. At the age of 20 he was pressed on board a man-of-war, but after a day's deten- tion was discharged on account of his scruples about bearing arms. He engaged in trade for a while, and having made a little money became an itinerant preacher. He went to America in 1698, landing in Maryland and travelling for a year in Virginia and New England, after which he returned home and married. He then decided to remove permanently to America, made his home in Philadelphia, and spent the rest of his life mainly in travelling and preach- ing in the English colonies. In 1707 he visited Europe, and after travelling through the Brit- ish islands made an excursion to Holland and Germany. He went several times to the West Indies, and was engaged in the work of his itinerant ministry at Tortola when he died of fever after a few days' illness. He left an in- teresting journal of his " Life, Labors, Travels," &c., which was published with a collection of his writings at Philadelphia in 1747, and was reprinted in one volume in New York in 1808. By a bequest in his will he founded the library of the four monthly meetings of Friends at Philadelphia. CHALLENGE. This word, which is now, ex- cept in a legal sense, used chiefly to imply a provocatory summons to mortal combat, seems originally to have conveyed within itself the idea of an appeal, of an exception taken, or a claim asserted, and a disinclination to submit to some decision or arbitrament, rendered or about to be rendered, and removal of the sub- ject matter of dispute to some other court or tribunal. Thus, in ancient times, the duello was never the mode of settlement of an angry personal dispute ; but it was the trial of a sol- emn cause before the actual court and in the presence of God. The challenger took ex- ception to the truth of the allegation made against him by his adversary or opponent, and removed the adjudication of the cause, by ap- peal of challenge, from the human court of law, before which it was pending, to the di- vine court of equity, which was believed di- rectly to interfere in the event of wagers by battle, and to give the strong arm and the sharp sword to the righteous party. In the same sense, when a jury is challenged, whether by the array or by the poll, exception is taken to the fairness of the impanelling of the whole jury, or to the partiality of the individual juror ; and, having taken exception, the per- son accused by his challenge removes the ad- judication of his cause from that entire jury, or from that individual as part of it, to some other, by whom he believes he can have a fair trial, which he denies that he can as it is at present constituted. Challenges to jurors are either to the array, which is to the whole panel, and founded upon some error or par- tiality on the part of the officer summoning them, or to the polls or individual jurors sep- arately. The latter may be either peremptory or for cause. A certain number of peremptory challenges is allowed in criminal cases, for which no reason need be assigned ; but for others legal cause must be given, the sufficiency of which will be determined by the court, or may be referred to triers, if depending upon