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Zeolite. feffed by no other fubftance, except lapis lazuli, which intumefces only in a very high heat, and gelatinates only after calcination. ift, As to gelatination. Mr. Swab obferved, that a’ mixture of equal parts, fine clay and liine, forms a glafs vvhich gelatinates with acids. So does a melted mafs of equal parts, lime and quartz. 2 Mem. Swed. p. 443*. The cla y the former experiment alfo contains filex. Mr. Pelletier found the filiceous ore of zinc, alfo to gelatinate, but does not intumefce. On the other hand, all zeolites do not gelati nate, per Mr Swab, 2 Mem. Swed. 455. 3 Bergm. p. 228. The zeolites of Haelleftadt alfo gelatinate, but not, until previoufly calcined, per Mr. Swab, Swed. Abhandl. 1784» p. 60. The zeolites of the Hartz do not gelatinate; nei- ther do the cryllallized of Iceland, or Feroe, as fome fay *. Again, as to inlutntfcence, feveral ftones mtu- naefee before fufion, as prehnite, thumerftein, &c. Lilalite, and feveral zeolites, do not intu- mefee, per Bergman, Swed. Abhandl. 1784, p. 115. or only very flightly. As zeolites imbibe water, they frequently efflo- refee by expofure to the air; and as they exift in a rounded form in traps, the cavities in thefe frequently arife from the talling or walhing out of the mouldercd zeolites. This ftone often paffes into calcedony. * Lafnjs Hartz, p. 335- ' Lerape Maga. p. 59. 21 ft Species«