GEO?.OOV.] N ATU]R,4J? H!8'roRY. 597 the former, ?d while ?e de?mi?ou ? mlmii? ca{ca?u? mat' ?r w? ?ti}l iu p?gresm, the portions Brat conmo{idaied must have ?eu mhat?d by c?mide?ble violence. But, w?e? no such fia?en? e?st, t?e uuequ? dieusion of componeu? at first uniformly mixed,?d even the ?ormatiou of nodules differing in proportions fwm ?e p? which surrounds ?em, may ?rhapa admit of expiration, by some pr?eaa ?alo?us to what takes place in the preparation of the com- aurid of which the ordin? earleaware ia m?ufactured where, ?ough. ? ingr?ien? ? divided by m?hanicai at&tion only, a ao? of chemical action produces, under cef- tin circussmuts, a new arrantsent of ?e pa?'. And this explana6on may, pro?bly, ? ex?nded to those n? dular concretions, generally consider? ? eon?mpomneous 'with ?e p?te in which ?ey are envelo?d, the distinction of which, from conglomem?a of mech?ical origin, forms, in many cases, a difficulty in geolo?. What the degree may be, of subdivision required to dispose the pa. icles to act thus u?n each other, or of fluidity to admit of their action, remains 8?ll to be de?ined.
- ?e day and p?vedz? fiin? am e?bined for the une of
?r, by ?ing tint sedately diffu?d in w?r to the comi?me of tMck etonre, and when mix? in due ?on ?e r?ne? p?r eon?nteme by e?mtion. During'thin pr?s? if the z?mtiou ? n? ?pid and i?ia?, or if the iu?ients leR to ?t on e?h ?r, even for ?znty-four h?., ?e flinty p?- ?cle8 uui? in? ?dy ?ns, ?d the m?8 ?ome8 unfit for p?o?8 of t? m?u?u?r. I ? iudeb? for t?8 f? which, l.?lieve, is well k?wn in ?me of the ?des, ? my fde?' Mr. A?hur ?kiu. ?d Mr. H?hel info?a me, that a ?Xc?ge ?k? pl?e in ?ently p?ipi?t? carenate of ?r; which, if le? long moh? conc?8 in? h? of a ? c?our, much ? d?cui?y Mluble in ?mouia than t? 0? ?pi?.
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